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Testing and Maximum Power Extraction of Photovoltic Panels

1:00 p.m. Wednesday, Aug. 17, 2005

in EE 213

by Yingying Kuai

Abstract

Photovoltaic (PV) power systems are playing an increasingly important role in supplying the world's electricity demands. PV panels are the fundamental power generation unit in PV power systems. This seminar first introduces the operation principles and electric characteristics of the PV panels. Secondly, an electronic device for testing the PV panels under field conditions is described. The device uses a linear power metal-oxide-field-effect transistor (MOSFET) as the active element and traces the current-voltage (I-V) and power-voltage (P-V) characteristics of the PV panels almost instantaneously. Thirdly, an improved, voltage-based, maximum power point tracking (MPPT) method is proposed. The method is based on the basic I-V characteristic of the PV panels and is accurate under all weather conditions. The control circuits are simple and cost effective. The performance of the PV power system with MPPT is further analyzed by obtaining the PV panels' frequency response with respect to the load resistance using small-signal modeling technique.

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Fame and Fortune Are Not Mutually Exclusive

12:30 p.m. Tuesday, Aug. 30, 2005

in EE 123

by Kevin Crawford , Licensing Associate

Abstract

Against a backdrop description of NDSU's intellectual property development process, this presentation describes the support means used to help protect the creativity and research of the NDSU faculty, research staff and students, ways to harmonize your discovery reporting obligations with your research and publishing timelines, and ways NDSU intellectual property can put revenue back into your pocket and department.

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RFID Cattle Tags

12:30 p.m. Tuesday, Sept. 6, 2005

in EE 123

by Dr. Jacob Glower

Abstract

The viability of using high-frequency radio frequency identification (RFID) tags to identify cattle in the field was tested. Two sets of 916MHz passive RFID ear tags were developed and placed on 23 cows. These 23 cows were then run through chutes to determine the probability of reading these tags under field conditions. Two conditions were tested: cows running through the chute in single file and running en-mass through a 3m gate. It was found that, with the use of high-frequency RFID tags, cattle could be successfully identified as they ran through a gate with a probability of detection of at least 99.95% with an 80% confidence level.

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Sorting of Analog Voltages

12:30 p.m. Tuesday, Sept. 13, 2005

in EE 123

by Dr. Bapeswara Rao

Abstract

A procedure to sort a set of d.c. voltages will be presented. The voltages may be generated by a set of thermocouples inserted at various locations to monitor the temperature of a body/machine. The circuit, based on the procedure described, also indicates the location number at which a given voltage exists (1). If time permits, a digital circuit to determine the maximum value of the inputs will also be presented (2)

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Complex Problem-Solving:
The Ongoing Biomedical Story with Diabetes Mellitus

12:30 p.m. Tuesday, Sept. 20, 2005

in EE 123

by Dr. Gary K. Clambey

Abstract

While scientists and engineers address a wide range of interesting and difficult problems, some especially stand out because, while long recognized, the causes, solutions, and prevention of these problems have not been readily resolved. Diabetes mellitus (DM), first recognized centuries ago and now an increasing, though treatable, set of conditions certainly is such a biomedical problem. After briefly introducing normal human metabolic function, DM, in its various forms, will be described. Physiological malfunctions and consequences, together with therapeutic approaches, will be considered, with particular attention to insulin-dependent DM. Health care providers, biomedical scientists, engineers and other technologists, and social scientists have all contributed to addressing this health issue, even though, in most instances, prevention or a cure still elude us.

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Two-for-the-price-of-one week!

12:30 p.m. Tuesday, Sept. 27, 2005

in EE 123

DSP-based EIS Instrument Utilizing Low Peak-Factor Pseudo-Logarithmically Spaced Multi-Frequency Test Signals

by Dr. Roger Green

Abstract

This presentation overviews recent advancements by NDSU ECE researchers in the design of electrochemical impedance spectroscopy (EIS) instruments, with particular emphasis on the use of EIS systems as corrosion monitors for Air Force applications.

Understanding and Enhancing the Performance of Parallel Clockless Transient Waveform Digitizers

by Kurt Peterson

Abstract

This presentation discusses the characterization and correction of errors for a prototype parallel clockless digitizer currently under development at Dakota Technologies Inc. as well as the digitizer's application to laser induced fluorescence (LIF) systems.

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Describing Dynamic Systems With Delay Differential Equations

12:30 p.m. Tuesday, Oct. 4, 2005

in EE 123

by Dr. Rajesh Kavasseri

Abstract

The dynamics of several physical, engineering and biological systems are often modeled by ordinary differential equations (ODEs). However, the inherent presence of time delays in some systems necessitates a description of the dynamics in terms of delay differential equations (DDEs). While delays can potentially alter the qualitative nature of system dynamics, DDE models are usually harder to analyze compared to ODEs.

This talk will present two examples from two diverse settings namely power systems and genetic regulatory networks where time delays are considered in formulating the system dynamics. In the former case, the effect of time delays (due to wide area measurement controllers) on the excitation control loop of a synchronous generator is examined. Specifically, it is shown that the system undergoes a delay induced Hopf bifurcation leading to the onset of sustained periodic oscillations. In the latter case, the effect of time delays on the dynamics of a bistable genetic toggle switch is studied. It is shown that while degradation delays destabilize the toggle, the switch is robust to transcriptional delays that affect repression.

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The Power of e

12:30 p.m. Tuesday, Oct. 11, 2005

in EE 123

by Dr. David Farden

Abstract

The function f(x) = e^x and its properties are the foundation of much of electrical engineering. From the basic properties of e, constant coefficient linear differential equations can be solved using algebra. This enables a complex version of Ohm's Law which applies to any lumped parameter linear time-invariant electrical circuit. The application of eigensignals and superposition allows very easy interpretations of Fourier series, Fourier Transforms, and Laplace Transforms. Some fundamental results are reviewed, along with geometrical insights and extensions to time-varying linear systems.

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Implementation and Performance Analysis of IEEE 802.11i Standard Using the IXP425 Network Processor

12:30 p.m. Tuesday, Oct. 18, 2005

in EE 123

by Hareesh Khattri

Abstract

In recent years the IEEE 802.11b standard has been widely used for wireless local area network (WLAN) deployments. The need for higher data rates has led to the generation of 802.11a and 802.11g standards. The original 802.11 standard addressed security concerns by defining the wired equivalent privacy (WEP). The WEP security design has since then been shown to have many deficiencies. The new IEEE 802.11i standard approved in June 2004 is a result of an effort to fix the security issues with WEP. In this seminar we present an implementation and performance analysis of the new IEEE 802.11i standard. An access point is first implemented using the Intel IXP425 processor and IEEE 802.11b Intersil Prism 2 wireless cards cards. Clients are laptops with wireless communication capability. The performance analysis of the setup was done using Ixchariot network performance testing software. Tests were carried out to test the performance of the network for TCP, UDP, and VOIP protocol traffic.

This work was supported in part by the Intel Corporation.

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Random Sample Generation from Arbitrary Distributions

Controllable and Repeatable Independent Samples for Simulation

12:30 p.m. Tuesday, Oct. 25, 2005

in EE 123

by Floyd Patterson

Abstract

Mimicking uncertainty to better understand random phenomena is aided by applying controlled simulation experiments with pseudo-random inputs or parameters. Methods for generating independent samples from arbitrary mono-variate and bi-variate distributions will be presented with emphasis on continuous single random variables, with possible discontinuities in the cumulative distribution function.

The seminar will begin with a review of some basic probability concepts, then illustrate how to ascertain distribution models from histograms versus cumulative distribution functions, and finally obtain and verify the validity of the desired pseudo-random sample distribution. MATLAB will be used to provide dynamic illustrations of procedures.

Hopefully, time will allow attendees to predict the future of a multi-variate and jointly normal stochastic function in competition with a computer algorithm.

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QoS Assurance in Internet Services

12:30 p.m. Tuesday, Nov. 1, 2005

in EE 123

by Dr. Cheng-Zhong Xu^*

Department of Electrical and Computer Engineering
Wayne State University
Detroit, MI 48202

Abstract

Today's Internet Services like email and e-commerce are largely provided in a best-effort and same-service-to-all manner. In practice, it is often more compelling to offer different levels of quality of service (QoS) to different clients according to their profiles and server load conditions. For example, in an on-line trading site or a Web e-mail server, a service differentiation model would provide preferred customers with QoS assurance and basic customers degraded services when the server becomes overloaded. A service differentiation architecture would offer a strong incentive for a differentiated pricing model for the next generation of Internet services. Even on an indiscriminate Web site, the architecture can isolate the performance of different traffic. By downgrading the quality of certain classes of traffic, it controls the behaviors of aggressive clients and ensures fair sharing between different classes of clients. Fairness assurance automatically builds a firewall around aggressive clients and protects the server from distributed denial-of-service attack.

In this talk, I will present our recent research towards the QoS assurance on Internet servers. Focus will be on a QoS-aware server resource management framework, eQoS, for the provisioning of client-perceived end-to-end relative and absolute response time guarantees. At the heart of the framework is a feedback controller that regulates the process of resource allocation between different classes of requests in response to measured performance errors. Experimental results on an Apache/Linux server demonstrated the stability and adaptivity of the approach, even in the presence of high dynamism of Internet traffic. The system was tested on PlanetLab, a world wide distributed Internet testbed.

^* Dr. Cheng-Zhong Xu is an Associate Professor in the Department of Electrical and Computer Engineering of Wayne State University. Dr. Xu's research interests include resource management in distributed and parallel systems, high performance cluster computing, mobile code, and scalable and secure Internet services. He has published around one hundred peer-reviewed journal and conference papers in these areas. He is the leading co-author of the book Load Balancing in Parallel Computers (Kluwer Academic, 1997). It was the first research monograph that addressed the load balancing issue systematically. Dr. Xu’s most recent book Scalable and Secure Internet Services and Architecture (Chapman & Hall/CRC Press, 2005) provides an in-depth analysis of key performance and security issues in a unified framework and paves a way to the next generation of Internet services. Dr. Xu's research was supported in part by U.S. NSF and NASA. He is a recipient of the "Faculty Research Award" of Wayne State University in 2000, the "President's Award for Excellence in Teaching" in 2002, and the "Career Development Chair Award" in 2003. Dr. Xu received a Ph.D.in computer science from the University of Hong Kong in 1993.

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Two Versions of Computer Supported Group Work

and

Video Conferencing and Why It Is Not Now Multicasting

12:30 p.m. Tuesday, Nov. 8, 2005

in EE 123

by Dr. Paul Juell

Department of Computer Science and Operations Research

Abstracts

Two Versions of Computer Supported Group Work

Examples of group work tools:

• calendering
• source mantainence system
• workflow [often drawn as Petri nets]
• IM (internet messaging) and email

Wiki and the system I use: TWiki

• a WIKI is a collection of world writable web pages
• allows groups to do things some tools make hard or impossible
• relies on a culture - this is open to world (works because of social pressure and rollback)
• allows group dynamics to evolve (but often needs a starting example or need)
• although the Wiki philosphy is public control - it works well with small and private groups - the limited group view is often either used on an intranet or with security turned on
• can serve structured problems - for examle the TWiki system has a built in document depository
• some completing technoligies (document depositories, workflow systems)
• systems internally either data base or file system (TWiki a file system)

Video Conferencing and Why It Is Not Now Multicasting

Video conferencing (and multicast): I have been running a world wide multicast since about 1995 called "Window on NDSU". Multicasting vs. point casting: some issues, hardware, firmware, updates, non-working sites. Currently the standard for codex is 264. This supports high quality images, over phone lines (also known as POTS).

• multicasting and multicast groups (224.0.0.0 to 239.255.255.255)
• the simple ethernet (the campus LAN, hubs and off campus)
• MBONE on the simple network (tunnels, software repeaters and known lists)
• central switched networks
• the rise of the problem (smart switches now need to know about multicast)
• why does NDSU work?
• MBONE part(?) of the network and switch
• repeaters and islands of multicast
• smart switches for buildings and the spread of the problem
• switches everywhere
• the new hardware solution - the MCU (the Multipoint Control Unit)

The co-story - pointcasting:

• some systems for point to point
• some multicast (where it worked)
• small volume - pointcast easy (get Real)
• scale up - just buy a faster machine
• scale up - just buy a bigger pipe
• scale up - on demand

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RFID and EMC: A Brief Introduction

12:30 p.m. Tuesday, Nov. 15, 2005

in EE 123

by Dr. Robert Nelson

Abstract

This talk will provide a brief introduction to the topic of RFID (Radio Frequency Identification), with particular emphasis on how one might view the RFID system from an electromagnetics/antennas perspective. A brief look will also be provided of the potential of interference between RFID systems and other electronic systems.

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Inter-regional Market Coordination Using Decentralized Market Optimization Algorithm

12:30 p.m. Tuesday, Nov. 22, 2005

in EE 123

by Anni Huang

Abstract

Energy trading between regions is intended to improve the overall economic efficiency of electricity markets and the reliability of interconnected power systems. The operation of interconnected electricity markets requires effective inter-regional market coordination to maximize the overall social welfare of markets. In this talk, I will present an inter-regional market coordination method using decentralized market optimization algorithm to coordinate energy trading between regions. A numerical example will be presented to show the effectiveness of the proposed method.

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Conversion and Control of Photo-Voltaic Power

12:30 p.m. Tuesday, Nov. 29, 2005

in EE 123

by Marilyn Jayachandran

Abstract

Photo-voltaic (PV) energy has been explored as a promising renewable energy source during the last several years. In this presentation, two simple and economical power conditioners to convert the power available from PV panels into useable forms of electrical energy are presented.

First, a PSPICE simulation model for the PV panel is developed based on the experimental results obtained on a set of 120W PV panels. This model is used to study the operation of the PV panel when its power is converted and fed to the grid.

Next, a conversion scheme for operating a thyristor bridge as a line-commutated inverter for transferring power from the PV panel to the grid at any insolation (light) level is presented. In this, a voltage-based maximum power point tracking (MPPT) method to harvest the maximum power output from the converter is used.

Last, a buck-boost DC-DC power converter for charging a set of batteries from the PV panel at the maximum power point (MPP) is developed.

Simulation and experimental results will be presented.

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