Digital Commons Network^™

Photonics In Switching, Harvard S. Hinton

Electrical and Computer Engineering Faculty Publications

One of the keys to the future of telecommunications companies will be their ability to provide new broadband services to both the business community and residential customers. With the new services will come the need for the equivalent of a broadband switching office. Such a system could require the capability of supporting in excess of 10000 users with broadband channel bit rates exceeding 100 Mb/s. This implies a switching fabric the aggregate bit rate of which could be greater than 1 Tb/s. Guided-wave technology and free-space technology switching fabrics are discussed. Three time-division-based switching fabrics are proposed, and two wavelength-division-based …

Switching To Photonics, Harvard S. Hinton

Electrical and Computer Engineering Faculty Publications

The use of hardware that exploits the interplay of photons and electrons to switch voice, data, and video is discussed. The two directions being taken by current research-guided-wave and free-space photonics-are examined. Photonic time-slot interchanges are described. Multidivisional fabrics, based on a combination of space-division and time-division multiplexing, are considered, as is the wavelength-division-based photonic packet switch, another kind of multidimensional fabric. The use of self-electrooptic effect devices, (SEEDs) is discussed.

All-Optical Synchronisation And Multiplication Of The Frequency Of Mode-Locked Signals, P. Phelan, Gerald Farrell, Joe Hegarty

Articles

We report all-optical synchronized multiplication by rational fractions of the modulation frequency of optical signals in self-pulsing two-section semiconductor laser diodes. The effect is based on the overlap of harmonics of the input signal with harmonics of the self-pulsation. We illustrate this new generic function with modelocked inputs rich in harmonics were fractions of 1,2, and 3 / 2 are generated, and we identify a number of applications for this effect.

A Demonstration Of Machine Control Using The Slc-150 Microprocessor Programmable Controller, Mike Courts, Richard Schmitz

Graduate Student Work

This project will use an Allen-Bradley SLC-150 microprocessor programmable controller to demonstrate an actual application being used in industry. The SLC-150 will be used to sequentially control a Pelco pan and tilt drive unit. This unit is mounted with a video camera that is used for security monitoring. The SLC-150 will also control the cameras zooming features.

Prior to microprocessors the electrical control of machines used input devices such as push buttons and limit switches connected to magnetically hard wired relay logic. Hard wiring meant that electrical wires were connected between all relay coils and contacts, making up what is …

Coperite-Computer-Aided Tool For Power Engineering Research, Instruction, Training And Education, Badrul H. Chowdhury, D. E. Clark

Electrical and Computer Engineering Faculty Research & Creative Works

A graphics-oriented, primarily PC-based tool for education, research, and training in power engineering is introduced. The tool, called COPERITE, has all user interfaces resident on an IBM-386 microcomputer. Menus and windows are used for the interface, and attractive graphical representations and displays are included. Application programs that are interfaced are power flow, contingency analysis, economic dispatch, security-constrained dispatch, system stability, and fault analysis. These programs are executed on a VAX 8800 computer mainly for speed of execution. Information exchange between the PC and the VAX is made through an Ethernet connection which is transparent to the user. Results of execution …

Principal Linear Polarization States Of An Optical System, R. M.A. Azzam

Electrical Engineering Faculty Publications

The constraint on the Jones matrix of an optical system such that there exist two linear polarization states at its input that are mapped onto two corresponding linear states at its output is derived. These principal linear polarization (PLP) states, which characterize a broad range of systems, are also found in terms of the Jones matrix elements. Special cases when the PLP states are orthogonal, collapse onto one state, or become infinite in number are indicated. For a deterministic or nondeterministic optical system described by a Mueller matrix, the existence of two PLP states places a constraint on only 3 …

Characterizations Of Antimony Tri‐Sulfide Chemically Deposited With Silicotungstic Acid, O. Savadogo, K. C. Mandal

Faculty Publications

No abstract provided.

Object-Based Analog Vlsi Vision Circuits, C. Koch, B. Mathur, S. C. Liu, J. G. Harris, J. Luo, M. Sivilotti

Electrical and Computer Engineering Faculty Research & Creative Works

Early vision algorithms typically can be classified as either pixel-based or image-based. Pixel-based algorithms such as edge detection and optical flow produce a dense output on every grid point. Image-level algorithms such as center of mass computation [1,5] produce a few outputs by integrating information from the entire image. Most special-purpose analog VLSI vision chips developed so far implement early vision algorithms of these categories. Little work has been done in building special-purpose chips that move beyond these early-vision algorithms. Dynamic wires, first introduced by Liu and Harris [2], provide an avenue for object-based processing. The dynamic wire model is …

Efficient Simulation Of Multi-Carrier Digital Communication Systems In Nonlinear Channel Environments, K. W. Schneider, William H. Tranter

Electrical and Computer Engineering Faculty Research & Creative Works

For systems that contain both frequency division multiplexing and bandpass nonlinearities, the high sampling rate that is necessary for accurate simulation contributes to the long runtimes. A partial sum of products (ParSOP) method is proposed to reduce the sampling rate of such systems. The ParSOP method allows the simulation sampling frequency to be reduced by only generating those intermodulation products that are centered in the bandwidth of the single observed modulated subcarrier. Simulation results, obtained by using the complex power series nonlinear model on a filtered binary phase shift keying system, showed that a reduction in the simulation runtime by …

The Error Probability Of Reed-Solomon Coding And Interleaving On A Bursty-Noise Channel, W. J. Ebel, William H. Tranter

Electrical and Computer Engineering Faculty Research & Creative Works

A useful bursty-noise channel model is proposed and, using this model, a binary communication system using Reed-Solomon coding and interleaving is analyzed. The model includes both thermal noise, which gives rise to random errors, and burst noise, which gives rise to error bursts. Error probabilities are derived for the uncoded system, and error probability bounds are derived for the coded system. Monte Carlo simulation results agree well with theory.

All Optical Clock Distribution With Synchronous Frequency Division And Multiplication, Gerald Farrell, P. Phelan, Joe Hegarty

Articles

A master optical clock from a mode locked laser is distributed to two slave twin section lasers. One slave laser divides the optical modulation frequency by 2, the other slave laser multiplies the frequency by 2. It is also possible to vary the multiplication4ivision ratio in a slave laser using only DC control of the absorber of the twin section laser.

A Generalized, Parametric Pr-Qmf/Wavelet Transform Design Approach For Multiresolution Signal Decomposition, Hakan Caglar

Dissertations

This dissertation aims to emphasize the interrelations and the linkages of the theories of discrete-time filter banks and wavelet transforms. It is shown that the Binomial-QMF banks are identical to the interscale coefficients or filters of the compactly supported orthonormal wavelet transform bases proposed by Daubechies.

A generalized, parametric, smooth 2-band PR-QMF design approach based on Bernstein polynomial approximation is developed. It is found that the most regular compact support orthonormal wavelet filters, coiflet filters are only the special cases of the proposed filter bank design technique.

A new objective performance measure called Non-aliasing Energy Ratio(NER) is developed. Its merits …

A Graphical Tool For The Simulation Of Timed Petri Nets, Javaid Aslam Siddiqi

Theses

A highly interactive graphical tool is developed for the drawing and simulation of discrete event systems involving time constraints. The Timed Petri Net Simulator tool (TPNS) is capable of simulating systems with deterministic and stochastic delays. Performance and utilization parameters are collected during simulation for behavior and analysis purposes. Simulation results are stored in different files (log, verify, utilize, and mark). Conflict resolution on the basis of priority or random selection of multiple transitions in conflict is implemented to handle complex modeling situations. A user friendly interface is developed for effective interaction between the tool and the user. This interface …

Factors Affecting Capacity Utilization In Industries: Hierarchical Analysis, M Victor

Tanzania Journal of Engineering and Technology (TJET)

This paper provides a hierarchical analysis of the factors affecting capacity utilization in Tanzanian industries. Several factors were identified and sent to randomly selected industries in Tanzania for ranking. The collected data was summarized and analyzed. The analysis made use of a known procedure, the 'Analytical Hierarchy Process' (AHP). The final results shows a ranking of the factors, on various hierarchical levels as to their percentage contribution in lowering the capacity utilization.

Fast Arithmetic Operations On The Hypercube Using Conditional Sum Addition And Modified Booth's Algorithm, Umar Bin Iftikhar

Theses

Algorithms for fast arithmetic operations (i.e., addition and multiplication) on the hypercube computer are presented. The hypercube network of dimension d interconnects N = 2^d processors in such a way that each processor is directly connected to d neighboring processors; m order to communicate between processors, the maximum length of the path is d. The addition algorithm is based on the conditional sum technique. The computational time using this algorithm is O(log₂ N+q) where q is the number of the bits per processor in the hypercube of N processors. Operands of size N*q are distributed among the hypercube …

Realization Of High-Speed Carry Propagation For Addition And Multiplication Using The Redundant Binary System On The Mesh And Hypercube Connected Structures, Anil Rana

Theses

The extensive development of large-scale digital computers has naturally been accompanied by a corresponding development of techniques for fast arithmetic operations. Addition is the basis for the majority of the other arithmetic operations and most of the required time is due to carry propagation delay. Various algorithms have been proposed for fast addition and multiplication. The algorithms proposed here use the redundant binary system and are designed for the mesh structure. The algorithms are very efficient for the addition and multiplication of long operands. The algorithms can also be implemented on the hypercube. The n-dimensional hypercube is a highly concurrent …

A Color Petri Net Simulation Tool, Sanjaykumar V. Desai

Theses

A user friendly, modular and highly interactive graphical tool for drawing, editing and simulating color Petri nets is developed. The tool is designed to model concurrent and interlocked systems, such as flexible manufacturing systems, communication protocols and computer systems. A Color Petri Net(CPN) has a more concise graphical system representation than a standard Petri net, because net entities in CPN carry information. The CPNS(Color Petri Net Simulation) tool simulates a net having conflicts, reveals deadlocks, and creates a log file with the state history of the system yielding performance measures.

Error Detection And Correction In Compressed Data, Nadir Sezgin

Theses

Encoded data is very sensitive to the channel errors. Especially if the data is compressed by Arithmetic Encoding procedure, then the error propagation is very high. The error propagation in Arithmetic Coding is studied. Exploiting the high error propagation property when compressing data by Arithmetic encoding procedure, two different algorithms have been proposed for error detection and correction. Under certain conditions these algorithms detect and with a very high probability correct the errors introduced to the compressed data.

Software Development For Analysis Of Stochastic Petri Nets Using Transfer Functions, Aman U. Jamwal

Theses

This thesis research is an implementation of a closed-form analytical technique for study, evaluation and analysis of Stochastic Petri Nets (SPN). The technique is based on a theorem that an isomorphism exists between an SPN and a Markov Chain. The procedure comprises five main steps: reachability graph generation of the underlying Petri net, transformation of the reachability graph to a state machine Petri net, calculation of transfer functions, computation of equivalent transfer functions via Mason's rule, and computation of performance parameters of the SPN model from the equivalent transfer functions and their derivatives. The software is developed in UNIX using …

Computer Aided Design Of A Broadband Microwave Power Divider, Jaideep Mukherjee

Theses

The purpose of this thesis to provide alternative design procedure for a power divider that has broadband characteristics. The Wilkinson power divider consisting of cascaded quarter wave sections is known to increase the bandwidth while maintaining high isolation and good match conditions at individual ports. Resistors placed between the quarter wave sections served to increase isolation. The values of required components were determined using odd and even mode analysis. In this work, the approximate theory developed previously is used as a preliminary design model, and it is extended further by considering optimization techniques and coupling between adjacent arms. This novel …

Extension And Applications Of Knitting Technique For Petri Net Synthesis, Yanzhong Zhang

Theses

Petri nets have been used for modeling and analyzing various systems [1,2,3,4,8]. One approach to Petri net synthesis is a knitting technique [4,5, 6,7]. It was developed for modeling concurrent systems. The Petri net model is incrementally expanded by adding paths of nodes according to rules. To extend the knitting technique to cover synchronized systems, a set of new rules based on synchronic distance concept is presented. The rules penult synchronizing M exclusive processes (M 2) to a synchronic distance of any positive integer N. They can be applied to both exclusive processes and independent processes. The resulting Petri net …

Ignoring Interprocessor Communication During Scheduling, Chintamani M. Patwardhan

Dissertations and Theses

The goal of parallel processing is to achieve high speed computing by partitioning a program into concurrent parts, assigning them in an efficient way to the available processors, scheduling the program and then executing the concurrent parts simultaneously. In the past researchers have combined the allocation of tasks in a program and scheduling of those tasks into one operation. We define scheduling as a process of efficiently assigning priorities to the already allocated tasks in a program. Assignment of priorities is important in cases when more than one task at a processor is ready for execution. Most heuristics for scheduling …

Spectral And Spatial Quantum Efficiency Of Algaas/Gaas And Ingaas/Inp Pin Photodiodes, Steven Alan Tabor

Dissertations and Theses

This thesis reports a novel system capable of testing both the spectral responsivity and the spatial quantum efficiency uniformity of heterostructure photodiodes using optical fiber coupled radiation. Testing was performed to confirm device specifications. This study undertakes to quantify the spectral bandwidth of an AlGaAs I GaAs double heterostructure photodiode and two InGaAs I InP double heterostructure PIN photodiodes at D.C., through the use of spatial scanning. The spatial scanning was done using lasers at 670 nm, 780 nm, 848 nm, 1300 nm, and 1550 nm, coupled through singlemode optical fiber. The AlGaAs I GaAs material system covers the 600 …

Simulation Of Finite-Precision Effects In Digital Filters, Perry L. Choate

Theses and Dissertations

This thesis develops and demonstrates software that models finite- precision effects in digital filters. Coefficient quantization and internally generated roundoff noise effects are simulated by rounding coefficients and multiplier output values to (B+1) bits. Outputs include magnitude and phase responses that may be plotted to show results of coefficient quantization. The output noise power due to roundoff is calculated. Three types of digital filter structures are examined. The first type is direct form I implementation for FIR and IIR structures, second is direct form II, and third is cascading the canonic direct form II second-order sections for higher order filter …

Function Prediction Using Recurrent Neural Networks, Randall L. Lindsey

Theses and Dissertations

A fully recurrent neural network was applied to the function prediction problem. The real-time recurrent learning (RTRL) algorithm was modified and tested for use as a viable function predictor. The modification gave the algorithm a variable learning rate and a linear/sigmoidal output selection. Verifying the networks ability to temporally learn both the classic exclusive-OR (XOR) problem and the internal state problem, the network was then used to simulate the frequency response of a second order IIR lowpass Butterworth filter. The recurrent network was then applied to two problems: head position tracking, and voice date reconstruction. The accuracy at which the …

Proportional Plus Integral Control Of Aircraft For Automated Maneuvering Formation Flight, John L. Dargan

Theses and Dissertations

In this study an automated formation control system for a lead and wing aircraft flight is developed. The proposed formation control system is capable of controlling like or dissimilar aircraft in maneuvering formation flight. Thus, two versions of the C-130 aircraft, the C-130A and the C-130B, are modelled. The C-130B has superior performance characteristics to that of the C- 130A. The wing aircraft continuously measures lead aircraft position with an ideal on-board relative position sensor, maneuvering to maintain relative position. External formation guidance is assumed to be released in a single data burst, consisting of formation geometry and nominal separation …

A Time-Dependent Adaptive Filter For Cochannel Interference Reduction, Matthew H. Foster

Theses and Dissertations

This thesis presents a Time Dependent Adaptive Filter (TDAF) which exploits the cyclostationarity of digitally modulated communications signals and seeks to improve the Signal to Interference Ratio (SIR) and Signal to Noise Ratio (SNR) of such signals. The TDAF is embedded in a computer simulation of a simple communication system consisting of a data source, data formatter, pulse shaping filter, BPSK modulator, and demodulator. In the simulation the TDAF and a Time Independent Adaptive Filter (TIAF) attempt to extract the Signal of Interest (SOI) from noise or interference. the criteria of Mean Squared Error (MSE) is used as the primary …

Comparison Of Afitpac Versus Nos And A Packet Radio Network Design, Thomas A. Iannelli

Theses and Dissertations

This thesis encompasses two themes: (1) A comparison of the Network Operating System (NOS) software package, developed by Phil Karn and others, and AFITPAC, written by Marsh and Geier at the Air Force Institute of Technology. The comparison is based on the Air Force Logistics Command's requirements for the development of a Packet Radio Network program. The results of the comparison are a recommendation that use of the NOS package be pursued because it can meet all twelve of the requirements and compiles with five of the Military Standard Protocols. (2) The design of a personal computer Packet Radio Network …

An Investigation Of A Design For A Finite-Difference Time Domain (Fdtd) Hardware Accelerator, James R. Marek

Theses and Dissertations

This study investigated increasing the speed of Finite-Difference Time Domain (FDTD) cell calculations through a special purpose architecture using Very Large Scale Integration (VLSI). These FDTD cell equations model inhomogeneous, isotropic, lossy magnetic and dielectric materials. Special attention was given to simplicity and performance, using the fastest components generally available in AFIT VLSI programs, while attempting to minimize component count. A VHSIC Hardware Description Language simulation of the proposed chip established design feasibility and provided performance estimates: 350 ns to generate the first cell value, 200 ns thereafter (30 MFLOPS maximum double-precision). This study also implemented boundary conditions in hardware …

Sensing Refractive Turbulence Profiles Using Wave Front Slope Measurements From Two Reference Sources, Michael D. Rejack

Theses and Dissertations

This thesis examines a remote sensing technique for measuring the atmospheric structure constant as a function of altitude by performing spatial correlation or wavefront sensor measurements. Two point sources are used to irradiate two wavefront sensors in the aperture plane of an optical system. The geometric relationship between the sources and the sensors gives rise to crossed optical paths. At the point where the paths cross, the correlation value of the turbulence contributions will be at a peak. The correlation is shown to be mathematically related to the structure constant in terms of an integral of the structure constant multiplied …