Open Access. Powered by Scholars. Published by Universities.®

Computer Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

Missouri University of Science and Technology

Discipline
Keyword
Publication Year
Publication
Publication Type

Articles 1351 - 1380 of 1938

Full-Text Articles in Computer Sciences

Comparisons Of An Adaptive Neural Network Based Controller And An Optimized Conventional Power System Stabilizer, Wenxin Liu, Ganesh K. Venayagamoorthy, Jagannathan Sarangapani, Donald C. Wunsch, Mariesa Crow, Li Liu, David A. Cartes Oct 2007

Comparisons Of An Adaptive Neural Network Based Controller And An Optimized Conventional Power System Stabilizer, Wenxin Liu, Ganesh K. Venayagamoorthy, Jagannathan Sarangapani, Donald C. Wunsch, Mariesa Crow, Li Liu, David A. Cartes

Electrical and Computer Engineering Faculty Research & Creative Works

Power system stabilizers are widely used to damp out the low frequency oscillations in power systems. In power system control literature, there is a lack of stability analysis for proposed controller designs. This paper proposes a Neural Network (NN) based stabilizing controller design based on a sixth order single machine infinite bus power system model. The NN is used to compensate the complex nonlinear dynamics of power system. To speed up the learning process, an adaptive signal is introduced to the NN's weights updating rule. The NN can be directly used online without offline training process. Magnitude constraint of the …

Go to article

Use Of Max-Flow On Facts Devices, Adam Lininger, Bruce M. Mcmillin, Badrul H. Chowdhury, Mariesa Crow Oct 2007

Use Of Max-Flow On Facts Devices, Adam Lininger, Bruce M. Mcmillin, Badrul H. Chowdhury, Mariesa Crow

Computer Science Faculty Research & Creative Works

FACTS devices can be used to mitigate cascading failures in a power grid by controlling the power flow in individual lines. Placement and control are significant issues. We present a procedure for determining whether a scenario can be mitigated using the concept of maximum flow. If it can be mitigated, we determine what placement and control setting will solve the scenario. This paper treats fourteen cascading failure scenarios and reports on the use of the max-flow algorithm both in determining the mitigation of each scenario and in finding FACTS settings that will mitigate the scenario.

Go to article

Energy-Efficient Hybrid Key Management Protocol For Wireless Sensor Networks, Timothy J. Landstra, Maciej Jan Zawodniok, Jagannathan Sarangapani Oct 2007

Energy-Efficient Hybrid Key Management Protocol For Wireless Sensor Networks, Timothy J. Landstra, Maciej Jan Zawodniok, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we propose a subnetwork key management strategy in which the heterogeneous security requirements of a wireless sensor network are considered to provide differing levels of security with minimum communication overhead. Additionally, it allows the dynamic creation of high security subnetworks within the wireless sensor network and provides subnetworks with a mechanism for dynamically creating a secure key using a novel and dynamic group key management protocol. The proposed energy-efficient protocol utilizes a combination of pre-deployed group keys and initial trustworthiness of nodes to create a level of trust between neighbors in the network. This trust is later …

Go to article

Control Of Nonholonomic Mobile Robot Formations Using Neural Networks, Jagannathan Sarangapani, Travis Alan Dierks Oct 2007

Control Of Nonholonomic Mobile Robot Formations Using Neural Networks, Jagannathan Sarangapani, Travis Alan Dierks

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper the control of formations of multiple nonholonomic mobile robots is attempted by integrating a kinematic controller with a neural network (NN) computed-torque controller. 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 NN is introduced 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 uniformly ultimately bounded, and numerical results are provided.

Go to article

Neural Network Based Decentralized Controls Of Large Scale Power Systems, Wenxin Liu, Jagannathan Sarangapani, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Mariesa Crow, Li Liu, David A. Cartes Oct 2007

Neural Network Based Decentralized Controls Of Large Scale Power Systems, Wenxin Liu, Jagannathan Sarangapani, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Mariesa Crow, Li Liu, David A. Cartes

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a suite of neural network (NN) based decentralized controller designs for large scale power systems' generators, one is for the excitation control and the other is for the steam valve control. Though the control inputs are calculated using local signals, the transient and overall system stability can be guaranteed. NNs are used to approximate the unknown and/or imprecise dynamics of the local power system dynamics and the inter-connection terms, thus the requirements for exact system parameters are relaxed. Simulation studies with a three-machine power system demonstrate the effectiveness of the proposed controller designs.

Go to article

Blueprint For Iteratively Hardening Power Grids Employing Unified Power Flow Controllers, William M. Siever, Ann K. Miller, Daniel R. Tauritz Sep 2007

Blueprint For Iteratively Hardening Power Grids Employing Unified Power Flow Controllers, William M. Siever, Ann K. Miller, Daniel R. Tauritz

Electrical and Computer Engineering Faculty Research & Creative Works

A stable electricity supply is vital for modern society. However, many parts of our power transmission grid are operating near their operational limits. Such stressed systems are vulnerable to cascading failures, where a few small faults can induce a cascade of failures potentially leading to a major blackout The unified power flow controller (UPFC), the most powerful highspeed, semi-conductor based power flow device, can be used as a theoretical model to study how these devices can be used to improve power grid resilience. The blueprint presented here can be used to iteratively identify critical weaknesses in power grids and to …

Go to article

Toward Automating Ea Configuration: The Parent Selection Stage, Ekaterina Smorodkina, Daniel R. Tauritz Sep 2007

Toward Automating Ea Configuration: The Parent Selection Stage, Ekaterina Smorodkina, Daniel R. Tauritz

Computer Science Faculty Research & Creative Works

One of the obstacles to Evolutionary Algorithms (EAs) fulfilling their promise as easy to use general-purpose problem solvers, is the difficulty of correctly configuring them for specific problems such as to obtain satisfactory performance. Having a mechanism for automatically configuring parameters and operators of every stage of the evolutionary life-cycle would give EAs a more widely spread popularity in the non-expert community. This paper investigates automatic configuration of one of the stages of the evolutionary life-cycle, the parent selection, via a new concept of semi-autonomous parent selection, where mate selection operators are encoded and evolved as in Genetic Programming. We …

Go to article

Reliability Modeling For The Advanced Electric Power Grid, Ayman Z. Faza, Sahra Sedigh, Bruce M. Mcmillin Sep 2007

Reliability Modeling For The Advanced Electric Power Grid, Ayman Z. Faza, Sahra Sedigh, Bruce M. Mcmillin

Electrical and Computer Engineering Faculty Research & Creative Works

The advanced electric power grid promises a self-healing infrastructure using distributed, coordinated, power electronics control. One promising power electronics device, the Flexible AC Transmission System (FACTS), can modify power flow locally within a grid. Embedded computers within the FACTS devices, along with the links connecting them, form a communication and control network that can dynamically change the power grid to achieve higher dependability. The goal is to reroute power in the event of transmission line failure. Such a system, over a widespread area, is a cyber-physical system. The overall reliability of the grid is a function of the respective reliabilities …

Go to article

Risk Assessment In Early Software Design Based On The Software Function-Failure Design Method, Jayson P. Vucovich, Robert B. Stone, Xiaoqing Frank Liu, Irem Y. Tumer Aug 2007

Risk Assessment In Early Software Design Based On The Software Function-Failure Design Method, Jayson P. Vucovich, Robert B. Stone, Xiaoqing Frank Liu, Irem Y. Tumer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Potential software failures present a sizable risk element in the design and development of many systems. In this paper, we augment the Software Function-Failure Design method, which is capable of predicting potential software failures in the very early stages of design, with the Risk in Early Design technique. This synergistic combination allows a risk assessment to be conducted at an early time in the software development process when traditional techniques are not applicable. The results are concise risk statements regarding the potential failure of functionalities with likelihood and consequence quantifications that can be used as part of a risk management …

Go to article

A Supply Chain Design Model With Unreliable Supply, Lian Qi, Zuo-Jun Max Shen Aug 2007

A Supply Chain Design Model With Unreliable Supply, Lian Qi, Zuo-Jun Max Shen

Business and Information Technology Faculty Research & Creative Works

Uncertainties abound within a supply chain and have big impacts on its performance. We propose an integrated model for a three-tiered supply chain network with one supplier, one or more facilities and retailers. This model takes into consideration the unreliable aspects of a supply chain. the properties of the optimal solution to the model are analyzed to reveal the impacts of supply uncertainty on supply chain design decisions. We also propose a general solution algorithm for this model. Computational experience is presented and discussed.

Go to article

Infrastructure Hardening: A Competitive Co-Evolutionary Methodology Inspired By Neo-Darwinian Arms Races, Travis Service, Daniel R. Tauritz, William M. Siever Jul 2007

Infrastructure Hardening: A Competitive Co-Evolutionary Methodology Inspired By Neo-Darwinian Arms Races, Travis Service, Daniel R. Tauritz, William M. Siever

Computer Science Faculty Research & Creative Works

The world is increasingly dependent on critical infrastructures such as the electric power grid, water, gas, and oil transport systems, which are susceptible to cascading failures that can result from a few faults. Due to the combinatorial complexity in the search spaces involved, most traditional search techniques are inappropriate for identifying these faults and potential protections against them. This paper provides a computational methodology employing competitive coevolution to simultaneously identify low-effort, high-impact faults and corresponding means of hardening infrastructures against them. A power system case study provides empirical evidence that our proposed methodology is capable of identifying cost effective modifications …

Go to article

Specification Of Non-Functional Requirements For Contract Specification In The Ngoss Framework For Quality Management And Product Evaluation, Manooch Amoozdeh, Nektarios Georgalas, Xiaoqing Frank Liu Jul 2007

Specification Of Non-Functional Requirements For Contract Specification In The Ngoss Framework For Quality Management And Product Evaluation, Manooch Amoozdeh, Nektarios Georgalas, Xiaoqing Frank Liu

Computer Science Faculty Research & Creative Works

The community of operation support systems (OSS) for telecom applications defined a set of fundamental principles, processes, and architectures for developing the next generation OSS through the TeleManagement Forum TMF. At the heart of NGOSS lies the notion of a "contract" which embodies the specification of services offered by an OSS component for quality management and product evaluation. However, TMF does not provide any method (or process) for specification of the non-functional part in the NGOSS contract specification. In this paper, we develop a systematic approach for specifying non-functional requirements of telecom OSS applications for contracts in the NGOSS framework …

Go to article

Online Reinforcement Learning-Based Neural Network Controller Design For Affine Nonlinear Discrete-Time Systems, Qinmin Yang, Jagannathan Sarangapani Jul 2007

Online Reinforcement Learning-Based Neural Network Controller Design For Affine Nonlinear Discrete-Time Systems, 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 general multi-input and multi- output affine unknown nonlinear discrete-time systems in the presence of bounded disturbances. Adaptive critic designs consist of two entities, an action network that produces optimal solution and a critic that evaluates the performance of the action network. The critic is termed adaptive as it adapts itself to output the optimal cost-to-go function and the action network is adapted simultaneously based on the information from the critic. In our online learning method, one NN is designated as the …

Go to article

Reinforcement Learning Based Output-Feedback Control Of Nonlinear Nonstrict Feedback Discrete-Time Systems With Application To Engines, Peter Shih, Jonathan B. Vance, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier Jul 2007

Reinforcement Learning Based Output-Feedback Control Of Nonlinear Nonstrict Feedback Discrete-Time Systems With Application To Engines, Peter Shih, Jonathan B. Vance, 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. …

Go to article

Survey Of Supercomputer Cluster Security Issues, George Markowsky, Linda Markowsky Jun 2007

Survey Of Supercomputer Cluster Security Issues, George Markowsky, Linda Markowsky

Computer Science Faculty Research & Creative Works

The authors believe that providing security for supercomputer clusters is different from providing security for stand-alone PCs. The types of programs that supercomputer clusters run and the sort of data available on supercomputer clusters are fundamentally different from the programs and data found on stand-alone PCs. This situation might attract a different type of attacker with different goals and different tactics. This paper discusses the results of a questionnaire sent out to many supercomputer clusters in the United States and relates them to a literature search that was also undertaken. These results suggest approaches that can be taken to further …

Go to article

Incorporating Inventory And Routing Costs In Strategic Location Models, Zuo-Jun Max Shen, Lian Qi Jun 2007

Incorporating Inventory And Routing Costs In Strategic Location Models, Zuo-Jun Max Shen, Lian Qi

Business and Information Technology Faculty Research & Creative Works

We consider a supply chain design problem where the decision maker needs to decide the number and previous termlocationsnext term of the distribution centers (DCs). Customers face random demand, and each DC maintains a certain amount of safety stock in order to achieve a certain service level for the customers it serves. The objective is to minimize the total previous termcostnext term that includes previous termlocation costs and inventory costsnext term at the DCs, and distribution previous termcostsnext term in the supply chain. We show that this problem can be formulated as a nonlinear integer programming previous termmodel,next term for …

Go to article

The Impact Of Cultural And Religious Values On Adoption Of Innovation, Angela Hausman, Morris Kalliny Jun 2007

The Impact Of Cultural And Religious Values On Adoption Of Innovation, Angela Hausman, Morris Kalliny

Business and Information Technology Faculty Research & Creative Works

Although managing the adoption of innovations domestically can be frustrating, the complexity of the issue increases tremendously when companies take a global approach to marketing. Differences in cultural and religious values can have a great impact on the process of innovation adoption. This study investigates the role of these cultural and religious values, specifically, collectivism/individualism/, uncertainty avoidance and power distance. a conceptual model is presented to illustrate the relationship between cultural/religious values and adoption of innovation.

Go to article

Conquer: A Peer Group-Based Incentive Model For Constraint Querying In Mobile-P2p Networks, Anirban Mondal, Sanjay Kumar Madria, Masaru Kitsuregawa May 2007

Conquer: A Peer Group-Based Incentive Model For Constraint Querying In Mobile-P2p Networks, Anirban Mondal, Sanjay Kumar Madria, Masaru Kitsuregawa

Computer Science Faculty Research & Creative Works

In mobile ad-hoc peer-to-peer (M-P2P) networks, economic models become a necessity for enticing non-cooperative mobile peers to provide service. M-P2P users may issue queries with varying constraints on query response time, data quality of results and trustworthiness of the data source. This work proposes ConQuer, which addresses constraint queries in economybased M-P2P networks. ConQuer proposes a broker-based incentive M-P2P model for handling user-defined constraint queries. It also provides incentives for MPs to form collaborative peer groups for maximizing data availability and revenues by mutually allocating and deallocating data items using a royalty-based revenue-sharing method. Such reallocations facilitate MPs in providing …

Go to article

Management Of An Intelligent Argumentation Network For A Web-Based Collaborative Engineering Design Environment, Xiaoqing Frank Liu, Man Zheng, Ganesh K. Venayagamoorthy, Ming-Chuan Leu May 2007

Management Of An Intelligent Argumentation Network For A Web-Based Collaborative Engineering Design Environment, Xiaoqing Frank Liu, Man Zheng, Ganesh K. Venayagamoorthy, Ming-Chuan Leu

Computer Science Faculty Research & Creative Works

Conflict resolution is one of the most challenging tasks in collaborative engineering design. In our previous research, a web-based intelligent collaborative system was developed to address this challenge based on intelligent computational argumentation. However, two important issues were not resolved in that system: priority of participants and self-conflicting arguments. In this paper, we develop two methods for incorporating priorities of participants into the computational argumentation network: 1) weighted summation and 2) re-assessment of strengths of arguments based on priority of owners of the argument using fuzzy logic inference. In addition, we develop a method for detection of self-conflicting arguments. Incorporation …

Go to article

Energy-Efficient Group Key Management Protocols For Hierarchical Sensor Networks, Biswajit Panja, Sanjay Kumar Madria, Bharat Bhargava Apr 2007

Energy-Efficient Group Key Management Protocols For Hierarchical Sensor Networks, Biswajit Panja, Sanjay Kumar Madria, Bharat Bhargava

Computer Science Faculty Research & Creative Works

In this paper, we describe a group key management protocol for hierarchical sensor networks where instead of using pre-deployed keys, each sensor node generates a partial key dynamically using a function. The function takes partial keys of its children as arguments. The design of the protocol is motivated by the fact that traditional cryptographic techniques are impractical in sensor networks because of associated high energy and computational overheads. The group key management protocol supports the establishment of two types of group keys; one for the nodes within a group (intra-cluster), and the other among a group of cluster heads (inter-cluster). …

Go to article

An Automatically Tuning Intrusion Detection System, Zhenwei Yu, Jeffrey J.-P. Tsai, Thomas Weigert Apr 2007

An Automatically Tuning Intrusion Detection System, Zhenwei Yu, Jeffrey J.-P. Tsai, Thomas Weigert

Computer Science Faculty Research & Creative Works

An intrusion detection system (IDS) is a security layer used to detect ongoing intrusive activities in information systems. Traditionally, intrusion detection relies on extensive knowledge of security experts, in particular, on their familiarity with the computer system to be protected. To reduce this dependence, various data-mining and machine learning techniques have been deployed for intrusion detection. An IDS is usually working in a dynamically changing environment, which forces continuous tuning of the intrusion detection model, in order to maintain sufficient performance. The manual tuning process required by current systems depends on the system operators in working out the tuning solution …

Go to article

Verifying Noninterference In A Cyber-Physical System The Advanced Electric Power Grid, David Cape, Xiaoqing Frank Liu, Bruce M. Mcmillin, Yan Sun Jan 2007

Verifying Noninterference In A Cyber-Physical System The Advanced Electric Power Grid, David Cape, Xiaoqing Frank Liu, Bruce M. Mcmillin, Yan Sun

Computer Science Faculty Research & Creative Works

The advanced electric power grid is a complex real-time system having both cyber and physical components. While each component may function correctly, independently, their composition may yield incorrectness due to interference. One specific type of interference is in the frequency domain, essentially, violations of the Nyquist rate. The challenge is to encode these signal processing problem characteristics into a form that can be model checked. To verify the correctness of the cyber-physical composition using model-checking techniques requires that a model be constructed that can represent frequency interference. In this paper, RT-PROMELA was used to construct the model, which was checked …

Go to article

Improving The Usability Of Evolutionary Algorithms: Self-Adaptive Semi-Autonomous Democratic Parent Selection, Joshua M. Eads Jan 2007

Improving The Usability Of Evolutionary Algorithms: Self-Adaptive Semi-Autonomous Democratic Parent Selection, Joshua M. Eads

Opportunities for Undergraduate Research Experience Program (OURE)

One of the primary obstacles to Evolutionary Algorithms (EAs) fulfilling their promise as easy to use general-purpose problem solvers is the difficulty of correctly configuring them for specific problems such as to obtain satisfactory performance. This paper introduces the concept of democratic, semi-autonomous parent selection by encoding and evolving population rating operators as in Genetic Programming and shows the potential of extending self-adaptation by pairing mates using an adaptation of the Stable Roommates problem. Replacing the typical general parent selection algorithm with autonomously evolved individual selection parameters has the prospective to bring EAs a step closer to their promise as …

Go to article

Greedy Population Sizing For Evolutionary Algorithms, Ekaterina Smorodkina, Daniel R. Tauritz Jan 2007

Greedy Population Sizing For Evolutionary Algorithms, Ekaterina Smorodkina, Daniel R. Tauritz

Computer Science Faculty Research & Creative Works

The number of parameters that need to be man ually tuned to achieve good performance of Evolutionary Algorithms and the dependency of the parameters on each other make this potentially robust and efficient computational method very time consuming and difficult to use. This paper introduces a Greedy Population Sizing method for Evolutionary Algo rithms (GPS-EA), an automated population size tuning method that does not require any population size related parameters to be specified or manually tuned a priori. Theoretical analysis of the number of function evaluations needed by the GPS EA to produce good solutions is provided. We also perform …

Go to article

Neural Network Controller Development And Implementation For Spark Ignition Engines With High Egr Levels, Jonathan B. Vance, Atmika Singh, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier Jan 2007

Neural Network Controller Development And Implementation For Spark Ignition Engines With High Egr Levels, Jonathan B. Vance, Atmika Singh, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier

Electrical and Computer Engineering Faculty Research & Creative Works

Past research has shown substantial reductions in the oxides of nitrogen (NOx) concentrations by using 10% -25% exhaust gas recirculation (EGR) in spark ignition (SI) engines (see Dudek and Sain, 1989). However, under high EGR levels, the engine exhibits strong cyclic dispersion in heat release which may lead to instability and unsatisfactory performance preventing commercial engines to operate with high EGR levels. A neural network (NN)-based output feedback controller is developed to reduce cyclic variation in the heat release under high levels of EGR even when the engine dynamics are unknown by using fuel as the control input. A separate …

Go to article

Two Neural Network Based Decentralized Controller Designs For Large Scale Power Systems, Wenxin Liu, Jagannathan Sarangapani, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Mariesa Crow, David A. Cartes Jan 2007

Two Neural Network Based Decentralized Controller Designs For Large Scale Power Systems, Wenxin Liu, Jagannathan Sarangapani, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Mariesa Crow, David A. Cartes

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents two neural network (NN) based decentralized controller designs for large scale power systems' generators, one is for the excitation control and the other is for the steam valve control. Though the control signals are calculated using local signals only, the transient and overall system stabilities can be guaranteed. NNs are used to approximate the unknown and/or imprecise dynamics of the local power system and the interconnection terms, thus the requirements for exact system parameters are released. Simulation studies with a three machine power system demonstrate the effectiveness of the proposed controller designs.

Go to article

A Comparison Of Print Advertisements From Egypt, Lebanon, Kuwait, Saudi Arabia, United Arab Emirates And The United States, Gilberto De Los Santos, Caroline Fisher, Salma Ghanem, Morris Kalliny, Anshu Saran Jan 2007

A Comparison Of Print Advertisements From Egypt, Lebanon, Kuwait, Saudi Arabia, United Arab Emirates And The United States, Gilberto De Los Santos, Caroline Fisher, Salma Ghanem, Morris Kalliny, Anshu Saran

Business and Information Technology Faculty Research & Creative Works

This study examines cultural differences between the United States and the Arab world regarding low/high context, collectivism/individualism, time orientation and man's relationship with nature in print advertising. Study reveals that the main differences between the United States and the Arab world include cultural values that are embedded in religious values and beliefs.

Go to article

Cultural Values Reflected In Arab And American Television Advertising, Morris Kalliny, Lance Gentry Jan 2007

Cultural Values Reflected In Arab And American Television Advertising, Morris Kalliny, Lance Gentry

Business and Information Technology Faculty Research & Creative Works

This study examines cultural values as reflected in U.S. And the Arab world television advertising. A total of 866 television commercials from Egypt, Kuwait, Lebanon, Saudi Arabia, United Arab Emirates and the United States were analyzed. Contrary to the common notion that the U.S. culture and the Arabic culture are vastly different, we found many similarities between the two cultures regarding TV advertising content and appeal. The findings contribute to the debate of standardization versus adaptation of international advertising.

Go to article

Spatial Diversity In Signal Strength Based Wlan Location Determination Systems, Anil Ramachandran, Jagannathan Sarangapani Jan 2007

Spatial Diversity In Signal Strength Based Wlan Location Determination Systems, Anil Ramachandran, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

Literature indicates that spatial diversity can be utilized to compensate channel uncertainties such as multipath fading. Therefore, in this paper, spatial diversity is exploited for locating stationary and mobile objects in the indoor environment. First, space diversity technique is introduced for small scale motion and temporal variation compensation of received signal strength and it is demonstrated analytically that it enhances location accuracy. Small scale motion refers to movements of the transmitter and/or the receiver of the order of sub-wavelengths while temporal effects refer to environmental variations with time. A novel metric is introduced for selection combining in order to improve …

Go to article

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.

Go to article

First Prev Next Last