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1996

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Articles 1621 - 1650 of 2437

Full-Text Articles in Physical Sciences and Mathematics

Teaching And Evaluating Outdoor Ethics Programs: Setting A Research Agenda, Bruce E. Matthews Jan 1996

Teaching And Evaluating Outdoor Ethics Programs: Setting A Research Agenda, Bruce E. Matthews

Research in Outdoor Education

No abstract provided.

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Personality Preferences Of Outdoor Participants, Christine Cashel, Diane Montgomery, Suzie Lane Jan 1996

Personality Preferences Of Outdoor Participants, Christine Cashel, Diane Montgomery, Suzie Lane

Research in Outdoor Education

There remains some question about how to link what is known about individuals to the planning and implementation of group struc­tured outdoor programs. One theory that may illuminate the program planning and imple­mentation processes in terms of collective dif­ferences is Jungian personality theory.

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Coe Fliers From Proceedings, Coalition For Education In The Outdoors (Ceo) Jan 1996

Coe Fliers From Proceedings, Coalition For Education In The Outdoors (Ceo)

Research in Outdoor Education

Information on joining COE or subscribing to Taproot are included here. They were originally included at the end of the Proceedings.

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A Group Of Galaxies At Redshift 2.38, Paul J. Francis, Bruce E. Woodgate, Stephen J. Warren, Palle Møller, Margaret Mazzolini, Andrew J. Bunker, James D. Lowenthal, Ted B. Williams, Takeo Minezaki, Yukiyasu Kobayashi, Yuzuru Yoshii Jan 1996

A Group Of Galaxies At Redshift 2.38, Paul J. Francis, Bruce E. Woodgate, Stephen J. Warren, Palle Møller, Margaret Mazzolini, Andrew J. Bunker, James D. Lowenthal, Ted B. Williams, Takeo Minezaki, Yukiyasu Kobayashi, Yuzuru Yoshii

Astronomy: Faculty Publications

We report the discovery of a group of galaxies at redshift 2.38. We imaged ∼ 10% of a claimed supercluster of QSO absorption lines at z = 2.38. In this small field (2′ radius), we detect two Lyα-emitting galaxies. The discovery of two such galaxies in our tiny field supports Francis & Hewett's interpretation of the absorption-line supercluster as a high-redshift Great Wall. One of the Lyα galaxies lies 22″ from a background QSO and may be associated with a multicomponent Lyα absorption complex seen in the QSO spectrum. This galaxy has an extended (∼50 kpc), lumpy Lyα morphology surrounding …

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Optimal Solution Of Off-Line And On-Line Generalized Caching, Saied Hosseini-Khayat, Jerome R. Cox Jan 1996

Optimal Solution Of Off-Line And On-Line Generalized Caching, Saied Hosseini-Khayat, Jerome R. Cox

All Computer Science and Engineering Research

Network traffic can be reduced significantly if caching is utilized effectively. As an effort in this direction we study the replacement problem that arises in caching of multimedia objects. The size of objects and the cost of cache misses are assumed non-uniform. The non-uniformity of size is inherent in multimedia objects, and the non-uniformity of cost is due to the non-uniformity of size and the fact that the objects are scattered throughout the network. Although a special case of this problem, i.e. the case of uniform size and cost, has been extensively studied, the general case needs a great deal …

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End-User Construction And Configuration Of Distributed Multimedia Applications, Terrance Paul Mccartney Jan 1996

End-User Construction And Configuration Of Distributed Multimedia Applications, Terrance Paul Mccartney

All Computer Science and Engineering Research

Distributed multimedia applications supported by a global electronic infrastructure have tremendous potential for providing users with customized communication and computation environments. Since communication and computation requirements vary by context and change dynamically, it is unlikely that off-the-shelf applications will anticipate the needs of all users. Therefore, empowering end-users to create their own customized applications for both communication and computation is an important challenge. This dissertation presents several mechanisms that enable end-users to create and configure distributed multimedia applications, including end-users construction direct manipulation graphical users interface (GUIs) and application management of distributed multimedia applications over the Internet.

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The Angular Distribution Of Comptel Gamma-Ray Bursts, R M. Kippen, James M. Ryan, A Connors, Mark L. Mcconnell, H Hartmann, C Winkler, L O. Hanlon, V Schonfelder, J Greiner, M Varendorff, W Collmar, W Hermsen, L Kuiper Jan 1996

The Angular Distribution Of Comptel Gamma-Ray Bursts, R M. Kippen, James M. Ryan, A Connors, Mark L. Mcconnell, H Hartmann, C Winkler, L O. Hanlon, V Schonfelder, J Greiner, M Varendorff, W Collmar, W Hermsen, L Kuiper

Space Science Center

The superior burst location capability of the COMPTEL instrument aboard the Compton Gamma-Ray Observatory allows us to study the small-scale angular distribution of burst sources with good sensitivity even though the number of burst detections is small. We accumulate four years (April 1991–April 1995) of observations to form a catalog of 27 burst locations whose mean 1σ uncertainty is ∼1°. We find that the COMPTEL bursts are consistent with an isotropic distribution of sources, yet the spatial coincidence of two of the bursts within COMPTEL’s angular resolution indicates the possibility of repetition. This possibility is studied using the two-point angular …

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Using Batse To Measure Gamma-Ray Burst Polarization, Mark L. Mcconnell, D J. Forrest, W T. Vestrand, M H. Finger Jan 1996

Using Batse To Measure Gamma-Ray Burst Polarization, Mark L. Mcconnell, D J. Forrest, W T. Vestrand, M H. Finger

Space Science Center

We describe a technique for measuring the polarization of hard x-rays from γ-ray bursts based on the angular distribution of that portion of the flux which is scattered off the top of the Earth’s atmosphere. The scattering cross section depends not only on the scatter angle itself, but on the orientation of the scatter angle with respect to the incident polarization vector. Consequently, the distribution of the observed albedo flux will depend on the direction and the polarization properties (i.e., the level of polarization and polarization angle) of the source. Although the BATSE design (with its large field-of-view for each …

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Looking For The Source Of ∼Hour-Long Soft X-Ray Emission Following Grb 780506, A Connors, Mark L. Mcconnell Jan 1996

Looking For The Source Of ∼Hour-Long Soft X-Ray Emission Following Grb 780506, A Connors, Mark L. Mcconnell

Space Science Center

GRB 780506, a gamma-ray burst discovered in HEAO 1 A-4 data, was unusual in three respects. First, it was well-measured (by HEAO 1 A-2) in 2–60 keV X-rays. Second, two minutes after it ended, HEAO 1 A-2 detected a faint resurgence of 2–10 keV flux, lasting roughly an hour. From recently calculated position constraints, it appears the source of the extended flux is consistent with the source of the burst, and probably not from a serendipitous transient along the Galactic plane. Third, it now appears GRB 780506 belongs to a newly discovered softer subclass of gamma-rays bursts. This subclass is …

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Extended Γ‐Ray Emission In Solar Flares, G Rank, K Bennett, H Bloemen, H Debrunner, J Lockwood, Mark L. Mcconnell, James M. Ryan, V Schonfelder, R Suleiman Jan 1996

Extended Γ‐Ray Emission In Solar Flares, G Rank, K Bennett, H Bloemen, H Debrunner, J Lockwood, Mark L. Mcconnell, James M. Ryan, V Schonfelder, R Suleiman

Space Science Center

During the solar flare events on 11 and 15 June 1991, COMPTEL measured extended emission in the neutron capture line for about 5 hours after the impulsive phase. The time profiles can be described by a double exponential decay with decay constants on the order of 10 min for the fast and 200 min for the slow component. Within the statistical uncertainty both flares show the same long‐term behaviour. The spectrum during the extended phase is significantly harder than during the impulsive phase and pions are not produced in significant numbers before the beginning of the extended emission. Our results …

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Comptel Solar Flare Measurements, James M. Ryan, Mark L. Mcconnell Jan 1996

Comptel Solar Flare Measurements, James M. Ryan, Mark L. Mcconnell

Space Science Center

We review some of the highlights of the COMPTEL measurements of solar flares. These include images of the Sun in γ rays and neutrons. One of the important features of the COMPTEL instrument is its capability to measure weak fluxes of γ rays and neutrons in the extended phase of flares. These data complement the spectra taken with the COMPTEL burst spectrometer and the telescope during the impulsive phase of flares. We focus our attention on some of these general capabilities of the instrument and the latest results of two long‐duration γ‐ray flares, i.e., 11 and 15 June 1991

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The Δ Scuti Star Fg Virginis Ii. A Search For High Pulsation Frequencies, Michel Breger, Matt A. Wood Jan 1996

The Δ Scuti Star Fg Virginis Ii. A Search For High Pulsation Frequencies, Michel Breger, Matt A. Wood

Aerospace, Physics, and Space Science Faculty Publications

Although the δ Scuti and roAp variables occupy similar positions on and near the main sequence, δ Scuti variables pulsate with lower radial and nonradial overtones and lower frequencies. To test whether high frequencies (as found in the roAp stars) are also present in δ Scuti stars, a multisite campaign with the Whole Earth Telescope (WET) was carried out for the star FG Vir. The 96.7 hours of WET photometry were supplemented by measurements made with the Delta Scuti Network (DSN), because the DSN technique includes regular measurements of comparison stars and is better suited to monitoring the low frequencies …

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On The Structure Of The Deflagration For The Generalized Reaction-Rate Model, William B. Bush, L. Krishnamurthy Jan 1996

On The Structure Of The Deflagration For The Generalized Reaction-Rate Model, William B. Bush, L. Krishnamurthy

Mathematics and System Engineering Faculty Publications

The structure of the deflagration is examined by means of an asymptotic analysis of the physical-plane boundary-value problem, with Lewis-Semenov number unity, in the limit of the activation-temperature ratio, β = Ta/Tb, greater than order unity, for the generalized reaction-rate-model case of (1) the heat- addition-temperature ratio, α = (Tb — Tu)/Tu, of order unity [where Ta, Tb, and Tu are the activation, adiabatic-flame (and/or burned-gas), and unburned-gas temperatures, respectively]; and (2) the exponent, a, which characterizes the pre-exponential thermal dependence of the reaction-rate term, unity. This examination indicates that the deflagration has a four-region structure. To obtain a uniformly …

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Security Issues In Mobile Information Networks, Thomas Hardjono, Jennifer Seberry Jan 1996

Security Issues In Mobile Information Networks, Thomas Hardjono, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

During the last decade the decrease in the size of computing machinery, coupled with the increase in their computing power has lend to the development of the concept of mobile computing. Effects of this new vision is currently evident in the flourishing numbers of mobile telephones and portable computing units. In this paper we briefly investigate some issues concerning the security of mobile computing systems, within the framework of the categories of mobility, disconnection, data access modes and scale of operation (Imielinski & Badrinath, 1993). In contrast to previous works which concentrate on security in wireless communications, we focus on …

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Beacons For Authentication In Distributed Systems, Azad Jiwa, Thomas Hardjono, Jennifer Seberry Jan 1996

Beacons For Authentication In Distributed Systems, Azad Jiwa, Thomas Hardjono, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

Reliable authentication of communicating entities is essential for achieving security in a distributed computing environment. The design of such systems as Kerberos, SPX and more recently KryptoKnight and Kuperee, have largely been successful in addressing the problem. The common element with these implementations is the need for a trusted third-party authentication service. This essentially requires a great deal of trust to be invested in the authentication server which adds a level of complexity and reduces system flexibility. The use of a Beacon to promote trust between communicating parties was first suggested by M. Rabin in "Transactions protected by beacons", Journal …

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New Weighing Matrices, Christos Koukouvinos, Jennifer Seberry Jan 1996

New Weighing Matrices, Christos Koukouvinos, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

New weighing matrices and skew weighing matrices are given for many orders 4t ≤ 100. These are constructed by finding new sequences with zero autocorrelation. These results enable us to determine for the first time that for 4t ≤ 84 a W{4t,k) exists for all k = 1, ... ,4t -1 and also that there exists a skew-weighing matrix (also written as an OD(4t;1,k)) for 4t ≤ 80, t odd, k = a2 + b2 + c2,a,b,c integers except k = 4t - 2 must be the sum of two squares.

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On Sufficient Conditions For Some Orthogonal Designs And Sequences With Zero Autocorrelation Function, C. Koukouvinos, M. Mitrouli, Jennifer Seberry, P. Karabelas Jan 1996

On Sufficient Conditions For Some Orthogonal Designs And Sequences With Zero Autocorrelation Function, C. Koukouvinos, M. Mitrouli, Jennifer Seberry, P. Karabelas

Faculty of Informatics - Papers (Archive)

We give new sets of sequences with entries from {0, ±a, ±b, ±c, ±d} on the commuting variables a, b, c, d and zero autocorrelation function. Then we use these sequences to construct some new orthogonal designs. This means that for order 28 only the existence of the following five cases, none of which is ruled out by known theoretical results, remain in doubt: OD(28; 1, 4, 9, 9), OD(28; 1, 8, 8, 9), OD(28; 2, 8, 9, 9), OD(28; 3, 6, 8, 9), OD(28; 4, 4, 4, 9). We consider 4 - N PAF(Sl, S2, …

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Necessary And Sufficient Conditions For Some Two Variable Orthogonal Designs In Order 36, Christos Koukouvinos, Nikos Platis, Jennifer Seberry Jan 1996

Necessary And Sufficient Conditions For Some Two Variable Orthogonal Designs In Order 36, Christos Koukouvinos, Nikos Platis, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

We give new sets of sequences with entries from {0, ±a, ±b, ±c, ±d} on the commuting variables a, b, c, d with zero autocorrelation function. We show that the necessary conditions are sufficient for the existence two variable orthogonal designs constructed from circulant matrices in order 36. Further we show that the necessary conditions for the existence of an OD(36;S1,S2) are sufficient except possibly for the following five cases: (3,29) (11,20) (11,21) (13,19) (15,17).

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On The Smith Normal Form Of D-Optimal Designs, Christos Koukouvinos, M. Mitrouli, Jennifer Seberry Jan 1996

On The Smith Normal Form Of D-Optimal Designs, Christos Koukouvinos, M. Mitrouli, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

The Smith normal forms (SNF) of V-optimal designs of size < 100 are determined by a computer search. A theorem is given for the SNF of V-optimal designs of order 4t + 2 when 4t + 1 is square free, and bounds for the minimum number of 2's which can appear in the SNF are derived.

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Multiplication Of Ternary Complementary Pairs, Marc Gysin, Jennifer Seberry Jan 1996

Multiplication Of Ternary Complementary Pairs, Marc Gysin, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

We present a computer-search method for concatenating or "multiplying" binary or ternary complementary pairs. All multiplications by a particular number m are considered. The computer-search method is new and leads to a large set of new results. The results and equivalences are discussed and some applications and numerical consequences are shown.

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Minimal And Maximal Critical Sets In Room Squares, Ghulam Rasool Chaudhry, Jennifer Seberry Jan 1996

Minimal And Maximal Critical Sets In Room Squares, Ghulam Rasool Chaudhry, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

In this paper we introduce critical sets in Room squares. We give the cardinality of the minimal critical sets (min. cs) and maximal critical sets (max. cs) for inequivalence classes of Room squares of side 7,9, and 11. We also describe algorithms to compute min. cs and max. cs and conjecture the lower and upper bounds for min. cs and max. cs.

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Shared Cryptographic Bits Via Quantized Quandrature Phase Amplitudes Of Light, Yi Mu, Jennifer Seberry, Yuliang Zheng Jan 1996

Shared Cryptographic Bits Via Quantized Quandrature Phase Amplitudes Of Light, Yi Mu, Jennifer Seberry, Yuliang Zheng

Faculty of Informatics - Papers (Archive)

We propose a novel quantum cryptographic protocol without using polarized photons. The protocol consists of an optical coupler and four nonorthogonal coherent states which are analyzed by means of quadrature phase amplitudes of quantized light field.

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Replicating The Kuperee Authentication Server For Increased Security And Reliability, Thomas Hardjono Jan 1996

Replicating The Kuperee Authentication Server For Increased Security And Reliability, Thomas Hardjono

Faculty of Informatics - Papers (Archive)

The current work proposes a new scheme for the replication of authentication services in Kuperee based on a public key cryptosystem, in response to the two main shortcomings of the traditional single server solutions, namely those of low availability and high security risks. The work represents further developments in the Kuperee authentication system. The Kuperee server is presented in its simplified design to aid the presentation of the replication scheme. The replication approach is based on the sharing of session public keys, together with a threshold or secret sharing scheme. However, unlike previous approaches, in the current work the object …

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Secret Sharing Schemes Based On Room Squares, Ghulam Rasool Chaudhry, Jennifer Seberry Jan 1996

Secret Sharing Schemes Based On Room Squares, Ghulam Rasool Chaudhry, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

In this paper, we describe secret sharing schemes. We discuss Room squares and their critical sets. We propose a model of sharing based on critical sets of Room squares.

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Design And Security Issues In Strongbox Systems For The Internet, Thomas Hardjono, Jennifer Seberry Jan 1996

Design And Security Issues In Strongbox Systems For The Internet, Thomas Hardjono, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

This paper presents and discusses some design and security issues surrounding electronic strongboxes as an electronic counterpart of physical strongboxes typically found in large traditional financial institutions. The concept of electronic strongboxes is briefly discussed, comparing against physical strongboxes. A basic system for electronic strongboxes is then provided and the functional and security requirements of the system's components is presented.

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Strong Boxes For Electronic Commerce, Thomas Hardjono, Jennifer Seberry Jan 1996

Strong Boxes For Electronic Commerce, Thomas Hardjono, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

As electronic commerce becomes a reality, additional services related to electronic commerce will also emerge. The current paper proposes the provision of electronic strongboxes as an integrated part of the wider electronic commerce. The strongbox concept is introduced as an electronic counterpart of physical strongboxes typically found in large traditional financial institutions, such as banks, having secure vaults or other secure physical storage. The work identifies some requirements of electronic strongboxes both from the functionality perspective and from the security point of view. A simple framework for an electronic strongbox system is also presented.

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Triangle Buildings And Actions Of Type Iii 1/Q2, Jacqueline Ramagge, Guyan Robertson Jan 1996

Triangle Buildings And Actions Of Type Iii 1/Q2, Jacqueline Ramagge, Guyan Robertson

Faculty of Informatics - Papers (Archive)

We study certain group actions on triangle buildings and their boundaries and some von Neumann algebras which can be constructed from them. In particular, for buildings of order q ≥ 3 certain natural actions on the boundary are hyperfinite of type III1/q2.

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New Wavelet Based Art Network For Texture Classification, Jiazhao Wang, Golshah Naghdy, Philip O. Ogunbona Jan 1996

New Wavelet Based Art Network For Texture Classification, Jiazhao Wang, Golshah Naghdy, Philip O. Ogunbona

Faculty of Informatics - Papers (Archive)

A new method for texture classification is proposed. It is composed of two processing stages, namely, a low level evolutionary feature extraction based on Gabor wavelets and a high level neural network based pattern recognition. This resembles the process involved in the human visual system. Gabor wavelets are exploited as the feature extractor. A neural network, Fuzzy Adaptive Resonance Theory (Fuzzy ART), acts as the high level decision making and recognition system. Some modifications to the Fuzzy ART make it capable of simulating the post-natal and evolutionary development of the human visual system. The proposed system has been evaluated using …

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Texture Analysis Using Gabor Wavelets, Golshah Naghdy, Jianli Wang, Philip Ogunbona Jan 1996

Texture Analysis Using Gabor Wavelets, Golshah Naghdy, Jianli Wang, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

Receptive field profiles of simple cells in the visual cortex have been shown to resemble even- symmetric or odd-symmetric Gabor filters. Computational models employed in the analysis of textures have been motivated by two-dimensional Gabor functions arranged in a multi-channel architecture. More recently wavelets have emerged as a powerful tool for non-stationary signal analysis capable of encoding scale-space information efficiently. A multi-resolution implementation in the form of a dyadic decomposition of the signal of interest has been popularized by many researchers. In this paper, Gabor wavelet configured in a 'rosette' fashion is used as a multi-channel filter-bank feature extractor for …

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Differentiate And Make Waves, R. Nillsen Jan 1996

Differentiate And Make Waves, R. Nillsen

Faculty of Informatics - Papers (Archive)

In 1972 Gary Meisters and Wolfgang Schmidt showed that if the Fourier coefficient of a function is zero at the origin, then the function is a sum of three first order differences. They deduced from this that every translation invariant linear form on the space of square integrable functions on the circle group is automatically continuous. Their results were subsequently developed by the author for the case of n-dimensional Euclidean space (Lectures Notes in Mathematics, vol. 1586, Springer-Verlag,1994). The present paper gives an exposition of some of the ideas in this work, with the aim of minimising the technicalities. In …

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