Endüstri Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/279
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Article Citation - Scopus: 8A Partial Coverage Hierarchical Location Allocation Model for Health Services(Inderscience Publishers, 2023) Karasakal, O.; Karasakal, E.; Töreyen, Ö.We consider a hierarchical maximal covering location problem (HMCLP) to locate health centres and hospitals so that the maximum demand is covered by two levels of services in a successively inclusive hierarchy. We extend the HMCLP by introducing the partial coverage and a new definition of the referral. The proposed model may enable an informed decision on the healthcare system when dynamic adaptation is required, such as a COVID-19 pandemic. We define the referral as coverage of health centres by hospitals. A hospital may also cover demand through referral. The proposed model is solved optimally for small problems. For large problems, we propose a customised genetic algorithm. Computational study shows that the GA performs well, and the partial coverage substantially affects the optimal solutions. © 2023 Inderscience Enterprises Ltd.Article Citation - WoS: 2Citation - Scopus: 2Naval Air Defense Planning Problem: a Novel Formulation and Heuristics(Wiley, 2024) Karasakal, Orhan; Kirca, Oemer; Arslan, CanerThis article focuses on air defense in maritime environment, which involves protecting friendly naval assets from aerial threats. Specifically, we define and address the Naval Air Defense Planning (NADP) problem, which consists of maneuvering decisions of the ships and scheduling weapons and sensors to the threats in order to maximize the total expected survival probability of friendly units. The NADP problem is more realistic and applicable than previous studies, as it considers features such as sensor assignment requirements, weapon and sensor blind sectors, sequence-dependent setup times, and ship's infrared/radar signature. In this study, a mixed-integer nonlinear programming model of the NADP problem is presented and heuristic solution approaches are developed. Computational results demonstrate that these heuristic approaches are both fast and efficient in solving the NADP problem.Article Design of a Distribution Network for the School Lunch Program(Academic Publication Council, 2023) Aydemir-Karadag, Ayyuce; Akdere, Erol; Karadag, Ayyuce AydemirThe national school lunch program (NSLP) is crucial for providing healthy, inexpensive, or free lunches to children, thus benefiting society. Designing a distribution network for the program requires solving a location and routing problem. In this paper, first, we formulate a multi -objective non-linear integer programming formulation of the problem. Next, we develop a two-step approach since the problem is Np-hard. The first stage presents a K -mean clustering method that deals with routing decisions by determining the locations of food processing centers and allocating schools to these centers. The second stage offers a multi -objective mixed -integer linear mathematical model for finding the locations of distribution centers. Besides economic and environmental factors, we optimize travel time in the network as perishable items are involved. A weighted sum approach is presented for different weights of objectives. We provide a real case study in Turkey to demonstrate the applicability of the two -stage approach proposed in this study. The numerical results provide valuable information for decision -makers and authorities to prioritize and prepare action plans.Article Citation - WoS: 5Citation - Scopus: 3Optimum Bidding Strategy for Wind and Solar Power Plants in Day-Ahead Electricity Market(Springer Heidelberg, 2021) Keysan, Ozan; Satir, Benhur; Ozcan, MehmetThere are two possible strategies for wind power plants (WPPs) and solar power plants (SPPs) to maximize their income in day ahead markets (DAM) in the presence of imbalance cost: joint bidding (JB) via collaboration by participating to balancing groups and deployment of storage technologies. There are limited studies in the literature covering the comparative analysis of "JB strategy" with "battery deployment (BD) strategy". In the existence of balancing responsibility, the comparative analysis of these strategies is the main contribution of this study to the literature. Our Second contribution is the analysis of the impact of different regulatory regimes, which are set by the regulatory authority, on total income. JBM (joint bidding model), which is the model for joint bidding via different collaboration groups, is developed for the analysis of JB strategy, BDM (battery deployment model), which is the model covering the deployment of storage technology, is developed for the analysis of BD strategy. The impact of each strategy on total income is analyzed. According to the analysis of the results of the models, while JB strategy, which is sensitive to the regulatory regime, increases the total annual income of the collaboration groups up to 0.65%, BD strategy seems not feasible and financially viable. On the other hand, extra income values per MW of battery for SPP is between $218 and $400 /MW-year, while these values are between $2460 and $6795/MW-year for the group of 15 WPPs. Therefore, deployment of battery for WPPs creates extra income more than tenfold of that of SPP. BD strategy can be viable provided that the levelized cost of deployment of battery drops below the extra income values achieved per MW of battery.Article Control of trichloroethylene emissions from sparging systems by horizontal bio- and chemo- barriers(2005) Tezel, U.; Demirer, G.N.; Uludag, Demirer S.The scope of this study was to develop a continuous system to clean-up a trichloroethylene (TCE) contaminated gas stream, where biotic and abiotic removal mechanisms are undertaken sequentially simulating the horizontal bio- and chemo-barriers proposed for the in-situ remediation of the contaminated sites. The bio- and chemo-barriers were simulated by using glass columns packed with granular anaerobic mixed culture and Fe(0) filings, respectively. The effect of gas residence time, which is adjusted by the gas flowrate, on the TCE removal efficiency of the reactor system was investigated. TCE removal efficiency of over 90% was achieved at gas residence times above 1hr. Furthermore, the effluent of reactor system contained only ethane and ethylene, which are non-toxic by-products of TCE reduction reactions, along with trace amounts of TCE.Article Minisum and maximin aerial surveillance over disjoint rectangles(2016) Karasakal, OrhanThe aerial surveillance problem (ASP) is finding the shortest path for an aerial surveillance platform that has to visit each rectangular area once and conduct a search in strips to cover the area at an acceptable level of efficiency and turn back to the base from which it starts. In this study, we propose a new formulation for ASP with salient features. The proposed formulation that is based on the travelling salesman problem enables more efficient use of search platforms and solutions to realistic problems in reasonable time. We also present a max–min version of ASP that maximizes the minimum probability of target detection given the maximum flight distance of an aerial platform. We provide computational results that demonstrate features of the proposed models.Article Citation - WoS: 12Analysis of Dengue Transmission Dynamic Model by Stability and Hopf Bifurcation With Two-Time Delays(Imr Press, 2023) Ambalarajan, Venkatesh; Sivakumar, Vinoth; Dhandapani, Prasantha Bharathi; Baleanu, Dumitru; Murugadoss, Prakash RajBackground: Mathematical models reflecting the epidemiological dynamics of dengue infection have been discovered dating back to 1970. The four serotypes (DENV-1 to DENV-4) that cause dengue fever are antigenically related but different viruses that are transmitted by mosquitoes. It is a significant global public health issue since 2.5 billion individuals are at risk of contracting the virus. Methods: The purpose of this study is to carefully examine the transmission of dengue with a time delay. A dengue transmission dynamic model with two delays, the standard incidence, loss of immunity, recovery from infectiousness, and partial protection of the human population was developed. Results: Both endemic equilibrium and illness-free equilibrium were examined in terms of the stability theory of delay differential equations. As long as the basic reproduction number (R0) is less than unity, the illness-free equilibrium is locally asymptotically stable; however, when R0 exceeds unity, the equilibrium becomes unstable. The existence of Hopf bifurcation with delay as a bifurcation parameter and the conditions for endemic equilibrium stability were examined. To validate the theoretical results, numerical simulations were done. Conclusions: The length of the time delay in the dengue transmission epidemic model has no effect on the stability of the illness-free equilibrium. Regardless, Hopf bifurcation may occur depending on how much the delay impacts the stability of the underlying equilibrium. This mathematical modelling is effective for providing qualitative evaluations for the recovery of a huge population of afflicted community members with a time delay.Article A Partial Coverage Hierarchical Location Allocation Model for Health Services(inderscience Enterprises Ltd, 2023) Karasakal, Esra; Toreyen, Ozgun; Karasakal, OrhanWe consider a hierarchical maximal covering location problem (HMCLP) to locate health centres and hospitals so that the maximum demand is covered by two levels of services in a successively inclusive hierarchy. We extend the HMCLP by introducing the partial coverage and a new definition of the referral. The proposed model may enable an informed decision on the healthcare system when dynamic adaptation is required, such as a COVID-19 pandemic. We define the referral as coverage of health centres by hospitals. A hospital may also cover demand through referral. The proposed model is solved optimally for small problems. For large problems, we propose a customised genetic algorithm. Computational study shows that the GA performs well, and the partial coverage substantially affects the optimal solutions. [Submitted: 20 January 2021; Accepted: 15 January 2022]Article Citation - WoS: 4Citation - Scopus: 10Customer Order Scheduling With Job-Based Processing on a Single-Machine To Minimize the Total Completion Time(Growing Science, 2021) Yeloglu, Pinar; Catmakas, Hale Akkocaoglu; Cetinkaya, Ferda CanThis study considers a customer order scheduling (COS) problem in which each customer requests a variety of products (jobs) processed on a single flexible machine, such as the computer numerical control (CNC) machine. A sequence-independent setup for the machine is needed before processing each product. All products in a customer order are delivered to the customer when they are processed. The product ordered by a customer and completed as the last product in the order defines the customer order's completion time. We aim to find the optimal schedule of the customer orders and the products to minimize the customer orders' total completion time. We have studied this customer order scheduling problem with a job-based processing approach in which the same products from different customer orders form a product lot and are processed successively without being intermingled with other products. We have developed two mixed-integer linear programming models capable of solving the small and medium-sized problem instances optimally and a heuristic algorithm for large-sized problem instances. Our empirical study results show that our proposed tabu search algorithm provides optimal or near-optimal solutions in a very short time. We have also compared the job-based and order-based processing approaches for both setup and no-setup cases and observed that the job-based processing approach yields better results when jobs have setup times. (C) 2021 by the authors; licensee Growing Science, CanadaArticle Citation - WoS: 3Citation - Scopus: 4Comparison of Classroom Furniture To Anthropometric Measures of Turkish Middle School Students(Ios Press, 2021) Erdogan, Filiz Celikci; Satir, BenhurBACKGROUND: The match between classroom furniture and students' anthropometry is an important factor in students' academic performance. OBJECTIVE: Our aim was to investigate the ergonomic suitability of the classroom furniture to the students, and to propose design suggestions for both desks and chairs. METHODS: We analyzed the ergonomics of classroom furniture that students aged 10-14 years old in Turkey currently use. To this end, we selected Maltepe Primary Education School, one of the largest schools in the cankaya district of Turkey's capital city, Ankara, in which to conduct the study. A sample of 119 students was selected, and seven anthropometric measurements were taken for each of these students. We then calculated five relationships between the dimensions of the furniture and the students' anthropometric measures. RESULTS: We observed high levels of mismatch rates, with an average of 66.6% and high values of over 95% for the relations of two furniture measures, seat depth (related with buttock-popliteal length) and seat-to-desk height (related with elbow height, sitting). Each anthropometric measure was applied a fit probability distribution, and based on those distributions; we suggested the most appropriate classroom furniture dimensions in order to maximize suitability of the furniture to the anthropometric measures in terms of fixed-size (i.e., non-adjustable) classroom furniture. CONCLUSIONS: High mismatch rates can be reduced by 52.0% on average based on the classroom furniture dimensions suggested in this study.
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