Supply Chain Performance Improvement: The Role of IT Presented By: Bibhushan Entry No: 2002RME027 Supervisors: Prof. S. Wadhwa and Prof. Anoop Chawla
Presentation Outline Research Context and Motivation Research Objectives An Overview of the Research Work Significant Contributions of Research Work Publications Response to Examiner’s Comments
Research Context and Motivation Simulation for Supply Chain Modeling and Analysis Used for analysis of complex systems Type of problems modeled range from tactical to strategic Object-Oriented Simulation Modeling Detailed model of a complex system can be made by combining basic building blocks Has advantages of inheritance, encapsulation, modularity, etc. Multiple Entity Flow Perspective Five flows: Material, Information, Money, Resource, Decision Focus on Inventory Management to improve IT facilitated SC performance
Research Objectives Highlight the research motivation to Develop an object-oriented supply chain simulation-modeling environment  Develop demonstrative models to illustrate the efficacy of the approach in SC performance Study the inventory management in supply chains working under stochastic demands
Research Objectives Develop an object-oriented supply chain modeling and simulation environment based on multiple-entity flow perspective which should be capable of: Modeling the flow of multiple entities  Stochastic modeling  Adding user-defined decision rules in addition to major control decision rules  User-friendly and cost effective  Robust modeling by means of effective error handling and fool-proofing in data input  Distributed simulation
Research Objectives Analyze inventory management along multiple criteria (demand variance, inventory, service level etc.) Understand the effect of Expected Service Quality (ESQ) on different inventory policies Determine optimal ESQ for each node  Determine optimal Information sharing level for the ESQ levels found above Understand the effect of ordering and capacity constraints on different inventory policies  Determine Optimal Ordering and Capacity constraints for each node Determine the optimal information sharing level for ordering and capacity constraint levels determined above Determine the effect of change in Coefficient of Variance (COV) on each supply chain node Determine the optimal Information sharing level for different COV levels
Overview of Research Work Organization of Thesis Conceptual Framework Simulation Modeling Environment Performance of Supply Chain under Controlled Variability Optimizing ESQ for Supply Chain Nodes Optimizing Optimal Ordering and Capacity Constraint levels for Each Supply Chain Node Understand the Effect of Changing COV on supply chain
Organization of Thesis
Conceptual Framework A Generic Model of Supply Chain   Object Oriented Modeling Perspective   Modeling of Elementary Supply Chain Constructs   Hierarchy of Object Used in Supply Chain Modeling   Modeling Supply Chain Decisions
Simulation Modeling Environment Modeling the Supply Chain Building Blocks Modeling the manufacturing system Modeling the transports Modeling the Player Role Modeling the Supply Chain Node Modeling the Inter-Node Interactions Defining Inter-Node Relationships Defining Inter-Node Lead Times Defining Inter-Node Speeds Defining Inter-Node Distances Defining Product Demands
Simulation Modeling Environment Modeling Supply Chain Decisions Source Selection Policies Inventory Control Decisions Transportation Decisions Production Planning Decisions Performance Metrics Inventory Related Demand Related Service Related Supply Chain Model for Research Model Verification and Validation
Performance of Supply Chain under Controlled Variability Experimental Setup Demand impulses Simulation parameters Balancing the inventory policies Performance metrics considered Effect of Transformed Relative Impulse Amplitude (TRIA) on the Supply Chain   Effect of TRIA on the Supply Chain using Demand Flow Policy (DFP) Effect of TRIA on the Supply Chain using Order Q Policy (OQP) Effect of TRIA on the Supply Chain using (s, S) Policy (sSP) Effect of TRIA on the Supply Chain using (s, Q) Policy (sQP)
Performance of Supply Chain under Controlled Variability Effect of Balance Gap (BG) on the Supply Chain Effect of BG on the Supply Chain using DFP Effect of Negative Impulse BG (NIBG) Effect of Positive Impulse BG (PIBG) Effect of BG on the Supply Chain using OQP Effect of NIBG Effect of PIBG Effect of BG on the Supply Chain using sSP Effect of NIBG Effect of PIBG Effect of BG on the Supply Chain using sQP Effect of NIBG Effect of PIBG
Performance of Supply Chain under Controlled Variability Effect of Number of Impulses (NI) on the Supply Chain Effect of NI on the Supply Chain using DFP Effect of Number of Negative Impulses (NNI) Effect of Number of Positive Impulses (NPI) Effect of NI on the Supply Chain using DFP Effect of NNI Effect of NPI Effect of NI on the Supply Chain using DFP Effect of NNI Effect of NPI Effect of NI on the Supply Chain using DFP Effect of NNI Effect of NPI
Performance of Supply Chain under Controlled Variability Effect of Impulse Width (IW) on the Supply Chain Effect of IW on the Supply Chain using DFP Effect of Negative Impulse Width (NIW) Effect of Positive Impulse Width (PIW) Effect of IW on the Supply Chain using DFP Effect of NIW Effect of PIW Effect of IW on the Supply Chain using DFP Effect of NIW Effect of PIW Effect of IW on the Supply Chain using DFP Effect of NIW Effect of PIW
 
Supply Chain Processes Plan Balances aggregate demand and supply  Source Procures goods and services to meet planned or actual demand  Make Transforms product to a finished state  Deliver Provides finished goods and services  Return Post-delivery customer support
A Generic Model of Supply Chain
Supply Chain Flows Primary Flows (Between Nodes) Material Flow Information Flow Cash Flow Secondary Flows (Only inside Node) Resource Flow Decision Flow
Object Oriented  Supply Chain Simulation Simulation is a technique where computers imitate the operations of various kinds of real-world facilities or processes  (Law and Kelton 1991)  Discrete-event simulation  Object oriented modelling   OOPs based simulator for modeling flexible supply chains
Need for Object Oriented  Supply Chain Simulation Supply chain flexibility offers many challenges and opportunities It offers decision choices as the system evolves which is dynamic in nature There is a need for developing a modeling environment to deal with flexibility and dynamic decision making A OOPs based simulation system is developed and explored for its efficacy in this research
Advantages of  Object Oriented Modeling Inheritance A class of objects can itself be linked to one or several super-classes from which it acquires characteristics and behavior  Encapsulation  Describes its characteristics along with its relationships to other components and the functionality of the object  Allows structured development of the model  Hides unimportant details  Modularity   Provides a very high degree of code reusability
Advantages of  Object Oriented Modeling Allows the model builder to develop the models with much less effort   Suitable for  modeling  distributed systems having client-server architecture   Plug-and-play software capability Interoperability across the network Platform independence Allows complex systems to be constructed with minimum of redundant work
Advantages of  Object Oriented Modeling A logical choice for developing custom or dedicated simulation models  Sub-components may be prefabricated by some expert group for a specific need or application  Productivity of software development improves if code is reused, since the specific modules are already extensively tested by their developers
Advantages of  Object Oriented Modeling Provides a natural mapping paradigm which allows one-to-one mapping between objects in the system being modeled and their abstractions in the object model  Allows the developer to achieve a faster transition of the conceptual model into the software implementation  Object-oriented models generally have a cleaner structure than the event oriented ones
Overall Architecture Basic building blocks are used to create some lower level complex objects   Lower level objects are then used to define the higher level objects   Level 1  objects are made up of basic building blocks   Basic building blocks are combined with the object(s) of  level 1  to form  level 2  objects
Object Oriented Modeling of  Supply Chains Supply chain decision making requires rapid and flexible modeling approach at various levels of detail  Object oriented modeling can be used for  Designing and implementing reusable classes for building models of supply chains Creating a supply chain object library  Facilitates rapid model development  Aid in application of the modeling architecture to specific scenarios at various levels of abstraction
Object Oriented Features in Arena Simulation Environment Offers model development in object oriented manner by means of objects called “modules”  Modules are essentially composed of other basic level modules  Once properly developed, these modules can be reused in other simulation models  However…
Limitations of Object Oriented Features in Arena Modules can be run only on systems having ARENA  Version Conflicts Not suitable for distributed computing  Cost of buying this simulation package  Additional cost of buying the customized module libraries  What is the solution then?
Generic Programming Languages Not as easy as developing models using simulation packages  However,  It is more general and the SC flexibility related issues can be modeled in detail. Availability of customized object libraries for a variety of applications can significantly reduce the time and effort involved in model building process  It offers platform independence to a large extent
IT tool used: VB.Net Ease of designing the user interface Now fully object-oriented Provides a very high degree of platform independence   only for Windows based platforms however Supply chain flexibility and dynamic decision making can be developed as a customized option.
Research Gaps Need to develop simulation tools ideally suited for flexible supply chain simulation  Effective modeling of Supply Chain Flexibility Web-based simulation environment  Demonstrate benefits of collaborative decision making Non-deterministic and dynamic modeling Analyzing the impact of different control decisions in an integrated manner  Distributed computing needs to be explored
Research Gaps Need to study the impact of information sharing under different IT options Supply Chain performance under different levels of Demand History, Service Level, Demand Variance needs to be studied There is need for demonstrative models to illustrate the benefits of IT tools focused on modeling of the flexible supply chains.
Overview of the Research Work Development of the IT tools for modeling Flexibility and Dynamic decision making Manufacturing systems and supply chains were modelled in terms of five types of flows:  information  flow,  decision  flow,  material  flow,  resource  flow and  money  flow   Extended the Multiple Entity flow perspective proposed by Wadhwa & Rao (2003) Development of demonstrative simulation models for illustrating supply chain performance improvement by the use of IT
Overview of the Research Work Supply Chain performance improvement under flexibility and dynamic decision making. Focus on inventory management. Comparison of Inventory Control Policies under Deterministic Variability Effect of Demand History on Supply Chain Performance  Effect of Service Level on Supply Chain Performance  Effect of Demand Variance on Supply Chain Performance
Supply Chain Management Defined SCM is “the integration of business processes from end-user through original suppliers that provides products, services, and information that add value for customers”  (Lambert et. al. (1998)
Modeling Elementary Supply Chain Constructs Classification of Objects Multiple Entity Flow Perspective   Action Points as Processes in the System
Classification of Objects
Multiple Entity Flow Perspective
Action Points as  Processes in the System
Hierarchy of Object Used in Supply Chain Modeling   Modeling of a Supply Chain Network   Modeling of Supply Chain Nodes   Modeling of Supply Chain Operations   Modeling the Manufacturing System
Levels of Abstraction for Supply Chain Modeling
Modeling of a Supply Chain Network   As a collection of supply chain nodes   Each node is a fully autonomous unit   Define relationships between each pair of nodes   Two types of relationships   Buyers (can select Sellers) Sellers (can only be selected) Constrained relationships  By the level of respective nodes
Integration of Supply Chain Nodes
Multiple Supply Chains in a Collection of Supply Chain Nodes
Modeling of Supply Chain Nodes Two kinds of Nodes: Manufacturing (Value-adding) Non-Manufacturing ( store the material and supply it to other nodes ) Flows through each node: Material flow Information flow Money flow   Flows Inside node Resource Flow Decision Flow
Modeling of Supply Chain Nodes Five Processes Plan, Source, Make, Deliver and Return   Return Out of scope of this work Store Additional Process
A Manufacturing Node
A Non-manufacturing Node
Integration of Major Supply Chain Operations
Make Manufacturing operations   Product quantity is decided by  planning   Produces the goods according to the control policies   determined by  production planning   Routing Scheduling
Source Decides the sellers from whom to procure  necessary goods A sourcing policy is a decision rule that determines the best seller(s) out of a number of available sellers in accordance with some predefined criterion e.g. Maximum Inventory, Minimum Lead Time etc.
Deliver (Transportation) Out of a number of transports one or more transports are selected based on some pre-defined transportation policy  like Maximum Speed Minimum Cost Maximum Capacity
Inventory Management Concerned with maintenance of sufficient amount of inventory to fulfil demands   Whenever the inventory of any item falls below the critical levels, the inventory management sends the order(s) to procure the required material or product to planning operation   Planning subsequently decides either to make  or buy the required product
Modeling the  Manufacturing System   Can be modeled by combining two basic building blocks Materials (Transformed or Consumed) Resources (Negligible Transformation/Consumption) One or more resource is used to perform some operation on the material (called  process )   Each product requires some processes to be performed in a specific sequence   Two decisions are taken before each process Resource selection Material selection
Typical Material Processing in a Manufacturing System
Modeling Supply Chain Decisions   Source Selection Policies   Inventory Control Decisions   Transportation Decisions   Production Planning Decisions
Source Selection Policies Classification (based on no. of sources) Single Source Multiple Source Transport Based.   Source Selection Rules Shortest distance Minimum cost Maximum inventory Preference selection Probability based selection (only for multiple source policies) User defined selection (only for single source policies)
Source Selection Policies
Probability Based Source Selection
Multiple Source Selection
Inventory Control Decisions   Demand Flow  Order Q  Order Upto  (s, Q) Policy  (s, S) Policy  Updated (s, S) Policy Days of Supply, Demand Based (DOS Demand)   Days of Supply, Forecast Based ( DOS Forecast)
Inventory Control Decisions
Updated (s, S) Policy
Updated (s, S) Policy Reorder Level ( s ) is calculated as Where LT  is the lead time of the selected source  σ  is the estimate of standard deviation of the demand in previous  n  periods  Z  is the standard normal variate corresponding to the desired service level  Special Cases n -period moving average ( Z   =   0 ) Demand Flow  ( n =  1,  Z =   0 )
DOS Demand
DOS Forecast
Transportation Decisions   Each transport uses some transportation mode e.g.  rail ,  road ,  air , or  water Depending on the location, not all transports may be possible for a node pair  Alternative transports are selected based on which transport modes are available between a node pair
Transportation Decisions   Alternative transports differ according to their specific characteristics  Each transport has some properties like capacity speed, cost, etc  Transport selection rules Maximum speed Maximum volume capacity Maximum weight capacity Minimum cost User defined transport selection
Transportation  Selection Policies
More Classifications in Transports The loading in the selected transport may again be of two types Pooled (all the products shipped between a node-pair are sent through the same transport) Non-pooled (different products are shipped through different transports) Based on capacity utilization of transport FTL (Full Truck Load) LTL (Less than Truck Load)
Transport selection with pooled transports
Transport selection with non pooled transports
Production Planning Decisions   Routing Concerned with selection of best possible resources out of a number of available resources   Scheduling Decides the timing of each process or each job in the manufacturing system   Quantity to be produced is determined by the inventory policy
Production Planning Decisions   Options Available  Produce as directed by inventory policy Produce short batches Once the product is routed to a resource, it is added to the queue of the corresponding resource   Routing policy is used to select the next resource  for the next process when current processing is over Sequence of resource selection and allocation continues until all the processes on the job are completed
Production Planning Operation
Determining the Make Quantity
Resource Selection Policies
Modeling the  Supply Chain Building Blocks   Consists of  Modeling the Manufacturing System Modeling the Transports   Modeling the Player Role   Modeling the Supply Chain Node   Modeling Node Interactions   Different objects in the SC Network are linked with each other, they can be represented using the concepts of Relational Database Management System (RDBMS)
Modeling the  Manufacturing System
Modeling the Transports
Modeling the Player Role
Modeling the Supply Chain Node
Performance Metrics Inventory related Minimum Inventory Maximum Inventory Total Inventory Average Inventory Standard Deviation of Inventory
Performance Metrics Used Service related Backorders Stockouts Fill Rate Service Level Demand related Minimum Demand Maximum Demand Total Demand Average Demand Standard Deviation of Demand
Supply Chain Performance Under Deterministic Variability Experimental Setup Demand Impulses Simulation Parameters Balancing the Inventory Policies Effect of Impulse Amplitude Effect of Impulse Width Effect of Step Width Effect of Number of Impulses
Demand Impulses
Simulation Parameters Variable 1 1 1 Impulse Width 1 Variable 1 1 Number of Impulses 0 0 Variable 0 Balance Gap 0.9 and 1.9 0.9 and 1.9 0.9 and 1.9 Variable Impulse Amplitude 100 100 100 100 Mean Demand 2 2 2 2 Transportation Lead Time (Days) 2 2 2 2 Information Lead Time (Days) 90 90 90 90 Observation Period (Days) 20 20 20 20 Warmup Period (Days) 110 110 110 110 Run Length (Days) Step Width Number of Impulses Balance Gap Demand Amplitude Parameter
Balancing the Policies Each policy was balanced so that all of them gave same results for the test demand under steady state condition Demand Flow:  The test demand was a constant demand of 100 units per week. To fulfill the current obligations, each node has to keep a minimum of 100 units. Each node has to keep an initial inventory equal to four weeks of demand. As a result, an initial inventory of 400 units was allocated to each node. Order Q:  In this policy, orders are placed even when no there is no demand. Therefore, inventory builds up for each node, until the actual demand is received. As a result, all nodes only need to keep an inventory equal to the value of demand per week (100 units).
Balancing the Policies (s, Q) Policy:  The initial inventories for each node were same as those for demand flow policy. A reorder point ( s ) of 400 and order quantity ( Q ) of 100 was set for this policy. (s, S) Policy:  Initial inventories were kept same as the demand flow policy. Both reorder point ( s ) and reorder level ( S ) were set to be 100 units.
Effect of Impulse Amplitude Effect on Individual Supply Chain Nodes Effect on Retailer Effect on Wholesaler Effect on Distributor Effect on Manufacturer Effect of each policy on the Supply Chain Effect along the Supply Chain
Effect of Amplitude on  Individual Supply Chain Nodes Performance Metrics Used Total Inventory Std. Dev. of Inventory Backorders Stockouts Std. Dev. of Demands
Retailer’s Total Inventory
Retailer’s Std. Dev. of Inventory
Retailer’s Backorders
Retailer’s Stockouts
Wholesaler’s Total Inventory
Wholesaler’s Std. Dev. of Inventory
Wholesaler’s Backorders
Wholesaler’s Stockouts
Wholesaler’s Std. Dev. of Demand
Distributor’s Total Inventory
Distributor’s Std. Dev. of Inventory
Distributor’s Backorders
Distributor’s Stockouts
Distributor’s Std. Dev. of Demand
Manufacturer’s Total Inventory
Manufacturer’s  Std. Dev. of Inventory
Manufacturer’s Backorders
Manufacturer’s Stockouts
Manufacturer’s  Std. Dev. of Demand
Effect of Amplitude on  Supply Chain as a Whole Demand Flow Policy Order Q Policy (s, S) Policy (s, Q) Policy
Demand Flow Policy
Total Inventory
Std. Dev. of Inventory
Backorders
Stockouts
Std. Dev. of Demand
Total Inventory
Std. Dev. of Inventory
Backorders
Stockouts
Std. Dev. of Demand
Order Q Policy
Total Inventory
Std. Dev. of Inventory
Backorders
Stockouts
Std. Dev. of Demand
(s, S) Policy
Total Inventory
Std. Dev. of Inventory
Backorders
Stockouts
Std. Dev. of Demand
(s, Q) Policy
Total Inventory
Std. Dev. of Inventory
Backorders
Stockouts
Std. Dev. of Demand
Effect of Amplitude on the  Supply Chain as a Whole Type of Impulse Positive Impulse (0.9) Negative Impulse (-0.9) Performance Metrics Used Total Inventory Std. Dev. of Inventory Backorders Stockouts Std. Dev. of Demands
Negative Impulse Total Inventory
Std. Dev. of Inventory
Backorders
Stockouts
Std. Dev. of Demand
Positive Impulse Total Inventory
Std. Dev. of Inventory
Backorders
Stockouts
Std. Dev. of Demand
Effect of Demand History on  Supply Chain Performance Experimental Setup No Information Sharing Effect on Individual Nodes Effect on Whole Supply Chain and Effect along the Supply Chain Partial Information Sharing Full Information Sharing Comparison of Information Sharing Levels
No Information Sharing
Effect on Individual  Supply Chain Nodes Retailer Wholesaler Distributor Manufacturer
Retailer’s Total Inventory
Retailer’s Maximum Inventory
Retailer’s Std. Dev. of Inventory
Retailer’s Backorders
Retailer’s Stockouts
Wholesaler’s Total Inventory
Wholesaler’s Std. Dev. of Inventory
Wholesaler’s Backorders
Wholesaler’s Stockouts
Wholesaler’s Std. Dev. of Demand
Distributor’s Total Inventory
Distributor’s Std. Dev. of Inventory
Distributor’s Backorders
Distributor’s Stockouts
Distributor’s Std. Dev. of Demand
Manufacturer’s Total Inventory
Manufacturer’s  Std. Dev. of Inventory
Manufacturer’s Backorders
Manufacturer’s Stockouts
Manufacturer’s  Std. Dev. of Demand
Effect on Supply Chain and Effect Along the Supply Chain
Total Inventory
Std. Dev. of Inventory
Backorders
Stockouts
Std. Dev. of Demand
Organization of Thesis
Organization of Thesis
Organization of Thesis
Organization of Thesis
Organization of Thesis
Significant Contributions of the Research Work  Development of an object-oriented supply chain simulation environment  Role of IT based tools are developed and used to study IT facilitated information and decision flows in flexible supply chains is studied Development of a framework that incorporates different IT facilitated control policies in SCs  Comparison for inventory policies under deterministic variability and information sharing Analysis of Supply chain performance under different levels of demand information (IT focus)
Significant Contributions of the Research Work  Analysis of Supply chain performance under different of Service levels Analysis of Supply chain performance under different levels of demand variance Analysis of supply chain performance under different level of information sharing with Different levels of demand history Different service levels Different demand variances
Limitations and  Scope for Future Research The modeling environment can be extended in more directions like Closed loop supply chains by adding return process Manufacturing operations can be extended to include different kinds of production facilities ….  Focus on Inventory management only…
List of Publications Published/Accepted for Publication Postponement strategies for re-engineering of automotive manufacturing: knowledge-management implications , International Journal of Advanced Manufacturing Technology, Article in Press, doi 10.1007/s00170-006-0679-z. Hybrid Tabu-Sample Sort Simulated Annealing (SSA) with Fuzzy Logic Controller: CIM System Context , Studies in Informatics and Control, June 2006, Volume 15, Number 2. Flexible Supply Chains: A Context for Decision Knowledge Sharing and Decision Delays , Global Journal of Flexible Systems Management, Volume 7 Numbers 3 & 4, July -Dec 2006 (Accepted for Publication). Impact of Supply Chain Collaboration on Customer Service Level and Working Capital , Global Journal of Flexible Systems Management (Accepted for Publication).
List of Publications Under Review A multi-criteria customer allocation problem in supply chain environment: an artificial immune system with fuzzy logic controller based approach , International Journal of Computers Communication and Control. Inventory performance of some supply chain inventory policies under impulse demands , International Journal of Production Research, Manuscript ID: TPRS-2007-IJPR-0111. Communicated An Object Oriented Framework for Modeling Control Policies in a Supply Chain , International Journal of Value Chain Management
List of Publications National / International Conferences Web Based Virtual Supply Chain Modeling to Enhance Learning ,  The International Conference on e-Learning (ICEL 2006), University of Quebec in Montreal, Canada, June 22-23. Supply Chain Modeling: The agent based Approach , 12th IFAC Symposium on Information Control Problems in Manufacturing (INCOM-2006), Saint-Etienne, France, May 17-19. Object-Oriented Approach for Simulation of Supply Chain , International Congress on Logistics and SCM Systems (ICLS-2006), Kaohsiung, Taiwan, May 1-2. Comparison of some Supply Chain Management Software Applications ,  National Conference on Advances in Mechanical Engineering (AIME-2006), January 20-21.
Response to  Examiner’s Comments
Comments of Examiner 1 No Information Sharing: Is it best for individual wholesalers and retailers?  As we move higher in the supply chain, the demand variability increases because of the inventory policy used  It is not that no information sharing is good for individual wholesalers and retailers, information sharing is just less important for them. Full Information Sharing: Is it best for the overall system? Whether full information sharing is best for the system or not is dependent on the inventory policy used  The thesis aims to demonstrate that after some particular level of information sharing, the investment in IT may not be economically justified
Comments of Examiner 1 If answers to (1) and (2) above is yes, then explain why optimization on IS level (information sharing) is necessary? Why would an intermediate value (of IS) would be optimal? Whose objective have you considered? Individual wholesalers/retailers or the whole system? Or a combination of the two? It is important to find the level and type of information sharing  On page xxvii: IT should be information technology The required change has been made. Uncertainty in supply chain is demand side and the lead time size. When you consider disturbances: you could have considered lead time disturbances. We consider this as a future area of research
Comments of Examiner 1 Advanced IT means: continuous review policies (for inventory). What implications does it have for your thesis? In a continuous review policy, the inventory position is continuously monitored  Review period is one day; all the policies in our research are the continuous review policies  For single node (such as wholesaler or retailer): given demand and lead time uncertainty: optimal policy for lot sizing can be devised. Then it could be used in your simulation. Decentralized decision making is found to deteriorate the supply chain performance  The decisions of one node may indirectly affect the performance of other (interaction effects)
Comments of Examiner 1 A schematic diagram of supply chain (number of plants), distributor (numbers) and the wholesaler/retailers (numbers) considered in the thesis can be given. A schematic diagram of the supply chain considered in this thesis is given on page 136. Description of the same is given in section 4.5  Main focus of thesis is determination of optimal levels of controllable factors such as … modifying the thesis title. Motivation of this research is to bring the information technology (IT) as a performance improvement solution in the supply chain  Information  sharing and IT are mutually complimentary  The research highlights where and how much information needs to be shared for the optimal performance  Factors beyond the control of decision makers (uncertainty) and factors under decision-makers’ control … readability of the thesis. The required tables have been added in the Appendix A
Comments of Examiner 2 The current developed framework is limited to only two players, i.e. manufacturing and inventory … more than three players? There are four players in the supply chain considered in this research:  Retailer ,  Wholesaler ,  Distributor  and  Manufacturer   In addition to the inbuilt player roles like supplier, manufacturer, distributor, wholesaler and retailer, users can also define their own  Player Roles .  Network manufacturing is a new arena for modern manufacturing environment. How could … contribution in this field? For network manufacturing also, this framework can still handle the execution side  In network manufacturing, the manufacturing of the finished product takes place through a coordination of multiple autonomous players. Such a network will have most of the players as manufacturing type players.  This framework can be used where higher level modeling of the manufacturing system is sufficient
Comments of Examiner 2 In this research, “overall supply chain cost” has been used as the major criterion for the supply chain performance. In fact, there are many Key Performance Indicators (KPI) reported in the supply chain management research work, such as agilability, lead time, flexibility, expandability, trust, etc. How could you consider these issues into your research framework? The research framework, in its present form, has only the KPIs which were required for this research work, i.e. those related to inventory management  Since the framework is based on object oriented methodology, multiple KPI libraries can be added to it as and when need arises  What are the major bottlenecks in the implementation of the developed framework in real-life industrial case? The framework has been developed considering a very generic nature of the supply chain
Comments of Examiner 2 What are the major limitations of the developed framework in this thesis? The return operation of a supply chain is not available in the framework.  In the future, some other major supply chain operations may be added in the framework. The effectiveness of the simulation environment can be immensely improved by incorporating some optimization algorithms for simpler supply chain decisions and some meta-heuristics for complex problems.  Another important direction for future work is to provide animated simulation similar to that available in other simulation languages.
Thank You
Questions

Phd Defence 25 Jan09

  • 1.
    Supply Chain PerformanceImprovement: The Role of IT Presented By: Bibhushan Entry No: 2002RME027 Supervisors: Prof. S. Wadhwa and Prof. Anoop Chawla
  • 2.
    Presentation Outline ResearchContext and Motivation Research Objectives An Overview of the Research Work Significant Contributions of Research Work Publications Response to Examiner’s Comments
  • 3.
    Research Context andMotivation Simulation for Supply Chain Modeling and Analysis Used for analysis of complex systems Type of problems modeled range from tactical to strategic Object-Oriented Simulation Modeling Detailed model of a complex system can be made by combining basic building blocks Has advantages of inheritance, encapsulation, modularity, etc. Multiple Entity Flow Perspective Five flows: Material, Information, Money, Resource, Decision Focus on Inventory Management to improve IT facilitated SC performance
  • 4.
    Research Objectives Highlightthe research motivation to Develop an object-oriented supply chain simulation-modeling environment Develop demonstrative models to illustrate the efficacy of the approach in SC performance Study the inventory management in supply chains working under stochastic demands
  • 5.
    Research Objectives Developan object-oriented supply chain modeling and simulation environment based on multiple-entity flow perspective which should be capable of: Modeling the flow of multiple entities Stochastic modeling Adding user-defined decision rules in addition to major control decision rules User-friendly and cost effective Robust modeling by means of effective error handling and fool-proofing in data input Distributed simulation
  • 6.
    Research Objectives Analyzeinventory management along multiple criteria (demand variance, inventory, service level etc.) Understand the effect of Expected Service Quality (ESQ) on different inventory policies Determine optimal ESQ for each node Determine optimal Information sharing level for the ESQ levels found above Understand the effect of ordering and capacity constraints on different inventory policies Determine Optimal Ordering and Capacity constraints for each node Determine the optimal information sharing level for ordering and capacity constraint levels determined above Determine the effect of change in Coefficient of Variance (COV) on each supply chain node Determine the optimal Information sharing level for different COV levels
  • 7.
    Overview of ResearchWork Organization of Thesis Conceptual Framework Simulation Modeling Environment Performance of Supply Chain under Controlled Variability Optimizing ESQ for Supply Chain Nodes Optimizing Optimal Ordering and Capacity Constraint levels for Each Supply Chain Node Understand the Effect of Changing COV on supply chain
  • 8.
  • 9.
    Conceptual Framework AGeneric Model of Supply Chain Object Oriented Modeling Perspective Modeling of Elementary Supply Chain Constructs Hierarchy of Object Used in Supply Chain Modeling Modeling Supply Chain Decisions
  • 10.
    Simulation Modeling EnvironmentModeling the Supply Chain Building Blocks Modeling the manufacturing system Modeling the transports Modeling the Player Role Modeling the Supply Chain Node Modeling the Inter-Node Interactions Defining Inter-Node Relationships Defining Inter-Node Lead Times Defining Inter-Node Speeds Defining Inter-Node Distances Defining Product Demands
  • 11.
    Simulation Modeling EnvironmentModeling Supply Chain Decisions Source Selection Policies Inventory Control Decisions Transportation Decisions Production Planning Decisions Performance Metrics Inventory Related Demand Related Service Related Supply Chain Model for Research Model Verification and Validation
  • 12.
    Performance of SupplyChain under Controlled Variability Experimental Setup Demand impulses Simulation parameters Balancing the inventory policies Performance metrics considered Effect of Transformed Relative Impulse Amplitude (TRIA) on the Supply Chain Effect of TRIA on the Supply Chain using Demand Flow Policy (DFP) Effect of TRIA on the Supply Chain using Order Q Policy (OQP) Effect of TRIA on the Supply Chain using (s, S) Policy (sSP) Effect of TRIA on the Supply Chain using (s, Q) Policy (sQP)
  • 13.
    Performance of SupplyChain under Controlled Variability Effect of Balance Gap (BG) on the Supply Chain Effect of BG on the Supply Chain using DFP Effect of Negative Impulse BG (NIBG) Effect of Positive Impulse BG (PIBG) Effect of BG on the Supply Chain using OQP Effect of NIBG Effect of PIBG Effect of BG on the Supply Chain using sSP Effect of NIBG Effect of PIBG Effect of BG on the Supply Chain using sQP Effect of NIBG Effect of PIBG
  • 14.
    Performance of SupplyChain under Controlled Variability Effect of Number of Impulses (NI) on the Supply Chain Effect of NI on the Supply Chain using DFP Effect of Number of Negative Impulses (NNI) Effect of Number of Positive Impulses (NPI) Effect of NI on the Supply Chain using DFP Effect of NNI Effect of NPI Effect of NI on the Supply Chain using DFP Effect of NNI Effect of NPI Effect of NI on the Supply Chain using DFP Effect of NNI Effect of NPI
  • 15.
    Performance of SupplyChain under Controlled Variability Effect of Impulse Width (IW) on the Supply Chain Effect of IW on the Supply Chain using DFP Effect of Negative Impulse Width (NIW) Effect of Positive Impulse Width (PIW) Effect of IW on the Supply Chain using DFP Effect of NIW Effect of PIW Effect of IW on the Supply Chain using DFP Effect of NIW Effect of PIW Effect of IW on the Supply Chain using DFP Effect of NIW Effect of PIW
  • 16.
  • 17.
    Supply Chain ProcessesPlan Balances aggregate demand and supply Source Procures goods and services to meet planned or actual demand Make Transforms product to a finished state Deliver Provides finished goods and services Return Post-delivery customer support
  • 18.
    A Generic Modelof Supply Chain
  • 19.
    Supply Chain FlowsPrimary Flows (Between Nodes) Material Flow Information Flow Cash Flow Secondary Flows (Only inside Node) Resource Flow Decision Flow
  • 20.
    Object Oriented Supply Chain Simulation Simulation is a technique where computers imitate the operations of various kinds of real-world facilities or processes (Law and Kelton 1991) Discrete-event simulation Object oriented modelling OOPs based simulator for modeling flexible supply chains
  • 21.
    Need for ObjectOriented Supply Chain Simulation Supply chain flexibility offers many challenges and opportunities It offers decision choices as the system evolves which is dynamic in nature There is a need for developing a modeling environment to deal with flexibility and dynamic decision making A OOPs based simulation system is developed and explored for its efficacy in this research
  • 22.
    Advantages of Object Oriented Modeling Inheritance A class of objects can itself be linked to one or several super-classes from which it acquires characteristics and behavior Encapsulation Describes its characteristics along with its relationships to other components and the functionality of the object Allows structured development of the model Hides unimportant details Modularity Provides a very high degree of code reusability
  • 23.
    Advantages of Object Oriented Modeling Allows the model builder to develop the models with much less effort Suitable for modeling distributed systems having client-server architecture Plug-and-play software capability Interoperability across the network Platform independence Allows complex systems to be constructed with minimum of redundant work
  • 24.
    Advantages of Object Oriented Modeling A logical choice for developing custom or dedicated simulation models Sub-components may be prefabricated by some expert group for a specific need or application Productivity of software development improves if code is reused, since the specific modules are already extensively tested by their developers
  • 25.
    Advantages of Object Oriented Modeling Provides a natural mapping paradigm which allows one-to-one mapping between objects in the system being modeled and their abstractions in the object model Allows the developer to achieve a faster transition of the conceptual model into the software implementation Object-oriented models generally have a cleaner structure than the event oriented ones
  • 26.
    Overall Architecture Basicbuilding blocks are used to create some lower level complex objects Lower level objects are then used to define the higher level objects Level 1 objects are made up of basic building blocks Basic building blocks are combined with the object(s) of level 1 to form level 2 objects
  • 27.
    Object Oriented Modelingof Supply Chains Supply chain decision making requires rapid and flexible modeling approach at various levels of detail Object oriented modeling can be used for Designing and implementing reusable classes for building models of supply chains Creating a supply chain object library Facilitates rapid model development Aid in application of the modeling architecture to specific scenarios at various levels of abstraction
  • 28.
    Object Oriented Featuresin Arena Simulation Environment Offers model development in object oriented manner by means of objects called “modules” Modules are essentially composed of other basic level modules Once properly developed, these modules can be reused in other simulation models However…
  • 29.
    Limitations of ObjectOriented Features in Arena Modules can be run only on systems having ARENA Version Conflicts Not suitable for distributed computing Cost of buying this simulation package Additional cost of buying the customized module libraries What is the solution then?
  • 30.
    Generic Programming LanguagesNot as easy as developing models using simulation packages However, It is more general and the SC flexibility related issues can be modeled in detail. Availability of customized object libraries for a variety of applications can significantly reduce the time and effort involved in model building process It offers platform independence to a large extent
  • 31.
    IT tool used:VB.Net Ease of designing the user interface Now fully object-oriented Provides a very high degree of platform independence only for Windows based platforms however Supply chain flexibility and dynamic decision making can be developed as a customized option.
  • 32.
    Research Gaps Needto develop simulation tools ideally suited for flexible supply chain simulation Effective modeling of Supply Chain Flexibility Web-based simulation environment Demonstrate benefits of collaborative decision making Non-deterministic and dynamic modeling Analyzing the impact of different control decisions in an integrated manner Distributed computing needs to be explored
  • 33.
    Research Gaps Needto study the impact of information sharing under different IT options Supply Chain performance under different levels of Demand History, Service Level, Demand Variance needs to be studied There is need for demonstrative models to illustrate the benefits of IT tools focused on modeling of the flexible supply chains.
  • 34.
    Overview of theResearch Work Development of the IT tools for modeling Flexibility and Dynamic decision making Manufacturing systems and supply chains were modelled in terms of five types of flows: information flow, decision flow, material flow, resource flow and money flow Extended the Multiple Entity flow perspective proposed by Wadhwa & Rao (2003) Development of demonstrative simulation models for illustrating supply chain performance improvement by the use of IT
  • 35.
    Overview of theResearch Work Supply Chain performance improvement under flexibility and dynamic decision making. Focus on inventory management. Comparison of Inventory Control Policies under Deterministic Variability Effect of Demand History on Supply Chain Performance Effect of Service Level on Supply Chain Performance Effect of Demand Variance on Supply Chain Performance
  • 36.
    Supply Chain ManagementDefined SCM is “the integration of business processes from end-user through original suppliers that provides products, services, and information that add value for customers” (Lambert et. al. (1998)
  • 37.
    Modeling Elementary SupplyChain Constructs Classification of Objects Multiple Entity Flow Perspective Action Points as Processes in the System
  • 38.
  • 39.
  • 40.
    Action Points as Processes in the System
  • 41.
    Hierarchy of ObjectUsed in Supply Chain Modeling Modeling of a Supply Chain Network Modeling of Supply Chain Nodes Modeling of Supply Chain Operations Modeling the Manufacturing System
  • 42.
    Levels of Abstractionfor Supply Chain Modeling
  • 43.
    Modeling of aSupply Chain Network As a collection of supply chain nodes Each node is a fully autonomous unit Define relationships between each pair of nodes Two types of relationships Buyers (can select Sellers) Sellers (can only be selected) Constrained relationships By the level of respective nodes
  • 44.
  • 45.
    Multiple Supply Chainsin a Collection of Supply Chain Nodes
  • 46.
    Modeling of SupplyChain Nodes Two kinds of Nodes: Manufacturing (Value-adding) Non-Manufacturing ( store the material and supply it to other nodes ) Flows through each node: Material flow Information flow Money flow Flows Inside node Resource Flow Decision Flow
  • 47.
    Modeling of SupplyChain Nodes Five Processes Plan, Source, Make, Deliver and Return Return Out of scope of this work Store Additional Process
  • 48.
  • 49.
  • 50.
    Integration of MajorSupply Chain Operations
  • 51.
    Make Manufacturing operations Product quantity is decided by planning Produces the goods according to the control policies determined by production planning Routing Scheduling
  • 52.
    Source Decides thesellers from whom to procure necessary goods A sourcing policy is a decision rule that determines the best seller(s) out of a number of available sellers in accordance with some predefined criterion e.g. Maximum Inventory, Minimum Lead Time etc.
  • 53.
    Deliver (Transportation) Outof a number of transports one or more transports are selected based on some pre-defined transportation policy like Maximum Speed Minimum Cost Maximum Capacity
  • 54.
    Inventory Management Concernedwith maintenance of sufficient amount of inventory to fulfil demands Whenever the inventory of any item falls below the critical levels, the inventory management sends the order(s) to procure the required material or product to planning operation Planning subsequently decides either to make or buy the required product
  • 55.
    Modeling the Manufacturing System Can be modeled by combining two basic building blocks Materials (Transformed or Consumed) Resources (Negligible Transformation/Consumption) One or more resource is used to perform some operation on the material (called process ) Each product requires some processes to be performed in a specific sequence Two decisions are taken before each process Resource selection Material selection
  • 56.
    Typical Material Processingin a Manufacturing System
  • 57.
    Modeling Supply ChainDecisions Source Selection Policies Inventory Control Decisions Transportation Decisions Production Planning Decisions
  • 58.
    Source Selection PoliciesClassification (based on no. of sources) Single Source Multiple Source Transport Based. Source Selection Rules Shortest distance Minimum cost Maximum inventory Preference selection Probability based selection (only for multiple source policies) User defined selection (only for single source policies)
  • 59.
  • 60.
  • 61.
  • 62.
    Inventory Control Decisions Demand Flow Order Q Order Upto (s, Q) Policy (s, S) Policy Updated (s, S) Policy Days of Supply, Demand Based (DOS Demand) Days of Supply, Forecast Based ( DOS Forecast)
  • 63.
  • 64.
  • 65.
    Updated (s, S)Policy Reorder Level ( s ) is calculated as Where LT is the lead time of the selected source σ is the estimate of standard deviation of the demand in previous n periods Z is the standard normal variate corresponding to the desired service level Special Cases n -period moving average ( Z = 0 ) Demand Flow ( n = 1, Z = 0 )
  • 66.
  • 67.
  • 68.
    Transportation Decisions Each transport uses some transportation mode e.g. rail , road , air , or water Depending on the location, not all transports may be possible for a node pair Alternative transports are selected based on which transport modes are available between a node pair
  • 69.
    Transportation Decisions Alternative transports differ according to their specific characteristics Each transport has some properties like capacity speed, cost, etc Transport selection rules Maximum speed Maximum volume capacity Maximum weight capacity Minimum cost User defined transport selection
  • 70.
  • 71.
    More Classifications inTransports The loading in the selected transport may again be of two types Pooled (all the products shipped between a node-pair are sent through the same transport) Non-pooled (different products are shipped through different transports) Based on capacity utilization of transport FTL (Full Truck Load) LTL (Less than Truck Load)
  • 72.
    Transport selection withpooled transports
  • 73.
    Transport selection withnon pooled transports
  • 74.
    Production Planning Decisions Routing Concerned with selection of best possible resources out of a number of available resources Scheduling Decides the timing of each process or each job in the manufacturing system Quantity to be produced is determined by the inventory policy
  • 75.
    Production Planning Decisions Options Available Produce as directed by inventory policy Produce short batches Once the product is routed to a resource, it is added to the queue of the corresponding resource Routing policy is used to select the next resource for the next process when current processing is over Sequence of resource selection and allocation continues until all the processes on the job are completed
  • 76.
  • 77.
  • 78.
  • 79.
    Modeling the Supply Chain Building Blocks Consists of Modeling the Manufacturing System Modeling the Transports Modeling the Player Role Modeling the Supply Chain Node Modeling Node Interactions Different objects in the SC Network are linked with each other, they can be represented using the concepts of Relational Database Management System (RDBMS)
  • 80.
    Modeling the Manufacturing System
  • 81.
  • 82.
  • 83.
  • 84.
    Performance Metrics Inventoryrelated Minimum Inventory Maximum Inventory Total Inventory Average Inventory Standard Deviation of Inventory
  • 85.
    Performance Metrics UsedService related Backorders Stockouts Fill Rate Service Level Demand related Minimum Demand Maximum Demand Total Demand Average Demand Standard Deviation of Demand
  • 86.
    Supply Chain PerformanceUnder Deterministic Variability Experimental Setup Demand Impulses Simulation Parameters Balancing the Inventory Policies Effect of Impulse Amplitude Effect of Impulse Width Effect of Step Width Effect of Number of Impulses
  • 87.
  • 88.
    Simulation Parameters Variable1 1 1 Impulse Width 1 Variable 1 1 Number of Impulses 0 0 Variable 0 Balance Gap 0.9 and 1.9 0.9 and 1.9 0.9 and 1.9 Variable Impulse Amplitude 100 100 100 100 Mean Demand 2 2 2 2 Transportation Lead Time (Days) 2 2 2 2 Information Lead Time (Days) 90 90 90 90 Observation Period (Days) 20 20 20 20 Warmup Period (Days) 110 110 110 110 Run Length (Days) Step Width Number of Impulses Balance Gap Demand Amplitude Parameter
  • 89.
    Balancing the PoliciesEach policy was balanced so that all of them gave same results for the test demand under steady state condition Demand Flow: The test demand was a constant demand of 100 units per week. To fulfill the current obligations, each node has to keep a minimum of 100 units. Each node has to keep an initial inventory equal to four weeks of demand. As a result, an initial inventory of 400 units was allocated to each node. Order Q: In this policy, orders are placed even when no there is no demand. Therefore, inventory builds up for each node, until the actual demand is received. As a result, all nodes only need to keep an inventory equal to the value of demand per week (100 units).
  • 90.
    Balancing the Policies(s, Q) Policy: The initial inventories for each node were same as those for demand flow policy. A reorder point ( s ) of 400 and order quantity ( Q ) of 100 was set for this policy. (s, S) Policy: Initial inventories were kept same as the demand flow policy. Both reorder point ( s ) and reorder level ( S ) were set to be 100 units.
  • 91.
    Effect of ImpulseAmplitude Effect on Individual Supply Chain Nodes Effect on Retailer Effect on Wholesaler Effect on Distributor Effect on Manufacturer Effect of each policy on the Supply Chain Effect along the Supply Chain
  • 92.
    Effect of Amplitudeon Individual Supply Chain Nodes Performance Metrics Used Total Inventory Std. Dev. of Inventory Backorders Stockouts Std. Dev. of Demands
  • 93.
  • 94.
  • 95.
  • 96.
  • 97.
  • 98.
  • 99.
  • 100.
  • 101.
  • 102.
  • 103.
  • 104.
  • 105.
  • 106.
  • 107.
  • 108.
    Manufacturer’s Std.Dev. of Inventory
  • 109.
  • 110.
  • 111.
    Manufacturer’s Std.Dev. of Demand
  • 112.
    Effect of Amplitudeon Supply Chain as a Whole Demand Flow Policy Order Q Policy (s, S) Policy (s, Q) Policy
  • 113.
  • 114.
  • 115.
    Std. Dev. ofInventory
  • 116.
  • 117.
  • 118.
  • 119.
  • 120.
    Std. Dev. ofInventory
  • 121.
  • 122.
  • 123.
  • 124.
  • 125.
  • 126.
    Std. Dev. ofInventory
  • 127.
  • 128.
  • 129.
  • 130.
  • 131.
  • 132.
    Std. Dev. ofInventory
  • 133.
  • 134.
  • 135.
  • 136.
  • 137.
  • 138.
    Std. Dev. ofInventory
  • 139.
  • 140.
  • 141.
  • 142.
    Effect of Amplitudeon the Supply Chain as a Whole Type of Impulse Positive Impulse (0.9) Negative Impulse (-0.9) Performance Metrics Used Total Inventory Std. Dev. of Inventory Backorders Stockouts Std. Dev. of Demands
  • 143.
  • 144.
    Std. Dev. ofInventory
  • 145.
  • 146.
  • 147.
  • 148.
  • 149.
    Std. Dev. ofInventory
  • 150.
  • 151.
  • 152.
  • 153.
    Effect of DemandHistory on Supply Chain Performance Experimental Setup No Information Sharing Effect on Individual Nodes Effect on Whole Supply Chain and Effect along the Supply Chain Partial Information Sharing Full Information Sharing Comparison of Information Sharing Levels
  • 154.
  • 155.
    Effect on Individual Supply Chain Nodes Retailer Wholesaler Distributor Manufacturer
  • 156.
  • 157.
  • 158.
  • 159.
  • 160.
  • 161.
  • 162.
  • 163.
  • 164.
  • 165.
  • 166.
  • 167.
  • 168.
  • 169.
  • 170.
  • 171.
  • 172.
    Manufacturer’s Std.Dev. of Inventory
  • 173.
  • 174.
  • 175.
    Manufacturer’s Std.Dev. of Demand
  • 176.
    Effect on SupplyChain and Effect Along the Supply Chain
  • 177.
  • 178.
    Std. Dev. ofInventory
  • 179.
  • 180.
  • 181.
  • 182.
  • 183.
  • 184.
  • 185.
  • 186.
  • 187.
    Significant Contributions ofthe Research Work Development of an object-oriented supply chain simulation environment Role of IT based tools are developed and used to study IT facilitated information and decision flows in flexible supply chains is studied Development of a framework that incorporates different IT facilitated control policies in SCs Comparison for inventory policies under deterministic variability and information sharing Analysis of Supply chain performance under different levels of demand information (IT focus)
  • 188.
    Significant Contributions ofthe Research Work Analysis of Supply chain performance under different of Service levels Analysis of Supply chain performance under different levels of demand variance Analysis of supply chain performance under different level of information sharing with Different levels of demand history Different service levels Different demand variances
  • 189.
    Limitations and Scope for Future Research The modeling environment can be extended in more directions like Closed loop supply chains by adding return process Manufacturing operations can be extended to include different kinds of production facilities …. Focus on Inventory management only…
  • 190.
    List of PublicationsPublished/Accepted for Publication Postponement strategies for re-engineering of automotive manufacturing: knowledge-management implications , International Journal of Advanced Manufacturing Technology, Article in Press, doi 10.1007/s00170-006-0679-z. Hybrid Tabu-Sample Sort Simulated Annealing (SSA) with Fuzzy Logic Controller: CIM System Context , Studies in Informatics and Control, June 2006, Volume 15, Number 2. Flexible Supply Chains: A Context for Decision Knowledge Sharing and Decision Delays , Global Journal of Flexible Systems Management, Volume 7 Numbers 3 & 4, July -Dec 2006 (Accepted for Publication). Impact of Supply Chain Collaboration on Customer Service Level and Working Capital , Global Journal of Flexible Systems Management (Accepted for Publication).
  • 191.
    List of PublicationsUnder Review A multi-criteria customer allocation problem in supply chain environment: an artificial immune system with fuzzy logic controller based approach , International Journal of Computers Communication and Control. Inventory performance of some supply chain inventory policies under impulse demands , International Journal of Production Research, Manuscript ID: TPRS-2007-IJPR-0111. Communicated An Object Oriented Framework for Modeling Control Policies in a Supply Chain , International Journal of Value Chain Management
  • 192.
    List of PublicationsNational / International Conferences Web Based Virtual Supply Chain Modeling to Enhance Learning , The International Conference on e-Learning (ICEL 2006), University of Quebec in Montreal, Canada, June 22-23. Supply Chain Modeling: The agent based Approach , 12th IFAC Symposium on Information Control Problems in Manufacturing (INCOM-2006), Saint-Etienne, France, May 17-19. Object-Oriented Approach for Simulation of Supply Chain , International Congress on Logistics and SCM Systems (ICLS-2006), Kaohsiung, Taiwan, May 1-2. Comparison of some Supply Chain Management Software Applications , National Conference on Advances in Mechanical Engineering (AIME-2006), January 20-21.
  • 193.
    Response to Examiner’s Comments
  • 194.
    Comments of Examiner1 No Information Sharing: Is it best for individual wholesalers and retailers? As we move higher in the supply chain, the demand variability increases because of the inventory policy used It is not that no information sharing is good for individual wholesalers and retailers, information sharing is just less important for them. Full Information Sharing: Is it best for the overall system? Whether full information sharing is best for the system or not is dependent on the inventory policy used The thesis aims to demonstrate that after some particular level of information sharing, the investment in IT may not be economically justified
  • 195.
    Comments of Examiner1 If answers to (1) and (2) above is yes, then explain why optimization on IS level (information sharing) is necessary? Why would an intermediate value (of IS) would be optimal? Whose objective have you considered? Individual wholesalers/retailers or the whole system? Or a combination of the two? It is important to find the level and type of information sharing On page xxvii: IT should be information technology The required change has been made. Uncertainty in supply chain is demand side and the lead time size. When you consider disturbances: you could have considered lead time disturbances. We consider this as a future area of research
  • 196.
    Comments of Examiner1 Advanced IT means: continuous review policies (for inventory). What implications does it have for your thesis? In a continuous review policy, the inventory position is continuously monitored Review period is one day; all the policies in our research are the continuous review policies For single node (such as wholesaler or retailer): given demand and lead time uncertainty: optimal policy for lot sizing can be devised. Then it could be used in your simulation. Decentralized decision making is found to deteriorate the supply chain performance The decisions of one node may indirectly affect the performance of other (interaction effects)
  • 197.
    Comments of Examiner1 A schematic diagram of supply chain (number of plants), distributor (numbers) and the wholesaler/retailers (numbers) considered in the thesis can be given. A schematic diagram of the supply chain considered in this thesis is given on page 136. Description of the same is given in section 4.5 Main focus of thesis is determination of optimal levels of controllable factors such as … modifying the thesis title. Motivation of this research is to bring the information technology (IT) as a performance improvement solution in the supply chain Information sharing and IT are mutually complimentary The research highlights where and how much information needs to be shared for the optimal performance Factors beyond the control of decision makers (uncertainty) and factors under decision-makers’ control … readability of the thesis. The required tables have been added in the Appendix A
  • 198.
    Comments of Examiner2 The current developed framework is limited to only two players, i.e. manufacturing and inventory … more than three players? There are four players in the supply chain considered in this research: Retailer , Wholesaler , Distributor and Manufacturer In addition to the inbuilt player roles like supplier, manufacturer, distributor, wholesaler and retailer, users can also define their own Player Roles . Network manufacturing is a new arena for modern manufacturing environment. How could … contribution in this field? For network manufacturing also, this framework can still handle the execution side In network manufacturing, the manufacturing of the finished product takes place through a coordination of multiple autonomous players. Such a network will have most of the players as manufacturing type players. This framework can be used where higher level modeling of the manufacturing system is sufficient
  • 199.
    Comments of Examiner2 In this research, “overall supply chain cost” has been used as the major criterion for the supply chain performance. In fact, there are many Key Performance Indicators (KPI) reported in the supply chain management research work, such as agilability, lead time, flexibility, expandability, trust, etc. How could you consider these issues into your research framework? The research framework, in its present form, has only the KPIs which were required for this research work, i.e. those related to inventory management Since the framework is based on object oriented methodology, multiple KPI libraries can be added to it as and when need arises What are the major bottlenecks in the implementation of the developed framework in real-life industrial case? The framework has been developed considering a very generic nature of the supply chain
  • 200.
    Comments of Examiner2 What are the major limitations of the developed framework in this thesis? The return operation of a supply chain is not available in the framework. In the future, some other major supply chain operations may be added in the framework. The effectiveness of the simulation environment can be immensely improved by incorporating some optimization algorithms for simpler supply chain decisions and some meta-heuristics for complex problems. Another important direction for future work is to provide animated simulation similar to that available in other simulation languages.
  • 201.
  • 202.

Editor's Notes

  • #40 A legend may improve the understability of the viewpoint
  • #41 More explanation may be needed
  • #48 Not Necessary
  • #81 Discuss about PK and FK