Endüstri Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/279
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Article Citation - WoS: 23Citation - Scopus: 24Bi-Objective Dynamic Weapon-Target Assignment Problem With Stability Measure(Springer, 2022) Karasakal, Esra; Karasakal, Orhan; Silav, AhmetIn this paper, we develop a new bi-objective model for dynamic weapon-target assignment problem. We consider that the initial weapon assignment plan of defense is disrupted during engagement because of a destroyed air target, breakdown of a weapon system or a new incoming air target. The objective functions are defined as the maximization of probability of no-leaker and the maximization of stability in engagement order of weapon systems. Stability is defined as assigning same air target in sequence in engagement order of a weapon system so that reacquisition and re-tracking of air target are not required by sensors. We propose a new solution procedure to generate updated assignment plans by maximizing efficiency of defense while maximizing stability through swapping weapon engagement orders. The proposed solution procedure generates non-dominated solutions from which defense can quickly choose the most-favored course of action. We solve a set of representative problems with different sizes and present computational results to evaluate effectiveness of the proposed approach.Article Citation - WoS: 8Citation - Scopus: 12A Multi-Objective Approach for Dynamic Missile Allocation Using Artificial Neural Networks for Time Sensitive Decisions(Springer, 2021) Karasakal, Esra; Silav, Ahmet; Karasakal, OrhanIn this study, we develop a new solution approach for the dynamic missile allocation problem of a naval task group (TG). The approach considers the rescheduling of the surface-to-air missiles (SAMs), where a set of them have already been scheduled to a set of attacking anti-ship missiles (ASMs). The initial schedule is mostly inexecutable due to disruptions such as neutralization of a target ASM, detecting a new ASM, and breakdown of a SAM system. To handle the dynamic disruptions while keeping efficiency high, we use a bi-objective model that considers the efficiency of SAM systems and the stability of the schedule simultaneously. The rescheduling decision is time-sensitive, and the amount of information to be processed is enormous. Thus, we propose a novel approach that supplements the decision-maker (DM) in choosing a Pareto optimal solution considering two conflicting objectives. The proposed approach uses an artificial neural network (ANN) that includes an adaptive learning algorithm to structure the DM's prior articulated preferences. ANN acts like a DM during the engagement process and chooses one of the non-dominated solutions in each rescheduling time point. We assume that the DM's utility function is consistent with a non-decreasing quasi-concave function, and the cone domination principle is incorporated into the solution procedure. An extensive computational study is provided to present the effectiveness of the proposed approach.Article Citation - WoS: 16Citation - Scopus: 24A Decision Support System for Locating Weapon and Radar Positions in Stationary Point Air Defence(Springer, 2012) Maras, Hakan; Gencer, Cevriye; Aygunes, Haluk; Tanerguclu, TurkerIn this study, a decision support system (DSS) based on the interactive use of location models and geographical information systems (GIS) was developed to determine the optimal positions for air defence weapons and radars. In the location model, the fire units are considered as the facilities to be located and the possible approach routes of air vehicles are treated as demand points. Considering the probability that fire by the units will miss the targets, the objective of the problem is to determine the positions that provide coverage of the approach routes of the maximum number of weapons while considering the military principles regarding the tactical use and deployment of units. In comparison with the conventional method, the proposed methodology presents a more reliable, faster, and more efficient solution. On the other hand, owing to the DSS, a battery commander who is responsible for air defence becomes capable of determining the optimal weapon and radar positions, among the alternative ones he has identified, that cover the possible approach routes maximally. Additionally, he attains the capability of making such decisions in a very short time without going to the field over which he will perform the defence and hence without being subject to enemy threats. In the decision support system, the digital elevation model is analysed using Map Objects 2.0, the mathematical model is solved using LINGO 4.0 optimization software, and the user interface and data transfer are supported by Visual Basic 6.0.Article Citation - WoS: 30Citation - Scopus: 38Intermodal Humanitarian Logistics Model Based on Maritime Transportation in Istanbul(Springer, 2016) Aygunes, Haluk; Ozkapici, Dilsu Binnaz; Ertem, Mustafa AlpIstanbul, the economic capital and most populated city of Turkey, is highly prone to earthquakes. When an earthquake occurs, required relief items are expected to be supplied from national and international sources. To alleviate human suffering following an earthquake, in this paper, we propose an intermodal relief item distribution model for Istanbul involving sea and land transportation with identified road vulnerabilities. The proposed mathematical model utilizes the seaports of Istanbul for maritime transportation and allows for the transportation of relief item between Istanbul's European and Anatolian sides. We also use the seabasing concept for providing supplies to demand areas. The use of maritime transportation and seabasing provides flexibility for humanitarian logistical activities and the proposed model provides an effective and reliable disaster relief system for Istanbul as well as other disaster-prone cities with significant maritime transportation components.Article Citation - WoS: 6Citation - Scopus: 7An Approximation for Kanban Controlled Assembly Systems(Springer, 2011) Avsar, Zeynep Muge; Topan, EnginAn approximation is proposed to evaluate the steady-state performance of kanban controlled two-stage assembly systems. The development of the approximation is as follows. The considered continuous-time Markov chain is aggregated keeping the model exact, and this aggregate model is approximated replacing some state-dependent transition rates with constant rates. The approximate aggregate model is, then, decomposed into submodels and a product-form steady-state distribution is obtained for each submodel. Finally, the submodels are combined in such a way that the size of the problem becomes independent of the number of kanbans. This leads to the computational advantage in solving the combined model using numerical matrix-geometric solution algorithms. Numerical comparisons of the combined model with simulation, exact model, approximate aggregate model and an approximation in the literature show that the proposed approximation performs well in terms of accuracy and computational burden.Article Citation - WoS: 1Citation - Scopus: 1Utilization of Triso Fuel With Lwr Spent Fuel in Fusion-Fission Hybrid Reactor System(Springer, 2010) Altunok, Taner; Acir, AdemHTRs use a high performance particulate TRISO fuel with ceramic multi-layer coatings due to the high burn up capability and very neutronic performance. TRISO fuel because of capable of high burn up and very neutronic performance is conducted in a D-T fusion driven hybrid reactor. In this study, TRISO fuels particles are imbedded body-centered cubic (BCC) in a graphite matrix with a volume fraction of 68%. The neutronic effect of TRISO coated LWR spent fuel in the fuel rod used hybrid reactor on the fuel performance has been investigated for Flibe, Flinabe and Li(20)Sn(80) coolants. The reactor operation time with the different first neutron wall loads is 24 months. Neutron transport calculations are evaluated by using XSDRNPM/SCALE 5 codes with 238 group cross section library. The effect of TRISO coated LWR spent fuel in the fuel rod used hybrid reactor on tritium breeding (TBR), energy multiplication (M), fissile fuel breeding, average burn up values are comparatively investigated. It is shown that the high burn up can be achieved with TRISO fuel in the hybrid reactor.Article Citation - WoS: 21Citation - Scopus: 24Effects of Electrospinning Process Parameters on Nanofibers Obtained From Nylon 6 and Poly (ethylene-N Acrylate-Maleic Anhydride) Elastomer Blends Using Johnson Sb Statistical Distribution Function(Springer, 2010) Biber, Erkan; Gunduz, Gungor; Mavis, Bora; Colak, UnerThe impact strength of Nylon 6 can be further improved by blending it with ethylene-butyl acrylate-maleic anhydride elastomer. The blending is achieved in solution phase. Due to incompatibility of Nylon 6 and the elastomer, a special mixture of solvents is used to dissolve both components. The solution is electrospun, and the effects of the process parameters on the expected radii of nanofibers are investigated. The effects of process parameters such as polymer concentration in solution, electrical field, diameter of the syringe needle, feed rate, and collector geometry on nanofibers were investigated. Statistical analysis is carried out using the Johnson S-B distribution. A relation is proposed to relate the effect of the process parameters feed rate, electrical voltage, and tip to collector distance on the expected diameter of fibers. It is found that concentration and electrical field have a profound effect on the diameter of fibers compared to those of the syringe diameter and feed rate.