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Item How hematopoietic stem cell transplantation activity was affected during the pandemic? JACIE accredited center reflex(2022) Kozanoglu, I.; Tepebasi, S.; Kursun, E.; Sen, N.; Unsal, Z. E.; Kis, C.; Boga, C.; Yesilagac, H.; Demiroglu, Y. Z.; Pocan, G.Item TBI/fludarabine versus busulfan/fludarabine as a myeloablative conditioning for adults with acute myeloid leukemia treated with allo-HCT. A study from the ALWP of the EBMT(2022) Swoboda, R.; Labopin, M.; Giebel, S.; Schroeder, T.; Kroeger, N.; Arat, M.; Savani, B.; Spyridonidis, A.; Hamladji, R. M.; Potter, V.; Deconinck, E.; Yakoub-Agha, I.; Rambaldi, A.; Ozdogu, H.; Sanz, J.; Nagler, A.; Mohty, M.Item Estimating the COVID-19 Death Counts Using a Hesitant Fuzzy Linear Regression Depend on Race, Age and Location(2022) Dengiz, Asiye Ozge; Atalay, Kumru DidemThe COVID-19 pandemic that has struck the world has caused social and economic problems in people's lives. Many countries are trying to reduce the impact of the pandemic by taking precautions to prevent the spread of the virus and reduce the number of deaths. Despite the precautions, many people have contracted the virus and a significant number have lost their lives. This suggests that some factors about the exact mechanism of how people contract the virus and get sick are still unclear. Therefore, many researchers wonder if there are other factors that make people more susceptible to the COVID-19 virus. In this study, hesitant fuzzy linear regression (HFLR) models are applied depending on variables such as age, race, and place of residence that are thought to influence COVID-19 deaths. HFLR provides an alternative approach to statistical regression for modeling situations with incomplete information. The models include input and output variables as hesitant fuzzy elements (HFEs). The relationship between the considered variables and the number of deaths is examined using data related to people living in different states of the United States. In addition, HFLR is used as an estimation model due to the uncertainty in the data obtained from the Centers for Disease Control and Prevention (CDC). The proposed HFLR models are used both to estimate COVID-19 deaths and to determine the effects of selected variables on COVID-19 deaths. In this way, countries can estimate the risk of death for individuals given these factors and determine what precautions to take for high-risk groups.Item Risk Analysis and Process Improvement for Medical Devices with Integrated Method DEA and FMEA(2022) Yamandir, Merve Nil; Dinler, Esra; Atalay, Kumru DidemRisk analysis is the identification of factors, conditions, activities, systems, components that are important concerning risk. Evaluating the systems in terms of risk plays a critical role in the production of products that are especially important for human health. The washing process of the medical devices at the production stage is important in terms of ensuring the acceptable sterility assurance level of the product before sterilization. In this process, the risk factors that may affect human health emerge. Risk Priority Number (RPN) which is used in the Failure Mode and Effect Analysis (FMEA) is calculated for each factor and it is considered to be equally important in general. Sometimes it can be difficult to clearly show the importance of these effects. These invisible effects cause great costs for companies, and they can also affect human health at risk. In this study, risk analysis of the washing process in a company producing medical devices is performed. Risk prioritization is made by scaling risk types and their effects by Data Envelopment Analysis (DEA) method to eliminate the disadvantages in question. As a result of the study, the prioritization of risk types with different methods is compared.Item The Use of Petri Nets in Performance Analysis of Flexible Manufacturing Cell(2022) Bulca, Fatima Busra; Ic, Yusuf Tansel; Yurdakul, MustafaA Flexible Manufacturing Cell (FMC) is a system that consists of computer-integrated machines, automatic material handling systems, and robots. It produces different part types with minimal worker involvement. Many different methods, such as queuing systems and simulation models, have been applied in FMC modeling in the literature. This study aims to use Petri Nets (PN) in modelling complex FMCs. The study is carried out in the FMC located in the Advanced Manufacturing Systems Laboratory of Baskent University. The FMC consists of a CNC machining center, a material handling robot and a pallet, which has three work-piece carriage capacities. Processing times of FMC elements may vary due to reasons (the power usage performance, air supply efficiency, electrical power efficiency, etc.) arising from the mechanical structure of the system. This uncertainty needs to be taken into account when modeling the system. In this study, the uncertain (fuzzy) processing times associated with the transitions were caused by the mechanical structure of the system. In order to compare with the newly developed fuzzy models, the system was first modeled using Transition Time Petri Nets (TTPN), in which the running times associated with the transition times take precise values. On the other hand, for handling fuzzy values of the actual operating times in the FMC, two models namely, Partial-Fuzzy Transition Time Petri Nets (Partial-FTTPN) and Fuzzy Transition Time Petri Nets (FTTPN) are developed. The results of the three models are compared to analyze the benefits of combining "time uncertainties" resulting from the natural behavior of FMCs.Item A Genetic Algorithm for the Redundancy Allocation Problem with Repairable Components(2022) Sahin, Merve Uzuner; Dengiz, Orhan; Dengiz, BernaThe complexity of the structures of modern engineering systems in the communication and electronic fields, the demand for high reliable system evaluation methods has increased. While improving the system's reliability, the cost is also on the upswing. Redundancy allocation is important approach for designing telecommunication systems. The reliability is increased by increasing number of redundant components in a system. The Redundancy Allocation Problem (RAP) is the design of new systems with higher reliability using redundant components in parallel arrangement. This paper presents a genetic algorithm (GA) with discrete event simulation (DES) to solve RAP with repairable components. The promising proposed approach is illustrated and investigated by some RAP benchmark/test problems involving repairable systems.Item Traveling Repairmen Problem: A Biogeography-Based Optimization(2022) Uzun, Gozde Onder; Dengiz, Berna; Kara, Imdat; Karasan, Oya EkinTraveling Repairman Problem (TRP), which is also known by names cumulative traveling salesman problem, the deliveryman problem and the minimum latency problem, is a special variant of Traveling Salesman Problem (TSP). In contrast to the minimization of completion time objective of TSP, the desired objective of TRP is to minimize the cumulative latency (waiting time or delay time) of all customers. In this paper, a generalized version of TRP with multi depots and time windows, namely Multi Depot Traveling Repairman Problem with Time Windows (MDTRPTW) is considered. A group of homogeneous repairmen initiate and finish their visit tours at multiple depots. Each customer must be visited exactly by one repairman within their provided earliest end latest times. Being a challenging Nondeterministic Polynomial-hard (NP-hard) optimization problem, exact solution approaches are not expected to scale to realistic dimensions of MDTRPTW. Thus, we propose a biogeography-based optimization algorithm (BBOA) as a metaheuristic approach to solve large size MDTRPTW problems. The proposed metaheuristic is analyzed in terms of solution quality, coefficient of variation as well as computation time by solving some test problems adapted from the related literature. The efficacy of the proposed solution methodology is demonstrated by solving instances with 288 customers within seconds.Item Opposition-Based Variable Neighborhood Descent Algorithm for the Traveling Salesperson Problem with Hotel Selection(2022) Akpinar, Ipek Damla; Kececi, BarisIn this study, The Traveling Salesperson Problem with Hotel Selection (TSPHS) is considered. TSPHS includes daily working time/distance restrictions. This constraint does not allow visiting all points at once. For this reason, the traveler stops (roosts) at a suitable waiting point (hotel) at the end of the day and continues the next day's trip from the point (hotel) where he stayed. There is no obligation to visit each hotel, and a hotel can be visited more than once. A set of ordered nodes starting and ending at a hotel is called a trip, and a set of ordered trips covering all nodes is called a tour. The primary objective of the problem is to minimize the number of trips. The secondary objective is to minimize the total distance of the tour, provided that the time/distance per trip does not exceed the daily working time limit. Since this problem belongs to the NP-hard problem class, the use of the heuristic method has an advantage in terms of the solution time. In our solution approach, the initial solution is obtained using The Nearest Neighbor Algorithm (NN). To improve this solution, the Opposition-Based Variable Neighborhood Descent (OBVND) is used. The performance of the algorithm is evaluated on the test problems in the literature using various criteria. The results are compared with the best solutions available in the literature. The overall results show us that the proposed OBVND approach can find better quality solutions in 2 out of 16 problems in the Set 1 data; in 24 out of 52 problems in the Set 2 data; and in 9 out of 38 problems in Set 3 data.Item The Inventory of Flood Disasters in Turkey(2022) Gurer, Ibrahim; Ucar, IbrahimTurkey is located both Europe and Asia, and covers an area of 780 580 km(2) including the lakes. Turkey undergoes different types of natural disasters because of its geographical location, geomorphology, and topography. Flooding is the second important natural hazard after earthquakes. A flood inventory of the period extending from 1955 to 2020 having a total of about 3250 events was prepared using a simple computer program based on Excel for easy access to different geomorphologic parameters such as surface areas of river basins, slope, geological structure, vegetative cover, type of precipitation, and the elevation above mean sea level (a.m.s.l) and hydro-meteorological parameters. In the same inventory each flood has been defined with damages on human as lost and injured, size of flooded area and loss of wealth (not exact information for wealth). By categorization of the available data in hand, spatial and time distributions of past flood events were determined. In large basins, negative impacts are more closely related to climatic factors, but in small watersheds, the urbanization along the rivers, internal migration, regional planning, urban drainage infrastructure are more important on negative impacts. In order to prevent the floods and minimize the adverse effects to property, both structural and non-structural solutions are applied in Turkey. Two case studies added to show the solutions.Item Hydropower Outlook of Turkey in 2021(2022) Gurer, IbrahimTurkey is located partly on Europe and also on Asia, and has a surface area of 780 580 km(2) and a population of 84.6 million and electric energy is essential for the everyday life. The annual per capita consumption of electricity is mainly used to measure the prosperity of a nation. The energy use in a country increases not only with population increase but also by improving the living standards of people and industrial development. Turkey being a non-oil-producing country at present, therefore needs to import fossil fuels (like natural gas and fuel oil) as the main source of electric energy. The utilization of fossil fuels for energy production by thermal power plants is one of the main sources of air pollution. The consumption of imported energy sources should be reduced for the environmental, economic, and political reasons. As the electricity need of the country is increasing continuously, more energy from the renewables and national resources must be produced. Hydropower plants (HPPs) provide clean, fast, flexible electricity generation. The amount of electricity that aHPP can produce basically depends on the available flow rate (Q) and the head (H). Very briefly the greater the flow rate and the net head, the more electricity can be produced in a HPP. The first hydropower station of Turkey had been opened at Tarsus town in 1929. Number of hydropower installations and total installed capacity has increased especially after the 1960s. In 2020, the Turkish electric production values were 32.9% from HPPs, 27.2% from thermal plants working with natural gas, 21.3% from thermal plants working with coal, 8.8% fromwind power plants, 6.8% from the sun, 1.6% from geothermal plants, and about 1.4% from other types of sources. Technically and economically feasible total hydroelectric energy potential of Turkey is 180 billion kWh/year, of which 160 billion kWh/year has been developed and completed. With 714 completed facilities and 31,391 MW installed power and 108.0 billion kWh/year of it has been put into operation. With the projects to be established until 2023, a total installed power capacity of 40,000 MW and a generation potential of 135 billion kWh/year will be reached. Because of the very fast increase in energy consumption, and only 22% of total energy is produced from national sources, and 125 billion dollars total investment is needed. Due to the climate change, and the change in the oil prices, the renewable sources such as solar, wind, geothermal, biogas, biomass, hydropower etc. should be developed and put in service as quickly and efficiently as possible. In this paper, the current level of hydropower production and energy saving, and power consumption by different sectors, and the subject matter of the most recent energy figures are given and the future projections are also presented.