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Articles 4771 - 4800 of 5273

Full-Text Articles in Computer Sciences

An Online Approximator-Based Fault Detection Framework For Nonlinear Discrete-Time Systems, Balaje T. Thumati, Jagannathan Sarangapani Jan 2007

An Online Approximator-Based Fault Detection Framework For Nonlinear Discrete-Time Systems, Balaje T. Thumati, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a fault detection scheme is developed for nonlinear discrete time systems. The changes in the system dynamics due to incipient failures are modeled as a nonlinear function of state and input variables while the time profile of the failures is assumed to be exponentially developing. The fault is detected by monitoring the system and is approximated by using online approximators. A stable adaptation law in discrete-time is developed in order to characterize the faults. The robustness of the diagnosis scheme is shown by extensive mathematical analysis and simulation results.


Route Aware Predictive Congestion Control Protocol For Wireless Sensor Networks, Carl Larsen, Maciej Jan Zawodniok, Jagannathan Sarangapani Jan 2007

Route Aware Predictive Congestion Control Protocol For Wireless Sensor Networks, Carl Larsen, Maciej Jan Zawodniok, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

Congestion in wireless sensor networks (WSN) may lead to packet losses or delayed delivery of important information rendering the WSN-based monitoring or control system useless. In this paper a routing-aware predictive congestion control (RPCC) yet decentralized scheme for WSN is presented that uses a combination of a hop by hop congestion control mechanism to maintain desired level of buffer occupancy, and a dynamic routing scheme that works in concert with the congestion control mechanism to forward the packets through less congested nodes. The proposed adaptive approach restricts the incoming traffic thus preventing buffer overflow while maintaining the rate through an …


Control Of Nonholonomic Mobile Robot Formations: Backstepping Kinematics Into Dynamics, Jagannathan Sarangapani, Travis Alan Dierks Jan 2007

Control Of Nonholonomic Mobile Robot Formations: Backstepping Kinematics Into Dynamics, Jagannathan Sarangapani, Travis Alan Dierks

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we seek to expand framework developed to control a single nonholonomic mobile robot to include the control of formations of multiple nonholonomic mobile robots. A combined kinematic/torque control law is developed for leader-follower based formation control using backstepping in order to accommodate the dynamics of the robots and the formation in contrast with kinematic-based formation controllers. The asymptotic stability of the entire formation is guaranteed using Lyapunov theory, and numerical results are provided The kinematic controller is developed around control strategies for single mobile robots and the idea of virtual leaders. The virtual leader is replaced with …


Neural Network Control Of Robot Formations Using Rise Feedback, Jagannathan Sarangapani, Travis Alan Dierks Jan 2007

Neural Network Control Of Robot Formations Using Rise Feedback, Jagannathan Sarangapani, Travis Alan Dierks

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a combined kinematic/torque control law is developed for leader-follower based formation control using backstepping in order to accommodate the dynamics of the robots and the formation in contrast with kinematic-based formation controllers that are widely reported in the literature. A neural network (NN) is introduced along with robust integral of the sign of the error (RISE) feedback to approximate the dynamics of the follower as well as its leader using online weight tuning. It is shown using Lyapunov theory that the errors for the entire formation are asymptotically stable and the NN weights are bounded as opposed …


Online Reinforcement Learning Control Of Unknown Nonaffine Nonlinear Discrete Time Systems, Qinmin Yang, Jagannathan Sarangapani Jan 2007

Online Reinforcement Learning Control Of Unknown Nonaffine Nonlinear Discrete Time Systems, Qinmin Yang, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel neural network (NN) based online reinforcement learning controller is designed for nonaffine nonlinear discrete-time systems with bounded disturbances. The nonaffine systems are represented by nonlinear auto regressive moving average with exogenous input (NARMAX) model with unknown nonlinear functions. An equivalent affine-like representation for the tracking error dynamics is developed first from the original nonaffine system. Subsequently, a reinforcement learning-based neural network (NN) controller is proposed for the affine-like nonlinear error dynamic system. The control scheme consists of two NNs. One NN is designated as the critic, which approximates a predefined long-term cost function, whereas an …


Online Reinforcement Learning Neural Network Controller Design For Nanomanipulation, Qinmin Yang, Jagannathan Sarangapani Jan 2007

Online Reinforcement Learning Neural Network Controller Design For Nanomanipulation, Qinmin Yang, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel reinforcement learning neural network (NN)-based controller, referred to adaptive critic controller, is proposed for affine nonlinear discrete-time systems with applications to nanomanipulation. In the online NN reinforcement learning method, one NN is designated as the critic NN, which approximates the long-term cost function by assuming that the states of the nonlinear systems is available for measurement. An action NN is employed to derive an optimal control signal to track a desired system trajectory while minimizing the cost function. Online updating weight tuning schemes for these two NNs are also derived. By using the Lyapunov approach, …


Optimal Location For Shunt Connected Facts Devices In A Series Compensated Long Transmission Line, P.R. Sharma, Ashok Kumar, Narender Kumar Jan 2007

Optimal Location For Shunt Connected Facts Devices In A Series Compensated Long Transmission Line, P.R. Sharma, Ashok Kumar, Narender Kumar

Turkish Journal of Electrical Engineering and Computer Sciences

Shunt FACTS devices are used for controlling transmission voltage, power flow, reducing reactive losses, and damping of power system oscillations for high power transfer levels. In this paper the optimal location of a shunt FACT device is investigated for an actual line model of a transmission line having series compensation at the center. Effect of change in degree of series compensation on the optimal location of the shunt FACTS device to get the highest possible benefit is studied. It is found that the optimal location of the shunt FACTS device varies with the change in the level of series compensation …


A Grounded Theory Approach To Identifying And Measuring Forensic Data Acquisition Tasks, Gregory H. Carlton Jan 2007

A Grounded Theory Approach To Identifying And Measuring Forensic Data Acquisition Tasks, Gregory H. Carlton

Journal of Digital Forensics, Security and Law

As a relatively new field of study, little empirical research has been conducted pertaining to computer forensics. This lack of empirical research contributes to problems for practitioners and academics alike.

For the community of practitioners, problems arise from the dilemma of applying scientific methods to legal matters based on anecdotal training methods, and the academic community is hampered by a lack of theory in this evolving field. A research study utilizing a multi-method approach to identify and measure tasks practitioners perform during forensic data acquisitions and lay a foundation for academic theory development was conducted in 2006 in conjunction with …


Information Governance: A Model For Security In Medical Practice, Patricia A. Williams Jan 2007

Information Governance: A Model For Security In Medical Practice, Patricia A. Williams

Journal of Digital Forensics, Security and Law

Information governance is becoming an important aspect of organisational accountability. In consideration that information is an integral asset of most organisations, the protection of this asset will increasingly rely on organisational capabilities in security. In the medical arena this information is primarily sensitive patient-based information. Previous research has shown that application of security measures is a low priority for primary care medical practice and that awareness of the risks are seriously underestimated. Consequently, information security governance will be a key issue for medical practice in the future. Information security governance is a relatively new term and there is little existing …


Book Review: Conquest In Cyberspace: National Security And Information Warfare, Gary C. Kessler Jan 2007

Book Review: Conquest In Cyberspace: National Security And Information Warfare, Gary C. Kessler

Journal of Digital Forensics, Security and Law

This is the Book Review column for the JDFSL. It is an experiment to broaden the services that the journal provides to readers, so we are anxious to get your reaction. Is the column useful and interesting? Should we include more than one review per issue? Should we also review products? Do you have suggested books/products for review and/or do you want to write a review? All of this type of feedback -- and more -- is appreciated. Please feel free to send comments to Gary Kessler ([email protected]) or Glenn Dardick ([email protected]).


Information Technology Act 2000 In India - Authentication Of E-Documents, R. G. Pawar, B. S. Sawant, A. Kaiwade Jan 2007

Information Technology Act 2000 In India - Authentication Of E-Documents, R. G. Pawar, B. S. Sawant, A. Kaiwade

Journal of Digital Forensics, Security and Law

The Information Technology Act 2000 has enacted in India on 9th June 2000. This Act has mentioned provision of authentication of electronic document. It is the need of hour at that time that such provision is needed in the Indian Law system, especially for electronic commerce and electronic governance. Electronic commerce”, which involve the use of alternatives to paper based methods of communication and storage information. To do electronic commerce there should be authentication of particular document. The working of internet is the documents are traveling in terms of bits from one destination to other destination, through various media like …


Monitoring And Surveillance In The Workplace: Lessons Learnt? – Investigating The International Legal Position, Verine Etsebeth Jan 2007

Monitoring And Surveillance In The Workplace: Lessons Learnt? – Investigating The International Legal Position, Verine Etsebeth

Journal of Digital Forensics, Security and Law

When considering the legal implications of monitoring and surveillance in the workplace, the question may be asked why companies deploy computer surveillance and monitoring in the first place. Several reasons may be put forward to justify why more than 80% of all major American firms monitor employee e-mails and Internet usage. However, what most companies forget is the fact that the absence or presence of monitoring and surveillance activities in a company holds serious legal consequences for companies. From the discussion in this paper it will become apparent that there is a vast difference in how most countries approach this …


Education Organization Baseline Control Protection And Trusted Level Security, Wasim A. Al-Hamdani Jan 2007

Education Organization Baseline Control Protection And Trusted Level Security, Wasim A. Al-Hamdani

Journal of Digital Forensics, Security and Law

Many education organizations have adopted for security the enterprise best practices for implementation on their campuses, while others focus on ISO Standard (or/and) the National Institution of Standards and Technology.

All these adoptions are dependent on IT personal and their experiences or knowledge of the standard. On top of this is the size of the education organizations. The larger the population in an education organization, the more the problem of information and security become very clear. Thus, they have been obliged to comply with information security issues and adopt the national or international standard. The case is quite different when …


Network And Database Security: Regulatory Compliance, Network, And Database Security - A Unified Process And Goal, Errol A. Blake Jan 2007

Network And Database Security: Regulatory Compliance, Network, And Database Security - A Unified Process And Goal, Errol A. Blake

Journal of Digital Forensics, Security and Law

Database security has evolved; data security professionals have developed numerous techniques and approaches to assure data confidentiality, integrity, and availability. This paper will show that the Traditional Database Security, which has focused primarily on creating user accounts and managing user privileges to database objects are not enough to protect data confidentiality, integrity, and availability. This paper is a compilation of different journals, articles and classroom discussions will focus on unifying the process of securing data or information whether it is in use, in storage or being transmitted. Promoting a change in Database Curriculum Development trends may also play a role …


Book Review: No Place To Hide, Gary C. Kessler Jan 2007

Book Review: No Place To Hide, Gary C. Kessler

Journal of Digital Forensics, Security and Law

This issue presents the second Book Review column for the JDFSL. It is an experiment to broaden the services that the journal provides to readers, so we are anxious to get your reaction. Is the column useful and interesting? Should we include more than one review per issue? Should we also review products? Do you have suggested books/products for review and/or do you want to write a review? All of this type of feedback -- and more -- is appreciated. Please feel free to send comments to Gary Kessler ([email protected]) or Glenn Dardick ([email protected]).


The Evolution Of Internet Legal Regulation In Addressing Crime And Terrorism, Murdoch Watney Jan 2007

The Evolution Of Internet Legal Regulation In Addressing Crime And Terrorism, Murdoch Watney

Journal of Digital Forensics, Security and Law

Internet regulation has evolved from self-regulation to the criminalization of conduct to state control of information available, accessed and submitted. Criticism has been leveled at the different forms of state control and the methods employed to enforce state control. After the terrorist attack on the USA on 11 September 2001, governments justify Internet state control as a law enforcement and national security tool against the abuse and misuse of the Internet for the commission of serious crimes, such as phishing, child pornography; terrorism and copyright infringement. Some Internet users and civil rights groups perceive state control as an abomination which …


Computer Crimes: A Case Study Of What Malaysia Can Learn From Others?, Janaletchumi Appudurai, Chitra L. Ramalingam Jan 2007

Computer Crimes: A Case Study Of What Malaysia Can Learn From Others?, Janaletchumi Appudurai, Chitra L. Ramalingam

Journal of Digital Forensics, Security and Law

Rapid development of information technology (IT) has brought with it many new applications such as e-commerce and global business. The past few years have seen activities in the legislative arena covering issues such as digital signatures, the international recognition of electronic documents and privacy and data protection. Both the developed and developing countries have exhibited keenness to embrace the IT environment. Securing this electronic environment from intrusion, however, continues to be problematic. A particular favorite form of computer crime would be ‘hacking’. As more computer systems move on to on-line processing and improved telecommunications, computer hackers are now a real …


Near Optimal Output-Feedback Control Of Nonlinear Discrete-Time Systems In Nonstrict Feedback Form With Application To Engines, Peter Shih, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier Jan 2007

Near Optimal Output-Feedback Control Of Nonlinear Discrete-Time Systems In Nonstrict Feedback Form With Application To Engines, Peter Shih, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier

Electrical and Computer Engineering Faculty Research & Creative Works

A novel reinforcement-learning based output-adaptive neural network (NN) controller, also referred as the adaptive-critic NN controller, is developed to track a desired trajectory for a class of complex nonlinear discrete-time systems in the presence of bounded and unknown disturbances. The controller includes an observer for estimating states and the outputs, critic, and two action NNs for generating virtual, and actual control inputs. The critic approximates certain strategic utility function and the action NNs are used to minimize both the strategic utility function and their outputs. All NN weights adapt online towards minimization of a performance index, utilizing gradient-descent based rule. …


Reinforcement Learning Neural-Network-Based Controller For Nonlinear Discrete-Time Systems With Input Constraints, Pingan He, Jagannathan Sarangapani Jan 2007

Reinforcement Learning Neural-Network-Based Controller For Nonlinear Discrete-Time Systems With Input Constraints, Pingan He, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

A novel adaptive-critic-based neural network (NN) controller in discrete time is designed to deliver a desired tracking performance for a class of nonlinear systems in the presence of actuator constraints. The constraints of the actuator are treated in the controller design as the saturation nonlinearity. The adaptive critic NN controller architecture based on state feedback includes two NNs: the critic NN is used to approximate the "strategic" utility function, whereas the action NN is employed to minimize both the strategic utility function and the unknown nonlinear dynamic estimation errors. The critic and action NN weight updates are derived by minimizing …


Adaptive Power Control Protocol With Hardware Implementation For Wireless Sensor And Rfid Reader Networks, Kainan Cha, Jagannathan Sarangapani, David Pommerenke Jan 2007

Adaptive Power Control Protocol With Hardware Implementation For Wireless Sensor And Rfid Reader Networks, Kainan Cha, Jagannathan Sarangapani, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

The development and deployment of radio frequency identification (RFID) systems render a novel distributed sensor network which enhances visibility into manufacturing processes. In RFID systems, the detection range and read rates will suffer from interference among high-power reading devices. This problem grows severely and degrades system performance in dense RFID networks. Consequently, medium access protocols (MAC) protocols are needed for such networks to assess and provide access to the channel so that tags can be read accurately. In this paper, we investigate a suite of feasible power control schemes to ensure overall coverage area of the system while maintaining a …


Adaptive Neural Network Based Stabilizing Controller Design For Single Machine Infinite Bus Power Systems, Wenxin Liu, Ganesh K. Venayagamoorthy, Donald C. Wunsch, David A. Cartes, Jagannathan Sarangapani, Mariesa Crow Jan 2007

Adaptive Neural Network Based Stabilizing Controller Design For Single Machine Infinite Bus Power Systems, Wenxin Liu, Ganesh K. Venayagamoorthy, Donald C. Wunsch, David A. Cartes, Jagannathan Sarangapani, Mariesa Crow

Engineering Management and Systems Engineering Faculty Research & Creative Works

Power system stabilizers are widely used to generate supplementary control signals for the excitation system in order to damp out the low frequency oscillations. In power system control literature, the performances of the proposed controllers were mostly demonstrated using simulation results without any rigorous stability analysis. This paper proposes a stabilizing neural network (NN) controller based on a sixth order single machine infinite bus power system model. The NN is used to approximate the complex nonlinear dynamics of power system. Unlike the other indirect adaptive NN control schemes, there is no offline training process and the NN can be directly …


Opensourcepacs: An Extensible Infrastructure For Medical Image Management, John David N. Dionisio, Alex A T Bui, Craig Morioka, David B. Johnson, Usha Sinha, Siamak Ardekani, Ricky K. Taira, Denise R. Aberle, Suzie El-Saden, Hooshang Kangarloo Jan 2007

Opensourcepacs: An Extensible Infrastructure For Medical Image Management, John David N. Dionisio, Alex A T Bui, Craig Morioka, David B. Johnson, Usha Sinha, Siamak Ardekani, Ricky K. Taira, Denise R. Aberle, Suzie El-Saden, Hooshang Kangarloo

Computer Science Faculty Works

The development of comprehensive picture archive and communication systems (PACS) has mainly been limited to proprietary developments by vendors, though a number of freely available software projects have addressed specific image management tasks. The openSourcePACS project aims to provide an open source, common foundation upon which not only can a basic PACS be readily implemented, but to also support the evolution of new PACS functionality through the development of novel imaging applications and services. openSourcePACS consists of four main software modules: 1) image order entry, which enables the ordering and tracking of structured image requisitions; 2) an agent-based image server …


A Variable Gain Pi Controller Used For Speed Control Of A Direct Torque Neuro Fuzzy Controlled Induction Machine Drive, A. Miloudi, Eid A. Al-Radadi, Azeddine Draou Jan 2007

A Variable Gain Pi Controller Used For Speed Control Of A Direct Torque Neuro Fuzzy Controlled Induction Machine Drive, A. Miloudi, Eid A. Al-Radadi, Azeddine Draou

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents an original variable gain PI (VGPI) controller for speed control of a direct torque neuro fuzzy controlled (DTNFC) induction motor drive. First, a VGPI speed controller is designed to replace the classical PI controller in a conventional direct torque controlled induction motor drive. Its simulated performances are then compared to those of a classical PI controller. Then, a direct torque neuro fuzzy control (DTNFC) for a voltage source PWM inverter fed induction motor drive is presented. This control scheme uses the stator flux amplitude and the electromagnetic torque errors through an adaptive NF inference system (ANFIS) to …


Analysis Of Finline Structures With Consideration Of Metallization Thickness And Substrate Mounting Grooves, Abderrahmane Ouadi, Hadj Bourdoucen Jan 2007

Analysis Of Finline Structures With Consideration Of Metallization Thickness And Substrate Mounting Grooves, Abderrahmane Ouadi, Hadj Bourdoucen

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, mathematical analysis and numerical calculations of main parameters of finline structures with finite metallization thickness and substrate mounting grooves are developed based on the Method of Lines (MoL). The results obtained provide confirmation of the validity of the technique used and prove its simplicity and adequacy for treating different types of planar structures mainly finline based structures. Unilateral and bilateral finlines including practical parameters, such as metallization thickness and grooves' depths, have been investigated. The effect of these two parameters have been discussed based on realistic configurations and the results show that, at higher frequencies, the grooves …


A Critical Review On Electromagnetic Precursors And Earthquake Prediction, Levent Sevgi̇ Jan 2007

A Critical Review On Electromagnetic Precursors And Earthquake Prediction, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

Seismo-electromagnetic precursory-based earthquake prediction studies are criticized in terms of their scientific content, problem complexity, signal excitation and propagation, causal relations with earthquakes, and public awareness and expectations. One aim is to trigger a new debate on this hot topic in the Electromagnetic Society.


New Method For Investigation Of Dynamic Parameters Of Thermoelectric Modules, Raşi̇t Ahiska Jan 2007

New Method For Investigation Of Dynamic Parameters Of Thermoelectric Modules, Raşi̇t Ahiska

Turkish Journal of Electrical Engineering and Computer Sciences

Precise calculation of parameters of thermoelectric modules and thermoelectric devices under operating conditions by present methods is very difficult. In this study, a new method is developed to calculate all parameters of thermoelectric modules. This new method makes it possible to determine the dynamic parameters of a real thermoelectric module operated under different working regimes. Measurement of thermoemf created by an operating module is the basis of this new method. An unloaded thermoelectric module, whose dynamic output parameters are necessary in the design of a medical helmet for the cooling of brain, has been investigated using this new method. A …


Data Mining And Costas Arrays, Konstantinos Drakakis Jan 2007

Data Mining And Costas Arrays, Konstantinos Drakakis

Turkish Journal of Electrical Engineering and Computer Sciences

Costas arrays are used in RADAR (and SONAR) engineering to represent frequency-hopping patterns that optimize the RADAR's performance. In this work, using all available Costas arrays up to and including order 26, as well as data mining techniques, we investigate how the Costas property and the balance of signs in the difference triangle of a permutation are related. Our conclusion is that there is sufficient evidence to believe that the mechanism responsible for the formation of Costas arrays changes from low to high orders.


Offline Signature Verification Using Graph Matching, Ibrahim S. I. Abuhaiba Jan 2007

Offline Signature Verification Using Graph Matching, Ibrahim S. I. Abuhaiba

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we present a simple and effective signature verification method that depends only on the raw binary pixel intensities and avoids using complex sets of features. The method looks at the signature verification problem as a graph matching problem. The method is tested using genuine and forgery signatures produced by five subjects. An equal error rate of 26.7% and 5.6% was achieved for skilled and random forgeries, respectively. A positive property of our algorithm is that the false acceptance rate of random forgeries vanishes at the point of equal false rejection and skilled forgery false acceptance rates. Keeping …


Umts-Hsdpa In High Altitude Platforms (Haps) Communications, Bazil Taha Ahmed, Miguel Calvo Ramon, Leandro De Haro-Ariet Jan 2007

Umts-Hsdpa In High Altitude Platforms (Haps) Communications, Bazil Taha Ahmed, Miguel Calvo Ramon, Leandro De Haro-Ariet

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the performance of HAPs (High Altitudes Platforms) UMTS HSDPA (High Speed Downlink Packet Access) is studied for different HAPs height h, different cells radius R and two directions (0° and 30°) within the cell. The network under study is assumed to have 61 ground cells. It is noticed that, for urban zone users, the effective range is lower than the effective range for users in rural zones for a given modulation scheme. Also it is noticed that in rural zone, the HSDPA can support higher modulation schemes. It is noticed that, when 80% of the base station …


A Review Of Studies In Swarm Robotics, Levent Bayindir, Erol Şahi̇n Jan 2007

A Review Of Studies In Swarm Robotics, Levent Bayindir, Erol Şahi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

Swarm robotics is a new approach to the coordination of large numbers of relatively simple robots. The approach takes its inspiration from the system-level functioning of social insects which demonstrate three desired characteristics for multi-robot systems: robustness, flexibility and scalability. In this paper we have presented a preliminary taxonomy for swarm robotics and classified existing studies into this taxonomy after investigating the existing surveys related to swarm robotics literature. Our parent taxonomic units are modeling, behavior design, communication, analytical studies and problems. We are classifying existing studies into these main axes. Since existing reviews do not have enough number of …