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Publication Metadata only Operator User Management System Based on the TMF615 Standard(SPRINGER, 2016) Yigit, Melike; Macit, Muhammed; Gungor, V. Cagri; Kocak, Taskin; Ozhan, Oguz; Bahcesehir University; Abdullah Gul University; Alcatel Lucent Teletas Turkey; Alcatel-LucentMulti-vendor telecommunications networks in a typical service provider environment are managed using multiple proprietary user management systems (UMS), supplied by the operational support system (OSS) vendors. The management of a typical service provider includes communications solutions put into place between the global UMS and the local UMS. Nowadays, in service provider environments OSSs exist that use multi-vendor communications' protocols. In the telecommunications sector, the centralized management of all these different OSSs can cause serious problems for the network operation. In this respect, there is an urgent need for a standardized and centralized provisioning and auditing mechanism for the operators and their entitlements that work on these management systems. To address this need and to provide efficient operations among different service provider network components, this paper outlines the design and development of a TMF615 (Tele Management Forum) standard-based, common communication platform. In this respect, the proposed approach includes a common interface to address communication problems in multi-vendor, service provider environments. The interface and performance evaluations developed are some of the first solutions in this field, and the resulting solutions are converted into a commercial product with a high added value. In this regard, our proposed approach makes an important contribution to scientific literature and commercial applications. The realization of the proposed TMF615 standard-based interface enables the efficient and easy integration of existing and new OSSs of the service providers. In this way, a standardized interface is offered, along with a common communications platform adequate for all different systems. The vendors are thereby only responsible for application development based on specifications, and a standardized communications process is introduced for all related systems. This significantly facilitates the management of service providers, system performance is improved, and a massive cost reduction is provided at the same time. Consequently, the efficient management of network components is provided using a common standardized interface. In this respect, we aim to explain the TMF615 specifications, the evolution of UMS, OSSs and TMF615 with centralized UMS, as well as the implementation and performance evaluation of the TMF615 protocol are all explained in this paper.Publication Metadata only Routing protocol design guidelines for smart grid environments(ELSEVIER, 2014) Temel, Samil; Gungor, Vehbi Cagri; Kocak, Taskin; Turkish Air Force; Turkish Air Force Academy; Abdullah Gul University; Bahcesehir UniversityThe evaluation of the current electric power grid with novel communication facilities is one of the most challenging and exciting issues of the 21st century. The modern grid technology is called the smart grid in the sense that it utilizes digital communication technologies to monitor and control the grid environments, which ultimately require novel communication techniques to be adapted to the system. Wireless sensor networks (WSN) have. recently been considered as a cost-effective technology for the realization of reliable remote monitoring systems for smart grid. However, problems such as noise, interference and fading in smart grid environments, make reliable and energy-efficient multi-hop routing a difficult task for WSNs in smart grid. Our main goal is to describe advantages and applications of WSNs for smart grid and motivate the research community to further investigate this promising research area. In this study we have investigated and experimented some of the well-known on-demand, table-driven and QoS-aware routing protocols, in terms of packet delivery ratio, end-to-end delay, and energy consumption to show the advantages and disadvantages of each routing protocol type in different smart grid spectrum environments. The environmental characteristics which are based on real-world field tests are injected into ns-2 Network Simulator and the performance of four different multi-hop routing protocols is investigated. Also, we have shown that traditional multi-hop routing protocols cannot deliver adequate performance on smart grid environments. Hence, based on our simulation results, we present some guidelines on how to design routing protocols specifically for smart grid environments. (C) 2013 Elsevier B.V. All rights reserved.Publication Metadata only From Asia to Europe: Short-Term Traffic Flow Prediction Between Continents(IEEE, 2014) Kaya, Sevgi; Kilic, Necati; Kocak, Taskin; Gungor, Cagri; Swiss Federal Institutes of Technology Domain; ETH Zurich; Bahcesehir UniversityModelling the traffic flow and predicting the near-future traffic status are two challenging problems of the smart transportation on roads. The difficulty is particularly pronounced in forecasting the complex non-linear dynamics of flow. Most of the state-of-the-art work on traffic flow prediction determine the parameters based on the fundamental relationship between flow, density and speed without considering its influence to the consecutive one. However, these approaches tend to fail in real life scenarios due to the negligence of the spatio-temporal dependence of parameters within road segments. In this paper, we propose a new traffic flow model to predict the arterial travel time using probe data. We then evaluate our model under various traffic conditions to determine its feasibility for near-future traffic flow prediction. The proposed method presents promising results by outperforming the state-of-the-art in predicting near-future traffic flow on roads in case of sparse data and high flow density.Publication Metadata only Low-complexity high-throughput decoding architecture for convolutional codes(SPRINGER, 2012) Xu, Ran; Morris, Kevin; Woodward, Graeme; Kocak, Taskin; University of Bristol; Bahcesehir UniversitySequential decoding can achieve a very low computational complexity and short decoding delay when the signal-to-noise ratio (SNR) is relatively high. In this article, a low-complexity high-throughput decoding architecture based on a sequential decoding algorithm is proposed for convolutional codes. Parallel Fano decoders are scheduled to the codewords in parallel input buffers according to buffer occupancy, so that the processing capabilities of the Fano decoders can be fully utilized, resulting in high decoding throughput. A discrete time Markov chain (DTMC) model is proposed to analyze the decoding architecture. The relationship between the input data rate, the clock speed of the decoder and the input buffer size can be easily established via the DTMC model. Different scheduling schemes and decoding modes are proposed and compared. The novel high-throughput decoding architecture is shown to incur 3-10% of the computational complexity of Viterbi decoding at a relatively high SNR.Publication Metadata only High Throughput Parallel Fano Decoding(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2011) Xu, Ran; Kocak, Taskin; Woodward, Graeme; Morris, Kevin; Dolwin, Craig; University of Bristol; Bahcesehir University; Toshiba CorporationIn this paper, a bidirectional Fano algorithm (BFA) is proposed, in which a forward decoder (FD) and a backward decoder (BD) search in the opposite direction in the code tree simultaneously. It is shown that the proposed BFA can achieve more than twice the decoding throughput compared to the conventional unidirectional Fano algorithm (UFA) and there is higher throughput improvement at low signal-to-noise ratio (SNR). This new BFA decoding technique is applied in the parallel convolutional decoding architecture in very high throughput systems, such as the WirelessHD system. Due to the variability in the decoding delays of the parallel codewords, a scheduler is introduced in the parallel Fano decoding architecture which can dynamically allocate the idle decoders to assist with decoding the other parallel codewords in a bidirectional manner. It is shown that the proposed parallel Fano decoding with scheduling can dramatically increase the decoding throughput compared to the parallel Fano decoding without scheduling, and its computational complexity is much lower than that of parallel Viterbi decoding, especially at high SNR. The performance of the parallel Fano decoding with different scheduling schemes is also compared and analyzed in detail in the paper.Publication Metadata only Quality-of-service differentiation in single-path and multi-path routing for wireless sensor network-based smart grid applications(ELSEVIER, 2014) Sahin, Dilan; Gungor, Vehbi Cagri; Kocak, Taskin; Tuna, Gurkan; Bahcesehir University; Abdullah Gul University; Trakya UniversityElectrical grid is one of the most important infrastructure of the modern nation. However, power grid has been aged over 100 years and prone to major failures. The imbalance between power demand and supply, the equipment failures and the lack of comprehensive monitoring and control capabilities are other important signs to take incremental steps for switching to a smarter power grid with effective communication, automation and monitoring skills. This new concept is named as smart grid, which is a modern power grid system with advanced communication, monitoring, sensing and control capabilities. Wireless sensor network (WSN) concept places an important role in this modernization process of the power grid with its efficient and low-cost deployment characteristics. However, harsh and complex smart grid environmental conditions, dynamic topology changes, connectivity problems, interference and fading may pose some challenges for the communication performance of WSN technology. For this objective, in this paper, the use of multi-path and single-path QoS-aware routing algorithms under harsh SG environmental conditions is investigated in order to evaluate their service differentiation capabilities in reliability and timeliness domains. In this regard, this study is an important step towards developing novel routing protocols specifically designed for smart grid environments. (C) 2014 Elsevier B.V. All rights reserved.Publication Metadata only Credit Risk Analysis based on Hybrid Classification: Case Studies on German and Turkish Credit Datasets(IEEE, 2018) Cetiner, Erkan; Kocak, Taskin; Gungor, V. Cagri; Bahcesehir University; Abdullah Gul UniversityIn finance sector, credit risk analysis plays a major role in decision process. Banks and finance institutions gather large amounts of raw data from their customers. Data mining techniques can be employed to obtain useful information from this raw data. Several data mining techniques, such as support-vector machines (SVM), neural networks, naive-bayes, have already been used to classify customers. In this paper, we propose hybrid classification approaches, which try to combine several classifiers and ensemble learners to boost accuracy on classification results. Furthermore, we compare these approaches' performance with respect to their classification accuracy. We work with two diverse datasets, namely, German credit dataset and Turkish bank dataset. The goal of using such diverse dataset is to show generalization capabality of our approaches. Experimental results provide three important consequences. First, feature selection stage has a major role both on result accuracy and calculation complexity. Second, hybrid approaches have better generalability over single classifiers. Third, using SVM-Radial Basis Function (RBF) as the base classifier and a hybrid model member gives the best accuracy and type-1 accuracy results among others.Publication Metadata only Location-aided Multi-user Beamforming for 60 GHz WPAN Systems(IEEE, 2012) Han, Congzheng; Zhu, Xiaoyi; Doufexi, Angela; Kocak, Taskin; University of Bristol; Bahcesehir University60 GHz wireless personal area networks (WPANs) offer multi-Gbps throughput, which will provide for a new wave of high data rate applications. This paper exploits the use of location information to improve the performance and enhance range of 60 GHz multi-user beamforming systems. When the location information is available at the transmitter, the scheduler chooses a set of maximum angularly separated users to share wireless resources simultaneously. If additional feedback of signal-to-interference and noise ratio (SINR) is known, a location-assisted scheduler is employed to increase the system overall performance. Both numerical and simulated results show that significant enhancement can be achieved by the proposed schedulers for 60 GHz WPAN systems.Publication Metadata only A Performance Evaluation of 60 GHz MIMO Systems for IEEE 802.11ad WPANs(IEEE, 2011) Zhu, Xiaoyi; Doufexi, Angela; Kocak, Taskin; University of Bristol; Bahcesehir UniversityThe IEEE 802.11ad task group has published its first draft to cope with the characteristics in 60 GHz millimeter-wave (mmWave) wireless communications. In this paper, three different 2x2 multiple-input multiple-output (MIMO) techniques are considered to enhance the performance of 60 GHz wireless personal networks (WPANs). Packet Error Rate (PER) and link throughput performance are simulated under different channel conditions. In addition, the system throughput over operation range is presented in the paper. Results show that significant enhancements in both coverage and capacity can be achieved by employing space-time block codes (STBC), spatial multiplexing (SM) and three different configurations of beamforming.Publication Metadata only GPU-Based FFT Computation for Multi-Gigabit WirelessHD Baseband Processing(SPRINGEROPEN, 2010) Hinitt, Nicholas; Kocak, Taskin; Bahcesehir University; University of BristolThe next generation Graphics Processing Units (GPUs) are being considered for non-graphics applications. Millimeter wave (60 Ghz) wireless networks that are capable of multi-gigabit per second (Gbps) transfer rates require a significant baseband throughput. In this work, we consider the baseband of WirelessHD, a 60 GHz communications system, which can provide a data rate of up to 3.8 Gbps over a short range wireless link. Thus, we explore the feasibility of achieving gigabit baseband throughput using the GPUs. One of the most computationally intensive functions commonly used in baseband communications, the Fast Fourier Transform (FFT) algorithm, is implemented on an NVIDIA GPU using their general-purpose computing platform called the Compute Unified Device Architecture (CUDA). The paper, first, investigates the implementation of an FFT algorithm using the GPU hardware and exploiting the computational capability available. It then outlines the limitations discovered and the methods used to overcome these challenges. Finally a new algorithm to compute FFT is proposed, which reduces interprocessor communication. It is further optimized by improving memory access, enabling the processing rate to exceed 4 Gbps, achieving a processing time of a 512-point FFT in less than 200 ns using a two-GPU solution.