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Conference Object Driving Conditions Leading To Thermal Runaway in Li-Ion Battery EV's(IEEE, 2024) Ertan, H. Bulent; Azuaje-Berbeci, Bernardo J.The adoption of high-energy-density lithium-ion batteries (LIB) as the energy source in electric vehicles (EV) introduces significant safety concerns. Thermal runaway (TR), a self-accelerating rise in battery temperature resulting in catastrophic failure, is a significant safety concern. Cooling system failure within the EV's thermal management system is one of several factors that can trigger TR. Typically, TR is initiated by exceeding a critical temperature threshold under abusive conditions. Understanding the operating conditions that lead to the path of TR is essential for ensuring EV and occupant safety. Recently, a detailed electrochemical-thermal model that incorporates the chemical reactions within the battery until TR is introduced. This paper aims to illustrate how this model can be used to identify the conditions leading to TR under realistic EV driving scenarios. For this purpose, an Advisor/Matlab-based model of a hybrid EV is developed and verified by tests, is used to estimate the current required from the vehicle's battery pack at a given driving condition. This is followed by the prediction of battery thermal response using the mentioned finite-element-analysis-based battery model. Several scenarios are tested in this paper to determine whether TR occurs and to identify the factors contributing to TR. This study aids in comprehending the factors that contribute to TR and the development of preventative measures for battery management system design.Article Developing a Data Warehouse for Distance Remote Laboratory(IEEE, 2007) Türkmen, Güzin; Çağıltay, NergizData warehouse is an important contemporary issue for many organizations and is relatively a new field in the realm of information technology. As data warehousing, e learning is also a new field. Little research has been done regarding the special considerations and characteristics of academic data and the complexity of analyzing such data. Educational institutions measure success very differently from business-oriented organizations and the analyses that are meaningful in such environments cause unique problems in data warehousing. Especially for the educational purposes, data warehouses offer several benefits. This paper discusses the use of Data Warehouse and Decision Support resources to aid in the assessment of Distance Remote Laboratory Environment.Article Using Learning Style Theory in Remote Laboratory Applications(IEEE, 2007) Tokdemir, Gül; Çağıltay, NergizStudies have shown that, while learning different concepts, people sometimes use different approaches. These different approaches define individual learning styles. Understanding learning style differences is thus an important step in improving performance of the individuals and educational institutions. In this study, a learning style assessment tool was used to examine the relationship between students’ learning styles and their performance in engineering education programs of Atilim University. 329 students (55 female) participated in this study. At their first year in the program, students’ learning styles are measured by a learning style assessment tool developed by David Kolb. The results show that, at the Atilim University’s engineering education program, most of the students are having assimilator type of learning style (45%). Convergers (27%) and divergers (22%) follow the assimilators. The number of accommodators is very limited (5%). This information can be used to create adaptive teaching environments in distance education courses.Article Distance Laboratory Applications ERRL: A Study on Radio Communication in Electronic Field(IEEE, 2008) Aydın, Cansu Çiğdem; Özyurt, E.; Aydın, Elif; Çağıltay, Nergiz; Özbek, Mehmet Efe; Alparslan, Ceren; Kara, AliIn the last decade, the effect of internet usage in education is gradually increased. When we look from academic perspective, the new technologies provided alternatives for students learning. As distance education becomes important everyday, the indispensable elements of teaching and education, laboratories must be reachable via remote connection. Consequently, the education that is going to be given to the students will be more flexible with respect to place and time constraints and students can reach laboratory facilities at any time and anywhere not only in lectures and practical hours. In this study, European Remote Radio Laboratory (ERRL) which is a distance remote Radio Frequency (RF) laboratory designed for electrical-electronics students, is described generally. The software architecture, infrastructure and experiment that can be done with a remote connection have been described.Article Use of Advanced Technologies in a Rf and Microwave Engineering Course(IEEE, 2010) Aydın, Elif; Çağıltay, NergizIn RF and Microwave Engineering course, usually students struggle to build connections between the theory they have learned and practical applications in the laboratory. The laboratory applications are usually very limited for hands on experience since the high cost and maintenance requirements of the equipment. Additionally, new engineers need to know how to use at least one engineering design tool in order to practice designing RF components, circuits, or antennas. In this study, a curriculum model including recent developments and technologies in the RF and Microwave Engineering field by addressing above problems of the course is proposed. This study covers the description of the content of theoretical and hands on applications, the integration model of the technological tools into the proposed curriculum, and the instructional approaches used in the new course design which covers the use of a remote laboratory environment, Concept Maps and an engineering design tool. The course is structured with a balance between theory and laboratory, including remote and in lab measurement experiments as well as modeling and designing microwave components by means of computer tools and design fabrication. The newly designed course is implemented at the Atilim University. The first semester implementation shows promising results.Article How To Teach Usage of Equipments in a Remote Laboratory(IEEE, 2007) Alparslan, Nimet Ceren; Çağıltay, Nergiz; Özen, Mustafa; Aydın, ElifEuropean Remote Radio Laboratory (ERRL) is an e learning project for students, teachers and technicians of the universities who will use the very important devices of this laboratory remotely. These devices are very expensive to buy and can be broken easily while they have been using by the people who does not really know how to use them professionally. As a solution we have developed an e-learning system which aims to support the ERRL learners while studying on how to use equipments in the system. The system is developed according to the electronic performance support systems (EPSS) approach. An EPSS is a computer-based, well structured system which improves the performance of individuals. It is an electronic infrastructure that contains, stores and distributes personal (individual) or corporate knowledge to enable people to reach necessary levels of performance in the fastest possible time and with minimum teaching support of other people. This paper discusses how the content for such a system is developed and how this content is interactively used in the EPSS platform. The technical details of the developed EPSS are also discussed in this study. We believe that this paper will help instructional system designers for designing different alternatives to improve learners’ performance.Conference Object How To Teach Usage of Equipments in a Remote Laboratory(IEEE, 2007) Alparslan, N. Ceren; Cagiltay, Nergiz Ercil; Ozen, Mustafa; Aydin, ElifEuropean Remote Radio Laboratory (ERRL) is an e-learning project for students, teachers and technicians of the universities who will use the very important devices of this laboratory remotely. These devices are very expensive to buy and can be broken easily while they have been using by the people who does not really know how to use them professionally. As a solution we have developed an e-leaming system which aims to support the ERRL learners while studying on how to use equipments in the system. The system is developed according to the electronic performance support systems (EPSS) approach. An EPSS is a computer-based, well-structured system which improves the performance of individuals. It is an electronic infrastructure that contains, stores and distributes personal (individual) or corporate knowledge to enable people to reach necessary levels of performance in the fastest possible time and with minimum teaching support of other people. This paper discusses how the content for such a system is developed and how this content is interactively used in the EPSS platform. The technical details of the developed EPSS are also discussed in this study. We believe that this paper will help instructional system designers for designing different alternatives to improve learners' performance.Conference Object Model Enhancement for UAV Stealth in X-Band(IEEE, 2025) Unalir, Dizdar; Yalcinkaya, Bengisu; Aydin, ElifWith the rapid advancement of technology, radar detection techniques continue to evolve, challenging the effectiveness of traditional unmanned aerial vehicles (UAVs) stealth techniques. As the usage of UAVs in military applications expands, the need for effective radar cross section reduction (RCSR) methods to enhance their stealth capabilities has grown significantly. In this study, we propose an enhancement of a previously developed Low-RCS UAV model, focusing on RCSR with shaping technique in the X-band. For the identification and optimization of the UAV model's highly reflective components, a detailed simulative analysis of the RCS was performed using CST Studio Suite Environment. The modifications are applied to the body and leg components to minimize radar reflections. Simulation results demonstrated that the proposed enhancements significantly reduced RCS values compared to the original Low-RCS UAV model. A total of 13 dBsm reduction in RCS was observed compared to the traditional UAV models. Comparative analysis for different frequencies in X-Band and various aspect angles confirmed the effectiveness of the improved design, validating its potential for stealth applications. The findings can contribute to the research in UAV stealth technology and provide insights into future low-visibility UAV designs.Article How Assessment System of an Open Source Learning Management System Can Be Integrated To a Remote Laboratory Application? Problems and Solutions(IEEE, 2007) Aydın, Cansu Çiğdem; Çağıltay, NergizMost of the education programs need an assessment system for formative and summative evaluation purposes. Similarly, in the ERRL* project which is a distance remote radio frequency laboratory application, assessment system is required. However, developing an assessment system cost is very high and requires some extra time for testing and development purposes. Open source systems provide these services in a standard way. Since the source is open, it is possible to make some modifications to better adapt these systems to the requirements of developed systems. Similarly, in the Moodle part of the system we need to integrate the test and the experiment platforms. In order to better guide the learners in the system, they should take some tests about the devices and the theoretical content included in the system. It is important to prevent users who do not have the enough knowledge directed to the experiments platform. These testing requirements should be integrated into the remote laboratory system, so that, the learners should not need to jump between different systems and interfaces. This article presents implementation process of open source Learning Management System software’s assessment module to a remote laboratory application and it also discusses the advantages, disadvantages of using an open source Web based assessment system.Conference Object Citation - WoS: 2Citation - Scopus: 2Radar Cross Section Studies of Low Signature UAVs in X-Band: Simulation, Measurement and Performance Evaluation(IEEE, 2024) Unalir, Dizdar; Gokdogan, Bengisu Yalcinkaya; Aydin, ElifIn this study, the effectiveness of a radar cross section (RCS) reduction method based on a proposed shaping technique for four-legged unmanned aerial vehicles (UAV) has been proven with simulation tools and experimental measurements in X-Band. Simulative RCS values were obtained with CST and HFSS electromagnetic calculation tools, and the advantages of these tools compared to each other were examined. Experimental measurements were carried out in a laboratory environment with a vector network analyzer (VNA) and confirmed with simulation results. The effects of frequency, polarization and aspect angle factors on RCS were examined. It has been shown that with the proposed measurement method, low-cost and easily applicable RCS analysis can be performed in X-Band, one of the frequency bands frequently used in the defense industry. With the proposed shaping method, RCS reduction in the range of 5-10 dBsm was achieved.
