Engineering Commons^™

Automatic Analysis Of Electronic Drawings Using Neural Network, Yi Shi

Dissertations

Neural network technique has been found to be a powerful tool in pattern recognition. It captures associations or discovers regularities with a set of patterns, where the types, number of variables or diversity of the data are very great, the relationships between variables are vaguely understood, or the relationships are difficult to describe adequately with conventional approaches.

In this dissertation, which is related to the research and the system design aiming at recognizing the digital gate symbols and characters in electronic drawings, we have proposed: (1) A modified Kohonen neural network with a shift-invariant capability in pattern recognition; (2) An …

Adaptive Bootstrap Signal Separators For Bpsk/Qam-Modulated Wireless Cdma Systems In A Multipath Environment, Nico J.M. Van Waes

Dissertations

CDMA is an attractive multiple-access scheme, because of its potential capacity increase and its anti-multipath fading capability. For satisfactory performance, however, the effect of the "near-far" problem has to be resolved. This problem can be combated by using power-control, which, however, results in an overall reduction in communication ranges, and thus in a loss of capacity. Among other methods for mitigating the near-far problem is the use of decorrelating receivers, both of fixed type, which directly utilizes the cross-correlation of the users codes, and of adaptive type, which uses recursive algorithms that leads to signal decorrelation. Not to lessen the …

Space-Time Reduced Rank Methods And Cfar Signal Detection Algorithms With Applications To Hprf Radar, Tareq F. Ayoub

Dissertations

In radar applications, the statistical properties (covariance matrix) of the interference are typically unknown a priori and are estimated from a dataset with limited sample support. Often, the limited sample support leads to numerically ill-conditioned radar detectors. Under such circumstances, classical interference cancellation methods such as sample matrix inversion (SMI) do not perform satisfactorily. In these cases, innovative reduced-rank space-time adaptive processing (STAP) techniques outperform full-rank techniques. The high pulse repetition frequency (HPRF) radar problem is analyzed and it is shown that it is in the class of adaptive radar with limited sample support. Reduced-rank methods are studied for the …

A Low-Cost High-Speed Twin-Prefetching Dsp-Based Shared-Memory System For Real-Time Image Processing Applications, Charalambos Stephanou Christou

Dissertations

This dissertation introduces, investigates, and evaluates a low-cost high-speed twin-prefetching DSP-based bus-interconnected shared-memory system for real-time image processing applications. The proposed architecture can effectively support 32 DSPs in contrast to a maximum of 4 DSPs supported by existing DSP-based bus- interconnected systems. This significant enhancement is achieved by introducing two small programmable fast memories (Twins) between the processor and the shared bus interconnect. While one memory is transferring data from/to the shared memory, the other is supplying the core processor with data. The elimination of the traditional direct linkage of the shared bus and processor data bus makes feasible the …

Performance Improvements In Wireless Cdma Communications Utilizing Adaptive Antenna Arrays, Weichen Ye

Dissertations

This dissertation studies applications of adaptive antenna arrays and space-time adaptive processing (STAP) in wireless code-division multiple-access (CDMA) communications. The work addresses three aspects of the CDMA communications problems: (I) near-far resistance, (2) reverse link, (3) forward link. In each case, adaptive arrays are applied and their performance is investigated.

The near-far effect is a well known problem which affects the reverse link of CDMA communication systems. The near-far resistance of STAP is analyzed for two processing methods: maximal ratio combining and optimum combining. It. is shown that while maximal ratio combining is not near-far resistant, optimum combining is near-far …

Microengineered Sensor Devices With Field Emission Electron Sources, Chao Sun

Dissertations

This dissertation describes the design, simulation, fabrication, and characterization of a microengineered pressure sensor device and a microengineered mass spectrometer device, both of which use field emission cathode tip arrays as electron sources. VLSI and MEMS process techniques are used to scale down the dimensions from existing vacuum pressure sensors and mass spectrometers.

The microengineered pressure sensor device is fabricated on a silicon substrate approximately 1cm by 1cm. It consists of an electron source in the form of cathode tip array structure, an electron accelerating space which includes a gas ionization volume, and an ion collection electrode. The electrons emitted …

Performance Analysis Of The Interference Adaptation Dynamic Channel Allocation Technique In Wireless Communication Networks, Ziqiang Xu

Dissertations

Dynamic channel allocation (DCA) problem is one of the major research topics in the wireless networking area. The purpose of this technique is to relieve the contradiction between the increasing traffic load in wireless networks and the limited bandwidth resource across the air interface. The challenge of this problem comes from the following facts: a) even the basic DCA problem is shown to be NP-complete (none polynomial complete); b) the size of the state space of the problem is very large; and c) any practical DCA algorithm should run in real-time.

Many heuristic DCA schemes have been proposed in the …

Orthogonal Transmultiplexers : Extensions To Digital Subscriber Line (Dsl) Communications, Xueming Lin

Dissertations

An orthogonal transmultiplexer which unifies multirate filter bank theory and communications theory is investigated in this dissertation. Various extensions of the orthogonal transmultiplexer techniques have been made for digital subscriber line communication applications.

It is shown that the theoretical performance bounds of single carrier modulation based transceivers and multicarrier modulation based transceivers are the same under the same operational conditions. Single carrier based transceiver systems such as Quadrature Amplitude Modulation (QAM) and Carrierless Amplitude and Phase (CAP) modulation scheme, multicarrier based transceiver systems such as Orthogonal Frequency Division Multiplexing (OFDM) or Discrete Multi Tone (DMT) and Discrete Subband (Wavelet) Multicarrier …

Enhanced Terahertz Pulse Generation And Detection Using Electric Field Singularities In Photo-Conducting Antennas, Yi Cai

Dissertations

In recent years, generation of ultra-short electromagnetic pulses with frequency components in the terahertz (THz) range has been achieved by various techniques. Among those different methods, photo-conducting antennas have proven to be the most efficient source of THz radiation. THz spectrometers utilizing such photo-conducting antennas as transmitters and receivers are meanwhile routinely used for spectroscopic studies in the frequency regime between 0.1 to 5THz, which can be covered by neither conventional optical nor microwave spectrometers. However, THz emission power from the existing photo-conducting antenna is not sufficient for many applications (such as electro-optic sampling for real time THz detection and …

Design And Characterization Of Ultra High Frame Rate Burst Image Sensors, Rakesh K. Kabra

Dissertations

This thesis research was aimed at investigating and designing novel architectures required for ultra high frame rate (UHFR) imagers capable of operating at frame rates in excess of 10⁶ frames/sec. To demonstrate the feasibility of these architectures, a 180 x 180 element UHFR-I imager was designed and fabricated. The imager chip stored the latest 32 frames at its on-chip memory locations rather than performing a continuous readout. It was demonstrated that this architecture approach could achieve a frame acquisition rate of 2 x 10⁶ frames/sec. Additionally, other novel design features were incorporated to minimize optical cross talk and …

Dual Material Gate Field Effect Transistor (Dmg-Fet), Wei Long

Dissertations

Improving performance and suppressing short channel effects are two of the most important issues in present field effect transistors development. Hence, high performance and long channel like behaviors are essential requirements for short channel FETs. This dissertation focuses on new ways to achieve these significant goals. A new field effect transistor - dual material gate FET (DMG-FET) - is presented for the first time. The unique feature of the DMG-FET is its gate which consists of two laterally contacting gate materials with different work functions. This novel gate structure takes advantage of material work function difference in such a way …

Decentralized Reliable Control For Large-Scale Lti Systems, Zhengfang Chen

Dissertations

Reliable control concerns the ability of closed loop system to maintain stability and regulation properties during arbitrary sensor, controller, and actuator failure. Reliable control research has been an active research topic for more than 10 years.

Recent approach for reliable control includes the H∞ method, the algebraic factorization design, and the robust servomechanism control. These methods have been surveyed and discussed in this thesis with the robust servomechanism control methodology serving as the basis of the research development of this work.

In this thesis, the reliable control for large-scale, multi-input/output linear system is considered. Two concepts of reliable control …

Cantilever Beam Microactuators With Electrothermal And Electrostatic Drive, Murat M. Okyar

Dissertations

Microfabrication provides a powerful tool for batch processing and miniaturization of mechanical systems into dimensional domain not accessible easily by conventional machining. CMOS IC process compatible design is definitely a big plus because of tremendous know-how in IC technologies, commercially available standard IC processes for a reasonable price, and future integration of microma-chined mechanical systems and integrated circuits. Magnetically, electrostatically and thermally driven microactuators have been reported previously. These actuators have applications in many fields from optics to robotics and biomedical engineering.

At NJIT cleanroom, mono or multimorph microactuators have been fabricated using CMOS compatible process. In design and fabrication …

Micro Electromechanical Relays And Their Application In Variable Inductor Networks, Shifang Zhou

Dissertations

A family of microrelay devices together with integrated inductor networks has been designed, simulated, fabricated and experimental characterized. These switched networks utilize microelectromechanical systems (MEMS) as a fabrication technology and take advantage of the economies of semiconductor cleanroom batch-processing.

A new type of microrelay has been developed using a suspended TaSi₂/SiO₂ bimorph cantilever beam, gold-to-gold electrical contact, aluminum as sacrificial layer, and a combined thermal and electrostatic means of actuation. For the first time a micro variable inductor network which is digitally controlled by microrelays has been demonstrated. A test structure for electrical micro contact characterization has …