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Articles 5371 - 5400 of 7211

Full-Text Articles in Computer Engineering

Book Review: Professional Penetration Testing: Creating And Learning In A Hacking Lab 2e, Joshua Bartolomie Jan 2013

Book Review: Professional Penetration Testing: Creating And Learning In A Hacking Lab 2e, Joshua Bartolomie

Journal of Digital Forensics, Security and Law

Organizations often strive for proactive information security programs in an effort to limit occurrence and impact of security breaches. However, traditional security programs run the risk of being unable to provide adequate insight and proactive awareness into real attack vectors that may exist within their organizations. With attack methods and efforts becoming increasingly aggressive, and effective, organizations must take equally assertive measures to protect their critical information and assets. Penetration testing is one of those tools that is often misunderstood, overlooked, and undervalued. A true adversary would not hesitate to exploit every potential to gain entry or cause a disruption …


Technology Corner: Calculating The Number Of Android Lock Patterns: An Unfinished Study In Number Theory, Gary C. Kessler Jan 2013

Technology Corner: Calculating The Number Of Android Lock Patterns: An Unfinished Study In Number Theory, Gary C. Kessler

Journal of Digital Forensics, Security and Law

Although one is unlikely to ever want to brute-force an Android lock pattern, many do wonder about the relative strength of the lock pattern versus a multidigit personal identification number (PIN). It becomes obvious pretty quickly that there are many more lock patterns than the 10,000 possible four-digit PINs.


Science Column: Reconstruction: The Experimental Side Of Digital Forensics, Fred Cohen Jan 2013

Science Column: Reconstruction: The Experimental Side Of Digital Forensics, Fred Cohen

Journal of Digital Forensics, Security and Law

Many in digital forensics seem to forget that the science part of digital forensics means experimentation and that implies a whole lot of things that most practitioners never learned.


Book Review: Iphone And Ios Forensic: Investigation, Analysis And Mobile Security For Apple Iphone, Ipad And Ios Devices, Simson Garfinkel Jan 2013

Book Review: Iphone And Ios Forensic: Investigation, Analysis And Mobile Security For Apple Iphone, Ipad And Ios Devices, Simson Garfinkel

Journal of Digital Forensics, Security and Law

In April 2011 news outlets around the world revealed shocking news about Apple’s iPhone: for reasons that were not apparently clear, every iPhone contained a small SQLite database that logged where and when the user had been whenever the phone was turned on, and those records went back for pretty much as long as the user had owned their phone. Apple eventually declared that the data cache was the result of a bug and issued a software update to prune the database (it had previously grown without limit). Privacy activists rejoiced that their beloved iPhones were once again trustworthy. But …


Table Of Contents Jan 2013

Table Of Contents

Journal of Digital Forensics, Security and Law

No abstract provided.


Prevention And Detection Of Intrusions In Wireless Sensor Networks, Ismail Butun Jan 2013

Prevention And Detection Of Intrusions In Wireless Sensor Networks, Ismail Butun

USF Tampa Graduate Theses and Dissertations

Wireless Sensor Networks (WSNs) continue to grow as one of the most exciting and challenging research areas of engineering. They are characterized by severely constrained computational and energy

resources and also restricted by the ad-hoc network operational

environment. They pose unique challenges, due to limited power

supplies, low transmission bandwidth, small memory sizes and limited energy. Therefore, security techniques used in traditional networks cannot be directly adopted. So, new ideas and approaches are needed, in order to increase the overall security of the network. Security applications in such resource constrained WSNs with minimum overhead provides significant challenges, and is the …


Time Resolved Gain And Excess Noise Properties Of Ingaas/Inalas Avalanche Photodiodes With Cascaded Discrete Gain Layer Multiplication Regions, Georges M. Williams, David A. Ramirez, Majeed M. Hayat, Andrew S. Huntington Jan 2013

Time Resolved Gain And Excess Noise Properties Of Ingaas/Inalas Avalanche Photodiodes With Cascaded Discrete Gain Layer Multiplication Regions, Georges M. Williams, David A. Ramirez, Majeed M. Hayat, Andrew S. Huntington

Electrical and Computer Engineering Faculty Research and Publications

To predict pulse detection performance when implemented in high speed photoreceivers, temporally resolved measurements of a 10-stage InAlAs/InGaAs single carrier multiplication (SCM) avalanche photodiode (APD)'s avalanche response to short multi-photon laser pulses were explained using instantaneous (time resolved) pulse height statistics of the device's impulse response. Numeric models of the junction carrier populations as a function of the time following injection of a primary photo-electron were used to create the probability density functions (pdfs) of the instances of the avalanche buildup process. The numeric pdfs were used to generate low frequency gain and excess noise models, which were in good …


Effect Of Hydrodynamic Force On Microcantilever Vibrations: Applications To Liquid-Phase Chemical Sensing, I. Dufour, E. Lemaire, B. Caillard, H. Debeda, C. Lucat, Stephen M. Heinrich, Fabien Josse, O. Brand Jan 2013

Effect Of Hydrodynamic Force On Microcantilever Vibrations: Applications To Liquid-Phase Chemical Sensing, I. Dufour, E. Lemaire, B. Caillard, H. Debeda, C. Lucat, Stephen M. Heinrich, Fabien Josse, O. Brand

Electrical and Computer Engineering Faculty Research and Publications

At the microscale, cantilever vibrations depend not only on the microstructure’s properties and geometry but also on the properties of the surrounding medium. In fact, when a microcantilever vibrates in a fluid, the fluid offers resistance to the motion of the beam. The study of the influence of the hydrodynamic force on the microcantilever’s vibrational spectrum can be used to either (1) optimize the use of microcantilevers for chemical detection in liquid media or (2) extract the mechanical properties of the fluid. The classical method for application (1) in gas is to operate the microcantilever in the dynamic transverse bending …


Performance Evaluation And Comparison Of Distributed Messaging Using Message Oriented Middleware, Naveen Mupparaju Jan 2013

Performance Evaluation And Comparison Of Distributed Messaging Using Message Oriented Middleware, Naveen Mupparaju

UNF Graduate Theses and Dissertations

Message Oriented Middleware (MOM) is an enabling technology for modern event- driven applications that are typically based on publish/subscribe communication [Eugster03]. Enterprises typically contain hundreds of applications operating in environments with diverse databases and operating systems. Integration of these applications is required to coordinate the business process. Unfortunately, this is no easy task. Enterprise Integration, according to Brosey et al. (2001), "aims to connect and combines people, processes, systems, and technologies to ensure that the right people and the right processes have the right information and the right resources at the right time"[Brosey01]. Communication between different applications can be achieved …


Forecasting Natural Gas Demand For Electric Power Generation, Ronald H. Brown, George Corliss, Richard J. Povinelli Jan 2013

Forecasting Natural Gas Demand For Electric Power Generation, Ronald H. Brown, George Corliss, Richard J. Povinelli

Electrical and Computer Engineering Faculty Research and Publications

No abstract provided.


Optimal Network Topologies And Resource Mappings For Heterogeneous Networks-On-Chip, Haera Chung Jan 2013

Optimal Network Topologies And Resource Mappings For Heterogeneous Networks-On-Chip, Haera Chung

Dissertations and Theses

Communication has become a bottleneck for modern microprocessors and multi-core chips because metal wires don't scale. The problem becomes worse as the number of components increases and chips become bigger. Traditional Systems-on-Chips (SoCs) interconnect architectures are based on shared-bus communication, which can carry only one communication transaction at a time. This limits the communication bandwidth and scalability. Networks-on-Chip (NoC) were proposed as a promising solution for designing large and complex SoCs. The NoC paradigm provides better scalability and reusability for future SoCs, however, long-distance multi-hop communication through traditional metal wires suffers from both high latency and power consumption. A radical …


Artificial Immunity-Based Induction Motor Bearing Fault Diagnosis, Hakan Çaliş, Abdülkadi̇r Çakir, Emre Dandil Jan 2013

Artificial Immunity-Based Induction Motor Bearing Fault Diagnosis, Hakan Çaliş, Abdülkadi̇r Çakir, Emre Dandil

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, the artificial immunity of the negative selection algorithm is used for bearing fault detection. It is implemented in MATLAB-based graphical user interface software. The developed software uses amplitudes of the vibration signal in the time and frequency domains. Outer, inner, and ball defects in the bearings of the induction motor are detected by anomaly monitoring. The time instants of the fault occurrence and fault level are determined according to the number of activated detectors. Anomaly detection in the frequency domain is implemented by monitoring the fault indicator bearing frequencies and harmonics, calculated using the bearing dimensions and …


The Vortex Effect Of Francis Turbine In Electric Power Generation, Veli̇ Türkmenoğlu Jan 2013

The Vortex Effect Of Francis Turbine In Electric Power Generation, Veli̇ Türkmenoğlu

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, the vibration effects of a vortex that occurred in high-head Francis turbines and an alternator are examined. The vortex effect, which directly affects the efficiency and the quality of the energy, was tested at the DarÔøΩca-1 hydroelectric power plant (HPP) located in Ordu Province, Turkey. Formed by undissolved oxygen in the water, the vortex effect, which is parallel to the alternator load, causes tremendous vibration within the alternator and Francis turbine bearings. This problem, which has a direct negative effect on the alternator capacity, was solved by adding an air-admission system. In doing so, power production was …


A Practical Disturbance Generator To Test Performances Of Various Power Quality Mitigation Devices, Ahmet Teke, Mehmet Emi̇n Meral, Mehmet Tümay, Mehmet Uğraş Cuma Jan 2013

A Practical Disturbance Generator To Test Performances Of Various Power Quality Mitigation Devices, Ahmet Teke, Mehmet Emi̇n Meral, Mehmet Tümay, Mehmet Uğraş Cuma

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a practical thyristor-based 3-phase sag/swell/outage generator (disturbance generator) is designed to test various power quality mitigation devices (PQMDs), such as solid state transfer switch (SSTS), static voltage compensator (SVC), and uninterruptible power supply. The latest technological disturbance generators (DGs) and the proposed DG are comprehensively discussed and compared with focus on usefulness, economic aspects, and simplicity. The proposed DG is used for experimentally generating different fault conditions and testing a SSTS. The comparisons and analyses show that the proposed DG is an optimum and simple solution to generate sag, swell, unbalance, overvoltage, undervoltage, and outage to test …


Circulating Current Analysis Between Strands In Armature Winding Of A Turbo-Generator Using Analytical Model, Karim Abbaszadeh, Farhad Rezaee Alam Jan 2013

Circulating Current Analysis Between Strands In Armature Winding Of A Turbo-Generator Using Analytical Model, Karim Abbaszadeh, Farhad Rezaee Alam

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the circulating current analysis between strands is studied while considering the different transpositions in the active part and without considering the transposition in the end winding region. First, this analysis is done while only considering the slot region, and then the end winding region is added to the model. The model used for this analysis is a circuit model, including the resistance and inductance of the strands and their induced back-electromotive force (EMF). The back-EMF sources and inductances are calculated through a 2D finite element analysis (FEA) of the active part and a 3D FEA for the …


Pc-Based Data Acquisition System For Plc-Controlled Linear Switched Reluctance Motor, Mahi̇r Dursun, Semi̇h Özden Jan 2013

Pc-Based Data Acquisition System For Plc-Controlled Linear Switched Reluctance Motor, Mahi̇r Dursun, Semi̇h Özden

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a linear switched reluctance motor (LSRM) with 250 W, 6/4 poles, 3 phases, and 24 V was controlled with a programmable logic controller (PLC). Some parameters of the LSRM were set, and for PC monitoring, software developed by the authors was used. A serial port was used for communication between the PC and the PLC. The software was developed with Visual C#.Net 2008 for monitoring and controlling. This user interference allows for controlling of the motor's travelling distance with a running strategy. The first and second destination can be defined and the system provides that the motor …


Current-Mode Quadrature Oscillator Based On Cccdtas With Noninteractive Dual-Current Control For Both Condition Of Oscillation And Frequency Of Oscillation, Adirek Jantakun, Winai Jaikla Jan 2013

Current-Mode Quadrature Oscillator Based On Cccdtas With Noninteractive Dual-Current Control For Both Condition Of Oscillation And Frequency Of Oscillation, Adirek Jantakun, Winai Jaikla

Turkish Journal of Electrical Engineering and Computer Sciences

The realization of 2 current-mode quadrature oscillators using current-controlled current differencing transconductance amplifiers (CCCDTAs) and grounded capacitors is presented. The proposed oscillators can provide 2 sinusoidal output currents with a 90° phase difference. They enable noninteractive dual-current control for both the condition of oscillation and the frequency ofi oscillation. The high-output impedances of the configurations enable the circuit to be cascaded without additional current buffers. The use of only grounded capacitors is ideal for integration. The circuit performances are depicted through PSpice simulations; they show good agreement to theoretical anticipation.


Modified Iterated Extended Kalman Particle Filter For Single Satellite Passive Tracking, Panlong Wu, Jianshou Kong, Yuming Bo Jan 2013

Modified Iterated Extended Kalman Particle Filter For Single Satellite Passive Tracking, Panlong Wu, Jianshou Kong, Yuming Bo

Turkish Journal of Electrical Engineering and Computer Sciences

Single satellite-to-satellite passive tracking techniques have great significance in space surveillance systems. A new passive modified iterated extended Kalman particle filter (MIEKPF) using bearings-only measurements in the Earth-Centered Inertial Coordinate System is proposed. The modified iterated extended Kalman filter (MIEKF), with a new maximum likelihood iteration termination criterion, is used to generate the proposal distribution of the MIEKPF. Moreover, a new measurement update equation of the MIEKF is derived by modifying the objective function of the Gauss--Newton iteration. The approximated second-order linearized state propagation equation, Jacobian matrix of state transfer, and measurement equations are derived in satellite 2-body movement. The …


The Development Of A Hardware- And Software-Based Simulation Platform For The Training Of Driver Candidates, Abdullah Çavuşoğlu, İsmai̇l Kurnaz Jan 2013

The Development Of A Hardware- And Software-Based Simulation Platform For The Training Of Driver Candidates, Abdullah Çavuşoğlu, İsmai̇l Kurnaz

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a traffic simulation system (TSS) to provide novice driver candidates with opportunities for training and testing has been developed. Autonomous vehicles that follow the flow of traffic in a microsimulation environment were prepared using a hierarchical concurrent state machine. Autonomous vehicles are skilled and have behavioral aspects such as tracking the lanes, following the vehicles, complying with traffic rules, decelerating, accelerating, and intersection crossings. These driver behaviors are parameterized to allow the autonomous agents to act while disregarding the rules (i.e. aggressive behaviors) or behaving normally. The TSS is operated in 3 different modes, namely the orientation, …


Spatiotemporal Model Checking Of Location And Mobility Related Security Policy Specifications, Devri̇m Ünal, Mehmet Ufuk Çağlayan Jan 2013

Spatiotemporal Model Checking Of Location And Mobility Related Security Policy Specifications, Devri̇m Ünal, Mehmet Ufuk Çağlayan

Turkish Journal of Electrical Engineering and Computer Sciences

For the formal verification of security in mobile networks, a requirement is that security policies associated with mobility and location constraints are formally specified and verified. For the formal specification and verification of security policies, formal methods ensure that a given network configuration that includes certain network elements satisfies a given security policy. A process calculus based approach is presented, where ambient calculus is used for formal specification of security policies and ambient logic is used for formal representation of mobility and location constraints. A spatiotemporal model checking algorithm is presented for the model checking of formal specifications in ambient …


A Time--Memory Trade-Off Approach For The Solution Of Nonlinear Equation Systems, Hüseyi̇n Demi̇rci̇, Mahmut Şami̇l Sağiroğlu, Muhammed Oğuzhan Külekci̇ Jan 2013

A Time--Memory Trade-Off Approach For The Solution Of Nonlinear Equation Systems, Hüseyi̇n Demi̇rci̇, Mahmut Şami̇l Sağiroğlu, Muhammed Oğuzhan Külekci̇

Turkish Journal of Electrical Engineering and Computer Sciences

We propose a memory-based method for the solution of a specific type of nonlinear equation systems. We observe that when the equations in a system can be separated into 2 parts, where each subset contains fewer parameters than the whole set of equations, the system can be solved faster with a preprocessing phase. We show that reduced rounds of AES produce such a system under a chosen plaintext scenario. This observation enables us to solve that system within a practically applicable complexity of 2^{37} operations where a brute force approach requires 2^{72} trials. The method can be used for the …


Solution To The Unit Commitment Problem Using An Artificial Neural Network, Mehdi Zareian Jahromi, Mohammad Mehdi Hosseini Bioki, Masoud Rashidi Nejad, Roohollah Fadaeinedjad Jan 2013

Solution To The Unit Commitment Problem Using An Artificial Neural Network, Mehdi Zareian Jahromi, Mohammad Mehdi Hosseini Bioki, Masoud Rashidi Nejad, Roohollah Fadaeinedjad

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a real-time solution to the unit commitment problem by considering different constraints like ramp-up rate, unit operation emissions, next hours load, and minimum down time. In this method, an optimized trade-off between cost and emission has been taken into consideration. The effectiveness of the proposed method was verified by the significant outcomes demonstrated.


A Comparative Study In Power Oscillation Damping By Statcom And Sssc Based On The Multiobjective Pso Algorithm, Ali Ajami, Mehdi Armaghan Jan 2013

A Comparative Study In Power Oscillation Damping By Statcom And Sssc Based On The Multiobjective Pso Algorithm, Ali Ajami, Mehdi Armaghan

Turkish Journal of Electrical Engineering and Computer Sciences

To improve the damping of power system oscillations by supplementary controller design for the static synchronous series compensator (SSSC) and static synchronous compensator (STATCOM), a multiobjective function based on the particle swarm optimization (PSO) algorithm for solving this optimization problem is introduced. The presented objective function includes the damping factor and the damping ratio of the lightly damped and undamped electromechanical modes. These controllers are adjusted to concurrently transfer the lightly damped and undamped electromechanical modes to a recommended region in the s-plane. For this purpose, the reduced linearized Phillips-Heffron model of the power system with a single machine and …


Optimal Release Policies For A Software System With Warranty Cost And Change-Point Phenomenon, D.R. Prince Williams Jan 2013

Optimal Release Policies For A Software System With Warranty Cost And Change-Point Phenomenon, D.R. Prince Williams

Turkish Journal of Electrical Engineering and Computer Sciences

Determining the software quality and release time of the software is an important role of software reliability. Software reliability growth models (SRGMs) are applications of software reliability. The change-point is defined as the prominent change in the software testing time, in connection with the quality of a software error occurrence or error-detection phenomenon. As a result, the software reliability growth process, based on the change-point, affects the precision of the software reliability prediction, based on the SRGMs. To find the accurate total expected delivery cost with a suitable warranty period of the software system, a new cost model for the …


System Designs To Perform Bioinformatics Sequence Alignment, Çağlar Yilmaz, Mustafa Gök Jan 2013

System Designs To Perform Bioinformatics Sequence Alignment, Çağlar Yilmaz, Mustafa Gök

Turkish Journal of Electrical Engineering and Computer Sciences

The emerging field of bioinformatics uses computing as a tool to understand biology. Biological data of organisms (nucleotide and amino acid sequences) are stored in databases that contain billions of records. In order to process the vast amount of data in a reasonable time, high-performance analysis systems are developed. The main operation shared by the analysis tools is the search for matching patterns between sequences of data (sequence alignment). In this paper, we present 2 systems that can perform pairwise and multiple sequence alignment operations. Through the optimized design methods, proposed systems achieve up to 3.6 times more performance compared …


Characterization Of Internal Disturbances And External Faults In Transformers Using An S-Transform--Based Algorithm, Abdolaziz Ashrafian, Mehrdad Rostami, Gevorg .B Gharehpetian Jan 2013

Characterization Of Internal Disturbances And External Faults In Transformers Using An S-Transform--Based Algorithm, Abdolaziz Ashrafian, Mehrdad Rostami, Gevorg .B Gharehpetian

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the S-transform is used to discriminate between the internal disturbances and external faults of transformers. The proposed algorithm consists of 2 stages. The internal disturbances and the external faults are distinguished in the first stage. Next, the S-transform is applied to differential currents of faulty phases and the absolute deviation of the S-matrix is calculated. The relay scheme issues a trip signal in the case of an internal fault, according to the absolute deviation of the S-matrix. The scheme is implemented in a MATLAB environment and the inputs are differential currents, derived from EMTP software. In order …


Exergoeconomic Analysis Of A Solar Photovoltaic System In İstanbul, Turkey, Ercan İzgi̇, Yunus Emre Akkaya Jan 2013

Exergoeconomic Analysis Of A Solar Photovoltaic System In İstanbul, Turkey, Ercan İzgi̇, Yunus Emre Akkaya

Turkish Journal of Electrical Engineering and Computer Sciences

This paper deals with the exergoeconomic analysis of a 750-Wp solar photovoltaic (PV) system that is constructed at the Meteorology Park of İstanbul Technical University (41.102° N, 29.02° E) in İstanbul, Turkey. It is known that seasonal differences cause a variation in the exergoeconomic parameters (energy and exergy loss rates) of solar PV systems. Due to this perspective, for regional climatic parameters 2 months are selected: April to represent the spring and August to represent the summer. Within this research, first the exergy analysis is performed on the system and then the economic values of the results are evaluated using …


Solution Of Transient Stability-Constrained Optimal Power Flow Using Artificial Bee Colony Algorithm, Kürşat Ayan, Ulaş Kiliç Jan 2013

Solution Of Transient Stability-Constrained Optimal Power Flow Using Artificial Bee Colony Algorithm, Kürşat Ayan, Ulaş Kiliç

Turkish Journal of Electrical Engineering and Computer Sciences

The transient stability constraint should be taken into consideration for the solution of the optimization problems in power systems. This paper presents a solution for the transient stability-constrained optimal power flow (TSCOPF) by a novel approach based on the artificial bee colony algorithm. The formulas of TSCOPF are derived through the addition of rotor angle inequality constraints into optimal power flow relationships. In this nonlinear optimization problem, the objective function is taken into consideration as the fuel cost of the system. The proposed approach is tested on both a WSCC 3-generator, 9-bus system and a IEEE 30-bus system, and the …


Symbol Detection Using The Differential Evolution Algorithm In Mimo-Ofdm Systems, Muhammet Nuri̇ Seyman, Necmi̇ Taşpinar Jan 2013

Symbol Detection Using The Differential Evolution Algorithm In Mimo-Ofdm Systems, Muhammet Nuri̇ Seyman, Necmi̇ Taşpinar

Turkish Journal of Electrical Engineering and Computer Sciences

Channel estimation and symbol detection in multiple-input and multiple-output (MIMO)-orthogonal frequency division multiplexing (OFDM) systems are essential tasks. Although the maximum likelihood (ML) detector reveals excellent performance for symbol detection, the computational complexity of this algorithm is extremely high in systems with more transmitter antennas and high-order constellation size. In this paper, we propose the differential evolution (DE) algorithm in order to reduce the search space of the ML detector and the computational complexity of symbol detection in MIMO-OFDM systems. The DE algorithm is also compared to some heuristic approaches, such as the genetic algorithm and particle swarm optimization. According …


Stability Analysis Of Time-Delayed Dc Motor Speed Control System, Saffet Ayasun Jan 2013

Stability Analysis Of Time-Delayed Dc Motor Speed Control System, Saffet Ayasun

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the stability of time-delayed DC motor speed control systems is analyzed. The measurement devices and communication links used by networked control systems, cause a significant amount of time delays. The stability boundary of the system in terms of the time delay is theoretically determined and an expression is obtained to compute the delay margin in terms of system parameters. The delay margin is defined as the maximum amount of time delay for which the DC motor speed control system is marginally stable. The results indicate that the system becomes unstable if the time delay exceeds the delay …