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Relief Aid Provision To En Route Refugees: Multi-Period Mobile Facility Location With Mobile Demand
No full textMany humanitarian organizations aid en route refugee groups who are on their journey to cross borders using mobile facilities and need to decide the number and routes of the facilities. We define a multi period facility location problem in which both the facilities and demand are mobile on a network. Refugee groups may enter and exit the network in different periods and follow various paths. In each period, a refugee group moves from one node to an adjacent one in their predetermined path. Each facility should be located at a node in each period and provides service to the refugees at that node. Each refugee should be served at least once in a predetermined number of consecutive periods. The problem is to locate the facilities in each period to minimize the total setup and travel costs of the mobile facilities, while ensuring the service requirement. We call this problem the multi-period mobile facility location problem with mobile demand (MM-FLP-MD) and prove its NP-hardness. We formulate a mixed integer linear programming (MILP) model and develop an adaptive large neighborhood search algorithm (ALNS) to solve large-size instances. We tested the computational performance of the MILP and the metaheuristic algorithm by extracting data from the 2018 Honduras Migration Crisis. For instances solved to optimality by the MILP model, the proposed ALNS determines the optimal solutions faster and provides better solutions for the remaining instances. By analyzing the sensitivity to different parameters, we provide insights to decision-makers.(c) 2021 Elsevier B.V. All rights reserved.This research was supported by TUBITAK [Grant number 119M229].TUBITAK [119M229
Deployment of a Uav-Mounted Intelligent Reflecting Surface in the Thz Band
No full text2022 International Balkan Conference on Communications and Networking, BalkanCom 2022 -- 22 August 2022 through 24 August 2022 -- 183326The design of RIS-assisted THz wireless systems is envisioned to be one of the key roles in 6G evolution. In this paper, we implement an analytical pathloss model for reconfigurable intelligent surface (RIS) in terahertz (THz) band. We study the optimal 3D deployment problem and configuration of UAV-Mounted RIS in THz band environment with the objective of maximizing the achievable rate of the network considering the distances from transmitter/receiver to the RIS, blockage probability, the far field constraints for unit cells and antennas, the size of the RIS, absorption loss and we provide a discussion that can serve as guidelines for researchers and mobile network operators for designing UAV-Mounted RIS in the THz Band. © 2022 IEEE
Development of a Method for Maximum Structural Response Prediction of a Store Externally Carried by a Jet Fighter
No full textExperimental structural response of equipment mounted in store carried externally by jet type aircraft is investigated, predicted and compared with responses suggested by military standards in this study. A representative store which is similar to Mark-83 warhead with guidance units in terms of mass and geometry is used in this study. The main scope of this study is to evaluate the structural response proposed by military standards with real test conditions and also suggest a new method with an artificial neural network to predict the maximum response. Seventy-five different flight conditions are used to train the network for low and high frequency components. Also, eight flight conditions apart from the training set of flight conditions are used to test the approach. Acceleration levels are collected in real flight conditions by the data storage system. In signal processing, vibration response is expressed as power spectral density functions in the frequency domain. Procedures to predict the maximum response from measurements are determined with statistical limits in the literature. Besides the well-known limits in literature, third-order polynomial normal and logarithmic transform is used, and the performance of the different limits is compared. It is found that the military standard vibration spectrum is conservative. Distribution-free and normal tolerance limits predicted low frequency acceleration spectral density magnitudes more accurately. Their prediction performances were better than those of the other tolerance limits and that of the military standard. Third-order polynomial transform predictions are found to be reasonable with respect to normal prediction limit and envelope approach. Finally, it can be concluded that the response prediction method proposed in this article works well for Mark-83 warheads with guidance unit carried externally by jet fighter. © IMechE 2021
A Multi-Modal Emotion Recognition System Based on Cnn-Transformer Deep Learning Technique
No full text7th International Conference on Data Science and Machine Learning Applications, CDMA 2022 -- 1 March 2022 through 3 March 2022 -- -- 177931Emotion analysis is a subject that researchers from various fields have been working on for a long time. Different emotion detection methods have been developed for text, audio, photography, and video domains. Automated emotion detection methods using machine learning and deep learning models from videos and pictures have been an interesting topic for researchers. In this paper, a deep learning framework, in which CNN and Transformer models are combined, that classifies emotions using facial and body features extracted from videos is proposed. Facial and body features were extracted using OpenPose, and in the data preprocessing stage 2 operations such as new video creation and frame selection were tried. The experiments were conducted on two datasets, FABO and CK+. Our framework outperformed similar deep learning models with 99% classification accuracy for the FABO dataset, and showed remarkable performance over 90% accuracy for most versions of the framework for both the FABO and CK+ dataset. © 2022 IEEE
Çevrimiçi İkinci El Sektöründe Satıcı-tüketici Özelliklerinin Satıcı-tüketiciye Olan Sadakate Olan Etkisi
No full textThe purpose of this thesis is to contribute to the theory of loyalty which is actively researched in marketing literature and to contribute to the concept of online second-hand consumption by examining the loyalty concept in the online second-hand consumption context. With this intention, a netnographic study and in-depth interviews were conducted to investigate the factors related to the seller-consumer and the relationship of these factors with loyalty, and then a survey study was conducted to test the findings. In addition, the factors related to the seller-consumer in online second-hand shopping were examined under sub-headings. Behavioral variables related to consumers and seller-consumers in online second-hand shopping were discussed. In the thesis, the effect of the variables existing in the online second-hand shopping environment and their relationship with the loyalty of the seller-consumer have been studied. For this purpose, over a period of more than one year, the seller-consumer profiles and the interaction between the consumer and the seller-consumer were examined in five different second-hand shopping platforms, in different periods. After this netnographic observation, semi-structured in-depth interviews were conducted with nine people to better understand the subject. These participants were selected among individuals who have the role of consumer and seller-consumer in online second-hand shopping. Then, a survey was conducted with 322 participants, most of whom were between the ages of 22-28, to determine the relationship between the variables obtained. Then, the reliability tests of the data were carried out in the AMOS program, and the factors leading to seller-consumer loyalty were tested with the structural equation model. As a result of the analysis, it was understood that the interaction between the consumer and the seller-consumer has a direct positive effect on the loyalty of the seller-consumer. In addition, it has been observed that the characteristic features of the product increase the interaction between the consumer and the seller-consumer. In addition, the results show that characteristic features such as the profile photo of the seller-consumer and the number of followers is effective on loyalty. As a result of these results, recommendations were given for future research, and guidance was given to the seller-consumers and intermediary platforms in order to further develop the second-hand shopping sector.Bu tez kapsamında, pazarlama literatüründe aktif olarak araştırılan sadakat kavramını çevrimiçi ikinci el alışveriş sektöründe inceleyerek sadakat kavramına ve çevrimiçi ikinci el alışveriş bağlamına katkıda bulunmak amaçlanmıştır. Tezin amacı çevrimiçi ikinci el kıyafet sektörü üzerinde ürün, satıcı-tüketici ve satıcı-tüketici ile tüketici arasında gerçekleşen etkileşime ilişkin karakteristik özelliklerin, tüketici sadakatine olan etkisini ortaya koymaktır. Bu niyetle, satıcı-tüketiciye ilişkin faktörler ve bu faktörlerin sadakat ile olan ilişkisini araştırmak için netnografik çalışma ve derinlemesine mülakatlar gerçekleştirilmiş, ardından bulgular test edilmek üzere anket çalışması yürütülmüştür. Ayrıca, çevrimiçi ikinci el alışverişte satıcı-tüketiciye ilişkin faktörler alt başlıklar halinde incelenmiş ve çevrimiçi ikinci el alışverişte tüketiciler ile satıcı tüketicilere ilişkin davranışsal değişkenlere değinilmiştir. Tezde çevrimiçi ikinci el alışveriş ortamında var olan değişkenlerin satıcı-tüketiciye olan sadakate etkisi üzerine çalışılmıştır. Bu amaçla bir yılı aşan bir süre zarfında beş farklı ikinci el alışveriş platformunda, farklı zaman dilimlerinde satıcı-tüketici profilleri ve tüketici ile satıcı-tüketici arasında gerçekleşen etkileşim incelenmiştir. Yapılan bu netnografik gözlemin ardından konuyu daha iyi anlamak üzere dokuz kişi ile yarı yapılandırılmış derinlemesine mülakatlar gerçekleştirilmiştir. Bu katılımcılar çevrimiçi ikinci el alışverişte tüketici ve satıcı-tüketici rolüne sahip olan bireyler arasından seçilmiştir. Ardından, elde edilen değişkenlerin arasındaki ilişkiyi belirlemek üzere çoğunluğu 22-28 yaşları arasında olan 322 katılımcı ile anket çalışması gerçekleştirilmiştir. Ardından verilerin AMOS programında güvenilirlik testleri gerçekleştirilerek satıcı-tüketici sadakatine yol açan faktörler yapısal eşitlik modeli ile test edilmiştir. Yapılan analizler sonucunda tüketici ve satıcı-tüketici arasında gerçekleşen etkileşimin satıcı-tüketiciye olan sadakate direkt pozitif etkisi olduğu anlaşılmıştır. Ayrıca ürün ile ilgili karakteristik özelliklerin, tüketici ve satıcı tüketici arasında gerçekleşen etkileşimi arttırdığı gözlemlenmiştir. Ayrıca, sonuçlar satıcı-tüketiciye ait profil resmi, takipçi sayısı gibi karakteristik özelliklerin sadakat üzerinde etkili olduğunu göstermektedir. Bu sonuçlar neticesinde gelecek araştırmalara tavsiyeler verilmiş ve ikinci el alışveriş sektörünü geliştirmek üzere satıcı-tüketiciler ile aracı platformlara yol gösterilmiştir
The Determinants of Defense Spending in the Gulf Region
No full textWe examine the determinants of military spending of the six countries in the Gulf Region by using a partial adjustment model in a system setting estimated with the three-stage least squares (3SLS) method. Our model takes into consideration the institutional inertia as well as intercountry correlations, both observed and unobserved. In addition to economic variables, we also consider a series of strategic variables to shed light on various issues such as free riding and spill-in effects. Our findings based on annual data between 1980 and 2016 indicate that the military expenditures are influenced by both economic and strategic factors with a high degree of heterogeneity across different countries. Our results also show that the GCC member countries do not free ride on each others' military expenditures. In addition, the US military presence is an important determinant of defense spending in the region.Economic Research Forum (ERF)This work was sponsored by the Economic Research Forum (ERF) and has benefited from both financial and intellectual support. The contents and recommendations do not necessarily reflect the ERF's views. We are grateful for the anonymous reviewers for their extremely useful comments and suggestions
Low-Dose Low-Molecular Heparin Prophylaxis Against Obstetrical Complications in Pregnancies With Metabolic and Immunological Disorder-Associated Placental Inflammation
No full textObjective: We investigated the importance of prophylactic administration of low-dose low-molecular-weight heparin (LMWH) in women with risk factors associated with placental inflammation. Materials and methods: This retrospective cohort study included 300 pregnant women with a singleton pregnancy (30 primigravidas and 270 multigravidas) who received prophylactic low-dose LMWH to prevent placental inflammation. Based on maternal risk factors, patients were categorized into 3 groups as follows: Group 1: Patients with metabolic risk factors for placental inflammation (n = 205), Group 2: Patients with immunological risk factors for placental inflammation (n = 42), Group 3: Patients with metabolic and immunological risk factors for placental inflammation (n = 53). Obstetric histories, demographic features, clinical characteristics, and present pregnancy outcomes were compared between groups. Live birth rates, composite adverse obstetric outcomes, and the Beksac obstetric index were compared between present and previous pregnancies in multigravidas. Results: Pregnancy outcomes were significantly better in the present pregnancy than in previous pregnancies. A significant increase was observed in live birth rates (33.4% vs. 69.9%, 27.5% vs. 60.5%, and 30.1% vs. 69.4% in groups 1, 2, and 3, respectively) and in the Beksac obstetric index (0.32 vs. 0.43, 0.33 vs. 0.47, and 0.38 vs. 0.57 in groups 1, 2, and 3 respectively) (p .001 for all). A significant decrease in composite adverse pregnancy outcome rates was observed during the present pregnancy (23.5% vs. 100%, 28.9% vs. 100%, and 24.5% vs. 100% in groups 1, 2, and 3, respectively) (p .001 for all). Live birth and composite adverse obstetric outcome rates were 70% and 33.3%, respectively in primigravidas. Conclusion: Low-dose low-molecular-weight heparin prophylaxis is useful to prevent metabolic and immunological disorders causing placental inflammation, which is the most likely pathophysiological mechanism contributing to various obstetrical complications
Nonlinear Modeling and Robust Backstepping Control of a Quadrotor Unmanned Aerial Vehicle
No full text5th IEEE International Conference on Computer and Informatics Engineering, IC2IE 2022 -- 13 September 2022 through 14 September 2022 -- 184967Developments in information technology have enabled unmanned aerial vehicles to decrease in size, increase their maneuverability and gain vertical landing and take-off features. In this research, a nonlinear model of a quadrotor unmanned aerial vehicle was created using the MATLAB/Simulink program. A robust backstepping controller is designed to provide altitude and attitude control for this model. In order to prove the superiority of the backstepping controller, the results obtained with the classical Proportional Integral Derivative (PID) controller are compared with the performance of the backstepping controller. The rise time, overshoot and settling time values of the PID controller and the backstepping controller were compared. The results showed that the backstepping controller performed more successfully in controlling altitude and attitude angles. © 2022 IEEE
A Modification of Approximate Random Characteristics for A Model of Zika Virus Transmission
No full textIn this study, a theoretical model of Zika virus transmission is investigated with ran-dom parameters. The parameters of a deterministic model are transformed to ran-dom variables to obtain a system of random differential equations. The approximate solutions of the model are analyzed with modified random differential transformation method. It is seen that modified random differential transformation method performs better than random differential transformation method on long time intervals.Research Fund of the Recep Tayyip Erdogan University [FBA-2019-992]This work was supported by Research Fund of the Recep Tayyip Erdogan University. Project No. FBA-2019-992