Erdem Uçar

Techno-Economic Evaluation of a Hybrid PV—Wind Power Generation System

This article investigates the possibility of providing electricity from solar/wind hybrid systems for a remote location with no electricity connection in the city of Edirne in the westernmost province of Turkey in order to decrease the high cost of utilizing only stand-alone diesel system and to achieve considerable fuel savings. In this study, National Renewable Energy Laboratorys (NREL) HOMER (Hybrid Optimization Model for Electric Renewables) software is used to perform the techno-economic feasibility of such hybrid systems considering both solar data and wind data. Additionally, the contribution of solar and wind on energy production, cost of energy, and total operating hours of diesel generator is examined for the optimal hybrid configurations. Furthermore, fuel savings and reduction in carbon emissions of different hybrid systems are investigated. Finally, suitability of utilizing hybrid solar–wind energy system over stand-alone diesel system is discussed mainly based on different solar global irradiances, wind speed, and diesel price.

Healthcare Systems and Other Applications

This paper presents healthcare systems and their applications namely helping people with dementia navigate their day, empowering the elderly and the cognitively disabled, context awareness in residence for elders, RFID-based nutritional assistance, a computer-based library for the blind, an NLP-based tool for assisting people with autism, making smart clothing smarter, PAS: a wireless-enabled personal assistance system for independent living

Pervasive Computing Approaches to Environmental Sustainability

This issues Works in Progress department lists eight projects with a focus on environmental sustainability. The first three projects explore sensing and pervasive computing techniques for monitoring environmental conditions in outdoor situations. The next four projects use pervasive computing in indoor environments to inform individuals about their energy and resource consumption with the goal of positively influencing their behaviors. The final project aims to develop an energy generation infrastructure that combines multiple types of renewable energy sources.

Effects of using a force feedback haptic augmented simulation on the attitudes of the gifted students towards studying chemical bonds in virtual reality environment

ABSTRACT The aim of this study is to identify the effects of force feedback haptic applications developed in virtual reality environments (VREs), which is an important field of study in computer science and engineering, on gifted students’ attitudes towards chemistry education in learning process. A 3D 6 DOF (Degree of Freedom) haptik device (Phantom Omni™) has been used to develop the algorithm in this study. It can be used to transmit force and motion using a haptic device. Visual C++ was choosen as the software development environment. OpenGL™ and Haptic Device Application Programming Interface have been used for rendering graphics. At the 3D image creation state Wrap 1200™, which is a kind of head-mounted display, has been chosen. The sample of this study consists of 52 students identified as gifted and are attending 6th and 7th grades at the Istanbul Science & Art Center in Istanbul. The experimental group studied chemical bonds using an application developed by using a force feedback haptic device in VRE and the control group studied it by traditional teaching methods. The study reveals that there is a relation between using force feedback haptic applications which are developed in VREs and gifted students’ attitudes towards educational programs.

Analysis of QoE key factors in IPTV systems: Channel switching

The usage of Internet Protocol TV (IPTV) deployments in the consumer electronics market is growing very popularly in recent years. In IPTV systems, Quality of Experience (QoE) is very critical factor for end-user satisfaction. Existing and future IPTV systems will offer a large number of channels to users. The most important factors that affects to QoE in IPTV systems are channel zapping and channel selection problems. Generally, the channel zapping time depends on several parameters like Internet Group Membership Protocol (IGMP) command processing time, network delay time, IPTV consumer device processing delay time, jitter buffer delay time, MPEG decoder time and Conditional Access/Digital Rights Management (CA/DRM) delay time. In this paper, we present an analysis of channel change delay in IPTV systems and we propose a new approach based on channel-based peer selection, called CBPS where the most suitable peer to construct peer-to-peer (P2P) communication will be discovered from a look-up table in the central server.

Call admission control jointly with resource reservation in cellular wireless networks

To efficiently utilize the total resources and to serve mobile users demanding for different types of service, system resource utilization of these services should be considered, and efficient resource management techniques should be developed. In this paper, we propose a new call admission control (CAC) scheme jointly with resource management by considering the two service types: prioritized calls and nonprioritized calls. Proposed scheme limits the new and handoff prioritized and non-prioritized call arrivals according to call-level quality of service (QoS) requirements. By searching algorithm, admission parameters are obtained optimally and required QoS are guaranteed. Due to high priority of the prioritized calls, the admittance of non-prioritized calls into channel is restricted, while prioritized calls are admitted as long as there is sufficient bandwidth. To evaluate the performance of the proposed CAC scheme, we have compared the numerical results from the analytical model with those of New Call Bounding scheme. It is shown that the proposed CAC scheme uses the resources effectively and improves all the upper-bound QoS requirements with respect to the New Call Bounding scheme for prioritized and non-prioritized users.

Call Admission Control Policy for Integration of Voice/Data Traffic in Cellular Mobile Networks

In integrated voice/data cellular mobile networks, the most important consideration is to utilize the resources in an efficient way and maintain the required quality of service (QoS). In this paper, we proposed a new call admission control scheme for improving efficiency of resource utilization. Proposed scheme restricts the new and handoff voice and data calls arrived to system by finding the optimal threshold number of new and handoff voice and data calls allowed in system according to admission criters such as maximum data response time, voice and data blocking and dropping probabilities. From the numerical analysis, we observed that required call-level QoS for both voice and data calls is provided and upper bound of data response time is guaranteed to data calls. Also taking the required minimum bandwith need of voice calls in different values, we evaluated the performance improvements of data calls.

Performance analysis for resource management in integrated cellular/WLAN networks

To utilize the total resources in cellular/WLAN integration for both cellular and WLAN network, their different channel allocation strategies should be considered and efficient resource management techniques are required. In this paper, we proposed a new call admission scheme to utilize the coupled resources effectively. Proposed scheme, by taking the different resource sharing strategies of both network, limits the new, horizontal and vertical handoff voice and data call arrivals together with call-level QoS requirements. In cellular network, all admission parameters are obtained by searching algorithm. In WLAN, due to preemptive priority of voice calls, the access of data calls into channel is restricted while voice calls are admitted as long as there is sufficient bandwidth. From the numerical analysis, it is shown that integrated network uses the resources effectively and provides the all upper bound QoS requirements to voice and data users.

Developing of a learning-based system to assist treatment process of arrhythmia patients

The transformation process of the data kept in data warehouse into usable information for decision support system is very important. In this process, it is necessary to reveal the useful data that can meet the needs of the developed system. For this purpose, the study of data mining should be done on data warehouse. In this article, the phases of developing and applying a learning-based system in order to be used in the treatment process of arrhythmia patients were presented. Firstly, the data collected in the data warehouse was transformed into information through using data mining methods. In the data mining studies, the nearest neighbour algorithm (kNN) which is one of the machine learning algorithms was used. The process of selecting training data among the data stored in database was realized by a specialist through a web-based practice. In the process of composing training data, the evaluation results of the system about learning level were shown to the specialist in an online way. Thus, the generalizing power of the model made up by a classifier on training data was measured. Besides, to determine and filter the noisy data in the data warehouse, the quality of the signal taken from the patient and the evaluations of the specialist were used. In this way, the classifier used was contributed to form a suitable hypothesis on training data. By finding the proper hypothesis, the critical situations of the patient are conveyed to the doctor of the patient by the improved system within seconds. Thus, the patient is provided to be constantly kept under supervision free from location.

Implantable Electronics

This Works in Progress department features three projects that use pervasive computing technologies to monitor or assist patients. In the first project, the researchers are exploring technologies to enable patients to record their brain activity and head movement while sleeping, and to help automate drug-use supervision. The researchers in the second project are adding ultrasound-based distance ranging to the traditional walking stick that the visually impaired use. In the third project, the researchers used RFID tags to monitor patient behaviors and movement patterns and to limit their access in a hospital.