Physical Sciences and Mathematics Commons^™

Parametricity And Local Variables, Peter W. O'Hearn, R. D. Tennent

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

We propose that the phenomenon of local state may be understood in terms of Strachey 's concept of parametric (i.e., uniform) polymorphism. The intuitive basis for our proposal is the following analogy: a non-local procedure is independent of locally-declared variables in the same way that a parametrically polymorphic function is independent of types to which it is instantiated. A connection between parametricity and representational abstraction was first suggested by J. C. Reynolds. Reynolds used logical relations to formalize this connection in languages with type variables and user-defined types. We use relational parametricity to construct a model for an Algol-like language …

Note On Algol And Conservatively Extending Functional Programming, Peter W. O'Hearn

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

A simple Idealized Algol is considered, based on Reynolds's "essence of Algol." It is shown that observational equivalence in this language conservatively extends observational equivalence in its assignment-free functional sublanguage.

Irregular Personalized Communication On Distributed Memory Machines, Sanjay Ranka, Jhy-Chun Wang

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

In this paper we present several algorithms for performing all-to-many personalized communication on distributed memory parallel machines. We assume that each processor sends a different message (of potentially different size) to a subset of all the processors involved in the collective communication. The algorithms are based on decomposing the communication matrix into a set of partial permutations. We study the effectiveness of our algorithms both from the view of static scheduling and from runtime scheduling.

Run-Time Support For Parallelization Of Data-Parallel Applications On Adaptive And Nonuniform Computational Environments, Maher Kaddoura, Sanjay Ranka

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

In this paper we discuss the runtime support required for the parallelization of unstructured data parallel applications on nonuniform and adaptive environments. The approach presented is reasonably general and is applicable to a wide variety of regular as well as irregular applications. We present performance results for the solution of an unstructured mesh on a cluster of heterogeneous workstations.

The Expressiveness Of Locally Stratified Programs, Howard A. Blair, Wiktor Marek, John S. Schlipf

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

This paper completes an investigation of the logical expressibility of finite, locally stratified, general logic programs. We show that every hyperarithmetic set can be defined by a suitably chosen locally stratified logic program (as a set of values of a predicate over its perfect model). This is an optimal result, since the perfect model of a locally stratified program is itself an implicitly definable hyperarithmetic set (under a recursive coding of the Herbrand base); hence to obtain all hyperarithmetic sets requires something new, in this case selecting one predicate from the model. We find that the expressive power of programs …

Communication-Efficient And Memory-Bounded External Redistribution, Jang Sun Lee, Sanjay Ranka, Ravi V. Shankar

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

This paper presents communication-efficient algorithms for the external data redistribution problem. Deterministic lower bounds and upper bounds are presented for the number of I/O operations, communication time and the memory requirements of external redistribution. Our algorithms differ from most other algorithms presented for out-of-core applications in that it is optimal (within a small constant factor) not only in the number of I/O operations, but also in the time taken for communication. A coarse-grained MIMD architecture with I/O subsystems attached to each processor is assumed, but the results are expected to be applicable over a wider variety of architectures.

Mapping Unstructured Computational Graphs For Adaptive And Nonuniform Computational Environments, Maher Kaddoura, Chao Wei Ou, Sanjay Ranka

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

In this paper we study the problem of mapping a large class of irregular and loosely synchronous data-parallel applications in a nonuniform and adaptive computational environment. The computational structure of these applications can be described in terms of a computational graph, where nodes of the graph represent computational tasks and edges describe the communication between tasks. Parallelization of these applications on nonuniform computational environments requires partitioning the graph among the processors in such fashion that the computation load on each node is proportional to its computational power, while communication is minimized. We discuss the applicability of current methods for graph …

Optimization Using Replicators, Anil Ravindran Menon, Kishan Mehrotra, Chilukuri K. Mohan, Sanjay Ranka

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

Replicator systems are among the simplest complex systems and can be considered to be at the foundation of many popularly used models ranging from theories of evolution and neurobiology to sociobiology and ecology. This paper presents the first successful application 2 of replicators to optimization problems. For a graph bi-partitioning problem with 50,000 nodes and 300,000 edges, for instance, close to optimal solutions were obtained in a few hundred iterations. Replicators provide a potentially powerful new tool to solve other optimization problems as well.

Passion Runtime Library For The Intel Paragon, Alok Choudhary, Rajesh Bordawekar, Sachin More, K. Sivaram, Rajeev Thakur

Electrical Engineering and Computer Science - All Scholarship

We are developing a runtime library which provides a number of routines to perform the I/O required in parallel applications in an efficient and convenient manner. This is part of a project called PASSION, which aims to provide software support for high-performance parallel I/O at the compiler, runtime and file system levels. The PASSION Runtime Library uses a high-level interface which makes it easy for the user to specify the I/O required in the program. The user only needs to specify what portion of the data structure needs to read from or written to the file, and the PASSION routines …

A Simulation Model Of A Surveillance Radar Data Processing System Using Hi-Mass, Steven D. Farr, Alex F. Sisti, Douglas G. Fritz, Robert G. Sargent

Electrical Engineering and Computer Science - All Scholarship

This paper discusses the model specification, construction of the executable model, model execution, and the simulation results of a simulation model of a surveillance radar data processing system that was developed using the Hierarchical Modeling and Simulation System (HI-MASS). HI-MASS is an object oriented C++ based system that supports model specification (modeling) using the Hierarchical Control Flow Graph Model paradigm and executes simulation models using the sequential synchronous simulation execution algorithm. Models specified in this model paradigm use two complementary hierarchical specification structures, one to specify the model components and their interconnections and the other to specify the behaviors of …

An Evaluation Of Design Tradeoffs In A High Performance Media-On-Demand Server, Divyesh Jadav, Chutimet Srinilta, Alok Choudhary, P. B. Berra

Electrical Engineering and Computer Science - All Scholarship

One of the key components of a multi-user multimedia-on-demand system is the data server. Digitalization of traditionally analog data such as video and audio, and the feasibility of obtaining network bandwidths above the gigabit-per-second range are two important advances that have made possible the realization, in the near future, of interactive distributed multimedia systems. Secondary-to-main memory I/O technology has not kept pace with advances in networking, main memory and CPU processing power. Consequently, the performance of the server has a direct bearing on the overall performance of such a system. In this paper we present a high-performance solution to the …

National Hpcc Software Exchange, Shirley Browne, Jack Dongarra, Stan Green, Keith Moore, Tom Rowan, Reed Wade, Geoffrey .. Fox, Ken Hawick

Electrical Engineering and Computer Science - All Scholarship

This report describes an effort to construct a National HPCC Software Exchange (NHSE). This system shows how the evolving National Information Infrastructure (NII) can be used to facilitate sharing of software and information among members of the High Performance Computing and Communications (HPCC) community. To access the system use the URL: http://www.netlib.org/nse/.

Verification And Validation Of Simulation Models, Douglas G. Fritz, Robert G. Sargent, Thorsten Daum

Electrical Engineering and Computer Science - All Scholarship

The Hierarchical Modeling and Simulation System (HI-MASS) is a prototype modeling and simulation system that supports modeling based on the Hierarchical Control Flow Graph Model paradigm and simulation execution using a sequential synchronous simulation algorithm. The prototype is an object oriented C++ based system designed for a Unix environment and implemented using freely available software tools. Models are specified using two complementary hierarchical model specification structures, one to specify the components which comprise a model and how those components are interconnected, and the other to specify the behaviors of the individual components. A graphical user interface provides for component and …

Effects Of Technology Mapping On Fault Detection Coverage In Reprogrammable Fpgas, Kevin A. Kwiat, Warren Debany, Salim Hariri

Electrical Engineering and Computer Science - All Scholarship

Although Field-Programmable Gate Arrays (FPGAs) are tested by their manufacturers prior to shipment, they are still susceptible to failures in the field. In this paper, test vectors generated for the emulated (i.e., mission) circuit are fault simulated on two different models: the original view of the circuit, and the design as it is mapped to the FPGA's logic cells. Faults in the cells and in the programming logic are considered. Experiments show that this commonly-used approach fails to detect most of the faults in the FPGA.

Dartcvl: The Dartmouth C Vector Library, Thomas H. Cormen, Sumit Chawla, Preston Crow, Melissa Hirschl, Roberto Hoyle, Keith D. Kotay, Rolf H. Nelson, Nils Nieuwejaar, Scott M. Silver, Michael B. Taylor, Rajiv Wickremesinghe

Computer Science Technical Reports

As a class project, we implemented a version of CVL, the C Vector Library, on a DECmpp 12000/Sx 2000, which is equivalent to the MasPar MP-2 massively parallel computer. We compare our implementation, DartCVL, to the University of North Carolina implementation, UnCvl.

DartCVL was designed for the MP-2 architecture and UnCvl was designed for the MP-1. Because the MasPar MP-1 and MP-2 are functionally equivalent, both DartCVL and UnCvl will run on either. Differences in the designs of the two machines, however, may lead to different software design decisions. DartCVL differs from UnCvl in two key ways. First, DartCVL uses …

Critical Success Factors For Organizational Case Success, Chad Strauss

Presidential Scholars Theses (1990 – 2006)

Practitioners and researchers have suggested that Computer Aided Software Engineering (CASE) technology can significantly improve the productivity of systems analysts and the quality of systems development. Before CASE can succeed, however, specific components must exist. This paper explores CASE and the components necessary for its widespread acceptance and use within information systems departments. Specifically, this paper will examine the systems development life cycle (SDLC), the possible benefits of CASE, the current state of CASE, critical success factors for CASE, and finally CASE use.

Transient Data Sharing Among Mobile Programs, Jerome Plun, Gruia-Catalin Roman

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 present designers with unprecedented challenges in the areas of modularity and dependability. This paper describes a modular approach to specifying and reasoning about of mobile computing. Its novelty rests with the notion of allowing transient (location-dependent) data sharing among programs which move in space. The notation is a direct extension of that used in UNITY and reasoning about …

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 …

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.

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 …

Reliable Stream Transmission In Mobile Computing Environments, Houzhi Xu, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.

Brokered Collaborative Infrastructure For Cscw, Chandrajit Bajaj, Peinan Zhang, Alok R. Chaturvedi

Department of Computer Science Technical Reports

No abstract provided.

Decimation Of 2d Scalar Data With Error Control, Daniel R. Schikore, Chandrajit L. Bajaj

Department of Computer Science Technical Reports

No abstract provided.

Finiteness Of The Fixed Point Set For The Simple Genetic Algorithm, Alden H. Wright, Michael D. Vose

Computer Science Faculty Publications

The infinite population simple genetic algorithm is a discrete dynamical system model of a genetic algorithm. It is conjectured that trajectories in the model always converge to fixed points. This paper shows that an arbitrarily small perturbation of the fitness will result in a model with a finite number of fixed points. Moreover, every sufficiently small perturbation of fimess preserves the finiteness of the fixed point set. These results allow proofs and constructions that require finiteness of the fixed point set. For example, applying the stable manifold theorem to a fixed point requires the hyperbolicity of the differential of the …

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 …

Biometric Imaging: Three Dimensional Imaging Of The Human Hand Using Coded Structured Lighting, T. A. Vuori, C. L. Smith

Research outputs pre 2011

In this report the results of applying a three dimensional range imaging system, based on coded structured light, are presented. This includes a description of a new improved spatial coding scheme. This new scheme increases the number of reference points available and provides a basis for more accurate calculation of their location. A detailed description of the image processing methods used to extract structural information and to identify structural objects from the camera image are given. In addition the method used to calculate the locations of reference points with 'subpixel' accuracy is described. Finally, the results of experiments with synthesised …

An Ada-Like Language To Facilitate Reliable Coding Of Low Cost Embedded Systems, Michael Collins

Theses : Honours

Due to a lack of operating system (0/S) support, it is more difficult to develop programs for embedded systems than for workstations. For those developing on a low budget, the problem is often further compounded by the necessity of using inappropriate, 0/S dependent, compilers. This study attempts to ascertain those elements of a High Level Language (HLL) which are absolutely necessary and implementable to produce reliable, efficient, embedded programs without the benefit of a large budget. The study is based upon the Ada philosophy as the Ada language incorporates many desirable features for modelling real-world problems in terms of embedded …

Maintaining High Throughput During Overload In Atm Switches, Jonathan S. Turner

All Computer Science and Engineering Research

This report analyzes two popular heuristics for ensuring packet integrity in ATM switching systems. In particular, we analyze the behavior of packet tail discarding, in order to understand how the packet level link efficiency is dependent on the rates of individual virtual circuits and the degre of the imposed overload. In addition, we study early packet discard and show that the queue capacity needed to achieve high efficiency under worst-case conditions grows with the number of virtual circuits and we determine the efficiency obtainable with more limited queue capacities. Using the insights from these analyses, extensions to early packet discard …

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, …

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

All Computer Science and Engineering Research

No abstract provided.