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Articles 21991 - 22020 of 33701

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A New Approach To Automatic Target Recognition Using Wavelet Transforms, Anitha Panapakkam, S. N. Balakrishnan, Daniel St. Clair Dec 1994

A New Approach To Automatic Target Recognition Using Wavelet Transforms, Anitha Panapakkam, S. N. Balakrishnan, Daniel St. Clair

Computer Science Technical Reports

Automatic Target Recognition (ATR) systems have significant impact in defense applications. There is a continuing need to develop new and robust techniques to handle the increasingly complex ATR problem. The objectives of this thesis are two-fold. First a new technique to be used for ATR is developed and secondly an integrated ATR system to investigate and combine all subsystems is developed. In this thesis, we have developed a new technique for the feature extraction stage of ATR problem using wavelet transforms. Wavelet transforms have been one of the widely investigated areas of research in the past few years. The promising …

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Foam Flotation Enrichment Of Enantiomers, Daniel W. Armstrong, Eve Y. Zhou, Shushi Chen, Kang Le, Yubing Tang Dec 1994

Foam Flotation Enrichment Of Enantiomers, Daniel W. Armstrong, Eve Y. Zhou, Shushi Chen, Kang Le, Yubing Tang

Chemistry Faculty Research & Creative Works

Adsorptive bubble separation methods are known to be useful for processing large amounts of material at a relatively low cost These techniques have been used to enrich components from both heterogeneous and homogeneous solutions. There is a need for economical process-scale enantiomeric separations. Thus far there has been little evidence to support the feasibility of using an adsorptive bubble process to enrich enantiomers. We demonstrate that foam-forming chiral collectors can be used in conjunction with an inexpensive glass device to enantiomerically enrich some pharmaceutically important compounds as well as derivatized and underivatized amino acids. Factors that appeared to affect this …

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Performance Monitoring Of Hybrid Intelligent Systems, Nariman Abdel Baky, Fikret Ercal Dec 1994

Performance Monitoring Of Hybrid Intelligent Systems, Nariman Abdel Baky, Fikret Ercal

Computer Science Technical Reports

Development of an automated system to enable the ongoing monitoring and control of the performance of HIS is a step towards increasing the confidence and security with which ordinary users will perceive AI-based Systems. The main objective of this research was to develop a prototype intelligent system to perform this monitoring. The proposed monitming system integrates performance metrics for the HIS's components with heuristics for evaluating data quality by checking data types, data ranges, percentage of missing data and the composition of data. The research demonstrated the possibility of developing such system and the feasibility of using it for a …

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Ccsp - A Formal System For Distributed Program Debugging, Hanan Lutfiyya, Bruce Mcmillin, Beth Arrowsmith, Cristina Serban Dec 1994

Ccsp - A Formal System For Distributed Program Debugging, Hanan Lutfiyya, Bruce Mcmillin, Beth Arrowsmith, Cristina Serban

Computer Science Technical Reports

One major problem with programming in a parallel/distributed environment is the difficulty in debugging the programs owing to the complex interactions of their component processes. Complete knowledge of the program's state is not generally attainable in a distributed system. This paper presents a distributed system for debugging distributed programs that allows for the execution and evaluation of embedded assertions expressed in Hoare's CSP [6]. We show examples of the use of this system, prove its correctness, and describe how the system can be used for the more general case of ensuring an application's correctness at run-time.

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Energy Spread And Ion Current Measurements Of Several Ion Sources, A. D. Gaus, W. T. Htwe, J. A. Brand, Timothy James Gay, Michael Schulz Dec 1994

Energy Spread And Ion Current Measurements Of Several Ion Sources, A. D. Gaus, W. T. Htwe, J. A. Brand, Timothy James Gay, Michael Schulz

Physics Faculty Research & Creative Works

Energy spread and extracted current measurements are presented for five different types of ion sources: hot cathode, cold cathode, magnetron, microwave, and electron cyclotron resonance (ECR). The measurements were performed with a 45° parallel-plate energy analyzer with a resolution of better than 0.5 eV at 500 eV incident energy. Energy spreads ranged from 0.5 to 4 eV, while total extracted beam currents ranged from 2 to 30 μA. Beam currents due specifically to protons, 3He++ ions, and H +2 ions are also presented. The ECR and magnetron sources gave the best overall performance. These, along with the energy analyzer, are …

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A Contactless Method For Measuring The Bulk Resistance Of Ii-Vi Compound Semiconductors, Edward D. Wheeler, Jack L. Boone, James L. Drewniak Dec 1994

A Contactless Method For Measuring The Bulk Resistance Of Ii-Vi Compound Semiconductors, Edward D. Wheeler, Jack L. Boone, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A radio frequency measurement technique for measuring the bulk resistivity of II-VI compound semiconductors is described. Wafers of n-type CdS are used to demonstrate the technique. An equivalent circuit model is introduced which predicts a frequency dependence for the CdS wafer impedance which agrees well with the experiment. The model assumes a broad distribution of relaxation times associated with the polarization. The radio frequency method gives values for the resistivity within 15% of four point probe measurements for the lower resistivity wafers, and within 5% for the higher resistivity wafers.

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Identification And Robust Control Of Smart Structures Using Artificial Neural Networks, R. Damle, R. Lashlee, Vittal S. Rao, Frank J. Kern Dec 1994

Identification And Robust Control Of Smart Structures Using Artificial Neural Networks, R. Damle, R. Lashlee, Vittal S. Rao, Frank J. Kern

Electrical and Computer Engineering Faculty Research & Creative Works

This paper describes an integrated approach to design and implement robust controllers for smart structures. To demonstrate this procedure, we have designed and fabricated a structural test article incorporating shape memory alloy (SMA) actuators, strain gauge sensors, signal-processing circuits and digital controllers with flexible structures. A neural-network-based structural identification method to determine a state space model of the system from its experimental input/output data is presented. To reduce the learning time required to train a neural network significantly, we have developed an accelerated adaptive learning-rate algorithm. The mathematical model derived using neural networks is compared with models obtained by more …

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The Missouri Miner, November 30, 1994 Nov 1994

The Missouri Miner, November 30, 1994

The Missouri Miner Newspaper

No abstract provided.

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The Missouri Miner, November 16, 1994 Nov 1994

The Missouri Miner, November 16, 1994

The Missouri Miner Newspaper

No abstract provided.

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The Missouri Miner, November 09, 1994 Nov 1994

The Missouri Miner, November 09, 1994

The Missouri Miner Newspaper

No abstract provided.

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The Missouri Miner, November 02, 1994 Nov 1994

The Missouri Miner, November 02, 1994

The Missouri Miner Newspaper

No abstract provided.

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A Magnetic, Neutron Diffraction, And Mössbauer Spectral Study Of The Nd₂Fe₁₇₋ₓalₓ Solid Solutions, Gary J. Long, Gaya Kanishka Marasinghe, Sanjay R. Mishra, Oran Allan Pringle, Zhongbo Hu, William B. Yelon, D. P. Middleton, K. H. J. Buschow, Fernande Grandjean Nov 1994

A Magnetic, Neutron Diffraction, And Mössbauer Spectral Study Of The Nd₂Fe₁₇₋ₓalₓ Solid Solutions, Gary J. Long, Gaya Kanishka Marasinghe, Sanjay R. Mishra, Oran Allan Pringle, Zhongbo Hu, William B. Yelon, D. P. Middleton, K. H. J. Buschow, Fernande Grandjean

Chemistry Faculty Research & Creative Works

The magnetic properties of a series of Nd2Fe17-xAlx solid solutions, with x equal to 2.04, 4.01, 5.97, 7.94, and 9.06, have been studied by magnetic measurements, neutron diffraction, and Mössbauer spectroscopy. Magnetization studies indicate that the Curie temperature increases from 330 K in Nd2Fe17 to a maximum of ~470 K at an x of 3.5. The compounds crystallize in the Th2Zn17 structure with lattice parameters and unit cell volumes which increase linearly with increasing aluminum content. The neutron diffraction results indicate that aluminum atoms are excluded from the 9d …

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R-By-C Crozzle: An Np-Hard Problem, Michelle Gower, Ralph Wilkerson Nov 1994

R-By-C Crozzle: An Np-Hard Problem, Michelle Gower, Ralph Wilkerson

Computer Science Technical Reports

In an Auslralian magazine, a monetary prize is awarded to the person with the best answer to a word puzzle called a Crozzle. Each valid placement of given words into a 10x 15 grid is given a score, and the best answer is the placement with the largest score. Various search techniques have been utilized lo solve this problem. No one has shown whether there is a polynomial-time algorithm to find the best Crozzle. This paper proves that the Crozzle is in NP. It also creates a similar word puzzle, called R-by-C Crozzle, by lifting the constraint on the grid …

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Computer-Aided Instruction In Dynamics: Does It Improve Learning?, Ralph E. Flori Nov 1994

Computer-Aided Instruction In Dynamics: Does It Improve Learning?, Ralph E. Flori

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Since 1992, the authors have been developing and testing BEST Dynamics software (Basic Engineering Software for Teaching Dynamics) with the goal of transforming how engineering dynamics is taught at the University of Missouri-Rolla, USA. This paper introduces the "BEST" Dynamics and its classroom implementation, raises questions concerning the cognitive impact of the software, attempts to classify the type of learning environment used in BEST Dynamics, and gives some new directions that are being taken based on the authors'' observations and experiences.

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Cosmological And Wormhole Solutions In Low-Energy Effective String Theory, Mariano Cadoni, Marco Cavaglia Nov 1994

Cosmological And Wormhole Solutions In Low-Energy Effective String Theory, Mariano Cadoni, Marco Cavaglia

Physics Faculty Research & Creative Works

We derive and study a class of cosmological and wormhole solutions of low-energy effective string field theory. We consider a general four-dimensional string effective action where moduli of the compactified manifold and the electromagnetic field are present. The cosmological solutions of the two-dimensional effective theory obtained by dimensional reduction of the former are discussed. In particular we demonstrate that the two-dimensional theory possesses a scale-factor duality invariance. Eucidean four-dimensional instantons describing the nucleation of the baby universes are found and the probability amplitude for the nucleation process given.

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Comment On "Critical Behavior Of The Coulomb Glass", Thomas Vojta, Michael Schreiber Nov 1994

Comment On "Critical Behavior Of The Coulomb Glass", Thomas Vojta, Michael Schreiber

Physics Faculty Research & Creative Works

No abstract provided.

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Method Of Manufacture Of Multiple-Element Piezoelectric Transducer, Lawrence J. Busse, Jeffry W. Stevenson, Wayne Huebner Nov 1994

Method Of Manufacture Of Multiple-Element Piezoelectric Transducer, Lawrence J. Busse, Jeffry W. Stevenson, Wayne Huebner

Materials Science and Engineering Faculty Research & Creative Works

An improved method for fabrication of a multiple-element piezoelectric transducer and the transducer produced thereby. A green precursor tape is produced by doctor-blade tape-casting of a slurry containing lead zirconate-titanate (PZT) powder. After drying, individual strips of the tape are stacked between flat plates of previously sintered PZT, and sintered to form PZT strips; Pb from the previously sintered PZT plates makes up any Pb lost from the surfaces of the tape strips during sintering. The PZT strips are stacked interposed by layers of a thermoplastic polymer, and heated to a temperature above the melting point of the polymer, forming …

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Neutron Diffraction And Mössbauer Effect Study Of Several Nd₂Fe₁₇₋ₓalₓ Solid Solutions, William B. Yelon, H. Xie, Gary J. Long, Oran Allan Pringle, Fernande Grandjean, K. H. J. Buschow Nov 1994

Neutron Diffraction And Mössbauer Effect Study Of Several Nd₂Fe₁₇₋ₓalₓ Solid Solutions, William B. Yelon, H. Xie, Gary J. Long, Oran Allan Pringle, Fernande Grandjean, K. H. J. Buschow

Physics Faculty Research & Creative Works

Aluminum-substituted Nd2Fe17-xAlx solid solutions with x=2.30, 4.44, 6.13, 8.00, and 9.40 have been studied by neutron diffraction and Mössbauer spectroscopy. A Rietveld analysis of the neutron scattering indicates that the aluminum atoms have a high initial affinity for the 18h site, show a high affinity for the 6c site at high aluminum concentrations, and are absent from the 9d site at all aluminum concentrations. The Mössbauer spectra show a maximum in both the maximum and weighted average hyperfine field for x≅2. This indicates that the lattice expansion which occurs with aluminum substitution is sufficient, at …

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Nature Of The Ferroelectric Phase Transition In Pbtio3, Noam Sicron, B. Ravel, Y. Yacoby, Edward A. Stern, Fatih Dogan, John J. Rehr Nov 1994

Nature Of The Ferroelectric Phase Transition In Pbtio3, Noam Sicron, B. Ravel, Y. Yacoby, Edward A. Stern, Fatih Dogan, John J. Rehr

Materials Science and Engineering Faculty Research & Creative Works

We have measured quantitatively the temperature dependence of the local distortions of PbTiO3 crystals below and above the structural ferroelectric phase transition, using x-ray absorption fine-structure (XAFS) measurements. Two probe atoms, Pb and Ti, were used. The results were analyzed by fitting parametrized theoretical XAFS spectra to the experimental results. These measurements provide quantitative ‘‘distortion parameters’’ defined as the difference between the distance of the probe to its nearest neighbor measured in the actual structure and that in a centrosymmetric structure with the same unit cell dimensions. At low temperatures the Pb-edge spectra were fit using four shells and included …

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Two-Dimensional Current Transient And Trap-State Filling Of Amorphous Silicon Thin-Film Transistors, J. S. Huang, Cheng-Hsiao Wu Nov 1994

Two-Dimensional Current Transient And Trap-State Filling Of Amorphous Silicon Thin-Film Transistors, J. S. Huang, Cheng-Hsiao Wu

Electrical and Computer Engineering Faculty Research & Creative Works

Two-dimensional simulations of amorphous silicon thin-film transistors are presented for the case when source-drain voltage is turned on long before gate voltage is turned on. Discrepancies between these results and the one-dimensional results of M. F. Willums, M. Hack, P. G. LeComber, and J. G. Shaw [MRS Symp. Proc. 258, 985 (1992)] are discussed. Valid reasons for drain current decay are provided, and occupation dynamics for the trap states are shown in order to distinguish these from the one-dimensional results of C. van Berkel, J. R. Hughes, and M. J. Powell [J. Appl. Phys. 66, 4488 (1989)] where …

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Performance Of Bandlimited Gaussian Noise As A Spreading Code In Awgn And Single Tone Interference Channels, Tze-Yu Chu, Kurt Louis Kosbar Nov 1994

Performance Of Bandlimited Gaussian Noise As A Spreading Code In Awgn And Single Tone Interference Channels, Tze-Yu Chu, Kurt Louis Kosbar

Electrical and Computer Engineering Faculty Research & Creative Works

This paper examines the bit error rate (BER) of a direct sequence spread spectrum (SS) system that uses bandlimited white Gaussian noise (BLWGN) as a spreading code. The performance of this "bandlimited-SS" system is examined in both additive white Gaussian noise (AWGN) and single tone jamming environments. The BLWGN spreading code is inferior to conventional codes in AWGN channels, but is more robust when a narrow band interference signal is present.

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Correlative Tracking Of Pseudo-Noise Codes Using A Phase Shifted Reference, Kurt Louis Kosbar, Hettiachchi Upul Gunawardana Nov 1994

Correlative Tracking Of Pseudo-Noise Codes Using A Phase Shifted Reference, Kurt Louis Kosbar, Hettiachchi Upul Gunawardana

Electrical and Computer Engineering Faculty Research & Creative Works

This work investigates a first-order correlation loop for tracking pseudo-noise (PN) codes. The local reference is produced by a PN sequence generator in series with a Hilbert transform filter. The tracking performance of this non-linear loop is compared with conventional early-late delay-lock loops (ELDLL). Using a conservative definition of bandwidth, the new loop was found to be superior at moderate to low signal-to-noise ratios (SNR). Another advantage of the new structure is that it has a very large (arguably infinite) lock range.

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The Missouri Miner, October 26, 1994 Oct 1994

The Missouri Miner, October 26, 1994

The Missouri Miner Newspaper

No abstract provided.

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The Missouri Miner, October 19, 1994 Oct 1994

The Missouri Miner, October 19, 1994

The Missouri Miner Newspaper

No abstract provided.

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A Design Procedure For Lipped Channel Flexural Members, Maria E. Moreyra, Teoman Pekoz Oct 1994

A Design Procedure For Lipped Channel Flexural Members, Maria E. Moreyra, Teoman Pekoz

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper is third in a series of three papers describing the research sponsored by the American Iron and Steel Institute. Physical test results described in the first paper combined with the finite element solution parametric studies described in the second paper were used in this paper to develop improved design procedures for edge stiffened elements.

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Local Buckling Of Stiffened And Unstiffened Elements Under Nonuniform Compression, Venkatakrishnan Kalyanaraman, P. Jayabalan Oct 1994

Local Buckling Of Stiffened And Unstiffened Elements Under Nonuniform Compression, Venkatakrishnan Kalyanaraman, P. Jayabalan

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Thin plates subjected to linearly varying inplane compression in one direction may undergo local buckling before failure. An analytical procedure is presented for evaluating the local buckling strength based on which equations for the local buckling stress of unstiffened and stiffened elements are presented.

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Behavior Of Connections Between Shs Columns & W-Section Beams, Uk Sun Kim, Jong Suk Lee, Young Bong Kwon Oct 1994

Behavior Of Connections Between Shs Columns & W-Section Beams, Uk Sun Kim, Jong Suk Lee, Young Bong Kwon

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Connections between SHS (Square Hollow Section) columns and W-section beams are generally fabricated by welding with or without endplates in the factory. These welded connections possess some finite degree of rotational stiffness which falls between fully rigid and ideally pinned joints. The influence of partially restrained connections on structural response not only changes the moment distribution but also increases frame drift. In this paper, a series of connection tests joining SHS column and W-section beam were executed and the test results compared with theoretical values. A method to utilize nonlinear moment-rotation relations of beam-to-column connections in steel framed structures is …

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Fatigue Behaviour Of Cold-Formed Steel Sections, Dimos Polyzois, Glenn Morris, S. K. Hassan Oct 1994

Fatigue Behaviour Of Cold-Formed Steel Sections, Dimos Polyzois, Glenn Morris, S. K. Hassan

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

In the expected life span of a transmission tower, the members are subjected to a large number of alternating wind applications. Fatigue behaviour due to repeated loading must therefore be considered in design. This paper presents the fatigue-test results for 52 cold-formed steel members. The results obtained can be used to establish additional guidelines for fatigue design of cold-formed steel sections.

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Pallet Racking Using Cold-Reduced Steel, J. S. Cowen, J. Michael Davies Oct 1994

Pallet Racking Using Cold-Reduced Steel, J. S. Cowen, J. Michael Davies

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Codes of practice for the design of cold-formed sections have generally included a requirement for the coil material to possess a specified amount of ductility prior to forming. The scientific basis for such ductility requirements is shrouded in historical mystery but code drafting committees have been reluctant to remove these requirements in the absence of good reason. However, very low ductility steels have been used for the manufacture of cold-formed steel components for many years by the two leading UK manufacturers of storage racks without this lack of ductility giving rise to any problems during either manufacture or service. This …

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Seismic Response Of Single-Storey Steel Buildings, R. Tremblay, S. F. Stiemer Oct 1994

Seismic Response Of Single-Storey Steel Buildings, R. Tremblay, S. F. Stiemer

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Nonlinear time step dynamic analyses have been performed on 24 rectangular single-storey steel framed buildings including a metal roof deck diaphragm and steel bracing bays along their exterior walls. The structures were designed according to current Canadian codes and were subjected to site specific ensembles of historical earthquake accelerograms. The analyses indicated that larger in-plane deformations and bending moments developed in the diaphragm compared to the values expected from the equivalent lateral force procedure commonly used in design. The distribution of the shear forces in the diaphragm was also found to deviate significantly from the linear distribution assumed in design. …

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