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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 Area efficient System-on-Programmable-Chip Design for a Wireless Touch-Triggered Machining Probe(IEEE, 2011) Mimis, Konstantinos; Kocak, Taskin; University of Bristol; Bahcesehir UniversityIn this paper, we present the design and implementation details of a System-on-Programmable-Chip (SoPC), which replaces the circuitry that controls the operation of a touch-triggered machining probe with radio transmission capability. The probe is used to get precise measurements of three dimensional geometric parts. The goal is to achieve size reduction of an existing circuitry inside the probe, that consists of two microcontrollers and a reconfigurable hardware device such as a Field Programmable Gate Array (FPGA), that implements some custom functions. In order to reduce the printed circuit board (PCB) area occupied by these three chips and the associated routing area, we combine them on a single SoPC. An overall 6 fold reduction in PCB area occupied, corresponding to nearly 15cm(2) is achieved.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 Enhancement for 60 GHz Wireless Indoor Applications(IEEE, 2012) Zhu, Xiaoyi; Doufexi, Angela; Kocak, Taskin; University of Bristol; Bahcesehir UniversityThis paper studies the throughput and range of the OFDM based IEEE 802.11ad millimeter-wave WPANs. The cross layer results show that the MIMO and beamforming schemes with frame aggregation and block acknowledgement enhance the throughput and operation range compared to the case of single antenna with reasonable hardware complexity.Publication Metadata only Design and Implementation of High-Performance High-Valency Ling Adders(IEEE, 2012) Kocak, Taskin; Patil, Preeti; Raik, J; Stopjakova, V; Jenihhin, M; Vierhaus, HT; Pleskacz, W; Ubar, R; Bahcesehir University; University of BristolParallel prefix adders are used for efficient VLSI implementation of binary number additions. Ling architecture offers a faster carry computation stage compared to the conventional parallel prefix adders. Recently, Jackson and Talwar proposed a new method to factorize Ling adders, which helps to reduce the complexity as well as the delay of the adder further. This paper discusses the design and implementation details for such lower complexity, fast parallel prefix adders based on Ling theory of factorization. In particular, valency or radix, the number of inputs to a single node, is explored as a design parameter. Several low and high valency adders are implemented in 65 nm CMOS technology. Experimental results show that the high-valency Ling adders have superior areaxdelay characteristics over previously reported Ling-based or non-Ling adders for the same input size. Moreover, our 20-bit high valency adder has a better areaxdelay measurement than the previously-published 16-bit adders.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 Throughput and Coverage Performance for IEEE 802.11ad Millimeter-Wave WPANs(IEEE, 2011) Zhu, Xiaoyi; Doufexi, Angela; Kocak, Taskin; University of Bristol; Bahcesehir UniversityRecently, the development and requirement for ultra-high data rate wireless communication applications has increased dramatically. The 60 GHz millimeter-wave wireless technology is getting increasing attention, and the IEEE 802.11 Task Group AD is making standardization efforts for multi-gigabit data rate communications on both the physical (PHY) and medium access control (MAC) layers. This paper presents a performance evaluation of the PHY and MAC layers of IEEE 802.11ad. Packet error rate and PHY throughput are presented for different modes, and the theoretical MAC throughput is analyzed for different bit error rates, packet sizes and modes. In addition, 2x2 space-time block coding (STBC) is employed for range extension. The cross layer results show our approach enhance the throughput and coverage compared to the case of single antenna.Publication Metadata only Graphics processing unit based next generation DDoS prevention system(IEEE, 2016) Keskin, Selcuk; Erdogan, Hasan Tugrul; Kocak, Taskin; Bayrak, C; Ozturk, Y; Varol, C; Bahcesehir UniversityPacket filtering is the main component of prevention systems to protect the network system of the devices against attacks. The algorithm allows the packets to access to network after passing some rules. The packets with decisions are written into a connection table that consists of essential network information. In this paper, we design and implement a massively parallel computation approach of Graphics Processing Unit (GPU) that can be used for network connection tracking. The results show that the GPU based connection table tracking algorithms achieve 90,000,000 packets per second (pps) throughput which is 35 times faster than the packet filtering function defined in Linux kernel.Publication Metadata only Open Distributed System to Provide Real-Time Communication Service over Web(IEEE, 2017) Armagan, Ozgur; Guner, Huseyin; Keskin, Selcuk; Kocak, Taskin; Netas; Bahcesehir UniversityNowadays, corporate companies use different applications and service providers to take advantage of services such as instant messaging, e-mail, social networks and company-wide calls. These service providers are demanding higher licensing fees for additional features needed by the institutions. For example, the ability to call landlines as well as in-house calls can greatly increase the costs of the corporate companies. Moreover, there is no application in the market that provides ease of use by collecting all these services under one roof. In this work, a system has been designed to ensure that all these shortcomings are eliminated and landlines can be called. The