Digital Commons Network^™

Quantum Gravitational Corrections To Black Hole Geometries, Marco Cavaglia, A. Fabbri

Physics Faculty Research & Creative Works

We calculate perturbative quantum gravity corrections to eternal two-dimensional black holes. We estimate the leading corrections to the AdS₂ black hole entropy and determine the quantum modification of N-dimensional Schwarzschild spacetime.

Experimental Implementation Of Adaptive-Critic Based Infinite Time Optimal Neurocontrol For A Heat Diffusion System, Prashant Prabhat, S. N. Balakrishnan, Dwight C. Look

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Recently the synthesis methodology for the infinite time optimal neuro-controllers for PDE systems in the framework of adaptive-critic design has been developed. In this paper, first we model an experimental setup representing one dimensional heat diffusion problems. Then we synthesize and implement an adaptive-critic based neuro-controller for online temperature profile control of the experimental setup.

Health Promotion Evaluation And Needs Assessment In The Transylvania Region Of Romania, Bryan C. Byrd

Dissertations and Theses @ UNI

Since the revolution of 1989, Romania has been undergoing wide ranging changes affecting all aspects of the country including health promotion. As common to many newly independent states (NIS) the changes in socio-economics, on-going poverty, unemployment status, and the overall culture shock of political transition, has resulted in health characteristics and indicators improving in some areas but suffering in others. This project was initiated as a descriptive study of the health promotion practices of Transylvania, Romania. The goal of the research was to describe and discover the philosophical practices driving current Romanian health promotion practices, as well as to conduct …

Health Concerns Of Reentry Nontraditional Women Students: A Survey Of A Community College In Eastern Iowa, Diana D. Cooke Gehrke

Dissertations and Theses @ UNI

The purpose of this study was to investigate the health concerns ofreentry nontraditional women students in a community college in the state oflowa. This group was surveyed in May of2000 at the end of the spring semester. Three hundred nontraditional women students were randomly selected from a population of2,164 names supplied to the researcher by the office of admissions. The women were sent a 103- questionnaire survey accompanied by a cover letter and an informed consent. The categories covered were: (a) demographics, (b) tobacco use, (c) alcohol use, (d) personal relationship issues, (e) causes and management of stress, (f) health …

Piagetian Developmental Reasoning Levels Of High School Students In Differentiated First Year Chemistry Courses, Pamela Kay Brewer-Michael

Dissertations and Theses @ UNI

This research studied the developmental reasoning levels of students in three different first year high school chemistry courses as related to achievement defined by cumulative grade point average and course selection. The Lawson Test of Formal Operations modified by Roy Unruh and Bruce Perry at the University of Northern Iowa was used to determine cognitive developmental level of subjects. A consumer type chemistry course, a traditional high school chemistry course, and an honors course under consideration with Marshalltown Community College for credit status were the three courses utilized in this study. Data was collected in a classroom group setting over …

Identifying And Comparing Misconceptions Held By American And Russian University Students In Mechanics, Alexandra Sokolova

Dissertations and Theses @ UNI

This paper reports on a study of misconceptions held by undergraduate students completing an introductory physics course at the University of Northern Iowa and first-year undergraduate students taking a mechanics course at the Herzen State Pedagogical University of Russia. Existence of misconceptions in mechanics among Russian and American students was investigated prior to instruction and at the completion of the one-semester course. Different teaching approaches were used to introduce the students to mechanics. An activity-based approach was emphasized at UNI and a traditional lecture-lab approach was used at Herzen University. The emphasis of the study was placed on identifying misconceptions …

The Syntheses And Characterizations Of Samarium Arsenic Sulfide Compounds, Chad Michael Delp

Dissertations and Theses @ UNI

The experiments conducted explored lanthanide-arsenic-sulfide ternary systems with particular emphasis on the lanthanide, samarium. A number of stoichiometric mixtures in the samarium arsenic sulfide ternary system were prepared. The samples were sealed into evacuated silica ampoules and then annealed at 900°C. The final products were identified by characterize by X-ray powder diffraction. The powder analyses were used to construct a portion of the ternary phase diagram at 900°C. Every sample contained three common phases, SmAs, AsS and As4S3. Since these compounds were found in every sample, they were not included in the phase diagram. The phase diagram did split into …

Atomic And Molecular Electron Affinities: Photoelectron Experiments And Theoretical Computations, Jonathan C. Rienstra-Kiracofe, Gregory S. Tschumper, Henry F. Schaefer, Sreela Nandi, G. Barney Ellison

Chemistry Faculty Research & Creative Works

A review is given of the experimental determination of electron affinities (EAs). Also considered is the ability of computational chemistry methods to predict electron affinities. The development and present status of computational chemistry techniques for the prediction of atomic molecular EAs is also reviewed in a historical context. Through comparisons to experimental EAs and results from other theoretical methods, analysis of DFT EAs is given. In the context of other theoretical methods, the successes and failures of DFT EA predictions are detailed.

A New Optimal Nonlinear Control Method And Its Application To Missile Guidance Law Design, Ming Xin, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, a new nonlinear control synthesis technique (q-D approximation) is discussed. By adding perturbations to the cost function this approach achieves a suboptimal solution to the Hamilton-Jacobi- Bellman (HJB) equation. By manipulating the perturbation terms both asymptotic stability and optimality properties are obtained. An application to the design of missile guidance law is presented and is compared with a similar technique (State Dependent Riccati Equation technique) used in problems of this class. © 2002 by the author(s).

End To End Congestion Control In High-Speed Networks, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes an adaptive methodology to prevent congestion in packet switched networks such as the Internet, where the internal network nodes convey very little information to the ingress nodes. Two architectures of preventing the congestion are presented: the first one when the traffic arrival rates, and bottleneck queue levels are known and the other when these are unknown. In the latter, the network traffic is estimated online using an adaptive system by measuring the buffer occupancy. In both architectures, the congestion is controlled by adjusting the transmission rates of non real-time and certain real-time sources in response to the …

Distributed Power Control In Wireless Communication Systems, Sarangapani Jagannathan, A. T. Chronopoulos, S. Ponipireddy

Electrical and Computer Engineering Faculty Research & Creative Works

Energy efficiency is a measure of performance in wireless networks. Therefore, controlling the transmitter power at a given node increases not only battery operating life, but also overall system capacity by successfully admitting new links. It is essential to find effective means of power control in point-to-point, broadcasting and multicasting scenarios. Wireless networking presents formidable challenges, and we consider the problem of unicast or point-to-point (peer-to-peer) communication in wireless networks in the presence of other nodes. We study the feasibility of admitting new links in an wireless network operating area while maintaining quality of service (QoS), in terms of signal-to-interference …

A Hybrid System Theoretic Approach For Admission Controller Design In Multimedia Networks, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

A novel real-time discrete-event admission control (AC) scheme for high-speed networks is proposed with the aim of attaining a desired quality of service (QoS) and high network utilization. The AC uses the available capacity from a novel adaptive bandwidth estimation scheme, a congestion indicator derived from a congestion controller, peak bit/cell rate (PBR/PCR) estimate from new sources, along with the desired QoS metrics, and makes decisions whether to 'admit' or 'reject' new sources. The novel aspect of the proposed approach is the application of hybrid system theory to prove the performance of the admission controller, stability and the development of …

Study Of Relative Effectiveness Of Features In Content-Based Image Retrieval, S. R. Subramanya, Jui Che Teng, Yongjian Fu

Electrical and Computer Engineering Faculty Research & Creative Works

Content-based retrieval in image databases requires appropriate features of images to be derived and used in the indexing and searching process. Fast and accurate retrieval is crucial from a user point of view. The kinds of features used, their organization in suitable data structures, and the similarity search scheme, directly affect the speed and quality of content-based retrieval. In this paper, we evaluate the relative significance of three different image features - geometry, moments, and Fourier descriptors in the context of content-based retrieval, and present experimental results. The evaluation metrics are retrieval quality and search time. These could be used …

Community Banking In The E-Business Era, Peter Southard, Keng Siau

Research Collection School Of Computing and Information Systems

This paper reviews how existing and potential uses of Internet technology can generate a competitive advantage for rural community banks. To do so, it offers a framework for analyzing Internet technology investment decisions. Organizations in this segment of the banking industry are often more removed from centers of technology and have traditionally been more conservative in their approaches to information technology (among other things). Banking Associations have developed in the U.S., such as the Independent Bankers Association, to try and help community banks coordinate marketing, legislative, and other issues that they have in common. The use of Internet technology can …

Component-Based Development Using Uml, L. Zhao, Keng Siau

Research Collection School Of Computing and Information Systems

Component-based software development (CBD) is a potential breakthrough for software engineering. Unified Modeling Language (UML) can potentially facilitate CBD design and modeling. Although many research projects concentrate on the conceptual interrelation of UML and CBD, few incorporate actual component frameworks into the discussion, which is critical for real-world software system design and modeling. This paper reviews component-based development, including the use of UML for modeling CBD. The paper then discusses the means by which UML extension mechanisms can be used to better support the popular component framework -- CORBA. Two other important component frameworks, DCOM and Web Services, are also …

Effect Of Tio₂-Mediated Photocatalytic Degradation On The Toxicity Of Orange Ii, Arnaud Eric Nicolas Goutard

Dissertations and Theses @ UNI

C.I. Acid Orange 7 (15510) is the sodium salt of p-[(2-hydroxy-1-naphtalenyl)azo] benzenesulfonic acid. This azo dye is commonly known as Orange II and has been used to dye soaps, shoes, wood and paper (Ramchandani et al., 1994). In the United States and Europe, this dye is not allowed in foodstuffs. The purpose of this study is to investigate the efficiency of a TiO2-mediated photocatalytic oxidation process to degrade Orange II and to determine if Orange II is cytotoxic to certain types of cells. The role of UV radiation and TiO2 particles were examined, as well as the importance of oxygen …

Particle Size Dependent Response Of Aerosol Counters, A. Ankilov, A. Baklanov, M. Colhoun, K. H. Enderle, J. Gras, Yu Julanov, D. Kaller, A. Lindner, A. A. Lushnikov, R. Mavliev, F. Mcgovern, T. C. O'Connor, Josef Podzimek, O. Preining

Physics Faculty Research & Creative Works

During an international workshop at the Institute for Experimental Physics of the University of Vienna, Austria, which was coordinated within the Committee on Nucleation and Atmospheric Aerosols (IAMAS-IUGG), 10 instruments for aerosol number concentration measurement were studied, covering a wide range of methods based on various different measuring principles. In order to investigate the detection limits of the instruments considered with respect to particle size, simultaneous number concentration measurements were performed for monodispersed aerosols with particle sizes ranging from 1.5 to 50 nm diameter and various compositions. The instruments considered show quite different response characteristics, apparently related to the different …

Application Of Artificial Neural Networks To Sensitivity Analysis And Modeling Of Small Office Buildings, Quan Tang

Dissertations and Theses @ UNI

Sensitivity analysis and Multiple Linear Regression (MLR) are the most extensively used techniques in studying the input-output relationship in building thermal systems. However, both MLR and most methods for sensitivity analysis do not account for nonlinear components embedded in building energy systems. Thus, their results might be distorted.

In this study, the Artificial Neural Networks (ANN) technique was applied to sensitivity analysis and modeling of an imaginary small office in order to (a) examine how the annual energy consumption responded to 40 building design parameters and evaluate relative contributions of these parameters to the variation of the building energy performance, …

Large Enhancement Of Spontaneous Emission Rates Of Inas Quantum Dots In Gaas Microdisks, W. Fang, Alexey Yamilov, Yinfa Ma, J. Y. Xu, S. T. Ho, G. S. Solomon, Hui Cao

Physics Faculty Research & Creative Works

Control of spontaneous emission in a microcavity has many important applications, e.g. improvement of the efficiency of light emitting devices. InAs quantum dots (QDs) embedded in microdisks are ideal systems for spontaneous emission control. The whispering gallery (WG) modes of microdisks have low volume and high quality factor. The homogeneous linewidth of InAs quantum dots is smaller than the spectral width of WG modes. Thus, a large enhancement of the spontaneous emission rates should be expected for QDs coupled to WG modes. However, large inhomogeneous broadening of the QD energy levels and random spatial distribution of the QDs in a …

Adaptive Information Filtering: Concepts And Algorithms, Daniel R. Tauritz

Computer Science Faculty Research & Creative Works

Adaptive information filtering is concerned with filtering information streams in dynamic (changing) environments. The changes may occur both on the transmission side — the nature of the streams can change — and on the reception side — the interests of the user (or group of users) can change. While information filtering and information retrieval have a lot in common, this dissertation’s primary concern is with the differences. The temporal nature of information filtering necessitates more flexible document representation methods than does information retrieval where all the occurring terms are known in advance. Also, information filtering typically maintains user interest profiles …

Second-Order Statistical Properties Of The Wss Jakes' Fading Channel Simulator, Chengshan Xiao, Y. Rosa Zheng, N. C. Beaulieu

Electrical and Computer Engineering Faculty Research & Creative Works

An improved Jakes' (1994) fading channel simulator was proposed by Pop and Beaulieu (see ibid., vol.49, p.699-708, Apr. 2001) to eliminate the stationarity problem occurring in Jakes' original design. In this paper, second-order statistical properties of the improved Jakes' simulator are analyzed. Consistent with Pop and Beaulieu's caution about high-order statistics of the simulator, it is proved that some second-order statistics of both the quadrature components and the envelope do not match the desired ones even if the number of sinusoids approaches infinity. Therefore, care must be taken when the simulator is employed to evaluate algorithms and systems.

Quantitative Analysis Of Transmission Power Control In Wireless Ad-Hoc Networks, Seung Jong Park, R. Sivakumar

Computer Science Faculty Research & Creative Works

In this paper, we address the issue of transmission power control in wireless ad-hoc networks. In general, it is assumed that the minimum transmission power required to keep the network connected achieves the optimal throughput performance in an ad-hoc network. In contrast, we show that using the minimal transmission range might not always result in optimal throughput performance. Using both throughput and throughput per unit energy as the optimization criteria, we demonstrate that the optimal transmission power is generically a function of the number of stations, the network size, and the traffic load. In particular, we observe that the optimal …

Node Splitting Algorithms In Tree-Structured High-Dimensional Indexes For Similarity Search, Yongjian Fu, Jui Che Teng, S. R. Subramanya

Computer Science Faculty Research & Creative Works

Content-based searches and retrievals in multimedia and image databases use high-dimensional indexing structures for organizing the features of the objects. Most of those index structures are tree-structured whose nodes have a limit on the number of entries describing the subtrees rooted at those nodes. When index trees are built by repeated insertion of entries, nodes need to be split and the tree balanced accordingly. Node-splitting algorithms eventually determine the final structure of the tree which will have a profound effect on the search performance. This paper presents a comparative study of several node splitting algorithms for a typical high-dimensional indexing …

Using Real Options Analysis For Evaluating Uncertain Investments In Information Technology: Insights From The Icis 2001 Debate, Paul P. Tallon, Robert J. Kauffman, Henry C. Lucas, Andrew B. Whinston, Kevin Zhu

Research Collection School Of Computing and Information Systems

Business and information systems (IS) executives continue to grapple with issues of risk and uncertainty in evaluating investments in information technology (IT). Despite the use of net present value (NPV) and other investment appraisal techniques, executives are often forced to rely on instinct when finalizing IT investment decisions. Recognizing the shortcomings of NPV, real options analysis has been suggested as an alternative approach, one that considers the risks associated with an investment while recognizing the ability of corporations to defer an investment until a later period or to make a partial investment instead. Responding to a growing interest in real …

Dictionary Of 1913 Baseball And Other Lingo, Vol. Ii (G-P), Gerald Leonard Cohen

Arts, Languages and Philosophy Faculty Research & Creative Works

No abstract provided.

Outer Spaces: Lyotard And Feminist Epistemology, Margret Grebowicz

Arts, Languages and Philosophy Faculty Research & Creative Works

No abstract provided.

Old Dominion University Library: History, Jean A. Major

Libraries Faculty & Staff Publications

A history of the library at Old Dominion University, written by Jean A. Major, University Librarian 1992-2002.

Bismuth Triflate Catalyzed Allylation Of Acetals: A Simple And Mild Method For Synthesis Of Homoallyl Ethers, Ram Mohan, Laura Wieland, Herbert Zerth

Scholarship

The allylation of acetals using allyltrimethylsilane is efficiently catalyzed by bismuth triflate (1.0 mol%). The reaction proceeds smoothly at room temperature to afford the corresponding homoallyl ether in good yield. The mild reaction conditions, the low toxicity of bismuth salts, and the high catalytic efficiency of the system make this procedure particularly attractive for large-scale synthesis.

Controlling Web Query Execution In A Web Warehouse, Sanjay Kumar Madria, Sourav S. Bhowmick

Computer Science Faculty Research & Creative Works

Most of the contemporary Web query systems have limited capabilities in controlling Web query execution. Such query facility is important as it gives us an opportunity to optimize the evaluation of a Web query. We address this issue in the context of our Web warehousing system called WHOWEDA (Warehouse Of Web Data). Specifically, we investigate different types of constraints (related to query execution) which may be imposed on a Web query such as number of query results, time of execution, restrict the evaluation of a query to specified set of Web sites, etc. An important feature of our approach is …

A Distributed Discrete-Time Neural Network Architecture For Pattern Allocation And Control, A.T. Chronopoulos, Jagannathan Sarangapani

Computer Science Faculty Research & Creative Works

No abstract provided.