Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

1995

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 1951 - 1980 of 2198

Full-Text Articles in Physical Sciences and Mathematics

Distributed Debugging With I/O Abstraction, Andrew S. Koransky Jan 1995

Distributed Debugging With I/O Abstraction, Andrew S. Koransky

All Computer Science and Engineering Research

This thesis presents a simple, yet powerful, set of mechanisms for testing and debugging distributed applications consisting of modules that communicate through well-defined data interfaces. The tools allow default or programmer-defined functions to be attached to various communication events so that particular data values at interesting points in the program are made available for testing and debugging. The debugging status of each component of the communication interface can be controlled separately so that various debugging information can be turned on and off during program execution. By attaching breakpoints to programmer-defined fucntions in a standard debugger, fine-grained examination of each module …

Go to article

Formal Specification Of A Dynamically Configurable Distributed System, Ram Sethuraman, Kenneth J. Goldman Jan 1995

Formal Specification Of A Dynamically Configurable Distributed System, Ram Sethuraman, Kenneth J. Goldman

All Computer Science and Engineering Research

The Programmers' Playground is a programming environment that supports end-user construction of distributed multimedia applications. The system implements a new programming model that is based, in part, upon ideas from the formal I/O automaton model of Lynch and Tuttle. Important features of The Programmers' Playground are a separation of communication and computation and graphical support for dynamic reconfiguration. This paper provides a formal specification of the Playground programming model and runtime system in terms of the I/O automaton model on which it is based. Exploiting the compositionality properties of the I/O automaton model, the formal specification is describd as a …

Go to article

Redesigning The Bsd Callout And Timer Facilities, Adam M. Costello, George Varghese Jan 1995

Redesigning The Bsd Callout And Timer Facilities, Adam M. Costello, George Varghese

All Computer Science and Engineering Research

We describe a new implementation of the BSD callout and timer facilities. Current BSD kernels take time proportional to the number of outstanding timers to set or cancel timers. Our implementation takes constant time to start, stop, and maintain timers; this leads to a highly scalable design that can support thousands of outstanding timers without much overhead. Unlike the existing implementation, our routines are guaranteed to lock out interrupts only for a small, bounded amount of time. We also extend the setitimer() interface to allow a process to have multiple outstanding timers, thereby reducing the need for users to maintain …

Go to article

User Interface Applications Of A Multi-Way Constraint Solver, T. Paul Mccartney Jan 1995

User Interface Applications Of A Multi-Way Constraint Solver, T. Paul Mccartney

All Computer Science and Engineering Research

Constraints are widely recognized as a useful tool for user interface constructino. Through constraints, relationships among user interface components can be defined declaratively, leaving the task of relationship management to a constraint solver. Multi-way constraint solvers supporting constraint hierarchies provide a means to specify preferential constraint relationships with a dynamically changing computation flow, making them especially well suited to interactive user interfaces. However, previous such constraint solvers lack the ability to enforce inequalities or to effectively handle cyclic constraint relationships. These deficiencies limit the problems that could be solved using a constraint-based approach. This paper presents a new algorithm called …

Go to article

Reasoning About Program Interactions In The Presence Of Mobility, Gruia-Catalin Roman, Peter J. Mccann Jan 1995

Reasoning About Program Interactions In The Presence Of Mobility, Gruia-Catalin Roman, Peter J. Mccann

All Computer Science and Engineering Research

Mobile computing is emerging as an important new paradigm which has the potential to reshape our thinking about distributed computation. Mobility has far-reaching implications on what designers and users can assume about communication patterns, resource availability, and applciation behaviors as components move from one location to another while joining or leaving groups of other components in their vicinity. New distributed algorithms are likely to be required as the nature of applications shifts with the emergence of this new kind of computing environment. Formal methods have an important role to play in the midst of these developments both in terms of …

Go to article

A General Matrix Iterative Model For Dynamic Load Balancing, Mark A. Franklin, Vasudha Govindan Jan 1995

A General Matrix Iterative Model For Dynamic Load Balancing, Mark A. Franklin, Vasudha Govindan

All Computer Science and Engineering Research

Effective load balancing algorithms are crucial in fully realizing the performance potential of parallel computer systems. This paper proposes a general matrix iterative model to represent a range of dynamic load balancing algorithms. The model and associated performance measures are used to evaluate and compare vairous load balancing algorithms and derive optimal algorithms and associated parameters for a given application and multiprocessor system. The model is parameterized to represent three load balancing algorithms - the random strategy, diffusion and complete redistribution algorithms. The model is validated by comparing the results with measured performance on a realistic workload. The parallel N-body …

Go to article

A Survey Of Network Signaling, Dakang Wu Jan 1995

A Survey Of Network Signaling, Dakang Wu

All Computer Science and Engineering Research

Abstract Network signaling is the process of transferring control information among components of a communication network to establish, maintain, and release connections, and to pass the network management information. The rapid evolution in the field of telecommunications has led to the rapid evolution of network signaling. In this paper, we review the evolution of network signaling. We emphasize the concepts and protocols used in modern fast packet switching networks especially in emerging ATM networks.

Go to article

Distributed Radiological Multimedia Conferencing, Naeem Bari Jan 1995

Distributed Radiological Multimedia Conferencing, Naeem Bari

All Computer Science and Engineering Research

Distributed Radiological Multimedia Conference (DRMC) is a collaborative imaging/multimedia conferencing tool which allows geographically separated physicians to confer over a shared projection radiograph. DRMC utilizes the advantages of high bandwidth and scalability offered by the new Asynchronous Transfer Mode (ATM) network technology. This application is customized for the high quality of displayed images and rapid response to user requests. It allows conferees to: share a common radiograph; each possess an independently controlled globally visible cursor; be able to point to and outline areas on the image to bring it to the other conferees' attention; and see and hear each other …

Go to article

Load Balance Properties Of Distributed Data Layouts For Clustered Mod Servers, Milind M. Buddhikot, Guru Parulkar Jan 1995

Load Balance Properties Of Distributed Data Layouts For Clustered Mod Servers, Milind M. Buddhikot, Guru Parulkar

All Computer Science and Engineering Research

Large scale storage servers that provide location transparent, interactive access to hundreds or thousands of concurrent, independent clients will be important components of hte furture information super-highway infrastructure. Two key requirements of such servers are as follows: support high parallelism and concurrency in data access to allow large number of access to the same or different data. Second, support independent interactive playout control operations such as fast-forward, rewind, slow-play, pause, resume, random access etc. with minimal latency. This paper assumes a distributed storage server architecture consisting of several high performance storage nodes interconnected by a high speed desk area network …

Go to article

Reliable Fifo Load Balancing Over Multiple Fifo Channels, Hari Adieseshu, Gurudatta M. Parulkar, George Varghese Jan 1995

Reliable Fifo Load Balancing Over Multiple Fifo Channels, Hari Adieseshu, Gurudatta M. Parulkar, George Varghese

All Computer Science and Engineering Research

Link striping algorithms are often used to overcome transmission bottlenecks in computer networks. However, traidtional striping algorithms suffer from two major disadvantages. They provide inadequate load sharing in the presence of variable length packets, and may result in non-FIFO delivery of data. We describe a new family of link striping algorithms that solve both problems. Our scheme applies to packets at any layer (physical, data, link, network, and transport) that work over multiple FIFO channels. We deal with variable sized packets by showing how a class of fair queueing algorithms can be converted into load sharing algorithms. Our transformation results …

Go to article

An Interactive Model Of Teaching, H. David Mathias Jan 1995

An Interactive Model Of Teaching, H. David Mathias

All Computer Science and Engineering Research

Previous teaching models in the learning theory community have been batch models. That is, in these models the teacher has generated a single set of helpful examples to present to the learner. In this paper we present an interactive model in which the learner has the ability to ask queries as in the query learning model of Angluin [1]. We show that this model is at least as powerful as previous teaching models. We also show that anything learnable with queries, even by a randomized learner, is teachable in our model. In all previous teaching models, all classes shown to …

Go to article

Self-Stabilization By Window Washing, Adam M. Costello, George Varghese Jan 1995

Self-Stabilization By Window Washing, Adam M. Costello, George Varghese

All Computer Science and Engineering Research

A useful way to design simple and robust protocols is to make them self-stabilitizing. We describe a new general technique for self-stabilization called window washing. We apply this technique to generalized sliding window protocols that work on a number of topologies. This results in simple, efficient, and self-stabilizing protocols. As far as we know, both window washing and generalized sliding window protocols are new ideas. Our protocols can be used for data links, reliable broadcast, and flow control.

Go to article

Assertional Reasoning About Pairwise Transient Interactions In Mobile Computing, Gruia-Catalin Roman, Peter J. Mccann, Jerome Plun Jan 1995

Assertional Reasoning About Pairwise Transient Interactions In Mobile Computing, Gruia-Catalin Roman, Peter J. Mccann, Jerome Plun

All Computer Science and Engineering Research

Mobile computing represents a major point of departure from the traditional distributed computing paradigm. The potentially very large number of independent computing units, a decoupled computing style, frequent disconnections, continuous position changes, and the location-dependent nature of the behavior and communication patterns of the individual components present designers with unprecedented challenges in the areas of modularity and dependability. This paper describes two ideas regarding a modular approach to specifying and reasoning about mobile computing. The novelty of our approach rests with the notion of allowing transient interactions among programs which mobe in space. In this paper we restrict our concert …

Go to article

Time Variability While Training A Parallel Neural Net Network, Tina L. Seawell, Barry L. Kalman Jan 1995

Time Variability While Training A Parallel Neural Net Network, Tina L. Seawell, Barry L. Kalman

All Computer Science and Engineering Research

The algorithmic analysis, data collection, and statistical analysis required to isolate the cause of time variability observed while an Elman style recurrent neural network is trained in parallel on a twenty processor SPARCcenter 2000 is described in detail. Correlations of system metrics indicate the operating system scheduler or an interaction of kernel processes is the most probable explanation for the variability.

Go to article

Euphoria: End-User Construction Of Direct Manipulation User Interfaces For Distributed Applications, T. Paul Mccartney, Kenneth J. Goldman, David E. Saff Jan 1995

Euphoria: End-User Construction Of Direct Manipulation User Interfaces For Distributed Applications, T. Paul Mccartney, Kenneth J. Goldman, David E. Saff

All Computer Science and Engineering Research

The Programmers' Playground is a software library and run-time system for creating distributed multimedia applications from collections of reusable software moduels. This paper presents the design and implementation of EUPHORIA, Playground's user interface management system. Implemented as a Playground module, EUPHORIA allows end-users to create direct manipulation graphical user interfaces (GUIs) exclusively through the use of a graphics editor. No programming is required. At run-time, attributes of the GUI state can be exposed and connected to external Playground modules, allowing the user to vosualize and directly manipulate state information in remote Playground modules. Features of EUPHORIA include real-time direct manipulation …

Go to article

Stafford County Shoreline Protection Report, Potomac River, Aquia Creek : Prepared For County Of Stafford, Department Of Planning And Community Development, Vhb : Vanasse, Hangen And Brustlin, Inc., Virginia Institute Of Marine Science Jan 1995

Stafford County Shoreline Protection Report, Potomac River, Aquia Creek : Prepared For County Of Stafford, Department Of Planning And Community Development, Vhb : Vanasse, Hangen And Brustlin, Inc., Virginia Institute Of Marine Science

Reports

No abstract provided.

Go to article

Evidence Of Active Dune Sand On The Great Plains In The 19th Century From Accounts Of Early Explorers, Daniel R. Muhs, Vance T. Holliday Jan 1995

Evidence Of Active Dune Sand On The Great Plains In The 19th Century From Accounts Of Early Explorers, Daniel R. Muhs, Vance T. Holliday

United States Geological Survey: Staff Publications

Eolian sand is extensive over the Great Plains of North America, but is at present mostly stabilized by vegetation. Accounts published by early explorers, however, indicate that at least parts of dune fields in Nebraska, Colorado, Kansas, New Mexico, and Texas were active in the 19th century. Based on an index of dune mobility and a regional tree-ring record, the probable causes for these periods of greater eolian activity are droughts, accompanied by higher temperatures, which greatly lowered the precipitationto- evapotranspiration ratio and diminished the cover of stabilizing vegetation. In addition, observations by several explorers, and previous historical studies, indicate …

Go to article

Geomorphic And Geochemical Evidence For The Source Of Sand In The Algodones Dunes, Colorado Desert, Southeastern California, Daniel R. Muhs, Charles A. Bush, Scott D. Cowherd, Shannon Mahan Jan 1995

Geomorphic And Geochemical Evidence For The Source Of Sand In The Algodones Dunes, Colorado Desert, Southeastern California, Daniel R. Muhs, Charles A. Bush, Scott D. Cowherd, Shannon Mahan

United States Geological Survey: Staff Publications

The Algodones dunes of southeastern California comprise one of the largest active dune fields in the United States. The source of sand of the Algodones dunes is controversial, and the source of stabilized aeolian sand in the adjacent East Mesa area has not been investigated at all. We used mineralogical compositions and trace element concentrations to ascertain the most likely source of sand for these active and stabilized dunes. Results indicate that alluvium derived from the San Bernardino Mountains, which enters the Salton trough to the northwest of the dune fields, and alluvium derived from the Chocolate Mountains, which is …

Go to article

Carbonate Deposition, Pyramid Lake Subbasin, Nevada: 2. Lake Levels And Polar Jet Stream Positions Reconstructed From Radiocarbon Ages And Elevations Of Carbonates (Tufas) Deposited In The Lahontan Basin, Larry Benson, Michaele Kashgarian, Meyer Rubin Jan 1995

Carbonate Deposition, Pyramid Lake Subbasin, Nevada: 2. Lake Levels And Polar Jet Stream Positions Reconstructed From Radiocarbon Ages And Elevations Of Carbonates (Tufas) Deposited In The Lahontan Basin, Larry Benson, Michaele Kashgarian, Meyer Rubin

United States Geological Survey: Staff Publications

Most of the tufas in the Pyramid Lake subbasin were deposited within the last 35,000 yr, including most of the mound tufas that border the existing lake. Many of the older tufas (> 21,000 yr B.P.) contained in the mounds were formed in association with ground-water discharge. The radiocarbon (14C) ages of the older tufas represent maximum estimates of the time of their formation. Lake Lahontan experienced large and abrupt rises in level at ~ 22,000, 15,000, and 11,000 yr B.P. and three abrupt recessions in level at ~ 16,000, 13,600, and 10,000 yr B.P. The lake-level rises …

Go to article

Constrained Least-Squares Digital Image Restoration, Rajeeb Hazra Jan 1995

Constrained Least-Squares Digital Image Restoration, Rajeeb Hazra

Dissertations, Theses, and Masters Projects

The design of a digital image restoration filter must address four concerns: the completeness of the underlying imaging system model, the validity of the restoration metric used to derive the filter, the computational efficiency of the algorithm for computing the filter values and the ability to apply the filter in the spatial domain. Consistent with these four concerns, this dissertation presents a constrained least-squares (CLS) restoration filter for digital image restoration. The CLS restoration filter is based on a comprehensive, continuous-input/discrete- processing/continuous-output (c/d/c) imaging system model that accounts for acquisition blur, spatial sampling, additive noise and imperfect image reconstruction. The …

Go to article

Spawning And Ecology Of Early Life Stages Of Black Drum, Pogonias Cormis, In Lower Chesapeake Bay, Louis Broaddus Daniel Iii Jan 1995

Spawning And Ecology Of Early Life Stages Of Black Drum, Pogonias Cormis, In Lower Chesapeake Bay, Louis Broaddus Daniel Iii

Dissertations, Theses, and Masters Projects

During spring 1990 and 1991, ichthyoplankton surveys were conducted in lower Chesapeake Bay to estimate seasonal egg production, population biomass and the impact of predation by gelatinous zooplankton on early life stages of black drum, Pogonias cromis. Rearing experiments indicated that at least three species of sciaenid (silver perch, Bairdiella chrysoura; weakfish, Cynoscion regalis and P. cromis) were spawning in the survey area during both years. Specific identification of eggs based on previously published ranges of outside egg diameter (OED) were not reliable due to considerable overlap in diameter distributions. Analysis of weekly OED frequency revealed the presence of three …

Go to article

Nutrition And Feeding In Striped Bass Morone Saxatilis Larvae: Lipid And Fatty Acid Requirements And Microencapsulated Diets, Sureyya Ozkizilcik Jan 1995

Nutrition And Feeding In Striped Bass Morone Saxatilis Larvae: Lipid And Fatty Acid Requirements And Microencapsulated Diets, Sureyya Ozkizilcik

Dissertations, Theses, and Masters Projects

There has been a growing interest in the commercial aquaculture of striped bass, Morone saxatilis. Little is known, however, about the nutritional requirements and feeding physiology of striped bass larvae. The objectives of this study were (a) to evaluate the efficiency of the live food enrichment techniques in studying the nutritional requirements for polyunsaturated fatty acids (PUFA), phospholipids and free amino acids, (b) to determine the ontogenetic changes of lipolytic enzymes, and (c) to develop a microencapsulated diet for striped bass larvae as full or partial replacement of live food. Three enrichment techniques, namely, microencapsulated fish oil, yeast/fish oil emulsion …

Go to article

Molecular Fluorescence Spectroscopy In The Vicinity Of A Microstructure, P.T. Leung, Thomas F. George Jan 1995

Molecular Fluorescence Spectroscopy In The Vicinity Of A Microstructure, P.T. Leung, Thomas F. George

Physics Faculty Publications and Presentations

A brief review is presented on fluorescence spectroscopy of molecules in the vicinity of a microstructure, which could be a surface structure, clustered ions/atoms, a colloidal particle in a solution, or a tip in certain molecular probes. This structure can be viewed as microscopic, mesoscopic or macroscopic, depending on the specific environment in which the molecule is located. An overview is given for selected experimental and theoretical aspects of this phenomenon, emphasizing some of the previous modeling work of the authors. Discussion of possible future attempts to explore the phenomenon in more detail is presented at the end.

Go to article

Student Evaluations Of Teaching Effectiveness: The Interpretation Of Observational Data And The Principle Of Faute De Mieux, B. Burt Gerstman Jan 1995

Student Evaluations Of Teaching Effectiveness: The Interpretation Of Observational Data And The Principle Of Faute De Mieux, B. Burt Gerstman

B. Burt Gerstman

Student opinion surveys are important but widely misunderstood tools for evaluating teaching effectiveness. In this brief review, an analogy is drawn between the use and interpretation of observational data for public health and biomedical research and the use of student opinion data in evaluating teach ing effectiveness. Sources of systematic error in the form of selection bias, information bias, and confounding are defined and illustrated. Original data concerning intermittent "quid pro quo" confounding (i.e., the effect of expected grades on student evaluations of teaching) are presented. Finally, the principle of faute de mieux ("lack of anything better") and the interpretation …

Go to article

A General Theory Of Geodesics With Applications To Hyperbolic Geometry, Deborah F. Logan Jan 1995

A General Theory Of Geodesics With Applications To Hyperbolic Geometry, Deborah F. Logan

UNF Graduate Theses and Dissertations

In this thesis, the geometry of curved surfaces is studied using the methods of differential geometry. The introduction of manifolds assists in the study of classical two-dimensional surfaces. To study the geometry of a surface a metric, or way to measure, is needed. By changing the metric on a surface, a new geometric surface can be obtained. On any surface, curves called geodesics play the role of "straight lines" in Euclidean space. These curves minimize distance locally but not necessarily globally. The curvature of a surface at each point p affects the behavior of geodesics and the construction of geometric …

Go to article

Error Analysis In Tidal Wetland Inventory Change Detection: Comparison Of Historical Mapped Wetlands Of The Achilles Quadrangle Between 1976 To 1989, Stacy A. C. Nelson Jan 1995

Error Analysis In Tidal Wetland Inventory Change Detection: Comparison Of Historical Mapped Wetlands Of The Achilles Quadrangle Between 1976 To 1989, Stacy A. C. Nelson

Dissertations, Theses, and Masters Projects

No abstract provided.

Go to article

The Geomorphology And Shallow Structure Of The Northeastern New Jersey Continental Slope, Nicole D. Scott Jan 1995

The Geomorphology And Shallow Structure Of The Northeastern New Jersey Continental Slope, Nicole D. Scott

Dissertations, Theses, and Masters Projects

No abstract provided.

Go to article

Filtration Of Oysters In Patches: Effects Of Water Flow And Seston Composition, Deborah Armitage Harsh Jan 1995

Filtration Of Oysters In Patches: Effects Of Water Flow And Seston Composition, Deborah Armitage Harsh

Dissertations, Theses, and Masters Projects

No abstract provided.

Go to article

High-Resolution Seismic Stratigraphy Of The Ganges-Brahmaputra River System: Subaqueous Deltaic Progradation On The Bengal Shelf, Beth Michele Levy Jan 1995

High-Resolution Seismic Stratigraphy Of The Ganges-Brahmaputra River System: Subaqueous Deltaic Progradation On The Bengal Shelf, Beth Michele Levy

Dissertations, Theses, and Masters Projects

No abstract provided.

Go to article

An Analysis Of Wetland Total Phosphorus Retention And Watershed Structure, Megan K. Greiner Jan 1995

An Analysis Of Wetland Total Phosphorus Retention And Watershed Structure, Megan K. Greiner

Dissertations, Theses, and Masters Projects

No abstract provided.

Go to article

First Prev Next Last