Engineering Commons^™

Microstrip Zero-Sum Antenna; Cad And Experimental Study, Tuan H. Lam

Theses

A microstrip antenna array consisting of two elements combined with a stripline hybrid (rat-race) ring coupler is used to implement a zero-sum antenna. Numerical optimization of individual antenna elements in terms of feed location and patch size was achieved using IE3D (Zeland Software Inc., Fremont, CA), a fullwave 3-D planar electromagnetic simulation software. Further, design of a hybrid (rat-race) ring coupler in a stripline environment was carried out, yielding the sum and difference functions as 0.5 dB and 40 dB, respectively. A combination of a two-element antenna array and a hybrid (rat-race) ring coupler as a zero sum antenna has …

Analysis Of 320x240 Uncooled Microbolometer Focal Plane Array And Design Of Thermoelectric Cooler Controller, Takayoshi Fukaya

Theses

Uncooled microbolometer focal plane array is one of the promising method used in uncooled infrared imaging projects. The array's advantages over the conventional cooled imagers are its ability to operate without cryogenic cooler or dewar and its low cost. For the past several years, the ULTRA (Uncooled, Low cost, Technology Reinvestment Alliance) Consortium has been developing uncooled microbolometer imaging system.

This thesis investigates the technology behind the ULTRA camera system. The theoretical as well as the operation of the uncooled microbolometer focal plane array and the processing hardware and software is analyzed and explained.

Thermoelectric cooler controller for the microbolometer …

Petri Net Modeling And Performance Analysis Of Z39.50 Search And Retrieval Protocol, Roopali Paranjpe

Theses

Z39.50 is an American Standard for information retrieval. The standard depicts a client-server model of computing. With reference to the Open System Interconnection (COSI)) model developed by International Standards Organization (ISO); Z39.50 is an application layer protocol. A Z39.50 client performs searching, querying and requesting functions and a Z39.50 server interfaces with the database in the remote system and responds to client requests by providing a set of records for the search query.

Z39.50 state tables describe a complex set of concurrent and serial events. A Petri net model is prepared for the entire system comprising the protocol. A Petri …

Low Frequency Characterization Of A Loop Antenna, Irene Koukhta

Theses

The conventional solution of an integral equation for the loop antenna in free space can be expressed analytically using Fourier Series. However, the solutions based on delta gap feed model yield divergent input susceptance.

To overcome such diverging results, alternative solution using equivalent magnetic frill current feed models were implemented. Although low frequency models for delta gap feeds were suggested, no generalized low frequency expansions for the input admittance have been reported previously. In this work, such generalized low frequency expansion are developed for both delta-gap and magnetic frill feeds of loop antennas. Validity of such expansion have been investigated …

Analysis And Comparison Of Resistive, Ferroelectric And Pyroelectric Uncooled Bolometers For Electronic Imaging Systems, Mo-Huang Li

Theses

The performance parameters (responsivity (R_v). detectivity (D*), total noise and response time) of resistive, pyroelectric and ferroelectric bolometer detectors are dependent on a large number of key variables including chopping frequercy, the input impedance and voltage noise of the readout circuitry, the structure dependent parameters (particularly thermal conductance and thermal capacitance), and material properties such as dielectric constant, pyroelectric coefficient, loss tangent and thin film thickness. The interrelationship between the key variables and their influence on performance is often complex and not easily discerned for the three major types of thermal detectors: resistive, pyroelectric and ferroelectric bolometers.

In …

Vibration Control Of Robotic Modules Using Input Shaping Algorithm, Murat Eren

Theses

In this thesis, vibration control using input shaping algorithm is studied. Vibration Control of flexible structures is an important problem and has been an active research area. Different approaches have been developed for vibration control which can be divided roughly into feedback and feedforward methods. Feedback methods need measurements and on-line calculation of the controller outputs. Although feedback methods are generally more robust and have a number of well known performance advantages, proper use of feedforward control can also significantly improve the speed of response of the system.

Input shaping is one of these feedforward methods. It has been successfully …

Performance Evaluation Of Cebus Power Line Communication In The Presence Of X-10 Module Signaling, Nashwa F. Kamel

Theses

A power line of CEBus has great potential towards inexpensive home automation. Both PLBus and X-10 uses [sic] burst of 120KHz signals to transmit bits of information on the power line. However, these two systems are completely incompatible and can conflict with each other. This thesis presents the first performance evaluation of Power Line CEBus communication in the presence of X-10 module signaling. The evaluation included simulation experiments measuring packet delays, message delays, message throughput, channel throughput and the percentage of messages received in error verses [sic] different loads. Network performance has been confirmed to function well in terms of …

A Cost Model For Multi-Lifecycle Engineering Design, Bin Zhang

Theses

Design for Environment aims to yield a product whose aggregate environmental impact is as small as possible. This thesis characterizes a product recovery system and defines the concepts of product lifetime and part lifetime. A multi-lifecycle product recovery model is developed based on the concepts of product tree and disassembly path representation, four product recovery choices, time varying costs, cost comparison. The four product recovery choices of a part in the product tree are: Reconditioning, Part Remanufacturing, Material Recycling, and Landfill. This thesis focuses on how to improve the product design while minimizing environmental impact of the product and introduces …

Tcp/Ip Traffic Over Atm Network With Abr Flow And Congestion Control, Liping An

Theses

Most traffics over the existing ATM network are generated by applications running over TCP/IP protocol stack. In the near future, the success of ATM technology will depend largely on how well it supports the huge legacy of existing TCP/IP applications.

In this thesis, we study and compare the performance of TCP/IP traffic running on different rate based ABR flow control algorithms such as EFCI, ERICA and FMMRA by extensive simulations. Infinite source-end traffic behavior is chosen to represent, FTP application running on TCP/IP. Background VBR traffic with different ON-OFF frequency is introduced to produce transient network states as well as …

The Electrodynamic Levitation Of A Collar : Analysis, Experimentation And Simulation, Philip Nixon

Theses

This dissertation describes various methods of maintaining a collar levitated in a vertical axis, using the well-known principle of electromagnetic induction between two circuits. The advantages of closing the magnetic loop around the collar, to obtain large radial flux cutting the collar and, therefore, large lifting forces for a given induced current, are considered in depth.

The ideal magnetic circuit and the equivalent electrical circuit are used in developing a model for two topologies of core (both an open and closed-circuit core) levitating a nonmagnetic conducting collar above a coil. Various affects that degrade the performance of the levitation rig …

An Analysis Of Printed Circuit Boards During Reflow Soldering., Paul Barry

Theses

Electronic manufacturing is currently one of the fastest growing industrial areas. This is due to the rapid advances in the computer and telecommunications sectors. Due to these advances, new surface mount devices have been developed to achieve greater miniaturisation at lower costs. As a result, a new surface mount technology has been developed to mount these devices onto printed circuit boards. However, problems exist with aspects of this process, principally open solder joints which result from circuit board warpage. The aim of this thesis is to undertake a) both an experimental and theoretical investigation of the reflow solder process and …