Abstract
In construction projects, the relationship between project cost and duration, which is one of the main factors of the project, are considered the parameters decision-makers. When a construction schedule is planned by the planners, additional resources are allocated to shorten the project duration considering the completion time and cost of the activities so that the most suitable construction schedule is prepared by providing a trade-off between project duration and total cost. In the case of time-cost trade-off problems, the total cost of the project is determined by summing each activities’ cost by adding indirect costs. Moreover, total project duration is determined by obtaining total project duration after CPM (Critical Path Method) calculations. Obtaining optimum duration and costs is such a problematic issue with using conventional methods and common software packages. These techniques consider deterministic project values and include CPM calculations for fitness value calculation. Moreover, current studies defined alternatives as non-variable discrete values. However, construction projects are dynamic processes, and quantities are prone to be changed related to project size. In this study, time-cost trade-off optimization is performed by using harmony search method with introducing different implementation that can be more easily used for different projects. The model is implemented in a real construction project, and the conclusions are interpreted.
Time-Cost Trade-Off Analysis in a Construction Project Problem: Case Studyijceronline
In construction project, cost and time reduction is crucial in today’s competitive market respect. Cost and time along with quality of the project play vital role in construction project’s decision. Reduction in cost and time of projects has increased the demand of construction project in the recent years. Trade-off between different conflicting aspects of projects is one of the challenging problems often faced by construction companies. Time, cost and quality of project delivery are the important aspects of each project which lead researchers in developing time-cost trade-off model. These models are serving as important management tool for overcoming the limitation of critical path methods frequently used by company. The objective of time-cost trade-off analysis is to reduce the original project duration with possible least total cost. In this paper critical path method with a heuristic method is used to find out the crash durations and crash costs. A regression analysis is performed to identify the relationship between the times and costs in order to formulize an optimization problem model. The problem is then solved by Matlab program which yields a least cost of $60937 with duration 129.50 ≈130 days. Applying this approach, the result obtained is satisfactory, which is an indication of usefulness of this approach in construction project problems.
This document summarizes a research study that uses differential evolution algorithm to solve the multi-objective optimization problem of balancing time, cost, and quality in construction project planning. The study models the time, cost, and quality objectives and formulations. It then applies differential evolution algorithm to analyze two case studies and compare the results to other existing approaches. The study finds that differential evolution algorithm efficiently locates optimal solutions with minimum function evaluations for the time-cost-quality tradeoff problem.
Negative Total Float to Improve a Multi-objective Integer Non-linear Program...IJECEIAES
This paper presents Multi-Objective Integer Non-Linear Programming (MOINLP) involving Negative Total Float (NTF) for improving the basic model of Multi-Objective Programming (MOP) in case the optimization of the additional cost for Project Scheduling Compression (PSC). Using the basic MOP to solve the more complex problems is a challenging task. We suspect that Negative Total Float (NTF) having an indication to make the basic MOP to solve the more general case, both simple and complex of PSC. The purpose of this research is identifying the conflicting objectives in PSC problem using NTF and improving MOINLP by involving the NTF parameter to solve the PSC problem. The Solver Application, which is an add-in of MS Excel, is used to perform optimization process to the model developed. The results show that NTF has an important role to identify the conflicting objectives in PSC. We define NTF is an automatic maximum value of the activity duration reduction to achieve due date of PSC. Furthermore, the use of NTF as a constraint in MOINLP can solve the more general case for both simple and complex PSC problem. Base on the condition, we state that the basic MOP is still significant to solve the PSC complex problems using MOINLP as a sophisticated MOP technique.
The document discusses perceptions of time, cost, and quality (TCQ) management on building projects based on a survey of clients, architects, quantity surveyors, engineers, project managers, and contractors in South Africa.
The key findings from the survey include:
1) Clients rated quality as more important than time, contrary to other project participants.
2) Most clients believed the procurement team matched their needs to appropriate procurement systems, but the procurement team did not generally see this as true.
3) Clients believed they rarely changed original project briefs after starting, but consultants saw brief changes occurring more often.
4) Perceptions varied on whether projects were completed within agreed budgets, with
A Study on Project Planning Using the Deterministic and Probabilistic Models ...IJERA Editor
Project planning is the important task in many areas like construction, resource allocation and many. A sequence of activities has to be performed to complete one task. Each activity has its unique processing time and all together to identify the critical activities which affect the completion of the project. In this paper the probabilistic and deterministic models to determine the project completion time and also the critical activities are considered. A case study on building construction project has been performed to demonstrate the application of the above said models. The two project scheduling namely PERT and CPM are used to determine numerically the different types of floating times of each activity and hence determined the critical path which plays an important role in the project completion time. Also a linear programing model has been developed to reduce the project completion time which optimize the resource allocation. To apply these techniques numerically the primary data from a housing project company in a metropolitan city has been taken, the network diagram of the activities involved in the building construction project has been drawn and the results are tabulated
Strategic Cost Management for Construction Project Success : A Systematic Studycivej
Large construction projects are inherently complex and dynamic. Many projects start with good ideas,
huge investments and great efforts. However, most of them do not achieve much success. A major
contribution to unsuccessful projects is the lack of understanding on scope, time, cost and quality. Projects
as powerful strategic weapons when initiated create economic value and competitive advantage. The
objective of the research is to explicitly declare the scope of the research to by considering only the scope,
time, cost and quality as process success parameters and how specifically the cost element would influence
the project success when all other elements or factors other than cost are represented in terms of cost
factor along with the contract conditions as basic rules or constraints that drive the strategic cost based on
applying the CRASP methodology concept. The concept of benchmarking would provide right meaning of
project success when allowing to properly distributing the meaning of customer profitability to the project
providers (project owner and contractors).
Towards Innovate Methods of Construction Cost Management and Controlcivej
Project cost is one of the three main challenges for the construction manager, where the success of a
project is judged by meeting the criteria of cost with budget, schedule on time, and quality as specified by
the owner. Many projects experience extensive delays and thereby exceed initial time and cost estimate.
Available information, good estimating practice and experienced personnel are some of the factors found
to have considerable impact on estimation accuracy. The successful execution of construction projects and
keeping them within estimated cost and prescribed schedules depend on a methodology that requires sound
engineering judgment. So the research aim is to conduct research study and process of exploring the
existing model related to above three types of estimate and their contribution to civil engineering cost
management and control especially getting motivated with the verification and validation component of
CRASP methodology. The objective of this paper or scope of this research in this paper is to conduct
literature study and review towards exploring innovative techniques such as Artificial Intelligence
Techniques or Expert System Techniques available and applicable to make decision making or decision
support regarding construction cost management and control at three levels: (i) before the actual civil
engineering project design begins (ii) after detailed design but before execution and (iii) during project
execution
Time-cost-risk optimization in construction work by using ant colony algorithmVISHNU VIJAYAN
This document discusses using an ant colony optimization algorithm to optimize the time, cost, and risk of construction projects. It begins by explaining that time and cost are important factors for construction projects, and that considering risk is also important for meeting expectations. It then describes using an ant colony algorithm, which models the behavior of ant colonies, to evaluate different combinations of activity durations and resources to find a optimal balance between minimizing time, cost and risk. The document provides an example of applying this approach to a sample 7 activity construction project, evaluating various resource options and their associated time, costs and risks.
Time-Cost Trade-Off Analysis in a Construction Project Problem: Case Studyijceronline
In construction project, cost and time reduction is crucial in today’s competitive market respect. Cost and time along with quality of the project play vital role in construction project’s decision. Reduction in cost and time of projects has increased the demand of construction project in the recent years. Trade-off between different conflicting aspects of projects is one of the challenging problems often faced by construction companies. Time, cost and quality of project delivery are the important aspects of each project which lead researchers in developing time-cost trade-off model. These models are serving as important management tool for overcoming the limitation of critical path methods frequently used by company. The objective of time-cost trade-off analysis is to reduce the original project duration with possible least total cost. In this paper critical path method with a heuristic method is used to find out the crash durations and crash costs. A regression analysis is performed to identify the relationship between the times and costs in order to formulize an optimization problem model. The problem is then solved by Matlab program which yields a least cost of $60937 with duration 129.50 ≈130 days. Applying this approach, the result obtained is satisfactory, which is an indication of usefulness of this approach in construction project problems.
This document summarizes a research study that uses differential evolution algorithm to solve the multi-objective optimization problem of balancing time, cost, and quality in construction project planning. The study models the time, cost, and quality objectives and formulations. It then applies differential evolution algorithm to analyze two case studies and compare the results to other existing approaches. The study finds that differential evolution algorithm efficiently locates optimal solutions with minimum function evaluations for the time-cost-quality tradeoff problem.
Negative Total Float to Improve a Multi-objective Integer Non-linear Program...IJECEIAES
This paper presents Multi-Objective Integer Non-Linear Programming (MOINLP) involving Negative Total Float (NTF) for improving the basic model of Multi-Objective Programming (MOP) in case the optimization of the additional cost for Project Scheduling Compression (PSC). Using the basic MOP to solve the more complex problems is a challenging task. We suspect that Negative Total Float (NTF) having an indication to make the basic MOP to solve the more general case, both simple and complex of PSC. The purpose of this research is identifying the conflicting objectives in PSC problem using NTF and improving MOINLP by involving the NTF parameter to solve the PSC problem. The Solver Application, which is an add-in of MS Excel, is used to perform optimization process to the model developed. The results show that NTF has an important role to identify the conflicting objectives in PSC. We define NTF is an automatic maximum value of the activity duration reduction to achieve due date of PSC. Furthermore, the use of NTF as a constraint in MOINLP can solve the more general case for both simple and complex PSC problem. Base on the condition, we state that the basic MOP is still significant to solve the PSC complex problems using MOINLP as a sophisticated MOP technique.
The document discusses perceptions of time, cost, and quality (TCQ) management on building projects based on a survey of clients, architects, quantity surveyors, engineers, project managers, and contractors in South Africa.
The key findings from the survey include:
1) Clients rated quality as more important than time, contrary to other project participants.
2) Most clients believed the procurement team matched their needs to appropriate procurement systems, but the procurement team did not generally see this as true.
3) Clients believed they rarely changed original project briefs after starting, but consultants saw brief changes occurring more often.
4) Perceptions varied on whether projects were completed within agreed budgets, with
A Study on Project Planning Using the Deterministic and Probabilistic Models ...IJERA Editor
Project planning is the important task in many areas like construction, resource allocation and many. A sequence of activities has to be performed to complete one task. Each activity has its unique processing time and all together to identify the critical activities which affect the completion of the project. In this paper the probabilistic and deterministic models to determine the project completion time and also the critical activities are considered. A case study on building construction project has been performed to demonstrate the application of the above said models. The two project scheduling namely PERT and CPM are used to determine numerically the different types of floating times of each activity and hence determined the critical path which plays an important role in the project completion time. Also a linear programing model has been developed to reduce the project completion time which optimize the resource allocation. To apply these techniques numerically the primary data from a housing project company in a metropolitan city has been taken, the network diagram of the activities involved in the building construction project has been drawn and the results are tabulated
Strategic Cost Management for Construction Project Success : A Systematic Studycivej
Large construction projects are inherently complex and dynamic. Many projects start with good ideas,
huge investments and great efforts. However, most of them do not achieve much success. A major
contribution to unsuccessful projects is the lack of understanding on scope, time, cost and quality. Projects
as powerful strategic weapons when initiated create economic value and competitive advantage. The
objective of the research is to explicitly declare the scope of the research to by considering only the scope,
time, cost and quality as process success parameters and how specifically the cost element would influence
the project success when all other elements or factors other than cost are represented in terms of cost
factor along with the contract conditions as basic rules or constraints that drive the strategic cost based on
applying the CRASP methodology concept. The concept of benchmarking would provide right meaning of
project success when allowing to properly distributing the meaning of customer profitability to the project
providers (project owner and contractors).
Towards Innovate Methods of Construction Cost Management and Controlcivej
Project cost is one of the three main challenges for the construction manager, where the success of a
project is judged by meeting the criteria of cost with budget, schedule on time, and quality as specified by
the owner. Many projects experience extensive delays and thereby exceed initial time and cost estimate.
Available information, good estimating practice and experienced personnel are some of the factors found
to have considerable impact on estimation accuracy. The successful execution of construction projects and
keeping them within estimated cost and prescribed schedules depend on a methodology that requires sound
engineering judgment. So the research aim is to conduct research study and process of exploring the
existing model related to above three types of estimate and their contribution to civil engineering cost
management and control especially getting motivated with the verification and validation component of
CRASP methodology. The objective of this paper or scope of this research in this paper is to conduct
literature study and review towards exploring innovative techniques such as Artificial Intelligence
Techniques or Expert System Techniques available and applicable to make decision making or decision
support regarding construction cost management and control at three levels: (i) before the actual civil
engineering project design begins (ii) after detailed design but before execution and (iii) during project
execution
Time-cost-risk optimization in construction work by using ant colony algorithmVISHNU VIJAYAN
This document discusses using an ant colony optimization algorithm to optimize the time, cost, and risk of construction projects. It begins by explaining that time and cost are important factors for construction projects, and that considering risk is also important for meeting expectations. It then describes using an ant colony algorithm, which models the behavior of ant colonies, to evaluate different combinations of activity durations and resources to find a optimal balance between minimizing time, cost and risk. The document provides an example of applying this approach to a sample 7 activity construction project, evaluating various resource options and their associated time, costs and risks.
Effective techniques in cost optimization of construction project an revieweSAT Journals
Abstract
In the construction project, time and cost are the most important factors to be considered in the planning of every project. The aim of project is to finish the projects on time, within budget and to achieve other project objectives. It is a difficult task undertaken by project managers in practice, which include constantly measuring progress, evaluation of plans, and corrective actions should be taken whenever required. Optimization is a systematic effort made to improve profit margins and obtain the best results under given circumstances. There is a Systematic planning and programming with effective management is necessary for timely completion of the project. there is availability of various tools and techniques for optimization. Optimizing performance of the different techniques adopted at one stage of the construction process may not be beneficial if the methods used are not to up the efficient level. In this approach we have studied various factors which affect the cost of projects. again in this approach we have studied various techniques and various materials used for cost optimization. Also the need of optimization is discussed.
Keywords: time, cost, optimization.
Improvement of the model of minimization of the costs in a time overrun conte...IAEME Publication
In the field of construction time-overruns are recurring. The construction cost optimization
model in time-overrun context (CCOMTOC) was developed to generate a new optimal schedule that
could allow minimizing the total cost of a construction project subject to penalties for delay. The
original CCOMTOC is based on the assumption that the delay on the whole project is envisaged
before the beginning of the works. In practice, the delay can be noticed either before startup, or
during the realization of a task. It is this reality that is reflected in the improvement of the original
CCOMTOC. The comparison between the improved and the original model shows a greater
reduction of the cost-overrun after skidding for the duration of the tasks.
A review of advanced linear repetitive scheduling methods and techniquesAsadullah Malik
ABSTRACT
Over the past two decades, significant attention has been focused on the development of advanced scheduling methods for repetitive/linear construction projects. Several approaches have been proposed by various research groups in order to solve specific problems in the scheduling of repetitive/linear construction projects such as high-rise buildings, bridges, pipelines, and highways. Some of these approaches represent milestones in the authors’ researches, and others provide a thorough solution implemented in computer software. This paper is a review of several articles related to this topic, which have been published in specialized journals since 1998. The solution methods for repetitive/linear scheduling problems are various, extending from simple graphical techniques to complex computational and optimization methods, such as genetic algorithms. The methods underlying the different solutions can be divided into three groups: exact, heuristic and metaheuristic. This paper presents an introduction into the different repetitive/linear scheduling problems, outlines the optimization methods proposed, classifies the different approach methods utilized and, finally, areas for future research are suggested.
Keywords: linear scheduling, construction management, repetitive units, optimization, genetic algorithms.
IRJET- Implementing Time and Cost Optimization in Commercial Building using P...IRJET Journal
This document discusses implementing time and cost optimization techniques in commercial building projects using Microsoft Project. It describes crashing activities by adding resources like workers and equipment to reduce durations, and using slack time and alternative materials to lower costs. The goal is to complete projects on time or under budget by analyzing the tradeoff between time and cost when crashing critical paths or using different building materials. Manual and software-based methods are evaluated for optimizing the schedule and minimizing total project duration and costs.
IRJET- A Study on Factors Affecting Estimation of Construction ProjectIRJET Journal
This document discusses factors that affect the accuracy of construction project cost estimation. It begins by outlining the importance of accurate cost estimation for construction projects. It then reviews previous literature that has identified various factors such as ineffective planning, design changes, weather, and material cost fluctuations.
The document describes the objectives of the study, which are to explore common cost estimation practices and identify significant cost estimation factors. It then provides more detail on the literature review, outlining several previous studies that examined factors like demand, time effects, use of rough set theory and neural networks in cost models, and factors relevant at different project stages.
The literature review discusses previous research identifying factors such as experience, project complexity, scope definition, cost data
Review of Hooke and Jeeves Direct Search Solution Method Analysis Applicable ...ijiert bestjournal
Role of optimization in engineering design is prominent one with the a dvent of computers. Optimization has become a part of computer aided design methodology. It is primarily being used in those design activities in which the goal is not only to achieve a feasible design,but als o a design objective. The paper reviews the optimization in detail followed by the literature review and b rief discussion of Hooks and Jeeves Method Analysis with an example.
Implementation of Line of Balance Method for Scheduling High-rise BuildingIJERA Editor
This document summarizes a study on implementing the Line of Balance (LOB) method for scheduling a high-rise building construction project. It begins with an introduction to LOB scheduling and its benefits for repetitive projects like high-rise buildings. It then outlines the methodology used, which includes collecting activity duration data, drawing LOB and histogram charts, analyzing the charts to determine total duration and resource needs, and crashing critical activities. The findings show crashing activities reduced the total project duration. Crew sizing was evaluated using histograms before and after crashing. It concludes LOB is useful for monitoring repetitive activities in high-rises and integrating it with critical path scheduling allows for effective activity crashing.
Cost Effective Construction Techniques By Stephen RaymentStephen Rayment UK
Stephen Rayment is the co-founder of Systech International, a company that focuses on providing cost effective construction techniques. Some secrets that Rayment emphasizes to reduce costs include developing strong supplier relationships, ensuring workers have the proper capabilities for tasks, planning future construction directions, and prioritizing customer service to meet needs. By focusing on these areas, Rayment has helped Systech International establish a reputation for delivering high quality construction projects on budget.
Resource levelling minimizes resource fluctuations by postpone the earliest start time (EST) of non-critical activities with corresponding floats. Float consumption for resource leveling may reduces the project completion probability. This paper presents a method to minimize the resource fluctuations with minimum impact of float consumption. A case study is presented to verify the validity and usability of the method.
The document discusses Project Evaluation Review Technique (PERT), a project management tool used to analyze tasks, time required, and critical paths. It describes various project management methodologies like PRINCE2, Agile, and Critical Path Method (CPM) that are suited for different types of projects. Finally, it discusses setting up an organizational structure and quality management process for a project.
The Automation of Critical Path Method using Machine Learning: A Conceptual S...Dr. Amarjeet Singh
This research aims to shed light on the use of machine learning in improving, developing and automating the critical path method, solving its problems, studying this effect and its dimensions, and discussing that from many aspects.
The research is divided into two theoretical and practical parts. The theoretical part is concerned with studying the critical path method and its advantages, problems and challenges, as well as studying machine learning and artificial intelligence and its dimensions, reviewing materials and sources related to this, and then presenting suggestions and future solutions based on this study. As for the practical section, it is a questionnaire that targeted a segment of engineers, in particular, and others who have sufficient experience in both the critical path method and machine learning, and seeking their opinions on both topics.
The result of the theoretical research was 14 theories or proposals that were presented based on the foregoing study. As for the practical questionnaire, a sample of 127 was taken. Through statistical analysis, the results were analyzed and discussed separately, and then a conclusion was drawn regarding them.
This document provides an overview of a quantitative study examining the contribution of Earned Value Management (EVM) to project success on external projects under contract. The study tested hypotheses about the relationship between EVM principles and project success, and whether that relationship differs for fixed-price versus cost-plus contracts. Key findings included that EVM principles positively predict project success, and that fixed-price contracts may benefit more from EVM than cost-plus contracts. The study contributes to understanding how EVM can improve project planning and control for different contract types.
STUDY AND ANALYSIS OF CONCRETE STRENGTH PARAMETERS USING VETIVER GRASS ASH AS...Vamsi Kovalam
The development of a new building material based on vetiver grass ash for use in the rural areas of the developing countries is experimentally investigated.
The properties of VGA were experimentally studied to consider the possibility of using VGA as a pozzolanic material.
Many developing countries are attempting to develop substitutes for cement from locally available raw materials like agricultural and industrial waste.
Fly ash ,rice husk ash and rice straw ash have been proven to be economical partial substitutes for cement
This document provides an overview of the RSMeans publication titled "Value Engineering in the Construction Industry". It includes a table of contents that outlines the various chapters in the book, which cover topics such as project budgeting, cost modeling, function analysis, life cycle costing, and case studies applying value engineering techniques. The document also provides brief descriptions of the content included in each chapter. It indicates that the book presents advances in value engineering since previous editions and includes an updated disk with additional value engineering tools and automated formats.
Cost Overrun Causes Related to the Design Phase in the Egyptian Construction ...World-Academic Journal
This document summarizes a research paper that aimed to identify and evaluate the most significant causes of cost overrun related to the design phase of construction projects in Egypt. Through a literature review and expert interviews, the researchers developed a list of potential cost overrun causes. They then conducted a survey with 101 industry professionals to quantitatively assess the frequency and impact of each cause. The results showed that the most important causes were design changes/variations and unrealistic construction time estimates. The degree of agreement between owners, contractors, architects, and project managers was also analyzed to identify any conflicting perspectives on the causes.
This research proposal aims to use concepts from chaos theory to predict project outcomes through aligning project and team objectives. The researcher will apply the concept of self-similarity in fractals to demonstrate how sustained alignment of project goals and personal goals of project managers and teams can optimize cost outcomes. The proposal provides background on definitions of project success, highlighting differences between project management success and overall project success. It also reviews literature on high failure rates of projects in various sectors such as IT, defense acquisition, and infrastructure. The researcher proposes investigating how chaos theory concepts can be applied to model project dynamics and determine basins of possible project outcomes.
The document discusses different project management techniques, focusing primarily on PERT (Program Evaluation and Review Technique). It provides an overview of PERT, including how to define tasks, estimate durations, calculate expected durations and variance/standard deviation for each task. It also discusses how to determine the critical path and calculate the probability of completing a project by a certain date. An example project is used to demonstrate how to populate a table with the necessary PERT calculations.
1. The document discusses cost estimation and management of construction projects. It outlines various factors that must be considered like project planning, scheduling, progress monitoring, time and cost estimation, cost management, change order management, and mitigating cost overruns.
2. Effective cost estimation requires considering construction methodology, resources, duration and feasibility. Time and cost have a strong relationship, as delays increase costs.
3. Cost management ensures a project is completed within budget through accurate budget preparation, crew sequencing, and cost optimization in scheduling. Change order management handles changes fairly.
This document summarizes a master's thesis that investigated implementing carpooling in new housing construction in Gothenburg, Sweden. The thesis questioned the city's parking ratio regulation. Through literature reviews, interviews, calculations, and a survey, the study found that carpooling could contribute to sustainability goals. However, the parking regulation requires special approval and offers no guarantees. Additionally, individual behaviors and societal views of car ownership complicate changing transportation choices. The thesis concluded the regulation lacks flexibility, economic rationality, and accurate demand estimation. It recommends a flexible, behavior-based approach that considers economics and potential travel impacts. Further research is needed to develop an improved regulation.
This document discusses planning and scheduling methods to optimize time and cost for the construction of a six-lane bridge with cast in situ and precast elements in Kolathur, Chennai. It reviews literature on scheduling techniques and identifies objectives like preparing a detailed schedule and cost estimate for both construction methods. The project methodology involves data collection, analysis, and comparing schedules and costs of cast in situ and precast construction to propose the best option. Schedules were prepared for both methods and costs were estimated using Excel. The research aims to minimize project duration and costs through optimized planning and use of advanced construction techniques.
A Case Study On Applying Lean Construction To ConcreteDawn Cook
The document discusses applying lean construction principles to concrete construction projects. It studies a concrete construction project to identify waste and proposes solutions. At the project level, lack of coordination among subcontractors caused schedule delays. The paper proposes using last planner concepts, linear scheduling, and graphic scheduling to improve communication and look-ahead planning. At the operation level, a systematic approach is applied to identify waste, redesign work procedures, and use 3D animation for employee training to reduce waste and resistance to changes.
An application of genetic algorithms to time cost-quality trade-off in constr...Alexander Decker
This document summarizes a research paper that develops an optimization model using genetic algorithms to solve the time-cost-quality trade-off problem in construction projects. The model aims to find the minimum cost for a construction project to meet certain quality levels within a given time limit. It does this by considering different activity execution modes and using genetic algorithms to efficiently explore the large solution space. The document provides background on optimization problems and techniques, an overview of the time-cost-quality trade-off problem and prior related research, and describes the objectives and approach of the developed genetic algorithms model.
Effective techniques in cost optimization of construction project an revieweSAT Journals
Abstract
In the construction project, time and cost are the most important factors to be considered in the planning of every project. The aim of project is to finish the projects on time, within budget and to achieve other project objectives. It is a difficult task undertaken by project managers in practice, which include constantly measuring progress, evaluation of plans, and corrective actions should be taken whenever required. Optimization is a systematic effort made to improve profit margins and obtain the best results under given circumstances. There is a Systematic planning and programming with effective management is necessary for timely completion of the project. there is availability of various tools and techniques for optimization. Optimizing performance of the different techniques adopted at one stage of the construction process may not be beneficial if the methods used are not to up the efficient level. In this approach we have studied various factors which affect the cost of projects. again in this approach we have studied various techniques and various materials used for cost optimization. Also the need of optimization is discussed.
Keywords: time, cost, optimization.
Improvement of the model of minimization of the costs in a time overrun conte...IAEME Publication
In the field of construction time-overruns are recurring. The construction cost optimization
model in time-overrun context (CCOMTOC) was developed to generate a new optimal schedule that
could allow minimizing the total cost of a construction project subject to penalties for delay. The
original CCOMTOC is based on the assumption that the delay on the whole project is envisaged
before the beginning of the works. In practice, the delay can be noticed either before startup, or
during the realization of a task. It is this reality that is reflected in the improvement of the original
CCOMTOC. The comparison between the improved and the original model shows a greater
reduction of the cost-overrun after skidding for the duration of the tasks.
A review of advanced linear repetitive scheduling methods and techniquesAsadullah Malik
ABSTRACT
Over the past two decades, significant attention has been focused on the development of advanced scheduling methods for repetitive/linear construction projects. Several approaches have been proposed by various research groups in order to solve specific problems in the scheduling of repetitive/linear construction projects such as high-rise buildings, bridges, pipelines, and highways. Some of these approaches represent milestones in the authors’ researches, and others provide a thorough solution implemented in computer software. This paper is a review of several articles related to this topic, which have been published in specialized journals since 1998. The solution methods for repetitive/linear scheduling problems are various, extending from simple graphical techniques to complex computational and optimization methods, such as genetic algorithms. The methods underlying the different solutions can be divided into three groups: exact, heuristic and metaheuristic. This paper presents an introduction into the different repetitive/linear scheduling problems, outlines the optimization methods proposed, classifies the different approach methods utilized and, finally, areas for future research are suggested.
Keywords: linear scheduling, construction management, repetitive units, optimization, genetic algorithms.
IRJET- Implementing Time and Cost Optimization in Commercial Building using P...IRJET Journal
This document discusses implementing time and cost optimization techniques in commercial building projects using Microsoft Project. It describes crashing activities by adding resources like workers and equipment to reduce durations, and using slack time and alternative materials to lower costs. The goal is to complete projects on time or under budget by analyzing the tradeoff between time and cost when crashing critical paths or using different building materials. Manual and software-based methods are evaluated for optimizing the schedule and minimizing total project duration and costs.
IRJET- A Study on Factors Affecting Estimation of Construction ProjectIRJET Journal
This document discusses factors that affect the accuracy of construction project cost estimation. It begins by outlining the importance of accurate cost estimation for construction projects. It then reviews previous literature that has identified various factors such as ineffective planning, design changes, weather, and material cost fluctuations.
The document describes the objectives of the study, which are to explore common cost estimation practices and identify significant cost estimation factors. It then provides more detail on the literature review, outlining several previous studies that examined factors like demand, time effects, use of rough set theory and neural networks in cost models, and factors relevant at different project stages.
The literature review discusses previous research identifying factors such as experience, project complexity, scope definition, cost data
Review of Hooke and Jeeves Direct Search Solution Method Analysis Applicable ...ijiert bestjournal
Role of optimization in engineering design is prominent one with the a dvent of computers. Optimization has become a part of computer aided design methodology. It is primarily being used in those design activities in which the goal is not only to achieve a feasible design,but als o a design objective. The paper reviews the optimization in detail followed by the literature review and b rief discussion of Hooks and Jeeves Method Analysis with an example.
Implementation of Line of Balance Method for Scheduling High-rise BuildingIJERA Editor
This document summarizes a study on implementing the Line of Balance (LOB) method for scheduling a high-rise building construction project. It begins with an introduction to LOB scheduling and its benefits for repetitive projects like high-rise buildings. It then outlines the methodology used, which includes collecting activity duration data, drawing LOB and histogram charts, analyzing the charts to determine total duration and resource needs, and crashing critical activities. The findings show crashing activities reduced the total project duration. Crew sizing was evaluated using histograms before and after crashing. It concludes LOB is useful for monitoring repetitive activities in high-rises and integrating it with critical path scheduling allows for effective activity crashing.
Cost Effective Construction Techniques By Stephen RaymentStephen Rayment UK
Stephen Rayment is the co-founder of Systech International, a company that focuses on providing cost effective construction techniques. Some secrets that Rayment emphasizes to reduce costs include developing strong supplier relationships, ensuring workers have the proper capabilities for tasks, planning future construction directions, and prioritizing customer service to meet needs. By focusing on these areas, Rayment has helped Systech International establish a reputation for delivering high quality construction projects on budget.
Resource levelling minimizes resource fluctuations by postpone the earliest start time (EST) of non-critical activities with corresponding floats. Float consumption for resource leveling may reduces the project completion probability. This paper presents a method to minimize the resource fluctuations with minimum impact of float consumption. A case study is presented to verify the validity and usability of the method.
The document discusses Project Evaluation Review Technique (PERT), a project management tool used to analyze tasks, time required, and critical paths. It describes various project management methodologies like PRINCE2, Agile, and Critical Path Method (CPM) that are suited for different types of projects. Finally, it discusses setting up an organizational structure and quality management process for a project.
The Automation of Critical Path Method using Machine Learning: A Conceptual S...Dr. Amarjeet Singh
This research aims to shed light on the use of machine learning in improving, developing and automating the critical path method, solving its problems, studying this effect and its dimensions, and discussing that from many aspects.
The research is divided into two theoretical and practical parts. The theoretical part is concerned with studying the critical path method and its advantages, problems and challenges, as well as studying machine learning and artificial intelligence and its dimensions, reviewing materials and sources related to this, and then presenting suggestions and future solutions based on this study. As for the practical section, it is a questionnaire that targeted a segment of engineers, in particular, and others who have sufficient experience in both the critical path method and machine learning, and seeking their opinions on both topics.
The result of the theoretical research was 14 theories or proposals that were presented based on the foregoing study. As for the practical questionnaire, a sample of 127 was taken. Through statistical analysis, the results were analyzed and discussed separately, and then a conclusion was drawn regarding them.
This document provides an overview of a quantitative study examining the contribution of Earned Value Management (EVM) to project success on external projects under contract. The study tested hypotheses about the relationship between EVM principles and project success, and whether that relationship differs for fixed-price versus cost-plus contracts. Key findings included that EVM principles positively predict project success, and that fixed-price contracts may benefit more from EVM than cost-plus contracts. The study contributes to understanding how EVM can improve project planning and control for different contract types.
STUDY AND ANALYSIS OF CONCRETE STRENGTH PARAMETERS USING VETIVER GRASS ASH AS...Vamsi Kovalam
The development of a new building material based on vetiver grass ash for use in the rural areas of the developing countries is experimentally investigated.
The properties of VGA were experimentally studied to consider the possibility of using VGA as a pozzolanic material.
Many developing countries are attempting to develop substitutes for cement from locally available raw materials like agricultural and industrial waste.
Fly ash ,rice husk ash and rice straw ash have been proven to be economical partial substitutes for cement
This document provides an overview of the RSMeans publication titled "Value Engineering in the Construction Industry". It includes a table of contents that outlines the various chapters in the book, which cover topics such as project budgeting, cost modeling, function analysis, life cycle costing, and case studies applying value engineering techniques. The document also provides brief descriptions of the content included in each chapter. It indicates that the book presents advances in value engineering since previous editions and includes an updated disk with additional value engineering tools and automated formats.
Cost Overrun Causes Related to the Design Phase in the Egyptian Construction ...World-Academic Journal
This document summarizes a research paper that aimed to identify and evaluate the most significant causes of cost overrun related to the design phase of construction projects in Egypt. Through a literature review and expert interviews, the researchers developed a list of potential cost overrun causes. They then conducted a survey with 101 industry professionals to quantitatively assess the frequency and impact of each cause. The results showed that the most important causes were design changes/variations and unrealistic construction time estimates. The degree of agreement between owners, contractors, architects, and project managers was also analyzed to identify any conflicting perspectives on the causes.
This research proposal aims to use concepts from chaos theory to predict project outcomes through aligning project and team objectives. The researcher will apply the concept of self-similarity in fractals to demonstrate how sustained alignment of project goals and personal goals of project managers and teams can optimize cost outcomes. The proposal provides background on definitions of project success, highlighting differences between project management success and overall project success. It also reviews literature on high failure rates of projects in various sectors such as IT, defense acquisition, and infrastructure. The researcher proposes investigating how chaos theory concepts can be applied to model project dynamics and determine basins of possible project outcomes.
The document discusses different project management techniques, focusing primarily on PERT (Program Evaluation and Review Technique). It provides an overview of PERT, including how to define tasks, estimate durations, calculate expected durations and variance/standard deviation for each task. It also discusses how to determine the critical path and calculate the probability of completing a project by a certain date. An example project is used to demonstrate how to populate a table with the necessary PERT calculations.
1. The document discusses cost estimation and management of construction projects. It outlines various factors that must be considered like project planning, scheduling, progress monitoring, time and cost estimation, cost management, change order management, and mitigating cost overruns.
2. Effective cost estimation requires considering construction methodology, resources, duration and feasibility. Time and cost have a strong relationship, as delays increase costs.
3. Cost management ensures a project is completed within budget through accurate budget preparation, crew sequencing, and cost optimization in scheduling. Change order management handles changes fairly.
This document summarizes a master's thesis that investigated implementing carpooling in new housing construction in Gothenburg, Sweden. The thesis questioned the city's parking ratio regulation. Through literature reviews, interviews, calculations, and a survey, the study found that carpooling could contribute to sustainability goals. However, the parking regulation requires special approval and offers no guarantees. Additionally, individual behaviors and societal views of car ownership complicate changing transportation choices. The thesis concluded the regulation lacks flexibility, economic rationality, and accurate demand estimation. It recommends a flexible, behavior-based approach that considers economics and potential travel impacts. Further research is needed to develop an improved regulation.
This document discusses planning and scheduling methods to optimize time and cost for the construction of a six-lane bridge with cast in situ and precast elements in Kolathur, Chennai. It reviews literature on scheduling techniques and identifies objectives like preparing a detailed schedule and cost estimate for both construction methods. The project methodology involves data collection, analysis, and comparing schedules and costs of cast in situ and precast construction to propose the best option. Schedules were prepared for both methods and costs were estimated using Excel. The research aims to minimize project duration and costs through optimized planning and use of advanced construction techniques.
A Case Study On Applying Lean Construction To ConcreteDawn Cook
The document discusses applying lean construction principles to concrete construction projects. It studies a concrete construction project to identify waste and proposes solutions. At the project level, lack of coordination among subcontractors caused schedule delays. The paper proposes using last planner concepts, linear scheduling, and graphic scheduling to improve communication and look-ahead planning. At the operation level, a systematic approach is applied to identify waste, redesign work procedures, and use 3D animation for employee training to reduce waste and resistance to changes.
An application of genetic algorithms to time cost-quality trade-off in constr...Alexander Decker
This document summarizes a research paper that develops an optimization model using genetic algorithms to solve the time-cost-quality trade-off problem in construction projects. The model aims to find the minimum cost for a construction project to meet certain quality levels within a given time limit. It does this by considering different activity execution modes and using genetic algorithms to efficiently explore the large solution space. The document provides background on optimization problems and techniques, an overview of the time-cost-quality trade-off problem and prior related research, and describes the objectives and approach of the developed genetic algorithms model.
Applicability of heuristic approach in planning and scheduling projectAlexander Decker
This document discusses applying heuristic approaches to planning and scheduling projects. It begins by defining projects and the importance of planning and scheduling resources. It then reviews different heuristic rules that have been used and compares their effectiveness. The document proposes using earliest finish time and total float as a heuristic rule for this work. It develops a mathematical formulation to calculate resource ceilings and project cash flows. The formulation is used in a computer program to allocate resources with the goal of minimizing resource utilization while meeting deadlines. The program calculates resource usage, utilization, weighted utilization and a "constraining index" to identify the most constrained resources.
Time Cost Trade off Optimization Using Harmony Search and Monte-Carlo Method Mohammad Lemar ZALMAİ
Project cost and project duration are main factors in construction management. In real-life projects, both the trade-off between the project cost and the Project completion time, and the uncertainty of the environment are considerable aspects for decision-makers. Moreover, in some projects, activity durations show their complexity with time-dependence as well as randomness. Time cost trade off problem have been solved by using vast of methods such as genetic algorithms, particle swarm optimization. Most of these studies considered deterministic project values and includes CPM calculations for fitness value calculation. However most of construction projects are stochastic processes. In this paper, a stochastic time–cost trade-off problem is introduced. This study takes into account that activity duration and cost are uncertain variables. this study differs from other studies that for each fitness value calculation. The proposed model is dealt with an intelligent algorithm combining stochastic simulation and Harmony search, where stochastic simulation technique is employed to estimate random functions and Harmony search is designed to search optimal schedules under different decision-making criteria. Beside this Monte Carlo simulation is made for fitness value calculation in order to make more realistic optimization. Finally, some numerical experiments are given to illustrate the algorithm effectiveness.
Cost Effective Methods in Construction Engineeringcivejjour
The economic impact of construction cost overrun is a possible loss of the economic justification for the
project. The financial impact of a cost overrun results in demand for construction investment credits.
Therefore reliable estimates of construction cost are an important aspect to the contemporary construction
companies especially during the conceptual phase of lifecycle management. In this paper a cost-effective
analysis is done using one of the cost effective construction technique called Rat Trap Bond versus Flemish
bond and when estimated with CPWD 2012 schedule of rates it is proved that Low cost techniques such as
rat trap bond provides better cost effectiveness as compared to conventional Flemish bond construction
method.
Cost Effective Methods in Construction Engineeringcivejjour
The economic impact of construction cost overrun is a possible loss of the economic justification for the project. The financial impact of a cost overrun results in demand for construction investment credits. Therefore reliable estimates of construction cost are an important aspect to the contemporary construction companies especially during the conceptual phase of lifecycle management. In this paper a cost-effective analysis is done using one of the cost effective construction technique called Rat Trap Bond versus Flemish bond and when estimated with CPWD 2012 schedule of rates it is proved that Low cost techniques such as rat trap bond provides better cost effectiveness as compared to conventional Flemish bond construction method.
An Integrated BIM System To Track The Time And Cost Of Construction Projects ...Nat Rice
The document summarizes a research article that proposes an integrated time and cost management system (ITCMS) for construction projects. The ITCMS uses earned value management (EVM) within a building information modeling (BIM) virtual environment during project planning and construction. The system consists of four modules - visualization, time/cost estimating, scheduling, and EVM. It allows construction professionals to synchronize the building model with time/cost parameters and optimize it through clash detection early on. The researchers demonstrate the ITCMS validity through a case study project. The system is intended to improve project performance and budget/schedule success for construction managers.
Project Scheduling: Survey and Research PotentialsEditor IJCATR
project scheduling is very critical topic in project management. Resource constrained project scheduling problem (RCPSP) consists of activities that must be scheduled based on dependencies relationships and priorities of activities. In the recent years there have been many survey papers around the area of project scheduling, as many researchers developed both exact and heuristic scheduling schemes. This paper give an over view around the resource constrained project scheduling problem (RCPSP).
This document discusses construction project management and cost reduction techniques. It explains that construction project management aims to control time, cost, and quality of large, complex construction projects. However, many projects experience issues like cost overruns, delays, and conflicts. The document then outlines various cost reduction techniques that can be used, including value engineering, material management, budgetary control, and cost optimization methods. It emphasizes applying these techniques through a multidisciplinary approach to improve value and economy without compromising quality or requirements.
STRATEGIC COST MANAGEMENT FOR CONSTRUCTION PROJECT SUCCESS: A SYSTEMATIC STUDYcivejjour
Large construction projects are inherently complex and dynamic. Many projects start with good ideas, huge investments and great efforts. However, most of them do not achieve much success. A major contribution to unsuccessful projects is the lack of understanding on scope, time, cost and quality. Projects as powerful strategic weapons when initiated create economic value and competitive advantage. The objective of the research is to explicitly declare the scope of the research to by considering only the scope, time, cost and quality as process success parameters and how specifically the cost element would influence the project success when all other elements or factors other than cost are represented in terms of cost factor along with the contract conditions as basic rules or constraints that drive the strategic cost based on applying the CRASP methodology concept. The concept of benchmarking would provide right meaning of project success when allowing to properly distributing the meaning of customer profitability to the project providers (project owner and contractors).
STRATEGIC COST MANAGEMENT FOR CONSTRUCTION PROJECT SUCCESS: A SYSTEMATIC STUDYcivejjour
Large construction projects are inherently complex and dynamic. Many projects start with good ideas, huge investments and great efforts. However, most of them do not achieve much success. A major contribution to unsuccessful projects is the lack of understanding on scope, time, cost and quality. Projects
as powerful strategic weapons when initiated create economic value and competitive advantage.
Planning is a guideline in implementing the project so that development can be
implemented in accordance with the time and cost planned. Control discrepancy
between initial plan and realization that exists in implementation project required a
project management, therefore required optimization analysis of project duration, so
it can be known how long a project is completed and look for the possibility of project
acceleration implementation by Project Evaluation and Review Technique (PERT)
and Critical Path Method (CPM) or critical path method. This research aims to apply
Project Evaluation and Review Technique (PERT) and Critical Project Management
(CPM) methods to find optimize solutions and control the performance of time and
cost in project scheduling. The research method used case study method at hospital
project in Bogor District, Indonesia, by collecting data direct observation and
interview results at contractor. Based on these data, create a schedule by using PERT
and CPM methods, which will be measured performance of time performance and
project cost which is expected to overcome the problem of controlling and completion
of project. The results of this study, using PERT and CPM methods proved to optimize
the project. Based on calculation by PERT method reduce duration of work: 12 days
(13, 18%). Based on calculation by CPM method reduce duration of work: 31 days
(34, 06%) but direct cost increase 112.208,300, - rupiahs (0, 25%).
Towards Innovate Methods of Construction Cost Management and Controlcivejjour
Project cost is one of the three main challenges for the construction manager, where the success of a
project is judged by meeting the criteria of cost with budget, schedule on time, and quality as specified by
the owner. Many projects experience extensive delays and thereby exceed initial time and cost estimate.
Available information, good estimating practice and experienced personnel are some of the factors found
to have considerable impact on estimation accuracy. The successful execution of construction projects and
keeping them within estimated cost and prescribed schedules depend on a methodology that requires sound
engineering judgment. So the research aim is to conduct research study and process of exploring the
existing model related to above three types of estimate and their contribution to civil engineering cost
management and control especially getting motivated with the verification and validation component of
CRASP methodology. The objective of this paper or scope of this research in this paper is to conduct
literature study and review towards exploring innovative techniques such as Artificial Intelligence
Techniques or Expert System Techniques available and applicable to make decision making or decision
support regarding construction cost management and control at three levels: (i) before the actual civil
engineering project design begins (ii) after detailed design but before execution and (iii) during project
execution
This document presents a simulation model for evaluating order acceptance strategies that consider man-hour (MH) constraints in engineering, procurement, and construction (EPC) projects. The model simulates competitive bidding situations and calculates expected revenues, costs, and profits over multiple periods based on the volume of accepted orders and MH available for cost estimation and project execution. Simulation results show that a strategy maintaining an appropriate balance of MH for cost estimation and project execution can improve total expected profit over the long run under varying order volumes from competitive bidding.
This document discusses construction project management. It begins with an introduction to project management and its goals of completing projects on time, within budget and to quality standards. It then outlines the typical steps in project management including initiation, planning, construction and closeout. It discusses working with project teams and techniques for scheduling like Gantt charts. The document also covers project budgeting, planning tools like Building Information Modeling (BIM), and concludes with case studies of large construction projects like Burj Khalifa that achieved tight schedules through use of new technologies and project management best practices.
Literature Review in Project Scheduling TechniquesObi-Ugbo Alex
This document provides a literature review of 33 journal articles on project scheduling techniques from 1994 to 2016. It summarizes various approaches that have been developed to overcome limitations of traditional scheduling tools like CPM and PERT in dealing with stochastic environments, resource constraints, and repetitive projects. The reviewed research aims to reduce project duration, solve time and resource constraints, and address issues in job shop scheduling. New methods discussed include dependency structure matrix, fuzzy critical path analysis, stochastic project scheduling simulation, line of balance for repetitive projects, and approaches using resource dependencies, discounted cash flows, and SAT solvers to deal with resource-constrained project scheduling problems.
Efficient Planning Scheduling and Delay Analysis of Residential ProjectIJERA Editor
Planning and scheduling have become an essential part of any project for the timely and economical completion of the project. A proper construction schedule can be used for different purposes. By using construction schedule to predict project completion, contractors can adjust crew size, shifts or equipment to speed or slow the progress. All the construction projects will vary from each other in size. All the projects have time constraint. Delay in completion of project will increase the overall cost of the project. Small projects can be managed efficiently manually; whereas large projects are not so large projects can be better handled by the use of computers. Many types of software are available with the help of which project management can be done easily. Large quantities of different kinds of resources are also required for execution and the risk is more in the case of projects. So planning and scheduling of activities for construction of big projects is essential. In this study, an effort is made in planning, scheduling and delay analysis updating of various activities, which is done by using MS Project and MS Excel software, manpower of each activity is determined and allocation is done using the software. Labor requirement for each activity is calculated from standards obtained from site. An updated schedule, which helps to finish the project well in time with optimum resources and update helps in delay analysis, is under the scope of this study.
This study uses Monte Carlo simulations to analyze the impact of delays in engineering, procurement, and construction activities on the schedule of three sample onshore oil and gas EPC projects. The simulations found that engineering activities have up to 10 times greater impact on the overall project schedule than procurement or construction activities. Specifically, piping design activities were found to have the greatest impact. Based on these findings, the study presents a six-step design schedule management process to minimize delays. The process includes milestone management, drawing status management, engineering productivity management, interface management, management of major vendor documents, and work front management.
Similar to Time-cost optimization using harmony search algorithm in construction projects (20)
Implementation of Building Information Modelling in Turkish Government Sector...Mohammad Lemar ZALMAİ
In recent years, the Building Information Modelling (BIM) approach has been developed expeditiously. As people see the benefits of this new approach, it has begun to be used widely in construction projects and some countries made it mandatory to get more benefits from it.
To promote the implementation of BIM in construction projects, it’ll be helpful to get some relevant information from surveys and interviews.
The purpose of this study is to research the current adoption and implementation of BIM in public projects in Turkey. This study specified the challenges of BIM implementation in Turkey and proposed some solutions to overcome them.
In this context, the challenges for BIM implementation and the factors that affect the BIM usage are determined based on previous academic researches and expert opinions by conducting interviews and questionnaire surveys.
Several methods are used to process information in order to obtain weights of different factors to make BIM become widespread in Turkey.
This study concluded interviews' and questionnaire surveys' outcomes and proposed some suggestions to promote the implementation of BIM in Turkey. We believe research findings will be a good reference for boosting BIM implementation in Turkey.
Performance Evaluation of Construction Projects by EVM Method, Using Primaver...Mohammad Lemar ZALMAİ
Most of the construction projects are exposed to time and cost overruns due to various factors and this is a major problem. As a solution to this, the Earned Value Management (EVM) method is considered. EVM is a powerful and well-known method used in monitoring and controlling the project. EVM gives an early indication that either project is delayed or not and the project is either over budget or under budget at any particular day by tracking it. Thus, it helps to improve the management control system of a construction project, to detect and control the problems in potential risk areas and to suggest the importance and purpose of monitoring the construction work.
This paper explains the main parameters of the EVM system involved in the calculation of time and cost for construction projects. In this study, the Primavera P6 software is used to deals with the project monitoring process of a seven-storeyed (G+6) faculty building whose construction is in progress at Istanbul, Turkey. A comparison between the planned progress of construction activities and actual progress is performed and the analysis results are interpreted. This case study justifies the benefits of using EVM for project cash flow analysis and forecasting.
Determining costs of construction errors, based on fuzzy logic systems ipcmc2...Mohammad Lemar ZALMAİ
In construction projects, construction errors affect negatively to the production, that influences the overall of the project in both time and budget. Generally, construction companies could not estimate this kind of errors during the bidding process. In this case, these companies did not consider important issues on the budget of the contract, and in the contracting period, project participants assumed that the project would be executed as it scheduled and designed. During the project, different construction processes’ costs are higher than estimated values due to construction errors.
The errors that were recognized during the construction process cause time and financial losses, on the other hand, the errors that were noticed after the project’s termination cause repair and correction costs. Moreover, the company may gain a bad reputation in the sector.
The key points of this study are to analyze project costs by considering construction errors and re-construction costs due to labor errors by using fuzzy interpretation mechanism. This methodology is applied to a residential construction project. With using of this methodology, forthcoming extra costs related to construction errors can be estimated. And some precautions can be taken for further legal conflicts between parties.
Determining Costs of Construction Errors, Based on Fuzzy Logic SystemsMohammad Lemar ZALMAİ
In construction projects, construction errors affect negatively to the production, that influences the overall of the project in both time and budget. Generally, construction companies could not estimate this kind of errors during the bidding process. In this case, these companies did not consider important issues on the budget of the contract, and in the contracting period, project participants assumed that the project would be executed as it scheduled and designed. During the project, different construction processes’ costs are higher than estimated values due to construction errors.
The errors that were recognized during the construction process cause time and financial losses, on the other hand, the errors that were noticed after the project’s termination cause repair and correction costs. Moreover, the company may gain a bad reputation in the sector.
The key points of this study are to analyze project costs by considering construction errors and re-construction costs due to labor errors by using fuzzy interpretation mechanism. This methodology is applied to a residential construction project. With using of this methodology, forthcoming extra costs related to construction errors can be estimated. And some precautions can be taken for further legal conflicts between parties.
Time cost trade off optimization using harmony search and Monte-Carlo MethodMohammad Lemar ZALMAİ
This document summarizes a study that uses harmony search optimization and Monte Carlo simulation to optimize the time-cost tradeoff for construction projects with uncertain activity durations. Markov chains are used to model crew performance variability over time. The harmony search algorithm evaluates solutions by running Monte Carlo simulations to obtain probabilistic time and cost distributions, which are compared using a Kolmogorov-Smirnov test to determine statistical dominance between solutions. The approach is demonstrated on a sample project network problem.
Abstract—In recent years, the Building Information Modeling
(BIM) approach has been developed expeditiously. As people see the benefits of this approach, it has begun to be used widely in construction projects and some countries made it mandatory to get more benefits from it. To promote the implementation of BIM in construction projects, it will be helpful to get some relevant information from surveys and interviews. The purpose of this study is to research the current adoption and implementation of BIM in public projects in Turkey. This study specified the challenges of BIM implementation in Turkey and proposed some solutions to overcome them. In this context, the challenges for BIM implementation and the factors that affect the BIM usage are determined based on previous academic researches and expert opinions by conducting interviews and questionnaire surveys. Several methods are used to process
information in order to obtain weights of different factors to make BIM widespread in Turkey. This study concluded interviews' and questionnaire surveys' outcomes and proposed some suggestions to promote the implementation of BIM in Turkey. We believe research findings will be a good reference for boosting BIM implementation in Turkey.
Performance Evaluation of Construction Projects by EVM Method, Using Primaver...Mohammad Lemar ZALMAİ
Abstract
Most of the construction projects are exposed to time and cost overruns due to various factors and this is a major problem. As a solution to this, the Earned Value Management (EVM) method is considered. EVM is a powerful and well-known method used in monitoring and controlling the project. EVM gives an early indication that either project is delayed or not and the project is either over budget or under budget at any particular day by tracking it. Thus, it helps to improve the management control system of a construction project, to detect and control the problems in potential risk areas and to suggest the importance and purpose of monitoring the construction work. This paper explains the main parameters of the EVM system involved in the calculation of time and cost for construction projects. In this study, the Primavera P6 software is used to deals with the
project monitoring process of a seven-storey (G+6) faculty building whose construction is in progress at Istanbul, Turkey. A comparison between the planned progress of construction activities and actual progress is performed and the analysis results are interpreted. This case study justifies the benefits of using EVM for project cash flow analysis and forecasting.
Keywords: construction cost management, construction planning, earned value management (EVM), Primavera p6, project management, project scheduling.
Bu çalışma kapsamında bir yerleşim planı verilen şehrin su ihtiyacını karşılamak için isale hattı tasarımı yapılmıştır.
Yerleşim biriminde 110 konut, 6 park, 3 alışveriş merkezi, 2 fabrika,2 tarla ve 1 okul bulunuyor.
Bir Kamu İnşaat Projesinde CPM Uygulamamasından Dolayı Ortaya Çıkan Problemle...Mohammad Lemar ZALMAİ
İnşaat Sektöründe CPM in iki değişik uygulama alanı vardır. Birincisi, proje öncesi faaliyetlerin süresel olarak planlama ve proje gidişatı hakkında tahmin yürütme, bunun yanında projenin geçmişine dönük bir kara kutu görevi görmektedir. Dünyadaki inşaat sektöründe sıklıkla kullanılmakta iken Türkiye’de halen yeteri kadar yaygın bir şekilde uygulanmamaktadır. Ve bu durum gerek proje esnasında veya proje bitiminde yaşanan uyuşmazlıklarda bu eksiklik kendini belli etmektedir. Bu çalışmada bir kamu binası inşaatı sürecinde CPM uygulaması ve uygulama esnasında CPM in proje gidişatına ne kattığı ve yeterli derecede kullanılmaması durumunda ne gibi problemlere yol açtığı incelenmiştir
Bir Kamu İnşaat Projesinde CPM Uygulamamasından Dolayı Ortaya Çıkan Problemle...Mohammad Lemar ZALMAİ
İnşaat Sektöründe CPM in iki değişik uygulama alanı vardır. Birincisi, proje öncesi faaliyetlerin süresel olarak planlama ve proje gidişatı hakkında tahmin yürütme, bunun yanında projenin geçmişine dönük bir kara kutu görevi görmektedir. Dünyadaki inşaat sektöründe sıklıkla kullanılmakta iken Türkiye’de halen yeteri kadar yaygın bir şekilde uygulanmamaktadır. Ve bu durum gerek proje esnasında veya proje bitiminde yaşanan uyuşmazlıklarda bu eksiklik kendini belli etmektedir. Bu çalışmada bir kamu binası inşaatı sürecinde CPM uygulaması ve uygulama esnasında CPM in proje gidişatına ne kattığı ve yeterli derecede kullanılmaması durumunda ne gibi problemlere yol açtığı incelenmiştir
AFGANİSTAN'ın kısaca tanıtım sunumu/ briefly introduction of AFGHANISTAN in T...Mohammad Lemar ZALMAİ
Afganistan’ın Bayrağı, coğrafik özellikleri
Afganistanın Tarihi ve Yönetim şekli
Önemli Afgan bilim ve siyasi şahsiyetleri ve ünlüler
Afganistanın Kültürü
Afganistan ile Türkiye arasındaki ilişkileri
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSIJNSA Journal
The smart irrigation system represents an innovative approach to optimize water usage in agricultural and landscaping practices. The integration of cutting-edge technologies, including sensors, actuators, and data analysis, empowers this system to provide accurate monitoring and control of irrigation processes by leveraging real-time environmental conditions. The main objective of a smart irrigation system is to optimize water efficiency, minimize expenses, and foster the adoption of sustainable water management methods. This paper conducts a systematic risk assessment by exploring the key components/assets and their functionalities in the smart irrigation system. The crucial role of sensors in gathering data on soil moisture, weather patterns, and plant well-being is emphasized in this system. These sensors enable intelligent decision-making in irrigation scheduling and water distribution, leading to enhanced water efficiency and sustainable water management practices. Actuators enable automated control of irrigation devices, ensuring precise and targeted water delivery to plants. Additionally, the paper addresses the potential threat and vulnerabilities associated with smart irrigation systems. It discusses limitations of the system, such as power constraints and computational capabilities, and calculates the potential security risks. The paper suggests possible risk treatment methods for effective secure system operation. In conclusion, the paper emphasizes the significant benefits of implementing smart irrigation systems, including improved water conservation, increased crop yield, and reduced environmental impact. Additionally, based on the security analysis conducted, the paper recommends the implementation of countermeasures and security approaches to address vulnerabilities and ensure the integrity and reliability of the system. By incorporating these measures, smart irrigation technology can revolutionize water management practices in agriculture, promoting sustainability, resource efficiency, and safeguarding against potential security threats.
Low power architecture of logic gates using adiabatic techniquesnooriasukmaningtyas
The growing significance of portable systems to limit power consumption in ultra-large-scale-integration chips of very high density, has recently led to rapid and inventive progresses in low-power design. The most effective technique is adiabatic logic circuit design in energy-efficient hardware. This paper presents two adiabatic approaches for the design of low power circuits, modified positive feedback adiabatic logic (modified PFAL) and the other is direct current diode based positive feedback adiabatic logic (DC-DB PFAL). Logic gates are the preliminary components in any digital circuit design. By improving the performance of basic gates, one can improvise the whole system performance. In this paper proposed circuit design of the low power architecture of OR/NOR, AND/NAND, and XOR/XNOR gates are presented using the said approaches and their results are analyzed for powerdissipation, delay, power-delay-product and rise time and compared with the other adiabatic techniques along with the conventional complementary metal oxide semiconductor (CMOS) designs reported in the literature. It has been found that the designs with DC-DB PFAL technique outperform with the percentage improvement of 65% for NOR gate and 7% for NAND gate and 34% for XNOR gate over the modified PFAL techniques at 10 MHz respectively.
International Conference on NLP, Artificial Intelligence, Machine Learning an...gerogepatton
International Conference on NLP, Artificial Intelligence, Machine Learning and Applications (NLAIM 2024) offers a premier global platform for exchanging insights and findings in the theory, methodology, and applications of NLP, Artificial Intelligence, Machine Learning, and their applications. The conference seeks substantial contributions across all key domains of NLP, Artificial Intelligence, Machine Learning, and their practical applications, aiming to foster both theoretical advancements and real-world implementations. With a focus on facilitating collaboration between researchers and practitioners from academia and industry, the conference serves as a nexus for sharing the latest developments in the field.
Time-cost optimization using harmony search algorithm in construction projects
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Time-cost optimization using harmony search algorithm in construction
projects
Optimización del costo del tiempo, utilizando el algoritmo de búsqueda de armonía en proyectos
de construcción
Mohammad Lemar Zalmai (Main Author)
Istanbul University-Cerrahpasa, Department of Civil Engineering
Istanbul, 34320 (Turkey)
lemar_zalmai07@hotmail.com
Cemil Akcay (Corresponding Author)
Istanbul University, Faculty of Architecture,
Istanbul, 34116 (Turkey)
cakcay@istanbul.edu.tr
Ekrem Manisali
Nisantasi University, Department of Civil Engineering
Istanbul, 34398 (Turkey)
ekmanisa@istanbul.edu.tr
Manuscript Code: 1153
Date of Acceptance/Reception: 05.07.2019/19.07.2018
DOI: 10.7764/RDLC.18.2.226
Abstract
In construction projects, the relationship between project cost and duration, which is one of the main factors of the project, are considered the
parameters decision-makers. When a construction schedule is planned by the planners, additional resources are allocated to shorten the project
duration considering the completion time and cost of the activities so that the most suitable construction schedule is prepared by providing a trade-
off between project duration and total cost. In the case of time-cost trade-off problems, the total cost of the project is determined by summing each
activities’ cost by adding indirect costs. Moreover, total project duration is determined by obtaining total project duration after CPM (Critical Path
Method) calculations. Obtaining optimum duration and costs is such a problematic issue with using conventional methods and common software
packages. These techniques consider deterministic project values and include CPM calculations for fitness value calculation. Moreover, current studies
defined alternatives as non-variable discrete values. However, construction projects are dynamic processes, and quantities are prone to be changed
related to project size. In this study, time-cost trade-off optimization is performed by using harmony search method with introducing different
implementation that can be more easily used for different projects. The model is implemented in a real construction project, and the conclusions are
interpreted.
Keywords: Construction sector, CPM (Critical Path Method), multi-objective optimization, harmony search method, time-cost trade-off.
Resumen
En los proyectos de construcción, la relación entre el costo y la duración del proyecto, que es uno de los principales factores del proyecto, se
consideran los parámetros que toman las decisiones. Cuando los planificadores planifican un cronograma de construcción, se asignan recursos
adicionales para acortar la duración del proyecto considerando el tiempo de finalización y el costo de las actividades, de modo que el cronograma de
construcción más adecuado se prepare al proporcionar un intercambio entre la duración del proyecto y el costo total. En el caso de problemas de
compensación de tiempo y costo, el costo total del proyecto se determina sumando el costo de cada actividad al agregar los costos indirectos. Además,
la duración total del proyecto se determina al obtener la duración total del proyecto después de los cálculos de CPM (Método de ruta crítica). Obtener
una duración y costos óptimos es un problema tan problemático con el uso de métodos convencionales y paquetes de software comunes. Estas
técnicas consideran los valores deterministas del proyecto e incluyen cálculos de CPM para el cálculo del valor de aptitud. Además, los estudios
actuales definieron alternativas como valores discretos no variables. Sin embargo, los proyectos de construcción son procesos dinámicos, y las
cantidades son propensas a cambiar en relación con el tamaño del proyecto. En este estudio, la optimización de la compensación de tiempo y costo
se realiza utilizando el método de búsqueda de armonía con la introducción de diferentes implementaciones que se pueden usar más fácilmente para
diferentes proyectos. El modelo se implementa en un proyecto de construcción real, y se interpretan las conclusiones.
Palabras clave: Sector de la construcción, CPM (Método de ruta crítica), optimización multiobjetivo, método de búsqueda de armonía, compromiso
tiempo-costo.
Introduction
Trade-offs frequently appear in the decision-making process in construction management. Duration and costs are
considered as two primary variables, and in most cases, they are inversely related. So, in the scheduling phase, the time-
cost trade-off (TCTO) problem is appeared and can affect the project in various ways. For instance, in most contracts,
the contractor has to satisfy various items in means of durations, quality and time. So, time-cost trade-off problems are
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considered as one of the great significant topics in project delivery and attention are paid by project managers. Time
and cost as two critical objectives of construction project management are not independent but inversely related.
Generally, time-cost trade-off appeared as a result of construction speeding up by changing crew-size, adding overtime
and transition to other construction techniques (Feng, & Liu, 1997; Hegazy, 1999). In general, determining time-cost
trade-off is a difficult issue because it may depend on the project’s inherent characteristics. While ongoing of the project,
planners generally choose to crash critical activities to make project completed earlier to avoid delays, and also to gain
opportunity costs by completing before finishing the project before the determined time. On the other hand, non-critical
activities are chosen to be expanded to decrease in total cost (Siemens, 1971). Time-cost trade-off analysis is important
parameters in the planning and control of construction projects; different resources and technologies play an active
role in determining the duration and cost of the project, including appropriate workforce, equipment, and building
methodologies. One of the most important concepts in today's construction sector is the effect of total finance when
construction activities are done at different speeds. In this study, the optimal time-cost pairs of the project were
obtained according to the HS model which was prepared to take the time and cost into consideration by determining
the application methods and technologies of the activities in a project.
The reduction of the time and cost of construction projects is very important in today's market-oriented economy. The
relationship between time and cost is called time-cost trade-off decisions, and this concept is being extensively explored
in the construction management literature. The time-cost trade-off, as a crucial management tool, deals with the
compromise between total cost and project duration, when it is not possible to plan a project within a certain time and
exceeds one of the critical path method limitations.
In time-cost trade-off problems that can be solved by many different methods, the relationship between time and cost
is first made as "continuous." However, due to the discrete values of the resources used, the problem is being used in
practice as discrete time-cost trade-off problems by evaluating discrete data sets. As a classical method, a mixed integer
programming is applied to many time-cost trade-offs applications. While classical methods to find the exact solution
and heuristic methods to which the exact or approximate result is targeted, apply to time-cost trade-off problems
(Sonmez, & Bettemir, 2012). The most traditional form of time-cost relationship is expressed as linear. Kelley (1961),
Siemens (1971), Salem & Elmaghraby (1994), Hendrickson & Au (1989), Tareghian & Taheri (2006), and Chen & Tsai
(2011), apply linear approaches for time-cost problems. These methods can only optimize single-objective problems.
However, if the optimization of time and cost is requested concurrently, these methods fail. The aim of TCTO is to find
the best alternative solution by providing the optimal total duration and cost of the project. TCTO problem is very
difficult to solve with traditional mathematical methods. Because time-cost trade-off problem includes so complicated
formulation of mathematical structure and, thus it is very difficult to gain optimal solutions (De et al., 1997). Accordingly,
the researchers try to find heuristic and metaheuristic methods to solve this problem and obtain the best solutions. The
metaheuristic algorithms are outstanding methods in this field due to their flexible and adaptable structure. In this
regard, metaheuristic methods have been developed to achieve the optimum or near-optimal result when classical
methods are inadequate.
TCTO problem has been widely studied and many different algorithms have been suggested by many researchers in the
literature. In the last decade, there are works where different methods have been used to solve the time-cost trade-off
problem. Some of these studies related to TCTO problem solving with metaheuristic algorithms are as follows: Geem
(2010a) applied a Harmony Search (HS) algorithm to solve time-cost trade-off problems. The objective is to minimize
total cost, which includes direct and indirect cost. Also, Jian-Hong et al. (2017) propose time-cost trade-off of project
based on the improved harmony search algorithm. Prascevic & Prascevic (2014) applied the PSO method for solving
time-cost optimization and developed a proper computer program for this purpose. Ashuri & Tavakolan (2015)
proposed the Pareto front optimization of resources together with the time and cost and presented a Shuffled Frog
Leaping Algorithm. Aminbakhsh & Sonmez (2016) presented discrete particle swarm optimization method for the large-
scale discrete time-cost trade-off problem. He, He, Liu, & Wang (2017) proposed Variable Neighbourhood Search and
Tabu Search for TCTO problem to minimize the maximal cash flow gap. Tran & Long (2018) presented Project scheduling
with time, cost and risk trade-off using adaptive multiple objective differential evolution. They applied an algorithm
named as adaptive multiple objective differential evolution (AMODE) for producing optimized schedules considering
time, cost and risk simultaneously. Albayrak & Ozdemir (2018) proposed a novel hybrid method based on FA and PSO
for time-cost trade-off in construction. In this method, the problem is modeled with various execution modes to select
the optimal one for each activity.
In this study, we applied HS on solving TCTO problem on a real construction project. In the present study, the techniques
and alternative applications for excavation and foundation activities of a construction project were investigated. In this
respect, similar work items were drawn for each activity, based on unit price analysis. Later on, from the relevant work
items of their activities, it was aimed to reach the most suitable time-cost pairs (Pareto solution set) of the project with
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HS method. Because alternative solutions to the problem are not ignored, the most appropriate time-cost pair can be
selected from the proposed solution set according to the duration or cost constraint of the project. Therefore, it is
emphasized that the implementation project should present the Pareto results in detail, taking into account the
different applications of the activities in a project, and emphasized that alternative solutions should not be ignored.
Each alternative solution includes different construction production technique. In Pareto analysis, there may be
numerous alternatives can be obtained instead of only one optimum solution. So that different alternative production
techniques are not neglected in order to optimize both project duration and cost.
Description of the problem
In literature, only generic applications were given. For instance, discrete time-cost variables have been used and
analyzed. However, in the construction sector, the variables are project-dependent and can depend on project-size and
economical conditions. In order to apply to the construction sector, real projects data needs to be used and applied in
a more realistic style. For instance, we used quantities and unit costs directly to display the result in a more practical
way. Rather than a case study, this paper applies time-cost trade-off methodology in a more realistic way. The HS
algorithm can solve various types of problem very easily and effectively because complex calculations are not required.
The HS can use discrete, continuous relationships and linear and nonlinear functions can be implemented in it (Peraza,
2015). Different kinds of algorithms can be merged with HS. Such as, HS has "stochastic-derivative" which makes this
algorithm works well for combinatorial optimization problem (Geem, 2008). Thus, this study used because of its
simplicity and versatility. Due to its simplicity and versatility, the HS algorithm is convenient for this study.
State of the Art Review on optimization and harmony search algorithm
Categorization of optimization algorithms
Optimization problems are generally considered as deterministic and stochastic in two main categories (Table 1). In the
deterministic approach, while solutions are made by classical methods taking into account the known parameters, the
variables that may occur in the design are not considered, whereas the variables in the stochastic approach are taken
into account. Current techniques for solving the construction time-cost concession problem; heuristic scanning and
mathematical programming.
Table 1. Categorization of optimization algorithms Source: Yang (2010).
Deterministic Stochastic
Linear programming Heuristic
Non-linear programming Metaheuristic*
Gradient-based
Free of gradient
*Population-based, Trajectory-based.
In the mathematical programming method, time-cost trade-off problems are transformed into mathematical models
and solved by linear programming, integer programming or dynamic programming methods. The mathematical
programming problem consists of optimizing a goal function under certain constraints.
Heuristic methods are algorithms based on natural phenomena to accomplish any purpose or goal, and these algorithms
generally provide good solutions but do not consider optimality. For this reason, the exact solution is not obtained
because the heuristic algorithms have the convergence feature, so a solution is obtained near the exact solution.
Metaheuristic methods aim to combine basic heuristic methods that will enable the search for solution space efficiently.
In this respect, these methods are general purpose heuristics designed to guide probing-specific intuitions to perform
searches in regions of high-quality solutions of search space (Stützle, & Dorigo, 2004). Top-heuristic algorithms; is a
decision mechanism that works on heuristic algorithms. When three different methods are used for a problem, and
each of these methods is predicted to be heuristic algorithms with advantages for different purposes, it is decided by
the metaheuristic algorithm that the heuristic methods are selected.
The most preferred and known heuristic methods in engineering problems; Genetic algorithm (GA), Particle swarm
optimization (PSO), Ant colony optimization (ACO), Harmony search (HS), Artificial bee colony (ABC), Simulated
annealing (SA) and Firefly algorithms (FA). Currently, more than one method has been developed for the solution and
is optimized according to the problems. However, the possibility of choosing between more than one solution methods
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for a problem is achieved by using the metaheuristic method. The most heuristic algorithms on which statistical data
are based are often run with the most successful ones selected from among the algorithms.
Harmony search method
Harmony search (HS) is a meta-heuristic algorithm developed by Geem et al. (2001) which is inspired by the natural
musical performance process that occurs when a musician searches for a better state of harmony. The algorithm is
inspired by melodic harmony that objects to find convenient sounds to match with the musical clef. There are different
musicians and instruments that sound at the same time. Similar to the improvisation process of musicians to find the
convenient tone, the algorithm finds optimum trials with meta-heuristic search technique.
Harmony Search (HS) is a population-based meta-heuristic algorithm which has gained great results in the field of
combinatorial optimization (Geem, 2001). As HS is a population-based algorithm, it maintains a set of solutions in
Harmony Memory (HM). At every iteration, an estimation of the optimal solution is obtained by a set of optimization
parameters which applies to the HM to produce a new harmony vector every time. Figure 1 illustrates the flow diagram
of the HS algorithm, which can be summarized in four steps: (I) initialization of the HM; (II) improvisation of a new
harmony; (III) inclusion of the newly generated harmony in the HM provided that its fitness improves the worst fitness
value in the previous HM; and (IV) returning to step (II) until a termination criteria (e.g. maximum number of iterations
or fitness stall) is satisfied.
The metaheuristic algorithms have a strong dependency on the shape of the solution space drawn by the metric
function. Therefore, we cannot say to any meta-heuristic algorithm that is better than others according to convergence
and behavior in a general manner. But instead, needs to be evaluated by focusing on a certain problem with its
constraints and mathematical formulation. Thus, even though a globally optimal algorithm that shows the best
performance in all optimization schemes does not exist in line with the statements of the so-called No Free Lunch
Theorem (Wolpert & Macready, 1997), the HS algorithm still has demonstrated in practice a great potential and
efficiency in a wide range of real applications compare to other meta-heuristic methods. HS has a similar structure to
other existing population-based metaheuristic algorithms. But HS contains some significant features that make it widely
used in the literature. HS generate a new vector after considering all existing vectors instead of considering only two
(parents) as in the genetic algorithm, and it does not need to initial values of decision variables (Geem et al., 2001). Also,
instead of a gradient search, the HS algorithm uses a stochastic random search that is based on the harmony memory
considering rate (HMCR) and the pitch adjusting rate (PAR) so it does not need to any derivative information (Geem,
2010b). These features help HS in increasing flexibility and in finding better solutions, so it widely used in the literature.
Figure 1. The flow diagram of the HS algorithm. Source: Manjarres et al. (2013).
The main advantages of the HS algorithm are its simplicity and versatility (Lee & Geem, 2005). Geem (2008) states that
HS algorithms is a versatile methodology that has been applied for various engineering applications. Comparing to
genetic algorithm memory usage is an advantage of Harmony search algorithm (Lee & Geem, 2005). There various
Improvisation
Yes No Yes
Start
Initialization
HMCR
PAR
Evaluate new Harmony
Add new
Harmony to HM?
Termination
criteria satistied?
StopUpdate the HM
No
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studies that based on comparing meta-heuristic algorithms. Peraza, Valdez & Castillo (2015) compared HS and GA
algorithms on solving benchmark problems and indicated that HS method dominates GA by finding optimal solutions.
Lee & Geem (2005) tested HS on various structural benchmark problems and compared the algorithm with deterministic
mathematical techniques and genetic algorithms, and concluded that HS method shows better results than these two
group of algorithms.
Compared to other meta-heuristics in the literature, the HS algorithm demands less mathematical requirements and
can be easily adapted for solving diverse kinds of engineering optimization problems. (Mahdavi et al., 2007; Orman, &
Mahdavi, 2008). The method is applied to the various problems such as vehicle locomotion, pipeline design; application
of multi-user detection problem, application of access point location problem (Geem et al., 2005; Gil et al., 2009).
A HS meta-heuristic algorithm was conceptualized using the musical process of searching for a perfect state of harmony
(Geem & Kim, 2001). Musical performances search to find agreeable harmony as defined by an aesthetic standard, just
as the optimization process seeks to find a perfect solution as determined by an objective function.
In Figure 2(a), shows the details of the analogy between the method developed for capturing appropriate harmony in
music (music improvisation) and the processes performed to achieve an optimum solution in engineering problems.
Harmony search, a heuristic algorithm produced by musician improvisation, is a musical metaheuristic optimization
method. The method is based on the principle of obtaining the best melody in terms of harmony with notes played by
orchestra musicians. In the method, the orchestra can be obtained by optimizing the result, the objective function, and
the best solution approach, while the most aesthetic melody can be obtained by playing all orchestral elements in
harmony with each other.
Figure 2(a). Analogy between music improvisation and engineering optimization. Source: Lee & Geem (2005).
Figure 2(b). The simulation between music improvement and engineering optimization. Source: Lee & Geem (2005).
As shown in Figure 2(b), the options (do, mi and sol) were selected from the instruments in response to which question,
respectively, which should be subtracted from each of the three available instruments in order to create a proper
harmony. Similarly, the answer to the question of which values of the variables should be chosen to minimize a function
bound to three variables is given as f (100, 300, 500). While the aesthetic qualities of notes and tones played with
different instruments are improved by practicing in music studies, this improvement is realized by successive iterations
in the function solution.
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The HS process consists of five-steps:
Step 1. Defining the problem and solution parameters: The objective function and variables of the function, which will
be used in the solution to the problem, are as defined as follows:
Objective function f(x)
Decision variables, xi ∈ Xi, i = 1,2, … , N
(2)
In this context, f(x) refers to the objective function; xi refers to the variables, Xi refers to the range; and refers to the
number of variables in the function. Parameters such as harmony memory size (HMS) which harmony search method
requires in order to solve an optimization problem, harmony memory considering rate (HMCR), and a maximum number
of the iteration are defined at this stage.
Step 2. Generation of Harmony Memory: Harmony memory is where all solution vectors and the values the objective
function obtains as a result of each iteration are stored. This matrix called harmony memory is full of randomly produced
variable values, then the objective function's values corresponding to these produced values are calculated.
Harmony memory matrix:
[
x1
1
x2
1
… xN−1
1
xN
1
x1
2
x2
2
… xN−1
2
xN
1
⋮ ⋮ ⋱ ⋮ ⋮
x1
HMS−1
x2
HMS−1
… xN−1
HMS−1
xN
HMS−1
x1
HMS
x2
HMS
… xN−1
HMS
xN
HMS
]
⇒
[
f(x1
)
f(x2
)
⋮
f(xHMS−1
)
f(xHMS
) ]
(3)
Step 3. Generation of new harmony: In this step, a new harmony is established through using the values in the harmony
memory. The elements of the new harmony vector are generated according to the possibility of HMCR by either using
the elements of the harmony memory or allocating a random value to X range as applied in the second step. For this
purpose, firstly a random number is selected between 0 and 1 values. If the randomly produced number corresponds
to the HMCR possibility, which has a value between 0 and 1, the new vector element can be picked among the elements
in the harmony memory. If the randomly produced number does not correspond to the HMCR possibility, the new
vector element is randomly chosen among the variables in the range, and not picked from the harmony memory.
xi
′
= {
xi
′
ϵ {xi
1
, xi
2
, xi
3
, … , xi
HMS
}
xi
′
ϵ Xi
HMCR possibility
(1 − HMCR) possibility
} i = 1,2, … , N (4)
Step 4. Update of Harmony Memory: At this stage, primarily the objective function is calculated according to the value
of the newly generated solution vector. Afterward, this value is compared to the objective function value of the solution
vectors in the memory. If the objective function value of the newly generated solution vector is better than the values
of the objective function, the newly established harmony solution vector replaces the harmony vector, which has the
worst objective function value, and the worst solution vector is erased from the memory. In this way, better solution
vectors are stored in the harmony memory.
Step 5. Repetition of the 3rd and fourth steps until termination criterion: At this stage, the termination criterion, which
is defined for the problem, is checked. If this criterion is satisfied, the resolution ends, and the best vector found in the
harmony memory is considered the final solution. If this criterion is not met, the 3rd and fourth steps are repeated.
Methodology
The general parameters used in time-cost trade-off optimization formulations are discussed in this section. In this scope,
it is performed to evaluate the daily outputs for activities in the construction of a building were evaluated according to
Harmony Search Method; and then it is developed to the most convenient solution model over its performance
elements including duration and cost. To this end, the project duration and cost were calculated using Eq. 5; and the
most convenient solutions were attempted to be obtained through the HS model.
Z = ∑ ∑ (Qi ∗ Ci
k
) + C ∗ EFn+1k∈Ki
n
i=1
EFi = ESi + ∑ ti
k
k∈Ki
i=0, ............, n+1 (5)
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ESj = {EFi}i∈pj
max
j=1, ............., n+1
ES0 = 0
Here, Z refers to the total cost of the project; n refers to the number of activity in the project; Qi refers to the amount
of ith
activity; Ci
k
means the direct unit cost of k option of ith
activity; Ki refers to k option set of ith
activity; C means the
indirect cost of the project; EFi refers to the shortest time the activity could be completed; and ESi; refers to the earliest
data the activity could start. ti
k
is the activity duration of k option for i activity and Pj is the activity set right before j th
activity. The steps of the HS model developed for the problem, are demonstrated in the flow chart in Figure 3.
Figure 3. Flow diagram of the proposed solution method. Source: Zalmai (2015).
In multi-objective optimization problems, if a candidate is better than another one, Candidate-1 is absolutely dominant
to Candidate-2 and in terms of both time and cost. Due to two-dominance preferences, the Pareto solution set (the
most convenient solution set) is numbers of 1, 2 and 3 in Figure 4.
Is the new harmony vector better than the
worst harmony vector in the memory? (Is the
new harmony vector a pareto solution?)
Calculate the project duration and cost for the new harmony vector
Step 3. Prepare a new harmony solution vector
(If HMCR criterion is met, the new solution vector is randomly selected among the elements in the harmony memory. If HMCR criterion is not met, it is
randomly created within the range of the activity options.)
Calculate the Project-duration and -cost for solution vector up to HMS
Step 1. Define the problem and solution parameters
The purpose function
The Qi, Ki, ti
k
, Ci
k
, C and Pj
HS parameters
HMS, HMCR, and the maximum iteration number
Step 2. Randomly filling the harmony memory using the values, which may be given to the activity options
Step 4. Update of the harmony
memory (The worst harmony vector is
selected from the harmony memory
and replaced with a newly created and
better harmony vector)
No
Yes
Step 5. Is the termination criterion satisfied?
(max. number of iterations
Write the pareto solution set
No
STOP
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Figure 4. Pareto time-cost solution set. Source: Zalmai (2015).
Implementation of HS on construction project and a case study
The prepared model, the inputs of the model, the results and findings retrieved from the model were evaluated based
on excavation and construction project in Table 2. Firstly, the construction activities of the project were stated; the
relationship among the activities was defined; CPM network of the project was drawn; the amount of the activities to
be conducted was prepared. Afterwards, each activity in the project was investigated in terms of the techniques and
different ways used during the construction. According to this, similar work items in the unit price analysis book of the
Ministry of Environment and Urban Planning were extracted for each activity. The work items, which conducted the
same activity yet displayed differences in terms of the rapidity of completion or unit price, have been detected by using
similar work items. Finally, on the basis of the items related to the activities, it was aimed to obtain the most convenient
time-cost pairs of the project through HS method.
Table 2. The amount and alternative work items of the activities of the project. Source: Zalmai (2015).
ID Activity name
Immediate
predecessor
Approxima
te amount
Alternative work items of activity
according to the unit price analysis book
A Excavation - 4000 m3
(15.010/3B),(15.010/4B)
B Filling with Sealant A 180 m3 (14.1714/1), (14.1717)
(15.140/İB-1)
C Laying lean concrete B 60 m3
(16.001)
D Main Water Insulation C 600 m2
(18.465/2), (18.467/2), (18.468/3)
E
Laying Insulation Screed
(3.5 cm)
D 600 m2
(19.101/MK)
F
Building Foundation
Formwork
E 60 m2
(21.001/02), (21.016), (21.0172)
G
Preparing and Placing
Foundation
Reinforcement
E 20 ton (23.015)
H
Pouring Foundation
Concrete
F, G 360 m3
(16.059/1)
Figure 5. CPM node diagram for the construction project. Source: Stevens (1990).
Co
st
Time
Start
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In the examined construction project, the number of teams is considered one at a minimum rate, and three at a
maximum rate for each activity. The number of teams will be randomly selected for each work item between 1 and 3
range. The daily indirect cost of the construction area is determined as USD 22.5. The data related to selected work
items are given in Table 3.
Table 3. The activities of the construction project. Source: Zalmai (2015).
Activity
Option
no
Work item
no Unit
Unit cost
(USD)
Average production
amount of the
team (unit/day)
Excavation 1 15.010/3B m3
3.31 316.80
2 15.010/4B m3
2.34 256.32
Filling with sealant 1 14.1714/1 m3
1.46 24.00
2 14.1717 m3
4.18 27.84
3 15.140/İB-1 m3
2.10 16.08
Lean concrete 1 16.001 m3
25.89 33.36
Water insulation 1 18.465/2 m2
6.29 68.64
2 18.467/2 m2
7.40 79.92
3 18.468/3 m2
5.45 60.00
Laying screed 1 19.101 m2
4.19 30.80
Building formwork 1 21.001/02 m2
6.75 9.76
2 21.016 m2
13.40 5.36
3 21.017/2 m2
7.50 4.00
Iron making 1 23.015 ton 512.36 0.69
Pouring concrete 1 16.059/1 m3
24.38 79,92
Results and discussion
In construction projects, the shortening of the project duration is taken into consideration due to the positive effect on
costs. In contrast, accelerating the plant causes additional costs and can only reduce the total cost to a certain level. The
analysis of the trade-off between time and cost in construction management is called time-cost trade-off optimization.
However, existing commercial software and methods proposed can provide extremely limited solutions for solving the
problem of time-cost cut-off. From this point, a man-hour account was made for each activity according to the
performance of the workers based on the unit price analysis of the Ministry of Environment and Urbanization. In the
man-hours calculation of an activity, firstly the team speeds of the corresponding work item were found, after which
the average daily production amount of a team was calculated according to the team speeds of the work items. The
calculated man-hours account and unit cost data of the project activities are entered as a program input, and the Pareto
time-cost solution curves are obtained according to the analysis tables of the relevant exposures of the project activities.
Time-cost pairs are shown for the first and one-hundredth iteration in Figure 6. In the first iteration, the Pareto front
includes only one-time-cost pair, shown in red. In the results of the one-hundredth iteration, Pareto front includes three
time-cost pairs. As the number of iterations increases, better results are achieved, after 1000th
iteration the results are
converged. Therefore, the number of iterations of the implementation project was chosen to be 1000.
Figure 6. Analysis results of Pareto time-cost pairs (a) The first iteration, (b) One-hundred iterations.
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Figure 7 shows four different Pareto solutions shown in red for the application project, which is the essential
construction work. For larger projects with a larger number of activities, the number of Pareto solutions is higher. Only
four different optimum solutions could be obtained depending on the number of activities in the project and the number
of alternative work items in the project and the small amount of activity.
Figure 7. Analysis results of Pareto time-cost pairs obtained through 1000 iterations (HMS=50, HMCR=0.9).
Table 4 displays the most convenient time-cost pairs to complete of the project according to different project duration
or project cost restrictions. It is selected any solution based on time or cost restriction of the project. If time restriction
is more important; and if the project has to be completed in 119 days, the most convenient solution is 119 days, USD
40.035,00. All time-cost pairs before this solution point in the Table can be selected and are convenient solutions.
However, the solutions coming after 119 days, USD 39.500,00 are not convenient solutions even though their cost may
be less. This is because the duration of the project is more than 119 days.
Table 4. Pareto result of eight-activities for laying the groundwork through Harmony Analysis with 1000 iterations.
The activities
Excavation Sealant
Lean
concrete Insulation Screed Formwork Iron Concrete
Project
duration
(days)
Project
cost
(USD) A*
B**
A B A B A B A B A B A B A B
117 44.210 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3
118 40.712 2 3 1 3 1 3 2 3 1 3 1 3 1 3 1 3
119 40.035 2 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3
120 39.500 2 3 1 3 1 3 3 3 1 3 1 3 1 3 1 3
*A: Activity no, ** B: Number of teams.
Conclusions
The most important problems in the construction sector, especially for employers and contractors, are project duration
and cost. In other words, these two parameters change inversely proportional to each other. For this reason, it is aimed
to reduce project cost as well as project duration in a multipurpose optimization environment. One of the most
important factors affecting the project cost is the indirect costs incurred during the project although there is no direct
contribution to the continuation of the project. Since many activities in construction projects are done with overtime or
with different technology, the construction speeds of the activities and therefore the duration of the activities are
changing. Also, the operating costs can also be changed as a result of changing the construction technique. Thus, in total
time and total cost optimization, the combination problem, which is difficult to solve, arises. As a solution to this
situation, the approximate solution can be reached quickly by using the metaheuristic methods.
In the present study, time-cost values that can be updated for each activity were obtained based on unit price analysis
data. Afterward, multi-purpose time-cost optimization was carried out considering the team speeds and costs of
different work items belonging to the activities. The prepared model was applied on a real construction project data
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and the results were obtained. Within the scope of the application project, four different solutions were obtained from
the HS model. The time and the cost difference between these solutions is due to the alternative solutions or options
of the three activities in the project (excavation, insulation and mold works). Among these activities, it was determined
that the activity that affects the project cost the greatest is the excavation activity while the activity which affects the
most during the period is the insulation activity. In order to obtain good results from the model, appropriate values of
the model parameters have been investigated and proposed. The model has the feature that it can be adapted to other
construction projects on the market. The duration of the activities was determined on the basis of the data of
construction unit price analysis. In the study, different solutions are proposed for the implementation project
considering the different construction applications of the activities and the obtained data are presented in a way that
can be compared between the solutions. In the present approach, for each activity, without any comparison, one of the
different application forms is selected, and single project duration and project cost are estimated accordingly.
Therefore, the best solutions are ignored according to the importance of time or cost congestions. In the next research,
it is aimed to develop a multi-purpose optimizing planning software that can be applied to the construction sector by
expanding the content of the project.
Acknowledgments
The study was financially supported by the Istanbul University Scientific Research Projects Unit under project number
50827 (Istanbul, Turkey).
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