I am a graduate of Bogazici University. I have been employed by various universities in Istabul, Izmir and Singapore. My interests lie in disaster relief, evacuation, injured tranportation, global optimization, heuristics and supply chains.
In the aftermath of a major earthquake, delivery of essential services to survivors is of utmost ... more In the aftermath of a major earthquake, delivery of essential services to survivors is of utmost importance and in urban areas it is conducted using road networks that are already stressed by road damages, other urban traffic and evacuation. Relief distribution efforts should be planned carefully in order to create minimal additional traffic congestion. We propose a dynamic relief distribution model where relief trucks share limited capacity road networks with counterflows resulting from car traffic. We develop a MIP model for this problem and solve it by decomposing the road network geographically and solving each subnetwork iteratively using the Relax and Fix method. 1. Introduction. Traffic congestion occurs in the aftermath of earthquakes and other disasters due to demolition debris, relief distribution, evacuation traffic and other urban traffic. The problem of post-disaster relief distribution over limited capacity road networks has not received much attention in the Disaster Operations Management (DOM) literature [13, 18, 4, 33, 23]. To our knowledge, the only citation that mentions post-earthquake traffic management is that of Feng and Wen [21] who emphasize traffic control given certain origin-destination (o-d) relief trips. However, in this article the vehicle routing problem is not explicitly considered, rather a path selection model for satisfying traffic flow between o-d pairs and other incoming traffic is presented. In this study, we consider optimizing the routes of relief trucks that provide service to handicapped, old, sickly or otherwise affected people who cannot walk or drive to the nearest aid distribution center. Each street has a given number of needy people determined by census data. Once a truck arrives, these people fetch their goods within a few minutes and return to their homes. The truck then moves on to the next street on its tour. A truck is also allowed to transit a street without stopping. In our model, a set of relief trucks enters a neighborhood and visits a number of streets, i.e., links in a road network, during a given time span (maximum tour length) while sharing the road capacity with car traffic flows. We assume that relief distribution to needy persons is repeated daily until consumer supply chains
This article describes a new fuzzy areal site assessment approach in the detection of contaminate... more This article describes a new fuzzy areal site assessment approach in the detection of contaminated zones within a site which is under environmental investigation. Conventional techniques utilized in this field are mostly interpolation based. These methods interpolate the contaminant concentration values at unobserved locations using observed values. Unlike these interpolation techniques, the motivation of the approach introduced here consists of
ABSTRACT This paper deals with an important problem in the last phase of manufacturing in the tex... more ABSTRACT This paper deals with an important problem in the last phase of manufacturing in the textile industry. This involves cutting large lengths of fabric into smaller pieces, which are then wrapped around rolls. The quality of cloth rolls transported to the customer is specified by the quality of fabric pieces that make up the roll. A piece of fabric falls within a given quality category if some of its characteristics, such as, piece length, the number of critical defects per metre, and the defective score per metre, are compatible with the corresponding quality specifications. Naturally, the selling price per metre of fabric is proportional to the quality category. Thus, it becomes necessary to determine an optimal cutting strategy of very long woven fabric (e.g. 2000 m) into smaller pieces (e.g. each 130 m long at most), which involves a difficult continuous assignment problem of identifying the optimal cutting locations of pieces overlapping with defects of known lengths and locations. Not only must the scrap be minimized but the overall profit per metre fabric should be maximized. The two objectives may not always support each other due to relative unit selling prices of various quality categories. The solution to this problem has an immediate impact on company profit. The mathematical formulation of the problem involves numerous binary variables as well as continuous variables. A Mutative Simulated Annealing approach is proposed here to solve this problem. The solution technique is tested both on real data obtained from a textile manufacturer and hypothetical data. Results are compared against upper bounds calculated for each objective defined, as well as with a sequential heuristic designed for this problem.
ABSTRACT In this study, a global optimization meta-heuristic is developed for the problem of dete... more ABSTRACT In this study, a global optimization meta-heuristic is developed for the problem of determining the optimum data distribution and degree of parallelism in parallelizing a sequential program for distributed memory machines. The parallel program is considered as the union of consecutive stages and the method deals with all the stages in the entire program rather than proposing solutions for each stage. The meta-heuristic developed here for this specific problem combines simulated annealing and hill climbing (SA-HC) in the search for the optimum configuration. Performance is tested in terms of the total execution time of the program including communication and computation times. Two exemplary codes from the literature, the first being computation intensive and the second being communication intensive, are utilized in the experiments. The performance of the SA-HC algorithm provides satisfactory results for these illustrative examples.
International Journal of Production Research, 1998
... The loading problem considered here can be de®ned as a bin packing problem with bins of multi... more ... The loading problem considered here can be de®ned as a bin packing problem with bins of multiple classes. ... The method initially sets all families to their lower bounds and gradually increases lot sizes in prede®ned increments, one family at each step. ...
Commercial projects are undertaken with the expectation of maximizing financial returns. There ar... more Commercial projects are undertaken with the expectation of maximizing financial returns. There are a variety of cash flow models in the literature in which payments, whose amounts depend on the type of contract quoted between the contractor and the client, are tied to the project events or to the completion times of activities. These models are of deterministic nature with
IEEE Transactions on Systems, Man and Cybernetics, Part C (Applications and Reviews), 1999
... Here we propose a genetic algorithm (GA) approach to deal with this problem. ... The major ge... more ... Here we propose a genetic algorithm (GA) approach to deal with this problem. ... The major genetic operators that re-flect nature's evolutionary process are reproduction, crossover, and mutation ... The GA approach proposed here is denoted as hybrid GA (HGA), and it integrates the ...
Abstract. Global optimization involves the difficult task of the identification of global extremi... more Abstract. Global optimization involves the difficult task of the identification of global extremities of mathematical functions. Such problems are often encountered in practice in various fields, eg, molecular biology, physics, industrial chemistry. In this work, we develop five different ...
The Site Characterization Approach for Recovery of contaminated industrial sites (SCAR) is being ... more The Site Characterization Approach for Recovery of contaminated industrial sites (SCAR) is being developed to enable the results of the Project “Protection of groundwater resources at industrially contaminated sites (PURE project)” to be integrated and efficiently used by site owners to take the relevant decisions for site management. SCAR has been tested and detailed in the last year of the PURE project. The project results show what input, activity and criteria are needed to obtain an output that meets the expectations of both the developers and end-users of the project as much as possible. The approach is divided in three main phases. Phase 1 gives a first fast, relatively cheap, impression of the risks, benefits and cost of the remediation of the contamination involved. Phase 2 gives the risks (technical, economical, HSE, political), benefits and costs more detailed. In phase 3 field test are carried out at the site and the site is actually remediated. It is the goal of the PURE...
PURE is aimed at preventing contamination of groundwater from industrial sites from priority poll... more PURE is aimed at preventing contamination of groundwater from industrial sites from priority pollutants, including recalcitrant chloroorganics, BTEX and PAH compounds and heavy metals. The overall structure of the project is summarised in Figure 1. Sub-project SICHAMORE is designed to generate data and give added value to site owners to allow a decision to be reached regarding the remediation of a contaminated site. The integration of these work packages forms the basis of SCAR: Site Characterisation Approach for Recovery of contaminated industrial sites. SCAR is designed to: • give an overview of the different steps of site characterisation that could be applied on different sites and could be adapted to the needs of the site owner; • contribute to the formulation of a comprehensive and structured overview for the sites in the PURE project; • provide an inventory of existing and historical site development; • indicate possible site remediation scenarios with associated technical an...
International Journal of Operations & …, Jan 1, 1995
Proposes a heuristic iterative scheduling algorithm for the resource constrained project scheduli... more Proposes a heuristic iterative scheduling algorithm for the resource constrained project scheduling problem. Considers a general model where activities are represented by multiple operating modes and each operating mode is constituted of different activity durations and resource ...
In the aftermath of a major earthquake, delivery of essential services to survivors is of utmost ... more In the aftermath of a major earthquake, delivery of essential services to survivors is of utmost importance and in urban areas it is conducted using road networks that are already stressed by road damages, other urban traffic and evacuation. Relief distribution efforts should be planned carefully in order to create minimal additional traffic congestion. We propose a dynamic relief distribution model where relief trucks share limited capacity road networks with counterflows resulting from car traffic. We develop a MIP model for this problem and solve it by decomposing the road network geographically and solving each subnetwork iteratively using the Relax and Fix method. 1. Introduction. Traffic congestion occurs in the aftermath of earthquakes and other disasters due to demolition debris, relief distribution, evacuation traffic and other urban traffic. The problem of post-disaster relief distribution over limited capacity road networks has not received much attention in the Disaster Operations Management (DOM) literature [13, 18, 4, 33, 23]. To our knowledge, the only citation that mentions post-earthquake traffic management is that of Feng and Wen [21] who emphasize traffic control given certain origin-destination (o-d) relief trips. However, in this article the vehicle routing problem is not explicitly considered, rather a path selection model for satisfying traffic flow between o-d pairs and other incoming traffic is presented. In this study, we consider optimizing the routes of relief trucks that provide service to handicapped, old, sickly or otherwise affected people who cannot walk or drive to the nearest aid distribution center. Each street has a given number of needy people determined by census data. Once a truck arrives, these people fetch their goods within a few minutes and return to their homes. The truck then moves on to the next street on its tour. A truck is also allowed to transit a street without stopping. In our model, a set of relief trucks enters a neighborhood and visits a number of streets, i.e., links in a road network, during a given time span (maximum tour length) while sharing the road capacity with car traffic flows. We assume that relief distribution to needy persons is repeated daily until consumer supply chains
This article describes a new fuzzy areal site assessment approach in the detection of contaminate... more This article describes a new fuzzy areal site assessment approach in the detection of contaminated zones within a site which is under environmental investigation. Conventional techniques utilized in this field are mostly interpolation based. These methods interpolate the contaminant concentration values at unobserved locations using observed values. Unlike these interpolation techniques, the motivation of the approach introduced here consists of
ABSTRACT This paper deals with an important problem in the last phase of manufacturing in the tex... more ABSTRACT This paper deals with an important problem in the last phase of manufacturing in the textile industry. This involves cutting large lengths of fabric into smaller pieces, which are then wrapped around rolls. The quality of cloth rolls transported to the customer is specified by the quality of fabric pieces that make up the roll. A piece of fabric falls within a given quality category if some of its characteristics, such as, piece length, the number of critical defects per metre, and the defective score per metre, are compatible with the corresponding quality specifications. Naturally, the selling price per metre of fabric is proportional to the quality category. Thus, it becomes necessary to determine an optimal cutting strategy of very long woven fabric (e.g. 2000 m) into smaller pieces (e.g. each 130 m long at most), which involves a difficult continuous assignment problem of identifying the optimal cutting locations of pieces overlapping with defects of known lengths and locations. Not only must the scrap be minimized but the overall profit per metre fabric should be maximized. The two objectives may not always support each other due to relative unit selling prices of various quality categories. The solution to this problem has an immediate impact on company profit. The mathematical formulation of the problem involves numerous binary variables as well as continuous variables. A Mutative Simulated Annealing approach is proposed here to solve this problem. The solution technique is tested both on real data obtained from a textile manufacturer and hypothetical data. Results are compared against upper bounds calculated for each objective defined, as well as with a sequential heuristic designed for this problem.
ABSTRACT In this study, a global optimization meta-heuristic is developed for the problem of dete... more ABSTRACT In this study, a global optimization meta-heuristic is developed for the problem of determining the optimum data distribution and degree of parallelism in parallelizing a sequential program for distributed memory machines. The parallel program is considered as the union of consecutive stages and the method deals with all the stages in the entire program rather than proposing solutions for each stage. The meta-heuristic developed here for this specific problem combines simulated annealing and hill climbing (SA-HC) in the search for the optimum configuration. Performance is tested in terms of the total execution time of the program including communication and computation times. Two exemplary codes from the literature, the first being computation intensive and the second being communication intensive, are utilized in the experiments. The performance of the SA-HC algorithm provides satisfactory results for these illustrative examples.
International Journal of Production Research, 1998
... The loading problem considered here can be de®ned as a bin packing problem with bins of multi... more ... The loading problem considered here can be de®ned as a bin packing problem with bins of multiple classes. ... The method initially sets all families to their lower bounds and gradually increases lot sizes in prede®ned increments, one family at each step. ...
Commercial projects are undertaken with the expectation of maximizing financial returns. There ar... more Commercial projects are undertaken with the expectation of maximizing financial returns. There are a variety of cash flow models in the literature in which payments, whose amounts depend on the type of contract quoted between the contractor and the client, are tied to the project events or to the completion times of activities. These models are of deterministic nature with
IEEE Transactions on Systems, Man and Cybernetics, Part C (Applications and Reviews), 1999
... Here we propose a genetic algorithm (GA) approach to deal with this problem. ... The major ge... more ... Here we propose a genetic algorithm (GA) approach to deal with this problem. ... The major genetic operators that re-flect nature's evolutionary process are reproduction, crossover, and mutation ... The GA approach proposed here is denoted as hybrid GA (HGA), and it integrates the ...
Abstract. Global optimization involves the difficult task of the identification of global extremi... more Abstract. Global optimization involves the difficult task of the identification of global extremities of mathematical functions. Such problems are often encountered in practice in various fields, eg, molecular biology, physics, industrial chemistry. In this work, we develop five different ...
The Site Characterization Approach for Recovery of contaminated industrial sites (SCAR) is being ... more The Site Characterization Approach for Recovery of contaminated industrial sites (SCAR) is being developed to enable the results of the Project “Protection of groundwater resources at industrially contaminated sites (PURE project)” to be integrated and efficiently used by site owners to take the relevant decisions for site management. SCAR has been tested and detailed in the last year of the PURE project. The project results show what input, activity and criteria are needed to obtain an output that meets the expectations of both the developers and end-users of the project as much as possible. The approach is divided in three main phases. Phase 1 gives a first fast, relatively cheap, impression of the risks, benefits and cost of the remediation of the contamination involved. Phase 2 gives the risks (technical, economical, HSE, political), benefits and costs more detailed. In phase 3 field test are carried out at the site and the site is actually remediated. It is the goal of the PURE...
PURE is aimed at preventing contamination of groundwater from industrial sites from priority poll... more PURE is aimed at preventing contamination of groundwater from industrial sites from priority pollutants, including recalcitrant chloroorganics, BTEX and PAH compounds and heavy metals. The overall structure of the project is summarised in Figure 1. Sub-project SICHAMORE is designed to generate data and give added value to site owners to allow a decision to be reached regarding the remediation of a contaminated site. The integration of these work packages forms the basis of SCAR: Site Characterisation Approach for Recovery of contaminated industrial sites. SCAR is designed to: • give an overview of the different steps of site characterisation that could be applied on different sites and could be adapted to the needs of the site owner; • contribute to the formulation of a comprehensive and structured overview for the sites in the PURE project; • provide an inventory of existing and historical site development; • indicate possible site remediation scenarios with associated technical an...
International Journal of Operations & …, Jan 1, 1995
Proposes a heuristic iterative scheduling algorithm for the resource constrained project scheduli... more Proposes a heuristic iterative scheduling algorithm for the resource constrained project scheduling problem. Considers a general model where activities are represented by multiple operating modes and each operating mode is constituted of different activity durations and resource ...
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