Numerical Analysis and Scientific Computing Commons^™

Signal Processing Design Of Low Probability Of Intercept Waveforms, Nathaniel C. Liefer

Theses and Dissertations

This thesis investigates a modification to Differential Phase Shift Keyed (DPSK) modulation to create a Low Probability of Interception/Exploitation (LPI/LPE) communications signal. A pseudorandom timing offset is applied to each symbol in the communications stream to intentionally create intersymbol interference (ISI) that hinders accurate symbol estimation and bit sequence recovery by a non-cooperative receiver. Two cooperative receiver strategies are proposed to mitigate the ISI due to symbol timing offset: a modified minimum Mean Square Error (MMSE) equalization algorithm and a multiplexed bank of equalizer filters determined by an adaptive Least Mean Square (LMS) algorithm. Both cooperative receivers require some knowledge …

Performance Analysis Of Ieee 802.11b Devices In The Presence Of Interference Aware Scheduling-Adaptive Frequency Hopping Enabled Bluetooth Devices, Deepthi Gopalpet

Electrical & Computer Engineering Theses & Dissertations

Wireless Local Area networks (WLAN) and Wireless Personal Area Networks (WPAN) provide complimentary services using the same unlicensed radio frequency band of operation. The 802.11b WLAN operates in the 2.4 GHz band and uses a Direct Sequence Spread Spectrum technique. It is designed to cover large areas ranging up to 100 meters in diameter, which may connect hundreds of computers. Bluetooth (BT) WPAN also operates in the same frequency band as the IEEE 802.lib and it uses a Frequency Hopping Spread Spectrum technique. BT is primarily used for communications between notebooks, palm units and other personal computing devices within relatively …

Applying The Levels Of Conceptual Interoperability Model In Support Of Integratability, Interoperability, And Composability For System-Of-Systems Engineering, Andreas Tolk, Saikou Y. Diallo, Charles D. Turnitsa

Computational Modeling & Simulation Engineering Faculty Publications

The Levels of Conceptual Interoperability Model (LCIM) was developed to cope with the different layers of interoperation of modeling & simulation applications. It introduced technical, syntactic, semantic, pragmatic, dynamic, and conceptual layers of interoperation and showed how they are related to the ideas of integratability, interoperability, and composability. The model was successfully applied in various domains of systems, cybernetics, and informatics.

Anaerobic Digestion: Decision Support Software, Marco Poliafico

Theses

Ireland has significant quantities of livestock; meat exportation is a vibrant sector of the economy. Environmental management of animal wastes has therefore become an important concern. On the other hand in the last decade, national and EU policy debate has highlighted the need to investigate alternative energy: in particular energy for transport.

This study investigates the quantities of animal wastes produced in Ireland and their potential treatment using Anaerobic Digestion technologies. In 2005 Ireland had over 8 millions animals (cattle and pigs) and the annual slaughter accounted for over 4.2 million of these creatures. These animals have been responsible for …

Finding A Length-Constrained Maximum-Sum Or Maximum-Density Subtree And Its Application To Logistics, Hoong Chuin Lau, Trung Hieu Ngo, Bao Nguyen Nguyen

Research Collection School Of Computing and Information Systems

We study the problem of finding a length-constrained maximum-density path in a tree with weight and length on each edge. This problem was proposed in [R.R. Lin, W.H. Kuo, K.M. Chao, Finding a length-constrained maximum-density path in a tree, Journal of Combinatorial Optimization 9 (2005) 147–156] and solved in O(nU) time when the edge lengths are positive integers, where n is the number of nodes in the tree and U is the length upper bound of the path. We present an algorithm that runs in O(nlog2n) time for the generalized case when the edge lengths are positive real numbers, which …

Strategies For Analysis Of Unimodal And Multimodal Data For Simulation, Anshul Rai Sharma

Electrical & Computer Engineering Theses & Dissertations

The primary objective of this thesis is to provide strategies for analysis for data associated with simulation. Data analysis is an important part of the simulation process. Typically more stress is laid upon the development of the computer simulation while the data analysis takes a back seat. However, the accuracy of a simulation depends on the data driving it. In other words, any simulation is only as accurate as the input data fed into the simulation. Also, the output of simulation should be analyzed properly in order to validly estimate the performance of the system being simulated. The focus of …

Fine-Tuning Of Mass-Spring Model Properties For Simulating Realistic Soft Body Deformation, Sylva A. Girtelschmid

Computational Modeling & Simulation Engineering Theses & Dissertations

Obtaining a well behaved soft-tissue model is one of the most challenging and important tasks in the development of surgical simulation systems. Achieving both accurate and real-time deformation response from a soft-tissue model becomes more difficult as the complexity of the represented anatomy and the degree of deformation increases. One common approach to modeling deformable objects is the Mass-Spring (MS) system method. Mass-Spring systems are attractive to real-time applications due to their relatively low computational requirement and ease of implementation. However, their parameter determination is typically done manually, which becomes tedious when accurate approximation to real-world objects is desired. This …

Numerical Modelling Of Sediments In Cork Harbour, Jérémy Pingon

Theses

In recent years there have been considerable developments in the new and emerging field of hydroinformatics. This relatively new discipline is concerned with the application of computer and networking technology for the planning, management and protection of water bodies.

Environmental issues in estuaries require accurate and detailed knowledge of cohesive sediment transport processes to assess different issues including water quality, pollutant dispersion, and dredging and maintenance of navigation channels.

This thesis presents a review of the main sediment properties and processes required for modelling the behaviour and transport of sediments. It also introduces a new approach to sediment properties using …

Development Of A Systems Engineering Model For Chemical Separation Process, Lijian Sun

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis is concerned with the efforts to develop a general-purpose systems engineering model software TRPSEMPro1 that can be used to improve productivity in the design process. Different features of TRPSEMPro will be presented in this thesis. First, Systems Engineering technology is presented, followed by the exposition of different numerical optimization technologies and DOE (Design of Experiments) study technologies. Second, the detailed software process, Object-Oriented Analysis and Design (OOA&D) for the TRPSEMPro is presented. All the design data models are expressed by using Unified Modeling Language (UML).

AMUSESimulator is another software package which has been designed and implemented in order …

Process Flow Optimization Studies Through Discrete Event Simulation, Milind Chokshi

Electrical & Computer Engineering Theses & Dissertations

Computer-aided simulation has begun to emerge as a powerful tool for numerical analysis of the behavior and anticipated performance of industrial systems and their optimization. Applications include materials handling, storage and controls systems, prediction of manufacturing efficiencies, and production optimization. Simulations are used to test baseline models and subsequently analyze new production concepts, operating strategies, and planned procedures prior to costly implementation.

The study of process flows in a manufacturing environment is difficult due to its inherent stochastic nature. Breakdown of the sub-systems and failures of machines is a random process and needs to be solved based on concepts of …

Monte Carlo Simulations Of Photoemission Characteristics From Gaas And Diamond, Abhishek Srivastava

Electrical & Computer Engineering Theses & Dissertations

Monte Carlo based numerical simulations were performed to study photoemission from GaAs and diamond. The central goal was to assess the potential for NEA photoemission from diamond, and to predict its characteristics. The GaAs material system was also included in the simulation study to provide: (i) calibration and validation of the numerical model developed by carefully matching the simulation results with available experimental data, and (ii) quantitative comparisons between the response characteristics of diamond and the better known GaAs system.

Predictions of the energy distribution, temporal response and angular distribution of emitted electrons were obtained. Effects of various parameters, such …

On The Complexity Of Manpower Shift Scheduling, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

We consider the shift assignment problem in manpower scheduling, and show that a restricted version of it is NP-hard by a reduction from 3SAT. We then present polynomial algorithms to solve special cases of the problem and show how they can be deployed to solve more complex versions of the shift assignment problem. Our work formally defines the computational intractibility of manpower shift scheduling and thus justifies existing works in developing manpower scheduling systems using combinatorial and heuristic techniques.

Optimal Mixed-Norm Control Synthesis For Discrete-Time Linear Systems, David R. Jacques

Theses and Dissertations

A mixed-norm approach to control synthesis for discrete time linear systems is developed. Specifically, the problem of minimizing the H₂ norm of a transfer function, subject to a combination of ℓ₁ and-or H_∞ norm constraints on dissimilar but related transfer functions is considered. The uniqueness of the optimal solution is shown, and numerical methods for approximating the optimal solution to within arbitrary accuracy are developed. These methods generally result in high order compensators which can not be implemented in most practical applications. In response to this, a numerical method is developed which solves for suboptimal solutions of …

Multirate Time-Frequency Distributions, John R. O'Hair

Theses and Dissertations

Multirate systems, which find application in the design and analysis of filter banks, are demonstrated to also be useful as a computational paradigm. It is shown that any problem which can be expressed a set of vector-vector, matrix-vector or matrix-matrix operations can be recast using multirate. This means all of numerical linear algebra can be recast using multirate as the underlying computational paradigm. As a non-trivial example, the multirate computational paradigm is applied to the problem of Generalized Discrete Time- Frequency Distributions GDTFD to create a new family of fast algorithms. The first of this new class of distributions is …

A Numerical Study Of High-Speed Missile Configurations Using A Block- Structured Parallel Algorithm, Douglas C. Blake

Theses and Dissertations

A numerical analysis of the aerodynamic phenomena associated with the high-speed flight of a sharp-nosed, four-finned, high-fineness ratio missile using a block-structured, parallel computer algorithm is presented. The algorithm, PANS-3EM, utilizes a second-order-accurate, shock-capturing, Total Variation Diminishing scheme and incorporates a Baldwin-Lomax turbulence model. PANS-3EM allows for extreme flexibility in the choice of computational domain decomposition and computing machine of implementation. Developmental work consists of conceptualization and verification of the algorithm as well as parallel performance and scalability studies conducted on a variety of computing platforms. Using PANS-3EM, the aerodynamic characteristics of the missile are investigated. Drag and pitching moment …

Shadow Casting Phenomena At Newgrange, Frank Prendergast

Articles

A digital model of the Newgrange passage tomb and surrounding ring of monoliths known as the Great Circle is used to investigate sunrise shadow casting phenomena at the monument. Diurnal variation in shadow directions and lengths are analysed for their potential use in the Bronze Age to indicate the passage of seasonal time. Computer-aided simulations are developed from a photogrammetric survey to accurately show how three of the largest monoliths, located closest to the tomb entrance and archaeologically coded GC1, GC-1 and GC-2, cast their shadows onto the vertical face of the entrance kerbstone, coded K1. The phenomena occur at …

A Direct Formulation And Computer-Implementation Of A Symbolic Network Analysis Algorithm, Timothy James Knerr

Electrical & Computer Engineering Theses & Dissertations

An algorithm for the symbolic analysis of linear, time-invariant, active or passive networks is presented. The algorithm incorporates the best features of earlier numerical and topological methods of symbolic analysis. A hybrid set of equations is formulated for a closed linear graph and arranged in matrix form. A numerical evalu­ation procedure for the determinant of this hybrid matrix results in an efficient method of symbolic analysis. A proof of the algorithm based on determinant evaluation by a permutation product expansion provides insight into relationships with other methods of symbolic analysis. A computer program implementation of the algorithm is described and …

Digital Computer Solution Of Electromagnetic Transients In Large Power Systems, Bijan Navidbakhsh

Dissertations and Theses

This thesis is an introduction to the solution of electromagnetic transients by a combination of the Bergeran method of characteristics and the application of trapezoidal rule of integration.

Three test examples solved by digital computer illustrate the step by step solution and computer programming.

To compare this method with the Laplace transformation technique, a test problem solved by both methods and also digital computer is illustrated. In conclusion, the advantages and disadvantages of both methods are compared.