Pub Date : 2019-04-09DOI: 10.11121/IJOCTA.01.2019.00743
O. Mostafa, A. Souissi, M. Ziani
We propose a modification of limited memory Broyden methods, called dynamical Broyden rank reduction method, to solve high dimensional systems of nonlinear equations. Based on a thresholding process of singular values, the proposed method determines a priori the rank of the reduced update matrix. It significantly reduces the number of singular values decomposition calls of the update matrix during the iterations. Local superlinear convergence of the method is proved and some numerical examples are displayed.
{"title":"A New Broyden rank reduction method to solve large systems of nonlinear equations","authors":"O. Mostafa, A. Souissi, M. Ziani","doi":"10.11121/IJOCTA.01.2019.00743","DOIUrl":"https://doi.org/10.11121/IJOCTA.01.2019.00743","url":null,"abstract":"We propose a modification of limited memory Broyden methods, called dynamical Broyden rank reduction method, to solve high dimensional systems of nonlinear equations. Based on a thresholding process of singular values, the proposed method determines a priori the rank of the reduced update matrix. It significantly reduces the number of singular values decomposition calls of the update matrix during the iterations. Local superlinear convergence of the method is proved and some numerical examples are displayed.","PeriodicalId":37369,"journal":{"name":"International Journal of Optimization and Control: Theories and Applications","volume":"41 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2019-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74632132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-03-20DOI: 10.11121/IJOCTA.01.2019.00685
Sevcan Emek, Vedat Evren, Şebnem Bora
This study provides a detailed explanation of a regulating mechanism of the blood glucose levels by an agent-based software engineering tool. Repast Simphony which is used in implementation of this study is an agent-based software engineering tool based on the object-oriented programming using Java language. Agent-based modeling and simulation is a computational methodology for simulating and exploring phenomena that includes a large set of active components represented by agents. The agents are main components situated in space and time of agent-based simulation environment. In this study, we present hormonal regulation of blood glucose levels by our improved agent-based control mechanism. Hormonal regulation of blood glucose levels is an important process to maintain homeostasis inside the human body. We offer a negative feedback control mechanism with agent-based modeling approach to regulate the secretion of insulin hormone which is responsible for increasing the blood glucose levels. The negative feedback control mechanism run by three main agents that interact with each other to perform their local actions in the simulation environment. The result of this study shows the local behavior of the agents in the negative feedback loop and illustrates how to balance the blood glucose levels. Finally, this study which is thought a potential implementation of agent-based modeling and simulation may contribute to the exploration of other homeostatic control systems inside the human body.
{"title":"Simulation of glucose regulating mechanism with an agent-based software engineering tool","authors":"Sevcan Emek, Vedat Evren, Şebnem Bora","doi":"10.11121/IJOCTA.01.2019.00685","DOIUrl":"https://doi.org/10.11121/IJOCTA.01.2019.00685","url":null,"abstract":"This study provides a detailed explanation of a regulating mechanism of the blood glucose levels by an agent-based software engineering tool. Repast Simphony which is used in implementation of this study is an agent-based software engineering tool based on the object-oriented programming using Java language. Agent-based modeling and simulation is a computational methodology for simulating and exploring phenomena that includes a large set of active components represented by agents. The agents are main components situated in space and time of agent-based simulation environment. In this study, we present hormonal regulation of blood glucose levels by our improved agent-based control mechanism. Hormonal regulation of blood glucose levels is an important process to maintain homeostasis inside the human body. We offer a negative feedback control mechanism with agent-based modeling approach to regulate the secretion of insulin hormone which is responsible for increasing the blood glucose levels. The negative feedback control mechanism run by three main agents that interact with each other to perform their local actions in the simulation environment. The result of this study shows the local behavior of the agents in the negative feedback loop and illustrates how to balance the blood glucose levels. Finally, this study which is thought a potential implementation of agent-based modeling and simulation may contribute to the exploration of other homeostatic control systems inside the human body.","PeriodicalId":37369,"journal":{"name":"International Journal of Optimization and Control: Theories and Applications","volume":"21 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2019-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88949955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-03-19DOI: 10.11121/IJOCTA.01.2019.00602
Nurgül Okur, I. Işcan, Emine Yuksek Dizdar
In this study are investigated p-convex stochastic processes which are extensions of convex stochastic processes. A suitable example is also given for this process. In addition, in this case a p-convex stochastic process is increasing or decreasing, the relation with convexity is revealed. The concept of inequality as convexity has an important place in literature, since it provides a broader setting to study the optimization and mathematical programming problems. Therefore, Hermite-Hadamard type inequalities for p-convex stochastic processes and some boundaries for these inequalities are obtained in present study. It is used the concept of mean-square integrability for stochastic processes to obtain the above mentioned results.
{"title":"Hermite-Hadamard type inequalities for p-convex stochastic processes","authors":"Nurgül Okur, I. Işcan, Emine Yuksek Dizdar","doi":"10.11121/IJOCTA.01.2019.00602","DOIUrl":"https://doi.org/10.11121/IJOCTA.01.2019.00602","url":null,"abstract":"In this study are investigated p-convex stochastic processes which are extensions of convex stochastic processes. A suitable example is also given for this process. In addition, in this case a p-convex stochastic process is increasing or decreasing, the relation with convexity is revealed. The concept of inequality as convexity has an important place in literature, since it provides a broader setting to study the optimization and mathematical programming problems. Therefore, Hermite-Hadamard type inequalities for p-convex stochastic processes and some boundaries for these inequalities are obtained in present study. It is used the concept of mean-square integrability for stochastic processes to obtain the above mentioned results.","PeriodicalId":37369,"journal":{"name":"International Journal of Optimization and Control: Theories and Applications","volume":"1 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2019-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85199392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-03-19DOI: 10.11121/IJOCTA.01.2019.00780
H. Yildirim, M. Yavuz
Countries aiming for sustainability in economic growth and development ensure the reliability of energy supplies. For countries to provide their energy needs uninterruptedly, it is important for domestic and renewable energy sources to be utilised. For this reason, the supply of reliable and sustainable energy has become an important issue that concerns and occupies mankind. Of the renewable energy sources, wind energy is a clean, reliable and inexhaustible source of energy with low operating costs. Turkey is a rich nation in terms of wind energy potential. Forecasting of investment efficiency is an important issue before and during the investment period in wind energy investment process because of high investment costs. It is aimed to forecast the wind energy products monthly with multilayer neural network approach in this study. For this aim a feed forward back propagation neural network model has been established. As a set of data, wind speed values 48 months (January 2012-December 2015) have been used. The training data set occurs from 36 monthly wind speed values (January 2012-December 2014) and the test data set occurs from other values (January-December 2015). Analysis findings show that the trained Artificial Neural Networks (ANNs) have the ability of accurate prediction for the samples that are not used at training phase. The prediction errors for the wind energy plantation values are ranged between 0.00494-0.015035. Also the overall mean prediction error for this prediction is calculated as 0.004818 (0.48%). In general, we can say that ANNs be able to estimate the aspect of wind energy plant productions.
{"title":"Evaluation of wind energy investment with artificial neural networks","authors":"H. Yildirim, M. Yavuz","doi":"10.11121/IJOCTA.01.2019.00780","DOIUrl":"https://doi.org/10.11121/IJOCTA.01.2019.00780","url":null,"abstract":"Countries aiming for sustainability in economic growth and development ensure the reliability of energy supplies. For countries to provide their energy needs uninterruptedly, it is important for domestic and renewable energy sources to be utilised. For this reason, the supply of reliable and sustainable energy has become an important issue that concerns and occupies mankind. Of the renewable energy sources, wind energy is a clean, reliable and inexhaustible source of energy with low operating costs. Turkey is a rich nation in terms of wind energy potential. Forecasting of investment efficiency is an important issue before and during the investment period in wind energy investment process because of high investment costs. It is aimed to forecast the wind energy products monthly with multilayer neural network approach in this study. For this aim a feed forward back propagation neural network model has been established. As a set of data, wind speed values 48 months (January 2012-December 2015) have been used. The training data set occurs from 36 monthly wind speed values (January 2012-December 2014) and the test data set occurs from other values (January-December 2015). Analysis findings show that the trained Artificial Neural Networks (ANNs) have the ability of accurate prediction for the samples that are not used at training phase. The prediction errors for the wind energy plantation values are ranged between 0.00494-0.015035. Also the overall mean prediction error for this prediction is calculated as 0.004818 (0.48%). In general, we can say that ANNs be able to estimate the aspect of wind energy plant productions.","PeriodicalId":37369,"journal":{"name":"International Journal of Optimization and Control: Theories and Applications","volume":"20 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2019-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88846577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-03-19DOI: 10.11121/IJOCTA.01.2019.00762
H. Yildirim, Sakir Sakarya
Energy has become one of the most important building blocks of many changes in the world, and it still maintains this quality. The demand for natural resources and energy continues to increase daily. For this reason, the supply of reliable and sustainable energy has become an important issue that concerns and occupies mankind. Of the renewable energy sources, wind energy is a clean, reliable and inexhaustible source of energy with low operating costs. Turkey is a rich nation in terms of wind energy potential. In this context, the profitability of investments made in utilising domestic and renewable energy potential is important. Investment efficiency is a very important issue before and during the investment period due to the fact that wind energy investments are high cost investments. In this study, a solution will be proposed for the replacement of inefficient wind turbines which have been installed. In the ideal solution of the issue, the remaining lifetime of the wind turbine which is to be replaced and capacity utilization at the new location of the turbine will be used as key input factors. The results showed that it was important for the relocation decision to be made early for the investment to be more profitable. In the event of delayed decisions to relocate the turbine, a high capacity factor is expected in the new location. If a high capacity factor is not achieved, the relocation of the turbine will be meaningless and losses will be incurred for the investor. Also according to the results of the analysis, in the first two years, the turbine operating at a low capacity of 19% and 17% is profitable if it works at 26% capacity until the end of its economic life when change is made in the third year.
{"title":"Investment evaluation of wind turbine relocation","authors":"H. Yildirim, Sakir Sakarya","doi":"10.11121/IJOCTA.01.2019.00762","DOIUrl":"https://doi.org/10.11121/IJOCTA.01.2019.00762","url":null,"abstract":"Energy has become one of the most important building blocks of many changes in the world, and it still maintains this quality. The demand for natural resources and energy continues to increase daily. For this reason, the supply of reliable and sustainable energy has become an important issue that concerns and occupies mankind. Of the renewable energy sources, wind energy is a clean, reliable and inexhaustible source of energy with low operating costs. Turkey is a rich nation in terms of wind energy potential. In this context, the profitability of investments made in utilising domestic and renewable energy potential is important. Investment efficiency is a very important issue before and during the investment period due to the fact that wind energy investments are high cost investments. In this study, a solution will be proposed for the replacement of inefficient wind turbines which have been installed. In the ideal solution of the issue, the remaining lifetime of the wind turbine which is to be replaced and capacity utilization at the new location of the turbine will be used as key input factors. The results showed that it was important for the relocation decision to be made early for the investment to be more profitable. In the event of delayed decisions to relocate the turbine, a high capacity factor is expected in the new location. If a high capacity factor is not achieved, the relocation of the turbine will be meaningless and losses will be incurred for the investor. Also according to the results of the analysis, in the first two years, the turbine operating at a low capacity of 19% and 17% is profitable if it works at 26% capacity until the end of its economic life when change is made in the third year.","PeriodicalId":37369,"journal":{"name":"International Journal of Optimization and Control: Theories and Applications","volume":"55 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2019-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84768582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-03-13DOI: 10.11121/IJOCTA.01.2019.00628
Süleyman Öğrekçi
In this paper, we consider the stability problem of delay differential equations in the sense of Hyers-Ulam-Rassias. Recently this problem has been solved for bounded intervals, our result extends and improve the literature by obtaining stability in unbounded intervals. An illustrative example is also given to compare these results and visualize the improvement.
{"title":"Stability of delay differential equations in the sense of Ulam on unbounded intervals","authors":"Süleyman Öğrekçi","doi":"10.11121/IJOCTA.01.2019.00628","DOIUrl":"https://doi.org/10.11121/IJOCTA.01.2019.00628","url":null,"abstract":"In this paper, we consider the stability problem of delay differential equations in the sense of Hyers-Ulam-Rassias. Recently this problem has been solved for bounded intervals, our result extends and improve the literature by obtaining stability in unbounded intervals. An illustrative example is also given to compare these results and visualize the improvement.","PeriodicalId":37369,"journal":{"name":"International Journal of Optimization and Control: Theories and Applications","volume":"23 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2019-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90539251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-02-19DOI: 10.11121/ijocta.01.2019.00655
Sukran Seker
Risk analysis is a systematic and widespread methodology to analyze and evaluate risks which are exposed in many working areas. One of the Quantitative Risk Analysis (QRA) methods for risk assessment is Bow-Tie analysis which combines features of fault-tree analysis and event-tree analysis to identify the top event; its causes and consequences (outcomes); and possible preventive and protective control measures or barriers. This study proposes an occupational risk assessment approach, which is known as Fuzzy Bow-Tie analysis, for pharmaceutical industry processes and work units. The aim is to evaluate critical risks and risky pharmaceutical work units and take safety precautions against accidents which caused by risky conditions. Thus, this methodology combines the concept of uncertainty which comes from different (Decision Maker) DM’s evaluations and the whole performance of the Bow-Tie analysis for hazard identification and risk assessment. To apply and validate the proposed method, a case study is performed for pharmaceutical industry processes and work units. Based on the computed risk score, which is calculated by multiplying probability ranking and impact ranking of criterion, the risks are prioritized and some measures are suggested for management to prevent accidents occur in the industry.
{"title":"Analyzing occupational risks of pharmaceutical industry under uncertainty using a Bow-Tie analysis","authors":"Sukran Seker","doi":"10.11121/ijocta.01.2019.00655","DOIUrl":"https://doi.org/10.11121/ijocta.01.2019.00655","url":null,"abstract":"Risk analysis is a systematic and widespread methodology to analyze and evaluate risks which are exposed in many working areas. One of the Quantitative Risk Analysis (QRA) methods for risk assessment is Bow-Tie analysis which combines features of fault-tree analysis and event-tree analysis to identify the top event; its causes and consequences (outcomes); and possible preventive and protective control measures or barriers. This study proposes an occupational risk assessment approach, which is known as Fuzzy Bow-Tie analysis, for pharmaceutical industry processes and work units. The aim is to evaluate critical risks and risky pharmaceutical work units and take safety precautions against accidents which caused by risky conditions. Thus, this methodology combines the concept of uncertainty which comes from different (Decision Maker) DM’s evaluations and the whole performance of the Bow-Tie analysis for hazard identification and risk assessment. To apply and validate the proposed method, a case study is performed for pharmaceutical industry processes and work units. Based on the computed risk score, which is calculated by multiplying probability ranking and impact ranking of criterion, the risks are prioritized and some measures are suggested for management to prevent accidents occur in the industry.","PeriodicalId":37369,"journal":{"name":"International Journal of Optimization and Control: Theories and Applications","volume":"250 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2019-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76986066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-02-15DOI: 10.11121/IJOCTA.01.2019.00642
G. Ertas
Intravoxel incoherent motion (IVIM) modeling offers the parameters f, D and D* as biomarkers for different lesion types and cancer stages from diffusion MR signals. Challenges with the available optimization algorithms in fitting the model to the signals motive new studies for improved parameter estimations. In this study, one thousand value sets of f, D, D* for human breast are assembled and used to generate five thousand diffusion MR signals considering noise-free and noisy situations exhibiting signal-to-noise ratios (SNR) of 20, 40, 60 and 80. The estimates of f, D, D* are obtained using Levenberg-Marquardt (LM), trust-region (TR) and particle swarm (PS) algorithms. On average, the algorithms provide the highest fitting performance for the noise-free signals (R2adj=1.000) and great fitting performances on the noisy signals with SNR>20 (R2adj>0.988). TR algorithm performs slightly better for SNR=20 (R2adj=0.947). TR and PS algorithms achieve the highest parameter estimation performance for all the parameters while LM algorithm reveals the highest performance for f and D only on the noise-free signals (r=1.00). For the noisy signals, performances increase while SNR increases. All algorithms accomplish poor performances for D* (r=0.01-0.20) while TR and PS algorithms perform same for f (r=0.48-0.97) and D (r=0.85-0.99) but remarkably better than LM algorithm for f (r=0.08-0.97) and D (r=0.53-0.99). Overall, TR and PS algorithms demonstrate better but indistinguishable performances. Without requiring any user-given initial value, PS algorithm may facilitate improved estimation of IVIM parameters of the human breast tissue. Further studies are needed to determine its benefit in clinical practice.
{"title":"Fitting Intravoxel Incoherent Motion Model to Diffusion MR Signals of the Human Breast Tissue using Particle Swarm Optimization","authors":"G. Ertas","doi":"10.11121/IJOCTA.01.2019.00642","DOIUrl":"https://doi.org/10.11121/IJOCTA.01.2019.00642","url":null,"abstract":"Intravoxel incoherent motion (IVIM) modeling offers the parameters f, D and D* as biomarkers for different lesion types and cancer stages from diffusion MR signals. Challenges with the available optimization algorithms in fitting the model to the signals motive new studies for improved parameter estimations. In this study, one thousand value sets of f, D, D* for human breast are assembled and used to generate five thousand diffusion MR signals considering noise-free and noisy situations exhibiting signal-to-noise ratios (SNR) of 20, 40, 60 and 80. The estimates of f, D, D* are obtained using Levenberg-Marquardt (LM), trust-region (TR) and particle swarm (PS) algorithms. On average, the algorithms provide the highest fitting performance for the noise-free signals (R2adj=1.000) and great fitting performances on the noisy signals with SNR>20 (R2adj>0.988). TR algorithm performs slightly better for SNR=20 (R2adj=0.947). TR and PS algorithms achieve the highest parameter estimation performance for all the parameters while LM algorithm reveals the highest performance for f and D only on the noise-free signals (r=1.00). For the noisy signals, performances increase while SNR increases. All algorithms accomplish poor performances for D* (r=0.01-0.20) while TR and PS algorithms perform same for f (r=0.48-0.97) and D (r=0.85-0.99) but remarkably better than LM algorithm for f (r=0.08-0.97) and D (r=0.53-0.99). Overall, TR and PS algorithms demonstrate better but indistinguishable performances. Without requiring any user-given initial value, PS algorithm may facilitate improved estimation of IVIM parameters of the human breast tissue. Further studies are needed to determine its benefit in clinical practice.","PeriodicalId":37369,"journal":{"name":"International Journal of Optimization and Control: Theories and Applications","volume":"16 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2019-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88770480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-02-14DOI: 10.11121/IJOCTA.01.2019.00597
Zehra Pinar
In this study, we introduce the lossy nonlinear transmission line equation, which is the dissipative-dispersive equation and an important problem of electrical transmission lines. For the engineers and physicist, the equation and its exact solutions are important so to obtain the exact solutions; one of the modifications of auxiliary equation method based on Chebyshev differential equation is studied. The results are discussed and given in details. Recently, the studies of lossy transmission line equation have been challenging, thus, it is believed that the proposed solutions will be key part of further studies for waves in nonlinear transmission line media, which has mixed dissipative-dispersive behavior.
{"title":"Analytical studies on waves in nonlinear transmission line media","authors":"Zehra Pinar","doi":"10.11121/IJOCTA.01.2019.00597","DOIUrl":"https://doi.org/10.11121/IJOCTA.01.2019.00597","url":null,"abstract":"In this study, we introduce the lossy nonlinear transmission line equation, which is the dissipative-dispersive equation and an important problem of electrical transmission lines. For the engineers and physicist, the equation and its exact solutions are important so to obtain the exact solutions; one of the modifications of auxiliary equation method based on Chebyshev differential equation is studied. The results are discussed and given in details. Recently, the studies of lossy transmission line equation have been challenging, thus, it is believed that the proposed solutions will be key part of further studies for waves in nonlinear transmission line media, which has mixed dissipative-dispersive behavior.","PeriodicalId":37369,"journal":{"name":"International Journal of Optimization and Control: Theories and Applications","volume":"87 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2019-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90942173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-02-06DOI: 10.11121/IJOCTA.01.2019.00718
E. N. Kapukaya, A. Bal, S. I. Satoglu
The Triple-bottom-line concept suggests that firms must consider the environmental and social impacts of their decisions, beside the economic aspects. Hence, the sustainability of the firms’ operations can be reached. The purpose of this study is to develop a bi-objective, multi-product and multi-period mixed-integer model for the operations planning of electrical-electronic waste (WEEE) recovery facilities, by considering social (workforce) constraints. Main objective is the minimization of net recycling and logistics costs offset by the profit earned by recovered material sales, and second objective is the maximization of hazardous materials recovery. Collection of used products from the specified regions is decided and the required machine-hours, inventory and workforce decisions are made. Besides, both weight-based and unit-based WEEE recovery targets are separately considered, as a unique aspect. A sensitivity analysis is conducted with various scrap prices to understand operations planning in changing conditions. Results show that weight-based targets enhance recovery amounts.
{"title":"A bi-objective model for sustainable logistics and operations planning of WEEE recovery","authors":"E. N. Kapukaya, A. Bal, S. I. Satoglu","doi":"10.11121/IJOCTA.01.2019.00718","DOIUrl":"https://doi.org/10.11121/IJOCTA.01.2019.00718","url":null,"abstract":"The Triple-bottom-line concept suggests that firms must consider the environmental and social impacts of their decisions, beside the economic aspects. Hence, the sustainability of the firms’ operations can be reached. The purpose of this study is to develop a bi-objective, multi-product and multi-period mixed-integer model for the operations planning of electrical-electronic waste (WEEE) recovery facilities, by considering social (workforce) constraints. Main objective is the minimization of net recycling and logistics costs offset by the profit earned by recovered material sales, and second objective is the maximization of hazardous materials recovery. Collection of used products from the specified regions is decided and the required machine-hours, inventory and workforce decisions are made. Besides, both weight-based and unit-based WEEE recovery targets are separately considered, as a unique aspect. A sensitivity analysis is conducted with various scrap prices to understand operations planning in changing conditions. Results show that weight-based targets enhance recovery amounts.","PeriodicalId":37369,"journal":{"name":"International Journal of Optimization and Control: Theories and Applications","volume":"55 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2019-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86152551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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