Digital Commons Network^™

Measurement Techniques For Noise Figure And Gain Of Bipolar Transistors, Wayne Kan Jung

Dissertations and Theses

First, the concepts of reflection coefficients, s-parameters, Smith chart, noise figure, and available power gain will be introduced. This lays out the foundation for the presentation of techniques on measuring noise figure and gain of high speed bipolar junction transistors. Noise sources in a bipolar junction transistor and an equivalent circuit including these noise sources will be presented. The process of determining the noise parameters of a transistor will also be discussed. A Pascal program and several TEKSPICE scripts are developed to calculate the stability, available power gain, and noise figure circles. Finally, these circles are plotted on a Smith …

Existence Of High-Order Superlattices In Orientationally Ordered C_{60}, J. E. Fischer, D. E. Luzzi, K. Kniaź, A. R. Mcghie, D. A. Ricketts-Foot, W. R. Romanow, Gavin B. M. Vaughan, Dayin Li, Allan L. Smith, Robert M. Strongin, M. A. Cichy, Laurent Bard, Amos B. Smith Iii

Chemistry Faculty Publications and Presentations

We correlate the presence or absence of high-order modulated structures in solid C₆₀ with the differential scanning calorimetry signature of the orientational ordering transition and other diagnostic data. We have searched for, but not observed, the 2a face-centered cubic structure recently observed in low-temperature electron and single-crystal x-ray diffraction. We conclude that the intrinsic ground state is the previously reported simple cubic structure [space groupPa3¯, a(14 K)=14.06 Å], and that other structures may be stabilized by defects or impurities.

Coherence Peak And Superconducting Energy Gap In Rb_{3}C_{60} Observed By Muon Spin Relaxation, R. F. Kiefl, W. A. Macfarlane, K. H. Chow, S. Dunsiger, T. L. Duty, T. M. S. Johnston, J. W. Schneider, J. Sonier, Laurent Brard, Robert M. Strongin, J. E. Fischer, Amos B. Smith Iii

Chemistry Faculty Publications and Presentations

Muon spin relaxation resulting from spin exchange scattering of endohedral muonium (μ+e-) with thermal electronic excitations has been observed in the fullerene superconductor Rb₃C₆₀. The temperature dependence of T₁^-1 shows a coherence peak just below T_c and can be fit to the conventional Hebel-Slichter theory for spin relaxation in a superconductor with a broadened BCS density of states. The average energy gap for electronic excitations, Δ/k_B=53(4) K or 2Δ/ k_BT_c=3.6(3), is consistent with the BCS weak coupling limit.

Gravity Sedimentation: A One-Dimensional Numerical Model, Joanna Robin Karl

Dissertations and Theses

A large fraction of the current cost of wastewater treatment is from the treatment and disposal of wastewater sludge. Improved design, energy efficiency, and performance of dewatering facilities could significantly decrease transport and disposal costs.

Dewatering facilities are designed based on field experience, trial and error, pilot plant testing, and/or full scale testing. Design is generally time-consuming and expensive. A full-scale test typically consists of side-by-side operation of 4 to 5 full-scale dewatering units for several weeks to more than 6 months. Theoretical modeling of the physics of dewatering units such as the belt filter press, based on laboratory determined …

Designing And Simulating A Multistage Sampling Rate Conversion System Using A Set Of Pc Programs, David Joseph Hagerty

Dissertations and Theses

The thesis covers a series of PC programs that we have written that will enable users to easily design FIR linear phase lowpass digital filters and multistage sampling rate conversion systems. The first program is a rewrite of the McClellan-Parks computer program with some slight modifications. The second program uses an algorithm proposed by Rabiner that determines the length of a lowpass digital filter. Rabiner used a formula proposed by Herrmann et al. to initially estimate the filter length in his algorithm. The formula, however, assumes unity gain. We present a modification to the formula so that the gain of …

Designing And Simulating A Multistage Sampling Rate Conversion System Using A Set Of Pc Programs, David Joesph Hagerty

Dissertations and Theses

The thesis covers a series of PC programs that we have written that will enable users to easily design FIR linear phase lowpass digital filters and multistage sampling rate conversion systems. The first program is a rewrite of the McClellanParks computer program with some slight modifications. The second program uses an algorithm proposed by Rabiner that determines the length of a lowpass digital filter. Rabiner used a formula proposed by Herrmann et al. to initially estimate the filter length in his algorithm. The formula, however, assumes unity gain. We present a modification to the formula so that the gain of …

Quasi-Static Deflection Compensation Control Of Flexible Manipulator, Jingbin Feng

Dissertations and Theses

The growing need in industrial applications of high-performance robots has led to designs of lightweight robot arms. However the light-weight robot arm introduces accuracy and vibration problems. The classical robot design and control method based on the rigid body assumption is no longer satisfactory for the light-weight manipulators. The effects of flexibility of light-weight manipulators have been an active research area in recent years. A new approach to correct the quasi-static position and orientation error of the end-effector of a manipulator with flexible links is studied in this project. In this approach, strain gages are used to monitor the elastic …

Distributed Economic Systems With Agents That Learn, Stanley Foster Perry

Dissertations and Theses

Economic systems are distributed in the sense that economic agents make decisions without any central control. Prices, quantities, wealth, and market structure emerge from the interaction of agents acting in their own self interest. The concepts and language of systems science are used to define economic systems in a manner that captures and articulates the distributed nature of economic systems. Further, the systems definition permits multiple views of the economic system, and in addition, allows the agents to "step outside" the system in order to study it.

Economic systems are defined in such a way that it is feasible to …

Faculty Senate Monthly Packet May 1993, Portland State University Faculty Senate

Faculty Senate Monthly Packets

The May 1993 Monthly packet includes the May agenda and appendices and the Faculty Senate minutes and attachments from the meeting held April 1993.

Spontaneous Coherent Pulsations In Standing-Wave Laser Oscillators: Stability Criteria For Homogeneous Broadening, Pitak Chenkosol, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

The stability criteria for single-mode standing-wave laser oscillators in the homogeneously broadened limit are reported, and two types of criteria are distinguished. The first type (type 1) corresponds to the minimum value of the threshold parameter for which an infinitesimal perturbation away from steady state grows into an oscillatory solution. A second type (type 2) corresponds to the minimum value of threshold parameter for which large-amplitude oscillations do not decay to the steady-state solution. Undamped pulsations in single-mode homogeneously broadened standing-wave laser oscillators are found to occur at a much higher excitation level than in ring-laser oscillators with homogeneous broadening. …

Unusual Thermal Stability Of A Site-Ordered Mc60 Rocksalt Structure (M=K, Rb, Or Cs), Q. Zhu, O. Zhou, J. E. Fischer, Andrew R. Mcghie, W. R. Romanow, Robert M. Strongin, M. A. Cichy, Amos B. Smith Iii

Chemistry Faculty Publications and Presentations

X-ray diffraction and differential scanning calorimetry of M_xC₆₀, with x∼1 and M=K, Rb, or Cs, reveal an unusual T-dependent phase sequence. A low-symmetry ground state is found, while the high-T limit is an ordered rocksalt structure in which only the octahedral sites are occupied. The unusual high-T stability of this ordered phase is attributed to the entropy of molecular orientational disorder and/or thermal disorder of the alkali-metal ions within the octahedral sites. Unique to K_xC₆₀ with x≥1.4, we find at intermediate temperatures an fcc site-disordered lattice gas …

Portland State Magazine, Portland State University. Office Of University Communications

Portland State Magazine

PSU’s alumni magazine, published 2-3 times a year. In this issue: Four former PSU students are winners of the Milken Family Foundation’s 1992 National Educator Award; state legislators dealing with the fallout of Measure 5 tell higher education it must be 15 percent more productive; Richard Toscan, dean of the school of fine and performing arts, seeks to forge more ties with the local arts community; Jack Ohman, editorial cartoonist for The Oregonian, writes about his decision to enroll at PSU; Professor Devorah Leiberman says misunderstandings caused by cultural differences can be avoided; Professor Marek Perkowski’s research may someday result …

A Robust High Precision Algorithm For Sinewave Parameter Estimation, Kendall Ann Rydell

Dissertations and Theses

The estimation of sinewave parameters has many practical applications in test and data processing systems. Measuring the effective bits of an analog-to-digital converter and linear circuit identification are some typical examples. If a sinew ave's frequency is known, there is an established linear method to estimate the other parameters. But when none of the parameters are known (which is usually the case in practical situations), the estimation problem becomes more difficult. Traditional approaches to this task applied an iterative, sinewave curve-fit algorithm. Two problems with this technique are that convergence is often slow and not always guaranteed and the results …

The Effects Of Airline Deregulation On Airline Safety: An Econometric Analysis, William Charles De Jager

Dissertations and Theses

After an unfortunate series of accidents in the mid 1930's the Air Transport Association (ATA) lobbied Congress for regulation of the industry. The ATA claimed that unfair competition was endangering the public safety. The Civil Aeronautics Act of 1938 created the Civil Aeronautics Board (CAB) and gave the CAB the authority to regulate the industry.

During the regulation era airline ridership increased and safety improved. During the regulation period, opportunity for comparing the safety record of the regulated industry with the record of the unregulated portions of the industry was limited. The few attempts made rendered inconclusive results.

During a …

One-Dimensional Computer Modeling Of Thermal And Water Quality Characteristics Of Coldwater Lake, Wa, David Kevin Whitaker

Dissertations and Theses

Coldwater Lake is a new lake formed when a massive mudflow down the Toutle River Valley, caused by the eruption of Mount St. Helens on May 18, 1980, blocked the natural outlet of Coldwater Creek. This research utilizes physical, biological and chemical data collected at Coldwater Lake during the sun1mers of 1989 and 1990 to calibrate and verify the one-dimensional computer models CE-THERMRl and CE-QUAL-Rl for Coldwater Lake. CE-THERM-R1 was used to simulate thermal characteristics in Coldwater Lake during the summer stratification periods of 1989 and 1990. The model was calibrated to 1989 data and was verified with 1990 data. …

Meeting Notes 1993-04-08 , Joint Policy Advisory Committee On Transportation

Joint Policy Advisory Committee on Transportation

No abstract provided.

Central America: An Attempt At Modern Economic Growth, Richard Kibbey

Dissertations and Theses

Since World War II the five historic Central American nations, Costa Rica, EI Salvador, Guatemala, Honduras and Nicaragua, underwent a period of aggregate economic growth which was followed by a collapse of dramatic proportions. All five countries experienced an economic downturn in the latter 1970s which led to several years of declining GDP and GDP per capita, together with an economic and social disarray which is typically referred to as "la crisis" in Central American literature.

The intent of this study is to present an argument for the position that the economic collapse of the five Central American nations was …

Temperature Dependence Of Optical Properties For Amorphous Silicon At Wavelengths Of 632.8 And 752 Nm, P.T. Leung, Nhan Do, Oguz Yavas, Andrew C. Tam, Wing P. Leung, Hee K. Park, Costas P. Grigoropoulos, Johannes Boneberg, Paul Leiderer

Physics Faculty Publications and Presentations

The temperature dependence of the optical properties for amorphous silicon is studied at wavelengths of 632.8 and 752 nm. Both the refractive index and extinction coefficient increase linearly with temperature for 752 nm, while the refractive index decreases and the extinction coefficient increases for 632.8 nm. The rate of increase of the extinction coefficient at 632.8 nm is twice as much as that for 752 nm.

City Club Of Portland Report On Downtown Parking, City Club Of Portland (Portland, Or.)

City Club of Portland

No abstract provided.

Lents: Alternatives For The Future, Kent Healy, Shea Gumusoglu, Mark Dane, Steve Kelley, Jim Holycross, Ning-Sheng Zhou, Michael Ray, Sean Loughran, Kyle Bairnsfather, Peggy Scolnick, Matt Zybas

Master of Urban and Regional Planning Workshop Projects

This document is the complement to the Issues Analysis. The Issues Analysis looked at the problems and issues which confront the Lents neighborhood. This document proposes actions that can be taken to address the issues identified in the previous analysis. Each section, e.g. Environment, Transportation, etc., has its own goals and subsequent objectives and actions. A goal is a broad statement of what is the desired outcome for the neighborhood. More specific objectives identify what needs to be done to improve things and to remedy the identified problems. The actions are means to achieve an objective. Specific potential implementers are …

Meeting Notes 1993-03-11 , Joint Policy Advisory Committee On Transportation

Joint Policy Advisory Committee on Transportation

No abstract provided.

Comprehension Of Literate Programs By Novice And Intermediate Programmers, Christopher Forrest Bertholf

Dissertations and Theses

The studies reported herein compare comprehension of Lit style literate programs to that of traditional modular programs documented by embedded comments. Novice and intermediate programmers participated in three experiments designed to determine the comprehensibility of literate programs written using a language-independent system for abstraction-oriented literate programming compared with programs written using traditional modular programming techniques (traditional modular programs). Programs were written in either the C or FORTRAN programming language. Half of the subjects in each group received a literate program, while the other half received a traditional modular program with embedded documentation. Subjects received a problem specification, input and output …

Smart Memory: An Inexact Content-Addressable Memory, Jack Lee

Dissertations and Theses

The function of a Content-Addressable Memory (CAM) is to efficiently search the information stored in the memory, by using hardware rather than software with a corresponding improvement in searching speed. This hardware allows a parallel search by matching the data stored in memory to a search key rather than sequentially searching address by address as is done in a Random Access Memory. Although existing CAMs are more efficient in finding relevant information than RAM, there are additional improvements that can be made to further improve its efficiency. For example, previous CAMs use a word parallel searching scheme that can only …

Exact Modeling Of Time-Interval-Modulated Switched Networks, Weihe Niu

Dissertations and Theses

The frequency response analysis of switched networks plays a very important part in designing various kinds of power converter circuits. In this thesis two frequency response techniques for analyzing switching power converters are discussed. One method provides a mathematical description which treats the converter as a periodic time varying system. A linearized small signal model is subsequently derived. The major part of the thesis concentrates on this accurate exact small-signal technique. The derivation involves state space representation and the use of the time varying transfer function. A Fourier analysis is performed to show the relationship between the frequency response of …

Matching Points To Lines: Sonar-Based Localization For The Psubot, Kevin Blythe Stanton

Dissertations and Theses

The PSUBOT (pronounced pea-es-you-bought) is an autonomous wheelchair robot for persons with certain disabilities. Its use of voice recognition and autonomous navigation enable it to carry out high level commands with little or no user assistance. We first describe the goals, constraints, and capabilities of the overall system including path planning and obstacle avoidance. We then focus on localization-the ability of the robot to locate itself in space. Odometry, a compass, and an algorithm which matches points to lines are each employed to accomplish this task. The matching algorithm (which matches "points" to "lines") is the main contribution to this …

Meeting Notes 1993-02-11 , Joint Policy Advisory Committee On Transportation

Joint Policy Advisory Committee on Transportation

No abstract provided.

Novel Cylindrical Illuminator Tip For Ultraviolet Light Delivery, Hanqun Shangguan

Dissertations and Theses

The design, processing, and sequential testing of a novel cylindrical diffusing optical fiber tip for ultraviolet light delivery is described. This device has been shown to uniformly(+/- 15%) illuminate angioplasty balloons, 20 mm in length, that are used in an experimental photochemotherapeutic treatment of swine intimal hyperplasia. Our experiments show that uniform diffusing tips of < 400 micron diameter can be reliably constructed for this and other interstitial applications. Modeling results indicate that this design is scalable to smaller diameters. The diffusing tips are made by stripping the protective buffer and etching away the cladding over a length of 20 mm from the fiber tip and replacing it with a thin layer of optical epoxy mixed with A/203 powder. To improve the uniformity and ease of fabrication, we have evaluated a new device configuration where the tip is etched into a modified conical shape, and the distal end face is polished and then coated with an optically opaque epoxy. This is shown to uniformly scatter - 70% of the light launched into the fiber without forward transmission. To our knowledge, we are the first to use this device configuration, and we have achieved a uniform cylindrical pattern of laser energy with uniformity < ± 15% of the average value. A simple computational model suitable for the interpretation of laser energy irradiance along the bare core surface of multimode optical fiber tips is proposed and experimentally verified. The model used is based on geometrical optics and Gaussian approximation. Good agreement is obtained between the calculation and experiment. We have measured the optical properties of the tips through all the sequences of the fabrication. The performances of the diffusing tips for illuminating angioplasty balloons are then evaluated by Ultraviolet Light at 365 nm. A Ti:Sapphire Ring Laser System with a doubling crystal pumped by an argon ion laser is used to generate the wavelength in this study.

Minimization Of Permuted Reed-Muller Trees And Reed-Muller Trees For Cellular Logic Programmable Gate Arrays, Lifei Wu

Dissertations and Theses

The new family of Field Programmable Gate Arrays, CLI 6000 from Concurrent Logic Inc realizes truly Cellular Logic. It has been mainly designed for the realization of data path architectures. However, the realizable logic functions provided by its macrocells and their limited connectivity call also for new general-purpose logic synthesis methods. The basic cell of CLi 6000 can be programmed to realize a two-input multiplexer ( A*B + C*B ), an AND/EXOR cell ( A*B Ea C ), or the basic 2-input AND, OR and EXOR gate. This suggests to using these cells for tree-like expansions. These "cellular logic" devices …

Dynamics Of Ultrashort Pulse Generation And Amplification In Dye Lasers, Shuanghua Jiang

Dissertations and Theses

The dynamics of ultrashort pulse generation and amplification in dye lasers is studied in this dissertation. In particular, we have developed general semiclassical models for ultrashort pulse dye laser amplifiers and oscillators. These models start from Maxwell's equation for the electric field and density matrix equations for the active laser medium. A finite coherence time or phase memory time of the molecular wave functions, a finite vibrational relaxation time for the lower electronic state of the dye laser transition, an isotropic molecular orientational distribution, and an arbitrary pump polarization are all taken into account. Based on these models, specific topics …

The Design Of High-Frequency Continuous-Time Integrated Analog Signal Processing Circuits, Pan Wu

Dissertations and Theses

High-performance, high-frequency operational transconductance amplifiers (OTAs) are very important elements in the design of high-frequency continuous-time integrated analog signal processing circuits, because resistors, inductors, integrators, mutators, buffers, multipliers, and filters can be built by OTAs and capacitors. The critical considerations for OTA design are linearity, tuning, frequency response, output impedance, power supply rejection (PSR) and common-mode rejection (CMR). For linearity considerations, two different methods are proposed. One uses cross-coupled pairs (CMOS or NMOS), producing OTAs with very high linearity but either the input range is relatively small or the CMR to asymmetrical inputs is poor. Another employs multiple differential pairs …