Yazar "Alakas, Haci Mehmet" seçeneğine göre listele
Listeleniyor 1 - 18 / 18
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Assembly line balancing type-1 problem with assignment restrictions: A constraint programming modeling approach(Pamukkale Univ, 2021) Pınarbaşı, Mehmet; Alakas, Haci MehmetThe assembly line balancing problem (ALBP) contains some constraints which are cycle time/number of stations and precedence relations between tasks. However, due to the technological and organizational limitations, several other restrictions, such as linked tasks, incompatible tasks, station, and resource constraints, can be encountered in real production systems. In this study, we evaluate the effect of these restrictions on ALBP. For this purpose, a Constraint Programming (CP) model is proposed. The objective of the model is to minimize the number of stations for given cycle time (Type-1 problem). We investigate the solution quality of the proposed CP model according to the mixed-integer programming (MIP) and ABSALOM in terms of the several performance measurements such as the number of proofing optimal solution, number of the optimal solution, number of the best solution, relative gap between the solution with the optimal solution and average total solution time. Furthermore, the proposed approach is tested on the literature test instances, and the comparison results between models are reported. Although assignment restrictions increase the complexity of the problem, numerical experiments demonstrate that CP is an effective and high-quality solution method in solving ALBP.Öğe Balancing stochastic type-II assembly lines: chance-constrained mixed integer and constraint programming models(TAYLOR & FRANCIS LTD, 2020) Pinarbasi, Mehmet; Alakas, Haci MehmetIn the literature, line balancing is mostly investigated in deterministic environments. But production systems inevitably contain stochastic situations. In this study, the stochastic type-II assembly line balancing problem (ALBP) is considered. Firstly, a chance-constrained nonlinear mixed integer programming (MIP) formulation is developed from the well-known deterministic form. Then, a new linearized stochastic model is proposed by using some transformation approaches to reduce model complexity, and the model is solved. Finally, constraint programming (CP) models for deterministic ALBPs, nonlinear chance-constrained stochastic ALBPs and linearized chance-constrained stochastic ALBPs are developed, respectively. Problems from the literature are utilized to test the effectiveness of the proposed models and the results are compared with a bidirectional heuristic algorithm. The numerical results show that the CP models are more effective and successful for solving the stochastic ALBP. Some managerial implications are also suggested for industrial environments that consistently face ALBPs.Öğe Collection of recyclable wastes within the scope of the Zero Waste project: heterogeneous multi-vehicle routing case in Kirikkale(SPRINGER, 2020) Kiziltas, Safak; Alakas, Haci Mehmet; Eren, TamerThere is an increase in the amount of resource use due to the rise in population, urbanization, and industrialization. Also, the amount of waste increases due to an increase in consumption and resource use. Countries are developing new policies depending on both decreasing resources and environmental problems caused by waste. The "Zero Waste" project was launched to recycle waste and to reduce environmental pollution in Turkey. The project aims to separate recyclable waste at its source and recycle them. One of the problems encountered in the implementation of the project is collecting the waste from temporary storage areas. In this study, the problem of transportation of wastes from temporary warehouses to the main warehouse was discussed in Kirikkale/Turkey. A three-step solution approach has been proposed to the solution of the problem. In the first stage, the amounts of waste generated at the addresses to collect were estimated. In the second stage, the addresses to be visited are classified with an approach based on Pareto analysis according to the calculated waste amounts. According to this classification, it is planned which addresses will be visited on which day of the week. At the last stage, the problem is modeled as a heterogeneous multi-vehicle routing problem, which also takes into account the daily working hours and vehicle capacity constraints. According to the result of the mathematical model, the number of vehicles needed for waste collection, the types of vehicles, and the routes of the vehicles were found. Considering the implementation stages of the Zero Waste project, three different case studies are handled for Kirikkale. These case studies have been solved by considering different waste rates. According to the results, the waste collection plan was made economically by visiting fewer spots in a week.Öğe A constraint programming approach to type-2 assembly line balancing problem with assignment restrictions(Emerald Group Publishing Ltd, 2019) Pinarbasi, Mehmet; Alakas, Haci Mehmet; Yuzukirmizi, MustafaPurpose Main constraints for an assembly line balancing problem (ALBP) are cycle time/number of stations and task precedence relations. However, due to the technological and organizational limitations, several other restrictions can be encountered in real production systems. These restrictions are called as assignment restrictions and can be task assignment, station, resource and distance limitations. The purpose of the study is to evaluate the effects of these restrictions on ALBP using constraint programming (CP) model. Design/methodology/approach A novel CP model is proposed and compared to mixed-integer programming (MIP) as a benchmark. The objective is to minimize the cycle time for a given number of stations. The authors also provide explicit anthology of the assignment restriction effects on line efficiency, the solution quality and the computation time. Findings The proposed approach is verified with the literature test instances and a real-life problem from a furniture manufacturing company. Computational experiments show that, despite the fact that additional assignment restrictions are problematic in mathematical solutions, CP is a versatile exact solution alternative in modelling and the solution quality. Practical implications - Assembly line is a popular manufacturing system in the making of standardized high volume products. The problem of assembly line balancing is a crucial challenge in these settings and consists of assigning tasks to the stations by optimizing one or more objectives. Type-2 AR-ALBP is a specific case with the objective function of minimizing the cycle time for a given number of stations. It further assumes assignment restrictions that can be confronted due to the technological limitations or the strategic decisions of the company management. This is especially encountered in rebalancing lines. Originality/value Several solution approaches such as mathematical modelling, heuristic and meta-heuristic are proposed to solve the ALBP in the literature. In this study, a new approach has been presented using CP. Efficient models are developed for Type-2 ALBP with several assignment restrictions. Previous studies have not considered the problem to the presented extent. Furthermore, to the best of the authors' knowledge, the paper is the first study that solves ALBP with assignment restrictions using CP.Öğe Constraint programming model for resource-constrained assembly line balancing problem(SPRINGER, 2020) Alakas, Haci Mehmet; Pinarbasi, Mehmet; Yuzukirmizi, MustafaThe literature studies assume that resources used to be perform the tasks are certain and homogenous in any assembly line. However, tasks may need to be processed by general resource requirements in real life. These general resources could be classified by usage of resources such as simple or multiple, alternative and concurrent. The problem which is related to assignment of the task to any workstation and assignment of resources needed by the task simultaneously is defined as resource-constrained assembly line balancing problems (RCALBPs). In this study, a multiobjective model with minimization of cycle time and resource usage for a given number of stations is modeled to solve the RCALBP for the first time. Alternative and general resource types for tasks and using more than two resource type requirements are also considered. A constraint programming model is developed and solved to find the optimal solutions of these problems. The proposed models are tested with sample scenarios to show the effectiveness of the model.Öğe Determination of Bid Values for High Speed Train Superstructure Tenders by Game Theory(Turkish Chamber Civil Engineers, 2022) Alakas, Haci Mehmet; Kacar, Cem; Yazici, EmreThe use of high-speed trains (YHT) is increasing for the world's speed and competitiveness in rail transport. In Turkey, new lines have been built for the development of the railway in recent years. This study, it is aimed to create a mathematical model to determine the final bid price in the superstructure and electromechanical construction works of the YHT lines built in Turkey. Game theory was used to analyze the conflict of interest between contractors or bidders in the mathematical model. In the model, the bid distributions were determined by using the bids given in the previous bids. To minimize the degree of the winner's curse in determining the final bid price, a mathematical model is proposed using an empirical approach, using past bids. The competitive final bid price of the superstructure and electromechanical works of the superstructure and electromechanical works of the new YHT railway lines can be calculated in the standards of the previous tenders examined with the mathematical model.Öğe Determining Ergonomic Risks Arising from the Use of Information Technologies in the Covid-19 Environment(Taylor & Francis Inc, 2023) Aksut, Guler; Alakas, Haci Mehmet; Eren, TamerDue to the coronavirus (COVID-19) emerging in Wuhan, China, most employees had to work from home in unsuitable conditions. Employees are more affected by the factors that cause musculoskeletal disorders when working from home using information and communication technologies. The aim of the study was to determine the ergonomic risks related to the musculoskeletal system that teachers, who made up a large number of employees working in the service sector during the COVID-19 period, may be exposed to working remotely. For this, first of all, in line with the literature review and expert opinions, physical, psychosocial, and individual risk factors related to the musculoskeletal system were determined and the weight of the risk factors was calculated with the Analytic Network Process method. Work duration, posture, and physical environment constituted the highest risk factor among physical factors. With the Preference Ranking Organization Method for Enrichment Evaluations, information and communication devices were ranked according to their effects on the user. The ranking is determined by mobile phones, tablets, laptops, and desktop computers. It is concluded that it is necessary to pay attention to the risk factors specified in the use of these devices in order to prevent musculoskeletal system damage.Öğe Evaluation of natech criteria in organized industrial zones: An application for Kirikkale province(Elsevier Sci Ltd, 2024) Guven, Emel; Pinarbasi, Mehmet; Alakas, Haci Mehmet; Eren, TamerNatural disasters are unexpected natural events that cause severe property loss and moral damage. T & uuml;rkiye has been exposed to many disasters due to its location. One of the disasters experienced is the Kahramanmaras , earthquake that occurred on February 6th, 2023, in the recent past. Two consecutive earthquakes caused significant loss of life and property. In addition, some technological accidents happened because of the earthquake. The biggest of these was the fire in the Iskenderun marina. After the earthquake, the big fire that started with the fire of the containers on the quay could be brought under control after a long effort and time. Although it is often overshadowed by natural disasters, technological accidents triggered by natural disasters (Natech) accidents can cause severe damage. Especially Organized Industrial Zones (OIZ) are in areas with high Natech risk. This study determined 10 criteria that will cause Natech accidents for OIZs by literature review. The Pythagorean Fuzzy Analytical Hierarchy Process (PFAHP) method is used to weight the criteria. Then, a ranking is made using The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method among the five sectors operating in Kirikkale OIZ and which may have Natech risk.Öğe Evaluation of supply sustainability of vaccine alternatives with multi-criteria decision-making methods(Wiley, 2022) Yazici, Emre; Uner, Sabire Irem; Demir, Asli; Dinler, Sevda; Alakas, Haci MehmetBackground: The treatment of the COVID-19 epidemic, whose contagious features are changing day by day, is the most current problem today throughout of the world. In order to be protected from COVID-19 and reduce its spread, it is of great importance to follow the rules such as mask, distance and hygiene. In addition, one of the most important ways to prevent the epidemic is to develop population immunity. The most important tool in having population immunity is vaccination. Aims: During the COVID-19 pandemic, there have been problems in the supply process of many products in food and health sectors. Vaccine is also one of the most difficult tools to supply. In this context, the study focused on the selection of the vaccine provided by the countries within the scope of population vaccination studies. Materials & Methods: At the selection point, the criteria affecting the purchasing process were determined and the weights of these criteria were calculated using the AHP method. Then, the criteria weights obtained were used to rank the alternatives in an integrated manner in the Preference Ranking Organization Method for Enrichment of Evaluations (PROMETHEE) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) methods. The results of both methods were analyzed comparatively. Results: According to the TOPSIS Method, the first alternative is Oxford-AstraZeneca for all countries, and BioNTech for all countries in the PROMETHEE method. Discussion: The vaccine storage conditions criterion is the most important in vaccine supply. The criterion with the lowest importance is Supply Cost. It has been revealed that cost elements remain in the background under pandemic conditions. Conclusion: Vaccine evaluation studies and policy recommendations are presented by considering public health in the selection of vaccine alternatives.Öğe Evaluation of the companies for applied education under fuzzy environment: a case in an industrial university(Springer London Ltd, 2023) Ciftci, Sema; Pinarbasi, Mehmet; Yazici, Emre; Alakas, Haci MehmetNowadays, the problem of university graduates being unemployed is gradually increasing. To keep down unemployment, universities are integrating the concept of applied education into their educational curricula. The concept of applied education brings with it the problem of the correct student-company matching. In this study, the company selection criteria were focused on to determine the companies that university students will be sent to within the scope of applied education. Company selection criteria are determined by experts in the field. However, the evaluation of experts with precise criteria values can be very challenging in the decision-making process. For this purpose, the criteria weights were calculated using the Pythagorean Fuzzy AHP method in this study. Evaluation of companies to which students will be matched for applied/workplace education is ranked with these fuzzy weights by using TOPSIS and PROMETHEE II methods. To evaluation the proposed decision process, a real case study is carried out in an industrial private university in Turkey. The case study results show that the proposed method can provide effective and consistent results in the evaluation of companies under fuzzy environment.Öğe General resource-constrained assembly line balancing problem: conjunction normal form based constraint programming models(Springer, 2021) Alakas, Haci MehmetIn the literature, most of the researchers studying assembly line balancing have only considered task assignments. However, resources are needed to perform the tasks. Therefore, assigning resources related to tasks becomes more realistic when assigning tasks to stations. In the general case of the problem, the task is performed with a specified amount of resources. If resource types such as a, b, c are required to perform tasks in an assembly line, the combination of tasks required from these resources should also be assigned to the stations. This type of problem is defined as general resources-constrained assembly line balancing problem (GRCALBP). In this study, GRCALBP is addressed to minimize cycle time and resource usage for a given number of stations. New constraint programming (CP) models based on conjunction normal form are proposed. The CP models are tested with generated problem instances from the data set in the literature. The experimental results show that CP is an efficient and effective modeling technique to solve GRCALBP. Finally, suggestions are made regarding alternative objective functions.Öğe Goal programming models for high-speed train crew scheduling problem(Springer, 2023) Alakas, Haci Mehmet; Eren, Tamer; Yelek, Ayse; Ozder, Emir HuseyinHigh freight and passenger-carrying capacity, providing a fast and safe journey, and its tourism potential, railway transportation remains preferable among transportation types. Many personnel perform different tasks such as operation, administration, maintenance, security, and cleaning on the railways to provide an excellent service to the passengers. These personnel are among the most critical parts of the railway system in infrastructure, passenger, and freight transport. This study aims to create a schedule by using mathematical methods for the personnel working in the railway system. The goal programming method, which enables to achieve more than one goal simultaneously, was used to solve the problem. It is planned to create the most appropriate and efficient work plan by analyzing the work, task distribution, and shift schedules of the personnel working on the high-speed railway (HSR) Ankara-Istanbul line. The 28 day team schedule, which aims to distribute the duties of the staff equally, includes the distribution of the teams and the creation of tours for a total of sixteen daily trips. 225 crew working between Ankara-Istanbul and Istanbul-Ankara were formed. We gathered a fair schedule for the crew, and we increased the satisfaction level of the personnel. While all this is being done, the business requests were met.Öğe Harvest optimization for sustainable agriculture: The case of tea harvest scheduling(Keai Publishing Ltd, 2023) Sarimehmet, Bedirhan; Pinarbasi, Mehmet; Alakas, Haci Mehmet; Eren, TamerTo ensure sustainability in agriculture, many optimization problems need to be solved. An important one of them is harvest scheduling problem. In this study, the harvest scheduling problem for the tea is discussed. The tea harvest problem includes the creating a harvest schedule by considering the farmers' quotas under the purchase location and factory capacity. Tea harvesting is carried out in cooperation with the farmer -factory. Factory management is interested in using its resources. So, the factory capacity, purchase location capacities and number of expeditions should be considered during the harvesting process. When the farmer's side is examined, it is seen that the real professions of farmers are different. On harvest days, farmers often cannot attend to their primary professions. Considering the harvest day preferences of farmers in creating the harvest schedule are of great importance for sustainability in agriculture. Two different mathematical models are proposed to solve this problem. The first model minimizes the number of weekly expeditions of factory vehicles within the factor and purchase location capacity restrictions. The second model minimizes the number of expeditions and aims to comply with the preferences of the farmers as much as possible. A sample application was performed in a region with 12 purchase locations, 988 farmers, and 3392 decares of tea fields. The results show that the compliance rate of farmers to harvesting preferences could be increased from 52% to 97%, and this situation did not affect the number of expeditions of the factory. This result shows that considering the farmers' preferences on the harvest day will have no negative impact on the factory. On the contrary, it was concluded that this situation increases sustainability and encouragement in agriculture. Furthermore, the results show that models are effective for solving the problem.(c) 2023 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Öğe Post-Disaster Temporary Storage Location Selection and Multi-Vehicle Vehicle Routing Application: An Case in Kirikkale Province(Gazi Univ, 2023) Tezcan, Burcu; Alakas, Haci Mehmet; Özcan, Evrencan; Eren, TamerIt is unclear when and where disasters will occur. Therefore, both social life is interrupted and it harms the environment. In addition, after the disaster, people's needs such as food, shelter and cleaning should be met quickly and regularly. In order to meet the needs of people in disasters that cause great damage such as earthquakes and make many places unusable, the temporary warehouse should be located. Therefore, the locations of the temporary storage should be determined using appropriate analytical methods before an earthquake occurs. Kirikkale is a city with high probability of earthquakes due to its distance to fault zones. This, as well as production facilities are located within the boundaries of Turkey's major strategic industry. The fact that 43 provinces are the intersection point, especially its proximity to Ankara and the large industrial establishments located between Ankara increase the importance of the temporary warehouse to be located in Kirikkale in a possible earthquake outside Kirikkale. In this study, the problem of temporary warehouse location selection in Kirikkale province has been addressed in 3 stages. In the first stage, four alternative districts were compared, in the second stage, six alternative locations were compared by using multi-criteria decision-making methods. After determining the location of the temporary warehouse, in the third stage, the routes through which the food distribution will be distributed were determined with four different scenarios. In this study, a integrated approach for warehouse location selection and distribution planning is proposed to the literature.Öğe Problem Specific Variable Selection Rules for Constraint Programming: A Type II Mixed Model Assembly Line Balancing Problem Case(TAYLOR & FRANCIS INC, 2020) Alakas, Haci Mehmet; Toklu, BilalABSRACT The main idea of constraint programming (CP) is to determine a solution (or solutions) of a problem assigning values to decision variables satisfying all constraints. Two sub processes, an enumeration strategy and a consistency, run under the constraint programming main algorithm. The enumeration strategy which is managing the order of variables and values to build a search tree and possible solutions is crucial process in CP. In this study problem-based specific variable selection rules are studied on a mixed model assembly line balancing problem. The 18 variable selection rules are generated in three main categories by considering the problem input parameters. These rules are tested with benchmark problems in the literature and experimental results are compared with the results of mathematical model and standard CP algorithm. Also, benchmark problems are run with two CP rules to compare experimental results. In conclusion, experimental results are shown that the outperform rules are listed and also their specifications are defined to guide to researchers who solve optimization problems with CP.Öğe Ranking Of Sustainability Criteria For Industrial Symbiosis Applications Based On Anp(VILNIUS GEDIMINAS TECH UNIV, 2020) Alakas, Haci Mehmet; Gur, Seyda; Ozcan, Evrencan; Eren, TamerEnterprises have started to establish partnerships both to use their internal resources efficiently and to increase their environmental performance. Partnerships and interoperability of enterprises with different processes enable them to benefit more from their benefits. Moving towards the local and regional economy, these partnerships that increase environmental and own resources have created industrial symbiosis practices. Industrial ecology fields are established in these applications. Both environmental and economic gains can be achieved through the efficient use of resources by enterprises and the minimization of wastes. For the sustainability of these partnerships to be established by enterprises, they need to analyze the measures they take internally. In this study, the concept of industrial symbiosis and the criteria that are effective for the sustainability of these industrial symbiosis are evaluated. Analytical network process method is used. Thus, the industrial symbiosis infrastructures to be established by enterprises have been enabled to move strategically.Öğe Shift Scheduling with the Goal Programming Method: A Case Study in the Glass Industry(Mdpi, 2019) Kacmaz, Ozlem; Alakas, Haci Mehmet; Eren, TamerNowadays, resource utilization and management are very important for businesses. They try to make a profit by providing high levels of efficiency from available sources. Their labor force is one of these sources. Therefore, scheduling based on personnel satisfaction has become an important problem in recent years. In this study, a case study was carried out in a glass factory in Ankara which has 7 department and 80 personnel. The aim of the study is to provide better service by distributing personnel to shifts in a fair and balanced manner. Assignment points are different for the departments where the personnel will work. Every personnel member is assigned to the department as best as possible. A goal programming method was used, and the results were better than those obtained using other methods.Öğe Surgical Operation Scheduling with Goal Programming and Constraint Programming: A Case Study(Mdpi, 2019) Gur, Seyda; Eren, Tamer; Alakas, Haci MehmetThe achievement of health organizations' goals is critically important for profitability. For this purpose, their resources, materials, and equipment should be efficiently used in the services they provide. A hospital has sensitive and expensive equipment, and the use of its equipment and resources needs to be balanced. The utilization of these resources should be considered in its operating rooms, as it shares both expense expenditure and revenue generation. This study's primary aim is the effective and balanced use of equipment and resources in hospital operating rooms. In this context, datasets from a state hospital were used via the goal programming and constraint programming methods. According to the wishes of hospital managers, three scenarios were separately modeled in both methods. According to the obtained results, schedules were compared and analyzed according to the current situation. The hospital-planning approach was positively affected, and goals such as minimization cost, staff and patient satisfaction, prevention over time, and less use were achieved.
