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1998

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Articles 1681 - 1710 of 2574

Full-Text Articles in Physical Sciences and Mathematics

Learning From Examples With Unspecified Attribute Values, Sally A. Goldman, Stephen S. Kwek, Stephen D. Scott Jan 1998

Learning From Examples With Unspecified Attribute Values, Sally A. Goldman, Stephen S. Kwek, Stephen D. Scott

All Computer Science and Engineering Research

We introduce the UAV learning model in which some of the attributes in the examples are unspecified. In our model, an example x is classified positive (resp., negative) if all possible assignments for the unspecified attributes result in a positive (resp., negative) classification. Otherwise the classificatoin given to x is "?" (for unknown). Given an example x in which some attributes are unspecified, the oracle UAV-MQ responds with the classification of x. Given a hypothesis h, the oracle UAV-EQ returns an example x (that could have unspecified attributes) for which h(x) is incorrect. We show that any class learnable in …


Subsurface Heavy-Metal Detection With The Use Of A Laser-Induced Breakdown Spectroscopy (Libs) Penetrometer System, Brian Miles, Javier Cortes Jan 1998

Subsurface Heavy-Metal Detection With The Use Of A Laser-Induced Breakdown Spectroscopy (Libs) Penetrometer System, Brian Miles, Javier Cortes

US Army Corps of Engineers

U.S. Army Engineer Waterways Experiment Station (WES) investigators have designed, fabricated, and demonstrated a cone penetrometer sensor for subsurface in situ field screening based on LIBS. The LIBS probe (patent pending) presented here is one of a suite of contaminant and geophysical probes developed by the WES Site Characterization and Analysis Penetrometer System (SCAPS) program. The LIBS probe includes a laser as part of the optical LIBS sensor section for metals analysis and a cone and sleeve soil classification module at its tip. Soil classification data are acquired during the push, while LIBS data are recorded during probe retraction, after …


Finite Rank Zᵈ Actions And The Loosely Bernoulli Property, Aimee S.A. Johnson, A. A. Şahin Jan 1998

Finite Rank Zᵈ Actions And The Loosely Bernoulli Property, Aimee S.A. Johnson, A. A. Şahin

Mathematics & Statistics Faculty Works

We define finite rank for Zᵈ actions and show that those finite rank actions with a certain tower shape are loosely Bernoulli for d ≥ 1.


Ecological Resilience, Biodiversity, And Scale, Garry D. Peterson, Craig R. Allen, C. S. Holling Jan 1998

Ecological Resilience, Biodiversity, And Scale, Garry D. Peterson, Craig R. Allen, C. S. Holling

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

We describe existing models of the relationship between species diversity and ecological function, and propose a conceptual model that relates species richness, ecological resilience, and scale.We suggest that species interact with scale-dependent sets of ecological structures and processes that determine functional opportunities. We propose that ecological resilience is generated by diverse, but overlapping, function within a scale and by apparently redundant species that operate at different scales, thereby reinforcing function across scales. The distribution of functional diversity within and across scales enables regeneration and renewal to occur following ecological disruption over a wide range of scales.


Ber-Based Call Admission In Wavelength-Routed Optical Networks, Debasish Datta, Byrav Ramamurthy, Helena Feng, Jonathan P. Heritage, Biswanath Mukherjee Jan 1998

Ber-Based Call Admission In Wavelength-Routed Optical Networks, Debasish Datta, Byrav Ramamurthy, Helena Feng, Jonathan P. Heritage, Biswanath Mukherjee

CSE Conference and Workshop Papers

Consider a wavelength-routed optical network in which nodes, i.e., multiwave length cross-connect switches (XCSs), are connected by fiber to form an arbitrary physical topology. A new call is admitted into the network if an all-optical lightpath can be established between the call’s source and destination nodes. Wavelength converters are assumed absent in this work.


Fractional Crystallization And Magma Mingling/Mixing Processes In The Monzonitic Association In The Sw Part Of The Composite Yozgat Batholith (Şefaatli-Yerköy, Sw Yozgat), Si̇bel Tatar, Durmuş Boztuğ Jan 1998

Fractional Crystallization And Magma Mingling/Mixing Processes In The Monzonitic Association In The Sw Part Of The Composite Yozgat Batholith (Şefaatli-Yerköy, Sw Yozgat), Si̇bel Tatar, Durmuş Boztuğ

Turkish Journal of Earth Sciences

The Yozgat batholith takes place in the passive margin of the Anatolide-Pontide convergence system. It includes; syn-collisional S-type, two-mica granites; post-collisional I-type, calcalkaline monzonitic association, and post-collisional, M-type, tholeiitic gabbroic/dioritic association. Among these associations, the monzonitic association is also subdivided into five mapable units such as Cankılı monzogabbro/monzodiorite, Akçakoyunlu quartz monzodiorite, Adatepe quartz monzonite, Yassiagil monzogranite and Karakaya monzogranite. All these subunits, except the Karakaya monzogranite, include K-feldspar megacrysts. These five subunits represent some evidence of fractional crystallization (FC) and magma mingling/mixing processes by means of field, mineralogical-petrographical and geochemical characteristics. There is a good zonation in the field that …


Tectono-Magmatic Evolution Of Alkaline Volcanics At Thekırka-Afyon-Isparta Structural Trend, Sw Turkey, M. Yilmaz Savaşcin, Tolga Oyman Jan 1998

Tectono-Magmatic Evolution Of Alkaline Volcanics At Thekırka-Afyon-Isparta Structural Trend, Sw Turkey, M. Yilmaz Savaşcin, Tolga Oyman

Turkish Journal of Earth Sciences

The youngest Alpine magmatism (Miocene to Quaternary) in Western and Central Anatolia is represented by three coeval assemblages from West to East. They are the Western Anatolian Volcanic assemblage (WAV), the N-S trending Kirka-Afyon-Isparta Alkaline Volcanic assemblage (KAIAV) and the Central Anatolian Volcanic Provinces (CAVP). The WAV and CAVP start with calc-alka-line volcanics and continue after Middle Miocene with shoshonitic to alkaline products of graben volcanism, while the KAIAV are all alkaline in character, without any former or later calc-alkaline contributions. The KAIAV are emplaced in three steps of alkaline vol-canic activities which exhibit southward younging along the N-S Kirka-Afyon-Isparta …


On The Action Of Steenrod Operations On Polynomial Algebras, İ. Karaca Jan 1998

On The Action Of Steenrod Operations On Polynomial Algebras, İ. Karaca

Turkish Journal of Mathematics

Let \( \bba \) be the mod-\( p \) Steenrod Algebra. Let \( p \) be an odd prime number and \( Z_{p} = Z/pZ \). Let \( P_{s} = Z_{p} [x_{1},x_{2},\ldots,x_{s}]. \) A polynomial \( N \in P_{s} \) is said to be hit if it is in the image of the action \( A \otimes P_{s} \ra P_{s}. \) In [10] for \( p=2, \) Wood showed that if \( \a(d+s) > s \) then every polynomial of degree \( d \) in \( P_{s} \) is hit where \( \a(d+s) \) denotes the number of ones in the …


On The Parabolic Class Number Of Some Subgroups Of Hecke Groups, R. Keski̇n Jan 1998

On The Parabolic Class Number Of Some Subgroups Of Hecke Groups, R. Keski̇n

Turkish Journal of Mathematics

In this paper we calculate the parabolic class number of subgroups of Hecke groups ( H(\sqrt{2}), H (\sqrt{3}) ).


Remote Sensing And Synchronous Land Surface Measurements Of Soil Moisture And Soil Temperature In The Field, N.V. Kolev, K.P. Penev, Y.M. Kirkova, B.S. Krustanov, T.G. Nazarsky, G.K. Dimitrov, C.P. Levchev, H.I. Prodanov, L.H. Kraleva Jan 1998

Remote Sensing And Synchronous Land Surface Measurements Of Soil Moisture And Soil Temperature In The Field, N.V. Kolev, K.P. Penev, Y.M. Kirkova, B.S. Krustanov, T.G. Nazarsky, G.K. Dimitrov, C.P. Levchev, H.I. Prodanov, L.H. Kraleva

Turkish Journal of Physics

The paper presents the results of remote sensing and synchronous land surface measurements for estimation of soil (surface and profile) water content and soil temperature for different soil types in Bulgaria. The relationship between radiometric temperature and soil surface water content is shown. The research is illustrated by some results from aircraft and land surface measurements carried out over three test areas near Pleven, Sofia and Plovdiv, respectively, during the period 1988-1990.


Elastic Scattering Of 344.5 Mev ^{12}C Ions From ^{11}B Nucleus, S.A.E. Khallaf, M.A. Abdel-Rahman, S.K. Abdel-Rahman, S.W.Z. Mahmoud Jan 1998

Elastic Scattering Of 344.5 Mev ^{12}C Ions From ^{11}B Nucleus, S.A.E. Khallaf, M.A. Abdel-Rahman, S.K. Abdel-Rahman, S.W.Z. Mahmoud

Turkish Journal of Physics

The angular distribution of the elastic scattering differential cross section of 344.5 MeV $^{12}$C ions from $^{11}$B nucleus is calculated and compared with the experimental data as well as the previously published calculations. The real part of the central optical potential is derived using the double-folding and single-folding procedures assuming Gaussian forms of the nucleon-nucleon and alpha-nucleon interactions, respectively. A nuclear matter density distribution function of $^{11}$B consisting of a spherical part plus a quadrupole term is used. The inclusion of the quadrupole term is found necessary to obtain good fits to the experimental data.


Space Charge Limited Current In Films Obtained In Glow Discharge Plasma, M.M. Akhmedov, M.K. Kerimov, B.A. Suleimanov, S.A. Mansimov Jan 1998

Space Charge Limited Current In Films Obtained In Glow Discharge Plasma, M.M. Akhmedov, M.K. Kerimov, B.A. Suleimanov, S.A. Mansimov

Turkish Journal of Physics

The electrical current in thin films obtained by the polymerization of acetonitrile in glow discharge on a heated substrate were investigated in order to determine the mechanism of electrical conduction. The results of the field dependence, sample thickness dependence of the dark conductivity, supported by the results of photocurrent measurements, suggest an exponential energy distribution of traps inside the band gap of the polymer.


The Great Alaskan Dinosaur Adventure, John Whitmore, Buddy Davis, Mike Liston Jan 1998

The Great Alaskan Dinosaur Adventure, John Whitmore, Buddy Davis, Mike Liston

Faculty Books

FIVE SOULS, huddled against the aching cold of the Alaskan wilderness. On a hunt for truth amid the shrieks of wild animals, the clouds, overhead race swiftly by?. Adventures from left to right: Mike Liston, Buddy Davis, Dan Specht, George Detwiler, and John Whitmore.

LOCKED in a remote, frozen wasteland where man has rarely been lie remains of creatures so mysterious, science can scarcely believe the truth.

A team of scientists and researchers endured incredible hardships to reach a site many would rather avoid?the Alaskan wilderness?and in the process, uncovered unfossilized dinosaur bones. The implications are enormous, for how can …


Speed Cut-Off Point For Antiforce Waves, Mostafa Hemmati, Mathues Shane Doss, Eric L. George Jan 1998

Speed Cut-Off Point For Antiforce Waves, Mostafa Hemmati, Mathues Shane Doss, Eric L. George

Journal of the Arkansas Academy of Science

A one-dimensional, three-component, fluid model has been employed to investigate the existence of a speed cut-off point for antiforce breakdown waves. The term antiforce wave is used to identify breakdown waves for which the electric field force on electrons is in the opposite direction of wave propagation. The electron fluid-dynamical equations for antiforce waves are different from those of proforce waves. This presentation will address the difference in the set of equations for proforce and antiforce waves and the method of integration of the set of equations through the dynamical transition region for antiforce waves. Also, for antiforce waves, the …


A Neutron Diffraction Structural Study Of R₂Fe₁₇₋ₓalx(C) (R=Tb,Ho) Alloys, William B. Yelon, H. Luo, Mingxing Chen, W. C. Chang, S. H. Tsai Jan 1998

A Neutron Diffraction Structural Study Of R₂Fe₁₇₋ₓalx(C) (R=Tb,Ho) Alloys, William B. Yelon, H. Luo, Mingxing Chen, W. C. Chang, S. H. Tsai

Physics Faculty Research & Creative Works

No abstract provided.


Neutron Diffraction And Frequency Dependence Of The A.C. Susceptibility Of The System Zncr₂Xal₂-₂Xs₄, M. Hamedoun, A. Hourmatallah, N. Benzakour, K. Mediouri, J. Ilali, William B. Yelon, H. Luo Jan 1998

Neutron Diffraction And Frequency Dependence Of The A.C. Susceptibility Of The System Zncr₂Xal₂-₂Xs₄, M. Hamedoun, A. Hourmatallah, N. Benzakour, K. Mediouri, J. Ilali, William B. Yelon, H. Luo

Physics Faculty Research & Creative Works

No abstract provided.


Magnetic And Thermal Properties Of Pr In La₁₋ₓprxbacacu₃O₇ System With 0.0, Rajvir Singh, S. Uma, E. Gmelin, William B. Yelon, V. P. S. Awana, S. X. Dou, A. V. Narlikar, Satish K. Malik Jan 1998

Magnetic And Thermal Properties Of Pr In La₁₋ₓprxbacacu₃O₇ System With 0.0, Rajvir Singh, S. Uma, E. Gmelin, William B. Yelon, V. P. S. Awana, S. X. Dou, A. V. Narlikar, Satish K. Malik

Physics Faculty Research & Creative Works

No abstract provided.


Pressure Induced Reversal Of The Volume Expansion Caused By Interstitial Nitrogen In Nd₂Fe₁₇N₃, R. Luo, William B. Yelon, Yusheng S.. Zhao, M. Ellouze, Ph. I'Héritier, G. K. Marasinghe, Peter C. Ezekwenna, R. B. Von Dreele, William Joseph James Jan 1998

Pressure Induced Reversal Of The Volume Expansion Caused By Interstitial Nitrogen In Nd₂Fe₁₇N₃, R. Luo, William B. Yelon, Yusheng S.. Zhao, M. Ellouze, Ph. I'Héritier, G. K. Marasinghe, Peter C. Ezekwenna, R. B. Von Dreele, William Joseph James

Physics Faculty Research & Creative Works

No abstract provided.


An Efficient Library For Parallel Ray Tracing And Animation, John Edward Stone Jan 1998

An Efficient Library For Parallel Ray Tracing And Animation, John Edward Stone

Masters Theses

"A parallel ray tracing library is presented for rendering high detail images of three dimensional geometry and computational fields. The library has been developed for use on distributed memory and shared memory parallel computers and can also run on sequential computers. Parallelism is achieved through the use of message passing and threads. It is shown that the library achieves almost linear scalability when run on large distributed memory parallel computers as well as large shared memory parallel computers.

Several applications of parallel rendering are explored including rendering of CAD models, animation, magnetic resonance imaging, and visualization of volumetric flow fields. …


Discussion Of: Lisa E. Wells, 1996. The Santa Beach Ridge Complex, Journal Of Coastal Research, 12(1), 1-17, Daniel H. Sandweiss, Kirk A. Maasch, Daniel F. Belknap, J. B. Richardson Iii, H. B. Rollins Jan 1998

Discussion Of: Lisa E. Wells, 1996. The Santa Beach Ridge Complex, Journal Of Coastal Research, 12(1), 1-17, Daniel H. Sandweiss, Kirk A. Maasch, Daniel F. Belknap, J. B. Richardson Iii, H. B. Rollins

Anthropology Faculty Scholarship

No abstract provided.


Sorting In Parallel, Ran Libeskind-Hadas Jan 1998

Sorting In Parallel, Ran Libeskind-Hadas

All HMC Faculty Publications and Research

In 1842, L.F. Menabrea anticipated the benefits of parallel computing in an article that appeared in the Swiss Journal Bibliotheque universelle de Geneve:

When a long series of identical computations is to be performed, such as those required for the formation of numerical tables, the machine can be brought into play so as to give several results at the same time, which will greatly abridge the whole amount of the processes.

Although more than a century passed before Menabrea's vision became a reality, today parallel computers with hundreds and even thousands of processors are used in a broad range …


Tree-Based Multicasting In Wormhole-Routed Irregular Topologies, Ran Libeskind-Hadas, Dominic Mazzoni '99, Ranjith Rajagopalan '99 Jan 1998

Tree-Based Multicasting In Wormhole-Routed Irregular Topologies, Ran Libeskind-Hadas, Dominic Mazzoni '99, Ranjith Rajagopalan '99

All HMC Faculty Publications and Research

A deadlock-free tree-based multicast routing algorithm is presented for all direct networks, regardless of interconnection topology. The algorithm delivers a message to any number of destinations using only a single startup phase. In contrast to existing tree-based schemes, this algorithm applies to all interconnection topologies, requires only fixed-sized input buffers that are independent of maximum message length, and uses a single asynchronous flit replication mechanism. The theoretical basis of the technique used here is sufficiently general to develop other tree-based multicasting algorithms for regular and irregular topologies. Simulation results demonstrate that this tree-based algorithm provides a very promising means of …


Design And Design Centers In Engineering Education, Clive L. Dym Jan 1998

Design And Design Centers In Engineering Education, Clive L. Dym

All HMC Faculty Publications and Research

This paper is intended to be the opening salvo of the workshop, Computing Futures in Engineering Design (Dym, 1997). Thus, I want to take this privileged moment to ask you to think with me about the role of design in engineering. In particular, I want to reflect upon how design is articulated and how design is taught; about the role of design in engineering education and in the practice of engineering; and about the role that could be played locally and, perhaps, nationally by a center devoted to design education. Because I teach here at Harvey Mudd College (HMC), …


Optimal Contention-Free Unicast-Based Multicasting In Switch-Based Networks Of Workstations, Ran Libeskind-Hadas, Dominic Mazzoni '99, Ranjith Rajagopalan '99 Jan 1998

Optimal Contention-Free Unicast-Based Multicasting In Switch-Based Networks Of Workstations, Ran Libeskind-Hadas, Dominic Mazzoni '99, Ranjith Rajagopalan '99

All HMC Faculty Publications and Research

A unicast-based multicasting algorithm is presented for arbitrary interconnection networks arising in switch-based networks of workstations. The algorithm is optimal with respect tot he number of startups incurred and is provably free from depth contention. Specifically, no two constituent unicasts for the same multicast contend for a common channel, even if some unicasts are delayed due to unpredictable variations in latencies. The algorithm uses an underlying partially adaptive deadlock-free unicast routing algorithm. Simulation results indicate that the algorithm behaves as predicted by its theoretical properties and provides a promising approach to unicast-based multicasting.


Distribution And Ecology Of The Morels And False Morels Of Iowa, L. H. Tiffany, G. Knaphus, D. M. Huffman Jan 1998

Distribution And Ecology Of The Morels And False Morels Of Iowa, L. H. Tiffany, G. Knaphus, D. M. Huffman

Journal of the Iowa Academy of Science: JIAS

The distribution, time of fruiting and habitats of morels and false morels in Iowa were documented during a 10 year survey (1984-1993). Distribution maps for each species also include information from published reports and from herbarium records. The true morel genus, Morchella, is represented in Iowa by five species. Three of these species, M. deliciosa, M. esculenta and M. crassipes, are sometimes interpreted as segments of one large, extremely variable species. M. semilibera and M. angusticeps also occur. M. angusticeps, a black morel, has not been previously reported from Iowa. Four false morels, two species in each of two genera, …


Editorial Board & Iowa Academy Of Science Officers And Directors Jan 1998

Editorial Board & Iowa Academy Of Science Officers And Directors

Journal of the Iowa Academy of Science: JIAS

No abstract provided.


Back Cover Jan 1998

Back Cover

Journal of the Iowa Academy of Science: JIAS

No abstract provided.


Cover - Perspectives On The Declining Flora And Fauna Of Iowa: A Symposium, Part 1 Jan 1998

Cover - Perspectives On The Declining Flora And Fauna Of Iowa: A Symposium, Part 1

Journal of the Iowa Academy of Science: JIAS

No abstract provided.


A Literature Review And Survey Of The Status Of Iowa's Terrestrial Flora, Deborah Q. Lewis Jan 1998

A Literature Review And Survey Of The Status Of Iowa's Terrestrial Flora, Deborah Q. Lewis

Journal of the Iowa Academy of Science: JIAS

A survey of Iowa's floristic literature and herbarium resources indicates that while there is not uniform coverage of plant groups and regions, a great deal is known about the Iowa flora. Taxonomic and floristic studies are ongoing, despite evidence of a decreased number of researchers with expertise and interest in Iowa's flora and changing emphases in academic research. Current knowledge is sufficient for the production of an Iowa Flora, and an Iowa Flora committee to initiate this project is proposed.


Editorial Board & Iowa Academy Of Science Officers And Directors Jan 1998

Editorial Board & Iowa Academy Of Science Officers And Directors

Journal of the Iowa Academy of Science: JIAS

No abstract provided.