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Conference Object Citation - WoS: 4Citation - Scopus: 6A Reinforcement Learning Algorithm for Data Collection in Uav-Aided Iot Networks With Uncertain Time Windows(Ieee, 2021) Cicek, Cihan TugrulUnmanned aerial vehicles (UAVs) have been considered as an efficient solution to collect data from ground sensor nodes in Internet-of-Things (IoT) networks due to their several advantages such as flexibility, quick deployment and maneuverability. Studies on this subject have been mainly focused on problems where limited UAV battery is introduced as a tight constraint that shortens the mission time in the models, which significantly undervalues the UAV potential. Moreover, the sensors in the network are typically assumed to have deterministic working times during which the data is uploaded. In this study, we revisit the UAV trajectory planning problem with a different approach and revise the battery constraint by allowing UAVs to swap their batteries at fixed stations and continue their data collection task, hence, the planning horizon can be extended. In particular, we develop a discrete time Markov process (DTMP) in which the UAV trajectory and battery swapping times are jointly determined to minimize the total data loss in the network, where the sensors have uncertain time windows for uploading. Due to the so-called curse-of-dimensionality, we propose a reinforcement learning (RL) algorithm in which the UAV is trained as an agent to explore the network. The computational study shows that our proposed algorithm outperforms two benchmark approaches and achieves significant reduction in data loss.Conference Object Microstrip Antennas For WiMAX Applications(Ieee, 2015) Demirci, Tugkan; Caliskan, Fatma; Aydin, ElifIn this paper, four different antenna types have been designed to be used for WiMAX applications. These antennas have been designed using HFSS simulation software. This paper has included the return loss and the radiation pattern of the designed antennas. Using the simulation results, it is shown that these four antennas are working on Wi-Fi and WiMAX frequency ranges.Conference Object Citation - WoS: 4A Layered Security Architecture for Corporate 802.11 Wireless Networks(Ieee, 2004) Erten, YM; Tomur, EIn this study we have investigated the security aspects of wireless local area networks and discussed the weaknesses associated with various conventional 802.11 security protocols such as WEP and 802.1x. We propose an architecture to control access to corporate 802.11 wireless networks, based on the privileges and location of users, using the tested wired network components such as VPNs and Firewalls. The presented architecture reduces the security risks in enterprise level deployment of wireless LANs.Conference Object Citation - WoS: 16Citation - Scopus: 30A Search-Based Approach for Cost-Effective Software Test Automation Decision Support and an Industrial Case Study(Ieee, 2014) Amannejad, Yasaman; Garousi, Vahid; Irving, Rob; Sahaf, ZahraTest automation is a widely-used approach to reduce the cost of manual software testing. However, if it is not planned or conducted properly, automated testing would not necessarily be more cost effective than manual testing. Deciding what parts of a given System Under Test (SUT) should be tested in an automated fashion and what parts should remain manual is a frequently-asked and challenging question for practitioner testers. In this study, we propose a search-based approach for deciding what parts of a given SUT should be tested automatically to gain the highest Return On Investment (ROI). This work is the first systematic approach for this problem, and significance of our approach is that it considers automation in the entire testing process (i.e., from test-case design, to test scripting, to test execution, and test result evaluation). The proposed approach has been applied in an industrial setting in the context of a software product used in the oil and gas industry in Canada. Among the results of the case study is that, when planned and conducted properly using our decision-support approach, test automation provides the highest ROI. In this study, we show that if automation decision is taken effectively, test-case design, test execution, and test evaluation can result in about 307%, 675%, and 41% ROI in 10 rounds of using automated test suites.Conference Object A Bayes decision model for RSS based location estimation(Ieee, 2007) Dincer, Zeynep; Oektem, Rwen; Aydin, ElifThis work introduces a location estimation method based on Bayes Decision Theory using Radio Signal Strengths for indoor environment. Signal Strengths are observed through three transmitters at three distinct frequencies in UHF band, an active RFID tag and a modem connected to a computer. The test environment is 2100cmx720cm, which is divided into classed of square grids. For each class, a set of received signal strengths are measured and processed. Assuming that the class in which the RFID tag was located in the previous time of measurement is known, the next location (class) is estimated using Bayes Decision Theory. Proposed method is tested in a laboratory environment with obstacles. Results show that proposed method will be successful in location estimation where the estimation error stays within around 2m.Conference Object Multiple Underwater Target Bearing Tracking Using Member Filter(Ieee, 2018) Gunes, Ahmet; Guldogan, Mehmet B.Underwater acoustic vector sensors (AVS) are devices which can measure scalar pressure and three dimensional acceleration or particle velocity with only one sensor. By using these four measurements, target detection and tracking is possible. In case multiple targets exist, multi-target detection and tracking methods must be applied. Because these methods are more general, the algorithms are more involved and complex. In this framework, multi-target multi-Bernoulli (MeMBer) is a promising filter based on random finite sets (RFS) for multi-target tracking problems. In this work, for the first time in the literature, MeMBer filter is analyzed using a single underwater acoustic vector sensor in a scenario including two targets. Simulation results indicate that MeMBer filter can successfully track the targets.Conference Object Design and Implementation of an Expressive Talking Mobile Robot: Toztorus(Ieee, 2018) Tozan, Ozalp; Tora, Hakan; Uslu, Baran; Unal, Bulcnt; Ceylan, EceThis paper is about a brand new robot and all its development stages from the design to the show time. As an undergraduate research project (the LAP program at Atilim University), the robot TozTorUs is the outcome of the dense efforts of a team. With the sensors equipped, it navigates autonomously in the environment in which it is located by avoiding the obstacles. It can understand your questions and answer them using Google's speech technologies. Although it is not a humanoid robot, with eyes and mouth simulator LED displays, it is as friendly as a human. We can also control TozTorUs using a mobile phone. Apart from these, it is able to adjust its height with respect to the visitor's, thus allowing it to make an eye contact with the person. Although TozTorUs is designed for welcoming, it may also be employed for consulting, security and elderly assistance.Conference Object Citation - WoS: 1Characterization of Satellite Transponder Impairments Based on Simulations with Test Data(Ieee, 2015) Ulubey, Orhan; Gulgonul, Senol; Kara, AliA satellite transponder simulator based on actual test data of TURKSAT 3A satellite has been developed to analyze degradation in multicarrier scenarios. Communication impairment sources through a transponder are explained in conjunction with a methodology defined to characterize total degradation resulting from them. Several transponder utilization scenarios are studied with respect to total degradation and optimum operation conditions are demonstrated.Conference Object Citation - WoS: 7Citation - Scopus: 8Formation Control of a Multi-Agent System Using Decentralized Nonlinear Servomechanism(Ieee, 2003) Gazi, VIn this article we consider the formation control problem of a system of M agents with general nonlinear dynamics. We show that the problem of the agents moving in a formation along constant or periodic trajectories can be formulated as a nonlinear output regulation (servomechanism) problem and solved using known techniques. Then, we consider the example of formation control of agents with point mass dynamics and apply the procedure. Few illustrative numerical simulation examples are also provided.Conference Object Citation - WoS: 13Citation - Scopus: 34Swarm Aggregations Using Artificial Potentials and Sliding Mode Control(Ieee, 2003) Gazi, VIn this article we build on our earlier results in [1, 2] on swarm stability. In [1, 2] we had considered aggregating swarm model in n-dimensional space based on artificial potential functions for inter-individual interactions and motion along the negative gradient of the combined potential. Here we consider a general model for vehicle dynamics of each agent (swarm member) and use sliding mode control theory to force their motion to obey the dynamics of the swarm considered in [1, 2]. In this context, the results in [1, 2] serve as a "proof of concept" for swarm aggregation, whereas the present results serve as possible implementation method for engineering swarms with given vehicle dynamics. Moreover, the presented control scheme is robust with respect to disturbances and system uncertainties.
