This document provides an overview of various optimization techniques that have been used for operating multi-reservoir systems, including linear programming, non-linear programming, and dynamic programming. It describes how each technique works and examples of its applications to reservoir systems. Dynamic programming is highlighted as being well-suited for reservoir operations given their multi-stage decision process nature, but it faces computational challenges for problems with more than a few state variables. The document also discusses how combinations of techniques, like linear programming and dynamic programming, have been used to help address some of the limitations.
ASSESSMENT OF LP AND GA AS RESERVOIR SYSTEM ANALYSIS TOOLSIAEME Publication
A reservoir is a huge manmade structure constructed for a number of reasons. It
uses natural water resources and helps in the development of a society. The quantum
of water in a reservoir is a function of the hydrologic characteristics of the region. An
efficient planning and operation of a reservoir is a skill of the water planner. The
works done by researchers in the system analysis of a reservoir are discussed in the
present paper. The most appreciated linear programming (LP) and genetic algorithm
(GA) are studied in the context of system analysis of Urmodi Reservoir in
Maharashtra, India. The objective function is set to minimize the sum of the squared
irrigation demand deficit. Results show that these tools seem to be versatile in nature
and efficiently adopted for reservoir operation purpose.
Application of GIS and MODFLOW to Ground Water Hydrology- A ReviewIJERA Editor
Groundwater is one of the most valuable natural resources, which supports human health, economic
development and ecological diversity. Due to over exploitation, the ground water systems are affected and
require management to maintain the conditions of ground water resources within acceptable limits. With the
development of computers and advances in information technology, efficient techniques for water management
has evolved. The main intent of the paper is to present a comprehensive review on application of GIS
(Geographic Information System) followed by coupling with MODFLOW package for ground water
management and development. Two major areas are discussed stating GIS applications in ground water
hydrology. (i) GIS based subsurface flow and pollution modelling (ii) Selection of artificial recharge sites.
Although the use of these techniques in groundwater studies has rapidly increased since last decade the sucess
rate is very limited. Based on this review , it is concluded that integation of GIS and MODFLOW have great
potential to revolutionize the monitoring and management of vital ground water resources in the future.
ASSESSMENT OF LP AND GA AS RESERVOIR SYSTEM ANALYSIS TOOLSIAEME Publication
A reservoir is a huge manmade structure constructed for a number of reasons. It
uses natural water resources and helps in the development of a society. The quantum
of water in a reservoir is a function of the hydrologic characteristics of the region. An
efficient planning and operation of a reservoir is a skill of the water planner. The
works done by researchers in the system analysis of a reservoir are discussed in the
present paper. The most appreciated linear programming (LP) and genetic algorithm
(GA) are studied in the context of system analysis of Urmodi Reservoir in
Maharashtra, India. The objective function is set to minimize the sum of the squared
irrigation demand deficit. Results show that these tools seem to be versatile in nature
and efficiently adopted for reservoir operation purpose.
Application of GIS and MODFLOW to Ground Water Hydrology- A ReviewIJERA Editor
Groundwater is one of the most valuable natural resources, which supports human health, economic
development and ecological diversity. Due to over exploitation, the ground water systems are affected and
require management to maintain the conditions of ground water resources within acceptable limits. With the
development of computers and advances in information technology, efficient techniques for water management
has evolved. The main intent of the paper is to present a comprehensive review on application of GIS
(Geographic Information System) followed by coupling with MODFLOW package for ground water
management and development. Two major areas are discussed stating GIS applications in ground water
hydrology. (i) GIS based subsurface flow and pollution modelling (ii) Selection of artificial recharge sites.
Although the use of these techniques in groundwater studies has rapidly increased since last decade the sucess
rate is very limited. Based on this review , it is concluded that integation of GIS and MODFLOW have great
potential to revolutionize the monitoring and management of vital ground water resources in the future.
Assessing the ability of SWAT as a water quality model in the Lake Victoria b...Timo Brussée
There is a need for a water quality model for use in the Lake Victoria basin countries in East-Africa. The
region is characterised by data scarcity, a tropical climate and riverine, lacustrine tidal wetlands which form
an important buffer to riverine pollution of the lake. These characteristics of the basin form a challenge for
water quality models. The objective is to state the strengths and weaknesses of a potential water quality
model under these challenging conditions. This objective is executed with the soil water assessment tool
(SWAT) in a catchment of the Lake Victoria Basin as pilot area. The pilot area of the Mara river basin is
hydrologically complex containing tropical and plantation forest, savanna, grasslands, bi-annual agriculture,
shrublands and wetlands. It has varied soil types and bi-annual rain seasons
The study consist of literature research and flow simulation of the transboundary Mara river basin. The
model study aims to characterise the hydrology in the pilot area. The study includes a thorough analysis of
rainfall, stage and flow data. Model preparation steps include the use of weighted-area rainfall estimation
methods, climate model data and empirical derivation of soil input parameters. Discharge calibration
methods include multi-site calibration, by making use of an alternative objective function statistic for the
commonly used Nash-Sutcliffe Efficiency (NSE) called the Kling-Gupta Efficiency (KGE). The literature study
targets previous flow and water quality studies done in tropical or wetland areas, thereby looking to see how
these studies adapted to hydrological modelling with SWAT in tropical or wetland areas, and why theses
adaptions were made. The literature research also includes a comparison of wetland processes in SWAT
with the physical, biological and chemical processes as described in previous studies.
The Mara river basin flow simulation gave a satisfactory model performance for two out of three calibration
sites, thereby being able to give preliminary outputs on water-balance and other flow characteristics. During
research, a number of model, knowledge and data gaps were found to be critical for better understanding
the hydrological and water quality system workings in the Lake Victoria and Mara river basin. From the
model and literature study it is concluded that several issues on data scarcity and hydrological model
processes in the tropics can be overcome. These do not necessarily decrease model performance or
uncertainty in the SWAT model. However, wetland processes are oversimplified in SWAT. Modification and
coupled SWAT models yet have not been able to provide an alternative to the default model that adequately
represents the main flow, sediment and nutrients processes and fluxes that are present in Mara’s wetlands.
Runoff modelling using hec hms for rural watershedEditorIJAERD
Due to climate change it is very essential to do hydrological modelling. Reliable models are essential for planning,
developmental works, prediction and safety of the population. Hydrological models are used to determine catchment
discharge/flow through an efficient way. HEC-HM (Hydrological engineering centre Hydrological modelling system) is
one of hydrological modelling tool developed by United States army corps of engineer (USACE) for event as well as for
continuous simulations. Models, especially continuous simulations are useful for future predictions of stream flow due to
land-use changes or extreme events phenomenon. In this study continuous hydrologic modellingwas carried out using
HEC HMS modelling tool.
Deficit and Constant Loss methods with Clark transform methods were selected. The calibrated model (period
1986-1988) was validated with data set of the period of 2009-2013. Study concluded that the model recommended and
can be used for stated River as decision support tool in the design and operation.
THE APPLICATION OF MATHEMATICAL MODELS IN MANAGEMENT OF AQUIFERamsjournal
Before feeling water -shortage crisis human has understood the importance of water From the
religious texts. Considering recent conditions of the world the water will replace most recent
boundaries, at future. Imamzadeh Jaafar plain is located 5 kilometers northeast of Gachsaran, south
of Kohgilooye and Boerahmad province. The plain has 61km 2 area extents and contains two,
alluvial and carbonate aquifers. These aquifers supply the water needs, agricultural, industrial and
domestic. Highly exploitation and transportation of groundwater resources, especially by National Oil
Company, caused highly drawdown in alluvial aquifer, 1.85m in a 5 years period from 1361 to
1365 as reported by Mahab Ghods Consulting Engineers. There are two artificial recharge
projects, 1 flood spreading system and 1 recharge ponds system, in the plain. To present the future
water resources management program the hydrogeological behaviors of the alluvial aquifer and the
effects of artificial recharge must be evaluated. edrock, hydrodynamic coefficients, topography, water
resources and were collected, field surveys were performed and required maps were prepared. Using
conceptual model and MODFLOW PMWIN code the mathematical model of the plain was
calibrated against water year 1380 -81 and then verified against water year 1384 - 85. The verified
model was used to predict future conditions of aquifer. The results implied the rapid response of
aquifer to precipitation due to high aquifer ransmissivity, positive water budget at year 1385
comparing year 65, change of direction of groundwater flow from plain outlet to the center of
plain in response to highly exploitation at the center of plain, water level in the wells located
downward the flood spreading system will raise as 1 to 6m and water level in t he wells located
downward the recharge pond system will lower as 1 to 4m.
A study confined to the lower tapi basin in Gujarat, India to find out the primary causes for 2006 floods in Surat city. The study involves collection of topographical data from the local geological survey organization, rainfall data from meteorological department of india and the application of HEC-HMS software from US Army corps of engineers to identify the primary cause of the runoff.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This study explains the use of remote sensing data for spatially distributed hydrological modeling using the MIKE-SHE software used in Tarim River Basin CHINA
Prof Graeme Dandy at the Landscape Science Cluster Seminar, May 2009pdalby
Professor Graeme Dandy from the University of Adelaide presenting on Optimisation of Water Management at the Landscape Science Cluster Seminar, May 2009
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
call for paper 2012, hard copy of journal, research paper publishing, where to publish research paper,
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
call for paper 2012, hard copy of journal, research paper publishing, where to publish research paper,
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Assessing the ability of SWAT as a water quality model in the Lake Victoria b...Timo Brussée
There is a need for a water quality model for use in the Lake Victoria basin countries in East-Africa. The
region is characterised by data scarcity, a tropical climate and riverine, lacustrine tidal wetlands which form
an important buffer to riverine pollution of the lake. These characteristics of the basin form a challenge for
water quality models. The objective is to state the strengths and weaknesses of a potential water quality
model under these challenging conditions. This objective is executed with the soil water assessment tool
(SWAT) in a catchment of the Lake Victoria Basin as pilot area. The pilot area of the Mara river basin is
hydrologically complex containing tropical and plantation forest, savanna, grasslands, bi-annual agriculture,
shrublands and wetlands. It has varied soil types and bi-annual rain seasons
The study consist of literature research and flow simulation of the transboundary Mara river basin. The
model study aims to characterise the hydrology in the pilot area. The study includes a thorough analysis of
rainfall, stage and flow data. Model preparation steps include the use of weighted-area rainfall estimation
methods, climate model data and empirical derivation of soil input parameters. Discharge calibration
methods include multi-site calibration, by making use of an alternative objective function statistic for the
commonly used Nash-Sutcliffe Efficiency (NSE) called the Kling-Gupta Efficiency (KGE). The literature study
targets previous flow and water quality studies done in tropical or wetland areas, thereby looking to see how
these studies adapted to hydrological modelling with SWAT in tropical or wetland areas, and why theses
adaptions were made. The literature research also includes a comparison of wetland processes in SWAT
with the physical, biological and chemical processes as described in previous studies.
The Mara river basin flow simulation gave a satisfactory model performance for two out of three calibration
sites, thereby being able to give preliminary outputs on water-balance and other flow characteristics. During
research, a number of model, knowledge and data gaps were found to be critical for better understanding
the hydrological and water quality system workings in the Lake Victoria and Mara river basin. From the
model and literature study it is concluded that several issues on data scarcity and hydrological model
processes in the tropics can be overcome. These do not necessarily decrease model performance or
uncertainty in the SWAT model. However, wetland processes are oversimplified in SWAT. Modification and
coupled SWAT models yet have not been able to provide an alternative to the default model that adequately
represents the main flow, sediment and nutrients processes and fluxes that are present in Mara’s wetlands.
Runoff modelling using hec hms for rural watershedEditorIJAERD
Due to climate change it is very essential to do hydrological modelling. Reliable models are essential for planning,
developmental works, prediction and safety of the population. Hydrological models are used to determine catchment
discharge/flow through an efficient way. HEC-HM (Hydrological engineering centre Hydrological modelling system) is
one of hydrological modelling tool developed by United States army corps of engineer (USACE) for event as well as for
continuous simulations. Models, especially continuous simulations are useful for future predictions of stream flow due to
land-use changes or extreme events phenomenon. In this study continuous hydrologic modellingwas carried out using
HEC HMS modelling tool.
Deficit and Constant Loss methods with Clark transform methods were selected. The calibrated model (period
1986-1988) was validated with data set of the period of 2009-2013. Study concluded that the model recommended and
can be used for stated River as decision support tool in the design and operation.
THE APPLICATION OF MATHEMATICAL MODELS IN MANAGEMENT OF AQUIFERamsjournal
Before feeling water -shortage crisis human has understood the importance of water From the
religious texts. Considering recent conditions of the world the water will replace most recent
boundaries, at future. Imamzadeh Jaafar plain is located 5 kilometers northeast of Gachsaran, south
of Kohgilooye and Boerahmad province. The plain has 61km 2 area extents and contains two,
alluvial and carbonate aquifers. These aquifers supply the water needs, agricultural, industrial and
domestic. Highly exploitation and transportation of groundwater resources, especially by National Oil
Company, caused highly drawdown in alluvial aquifer, 1.85m in a 5 years period from 1361 to
1365 as reported by Mahab Ghods Consulting Engineers. There are two artificial recharge
projects, 1 flood spreading system and 1 recharge ponds system, in the plain. To present the future
water resources management program the hydrogeological behaviors of the alluvial aquifer and the
effects of artificial recharge must be evaluated. edrock, hydrodynamic coefficients, topography, water
resources and were collected, field surveys were performed and required maps were prepared. Using
conceptual model and MODFLOW PMWIN code the mathematical model of the plain was
calibrated against water year 1380 -81 and then verified against water year 1384 - 85. The verified
model was used to predict future conditions of aquifer. The results implied the rapid response of
aquifer to precipitation due to high aquifer ransmissivity, positive water budget at year 1385
comparing year 65, change of direction of groundwater flow from plain outlet to the center of
plain in response to highly exploitation at the center of plain, water level in the wells located
downward the flood spreading system will raise as 1 to 6m and water level in t he wells located
downward the recharge pond system will lower as 1 to 4m.
A study confined to the lower tapi basin in Gujarat, India to find out the primary causes for 2006 floods in Surat city. The study involves collection of topographical data from the local geological survey organization, rainfall data from meteorological department of india and the application of HEC-HMS software from US Army corps of engineers to identify the primary cause of the runoff.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This study explains the use of remote sensing data for spatially distributed hydrological modeling using the MIKE-SHE software used in Tarim River Basin CHINA
Prof Graeme Dandy at the Landscape Science Cluster Seminar, May 2009pdalby
Professor Graeme Dandy from the University of Adelaide presenting on Optimisation of Water Management at the Landscape Science Cluster Seminar, May 2009
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
call for paper 2012, hard copy of journal, research paper publishing, where to publish research paper,
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
call for paper 2012, hard copy of journal, research paper publishing, where to publish research paper,
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
The Development of a Catchment Management Modelling System for the Googong Re...GavanThomas
A scenario assessment model to assist the end-user in determining priorities for a series of agreed management prescriptions that can be enacted through controls on existing landuse
MODEL OF WATER BALANCE BASED ON THE SYSTEM DYNAMICS IAEME Publication
This research intends to investigate the relation between cause and effect which influence the water availability and water need, and then to build a formulation as an effort of intervention with high leverage. The object of this research is Batam island that is part of the Riau islands province-Indonesia. This province has been remained as the national strategy area based on the Government Regulation No 26/ 2008 about the spatial plan of national area. The methodology consists of the system dynamics approach that can integrate the complex and persistence system in analyzing water balance. In the system dynamics, the behaviour patterns are generated by the water availability and water need with increasing time and by using the main asumption that every complex system is sourced on the causal structure that is forming the system. The result is as the model of water balance due to the system dynamics generally in Indonesia and especially in Batam island
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
A Novel Method for Prevention of Bandwidth Distributed Denial of Service AttacksIJERD Editor
Distributed Denial of Service (DDoS) Attacks became a massive threat to the Internet. Traditional
Architecture of internet is vulnerable to the attacks like DDoS. Attacker primarily acquire his army of Zombies,
then that army will be instructed by the Attacker that when to start an attack and on whom the attack should be
done. In this paper, different techniques which are used to perform DDoS Attacks, Tools that were used to
perform Attacks and Countermeasures in order to detect the attackers and eliminate the Bandwidth Distributed
Denial of Service attacks (B-DDoS) are reviewed. DDoS Attacks were done by using various Flooding
techniques which are used in DDoS attack.
The main purpose of this paper is to design an architecture which can reduce the Bandwidth
Distributed Denial of service Attack and make the victim site or server available for the normal users by
eliminating the zombie machines. Our Primary focus of this paper is to dispute how normal machines are
turning into zombies (Bots), how attack is been initiated, DDoS attack procedure and how an organization can
save their server from being a DDoS victim. In order to present this we implemented a simulated environment
with Cisco switches, Routers, Firewall, some virtual machines and some Attack tools to display a real DDoS
attack. By using Time scheduling, Resource Limiting, System log, Access Control List and some Modular
policy Framework we stopped the attack and identified the Attacker (Bot) machines
Hearing loss is one of the most common human impairments. It is estimated that by year 2015 more
than 700 million people will suffer mild deafness. Most can be helped by hearing aid devices depending on the
severity of their hearing loss. This paper describes the implementation and characterization details of a dual
channel transmitter front end (TFE) for digital hearing aid (DHA) applications that use novel micro
electromechanical- systems (MEMS) audio transducers and ultra-low power-scalable analog-to-digital
converters (ADCs), which enable a very-low form factor, energy-efficient implementation for next-generation
DHA. The contribution of the design is the implementation of the dual channel MEMS microphones and powerscalable
ADC system.
Influence of tensile behaviour of slab on the structural Behaviour of shear c...IJERD Editor
-A composite beam is composed of a steel beam and a slab connected by means of shear connectors
like studs installed on the top flange of the steel beam to form a structure behaving monolithically. This study
analyzes the effects of the tensile behavior of the slab on the structural behavior of the shear connection like slip
stiffness and maximum shear force in composite beams subjected to hogging moment. The results show that the
shear studs located in the crack-concentration zones due to large hogging moments sustain significantly smaller
shear force and slip stiffness than the other zones. Moreover, the reduction of the slip stiffness in the shear
connection appears also to be closely related to the change in the tensile strain of rebar according to the increase
of the load. Further experimental and analytical studies shall be conducted considering variables such as the
reinforcement ratio and the arrangement of shear connectors to achieve efficient design of the shear connection
in composite beams subjected to hogging moment.
Gold prospecting using Remote Sensing ‘A case study of Sudan’IJERD Editor
Gold has been extracted from northeast Africa for more than 5000 years, and this may be the first
place where the metal was extracted. The Arabian-Nubian Shield (ANS) is an exposure of Precambrian
crystalline rocks on the flanks of the Red Sea. The crystalline rocks are mostly Neoproterozoic in age. ANS
includes the nations of Israel, Jordan. Egypt, Saudi Arabia, Sudan, Eritrea, Ethiopia, Yemen, and Somalia.
Arabian Nubian Shield Consists of juvenile continental crest that formed between 900 550 Ma, when intra
oceanic arc welded together along ophiolite decorated arc. Primary Au mineralization probably developed in
association with the growth of intra oceanic arc and evolution of back arc. Multiple episodes of deformation
have obscured the primary metallogenic setting, but at least some of the deposits preserve evidence that they
originate as sea floor massive sulphide deposits.
The Red Sea Hills Region is a vast span of rugged, harsh and inhospitable sector of the Earth with
inimical moon-like terrain, nevertheless since ancient times it is famed to be an abode of gold and was a major
source of wealth for the Pharaohs of ancient Egypt. The Pharaohs old workings have been periodically
rediscovered through time. Recent endeavours by the Geological Research Authority of Sudan led to the
discovery of a score of occurrences with gold and massive sulphide mineralizations. In the nineties of the
previous century the Geological Research Authority of Sudan (GRAS) in cooperation with BRGM utilized
satellite data of Landsat TM using spectral ratio technique to map possible mineralized zones in the Red Sea
Hills of Sudan. The outcome of the study mapped a gossan type gold mineralization. Band ratio technique was
applied to Arbaat area and a signature of alteration zone was detected. The alteration zones are commonly
associated with mineralization. The alteration zones are commonly associated with mineralization. A filed check
confirmed the existence of stock work of gold bearing quartz in the alteration zone. Another type of gold
mineralization that was discovered using remote sensing is the gold associated with metachert in the Atmur
Desert.
Reducing Corrosion Rate by Welding DesignIJERD Editor
The paper addresses the importance of welding design to prevent corrosion at steel. Welding is
used to join pipe, profiles at bridges, spindle, and a lot more part of engineering construction. The
problems happened associated with welding are common issues in these fields, especially corrosion.
Corrosion can be reduced with many methods, they are painting, controlling humidity, and also good
welding design. In the research, it can be found that reducing residual stress on the welding can be
solved in corrosion rate reduction problem.
Preheating on 500oC and 600oC give better condition to reduce corosion rate than condition after
preheating 400oC. For all welding groove type, material with 500oC and 600oC preheating after 14 days
corrosion test is 0,5%-0,69% lost. Material with 400oC preheating after 14 days corrosion test is 0,57%-0,76%
lost.
Welding groove also influence corrosion rate. X and V type welding groove give better condition to reduce
corrosion rate than use 1/2V and 1/2 X welding groove. After 14 days corrosion test, the samples with
X welding groove type is 0,5%-0,57% lost. The samples with V welding groove after 14 days corrosion test is
0,51%-0,59% lost. The samples with 1/2V and 1/2X welding groove after 14 days corrosion test is 0,58%-
0,71% lost.
Router 1X3 – RTL Design and VerificationIJERD Editor
Routing is the process of moving a packet of data from source to destination and enables messages
to pass from one computer to another and eventually reach the target machine. A router is a networking device
that forwards data packets between computer networks. It is connected to two or more data lines from different
networks (as opposed to a network switch, which connects data lines from one single network). This paper,
mainly emphasizes upon the study of router device, it‟s top level architecture, and how various sub-modules of
router i.e. Register, FIFO, FSM and Synchronizer are synthesized, and simulated and finally connected to its top
module.
Active Power Exchange in Distributed Power-Flow Controller (DPFC) At Third Ha...IJERD Editor
This paper presents a component within the flexible ac-transmission system (FACTS) family, called
distributed power-flow controller (DPFC). The DPFC is derived from the unified power-flow controller (UPFC)
with an eliminated common dc link. The DPFC has the same control capabilities as the UPFC, which comprise
the adjustment of the line impedance, the transmission angle, and the bus voltage. The active power exchange
between the shunt and series converters, which is through the common dc link in the UPFC, is now through the
transmission lines at the third-harmonic frequency. DPFC multiple small-size single-phase converters which
reduces the cost of equipment, no voltage isolation between phases, increases redundancy and there by
reliability increases. The principle and analysis of the DPFC are presented in this paper and the corresponding
simulation results that are carried out on a scaled prototype are also shown.
Mitigation of Voltage Sag/Swell with Fuzzy Control Reduced Rating DVRIJERD Editor
Power quality has been an issue that is becoming increasingly pivotal in industrial electricity
consumers point of view in recent times. Modern industries employ Sensitive power electronic equipments,
control devices and non-linear loads as part of automated processes to increase energy efficiency and
productivity. Voltage disturbances are the most common power quality problem due to this the use of a large
numbers of sophisticated and sensitive electronic equipment in industrial systems is increased. This paper
discusses the design and simulation of dynamic voltage restorer for improvement of power quality and
reduce the harmonics distortion of sensitive loads. Power quality problem is occurring at non-standard
voltage, current and frequency. Electronic devices are very sensitive loads. In power system voltage sag,
swell, flicker and harmonics are some of the problem to the sensitive load. The compensation capability
of a DVR depends primarily on the maximum voltage injection ability and the amount of stored
energy available within the restorer. This device is connected in series with the distribution feeder at
medium voltage. A fuzzy logic control is used to produce the gate pulses for control circuit of DVR and the
circuit is simulated by using MATLAB/SIMULINK software.
Study on the Fused Deposition Modelling In Additive ManufacturingIJERD Editor
Additive manufacturing process, also popularly known as 3-D printing, is a process where a product
is created in a succession of layers. It is based on a novel materials incremental manufacturing philosophy.
Unlike conventional manufacturing processes where material is removed from a given work price to derive the
final shape of a product, 3-D printing develops the product from scratch thus obviating the necessity to cut away
materials. This prevents wastage of raw materials. Commonly used raw materials for the process are ABS
plastic, PLA and nylon. Recently the use of gold, bronze and wood has also been implemented. The complexity
factor of this process is 0% as in any object of any shape and size can be manufactured.
Spyware triggering system by particular string valueIJERD Editor
This computer programme can be used for good and bad purpose in hacking or in any general
purpose. We can say it is next step for hacking techniques such as keylogger and spyware. Once in this system if
user or hacker store particular string as a input after that software continually compare typing activity of user
with that stored string and if it is match then launch spyware programme.
A Blind Steganalysis on JPEG Gray Level Image Based on Statistical Features a...IJERD Editor
This paper presents a blind steganalysis technique to effectively attack the JPEG steganographic
schemes i.e. Jsteg, F5, Outguess and DWT Based. The proposed method exploits the correlations between
block-DCTcoefficients from intra-block and inter-block relation and the statistical moments of characteristic
functions of the test image is selected as features. The features are extracted from the BDCT JPEG 2-array.
Support Vector Machine with cross-validation is implemented for the classification.The proposed scheme gives
improved outcome in attacking.
Secure Image Transmission for Cloud Storage System Using Hybrid SchemeIJERD Editor
- Data over the cloud is transferred or transmitted between servers and users. Privacy of that
data is very important as it belongs to personal information. If data get hacked by the hacker, can be
used to defame a person’s social data. Sometimes delay are held during data transmission. i.e. Mobile
communication, bandwidth is low. Hence compression algorithms are proposed for fast and efficient
transmission, encryption is used for security purposes and blurring is used by providing additional
layers of security. These algorithms are hybridized for having a robust and efficient security and
transmission over cloud storage system.
Application of Buckley-Leverett Equation in Modeling the Radius of Invasion i...IJERD Editor
A thorough review of existing literature indicates that the Buckley-Leverett equation only analyzes
waterflood practices directly without any adjustments on real reservoir scenarios. By doing so, quite a number
of errors are introduced into these analyses. Also, for most waterflood scenarios, a radial investigation is more
appropriate than a simplified linear system. This study investigates the adoption of the Buckley-Leverett
equation to estimate the radius invasion of the displacing fluid during waterflooding. The model is also adopted
for a Microbial flood and a comparative analysis is conducted for both waterflooding and microbial flooding.
Results shown from the analysis doesn’t only records a success in determining the radial distance of the leading
edge of water during the flooding process, but also gives a clearer understanding of the applicability of
microbes to enhance oil production through in-situ production of bio-products like bio surfactans, biogenic
gases, bio acids etc.
Gesture Gaming on the World Wide Web Using an Ordinary Web CameraIJERD Editor
- Gesture gaming is a method by which users having a laptop/pc/x-box play games using natural or
bodily gestures. This paper presents a way of playing free flash games on the internet using an ordinary webcam
with the help of open source technologies. Emphasis in human activity recognition is given on the pose
estimation and the consistency in the pose of the player. These are estimated with the help of an ordinary web
camera having different resolutions from VGA to 20mps. Our work involved giving a 10 second documentary to
the user on how to play a particular game using gestures and what are the various kinds of gestures that can be
performed in front of the system. The initial inputs of the RGB values for the gesture component is obtained by
instructing the user to place his component in a red box in about 10 seconds after the short documentary before
the game is finished. Later the system opens the concerned game on the internet on popular flash game sites like
miniclip, games arcade, GameStop etc and loads the game clicking at various places and brings the state to a
place where the user is to perform only gestures to start playing the game. At any point of time the user can call
off the game by hitting the esc key and the program will release all of the controls and return to the desktop. It
was noted that the results obtained using an ordinary webcam matched that of the Kinect and the users could
relive the gaming experience of the free flash games on the net. Therefore effective in game advertising could
also be achieved thus resulting in a disruptive growth to the advertising firms.
Hardware Analysis of Resonant Frequency Converter Using Isolated Circuits And...IJERD Editor
-LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region[5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits.
Simulated Analysis of Resonant Frequency Converter Using Different Tank Circu...IJERD Editor
LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region [5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits. The supported simulation
is done through PSIM 6.0 software tool
Amateurs Radio operator, also known as HAM communicates with other HAMs through Radio
waves. Wireless communication in which Moon is used as natural satellite is called Moon-bounce or EME
(Earth -Moon-Earth) technique. Long distance communication (DXing) using Very High Frequency (VHF)
operated amateur HAM radio was difficult. Even with the modest setup having good transceiver, power
amplifier and high gain antenna with high directivity, VHF DXing is possible. Generally 2X11 YAGI antenna
along with rotor to set horizontal and vertical angle is used. Moon tracking software gives exact location,
visibility of Moon at both the stations and other vital data to acquire real time position of moon.
“MS-Extractor: An Innovative Approach to Extract Microsatellites on „Y‟ Chrom...IJERD Editor
Simple Sequence Repeats (SSR), also known as Microsatellites, have been extensively used as
molecular markers due to their abundance and high degree of polymorphism. The nucleotide sequences of
polymorphic forms of the same gene should be 99.9% identical. So, Microsatellites extraction from the Gene is
crucial. However, Microsatellites repeat count is compared, if they differ largely, he has some disorder. The Y
chromosome likely contains 50 to 60 genes that provide instructions for making proteins. Because only males
have the Y chromosome, the genes on this chromosome tend to be involved in male sex determination and
development. Several Microsatellite Extractors exist and they fail to extract microsatellites on large data sets of
giga bytes and tera bytes in size. The proposed tool “MS-Extractor: An Innovative Approach to extract
Microsatellites on „Y‟ Chromosome” can extract both Perfect as well as Imperfect Microsatellites from large
data sets of human genome „Y‟. The proposed system uses string matching with sliding window approach to
locate Microsatellites and extracts them.
Importance of Measurements in Smart GridIJERD Editor
- The need to get reliable supply, independence from fossil fuels, and capability to provide clean
energy at a fixed and lower cost, the existing power grid structure is transforming into Smart Grid. The
development of a smart energy distribution grid is a current goal of many nations. A Smart Grid should have
new capabilities such as self-healing, high reliability, energy management, and real-time pricing. This new era
of smart future grid will lead to major changes in existing technologies at generation, transmission and
distribution levels. The incorporation of renewable energy resources and distribution generators in the existing
grid will increase the complexity, optimization problems and instability of the system. This will lead to a
paradigm shift in the instrumentation and control requirements for Smart Grids for high quality, stable and
reliable electricity supply of power. The monitoring of the grid system state and stability relies on the
availability of reliable measurement of data. In this paper the measurement areas that highlight new
measurement challenges, development of the Smart Meters and the critical parameters of electric energy to be
monitored for improving the reliability of power systems has been discussed.
Study of Macro level Properties of SCC using GGBS and Lime stone powderIJERD Editor
One of the major environmental concerns is the disposal of the waste materials and utilization of
industrial by products. Lime stone quarries will produce millions of tons waste dust powder every year. Having
considerable high degree of fineness in comparision to cement this material may be utilized as a partial
replacement to cement. For this purpose an experiment is conducted to investigate the possibility of using lime
stone powder in the production of SCC with combined use GGBS and how it affects the fresh and mechanical
properties of SCC. First SCC is made by replacing cement with GGBS in percentages like 10, 20, 30, 40, 50 and
by taking the optimum mix with GGBS lime stone powder is blended to mix in percentages like 5, 10, 15, 20 as
a partial replacement to cement. Test results shows that the SCC mix with combination of 30% GGBS and 15%
limestone powder gives maximum compressive strength and fresh properties are also in the limits prescribed by
the EFNARC.
Study of Macro level Properties of SCC using GGBS and Lime stone powder
Welcome to International Journal of Engineering Research and Development (IJERD)
1. International Journal of Engineering Research and Development
e-ISSN: 2278-067X, p-ISSN : 2278-800X, www.ijerd.com
Volume 4, Issue 10 (November 2012), PP. 30-37
An Overview of Reservoir Systems Operation Techniques
Azhar Husain
Assistant Professor, Department of Civil Engineering, Jamia Millia Islamia (Central University), New Delhi
Abstract:-A review of application of various optimization techniques to operation of multi-reservoir systems has
been presented. Operation of reservoirs, often for conflicting purposes, is a daunting task. . The solution to the
problem is difficult because of the large number of variables involved, the non-linearity of system dynamics, the
stochastic nature of future inflows, and other uncertainties of the system. The uncertainty associated with reservoir
operations is further increased due to the ongoing hydrological impacts of climate change. Traditionally, reservoir
systems operation has been carried out using optimization techniques such as linear programming and dynamic
programming. Linear programming cannot be applied when either the objective function or the constraints become
non-linear. Dynamic programming, however, becomes computationally bounded on problems of moderate size
and complexity. Therefore, various artificial intelligence techniques such as genetic algorithms, ant-colony
optimization, and fuzzy logic are increasingly being employed to solve multi-reservoir operation problems. A
large number of application of traditional as well as artificial intelligence techniques have been described in the
present paper.
Keywords: - Reservoir, Optimization, Optimal, Linear, Review, Dynamic
I. INTRODUCTION
India has several reservoirs that play a significant role in the progress and development of the country. Most of the
reservoirs serve multiple purposes such as flood control, hydropower generation, water supply, navigation, and restoration.
In recent years, the problem of ineffective operation of existing reservoirs using outdated technology and highly subjective
management practices has been repeatedly indicated by many specialists (e.g. Guariso et al., 1986; Oliveira and Loucks,
1997; Chen, 2003; John, 2004). The situation of excess water in the rainy season and scarcity in the dry season poses
significant challenges to effective reservoir operation. Many reservoirs in India are water-deficient in the dry season, but are
threatened by dam-break disasters in the flood season. Additional uncertainty in reservoir operations is introduced due to
global climate change as well as economic activities in the river basin. Due to changes of hydro-meteorological conditions
and shifting goals of water requirements from one region to the other, each reservoir has a different set of operation rules.
Operation of reservoirs is a complex problem that involves many decision variables, multiple objectives as well as
considerable risk and uncertainty (Oliveira and Loucks, 1997).
Reservoirs are often required to be operated for conflicting objectives thereby leading to significant challenges for
operators when making operational decisions. Traditionally, reservoir operation is based on heuristic procedures, embracing
rule curves and subjective judgements by the operator. This provides general operation strategies for reservoir releases
according to the current reservoir level, hydrological conditions, water demands and the time of the year. Established rule
curves, however, do not allow a fine-tuning (and hence optimisation) of the operations in response to changes in the
prevailing conditions. Therefore, it would-be valuable to establish an analytic and more systematic approach to reservoir
operation, based not only on traditional probabilistic/stochastic analysis, but also on the information and prediction of
extreme hydrologic events and advanced computational technology in order to increase the reservoir's efficiency for
balancing the demands from the different users.
II. MATHEMATICAL PROGRAMMING TECHNIQUES
Optimising the economic benefits of water resource systems is a classical and persistent problem. The solution to
the problem is difficult because of the large number of variables involved, the non-linearity of system dynamics, the
stochastic nature of future inflows, and other uncertainties of the system. Nevertheless, a number of mathematical
programming techniques have been developed to aid derivation of optimal operating strategies for water resource systems.
Most of these techniques perform satisfactorily for the problems they are developed for. A generic methodology that can
handle problems in their general form has not yet been identified, however. During the last three decades, one of the most
important advances made in the field of water resources engineering has been the development of optimisation techniques
for planning, design and management of complex water resource systems. The recent rapid increase in computer technology
has made the development of sophisticated mathematical models for the analysis of water resource systems possible. These
models are increasingly being used by system managers to determine decision alternatives which are optimal in some
defined sense. The optimisation of reservoir systems operation usually involves the search through large decision spaces for
optimal parameter sets. Often, the decision space is too large for a complete search. This has motivated the development of
various optimisation procedures. However, despite the extensive research carried out in the last three decades, reservoir
control still remains an active research field.
Most optimisation models are based on some type of mathematical programming technique. Many successful
applications of these techniques to reservoir operation studies have been reported in the literature, but no universally proven
technique exists. Excellent treatment of these techniques can be found in the works by Loucks et al. (1981) and Mays and
30
2. An Overview of Reservoir Systems Operation Techniques
Tung (1992). A survey of dynamic programming (DP) models applied to water resources planning problems was presented
by Yakowitz (1982). The application of various optimisation models to reservoir operation problems has been reviewed by
Simonovic (1992) and Wurbs (1993). Yeh (1985) provides an excellent state-of-the-art review of reservoir management and
operation models. According to Yeh (1985), the techniques being commonly used by the researchers can be broadly
classified as follows:
1. Linear programming (LP)
2. Non-linear programming (NLP)
3. Dynamic programming (DP) including
4. Discrete differential DP (DDDP), differential DP (DDP), successive approximation DP (SADP), and stochastic DP
(SDP)
5. Genetic algorithms
6. Simulation
1. Linear Programming
In a problem where all the objective and constraint functions are linear, LP can be used in the optimisation of
reservoir systems. It has been one of the most widely used techniques in water resources management due to its simplicity
and adaptability.
A typical LP model is Minimize or maximize Z C T X
Subject to AX b
where X 0 is a n dimensional vector of decision variables, C is a n dimensional vector of objective function coefficients;
b is a m dimensional vector of right hand side of above equation; A is a m n matrix of constraint coefficients; and T
represents the matrix transpose operation.
Dorfman (1962) demonstrated the application of LP to a water resource problem with three versions of a model,
each with increasing complexity. The objective was to maximise the economic benefits of water use while satisfying the
constraints of the problem. In all the three versions, both storage capacities and target releases were treated as decision
variables. The first version of model involved a simple LP application to a simplified river basin planning problem. In the
second version, critical period hydrology was used. In the third version, the model treats inflows stochastically. Gilbert and
Shane (1982) describe a model called HYDROSIM used to simulate the Tennessee Valley Authority reservoir system based
on established operating strategies. The model employed LP to compute reservoir storages, and hydropower generation for
each period of operating horizon. Palmer and Holmes (1988) incorporated a LP model in the Seattle Water Department
integrated drought-management expert system. The model was used to determine optimal operating policies and system
yield based upon the objectives of maximising the yield, and minimising the economic losses associated with deficits from a
specified target.
Randall et al. (1990) used LP to study the operation, during drought, of a water resource system consisting of
multiple reservoirs, groundwater, treatment plants, and distribution facilities. The objectives was to maximise the net
revenues, which were the difference between the cost of production and the selling price of water; maximise reliability,
expressed as the minimum of the ratios of consumption to demand for each water use deficit; maximise reservoir storage at
the end of the operating horizon; and maximise the minimum flows in the streams. Crawley and Dandy (1993) used LP to
develop a planning and operational model for the Adelaide headworks system in South Australia. The objective was to
determine optimal sequences of pumping and transfers for the system so as to minimise pumping cost while maintaining a
satisfactory level of reliability within the system. Martin (1995) describe an optimisation procedure based on LP to maximise
the power generation over a 24-hr period from the Highland Lakes of Lower Colorado river in Texas.The application of LP
requires the linearization of constraints and of the objective function, which for most of the practical reservoir systems are
non-linear functions. This limits the application of LP to problems with linear functions. Non-linear functions can be
approximated by linear functions, and successive LP (SLP) can be used to approximate the solutions. Grygier and Stedinger
(1985) and Hiew (1987) describe the application of SLP, among many other techniques, to multi reservoir optimisation
problems. Reznicek and Simonovic (1990) describes the application of SLP to Manitoba Hydro system in Canada. The
objective was to maximise the power production from the system. Since the power was not linearly related to the release,
Taylors series expansion was used to linearise the power function. Such simplification may, however, lead to reduction in
the value of the optimisation results.
2. Non-linear Programming
NLP technique can be applied where either the objective function or constraints are non-linear. NLP can
effectively handle a non-separable objective function and non-linear constraints. A general NLP problem can be expressed in
the form
Minimise F f ( x1 , x2 ,..., xn )
subject to gi ( x) 0 i = 1, m
where x j x j x j j = 1, n
in which F is to be minimised subject to m constraints expressed by function g(x), n is the number of decision variables, and
equation Error! Reference source not found. is a bound constraint for the jth decision variable x j with xj and xj being the
lower and upper bounds, respectively.
31
3. An Overview of Reservoir Systems Operation Techniques
NLP has not been very popular due to the computational complexity of the approach for multi reservoir systems
optimisation. Lee and Waziruddin (1970) applied NLP to a theoretical system of three reservoirs in series with the objective
of maximising a non-linear function of irrigation releases and storages in the reservoirs. Applications of NLP have also been
reported by Simonovic and Marino (1980), Rosenthal (1981), and Guibert et al. (1990). A special case of NLP is quadratic
programming (QP) where the degree of various terms in the objective function is 2, 1, or 0. A quadratic optimisation model
for the California Central Valley Project (CCVP) has been presented by Marino and Loaiciga (1985). The model was
compared with an LP model, and it was found that a significant increase in the total energy production could be obtained
using the QP model. Diaz and Fontane (1989) applied sequential QP (SQP) to determine optimal economic returns from
hydropower generation for a multi reservoir system in Argentina. The SQP approach was found to be superior to SLP in
terms of the execution time and the value of the objection function achieved. Wardlaw et al. (1997) used QP to solve water
allocation problem to the Lower Ayung irrigation system on the island of Bali in Indonesia. The objective was to maximise
crop production while maintaining equity in water supply between irrigation schemes and the irrigation blocks within the
schemes.
A large number of NLP software packages are commercially available. Most commonly used packages include
GAMS, INRIA, LINDO, LINGO, Mathworks, NAG and OSL. For multiple reservoir systems, the number of constraints is
large because they deal with similar subsystems repeated in time or location. Therefore, NLP requires large amount of
storage and execution time when compared to other methods limiting its applicability to large systems (Yeh 1985). The use
of NLP is further limited to problems that are smooth and continuous because it requires the calculation of derivatives for its
search procedure.
3. Dynamic Programming
DP (Bellman 1957) is the most commonly used method for the optimisation of reservoir systems as these are
characterised by large number of non-linear and stochastic features that can be translated into a DP formulation. DP is an
enumeration procedure used to determine the combinations of decisions that optimises overall system effectiveness as
measured by a criterion function. It is capable of treating non-convex, non-linear and discontinuous objective and constraint
functions, and this is the greatest advantage of DP. Constraints on both decision and state variables introduce no difficulties.
In fact, the constraints speed up the computational procedure. The key feature of DP application is that it is usually identified
as serially or progressively directed for operational or planning problems, respectively. The operation of reservoirs is a
multistage decision process and DP is particularly suited to such problems. The problem is divided into stages with a
decision required at each stage. The stages usually represent different points in time and each stage should have a finite
number of states associated with it. In reservoir operation studies, the state usually represents the amount of water in the
reservoir at a given stage. If DP is used for determination of reservoir releases, these form the decision variables. The stage
to stage transformation is carried out by the continuity equation subject to constraints on storages and releases. The recursive
equation of DP can be written as
Fn ( sn ) max [Vn ( sn , d n ) Fn1 ( sn1 )]
where sn is the state variable, dn is the decision variable, Vn (sn, dn) is the objective function value, Fn ( s n ) is the
cumulative return at stage n with F0 ( s 0 ) known, and s n 1 g ( s n , d n ) is the stage to stage transformation function.
DP has been successfully used by many researchers for optimisation of water resource systems. Hall and Buras
(1961) were the first to propose the application of DP to determine optimal returns from reservoir systems. Young (1967)
developed optimal operating rules for a single reservoir using DP. A series of synthetically generated inflow sequences were
used to derive a set of optimal release trajectories. These trajectories were then related to various system variables through
regression analysis. As a result, an operating rule expressed as a function of a set of system variables was obtained. Allen
and Bridgeman (1986) used DP for optimal scheduling of hydroelectric power. Applications of DP to reservoir operation
problems have also been reported by Opricovic and Djordjevic (1976) and Collins (1977). Extensive review of DP
applications to reservoir systems can be found in the works by Yakowitz (1982) and Yeh (1985).
The disadvantages associated with DP are the huge requirements in terms of computer memory and execution time.
The approach breaks down on the problems of moderate size and complexity, suffering from a malady labelled the „curse of
dimensionality‟ by its creator Bellman (1957). For a system with n state variables and k levels of discretization, there exists
kn combinations that need to be evaluated at each stage of analysis. The usefulness of DP when applied to multiple reservoir
systems is therefore limited by the “curse of dimensionality” which is a strong function of the number of state variables and
the levels of discretization used. The application of DP to problems with more than two or three state variables still remains
a challenging task on present day computers. A traditional and simplistic procedure for reducing computational effort in DP
is the iterative coarse grid method. The problem is first solved using a coarser discretization of the state variables. Based
upon the resulting solution, revised bounds on the state variables are defined and the grid size is then reduced. The iterative
procedure is repeated until the grid size has been reduced to a desired precision. The algorithm is stopped when no further
improvement in the value of the objective function can be obtained. This procedure, however, cannot guarantee a global
optimum. Besides, it also does not resolve the dimensionality problem.
To overcome the dimensionality problem imposed by DP to some extent, use of LP in combination with DP has
been reported by many researchers. In a combined LP-DP procedure, the stage to stage optimisation is carried out by LP, and
DP is used for determining optimal policy over a number of stages. Becker and Yeh (1974) applied a combined LP-DP
approach to optimal real time operations associated with CCVP. The LP minimised the loss in potential energy of the stored
water in the reservoirs resulting from any release policy in each period. The multiperiod optimisation was carried out by
embedding the LP solutions in a deterministic forward DP. The LP-DP combination has also been used by Takeuchi and
Moreau (1974), Becker et al. (1976), Yeh et al. (1979), Yeh and Becker (1982), and Marino and Mohammadi (1983). The
32
4. An Overview of Reservoir Systems Operation Techniques
non-linearities are handled using an iterative technique, such as SLP. Grygier and Stedinger (1985) describe the application
of SLP, an optimal control algorithm (Pontryagin et al. 1962), and a combined LP-DP algorithm to a multi reservoir system.
The optimal control algorithm is based on Pontryagin‟s maximum principle (Pontryagin et al. 1962) and involves the
solution of Kuhn-Tucker necessary conditions of optimality. The optimal control algorithm for the problem solved by
Grygier and Stedinger (1985) executed five times faster than the SLP. The LP-DP algorithm took longer to execute and
produced comparatively inferior solutions.
4. Discrete Differential Dynamic Programming
Many variants of DP have been developed over time to alleviate the problems of dimensionality. Notable among
these are incremental dynamic programming (IDP), DPSA and DDDP. These are iterative techniques and start with the
assumption of a trial trajectory. DDDP is specifically designed to overcome the dimensionality problem posed by DP. The
technique uses the same recursive equation as DP to search among the discrete states in the state-stage domain. Instead of
searching over the entire state-stage domain for the optimum, the optimisation is constrained only to a part of the state-stage
domain saving computer time and memory. The method starts with the selection of a trial state trajectory satisfying the
boundary conditions. Several states, located in the neighbourhood of a trial trajectory can be introduced to form a band
called a corridor around the trial trajectory. The traditional DP approach is applied to optimise within the defined corridor.
Consequently, an improved trajectory is obtained which is adopted as the new trajectory to form a new corridor. This process
of corridor formation, optimisation with respect to the states within the corridor and trace back to obtain an improved
trajectory for the system is called an iteration. The procedure is repeated for a number of iterations until no further
improvement in the value of the objective function can be obtained.Larson (1968) obtained the solution to the four reservoir
problem using IDP. Hall et al. (1969) used a different version of IDP and solved a two reservoir system. The major
difference between the two versions is that the time interval used in the computation is variable in the former and fixed in the
latter. Another version called DDDP was developed by Heidari et al. (1971) which could be seen as a generalisation of IDP.
They solved the four reservoir problem formulated by Larson (1968). The terms IDP and DDDP have been used
interchangeably in water resources applications. In the standard IDP of Larson (1968), the number of discretizations is
limited to three per state variable. The computational burden and memory requirements for such an approach is a function 3 n,
where n is the number of state variables. IDP does overcome the dimensionality problem to a large extent but requires
stringent conditions to be satisfied for implementing the procedure. The IDP method require that there must exist a function
g t ( s t , s t 1 ) such that for every pair of states st and st+1,
g t ( s t , s t 1 ) rt
where rt is the release in time step t such that s t 1 f t ( s t , rt )
In IDP, an optimal solution can only be obtained if all the states in the corridor are accessible from one stage to
another. When the optimisation is restricted to three states in each stage, the above condition may not be satisfied and IDP
may converge to a non-optimal solution. When the optimisation is carried out over the entire decision space, the method
becomes time consuming and memory requirements are also high but the likelihood of locating the optimum is increased.
Turgeon (1982) demonstrated that IDP may lead to non optimal solutions. Suggestions were then made to adjust the
increment sizes in each stage to obtain the desired results. The choice of initial trial trajectory is vital for good convergence
in all iterative algorithms. For complex systems, the determination of feasible trial state trajectories is not a trivial task.
Another approach which overcomes the dimensionality problem is the DP successive approximation technique
(DPSA). The technique was first proposed by Larson (1968). Trott and Yeh (1973) used successive approximation technique
in combination with IDP. The original multiple state variable DP problem was decomposed in a series of sub-problems of
one state variable. To demonstrate the technique, a six reservoir problem was solved. The optimisations were carried out
with respect to a single reservoir while keeping the states in the other reservoirs fixed. The procedure is repeated for other
reservoirs until the convergence criteria is satisfied. Successive approximation is one-at-a-time optimisation technique and
its common drawback is convergence to a local optimum. Extension to successive approximation technique has been
reported by Nopmongcol and Askew (1976), who suggested higher level combinations, such as two or three-at-a-time
combinations. The technique was demonstrated through application to the four reservoir problem.The requirement that the
state variables be discretized is a major cause of computational complexity. Jacobson and Mayne (1970) developed
differential DP (DDP) for multi state problems. Murray and Yakowitz (1979) applied DDP to multi reservoir control
problems. The important feature of the technique is that discretization of state and decision space is not required. The
method requires a quadratic approximation of the objective function. Application of the method to a ten reservoir problem by
Murray and Yakowitz (1979) has demonstrated its effectiveness. Murray and Yakowitz (1979) also solved the four reservoir
problem using DDP and showed that the global optimum was obtained in much lesser number of iterations than in DDDP.
Application of DDP to estuary management has been reported by Li and Mays (1995). However, the technique requires that
the objective function is differentiable and that constraints are linear Howson and Sancho (1975) developed a progressive
optimality algorithm (POA) for multistate problems. Turgeon (1981b) applied the algorithm to an example system consisting
of four reservoirs in series. The most promising aspect of the approach is that the state variables do not have to be discretized.
The algorithm, however, required 823 iterations to converge to an optimal solution for the simple example considered. The
approach has merit in that it overcomes the dimensionality problem. A binary state DP algorithm has been developed by
Ozden (1984) in which the optimisation is constrained within a subset consisting of only two states at each stage. One of the
states is the component of the optimal trajectory found in the previous iteration. The second value is defined according to the
shifting direction of the optimal trajectory in the state space at previous iteration. This procedure differs from DDDP in the
manner in which the states are chosen for next iteration.
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5. An Overview of Reservoir Systems Operation Techniques
5. Genetic Algorithms
Despite intensive research carried out during the last three decades, a generic technique for the optimisation of
complex systems is yet to be identified. In recent years, genetic algorithms (GAs) have gained growing popularity among
researchers as a robust and general optimisation technique. A genetic algorithm is a technique in which a population of
abstract representations of candidate solutions to an optimisation problem are stochastically selected, recombined, mutated,
and then either eliminated or retained, based on their relative fitness. The approach has been successfully applied to a wide
variety of problems from diverse fields. The results of employment of GAs to various difficult optimisation problems have
indicated considerable potential.In the “Origin of Species”, Darwin (1859) stated the theory of natural evolution. Over many
generations, biological organisms evolve according to the principles of natural selection like the “survival of the fittest” to
reach some remarkable forms of accomplishment. In nature, individuals in a population have to compete with each other for
vital resources such as food and shelter. Because of this, the least adaptable individuals are eliminated from the population
while the fittest or the most adaptable individuals reproduce a larger number of offsprings. During reproduction, a
recombination of the good characteristics of each parent can produce offsprings whose fitness is greater than either of the
parents. After a number of generations, the species evolve spontaneously to become more and more adapted to their
environment. Holland (1975) developed this idea in “Adaptation in Natural and Artificial Systems” and laid down the first
GA. Since then, GAs have developed into a powerful technique for identifying optimal solutions to complex problems.
Excellent introductions to GAs are given by Goldberg (1989) and by Michalewicz (1992). Application of GAs to many
complex real problems can be found in the works by Davis (1991), Michalewicz (1992), and Dasgupta and Michalewicz
(1997). GAs are a class of artificial intelligence techniques based on the mechanics of natural selection and natural genetics
directly derived from the theory of natural evolution. GAs simulate mechanisms of population genetics and natural rules of
survival in pursuit of the ideas of adaptation and use a vocabulary borrowed from natural genetics. To surpass the traditional
methods, GAs must differ in some very fundamental ways. Goldberg (1989) identifies the following as the significant
differences between GAs and more traditional optimisation methods. GAs
work with a coding of the parameter set, not the parameter themselves;
search from a population of points, not a single point;
use objective function information, not derivatives or other auxiliary knowledge;
use probabilistic transition rules, not deterministic rules.
A GA is a robust method of searching for the optimum solution to a complex problem. It is basically an automated
intelligent approach to find a solution to a problem, although it may not necessarily lead to the best possible one. Consider an
optimisation problem with 100 parameters with each parameter taking on 100 values. The number of possible combinations
of parameters would be 100100. Since the search space is huge, it is not possible to quickly enumerate all the possible
solutions. In the past, such problems were tackled by making intelligent guesses about the values of the parameters and a
solution obtained by trial and error procedure. But with the advent of GAs, a fairly good solution to such problems can be
found within an affordable computing time.A GA represents a solution using strings of variables that represent the problem.
In biological terminology such strings are also known as chromosomes or individuals. Coding components of possible
solutions into a chromosome is the first part of a GA formulation. Each chromosome is a potential solution and comprises of
sub-strings or genes representing decision variables which can be used to evaluate the objective function of the problem. The
fitness of a chromosome as a candidate solution to a problem is an expression of the value of the objective function
represented by it. It is obtained using an evaluation function, which is a link between the GA and the problem to be solved.
The fitness is also a function of problem constraints and may be modified through the introduction of penalties when
constraints are not satisfied.A GA starts with a set of chromosomes representing potential solutions to the problem. These
chromosomes are combined through genetic operators to produce successively fitter chromosomes. The genetic operators
used in the reproductive process are selection, crossover, and mutation. Combination is achieved through the crossover of
pieces of genetic material between selected chromosomes. Chromosomes in the population with high fitness values have
high probability of being selected for combination with other chromosomes of high fitness. Mutation allows for the random
mutations of bits of information in individual genes. The fitness of chromosomes should progressively improve over the
generations. The whole GA procedure is allowed to evolve for a sufficient number of generations, and at the end of the
evolution process a chromosome representing an optimal (or a near optimal) solution to the problem should be obtained.
6. Simulation
Simulation is a modelling technique used to approximate the behaviour of a system on a computer, representing all
the characteristics of the system largely by a mathematical or algebraic description. Simulation models provide the response
of the system to certain inputs, which include decision rules that allow the decision makers to test the performance of
existing systems or a new system without actually building it. A typical simulation model for a water resources system is
simply a model that simulates the interval-by-interval operation of the system with specified inflows at all locations during
each interval, specified system characteristics and specified operating rules.Optimisation models aim to identify optimum
decisions for system operation that maximises certain given objectives while satisfying the system constraints. On the other
hand, simulation models are used to explore only a finite number of decision alternatives so that the optimum solution may
not necessarily be achieved. However, many simulation models now involve a certain degree of optimisation and the
difference between the optimisation and simulation models is becoming less distinct. For a given operating criteria, the
performance of a reservoir system may be evaluated by analysing the computed time sequence of levels, storage, discharges,
hydropower etc. The procedure can be repeated for a number of inflow sequences to arrive at a statistical measure of the
system.Simulation models have been routinely applied for many years by water resource development agencies. Yeh (1985)
and Wurb (1993) present reviews of a number of such models. An excellent treatment of the subject of computer simulation
in hydrology has been provided by Fleming (1975). A total of 19 simulation models have been presented in the text. The
34
6. An Overview of Reservoir Systems Operation Techniques
background and structure of each model is discussed, and the functions used to represent the major processes involved are
described. The input/output requirements and the range of application of models are also discussed. Simulation models have
also been extensively used in combination with optimisation models. Karamouz and Houck (1982) describe an algorithm
that cycles through an optimisation model, a regression analysis and a simulation model to develop reservoir operating rules.
Labadie et al. (1987) presents an application of a simulation model in estimating the reliable power capacity of a reservoir
system.Recently, researchers have tried to incorporate optimisation methods within the simulation models. Wardlaw (1993)
has developed a simulation model which incorporates economic functions for hydropower, agriculture and fisheries
production. The model was used to assess the economics of alternative strategies for water resources development in the
Brantas Basin in Indonesia. Jain et al. (1998) describe the application of a simulation model to reservoir operation studies of
Sabarmati system in India. Operating procedures were derived for all the four reservoirs of the system.
III. RESERVOIR OPERATIONS UNDER CLIMATE CHANGE
Due to changes in spatial and temporal availability of water at reservoir sites, reservoir management is likely to be
influenced. Several studies have been conducted to evaluate hydrological impacts of climate change on watersheds in
different parts of the world. Applications of optimization techniques to derive reservoir operating rules have been described
by many researchers (e.g., Oliveira and Loucks 1997; Sharif and Wardlaw, 2000; Tu etal. 2003). Applications describing the
impacts of climate change on reservoir operations are, however, very few. Klemes (1985) performed an assessment of the
anticipated sensitivity of water resource systems to climatic variations, and found that (a) decrease in reliability might occur
much faster than any decrease in precipitation or increase in evaporation losses; (b) the impact of drier climate would be
more severe where the present level of development is high than where it is low; and (c) the relative effect of the
precipitation change would probably be greater than that of the evapo-transpiration change. Burn and Simonovic (1996)
investigated the potential impacts of changing climatic conditions on the operational performance of water resource systems.
Reservoir operation was carried out for two potential monthly flow sequences reflecting two different sets of climatic
conditions. Reliability (the probability of success) and resilience (a measure of how quickly the reservoir will recover from a
failure) criteria were used to show that, despite moderate changes in inflow characteristics, the values of the performance
criteria are substantially impacted. It was concluded that the reservoir performance was sensitive to the inflow data.More
recently, Minville et al. (2010) evaluated the impacts of climate change on medium-term reservoir operations for the
Peribonka water resource system. The results of simulations clearly indicated the tendency for reduction in mean annual
hydropower production and an increase in spills, despite an increase in the annual average inflow to the reservoirs. This
reduction was partly attributed to the impacts of climate change. Whitfield and Cannon (2000) analyzed recent (1976-1995)
climatic and hydrological variations in Canada and found that even small changes in precipitation and temperature
considerably affect river discharges. Christensen et al. (2004) claimed that statistically insignificant changes in the inflows
would have large impacts on reservoir storage. Consequently, reservoir operation procedures are likely to be impacted.
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