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Publication Metadata only A component procurement planning and product portfolio design problem(Institute of Industrial Engineers cs@iienet.org, 2010) Ağralı, Semra; Geunes, Joseph P.; Rainwater, Chase E.; Ağralı, Semra, Department of Industrial Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Geunes, Joseph P., Herbert Wertheim College of Engineering, Gainesville, United States; Rainwater, Chase E., College of Engineering, Fayetteville, United StatesWe study a multi-period component procurement-planning and product portfolio design problem with product substitutions and multiple customer segments. Each customer segment has a preferred product with a set of acceptable substitutes. Each product has a fixed design cost and profit margin, both of which are time-period-dependent. Moreover, each product is assembled-to-order from a set of components, and inventory is held at the component level. Our aim is to determine a product portfolio, substitution plan, and procurement plan that maximizes profit. We develop a large-scale mixed-integer linear programming formulation, show that the problem is N P-Hard and provide preliminary computational results. © 2014 Elsevier B.V., All rights reserved.Publication Metadata only Sonic logging in deviated wellbores in the presence of a drill collar(Society of Exploration Geophysicists web@seg.org, 2010) Sinha, Bikash K.P.; Ŝimŝek, Ergün; Sinha, Bikash K.P., Schlumberger-Doll Research Center, Cambridge, United States; Ŝimŝek, Ergün, Bahçeşehir Üniversitesi, Istanbul, TurkeyAcquiring sonic logs while drilling is far more challenging than acquiring sonic logs from a wireline tool, notably because of the higher noise level in the drilling environment. The presence of a drill collar in the form of a thick steel pipe motivates a different tool design strategy. In addition, interference of drilling noise with the formation signal requires new processing and inversion algorithms for estimating the formation compressional and shear slownesses. Generally, all wireline sonic tools estimate the formation shear slowness by processing the borehole flexural arrival that is not severely affected by the tool structure. However, to mitigate interference between the drill collar and formation arrivals in the LWD (Logging-While-Drilling) environment, there has been a growing interest in inverting the borehole quadrupole dispersive arrival for the formation shear slowness. Inversion of quadrupole dispersion yields the same formation shear as that from a dipole shear logging tool in an isotropic and transversely-isotropic (TI) formation when the borehole axis is parallel to the TI-symmetry axis. Nevertheless, it is known that in anisotropic formations, we can have three different shear moduli in the three orthogonal planes. It is then necessary to understand which of the three shear moduli or some combination thereof, would be estimated from the inversion of quadrupole sonic data from a LWD tool in deviated boreholes in TI formations. A finite-difference time domain (FDTD) formulation with a perfectly-matched layer (PML) enables analysis of elastic wave propagation in a fluid-filled borehole in an arbitrarily anisotropic formation in the presence of a drill collar. Introduction of a perfectly-matched boundary layer minimizes reflections from the boundary with a limited grid volume. The FDTD formulation yields synthetic waveforms at an array of receivers produced by a monopole, dipole or quadrupole source placed on the borehole axis. Synthetic waveforms are then processed by a modified matrix pencil algorithm to isolate both non-dispersive and dispersive arrivals in the wavetrain. Computational results have been obtained for various modal arrivals generated by either a monopole, dipole, or quadrupole source placed in a fluid-filled borehole. While dipole flexural dispersions provide estimates of shear rigidity in the two orthogonal borehole axial planes, the monopole Stoneley dispersion can be inverted to estimate the shear rigidity in the borehole cross-sectional plane. In contrast, quadrupole waves simultaneously vibrate the formation in the two orthogonal axial planes. Therefore, inversion of low-frequency quadrupole dispersion based on an isotropic model yields a shear modulus that is some combination of the fast and slow shear moduli in the two orthogonal axial planes. © 2020 Elsevier B.V., All rights reserved.Publication Metadata only Augmenting clinical observations with visual features from longitudinal MRI data for improved dementia diagnosis(2010) Ünay, Devrim; Ünay, Devrim, Bahçeşehir Üniversitesi, Istanbul, TurkeyImage-based diagnosis in the medical area often requires qualitative interpretation from the experts, despite the high-resolution of the acquired images. Computation of quantitative measures and comparison of multiple patients using automated medical image analysis tools will help improve the diagnosis and efficiency, especially in the areas such as neurology, where diagnosis from one patient's data has limitations and the prevalence of neurodegenerative diseases is expected to substantially increase in the near future due to the aging population. To this end, this paper presents a novel work on fusing clinical and patient-demographics related observations with visual features computed from brain longitudinal MRI (magnetic resonance imaging) data for improved dementia diagnosis. Experiments with real data showed that augmenting cognitive scores with visual features from a subset of subcortical structures results in more accurate diagnosis. Moreover, subset of structures typically selected are consistent with those (being) investigated in the literature. Copyright 2010 ACM. © 2010 Elsevier B.V., All rights reserved.Publication Metadata only Grid resource discovery over distributed routers(2010) Kocak, Taskin; Lacks, Daniel; Kocak, Taskin, Department of Computer Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Lacks, Daniel, College of Engineering and Computer Science, Orlando, United StatesComputational grids have emerged as a new paradigm for solving large complex problems over the recent years. The problem space and data set are divided into smaller pieces that are processed in parallel over the grid network and reassembled upon completion. Typically, resources are logged into a resource broker that is somewhat aware of all of the participants available on the grid. The resource broker scheme can be a bottleneck because of the amount of computational power and network bandwidth needed to maintain a fresh view of the grid. In this paper, we propose to place the load of managing the network resource discovery on to the network itself: inside of the routers. In the proposed protocol, the routers contain tables for resources similar to routing tables. These resource tables map IP addresses to the available computing resource values, which are provided through a scoring mechanism. Each resource provider is scored based on the attributes they provide such as the number of processors, processor frequency, amount of memory, hard drive space, and the network bandwidth. The resources are discovered on the grid by the protocol's discovery packets, which are encapsulated within the TCP/IP packets. The discovery packet visits the routers and look up in the resource tables until a satisfactory resource is found. The protocol is validated by simulations with five different deployment environments. ©2010 IEEE. © 2010 Elsevier B.V., All rights reserved.Publication Metadata only Predicting the existence of mycobacterium tuberculosis infection by Bayesian Networks and rough sets, Mycobacterium tuberculosis enfeksiyonunun Bayes aǧlari ve yaklaşimli kümeler ile tahmini(2010) Uçar, Tamer; Karahoca, Dilek Yiğit; Karahoca, Adem; Uçar, Tamer, Bahçeşehir Üniversitesi, Istanbul, Turkey; Karahoca, Dilek Yiğit, Bahçeşehir Üniversitesi, Istanbul, Turkey; Karahoca, Adem, Bahçeşehir Üniversitesi, Istanbul, TurkeyA correct diagnosis of tuberculosis can be only stated by applying a medical test to patient's phlegm. The result of this test is obtained after a time period of about 45 days. The purpose of this study is to develop a data mining solution which makes diagnosis of tuberculosis as accurate as possible and helps deciding if it is reasonable to start tuberculosis treatment on suspected patients without waiting the exact medical test results. In this research, we compared the use of Bayesian Networks and Rough Sets to predict the existence of mycobacterium tuberculosis. 503 different patient records having 30 separate input parameters are obtained from a private clinic and used in the entire process of this research. The Bayesian Network model classifies the instances with RMSE of 22% whereas Rough Set algorithm does the same classification with RMSE of 37%. As a result, Bayesian Network is an accurate and reliable method when compared with Rough Set method for classification of tuberculosis patients. ©2010 IEEE. © 2010 Elsevier B.V., All rights reserved.Publication Metadata only Determinig the ligand-specific regions of peptide-binding G-Protein Coupled Receptors(2010) Çobanoǧlu, Murat Can; Sezerman, Osman Uğur; Karabulut, Nermin Pinar; Çobanoǧlu, Murat Can, Faculty of Engineering and Natural Sciences, Sabancı Üniversitesi, Tuzla, Turkey; Sezerman, Osman Uğur, Faculty of Engineering and Natural Sciences, Sabancı Üniversitesi, Tuzla, Turkey; Karabulut, Nermin Pinar, Department of Computer Science, Bahçeşehir Üniversitesi, Istanbul, TurkeyThe G-Protein Coupled Receptor (GPCR) proteins are of paramount importance for pharmaceutical research as this single family of proteins is targeted by more than 50% of all modern drugs. Their ligands include but are not limited to small molecules, peptides and photons. Consequently it is vital to know the sites of interaction between the ligand and the receptor. These sites can be used for a multitude of purposes such as classification of sequences or drug design. We use the feature extraction method proposed in [1] to analyze the ligand-specific regions among various Peptide-binding GPCRs. We present the features that will help drug design researchers enhance specificity of peptide-binding drugs. © 2009 IEEE. © 2010 Elsevier B.V., All rights reserved.Publication Metadata only Authoring and presentation tools for distance learning over interactive TV(2010) Gürel, Turan Can; Erdem, Tanju Tanju; Kermen, Ahmet; Özkan, Mehmet K.; Erdem, Cigdem Eroglu; Gürel, Turan Can, Momentum AS, Kocaeli, Turkey; Erdem, Tanju Tanju, Özyeğin Üniversitesi, Istanbul, Turkey; Kermen, Ahmet, Momentum AS, Kocaeli, Turkey; Özkan, Mehmet K., Momentum AS, Kocaeli, Turkey; Erdem, Cigdem Eroglu, Bahçeşehir Üniversitesi, Istanbul, TurkeyWe present a complete system for distance learning over interactive TV with novel tools for authoring and presentation of lectures and exams, and evaluation of student and system performance. The main technological contributions of the paper include the development of plug-in software so that PowerPoint can be used to prepare presentations for the set-top-box, a software tool to convert PDF documents containing multiple-choice questions into interactive exams, and a virtual teacher whose facial animation is automatically generated from speech. © 2013 Elsevier B.V., All rights reserved.Publication Metadata only Exploiting the power of GPUs for multi-gigabit wireless baseband processing(2010) Kocak, Taskin; Hinitt, Nicholas; Kocak, Taskin, Department of Computer Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Hinitt, Nicholas, Department of Electrical and Electronic Engineering, University of Bristol, Bristol, United KingdomIn this paper, we explore the feasibility of achieving gigabit baseband throughput using the vast computational power offered by the graphics processors (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, and 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. © 2010 IEEE. © 2010 Elsevier B.V., All rights reserved.Publication Metadata only FPGA design security with Time Division Multiplexed PUFs(2010) Gören, Sezer; Uǧurdaǧ, Hasan Fatih; Yildiz, Abdullah; Özkurt, Özgür; Gören, Sezer, Department of Computer Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Uǧurdaǧ, Hasan Fatih, Department of Computer Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Yildiz, Abdullah, Department of Computer Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Özkurt, Özgür, Department of Computer Engineering, Bahçeşehir Üniversitesi, Istanbul, TurkeyWith the advent of FPGAs, high performance application specific processors can be designed and produced with little investment using a software-like methodology. This ease of design, on the other hand, creates a lot of opportunity for design theft through cloning. A solution to this is bitstream encryption, which is a feature available in rather pricey FPGAs. Physically Unclonable Functions (PUFs) make the same capability possible in ordinary FPGAs. A PUF module provides a signature unique to each chip with the help of manufacturing variations. However, a stable signature requires quite a few bits of PUF, which may not fit in small FPGAs. This paper presents a new PUF based design methodology, which we call Time Division Multiplexed PUF (TDM-PUF). A TDM-PUF divides a single and long PUF into several smaller PUFs run in different time segments. This is made possible by the widely available dynamic partial configuration capability of FPGAs. © 2010 IEEE. © 2010 Elsevier B.V., All rights reserved.Publication Metadata only On the performance of IEEE 802.15.3c millimeter-wave WPANs: PHY and MAC(2010) Zhu, Xiaoyi; Doufexi, Angela; Kocak, Taskin; Zhu, Xiaoyi, Department of Electrical and Electronic Engineering, University of Bristol, Bristol, United Kingdom; Doufexi, Angela, Department of Electrical and Electronic Engineering, University of Bristol, Bristol, United Kingdom; Kocak, Taskin, Department of Electrical and Electronic Engineering, University of Bristol, Bristol, United Kingdom, Department of Computer Engineering, Bahçeşehir Üniversitesi, Istanbul, TurkeyThe large amount of unlicensed bandwidth available in the millimeter-wave has enabled very high data rate wireless applications. The IEEE 802.15 Task Group 3c has completed 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 the newly published standard. Packet error rate (PER) and PHY throughput are simulated for different modes based on a typical 60 GHz channel model. The theoretical MAC throughput is calculated for different packet sizes and modes under different link conditions. The link adaptation mechanism is used to analyze the operating range versus data rate. The results show that very high data rates can be achieved over low distances. © 2010 IEEE. © 2010 Elsevier B.V., All rights reserved.