Computer Engineering Commons^™

Skewed Alpha-Stable Distributions For Modeling And Classification Of Musical Instruments, Mehmet Erdal Özbek, Mehmet Emre Çek, Feri̇t Acar Savaci

Turkish Journal of Electrical Engineering and Computer Sciences

Music information retrieval and particularly musical instrument classification has become a very popular research area for the last few decades. Although in the literature many feature sets have been proposed to represent the musical instrument sounds, there is still need to find a superior feature set to achieve better classification performance. In this paper, we propose to use the parameters of skewed alpha-stable distribution of sub-band wavelet coefficients of musical sounds as features and show the effectiveness of this new feature set for musical instrument classification. We compare the classification performance with the features constructed from the parameters of generalized …

A Pseudo Spot Price Of Electricity Algorithm Applied To Environmental Economic Active Power Dispatch Problem, Celal Yaşar

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, an environmental economic active power dispatch problem is transformed into an optimization problem with a single-objective function by applying the weighted sum method (WSM) and the conic scalarization method (CSM). A pseudo spot price of electricity algorithm (PSPA) is used to solve the transformed problem. This is demonstrated on an example problem, which is a lossy electrical power system having only thermal units The WSM and CSM methods are applied to the example problem, and the weight factor values of these methods is increased from 0 to 1 by a step size of 0.1. For each possible …

Optimal In Vitro Realization Of Pulsatile Coronary Artery Flow Waveforms Using Closed-Loop Feedback Algorithms With Multiple Flow Control Devices, Serdar Yilmaz, Onur Toker, Nurullah Arslan, Herman Sedef

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we study optimal in vitro realization of pulsatile coronary artery flows using newly proposed closed-loop feedback algorithms with a clearly defined mathematical performance objective, and we compare several flow control device technologies in terms of their ability to generate pulsatile flow signals as accurately as possible. In the literature, there are several published results for in vitro pulsatile flow realization systems. However, most of the proposed systems operate in an open-loop setting and use a single flow control device, and their performance is assessed mostly by graphical means without a clearly defined mathematical performance objective. Furthermore, some …

A Novel Approach For Optimal Allocation Of Distributed Generations Based On Static Voltage Stability Margin, Mohsen Rezaie Estabragh, Mohsen Mohammadian, Mehdi Shafiee

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a newly developed approach to find the optimal location of distributed generations (DGs) to improve power system voltage stability margin and reduce losses incorporating the constraints. The loadability limit index is used to assess the static voltage stability security margin, which is associated with the point of voltage collapse limit. Based on this, a toolbox is developed to recognize the loadability margin in power networks. Finally, the mentioned problem is modeled as a nonlinear and multiobjective optimization problem. The proposed method establishes a tradeoff between the security index and power losses in DG placement using the hybrid …

A Novel Motor Speed Calculation Method Using Square Wave Speed Sensor Signals Via Fast Fourier Transform, Hayri̇ Arabaci, Osman Bi̇lgi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a novel motor speed measurement method and experimental results using the fast Fourier transform (FFT). Motor speed is obtained using the square wave output signal of a speed sensor. In the proposed method, the speed can be measured in a wide range, and transient speed changes can also be clearly observed. The experiments were conducted during start-up and in steady state. The sampled speed data were transformed to frequency spectrums using the FFT. The frequency, which corresponds to the maximum amplitude in the spectrum, was used to calculate the motor speed. The test results show that the …

Voltage Stability Via Energy Function Analysis On Reduced Order Model Of Power System, Ahmet Çi̇fci̇, Yilmaz Uyaroğlu, Mehmet Ali̇ Yalçin

Turkish Journal of Electrical Engineering and Computer Sciences

A power system is a typical nonlinear dynamical system and voltage stability is an important subject of power system stability. This paper describes the use of the variable gradient method in a reduced order model of a single-machine infinite-bus power system. Additionally, the system's Lyapunov (energy) function is created and thus the system's energy level changes' effects on the system's stability are shown using the MACSYMA program. The Lyapunov function allows the determination of stability for nonlinear systems without the need to find exact solutions.

Analysis And Characterization Of Longitudinal Flux Single-Sided Linear Switched Reluctance Machines, Lenin Chokkalingam, Arumugam Rengasamy

Turkish Journal of Electrical Engineering and Computer Sciences

Linear switched reluctance motors (LSRMs) have recently gained more popularity for propulsion drives. This paper contributes a certain design improvement to reduce the force ripple in LSRMs. By affixing a pole cap in the stator pole, the target is achieved. Finite element analysis has been carried out to predict the performance of the basic and proposed structures. Motor performances for different load conditions are simulated. The application of fast Fourier transform has been utilized to envisage the vibration frequencies. The experimental results are well correlated with the predicted results.

Completeness For The Coalgebraic Cover Modality, Clemens Kupke, Alexander Kurz, Yde Venema

Engineering Faculty Articles and Research

We study the finitary version of the coalgebraic logic introduced by L. Moss. The syntax of this logic, which is introduced uniformly with respect to a coalgebraic type functor, required to preserve weak pullbacks, extends that of classical propositional logic with a so-called coalgebraic cover modality depending on the type functor. Its semantics is defined in terms of a categorically defined relation lifting operation.

As the main contributions of our paper we introduce a derivation system, and prove that it provides a sound and complete axiomatization for the collection of coalgebraically valid inequalities. Our soundness and completeness proof is algebraic, …

Coalgebraic Logics (Dagstuhl Seminar 12411), Ernst-Erich Doberkat, Alexander Kurz

Engineering Faculty Articles and Research

This report documents the program and the outcomes of Dagstuhl Seminar 12411 “Coalgebraic Logics”. The seminar deals with recent developments in the area of coalgebraic logic, a branch of logics which combines modal logics with coalgebraic semantics. Modal logic finds its uses when reasoning about behavioural and temporal properties of computation and communication, coalgebras have evolved into a general theory of systems. Consequently, it is natural to combine both areas for a mathematical description of system specification. Coalgebraic logics are closely related to the broader categories semantics/formal methods and verification/logic.

Column: Factors Affecting Data Decay, Kevin Fairbanks, Simson Garfinkel

Journal of Digital Forensics, Security and Law

In nuclear physics, the phrase decay rate is used to denote the rate that atoms and other particles spontaneously decompose. Uranium-235 famously decays into a variety of daughter isotopes including Thorium and Neptunium, which themselves decay to others. Decay rates are widely observed and wildly different depending on many factors, both internal and external. U-235 has a half-life of 703,800,000 years, for example, while free neutrons have a half-life of 611 seconds and neutrons in an atomic nucleus are stable.

Technology Corner Automated Data Extraction Using Facebook, Nick V. Flor

Journal of Digital Forensics, Security and Law

Because of Facebook’s popularity, law enforcement agents often use it as a key source of evidence. But like many user digital trails, there can be a large amount of data to extract for analysis. In this paper, we explore the basics of extracting data programmatically from a user’s Facebook via a Web app. A data extraction app requests data using the Facebook Graph API, and Facebook returns a JSON object containing the data. Before an app can access a user’s Facebook data, the user must log into Facebook and give permission. Thus, this approach is limited to situations where users …

Book Review: Mastering Windows Network Forensics And Investigation, 2/E, John C. Ebert

Journal of Digital Forensics, Security and Law

The book is available as a paperback and e-book. The e-book versions allow you to preview several chapters at any of a number of online vendors. The e-book prices vary from the same as the soft cover version ($59.99) to about $38.99. Some of the vendor's e-books retain the color illustrations found in the print version, but others produce them in grey scale, so you might want to look out for that. The book is divided into four parts (17 chapters) plus two appendices.

I am compelled to give the book illustrations a highly unfavorable assessment regarding their readability qualities. …

Column: Analysis Of Digital Traces, Fred Cohen

Journal of Digital Forensics, Security and Law

In part 1 of this series (Cohen, 2011a), Analysis of digital traces is a foundational process by which the examiner, typically using computer software tools, comes to understand and answer basic questions regarding digital traces.

An Australian Perspective On The Challenges For Computer And Network Security For Novice Endusers, Patryk Szewczyk

Journal of Digital Forensics, Security and Law

It is common for end-users to have difficulty in using computer or network security appropriately and thus have often been ridiculed when misinterpreting instructions or procedures. This discussion paper details the outcomes of research undertaken over the past six years on why security is overly complex for endusers. The results indicate that multiple issues may render end-users vulnerable to security threats and that there is no single solution to address these problems. Studies on a small group of senior citizens has shown that educational seminars can be beneficial in ensuring that simple security aspects are understood and used appropriately.

Automated Identification And Reconstruction Of Youtube Video Access, Jonathan Patterson, Christopher Hargreaves

Journal of Digital Forensics, Security and Law

YouTube is one of the most popular video-sharing websites on the Internet, allowing users to upload, view and share videos with other users all over the world. YouTube contains many different types of videos, from homemade sketches to instructional and educational tutorials, and therefore attracts a wide variety of users with different interests. The majority of YouTube visits are perfectly innocent, but there may be circumstances where YouTube video access is related to a digital investigation, e.g. viewing instructional videos on how to perform potentially unlawful actions or how to make unlawful articles. When a user accesses a YouTube video …

Book Review: System Forensics, Investigation, And Response, Nate Keith

Journal of Digital Forensics, Security and Law

I recently expressed an interest to a respected colleague in finding a way to “give back” to the forensic community. He suggested writing a review for a text he recently received and provide feedback to the community. It is my intent to present an objective analysis of System Forensics, Investigation, and Response.

Identifying Trace Evidence From Target-Specific Data Wiping Application Software, Gregory H. Carlton, Gary C. Kessler

Journal of Digital Forensics, Security and Law

One area of particular concern for computer forensics examiners involves situations in which someone utilized software applications to destroy evidence. There are products available in the marketplace that are relatively inexpensive and advertised as being able to destroy targeted portions of data stored within a computer system. This study was undertaken to analyze a subset of these tools in order to identify trace evidence, if any, left behind on disk media after executing these applications. We evaluated five Windows 7 compatible software products whose advertised features include the ability for users to wipe targeted files, folders, or evidence of selected …

Table Of Contents

Journal of Digital Forensics, Security and Law

No abstract provided.

Technology Corner: A Regular Expression Training App, Nick V. Flor

Journal of Digital Forensics, Security and Law

Regular expressions enable digital forensic analysts to find information in files. The best way for an analyst to become proficient in writing regular expressions is to practice. This paper presents the code for an app that allows an analyst to practice writing regular expressions.

Table Of Contents

Journal of Digital Forensics, Security and Law

No abstract provided.

Extraction Of Electronic Evidence From Voip: Identification & Analysis Of Digital Speech, David Irwin, Arek Dadej, Jill Slay

Journal of Digital Forensics, Security and Law

The Voice over Internet Protocol (VoIP) is increasing in popularity as a cost effective and efficient means of making telephone calls via the Internet. However, VoIP may also be an attractive method of communication to criminals as their true identity may be hidden and voice and video communications are encrypted as they are deployed across the Internet. This produces a new set of challenges for forensic analysts compared with traditional wire-tapping of the Public Switched Telephone Network (PSTN) infrastructure, which is not applicable to VoIP. Therefore, other methods of recovering electronic evidence from VoIP are required. This research investigates the …

Book Review: Dispute Resolution And E-Discovery, Milton Luoma

Journal of Digital Forensics, Security and Law

As is apparent from its title, this book tackles two very current and difficult legal issues – electronic discovery and dispute resolution. The authors tie the two legal concepts together in an effort to provide litigants and practitioners a less expensive and less time consuming alternative than is typically the case with traditional litigation and court proceedings. By including electronic discovery in the discussions, the authors recognize the importance and significance of electronic discovery in mediation and arbitration as it is in traditional litigation.

On The Development Of A Digital Forensics Curriculum, Manghui Tu, Dianxiang Xu, Samsuddin Wira, Cristian Balan, Kyle Cronin

Journal of Digital Forensics, Security and Law

Computer Crime and computer related incidents continue their prevalence and frequency, resulting in losses approaching billions of dollars. To fight against these crimes and frauds, it is urgent to develop digital forensics education programs to train a suitable workforce that can effectively investigate computer crimes and incidents. There is presently no standard to guide the design of digital forensics curriculum for an academic program. In this research, previous work on digital forensics curriculum design and existing education programs are thoroughly investigated. Both digital forensics educators and practitioners were surveyed and results were analyzed to determine the industry and law enforcement …

The Science Of Digital Forensics: Recovery Of Data From Overwritten Areas Of Magnetic Media, Fred Cohen

Journal of Digital Forensics, Security and Law

The first time I encountered data loss and recovery effects of magnetic memory was as a night and weekend computer operator for the computer science department of Carnegie-Mellon University in the 1973-1974 time frame. Part of my job involved dealing directly with outages and failures associated with magnetic memory components used in what, at the time, were large computer systems. On occasions, portions of magnetic core memory or disk drives would encounter various failure modes and the systems using these devices would have to be reconfigured to operate without the failed components until repair personnel could come in to repair …

Automatic Crash Recovery: Internet Explorer's Black Box, John Moran, Douglas Orr

Journal of Digital Forensics, Security and Law

A good portion of today's investigations include, at least in part, an examination of the user's web history. Although it has lost ground over the past several years, Microsoft's Internet Explorer still accounts for a large portion of the web browser market share. Most users are now aware that Internet Explorer will save browsing history, user names, passwords and form history. Consequently some users seek to eliminate these artifacts, leaving behind less evidence for examiners to discover during investigations. However, most users, and probably a good portion of examiners are unaware Automatic Crash Recovery can leave a gold mine of …

Book Review: The Software Ip Detective's Handbook: Measurement, Comparison, And Infringement Detections, Diane Barrett

Journal of Digital Forensics, Security and Law

Do not the book title fool you into thinking that the book is only for those looking to detect software infringement detection. It is a comprehensive look at software intellectual property. The book covers a wide range of topics and has something to offer for just about everyone from lawyers to programmers.

“Preemptive Suppression” – Judges Claim The Right To Find Digital Evidence Inadmissible Before It Is Even Discovered, Bob Simpson

Journal of Digital Forensics, Security and Law

Vermont state prosecutors have asked the Vermont Supreme Court to end a state trial judge’s practice of attaching conditions to computer warrants. The Vermont judge’s conditions are drawn from five conditions established in the 2009 decision of the 9th Circuit Court of Appeals in the Comprehensive Drug Testing, Inc. case (CDT II). This is the first time the validity of the “CDT conditions” will be decided by a state court of final jurisdiction in the United States

Modeling And Control Of Discrete Event Systems Using Finite State Machines With Variables And Their Applications In Power Grids, Junhui Zhao, Le Yi Wang, Zhong Chen, Feng Lin, Hongwei Zhang

Electrical & Computer Engineering and Computer Science Faculty Publications

Control theories for discrete event systems modeled as finite state machines have been well developed to address various fundamental control issues. However, finite state machine model has long suffered from the problem of state explosion that renders it unsuitable for some practical applications. In an attempt to mitigate the state explosion problem, we propose an efficient representation that appends finite sets of variables to finite state machines in modeling discrete event systems. We also present the control synthesis techniques for such finite state machines with variables (FSMwV). We first present our notion and means of control under this representation. We …

A Memory Access Model For Highly-Threaded Many-Core Architectures, Lin Ma, Kunal Agrawal, Roger D. Chamberlain

All Computer Science and Engineering Research

Many-core architectures are excellent in hiding memory-access latency by low-overhead context switching among a large number of threads. The speedup of algorithms carried out on these machines depends on how well the latency is hidden. If the number of threads were infinite, then theoretically these machines should provide the performance predicted by the PRAM analysis of the programs. However, the number of allowable threads per processor is not infinite. In this paper, we introduce the Threaded Many-core Memory (TMM) model which is meant to capture the important characteristics of these highly-threaded, many-core machines. Since we model some important machine parameters …

Foveon F13 Camera, David Shelley

All Computer Science and Engineering Research

Most high-fidelity digital cameras currently available obtain their images using technology where individual pixels can only acquire a single color. Since the acquisition of multiple colors is necessary to capture a full colored image, picture resolution is lost due to difficulties in interpolation between non-adjacent, same color pixels. The resulting unsharp images create the need to find a new way to obtain these images without requiring interpolation between adjacent pixels. An innovative method to capture images with individual pixel cells consisting of three layers of photodetectors stacked vertically upon one another has been created to rectify this problem, but no …