Computer Sciences Commons^™

Periodic Resource Reallocation In Two-Echelon Repairable Item Inventory Systems, Hoong Chuin Lau, Jie Pan, Huawei Song

Research Collection School Of Computing and Information Systems

Given an existing stock allocation in an inventory system, it is often necessary to perform reallocation over multiple time points to address inventory imbalance and maximize availability. In this paper, we focus on the situation where there are two opportunities to perform reallocation within a replenishment cycle. We derive a mathematical model to determine when and how to perform reallocation. Furthermore, we consider the extension of this model to the situation allowing an arbitrary number of reallocations. Experimental results show that the two-reallocation approach achieves better performance compared with the single-reallocation approach found in the literature. We also illustrate how …

Dual Phase Learning For Large Scale Video Gait Recognition, Jialie Shen, Hwee Hwa Pang, Dacheng Tao, Xuelong Li

Research Collection School Of Computing and Information Systems

Accurate gait recognition from video is a complex process involving heterogenous features, and is still being developed actively. This article introduces a novel framework, called GC2F, for effective and efficient gait recognition and classification. Adopting a ”refinement-and-classification” principle, the framework comprises two components: 1) a classifier to generate advanced probabilistic features from low level gait parameters; and 2) a hidden classifier layer (based on multilayer perceptron neural network) to model the statistical properties of different subject classes. To validate our framework, we have conducted comprehensive experiments with a large test collection, and observed significant improvements in identification accuracy relative to …

Remote Attestation On Function Execution, Liang Gu, Yueqiang Cheng, Xuhua Ding, Robert H. Deng, Yao Guo, Weizhong Shao

Research Collection School Of Computing and Information Systems

Remote attestation provides the basis for one platform to establish trusts on another. In this paper, we consider the problem of attesting the correctness of program executions. We propose to measure the target program and all the objects it depends on, with an assumption that the Secure Kernel and the Trusted Platform Module provide a secure execution environment through process separation. The attestation of the target program begins with a program analysis on the source code or the binary code in order to find out the relevant executables and data objects. Whenever such a data object is accessed or a …

A Primer On Digital Object Identifiers For Law Librarians, Benjamin J. Keele

Library Staff Publications

No abstract provided.

An Investigation Of Multiple Integration Techniques For Information Systems: A Model For Integrating Data Warehousing, Erp, And Soa In Practice, Jessie Burns

CCAC Theses and Dissertations

This study addressed issues associated with implementing multiple data integrators. The process included implementing the same data integrator multiple times or implementing multiple different data integrators. It was shown that single data integrators implementations were failing at high rates. Environments were complicated because there were more acquisitions and mergers now than in the past, companies were required to be competitive while implementations were taking place, and possibly had short implementation time frames.

The main goal of this study was to develop an agile, sturdy, and rigorous model that addressed the needs of companies that found themselves in situations where they …

Early Detection Of Online Auction Opportunistic Sellers Through The Use Of Negative-Positive Feedback, Gregory J. Reinert

CCAC Theses and Dissertations

Apparently fraud is a growth industry. The monetary losses from Internet fraud have increased every year since first officially reported by the Internet Crime Complaint Center (IC3) in 2000. Prior research studies and third-party reports of fraud show rates substantially higher than eBay’s reported negative feedback rate of less than 1%. The conclusion is most buyers are withholding reports of negative feedback.

Researchers Nikitov and Stone in a forensic case study of a single opportunistic eBay seller found buyers sometimes embedded negative comments in positive feedback as a means of avoiding retaliation from sellers and damage to their reputation. This …

A New Multi-Tier Adaptive Military Manet Security Protocol Using Hybrid Cryptography And Signcryption, Atti̇la A. Yavuz, Fati̇h Alagöz, Emi̇n Anarim

Turkish Journal of Electrical Engineering and Computer Sciences

Mobile Ad-hoc NETworks (MANETs) are expected to play an important role in tactical military networks by providing infrastructureless communication. However, maintaining secure and instant information sharing is a difficult task especially for highly dynamic military MANETs. To address this requirement, we propose a new multi-tier adaptive military MANET security protocol using hybrid cryptography and signcryption. In our protocol, we bring novelties to secure military MANET communication for three main points: Cryptographic methods used in MANETs, hybrid key management protocols and structural organization of the military MANETs. As a new approach, we use hybrid cryptography mechanisms and Elliptic Curve Pintsov-Vanstone Signature …

Determination Of Autoregressive Model Orders For Seizure Detection, Serap Aydin

Turkish Journal of Electrical Engineering and Computer Sciences

In the present study, a step-wise least square estimation algorithm (SLSA), implemented in a Matlab package called as ARfit, has been newly applied to clinical data for estimation of the accurate Auto-Regressive (AR) model orders of both normal and ictal EEG series where the power spectral density (PSD) estimations are provided by the Burg Method. The ARfit module is found to be usefull in comparison to a large variety of traditional methods such as Forward Prediction Error (FPE), Akaike's Information Criteria (AIC), Minimum Description Lenght (MDL), and Criterion of Autoregressive Transfer function (CAT) for EEG discrimination. According to tests, the …

Improved Analytical Modulation Transfer Function For Image Intensified Charge Coupled Devices*, Nebi̇ Gül, Murat Efe

Turkish Journal of Electrical Engineering and Computer Sciences

The basic problem of simulation and modeling of Image Intensified Charge Coupled Device (ICCD) is the difference between the analytical Modulation Transfer Function (MTF) formulation used in the model and the experimentally obtained MTF. An investigation into the MTF of ICCD sub-components reveal that the MTF of the Image Intensifier Tube (IIT) is the main factor in this deviation. In this study, a regulation factor for the MTF of 3^{rd} generation IITs has been developed. A commonly used MTF formulation for IITs has been modified to include a regulation factor which has helped produce more precise MTF values for the …

Building Linear Parameter Varying Models Using Adaptation, For The Control Of A Class Of Nonlinear Systems, Coşku Kasnakoğlu

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper a novel method is proposed for constructing linear parameter varying (LPV) system models through adaptation. For a class of nonlinear systems, an LPV model is built using its linear part, and its coefficients are considered as time-varying parameters. The variation in time is controlled by an adaptation scheme with the goal of keeping the trajectories of the LPV system close to those of the original nonlinear system. Using the LPV model as a surrogate, a dynamical controller is built by utilizing self-scheduling methods for LPV systems, and it is shown that this controller will indeed stabilize the …

P2p Collaborative Filtering With Privacy, Ci̇han Kaleli̇, Hüseyi̇n Polat

Turkish Journal of Electrical Engineering and Computer Sciences

With the evolution of the Internet and e-commerce, collaborative filtering (CF) and privacy-preserving collaborative filtering (PPCF) have become popular. The goal in CF is to generate predictions with decent accuracy, efficiently. The main issue in PPCF, however, is achieving such a goal while preserving users' privacy. Many implementations of CF and PPCF techniques proposed so far are centralized. In centralized systems, data is collected and stored by a central server for CF purposes. Centralized storage poses several hazards to users because the central server controls users' data. In this work, we investigate how to produce naïve Bayesian classifier (NBC)-based recommendations …

Comparison Of Daubechies Wavelets For Hurst Parameter Estimation, Cebrai̇l Çi̇ftli̇kli̇, Ali̇ Gezer

Turkish Journal of Electrical Engineering and Computer Sciences

Time scale dependence on the working nature of wavelet analysis makes it a valuable tool for Hurst parameter estimation. Similar to other wavelet-based signal processing applications, the selection of a particular wavelet type and vanishing moment in wavelet based Hurst estimation is a challenging problem. In this paper, we investigate the best Daubechies wavelet in wavelet based Hurst estimation for an exact self similar process, fractional Gaussian noise and how Daubechies vanishing moment affects the Hurst estimation accuracy. Daubechies wavelets are preferred in analysis because increasing vanishing moment does not cause excessive increase of time support of Daubechies wavelets. Thus, …

Differential Power Analysis Resistant Hardware Implementation Of The Rsa Cryptosystem, Kekli̇k Alpteki̇n Bayam, Berna Örs

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, RSA cryptosystem was implemented on hardware, then modified to be resistant against Differential Power Analysis attacks by using the Randomized Table Window method. This is the first FPGA realization of an algorithmic countermeasure which makes RSA resistant to power analysis attacks. Modular exponentiation is realized with Montgomery Modular Multiplication. The Montgomery modular multiplier has been realized with Carry-Save Adders. Carry-Save representation has been used throughout the RSA encryption algorithm. The primarily implemented RSA architecture prevents the extraction of the secret key using Simple Power Analysis attacks. When comparing the protected implementation with the unprotected, it can be …

A Novel Square-Root Domain Realization Of First Order All-Pass Filter, Si̇nem Ölmez, Uğur Çam

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a new square-root domain, first order, all-pass filter based on the MOSFET square law is presented. The proposed filter is designed by using nonlinear mapping on the state variables of a state space description of the transfer function. To the best knowledge of the authors, the filter is the first square-root domain first order all-pass structure designed by using state space synthesis method in the literature. The center frequency of the all-pass filter is not only attainable at megahertz frequencies but also tunable by an external bias current. The proposed filter operated 2.5 V supply voltage is …

Experimental Studies Of A Scaled-Down Tsr-Based Svc And Tcr-Based Svc Prototype For Voltage Regulation And Compensation, Ayetül Gelen, Tankut Yalçinöz

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, prototypes of two shunt flexible AC transmission system (FACTS) devices, a thyristor switched reactor (TSR)-based static VAr compensator (SVC) and a thyristor controlled reactor (TCR)-based static VAr compensator- have been developed. The design and testing of both a TSR-based SVC and a TCR-based SVC are accomplished in the Power Systems Research Laboratory of Nigde University. The TSR-based SVC and TCR-based SVC devices are studied in three-bus and single machine infinite bus systems for three-phase static load conditions. The effects of TSR-based SVC and TCR-based SVC devices on load voltages are also analyzed. Experimental results show that significant …

Robust Multimedia Watermarking: Hidden Markov Model Approach For Video Sequences, Ersi̇n Elbaşi

Turkish Journal of Electrical Engineering and Computer Sciences

Because of the large amount of frames, similarity between frames and temporal attacks (frame dropping, frame averaging, frame swapping etc.), the process for video watermarking is more difficult than that for image watermarking. Current image watermarking methods are limited to solve all these difficulties. We propose a novel video watermarking system based on the Hidden Markov Model (HMM). This novel watermarking scheme splits the video sequences into a Group of Pictures (GOP) with HMM. Portions of the binary watermark are embedded into each GOP with a wavelet domain watermarking algorithm. The embedding process is the standard additive algorithm [1] in …

A New Chaotic Attractor From General Lorenz System Family And Its Electronic Experimental Implementation, İhsan Pehli̇van, Yilmaz Uyaroğlu

Turkish Journal of Electrical Engineering and Computer Sciences

This article introduces a novel three-dimensional continuous autonomous chaotic system with six terms and two quadratic nonlinearities. The new system contains two variational parameters and exhibits Lorenz-like attractors in numerical simulations and experimental measurements. The basic dynamical properties of the new system are analyzed by means of equilibrium points, eigenvalue structures, and Lyapunov exponents. The new system examined in Matlab-Simulink^{\textregistered} and Orcad-PSpice^{\textregistered}. An electronic circuit realization of the proposed system is presented using analog electronic elements such as capacitors, resistors, operational amplifiers and multipliers. The behaviour of the realized system is evaluated with computer simulations.

An Rfid Based Indoor Tracking Method For Navigating Visually Impaired People, Ruşen Öktem, Eli̇f Aydin

Turkish Journal of Electrical Engineering and Computer Sciences

This paper tackles the RFID based tracking problem in an obscured indoor environment. The proposed solution is an integral part of a navigation aid for guiding visually impaired people in a store. It uses RF signal strengths and is based on the Bayes Decision Theory. An observation vector is formed by received radio signal strength indication values, transmitted from three transmitters at distinct frequencies in the UHF band. The indoor area is divided into square grids, where each grid is considered as a class. The problem of tracking is expressed as classifying the observed radio signal strengths to the most …

Stator Resistance Estimation Using Ann In Dtc Im Drives, Mustafa Aktaş, H. İbrahi̇m Okumuş

Turkish Journal of Electrical Engineering and Computer Sciences

Torque control of induction motors (IM) requires accurate estimation of the flux in the motor. But the flux estimate, when estimated from the stator circuit variables, is highly dependent on the stator resistance of the IM. As a result, the flux estimate is prone to errors due to variation in the stator resistance, especially at low stator frequencies. In this paper, an Artificial Neural Network (ANN) is used to adjust the stator resistance of an IM. A back propagation training algorithm was used in training the neural network for the simulation. The proposed ANN resistance estimator has shown good performance …

K-Anonymity Based Framework For Privacy Preserving Data Collection In Wireless Sensor Networks, Hayretdi̇n Bahşi̇, Albert Levi̇

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, k-anonymity notion is adopted to be used in wireless sensor networks (WSN) as a security framework with two levels of privacy. A base level of privacy is provided for the data shared with semi-trusted sink and a deeper level of privacy is provided against eavesdroppers. In the proposed method, some portions of data are encrypted and the rest is generalized. Generalization shortens the size of the data transmitted in the network causing energy saving at the cost of information loss. On the other hand, encryption provides anonymization with no information loss and without saving energy. Thus, there …

Stochastic Stability Of The Discrete-Time Constrained Extended Kalman Filter, Levent Özbek, Esi̇n Köksal Babacan, Murat Efe

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, stability of the projection-based constrained discrete-time extended Kalman filter (EKF) as applied to nonlinear systems in a stochastic framework has been studied. It has been shown that like the unconstrained EKF, the estimation error of the EKF with known constraints on the states remains bounded when the initial error and noise terms are small, and the solution of the Riccati difference equation remains positive definite and bounded. Stability results are verified and performance of the constrained EKF is demonstrated through simulations on a nonlinear engineering example.

Relativistic Electromagnetism In Rotating Media, Pierre Hillion

Turkish Journal of Electrical Engineering and Computer Sciences

This work concerns relativistic electromagnetism in a cylindrical Frenet-Serret frame. The tensor formalism of Maxwell's equations and electromagnetic fields in a vacuum is first developed in terms of cylindrical coordinates and afterwards applied to a rotating frame using the relativistic Trocheris-Takeno description of rotations. The metric ds^2 = g_{\mu \nu} dx^{\mu} dx^{\nu} of this frame is then obtained to find the determinant g of the g_{\mu \nu} matrix intervening in the relativistic Maxwell's equations, where the Greek indices take on the values 1,2,3,4. The propagation of harmonic cylindrical waves in rotating media is analyzed and it is shown that these …

Remote Sensing Applications Of Hf Skywave Radar: The Australian Experience, Stuart Anderson

Turkish Journal of Electrical Engineering and Computer Sciences

Australia has conducted research into over-the-horizon radar (OTHR) for almost sixty years. Early programs focused exclusively on military capabilities, such as the detection of aircraft, missiles and ships, but in 1974 a team was formed to design a new OTHR for which a remote sensing mission was proposed. Oceanic wind mapping experiments in 1977-78 yielded promising results so remote sensing became a recognised mission assigned to the new radar, known as Jindalee Stage B. This capability was progressively expanded over the period 1982-87 to include mapping of wave height and other oceanographic variables. A real-time data link to the Australian …

Dual-Use Of Compact Hf Radars For The Detection Of Mid- And Large-Size Vessels, Hugh Roarty, Don Barrick, Josh Kohut, Scott Glenn

Turkish Journal of Electrical Engineering and Computer Sciences

This paper describes the development of the SeaSonde High Frequency Radar system into a dual-use application for the mapping of ocean surface currents and detection of ships at sea. This development entailed the creation of a new radar waveform that would permit this dual-use as well as a detection algorithm to identify the ships in the radar spectra. The detection algorithm utilizes two methods for calculating a background signal level: an infinite impulse response (IIR) filter and a two-dimensional median filter. These two methods are employed simultaneously with multiple length averaging times to maximize the number of detections. The initial …

Oceanography Radar System Wera: Features, Accuracy, Reliability And Limitations, Thomas Helzel, Matthias Kniephoff, Leif Petersen

Turkish Journal of Electrical Engineering and Computer Sciences

The WERA system (WavE RAdar) is a shore based remote sensing system to monitor ocean surface currents, waves and wind direction. This long range, high resolution monitoring system based on short radio wave radar technology. The vertical polarised electromagnetic wave is coupled to the conductive ocean surface and follows the curvature of the earth. This over the horizon oceanography radar can pick up back-scattered signals from the rough ocean surface (Bragg effect) from ranges of up to 200 km. The physical background, technical concept and environmental boundary conditions are explained. Results for various installations from all over the world demonstrates …

Modeling And Simulation Strategies In High Frequency Surface Wave Radars, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

Surface Wave High Frequency Radars (SWHFR) are taken into account in the content of modeling and simulation challenges. Examples related to multi-mixed path surface wave propagation, radar cross section (RCS) prediction, and total radar echo showing target, clutter, noise, and interference are presented.

A Review Of High Frequency Surface Wave Radar For Detection And Tracking Of Ships, Tony Ponsford, Jian Wang

Turkish Journal of Electrical Engineering and Computer Sciences

In today's resource-driven economy, maritime nations are claiming economic borders that extend beyond the continental shelf or the 200 nautical mile (nm) Exclusive Economic Zone (EEZ). However, claiming such large economic area places responsibilities on the parent nation to exercise jurisdiction through surveillance and enforcement. The requirement to see beyond the horizon has long been a goal of maritime security forces. Today, this is largely dependent on cooperative vessels voluntarily communicating their intentions to local shore-side authorities, as well as on those vessel sightings reported by patrollers. Recent advances in technology provide maritime nations with options to provide more systematic …

Implementation Of Method For Operating Multiple High Frequency Surface Wave Radars On A Common Carrier Frequency, Ryan Riddolls

Turkish Journal of Electrical Engineering and Computer Sciences

The increasing use of High Frequency Surface Wave Radar (HFSWR) for the surveillance of coastal regions is faced with the problem of limited channel availability in the electromagnetic spectrum. Thus, there is a need for multiple radars to share a common frequency channel. Proof-of-concept work is presented here for a method to operate multiple radar systems on a common carrier frequency. A review is provided of an existing concept where a common waveform is modulated by tones varying by a few hertz across the different radars. The signals from the different radars are separated by either pulse-domain filtering or Doppler …

Nonlinear Scattering At Hf: Prospects For Exploitation In Oth Radar Systems, Stuart Anderson

Turkish Journal of Electrical Engineering and Computer Sciences

HF skywave `over-the-horizon' radars experience exceptionally high levels of clutter from the earth's surface as a consequence of their `look-down' propagation geometry. While Doppler processing is effective in separating aircraft echoes from the clutter, thereby enabling detection, the same does not always hold for slow moving targets. In particular, ship echoes occupy the same region of Doppler space as the sea clutter, so the likelihood of target echo obscuration is high. By exploiting the known dependence of the characteristic spectral form of the clutter Doppler spectrum on radar frequency and other parameters, HF radars can maximise the prospects for detectability …

Propagation Modeling And Path Loss Prediction Tools For High Frequency Surface Wave Radars, Gökhan Apaydin, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

Propagation modeling and simulation approaches for the use of High Frequency Surface Wave Radar (HFSWR) are discussed. HFSWR uses vertically polarized surface waves along multi-mixed paths in the lower HF band (3 MHz - 15 MHz). Various numerical propagators are reviewed with an early analytical model. Split Step Fast Fourier Transformation, finite- difference, and finite-element solutions of the well-known one-way, forward propagation Parabolic Equation (PE) model are presented. MATLAB-based numerical propagation prediction tools based on these models are listed. Tests and comparisons among these analytical and numerical tools are given for some canonical surface wave propagation scenarios. The Millington effect …