Neelakanta, Perambur S.

This thesis addresses a method of deducing the statistical upper and lower bounds associated with the cell-transfer delay variations (CDVs) encountered by the cells transmitted in the asynchronous transfer mode (ATM) networks due to cell losses. This study focuses on: (1) Estimating CDV arising from multiplexing/switching for both constant bit rate and variable bit rate services via simulations. (2) Deducing an information-theoretics based new technique to get an insight of the combined BER-induced and multiplexing/switching-induced CDVs in ATM networks. Algorithms on the CDV statistics are derived and the lower and upper bounds of the statistics are obtained via simulations in respect of CBR and VBR traffics. These bounds bounds are useful in the cell-admission control (CAC) strategies adapted in ATM transmissions. Inferential remarks indicating the effects of traffic parameters (such as bandwidth, burstiness etc.) on the values of the statistical bounds are presented, and scope for further work is indicated.

This thesis refers to a research addressing the use of information-theoretic techniques in optimizing an artificial neural network (ANN) via a genetic selection algorithm. Pertinent studies address emulating relevant experiments on a test ANN (based on Hopfield's associative memory model) wherein the said optimization is tried with different sets of control parameters. These parameters include a new entity based on the concept of entropy as conceived in the field of information theory. That is, the mutual entropy (Shannon entropy) or information-distance (Kullback-Leibler-Jensen distance) measure between a pair of candidates is considered in the reproduction process of the genetic algorithm (GA) and adopted as a selection-constraint parameter. The research envisaged further includes a comparative analysis of the test results which indicate the importance of proper parameter selection to realize an optimal network performance. It also demonstrates the ability of the concepts proposed here in developing a new neural network approach for pattern recognition problems.

This thesis is concerned with an outline survey on the modern aspects of asynchronous transmission mode (ATM) telecommunication; also considered are certain specific issues such as the performance characteristics of ATM-based telecommunication networks under fluctuating workloads. Estimation of the stochasticity of the jitter associated with the cell-delay arising out of buffering within the network as well as due to signal-to-noise considerations which induce bit-errors and eventually lead to cell-losses manifesting as delay(s) in the cells being transmitted, is also addressed as a part of this thesis efforts. Relevant theoretical models are proposed, algorithms are developed and simulations are done on the above considerations. Based on these efforts, inferential conclusions are drawn and discussed. Scope for future research and developments towards engineering design of softwares suitable for practical applications by ATM networking planners and traffic forecasters is indicated. Merits and shortcomings of the models are proposed and algorithmic approaches pursued in the present study are also specified with relevant discussions.

Most infrared based target-seeking systems operate as passive detectors of the target with no energy being required to be transmitted from the seeker in order to detect a target. Reticles are used commonly in these passive homing seekers to modulate the incoming radiation from the target. Since signals are invariably corrupted by noise, the analysis of signal-to-noise characteristics of a passive homing system is crucial in elucidating its performance towards successful homing on the target. The objective of this thesis refers to the analysis of a passive homing system which employs a frequency modulated reticle. Studies pertinent to the feasibility aspect of using electrochromic, nonmoving reticles also constitute a part of the present study. In essence, the effort addressed in this work are concerned with the performance analysis and feasibilities considerations in using nonmoving reticles in passive homing systems in lieu of conventional rotating reticles.

This Thesis is concerned with the application of stochastical mixture considerations in the analytical modeling of certain classes of electromagnetic composites. It refers to the elucidation of the electromagnetic properties of such composite materials when used in engineering applications. The analytical studies refer to the extension of the existing stochastical mixture permittivity formulations to characterize magnetic mixture materials as well as chiralic mixture media. In both cases the mixture medium is presumed to consist of a host (receptacle) and dispersed particulates (inclusions). The effects of particulate shape in both chiralic and achiralic systems are also considered. Further, the concept of particulate polarization in deciding the permittivity and/or permeability characteristics of orderly-textured mixture media is addressed so as to determine the electromagnetic properties of such orderly-textured media. Application potentials of the present studies in the design of electromagnetic composites are indicated and the scope for the future research is portrayed.

This thesis is concerned with the measurement of magnetic field components induced above the earth's surface by three classes of high-voltage power transmission lines supplemented by algorithmic formulations: The first system refers to three-phase lines housed in a plastic (PVC) conduit, buried directly in the soil or encased in a concrete duct. The second category refers to a similar buried system, but encased in an iron/steel pipe. The third transmission line is an overhead three-phase system. Using boundary-value approach, approximate (closed-form) expressions are obtained for the magnetic field above the earth's surface caused by each of the systems indicated. Calculated results are compared with experimental data compiled from field experiments.

This thesis is concerned with the evaluation of radar detection performance specific to the following target and background considerations: (1) Stochastical description and determination of the envelope statistics pertaining to radar clutter of the coastline regions. (2) Detection of low-altitude targets by sea-borne radars operating near the coastline; and (3) Fractal characterization of the ocean surface as viewed by a satellite-based radar altimeter. The first problem refers to the elucidation of the most appropriate statistics that would describe the relevant envelope distribution of the clutter caused by the dual region of sea and land of a typical coastline environment. In the second analysis, performance of the radar in terms of false-alarm and detection probabilities is predicted. The third effort addressed provides a fractal description of the ocean surface as viewed by a satellite based radar altimeter. By characterizing the ocean bed as a fractal surface, the extent to which the sea surface data contributes errors to the mispointing/autoboresight information is ascertained.

A promising next-generation version of service that could be availed from local exchange carriers (LECs) refers to streaming Internet protocol based television (IPTV) programs into subscriber premises via traditional copper pairs. The present study addresses provisioning economically-budgeted and optimally-engineered bit rates (EBRs) in implementing IPTV technology in the local-loop via copper-pairs using the so-called (ADSL2/ADSL2+) technology (with high-speed/large bandwidth considerations plus copper-bonding for bandwidth sharing capabilities). Also studied is the way to extend the backhaul transport of IPTV on copper-lines (plus any other local-loop transmissions that may co-exist) onto an "all-optical" trunk of the inter-office facilities (IOFs) in the edge/core network cloud of the telcos. A model of a core network topology is analyzed for traffic considerations so as to decide on blocking probability at a specified egress node under different conditions of burstiness. The problems posed are analyzed via computations/simulations on Matlab(TM) (v6.5). Inferential remarks are gathered, conclusions are drawn and open-questions yet to be researched are indicated.

Sorensen's model of glucose metabolism and regulation is reconstructed using SimulinkRTM. Most of the existing glucose metabolism models consist of several mass balance equations that interact with each others. Graphical format used by SimulinkRTM provides a visualized perspective of such relations so that it is easier to modify the model on ad hoc basis. Type-I and Type-II diabetes with relevant clinical details are simulated. Further, a control strategy is introduced in order to simulate the control of exogenous insulin pump. Simulated results are consistent with available clinical data. Living systems in general, exhibit both stochastical and deterministic characteristics. Activities such as glucose metabolism traditionally modeled do not include stochastical properties, nor that they are viewed in the large framework of complex system with explicit interaction details. Currently, a complexity system model is developed to describe the glucose metabolism related activities. The simulation results obtained thereof illustrate the bounding domain of variations in some clinically observed details.

This thesis refers to a research addressing the use of binary representation of the DNA for the purpose of developing useful algorithms for Bioinformatics. Pertinent studies address the use of a binary form of the DNA base chemicals in information-theoretic base so as to identify symmetry between DNA and complementary DNA. This study also refers to "fuzzy" (codon-noncodon) considerations in delinating codon and noncodon regimes in a DNA sequences. The research envisaged further includes a comparative analysis of the test results on the aforesaid efforts using different statistical metrics such as Hamming distance Kullback-Leibler measure etc. the observed details supports the symmetry aspect between DNA and CDNA strands. It also demonstrates capability of identifying non-codon regions in DNA even under diffused (overlapped) fuzzy states.