Engineering Commons^™

System For Sequentially Providing Aberation Corrected Electromagnetic Radation To A Spot On A Sample At Multiple Angles Of Incidence, Martin M. Liphardt, John A. Woollam,

Department of Electrical and Computer Engineering: Faculty Publications

A system for sequentially providing electromagnetic radia tion to a spot on a sample at different angles of incidence, and after reflection therefrom into a detector. The system includes a plurality of spherical mirrors, and a refractive element for correcting aberration.

Rotating Or Rotatable Compensator Systemi Providing Aberation Corrected Electromagnetic Raadation To A Spot On A Sample At Multiple Angles Of Ancidence, Martin M. Liphardt, Blaine D. Johs, Jeffrey S. Hale, Craig M. Herzinger, Steven E. Green, Ping He, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

The present invention relates to ellipsometer systems, and more particularly to ellipsometer systems comprising trans missive rotating or stepwise rotatable compensators for continuously or step-wise varying polarization states and further comprising transmissive multi-element lens focusing of a spectroscopic electromagnetic beam into a small, chromatically relatively undispersed area spot on a sample system. The ellipsometer system optionally is present in an environmental control chamber.

Computational Complexity Of Determining Which Statements About Causality Hold In Different Space-Time Models, Vladik Kreinovich, Olga Kosheleva

Departmental Technical Reports (CS)

Causality is one of the most fundamental notions of physics. It is therefore important to be able to decide which statements about causality are correct in different models of space-time. In this paper, we analyze the computational complexity of the corresponding deciding problems. In particular, we show that: for Minkowski space-time, the deciding problem is as difficult as the Tarski's decision problem for elementary geometry, while for a natural model of primordial space-time, the corresponding decision problem is of the lowest possible complexity among all possible spacetime models.

Interval Computations And Interval-Related Statistical Techniques: Tools For Estimating Uncertainty Of The Results Of Data Processing And Indirect Measurements, Vladik Kreinovich

Departmental Technical Reports (CS)

In many practical situations, we only know the upper bound D on the (absolute value of the) measurement error d, i.e., we only know that the measurement error is located on the interval [-D,D]. The traditional engineering approach to such situations is to assume that d is uniformly distributed on [-D,D], and to use the corresponding statistical techniques. In some situations, however, this approach underestimates the error of indirect measurements. It is therefore desirable to directly process this interval uncertainty. Such "interval computations" methods have been developed since the 1950s. In this chapter, we provide a brief overview of related …

Reasons Why Mobile Telephone Conversations May Be Annoying: Considerations And Pilot Studies, Nigel Ward, Anais G. Rivera, Alejandro Vega

Departmental Technical Reports (CS)

Mobile telephone conversations in public places are often annoying to bystanders. Previous work has focused on the psychological and social causes for this, but has not examined the possible role of properties of the communication channel. In our paper "Do Bystanders and Dialog Participants Differ in Preferences for Telecommunications Channels?" (21st International Symposium on Human Factors in Telecommunication, 2008) we consider the possibility that a reason for the annoyance could be that bystander preferences differ from talker preferences, but conclude that this is in fact unlikely to be a major factor. This technical report provides supplemental information, specifically a broader …

Evaluation Of Robocode As A Teaching Tool For Computer Programming, Arnold Hensman

Conference Papers

Robocode began as an educational tool to aid in learning Java programming. It has since evolved into something of a phenomenon, as the prospect of creating simple to complex virtual tanks appears to pose an attractive challenge to both novice and expert programmers alike. What started out as a teaching tool has grown into a worldwide network of competitors, all keen to prove that their ‘bot’ stands out from the crowd. Competitions are well organised and many Robocode events are a PR dream for the computing companies that sponsor them. Without a doubt, this easy to use application has sparked …

Optimal Receiver For Space Time Spreading Across A Time Hopping Ppm Over Ultra Wideband Saleh-Valenzuela Mimo Channel, Peter Vial, Beata J. Wysocki, Tadeusz A. Wysocki

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

This paper outlines a technique which can use multiple transmit antennas to send more than one binary bit using the same number of transmit antennas over a single transmission. It uses Ultra Wideband orthogonal pulse position modulation to achieve this, with the receiver employing a Rake receiver and a Maximum Ratio Combiner optimal detector. This is done over a Space Time Spreading Time Hopping Ultra Wideband Pulse Position Modulation system assuming a rich multipath Saleh-Valenzuela MIMO channel model. Simulation results indicate that a significant gain can be achieved compared with other proposed schemes utilising multiple transmit antennas for Ultra Wide …

Scalability Of Manet Routing Protocols For Heterogeneous And Homogenous Networks, Huda Al Amri, Mehran Abolhasan, Tadeusz Wysocki

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

In Mobile Ad hoc Network (MANET), mobility, traffic and node density are main network conditions that significantly affect the performance of routing protocols. Much of the previous researches in MANET routing have focused on developing strategies, which suit one specific networking scenario. Therefore, there is no existing protocol that can work well in all different networking scenarios. This paper reviews characteristics of each different classes of routing protocols. Moreover, most of current routing protocols assume homogeneous networking conditions where all nodes have the same capabilities and resources. Although homogenous networks are easy to model and analysis, they exhibits poor scalability …

Closed-Form Derivations Of Isi And Mui For Time-Reversed Ultra Wideband, K. Popovski, Beata J. Wysocki, Tadeusz Wysocki

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Through transmitter pre-filtering, a time reversed UWB system is capable if harnessing a multipath channel to achieve temporal and spatial focusing. Unfortunately, large RMS channel delay spread leads to significant intersymbol and multiuser interference. This paper presents closed-form expressions for self and multi-user interference for a UWB system utilizing a time-reversed approach. The influence of user multiplexing codes is taken to account through incorporation of a ‘separation probability’, which characterizes a family of hopping sequences. The standardized IEEE 802.15.3a channel model is applied, and the derived performances are compared with that of a simulated time hopped time-reversed UWB system.

Self-Organizing Neural Architectures And Cooperative Learning In A Multiagent Environment, Dan Xiao, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

Temporal-Difference–Fusion Architecture for Learning, Cognition, and Navigation (TD-FALCON) is a generalization of adaptive resonance theory (a class of self-organizing neural networks) that incorporates TD methods for real-time reinforcement learning. In this paper, we investigate how a team of TD-FALCON networks may cooperate to learn and function in a dynamic multiagent environment based on minefield navigation and a predator/prey pursuit tasks. Experiments on the navigation task demonstrate that TD-FALCON agent teams are able to adapt and function well in a multiagent environment without an explicit mechanism of collaboration. In comparison, traditional Q-learning agents using gradient-descent-based feedforward neural networks, trained with the …

What Is Rcu, Fundamentally?, Paul E. Mckenney, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Read-copy update (RCU) is a synchronization mechanism that was added to the Linux kernel in October of 2002. RCU achieves scalability improvements by allowing reads to occur concurrently with updates. In contrast with conventional locking primitives that ensure mutual exclusion among concurrent threads regardless of whether they be readers or updaters, or with reader-writer locks that allow concurrent reads but not in the presence of updates, RCU supports concurrency between a single updater and multiple readers. RCU ensures that reads are coherent by maintaining multiple versions of objects and ensuring that they are not freed up until all pre-existing read-side …

Application Of Intermediate Wavelength Band Spectroscopic Ellipsometry To In-Stu. Real Time Fabrication Of Multiple Layer Alternating Hghalow Refractive Index Filters, Blaine D. Johs, Jeffery S. Hale, John A. Woollam, Craig M. Herzinger

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed is application of oblique angle of incidence, reflection and/or transmission mode spectroscopic ellipsometry PSI and/or DELTA, (including combinations thereof and/or mathematical equivalents), vs. wavelength data over an intermediate wavelength band range around a pass or reject band, to monitor and/or control fabrication of multiple layer high/low refractive index band-pass, band-reject and varied attenuation vs. wavelength thin film interference filters, either alone or in combination with transmissive non-ellipsometric electromagnetic beam turning point vs. layer data obtained at an essentially normal angle of incidence.

A Theoretical Framework For Quality-Aware Cross-Layer Optimized Wireless Multimedia Communications, Song Chi, Haohong Wang, Dalei Wu

Department of Electrical and Computer Engineering: Faculty Publications

Although cross-layer has been thought as one of themost effective and efficient ways formultimedia communications over wireless networks and a plethora of research has been done in this area, there is still lacking of a rigorous mathematical model to gain indepth understanding of cross-layer design tradeoffs, spanning from application layer to physical layer. As a result, many existing cross-layer designs enhance the performance of certain layers at the price of either introducing side effects to the overall system performance or violating the syntax and semantics of the layered network architecture. Therefore, lacking of a rigorous theoretical study makes existing cross-layer …

Computing Population Variance And Entropy Under Interval Uncertainty: Linear-Time Algorithms, Gang Xiang, Martine Ceberio, Vladik Kreinovich

Departmental Technical Reports (CS)

In statistical analysis of measurement results, it is often necessary to compute the range [V-,V+] of the population variance V=((x1-E)^2+...+(xn-E)^2)/n (where E=(x1+...+xn)/n) when we only know the intervals [Xi-Di,Xi+Di] of possible values of the xi. While V- can be computed efficiently, the problem of computing V+ is, in general, NP-hard. In our previous paper "Population Variance under Interval Uncertainty: A New Algorithm" (Reliable Computing, 2006, Vol. 12, No. 4, pp. 273-280), we showed that in a practically important case, we can use constraints techniques to compute V+ in time O(n*log(n)). In this paper, we provide new algorithms that compute V- …

A Fitness Function To Find Feasible Sequences Of Method Calls For Evolutionary Testing Of Object-Oriented Programs, Myoung Yee Kim, Yoonsik Cheon

Departmental Technical Reports (CS)

In evolutionary testing of an object-oriented program, the search objective is to find a sequence of method calls that can successfully produce a test object of an interesting state. This is challenging because not all call sequences are feasible; each call of a sequence has to meet the assumption of the called method. The effectiveness of an evolutionary testing thus depends in part on the quality of the so-called fitness function that determines the degree of the fitness of a candidate solution. In this paper, we propose a new fitness function based on assertions such as method preconditions to find …

Propagation And Provenance Of Probabilistic And Interval Uncertainty In Cyberinfrastructure-Related Data Processing And Data Fusion, Paulo Pinheiro Da Silva, Aaron A. Velasco, Martine Ceberio, Christian Servin, Matthew G. Averill, Nicholas Ricky Del Rio, Luc Longpre, Vladik Kreinovich

Departmental Technical Reports (CS)

In the past, communications were much slower than computations. As a result, researchers and practitioners collected different data into huge databases located at a single location such as NASA and US Geological Survey. At present, communications are so much faster that it is possible to keep different databases at different locations, and automatically select, transform, and collect relevant data when necessary. The corresponding cyberinfrastructure is actively used in many applications. It drastically enhances scientists' ability to discover, reuse and combine a large number of resources, e.g., data and services.

Because of this importance, it is desirable to be able to …

Statistical Hypothesis Testing Under Interval Uncertainty: An Overview, Vladik Kreinovich, Hung T. Nguyen, Sa-Aat Niwitpong

Departmental Technical Reports (CS)

An important part of statistical data analysis is hypothesis testing. For example, we know the probability distribution of the characteristics corresponding to a certain disease, we have the values of the characteristics describing a patient, and we must make a conclusion whether this patient has this disease. Traditional hypothesis testing techniques are based on the assumption that we know the exact values of the characteristic(s) x describing a patient. In practice, the value X comes from measurements and is, thus, only known with uncertainty: X =/= x. In many practical situations, we only know the upper bound D on the …

How To Estimate, Take Into Account, And Improve Travel Time Reliability In Transportation Networks, Ruey L. Cheu, Vladik Kreinovich, Francois Modave, Gang Xiang, Tao Li, Tanja Magoc

Departmental Technical Reports (CS)

Many urban areas suffer from traffic congestion. Intuitively, it may seem that a road expansion (e.g., the opening of a new road) should always improve the traffic conditions. However, in reality, a new road can actually worsen traffic congestion. It is therefore extremely important that before we start a road expansion project, we first predict the effect of this project on traffic congestion.

Traditional approach to this prediction is based on the assumption that for any time of the day, we know the exact amount of traffic that needs to go from each origin city zone A to every …

Are There Rearrangement Hotspots In The Human Genome?, Max A. Alekseyev, Pavel A. Pevzner

Faculty Publications

In a landmark paper, Nadeau and Taylor [18] formulated the random breakage model (RBM) of chromosome evolution that postulates that there are no rearrangement hotspots in the human genome. In the next two decades, numerous studies with progressively increasing levels of resolution made RBM the de facto theory of chromosome evolution. Despite the fact that RBM had prophetic prediction power, it was recently refuted by Pevzner and Tesler [4], who introduced the fragile breakage model (FBM), postulating that the human genome is a mosaic of solid regions (with low propensity for rearrangements) and fragile regions (rearrangement hotspots). However, the rebuttal …

Detecting And Segmenting Un-Occluded Items By Actively Casting Shadows, Tze K Koh, Amit Agrawal, Ramesh Raskar, Steve Morgan, Nicholas Miles, Barrie Hayes-Gill

Research Collection College of Integrative Studies

We present a simple and practical approach for segmenting un-occluded items in a scene by actively casting shadows. By ‘items’, we refer to objects (or part of objects) enclosed by depth edges. Our approach utilizes the fact that under varying illumination, un-occluded items will cast shadows on occluded items or background, but will not be shadowed themselves.We employ an active illumination approach by taking multiple images under different illumination directions, with illumination source close to the camera. Our approach ignores the texture edges in the scene and uses only the shadow and silhouette information to determine the occlusions. We show …

Optical Reading And Playing Of Sound Signals From Vinyl Records, Arnold Hensman, Kevin Casey

Conference Papers

While advanced digital music systems such as compact disk players and MP3 have become the standard in sound reproduction technology, critics claim that conversion to digital often results in a loss of sound quality and richness. For this reason, vinyl records remain the medium of choice for many audiophiles involved in specialist areas. The waveform cut into a vinyl record is an exact replica of the analogue version from the original source. However, while some perceive this media as reproducing a more authentic quality then its digital counterpart, there is an absence a safe playback system. Contact with the stylus …

Usability Inspection Methods After 15 Years Of Research And Practice, David G. Novick, Tasha Hollingsed

Departmental Papers (CS)

Usability inspection methods, such as heuristic evaluation, the cognitive walkthrough, formal usability inspections, and the pluralistic usability walkthrough, were introduced fifteen years ago. Since then, these methods, analyses of their comparative effectiveness, and their use have evolved in different ways. In this paper, we track the fortunes of the methods and analyses, looking at which led to use and to further research, and which led to relative methodological dead ends. Heuristic evaluation and the cognitive walkthrough appear to be the most actively used and researched techniques. The pluralistic walkthrough remains a recognized technique, although not the subject of significant further …

Toward A More Accurate View Of When And How People Seek Help With Computer Applications, David G. Novick, Edith Elizalde, Nathaniel Bean

Departmental Papers (CS)

Based on 40 interviews and 11 on-site workplace observations of people using computer applications at work, we confirm that use of printed and on-line help is very low and find that providing greater detail of categories solution methods can present a more realistic picture of users’ behaviors. Observed study participants encountered a usability problem on average about once every 75 minutes and typically spent about a minute looking for a solution. Participants consumed much more time when they were unaware of a direct way of doing something and instead used less effective methods. Comparison of results from different data-collection methods …

Use Of Ellipsometry And Surface Plasmon Resonance In Monitoring Thin Film Deposition Or Removal From A Substrate Surface, John A. Woollam, Blaine D. Johs, Thomas E. Tiwald, Martin M. Liphardt, James D. Welch

Department of Electrical and Computer Engineering: Faculty Publications

Improved methodology for monitoring deposition or removal of material to or from a process and/or Wittness substrate Which demonstrates a negative e1 at some Wave length. The method involves detection of changes in P-polarized electromagnetism ellipsometric DELTA at SPR Resonance Angle-of-lncidence (A01) to monitor deposition of and/or removal of minute amounts of materials onto, or from, said process and/or Witness substrate. The methodology can optionally monitor ellipsometric PS1, and involves simultaneously or sequentially applying non-P-polarized electromagnetism at the same angle of incidence, or electromagnetic radiation of any polarization at a different angle-of-incidence and Wavelength to the process or Witt ness …

A Two-Phase Approach To Interactivity Enhancement For Large-Scale Distributed Virtual Environments, Nguyen Binh Duong Ta, Suiping Zhou

Research Collection School Of Computing and Information Systems

Distributed virtual environments (DVEs) are distributed systems that allow multiple geographically distributed clients (users) to interact simultaneously in a computer-generated, shared virtual world. Applications of DVEs can be seen in many areas nowadays, such as online games, military simulations, collaborative designs, etc. To support large-scale DVEs with real-time interactions among thousands or even more distributed clients, a geographically distributed server architecture (GDSA) is generally needed, and the virtual world can be partitioned into many distinct zones to distribute the load among the servers. Due to the geographic distributions of clients and servers in such architectures, it is essential to efficiently …

Flying Mobile On-Board Ellipsometer, Polarimeter, Reflectometer And The Like Systems, Blaine D. Johs,, Ping He, Martin M. Liphardt, Christopher A. Goeden, John A. Woollam, James D. Welch

Department of Electrical and Computer Engineering: Faculty Publications

A substantially self-contained “on-boar ” material system investigation system functionally mounted on a three dimen sional locational system to enable positioning at desired locations on, and distances from, the surface of a large sample, including the capability to easily and conveniently change the angle-of-incidence of a beam of electromagnetic radiation onto a sample surface.

Learning Navigation For Recharging A Self-Sufficient Colony Robot, Gary Parker, Richard Zbeda

Computer Science Faculty Publications

It is advantageous for colony robots to be autonomous and self-sufficient. This requires them to perform their duties while maintaining enough energy to operate. Previously, we reported the equipping of power storage for legged robots with high capacitance capacitors, the configuration of one of these robots to effectively use its power storage in a colony recharging system, and the learning of a control program that enabled the robot to navigate to a charging station in simulation. In this work, we report the learning of a control program that allowed the simulated robot to perform area coverage in a self-sufficient framework …

Ceg 320/520: Computer Organization, Michael L. Raymer

Computer Science & Engineering Syllabi

No abstract provided.

Ceg 221: Advanced C Programming For Engineers, Robert Helt

Computer Science & Engineering Syllabi

This course introduces advanced constructs, algorithms, and data structures in the C programming language. Emphasis is on problem solving and techniques useful to engineers. Topics include functions, array, pointers, structures as well as sorting algorithms, linked lists, complex numbers, stacks, queues, hash tables, and binary trees. 4 credit hours. Prerequisite: CEG220 (Introduction to C Programming for Engineers).

Ceg 420/620: Computer Architecture, Jack Jean

Computer Science & Engineering Syllabi

No abstract provided.