Physical Sciences and Mathematics Commons^™

Design Maintenance In Process Eco-Systems, Tri Kurniawan, Aditya Ghose, Hoa Dam, Lam-Son Le, Tiancheng Zhang

Dr Hoa Dam

This paper addresses the problem of managing business process changes at the design level within a complex business process repository. We argue that a formal process eco-systems view can provide a particular useful solution to the problem in which their inter-process relationships can be properly described. Our intent is to build a modular infrastructure to support change management in process eco-systems by leveraging a change propagation approach that would maintain the inter-process relationships. This permits us to propagate the changes, made on a particular process, to the rest of the processes for maintaining the relationship equilibrium of such eco-system. Our …

Diseñando Colisiones De Satélites En La Guerra Cibernética Encubierta, Jan Kallberg

Jan Kallberg

La guerra concentrada en la red depende de la red de información global para capacidades de combate conjuntas.3 La capa fundamental crea la capacidad de combate global como la columna vertebral espacial de la red de información donde los haberes espaciales son el elemento decisivo. EE.UU. depende de las capacidades espaciales para su éxito y la seguridad nacional de EE.UU. se basa hoy en día en un número limitado de satélites muy utilizados. Estos satélites son cruciales para la disuasión estratégica, la vigilancia, la recopilación de inteligencia y las comunicaciones militares. Si la disuasión estratégica falla, los satélites forman parte …

Privacy Issues And Solutions In Social Network Sites, Xi Chen, Katina Michael

Associate Professor Katina Michael

The boom of the internet and the explosion of new technologies have brought with them new challenges and thus new connotations of privacy. Clearly, when people deal with e-government and e-business, they do not only need the right to be let alone, but also to be let in secret. Not only do they need freedom of movement, but also to be assured of the secrecy of their information. Solove [6] has critiqued traditional definitions of privacy and argued that they do not address privacy issues created by new online technologies. Austin [7] also asserts: “[w]e do need to sharpen and …

Changes In Thermospheric Temperature Induced By High-Speed Solar Wind Streams, Larry Gardner, Jan Josef Sojka, Robert W. Schunk, Rod Heelis

All Physics Faculty Publications

During high-speed stream (HSS) events the solar wind speed increases, and the cross polar cap potential increases, leading to increased Joule heating at high latitudes. The heat input at high latitudes heats the polar regions, which then conducts to lower latitudes, producing global heating. The heating occurs during the risetime of the cross polar cap potential and throughout the period of high cross polar cap potential as seen in our simulation. These simulations are performed using the Utah State University global thermosphere model driven by Joule heating rates that are consistent with electric fields observed by DMSP-15 observations of HSS …

Comparing Theory And Experiment For Analyte Transport In The First Vacuum Stage Of The Inductively Coupled Plasma Mass Spectrometer, Matthew R. Zachreson

Theses and Dissertations

The Direct Simulation Monte Carlo algorithm as coded in FENIX is used to model the transport of trace ions in the first vacuum stage of the inductively coupled plasma mass spectrometer. Haibin Ma of the Farnsworth group at Brigham Young University measured two radial trace density profiles: one 0.7 mm upstream of the sampling cone and the other 10 mm downstream. We compare simulation results from FENIX with the experimental results. We find that gas dynamic convection and diffusion are unable to account for the experimentally-measured profile changes from upstream to downstream. Including discharge quenching and ambipolar electric fields, however, …

Treatment Of A Ring With Periodic Atomic Placement Through Differential Geometry, Gregory Karjala, Lok Lew Yan Voon

Explorations – The Journal of Undergraduate Research, Scholarship and Creativity at Wright State

Most treatments of Bloch’s Theorem have relied on group theory or other mathematical methods for its proof. In this paper we give a derivation of the quantum number first proposed by Y.C Lee and Wei Z. Lee for the Benzene ring through the use of differential geometry. We also develop a Bloch style relationship relation for the benzene ring with an additional quantum number. Through this treatment we show the usefulness of differential geometry in the theorist’s toolkit when it comes to solid-state problems.

Multivariate Data Analysis, Diana Copeland, Michael Raymer

Explorations – The Journal of Undergraduate Research, Scholarship and Creativity at Wright State

The study of biology, computer science, and information technology all combine to form the science of bioinformatics [1]. This field was created to make discoveries on new biological insights [1]. Bioinformatics has several important task one of them being able to analyze and interpret different types of data and this includes multivariate data analysis. Multivariate data analysis can use linear projection methods such as linear discriminant analysis (LDA), principal component analysis (PCA), and projection to latent structures (PLS). I have created a Java program that can manipulate multivariate data by manual rotation and will be comparing my results to the …

Unresolved Question Of The 10he Ground State Resonance, Z. Kohley, J. Snyder, T. Baumann, G. Christian, P.A. Deyoung, J.E. Finck, R.A. Haring-Kaye, M. Jones, E. Lunderberg, B. Luther, S. Mosby, A. Simon, J.K. Smith, A. Spyrou, Sharon L. Stephenson, M. Thoennessen

Physics and Astronomy Faculty Publications

The group state of ¹⁰He was populated using a 2p2n-removal from a 59 MeV/u ¹⁴Be beam. The decay energy of the three body system, 8He + n + n, was measured and a resonance was observed at E = 1.60(25) MeV with a 1.8(4) MeV width. This result is in agreement with previous invariant mass spectroscopy measurements, using the ¹¹Li(-p) reaction, but is consistent with recent transfer reaction results. The proposed explanation that the difference, about 500 keV, is due to the effect of the extended halo nature of ¹¹Li in the one-proton knockout reaction is …

Modeling Radial Bernstein Modes In A Finite-Length Axisymmetric Non-Neutral Plasma, Mark Andrew Hutchison

Theses and Dissertations

Axisymmetric radial Bernstein modes are known to exist in non-neutral plasmas and have been studied theoretically and computationally in 1D, but detection of these modes has still proven to be difficult due to self-shielding. To help advance the work on this front we created a 2D particle-in-cell (PIC) code that simulates a non-neutral plasma in a Malmberg-Penning trap. A detailed description of the PIC code itself has been included that highlights the benefits of using an $r^2$--$z$ grid and how it can be tested. The focus of the PIC simulation was to discover how best to drive and detect these …

The Reasonable Effectiveness Of Mathematics In The Natural Sciences, Nicolas Fillion

Electronic Thesis and Dissertation Repository

One of the most unsettling problems in the history of philosophy examines how mathematics can be used to adequately represent the world. An influential thesis, stated by Eugene Wigner in his paper entitled "The Unreasonable Effectiveness of Mathematics in the Natural Sciences," claims that "the miracle of the appropriateness of the language of mathematics for the formulation of the laws of physics is a wonderful gift which we neither understand nor deserve." Contrary to this view, this thesis delineates and implements a strategy to show that the applicability of mathematics is very reasonable indeed.

I distinguish three forms of the …

Advanced Numerical Methods In General Relativistic Magnetohydrodynamics, Michael J. Besselman

Theses and Dissertations

We show our work to refine the process of evolutions in general relativistic magnetohydrodynamics. We investigate several areas in order to improve the overall accuracy of our results. We test several versions of conversion methodologies between different sets of variables. We compare both single equation and two equations solvers to do the conversion. We find no significant improvement for multiple equation conversion solvers when compared to single equation solvers. We also investigate the construction of initial data and the conversion of coordinate systems between initial data code and evolution code. In addition to the conversion work, we have improved some …

Website Adaptive Navigation Effects On User Experiences, James C. Speirs

Theses and Dissertations

The information search process within a website can often be frustrating and confusing for website visitors. Navigational structures are often complex and multitiered, hiding links with several layers of navigation that user's might be interested in. Poor navigation causes user frustration. Adaptive navigation can be used to improve the user's navigational experience by flattening the navigational structure and reducing the number of accessible links to only those that the user would be interested in. This examines the effects on a user's navigational experience, of using adaptive navigation as the main navigational structure on a website. This study measured these effects …

Telecommunications Network Management Laboratory, I. Raad, Peter James Vial

Dr Peter Vial

This work discusses network management laboratory design and implementation at the University of Wollongong in the School of Electrical, Computer and Telecommunications Engineering in years of 2002 and 2003 for a final year specialisation subject called telecommunication network management for telecommunications engineering students. The design and implementation included that of a network management GUI incorporating the fundamental aspects and functionality of the simple network management protocol (SNMP). The operational code of the SNMP is based on freely available software (joesnmp). This paper outlines how joesnmp was used to develop a suitable network management GUI, which is used to develop laboratory …

Mitagation Against Mai In A Space Time Spreading Software Defined Radio, Shinhan Wee, Montse Ros, Peter Vial

Dr Peter Vial

A Software Defined Radio test bed using the Gnu Radio project was installed on Unix boxes and modified so that estimates of the channel state coefficients were taken for a Multiple Input Multiple output (MIMO) system to take advantage of space time transmission at a frqeuency of 2.4GHz. This system was modified to provide a Space Time Spreading test bed. The test bed was modified so that multiple access interference was experienced by off-setting different users data streams. The Walsh-Hadamard and Wysocki (low correlation) spreading sequences were deployed in the test bed to compare their Bit Error Rate performance. We …

Preliminary Development Of An Inexpensive And Portable Network Monitoring Probe Using An Internet Embedded Microprocessor, Karthic Rajaram, Montse Ros, Peter James Vial

Dr Peter Vial

Management of a telecommunication network involves the requirement to monitor and manage devices on local and wide area networks (for optical, wired and wireless). Devices used to perform this function are referred to as Remote Monitoring devices or network probes. This paper investigates the prototyping of a network probe which uses an embedded internet microprocessor to collect and send data to a network monitor. The device uses the TINI Internet Interface developed by Dallas Semiconductor. This device was chosen as the ethernet driver has a promiscuous mode which potentially allows the capture of all packets sent on the ethernet connection …

Space Time Spreading With Modified Walsh-Hadamard Sequences, Peter James Vial, Beata J. Wysocki, I. Raad, Tadeusz A. Wysocki

Dr Peter Vial

Previous work has shown that the performance of a space time spreading (STS) system using Walsh codes with two transmit antennas at the base station (BS) is degraded in the presence of mutual interference from adjacent sectors in the same cell. We use modified Walsh-Hadamard sequences exhibiting improved cross-correlation performance, which potentially mitigates the effects of MAI (multiple access interference). The presented study also looks at variation of sets of different modified Walsh-Hadamard codes being used by the adjacent interferer, with a hundred randomly selected pairings being chosen, as well as the case where one set of alternate codes is …

On The Effect Of Multiple Access Interference In A Space Time Spreading Time Hopping Ppm Uwb System, Peter Vial, Beata Wysocki, Tadeusz Wysocki, Montserrat Ros, David Stirling

Dr Peter Vial

This study investigates the effect of multiple sources using STS across a Time-Hopping-PPM Modulation that is over an UWB Saleh-Valenzuela channel with each source using two transmit antennas. We model and analyze this system, showing that the presence of such MAI results in a significant degradation in BER performance. Simulation results show that for strong signal strength of interfering MAI signals degradation in BER performance is observed for the cases where we have five and 10 distinct MAI sources present when using Walsh-Hadamard thirty two chip spreading sequences. Using simulation, we investigate the use of other sets of orthogonal spreading …

Design And Simulation Of A Ds-Th-Uwb System Using Simulink/Matlab For First Arriving Rays In A Non Line Of Sight Wireless Scenario, Peter Vial

Dr Peter Vial

An Ultra Wideband system was developed using Simulink in previous work. Using this developed model for Ultra Wideband (UWB) Pulse Position Modulation (PPM) within Simulink, we apply Direct Sequence Walsh codes across Time Hopping Patterns to smooth out the spectral characteristics with Pulse Position Modulation. A non-line of sight Saleh-Valenzuela (SV) model is used to characterize the wireless channel. The system is described and results are presented for the scenario where the first arriving rays are used to detect the transmitted message. For this non-optimum technique (in that for non line of sight the strongest signal rays are available after …

Embedded Internet Laboratory, Fazel Naghdy, Peter Vial, N Taylor

Dr Peter Vial

No abstract provided.

Comparison Of Alamouti And Sts Implementations Using A Software Defined Radio Test Bed, Shinhan Wee, Montserrat B. Ros, Peter James Vial

Dr Peter Vial

A Software Defined Radio test bed using the Gnu Radio project was installed on Unix computers and modified so that estimates of the channel state coefficients were taken for a Multiple Input Multiple output (MIMO) system to take advantage of space time transmission at a frequency of 2.4GHz. Two MIMO techniques were implemented, one based on Alamouti and the other on Space Time Spreading. The technique used to estimate channel coefficients is described. The Bit Error Rate performance was compared, when using Binary Phase Shift Keying, between the two systems and it was found that the STS system performed better …

Telecommunications Network Management Applications In An Educational Environment, Ibrahim Raad, Peter Vial, W. Raad, Keni Popovski

Dr Peter Vial

No abstract provided.

Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins, Tadeusz Wysocki

Dr Le Chung Tran

Quasi-Orthogonal Space-Time-Frequency Codes (QOSTFCs) will be examined in this paper to advance either data rate or error performance in recently proposed Space-Time-Frequency Coded Multiband OFDM Ultra-Wideband (STFC MB-OFDM UWB) communication systems. It is shown that QOSTFCs can provide signi¯cantly better error performance, compared to the conventional MB-OFDM UWB (without STFCs) and to the Orthogonal STFCs (OSTFCs) of the same order, at the same data rate, without increasing the total transmission power. Another form of the enhancement would be that QOSTFCs can provide higher data rates with the same error performance, compared to OSTFCs.

Novel Constructions Of Improved Square Complex Orthogonal Designs For Eight Transmit Antennas, Le Chung Tran, Alfred Mertins, Jennifer Seberry, Tadeusz Wysocki, Sarah Adams

Dr Le Chung Tran

Constructions of square, maximum rate complex orthogonal space–time block codes (CO STBCs) are well known, however codes constructed via the known methods include numerous zeros, which impede their practical implementation. By modifying the Williamson and Wallis-Whiteman arrays to apply to complex matrices, we propose two methods of construction of square, order-4n CO STBCs from square, order-n codes which satisfy certain properties. Applying the proposed methods, we construct square, maximum rate, order-8 CO STBCs with no zeros, such that the transmitted symbols are equally dispersed through transmit antennas. Those codes, referred to as the improved square CO STBCs, have the advantages …

Application Of Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Alfred Mertins, Le Chung Tran

Dr Le Chung Tran

This paper examines the application of Quasi-Orthogonal Space-Time-Frequency Codes (QOSTFCs) to advance either data rate or error performance in recently proposed Space-Time-Frequency Coded Multiband OFDM Ultra-Wideband (STFC MB-OFDM UWB) communications systems. It is shown that QOSTFCs can provide significantly better error performance, compared to the conventional MB-OFDM UWB (without STFCs) and to the Orthogonal STFCs (OSTFCs) of the same order, at the same data rate, without increasing the total transmission power. In other words, QOSTFCs can provide higher data rates with the same error performance, compared to OSTFCs.

Space-Time-Frequency Code Implementation In Mb-Ofdm Uwb Communications: Design Criteria And Performance, Alfred Mertins, Le Chung Tran

Dr Le Chung Tran

This paper proposes a general framework of Space-Time-Frequency Codes (STFCs) for Multi-Band Orthogonal Frequency Division Multiplexing (MB-OFDM) Ultra-Wide Band (UWB) communications systems. A great similarity between the STFC MB-OFDM UWB systems and conventional wireless Complex Orthogonal Space-Time Block Code (CO STBC) Multiple-Input Multiple-Output (MIMO) systems is discovered. This allows us to quantify the pairwise error probability (PEP) of the proposed system and derive the general decoding method for the implemented STFCs. Based on the theoretical analysis results of PEP, we can further quantify the diversity order and coding gain of MB-OFDM UWB systems, and derive the design criteria for STFCs, …

Novel Cooperative Communication Schemes For Space-Time-Frequency Coded Mb-Ofdm Uwb, Le Chung Tran, Xiaojing Huang, Alfred Mertins, Eryk Dutkiewicz

Dr Le Chung Tran

Cooperative communication has been intensively considered for general wireless and sensor networks. However, it has been almost untouched in Space-Time-Frequency Coded Multi-band OFDM Ultra-Wideband (STFC MB-OFDM UWB) systems. This paper thus proposes two cross-layer designs for cooperative communication, namely Simple Cooperative Communication Scheme (SCCS) and Advanced Cooperative Communication Scheme (ACCS), in slow fading scenarios. In the former, nodes always cooperate with one another despite the possibly erroneous reception at the partner nodes, while in the latter, nodes cooperate only in the case of successful reception. Simulations show that these schemes may considerably improve the performance of STFC MB-OFDM UWB without …

Stc-Mimo Block Spread Ofdm In Frequency Selective Rayleigh Fading Channels, Le Chung Tran, Xiaojing Huang, Eryk Dutkiewicz, Joe F. Chicharo

Dr Le Chung Tran

In this paper, we expand the idea of spreading the transmitted symbols in OFDM systems by unitary spreading matrices based on the rotated Hadamard or rotated Discrete Fourier Transform (DFT) matrices proposed in the literature to apply to Space-Time Coded Multiple-Input Multiple-Output OFDM (STC-MIMO-OFDM) systems. We refer the resulting systems to as STC-MIMO Block Spread OFDM (STC-MIMO-BOFDM) systems. In the proposed systems, a multi-dimensional diversity, including time, frequency, space and modulation diversities, can be used, resulting in better bit error performance in frequency selective Rayleigh fading channels compared to the conventional OFDM systems with or without STCs. Simulations carried out …

Unitary Differential Space-Time-Frequency Codes For Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins, E. Dutkiewicz, Xiaojing Huang

Dr Le Chung Tran

In a multiple-input multiple-output (MIMO) multiband orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB) system, coherent detection where the channel state information (CSI) is assumed to be exactly known at the receiver requires the transmission of a large number of symbols for channel estimation, thus reducing the bandwidth efficiency. This paper examines the use of unitary differential space-time frequency codes (DSTFCs) in MB-OFDM UWB, which increases the system bandwidth efficiency due to the fact that no CSI is required for differential detection. The proposed DSTFC MB-OFDM system would be useful when the transmission of multiple channel estimation symbols is impractical or …

Cooperative Communication In Space-Time-Frequency Coded Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins, Tadeusz A. Wysocki

Dr Le Chung Tran

Though cooperative communication has been intensively examined for general wireless systems, such as mobile and ad-hoc networks, it has been almost unexplored in the case of Space-Time-Frequency Coded Multi-band OFDM Ultra-Wideband (STFC MB-OFDM UWB). This paper proposes a framework of cooperative communication in such systems where nodes are equipped with only one antenna. Simulation results show that cooperative communication might, in some cases, provide better error performance than non-cooperative communication without any additional transmission power.

Novel Constructions Of Improved Square Complex Orthogonal Designs For Eight Transmit Antennas, Le Chung Tran, Tadeusz Wysocki, Jennifer Seberry, Alfred Mertins, Sarah Adams

Dr Le Chung Tran

Constructions of square, maximum rate complex orthogonal space-time block codes (CO STBCs) are well known, however codes constructed via the known methods include numerous zeros, which impede their practical implementation. By modifying the Williamson and Wallis-Whiteman arrays to apply to complex matrices, we propose two methods of construction of square, order-4n CO STBCs from square, order-n codes which satisfy certain properties. Applying the proposed methods, we construct square, maximum rate, order-8 CO STBCs with no zeros, such that the transmitted symbols are equally dispersed through transmit antennas. Those codes, referred to as the improved square CO STBCs, have the advantages …