Physical Sciences and Mathematics Commons^™

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

Faculty of Informatics - Papers (Archive)

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

Faculty of Informatics - Papers (Archive)

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 …

Singular Value Decomposition In Image Noise Filtering And Reconstruction, Tsegaselassie Workalemahu

Mathematics Theses

The Singular Value Decomposition (SVD) has many applications in image processing. The SVD can be used to restore a corrupted image by separating significant information from the noise in the image data set. This thesis outlines broad applications that address current problems in digital image processing. In conjunction with SVD filtering, image compression using the SVD is discussed, including the process of reconstructing or estimating a rank reduced matrix representing the compressed image. Numerical plots and error measurement calculations are used to compare results of the two SVD image restoration techniques, as well as SVD image compression. The filtering methods …

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

Faculty of Informatics - Papers (Archive)

Space-Time-Frequency Codes (STFCs), which haverecently been proposed in the literature for Multiband OFDMUltra-Wideband (MB-OFDM UWB) systems to improve thesystem capacity, error performance and wireless communicationrange, are all constructed based on orthogonal structures. Thispaper examines the application of Quasi-Orthogonal STFCs(QOSTFCs) to enhance further either data rate or error performancein the recently proposed STFC MB-OFDM UWB systems.It will be shown that QOSTFCs can provide significantly bettererror performance, compared to the conventional MB-OFDMUWB (without STFCs) as well as to the Orthogonal STFCs(OSTFCs) of the same order, at the same data rate, withoutincreasing the total transmission power. Equivalently, QOSTFCscan provide higher data rates with …

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

Faculty of Informatics - Papers (Archive)

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.

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

Faculty of Informatics - Papers (Archive)

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.

Direct Imaging Of Lipid-Ion Network Formation Under Physiological Conditions By Frequency Modulation Atomic Force Microscopy, Michael J. Higgins, Suzi P. Jarvis, Takeshi Fukuma

Faculty of Science - Papers (Archive)

Various metal cations in physiological solutions interact with lipid headgroups in biological membranes, having an impact on their structure and stability, yet little is known about the molecular-scale dynamics of the lipid-ion interactions. Here we directly investigate the extensive lipid-ion interaction networks and their transient formation between headgroups in a dipalmitoylphosphatidylcholine bilayer under physiological conditions. The spatial distribution of ion occupancy is imaged in real space by frequency modulation atomic force microscopy with sub-Angstrom resolution.

Electrochemical Characteristics Of A 7-Ferrocenyl(Carbonyloxy)-1- Heptanethiol-Modified Gold Electrode, Mohammed Muzibur Rahman, Il Cheol Jeon

Turkish Journal of Chemistry

The electrochemical properties of 7-ferrocenyl(carbonyloxy)-1-heptanethiol [FcCO_2(CH_2)_7SH] were characterized by an electrochemical quartz crystal microbalance (EQCM). A gold surface was modified with FcCO_2(CH_2)_7SH by the self-assembly method. EQCM was used to investigate mass change during the redox reactions of FcCO_2(CH_2)_7SH monolayers on a modified gold electrode in solution containing K_3Fe(CN)_6 redox species. The FcCO_2(CH_2)_7SH monolayer on gold acts as a mediator for the electron transfer between a gold electrode and electroactive species Fe(CN)_6^{3-/4-} in solution. In both cases, electrochemical current responses were complicated because the observed currents were due to the redox of both the ferrocenyl group immobilized on gold and …

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

Faculty of Informatics - Papers (Archive)

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 …

A New Approach For Anti-Aliasing Raster Data In Air Borne Imagery, Fahim Arif, Muhammad Akbar

International Conference on Information and Communication Technologies

Air borne sensed data is in the form of raster data. Aliasing is always present in a sampled image causing artifact error. To reduce possible aliasing effects, it is a good idea to blur an image slightly before applying a resampling method on it. This paper presents a technique for anti-aliasing remotely sensed images. The technique uses Gaussian low pass filter (GLPF) for generation of slight blur. Then resampling of raster data is performed with the help of bilinear interpolation. Algorithm is developed in MATLAB using some inbuilt functions.

The Effect Of Inharmonic Partials On Pitch Of Piano Tones, Brian E. Anderson, William J. Strong

Faculty Publications

Piano tones have partials whose frequencies are sharp relative to harmonic values. A listening test was conducted to determine the effect of inharmonicity on pitch for piano tones in the lowest three octaves of a piano. Nine real tones from the lowest three octaves of a piano were analyzed to obtain frequencies, relative amplitudes, and decay rates of their partials. Synthetic inharmonic tones were produced from these results. Synthetic harmonic tones, each with a twelfth of a semitone increase in the fundamental, were also produced. A jury of 21 listeners matched the pitch of each synthetic inharmonic tone to one …

Response Of Mains Connected Induction Motors To Low Frequency Voltage Fluctuations From A Flicker Perspective, Sankika Tennakoon, Sarath Perera, D A. Robinson

Faculty of Informatics - Papers (Archive)

In radial power systems flicker transfer from a higher voltage level (upstream) to a lower voltage level (downstream) is seen to be significantly affected by the downstream load composition. Industrial load bases containing mains connected induction motors are known to be effective in the flicker attenuation process compared to residential load bases containing passive loads. For better understanding of the flicker attenuation influenced by induction motors their dynamic behaviour has to be closely investigated under fluctuating supply conditions. This paper presents the methodology and results of investigations undertaken to examine the response of an induction motor to small perturbations in …

Multi-Frequency And Multiple Phase-Shift Sinusoidal Fringe Projection For 3d Profilometry, Enbang Li, X. Peng, Jiangtao Xi, Joe F. Chicharo, Jianquan Yao, D.W. Zhang

Faculty of Informatics - Papers (Archive)

In this paper, we report on a laser fringe projection set-up, which can generate fringe patterns with multiple frequencies and phase shifts. Stationary fringe patterns with sinusoidal intensity distributions are produced by the interference of two laser beams, which are frequency modulated by a pair of acousto-optic modulators (AOMs). The AOMs are driven by two RF signals with the same frequency but a phase delay between them. By changing the RF frequency and the phase delay, the fringe spatial frequency and phase shift can be electronically controlled, which allows high-speed switching from one frequency or phase to another thus makes …

Background Radio Frequency Interference Measurements For Wireless Devices In The Electricity Supply Industry, D A. Robinson, Tadeusz A. Wysocki, Victor W. Smith, Keni Popovski

Faculty of Informatics - Papers (Archive)

Incorporation of radio controller units into heavy equipment used in the electricity industry provides numerous advantages including: improved electrical isolation between plant and operator, ability to incorporate an additional remote operator, and reductions in vehicle wiring and hydraulic hoses for equipment control. However, secure operation of vehicles and plant incorporating radio control rely on establishing suitable levels of immunity to possible radio frequency interference. Interference levels in close proximity to high voltage power lines are of special concern to the electricity industry. This paper reports on a preliminary investigation into quantifying the levels of background radio interference at such locations …

Network Intrusion Detection: Monitoring, Simulation And Visualization, Mian Zhou

Electronic Theses and Dissertations

This dissertation presents our work on network intrusion detection and intrusion sim- ulation. The work in intrusion detection consists of two different network anomaly-based approaches. The work in intrusion simulation introduces a model using explicit traffic gen- eration for the packet level traffic simulation. The process of anomaly detection is to first build profiles for the normal network activity and then mark any events or activities that deviate from the normal profiles as suspicious. Based on the different schemes of creating the normal activity profiles, we introduce two approaches for intrusion detection. The first one is a frequency-based approach which …

Quantitative Force Measurements In Liquid Using Frequency Modulation Atomic Force Microscopy, Suzi P. Jarvis, S. Akita, Takayuki Uchihashi, John E. Sader, Y. Nakayama, Michael J. Higgins, S Yasuda

Faculty of Science - Papers (Archive)

The measurement of short-range forces with the atomic force microscope (AFM) typically requires implementation of dynamic techniques to maintain sensitivity and stability. While frequency modulation atomic force microscopy (FM-AFM) is used widely for high-resolution imaging and quantitative force measurements in vacuum, quantitative force measurements using FM-AFM in liquids have proven elusive. Here we demonstrate that the formalism derived for operation in vacuum can also be used in liquids, provided certain modifications are implemented. To facilitate comparison with previous measurements taken using surface forces apparatus, we choose a model system (octamethylcyclotetrasiloxane) that is known to exhibit short-ranged structural ordering when confined …

Nonlinear Sigma Model For Odd-Frequency Triplet Superconductivity In Superconductor/Ferromagnet Structures, J E. Bunder, K B. Efetov

Faculty of Informatics - Papers (Archive)

No abstract provided.

Maintaining Stability With Distributed Generation In A Restructured Industry, Judith Cardell, Marija Ilic

Engineering: Faculty Publications

A set of reduced order, linearized, dynamic models for distributed generators is developed along with a framework for modeling the generators in a power distribution system. Analysis of this distributed system structure raises two issues. The first is that the simulations demonstrate, unexpectedly, that a small load disturbance is capable of causing frequency instability in the primary dynamics of the distributed generators. Eigenanalysis of the instability suggests that it is a system phenomenon. The second issue is that the system matrix is found to not have a block diagonal dominant structure raising questions over the possible implementation of decentralized control …

Large Dielectric Constant And Maxwell-Wagner Relaxation In Bi2/3cu3ti4o12, Jianjun Liu, Chun-Gang Duan, Wei-Guo Yin, Wai-Ning Mei, Robert W. Smith, John R. Hardy

Physics Faculty Publications

We studied frequency and temperature dependences of impedance, electric modulus, and dielectric permittivity of Bi2/3Cu3Ti4O12 in the ranges of 10−1–106 Hz and −150–200 °C, respectively. We first observed two electrical responses in the impedance and modulus formalisms. Then we detected a Debye-like relaxation in the permittivity formalism. Most interestingly, we found that the large dielectric constant of Bi2/3Cu3Ti4O12 is independent of the temperature and frequency below 150°C. The results are interpreted in terms of a two-layer model with conducting grains partitioned from each other by poorly conducting grain boundaries. Using this model, we attributed the two electrical responses in impedance …

Dielectric Permittivity And Electric Modulus In Bi2ti4o11, Jianjun Liu, Chun-Gang Duan, Wei-Guo Yin, Wai-Ning Mei, Robert W. Smith, John R. Hardy

Physics Faculty Publications

Frequency and temperature dependences of dielectric permittivity and electric modulus of pure and Ba-doped Bi2Ti4O11 were studied in the ranges of 1021–106 Hz and 2150–350 °C, respectively. We found that the antiferroelectric phase transition temperature of Bi2Ti4O11 decreases with Ba doping. In the permittivity studies, we also observed dielectric relaxation peaks shift to higher temperature with increasing frequency. Furthermore, in the electric modulus formalism, conducting peaks were uncovered above 150 °C in addition to the dielectric relaxation peak. We discussed the mechanisms for the dielectric relaxation and conduction processes based on TiO6 octahedra distortion and a space-charge model.

Where To Sit? A Look At Frequency's Effect On Volume Distribution In The Singletary Concert Hall, Matthew Williams

Kaleidoscope

The objective of this project was to find the best seat in the Concert Hall of the Singletary Center for the Arts, here at the University of Kentucky. While subjective factors often determine a patron's favorite place to sit, I decided that an objective scientific approach could prove useful when I, or anyone, next attended a concert. Using only a keyboard amplified by speakers placed at center stage and a sound level monitor, I measured separately the volume of six different frequencies (at intervals of an octave) at twelve different seats throughout the Hall. Defining the best seat as the …

Multi-Level Modeling Of Software On Hardware In Concurrent Computation, Joann M. Paul, Arne Suppe, Henele I. Adams, Donald E. Thomas

Research Collection School Of Computing and Information Systems

The fundamental modeling differences between hardware and software modeling can be thought of as reasoning about connectedness vs. reasoning about interleaved (shared) access to resources. A natural design hierarchy for physical systems is component-based because of the existence of a consistent basis for interconnect between design levels. However, performance modeling and design of concurrent, programmable systems require new ways of thinking about what it means to abstract detail, add detail and partition a model of software executing on hardware. We motivate frequency interleaving (FI) as a common simulation foundation for these systems because it resolves flow and partitioning with software …

Environmental Impacts: The Dark Side Of Outdoor Recreation?, Scott G. Miller

Outdoor Recreation: Promise and Peril in the New West (Summer Conference, June 8-10)

14 pages.

Contains 4 pages of references.

Droplet Evaporation And Deformations In An Amplitude Modulated Ultrasonic Field, Nihad E. Daidzic, Rene Stadler, Adrian Melling

Aviation Department Publications

The aim of the report presented is the measurements of droplet oscillations.

Connectionist Expert System With Adaptive Learning Capability, B. T. Low, Hochung Lui, Ah-Hwee Tan, Hoonheng Teh

Research Collection School Of Computing and Information Systems

A neural network expert system called adaptive connectionist expert system (ACES) which will learn adaptively from past experience is described. ACES is based on the neural logic network, which is capable of doing both pattern processing and logical inferencing. The authors discuss two strategies, pattern matching ACES and rule inferencing ACES. The pattern matching ACES makes use of past examples to construct its neural logic network and fine-tunes itself adaptively during its use by further examples supplied. The rule inferencing ACES conceptualizes new rules based on the frequencies of use on the rule-based neural logic network. A new rule could …

Van Der Waals Interactions Of Carbon Monoxide, Gregory A. Parker, Russell T. Pack

Faculty Publications

Pade approximant methods and experimental frequency dependent polarizabilities are used to calculate reliable van der Waals C6 coefficients for the interaction of CO with He, Ne, Ar, Kr, Xe, H, Li, Na, K, Rb, Cs, H2, N2, O2, CO2, and CO. Error bounds are given for the C6 coefficients and for the CO oscillator strength sums.