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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.

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An Efficient Signaling Structure For Atm Networks, Dakang Wu Jan 1995

An Efficient Signaling Structure For Atm Networks, Dakang Wu

All Computer Science and Engineering Research

As ATM becomes widely accepted as the communication standard for high speed networks, the signaling system structure and protocols that support ATM become more and more important. To support existing, future and unknown applications, the signalign system has to be very flexible and efficient. In this paper we define the signaling problem, present several possible signaling system structures, compare the advantages and disadvantages of these systems, and then we propose a new signaling system structure. The fundamental idea of the new signaling system is the logical separation of the signaling system structure from the underlying communication network, even though they …

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Pac Learing Of One-Dimensional Patterns, Paul W. Goldberg, Sally A. Goldman, Stephen D. Scott Jan 1995

Pac Learing Of One-Dimensional Patterns, Paul W. Goldberg, Sally A. Goldman, Stephen D. Scott

All Computer Science and Engineering Research

Developing the ability to recognize a landmark from a visual image of a robot's current location is a fundamental problem in robotics. We consider the problem of PAC-learning the concept class of geometric patterns where the target geometric pattern is a configuration of k points on the real line. Each instance is a configuration of n points on the real line, where it is labeled according to whether or not it visually resembles the target pattern. To capture the notion of visual resemblance we use the Hausdorff metric. Informally, two geometric patterns P and Q resemble each othe runder the …

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Issues In Distributed Control For Atm Networks, Jonathan S. Turner Jan 1995

Issues In Distributed Control For Atm Networks, Jonathan S. Turner

All Computer Science and Engineering Research

Asynchronous Transfer Mode (ATM) network technology is expected to become a central part of the emerging global information infrastructure. ATM networks introduce a number of features that distinguish them from earlier technologies and introduce new issues in network control. This paper offers a framework for precisely defining and analyzing alternative approaches to the distributed control of ATM networks and explores some of the key design issues through a series of examples. It is hoped that it will provide a useful foundation for researchers in networking and distributed computing interested in exploring these issues further and developing more complete solutions.

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Synchronized Data Objects, Marin Bezic Jan 1995

Synchronized Data Objects, Marin Bezic

All Computer Science and Engineering Research

Synchronized Data Objects (SDOs) are presented as a method of encapsulating, in the datatype definition, synchronization protocols that are used to control information exchange. SDOs are presented in the context of I/O abstraction, a programming model that seeks to separate communication from computation in order to support dynamic end-user configuration of distrivuted applications. SDOs can be used to implement a variety of synchronization paradigms, including remote invalidation, demand-driven data streams, remote procedure call, and promises. An implementation of SDOs is described in the context of The Programmers' Playground, a distributed application development environment that supports the I/O abstraction programming model. …

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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 …

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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 …

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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 …

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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.

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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 …

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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 …

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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 …

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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 …

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Design Of A Tool For Rapid Prototyping Of Communication Protocols, Aniruddha Gokhale, Ron Cytron, George Varghese Jan 1995

Design Of A Tool For Rapid Prototyping Of Communication Protocols, Aniruddha Gokhale, Ron Cytron, George Varghese

All Computer Science and Engineering Research

We present a new tool for automatically generating prototypes of communication protocols on a wide variety of platforms. Our goal is to reduce design time, enhance portability, and accommodate optimizations automatically. Users of the tool are required to provide an abstract implementation of the protocol in C++ without worrying about the underlying operating system specific system calls. Instead, the user employs high-level interface functions provided by the tool to interact with the underlying operating system. Users also need not worry about complex packet formats that involve fields of various bit and byte lengths. Instead, they use simple C/C++ struct declarations …

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An Oo Encapsulation Of Lightweight Os Concurrency Mechanisms In The Ace Toolkit, Douglas C. Schmidt Jan 1995

An Oo Encapsulation Of Lightweight Os Concurrency Mechanisms In The Ace Toolkit, Douglas C. Schmidt

All Computer Science and Engineering Research

This paper describes the design of the ACE object-oriented thread encapsulation class library. The architecture of this class library is presented from an end-user and internal design perspective and several key design issues are discussed. Readers should gain an understanding of the overall design approach as well as the tradeoffs between various software quality factors such as performance, portability, and extensibility.

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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 …

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Error Control For Continuous Media And Multipoint Applications, Christos Papadopoulos, Guru Parulkar Jan 1995

Error Control For Continuous Media And Multipoint Applications, Christos Papadopoulos, Guru Parulkar

All Computer Science and Engineering Research

High-bandwidth multimedia applications pose new challenges to error control. These include the support of error control for Continuous Media (CM) streams and the scalable support of error control in multipoint applications where the number of participants is large. Current error control mechanisms provide no support for the above applications. In this report we present new error control mechanisms that provide the required support. Continuous media applications have strict timing requirements which greatly affect recovery. To support continuous media applications we have designed and implemented a point-to-point error control mechanism which features the following: (1) selective repeat retransmission, (2) conditional retransmission, …

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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 …

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Efficient Demultiplexing Of Network Packets By Automatic Parsing, Mahesh Jayaram, Ron K. Cytron Jan 1995

Efficient Demultiplexing Of Network Packets By Automatic Parsing, Mahesh Jayaram, Ron K. Cytron

All Computer Science and Engineering Research

Packet filters are a mechanism for efficiently demultiplexing network packets to application endpoints. There is currently no general, formal specification method for packet filters that allows for easy or efficient composition of specifications. In this paper we present an automatic approach that achieves all of these goals. We approach packet filter specification as a language recognition problem: each filter is represented by a context-free grammar, whose language is the set of packets the filter should accept. Thus, packet filters can be formulated through a general, well defined specification; further, the grammar-based approach simplifies filter composition, which is essential where scalability …

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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.

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Runtime Support For In-Core And Out-Of-Core Data-Parallel Programs, Rajeev Thakur Jan 1995

Runtime Support For In-Core And Out-Of-Core Data-Parallel Programs, Rajeev Thakur

Electrical Engineering and Computer Science - All Scholarship

Distributed memory parallel computers or distributed computer systems are widely recognized as the only cost-effective means of achieving teraflops performance in the near future. However, the fact remains that they are difficult to program and advances in software for these machines have not kept pace with advances in hardware. This thesis addresses several issues in providing runtime support for in-core as well as out-of-core programs on distributed memory parallel computers. This runtime support can be directly used in application programs for greater efficiency, portability and ease of programming. It can also be used together with a compiler to translate programs …

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Real-Time Upcalls: A Mechanism To Provide Real-Time Processing Guarantees, Raman Gopalakrishna, Guru M. Parulkar Jan 1995

Real-Time Upcalls: A Mechanism To Provide Real-Time Processing Guarantees, Raman Gopalakrishna, Guru M. Parulkar

All Computer Science and Engineering Research

Real-time upcalls (RTUs) are an operating systems mechanism that can be used by applications to efficiently schedule code segments (or handlers) that must execute periodically. While the mechanism was conceibed to support protocol processing with quality-of-service guarantees for networked multimedia applicatoins it is general enough to be applicable in other domains like real-time image processing. Until now real-time threads have been the only mechanism for implementing protocols in user space with QoS guarantees. The RTU mechanism avoids the implementation complexity of the thread based approach while retaining its ability to ensure real-time behavior. In addition, our design simplifies protocol code, …

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Production Of Excited Beauty States In Z Decays, D. Buskulic, Manoj Thulasidas Jan 1995

Production Of Excited Beauty States In Z Decays, D. Buskulic, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

A data sample of about 3.0 million hadronic Z decays collected by the ALEPH experiment at LEP in the years 1991 through 1994, is used to make an inclusive selection of B hadron events.

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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 …

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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 …

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Euphoria Reference Manual, T. Paul Mccartney, Kenneth J. Goldman Jan 1995

Euphoria Reference Manual, T. Paul Mccartney, Kenneth J. Goldman

All Computer Science and Engineering Research

No abstract provided.

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Building Interactive Distributed Applications In C++ With The Programmers' Playground, Kenneth J. Goldman, T. Paul Mccartney, Ram Sethuraman, Bala Swaminathan And Todd Rogers Jan 1995

Building Interactive Distributed Applications In C++ With The Programmers' Playground, Kenneth J. Goldman, T. Paul Mccartney, Ram Sethuraman, Bala Swaminathan And Todd Rogers

All Computer Science and Engineering Research

No abstract provided.

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A Single-Stroke Orientation-Orient Gesture System, Yike Hu Jan 1995

A Single-Stroke Orientation-Orient Gesture System, Yike Hu

All Computer Science and Engineering Research

No abstract provided.

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Robust Decentralised Variable Structure Control For Rigid Robotic Manipulators, Thasapalan Kuhan Jan 1995

Robust Decentralised Variable Structure Control For Rigid Robotic Manipulators, Thasapalan Kuhan

Theses : Honours

In this thesis, the problem of robust variable structure control for non-linear rigid robotic manipulators is investigated. Robustness and convergence results are presented for variable structure control systems of robotic manipulators with bounded unknown disturbances, nonlinearities, dynamical couplings and parameter uncertainties. The major outcomes of the work described in this thesis are summarised as given below. The basic variable structure theory is surveyed, and some basic ideas such as sliding mode designs, robustness analysis and control1er design methods for linear or non-linear systems are reviewed. Three recent variable structure control schemes for robotic manipulators are discussed and compared to highlight …

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Adaptive Resonance Associative Map, Ah-Hwee Tan Jan 1995

Adaptive Resonance Associative Map, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

This article introduces a neural architecture termed Adaptive Resonance Associative Map (ARAM) that extends unsupervised Adaptive Resonance Theory (ART) systems for rapid, yet stable, heteroassociative learning. ARAM can be visualized as two overlapping ART networks sharing a single category field. Although ARAM is simpler in architecture than another class of supervised ART models known as ARTMAP, it produces classification performance equivalent to that of ARTMAP. As ARAM network structure and operations are symmetrical, associative recall can be performed in both directions. With maximal vigilance settings, ARAM encodes pattern pairs explicitly as cognitive chunks and thus guarantees perfect storage and recall …

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