Cryptographic systems are used for secure communications in the government, in industry, and by individuals. Many cryptographic systems base their security on our inability to factor quickly. For this reason, in the last few decades several fast factoring algorithms have been developed. The Quadratic Sieve is one of the best...
We define simple population models and give seven examples from the literature. We investigate visualization techniques for simple population models and demonstrate these techniques on the seven population models. The visualization techniques are basic curves, spiral plots, time plots, bifurcation maps, time-plus-2 curves, and B&W and color complex convergence plots....
Suffix trees are a well known data structure for facilitating a variety of queries on strings. Construction of the trees requires a considerable number of choices concerning the implementation. Several of those choices are examined in this paper. Performance studies are presented that reveal the consequences of these choices. The...
We describe a software mechanism that simplifies the implementation of real-time distributed object-oriented applications. The distributed observable/observer mechanism extends the Observable/Observer concept of Java to a distributed environment, encapsulating the communication protocol used by networking. The mechanism supports the distributed model/view-controller (M/VC) paradigm, allowing view-controllers to be attached to remote...
Structural active-object systems (SAOSs) are transition-based object-oriented systems suitable for various concurrent applications. A SAOS consists of a collection of interacting active objects that can be structurally and hierarchically composed. The SAOS framework enables $AO$ application programs to be developed rapidly. However, nondeterministic behaviors of active object sometimes make debugging...
MIDAS is an application framework for remote data acquisition and visualization that allows dynamic reconfiguration of its constituent components. There are three types of reconfiguration, namely, component replacement, component interposition and component deletion. A two-phase protocol to maintain the consistency of the system during reconfiguration is described. MIDAS has a...
With the strong shift toward network-centric cluster-computing workload management has become increasingly important in both industrial and academic environments. To fully harness the distributed computing resources of the 32 PC's in our department, I developed a workload monitoring system together with a few utilities for users to submit either sequential...
The purpose of this project is to study the benefit at large parking lots having shuttle busses by providing a system that dynamically routes a shuttle. The shuttle route will be set by the placement of the travelers returning from the terminal. A parking space is assigned to the incoming...
The problem addressed in this paper is that of usability of the Petri Net Editor used to create applications in the Objex framework. This editor puts a lot of burden on the user, in that the user needs to remember all the GUI resources previously created for the application, has...
A structural active-object systems (SAOS) is a, transition-based object-oriented system consisting of a collection of interacting structural active objects (SAOs), which can be structurally and hierarchically composed from their component SAOs. The behaviors of SAOs are determined by the transition statements provided in their class definitions. Various concurrent systems such...
Since its introduction in 1995 by Sun Microsystems, the Java programming language has been widely accepted by the software development community. Besides being a natural fit for Internet and World Wide Web (WWW) based applications, Java is also being used in other diverse application areas due to its simplicity, reduced...
Structural active-object systems (SAOSs) are transition-based object-oriented systems suitable as frameworks of various concurrent systems. AOSs are constructed from their component active objects by structural and hierarchical object composition (SHOC) like hardware systems. 1n this report, we demonstrate that the SAOS approach is effective in implementing a graphical editor. The...
To achieve the maximum benefits of a flexible manufacturing system (FMS), its effective monitoring is crucial. The user's ability to interpret the actions of an FMS is significantly enhanced by effective monitoring provided by a well-designed graphical user interface (GUI). The Active-Object User-Interface Management System (AOUIMS) is a graphical user...
A structural active-object system (SAOS) is a transition-based object-oriented system suitable for the design of various concurrent systems. A SAOS consists of a collection of interacting structural active objects (SAOs) whose behaviors are determined by the transition statements provided in their class definitions. Furthermore, SAOs can be structurally and hierarchically...
The integration of Asynchronous Transfer Mode (ATM) technology into the current global internetwork provides great opportunity as weJl as substantial engineering challenges. The Network for Engineering Research in Oregon (NERO) ATM network provides an order of magnitude increase in available bandwidth in local area networks and two orders of magnitude...
Qualitative reasoning programs use a modelling language to discover the function of a mechanical device and a theory of causality to explain the reason for the device's behavior. A library of reusable model pieces for linear mechanical oscillators was developed for use with a causality theory developed by Forbus called...
The problem of broadcasting in faulty hypercubes is considered, based upon a strategy of partitioning the faulty hypercube into subcubes in which currently known algorithms can be implemented. Three similar partitioning and broadcasting algorithms for an n-dimensional hypercube in the presence of up to (n² + 2n - c) /...
In order for autonomous underwater vehicles to be successful, they must be able to maintain accurate information about their state variables and the state of their critical components. The software developed by Bruce D'Ambrosia and Wade Brittain, (Real-time Tracking and Probabilistic Assessment of Physical Systems) proposes a methodology to provide...
In order for long-range autonomous robots to be successful they must be able to maintain accurate information about their location, available resources, and the state of critical components. We propose here a methodology which incorporates traditional, sensor-based tracking methods with discrete probabilistic representations of system state. Further, we extend the...
Code instrumenters play a vital role in the functionality of the Aristotle program analysis system, This project aims to replace Aristotle's existing code instrumenters, which process target programs at the, source level, with instrumenters that process target programs at the intermediate language level. This change absolves the instrumenters of responsibility...
Existing graphics systems are too large for students to study in an introductory computer graphics course. We have implemented a lightweight, object-oriented graphics system called OGS for instruction. OGS is written in Java. It demonstrates how a graphics system is implemented from scratch and is intended to help students understand...
In this paper, we describe a software mechanism, a software channel, that allows a group of distributed objects to communicate with each other automatically once they are connected to it. Software channels and predesigned distributed objects that are connected to them encapsulate the communication protocol and the network topology to...
A Kalman filter was developed to recover information on short period variations of ocean circulation from the satellite altimeter signals for the North Pacific Ocean. The ocean circulation at each grid point is specified by three variables: sea level height h, zonal velocity u, and meridional velocity v. In our...
This project is an interactive environment which allows the user to explore various sound generation techniques. The three methods of sound generation used are (1) FM synthesis, (2) Additive synthesis, and (3) Karplus/Strong synthesis of plucked strings. The project also provides the capability to display the generated sound waveforms and...
The SAOS Road Network Simulator (SARNS) is a graphical simulation program for transportation planning, implemented using the structural active-object system (SAOS) approach. A SAOS is an object-oriented concurrent system that consists of a collection of interacting structural active objects (SAOs), whose behaviors are determined by transition statements provided in their...
The project (partially) described in this paper was the result of an attempt by the Navy to use software complexity metrics to assess the complexity of Naval avionics software. In particular, the project consisted of computing a variety of software complexity metrics for CMS-2M and AYK-14 assembler source code and...
Visualization is a useful method to teach classes in algorithms and data structures. Many animation systems of algorithms and data structures have been implemented. In these systems, students can set initial conditions, run algorithms and view the result graphically. In this project, a small visualization tool library is implemented using...
In this paper, we present two systolic designs of a chip that can be used to perform Modular Multiplication. The time taken by these two designs is 5n and 3n respectively, where n is the number of digits. These designs are based on Montgomery's redc algorithm. We also present an...
Exception handling is a general purpose tool found in many modern programming language, but most work to date is based on textual languages. We present an approach to exception handling in a new context, the visual programming language Forms/3. The visual nature of Forms/3 supports an effective approach to exception...
A problem with a number of available parallel programming tools proposed and implemented by researchers is that there has been little consideration of the impact of the user interface on users outside the field of computer science.
In this paper we propose and implement Banger, an extension to the Parallel...
We believe concreteness, direct manipulation and responsiveness in a visual programming language increase its usefulness. However, these characteristics present a challenge in generalizing programs for reuse, especially when concrete examples are used as one way of achieving concreteness. In this paper, we present a technique to solve this problem by...
I present a new heuristic search approach to compute approximate answers for the probability query in belief nets. This approach can compute the 'best' bounds for a query in a period of any given time (if time permitted, it will get an exact value). It inherits the essence of Symbolic...
This PNW Extension publication provides an overview of various types of powderpost beetles, the symptoms associated with their damage, as well as tips for prevention and control.
Forms are the most common means of interacting with databases. Database develop1;11ent products offer differing capabilities for creating forms. We will compare the form design features available using 4th Dimension and Oracle database products. These two products have the most complete set of features compared to other micro computer database...
This volume contains the papers accepted for the informal workshop on Knowledge Compilation and Speedup Learning held along with the Machine Learning Conference in Aberdeen Scotland. This workshop is a sequel to the first Knowledge Compilation workshop, which was organized by Jim Bennett, Tom Dieterich, and Jack Mostow in Otter...
Until now, most hypertext systems have been implemented on large scale computers. With improvements in microprocessors and development of graphical user interfaces, personal computers can run systems that previously needed the power of a mainframe. The low costs and widespread use of PCs will enable many people to use hypertext...
This report addresses the design and implementation of an internet-based grading tool for the "Translators" course. The motivation is to avoid exposing the instructor's Java byte-code to possible reverse-engineering tools and enable students to submit their homework virtually from any machine across the internet. This tool is intended to replace...
This document defines the language Leda as currently implemented by the authors and Vinoo Cherian. Leda is an evolving research language and readers may wish to consult the bibliography for a variety of papers concerning its raison d'être. Our purpose here is to guide investigators in the use of a...
In this project we have designed a new construction method for t error correcting constant weight codes. This method is an improvement over the existing codes in terms of information rate. The construction method is recursive as it is based on the observation that 2t error correcting code can be...
Visualizing and navigating through a plan is difficult without graphics. Two X applications, PlanView and HViews, are graphical user interfaces to an AI planner, OPIE, developed at the University of Oregon. In addition to a plan generator, OPIE includes a facility to generate operator abstractions which in turn are used...
This paper describes the results of a research project to design new graphical user interlace to an existing applications software product, using the techniques of user-centered design. The project began with a literature review to determine the currently accepted methodology in the area of user-centered design, with emphasis on the...
To be competitive in the development and production of complex electronic systems, a company must constantly scrutinize its manufacturing processes to find ways to reduce costs and increase productivity. One of the more costly problems is the inability to troubleshoot and repair faulty circuit boards on the spot. Rather, they...
Preparing code for parallelization is one of the most time consuming programming tasks; approximately 24% of the program development activity is spend in this phase. In message passing systems, this is usually achieved by the addition of run-time message-passing library calls. The primitives provided by different message-passing libraries are similar,...
One of the main problems in debugging parallel programs is in determining how far a parallel program has executed when it crashes or stops. Even if the program dumps core files for all the parallel processes, the information is at such a low level that it is difficult to interpret...
Development of graphical user interface (GUI) applications is difficult since the process can be both complicated and tedious. We propose a solution directed at reducing programming time and effort required to build a GUI application. Our solution is based on the Petri Network, the Oregon SpeedCode Universe (OSU) Application Framework,...
Two types of parallel computers commonly used or solving large scientific problems are clusters of workstations and distributed-memory multicomputers. Each system has strengths and weaknesses for this task. Workstation clusters have a high performance to cost ratio and the advantage of the latest processors. Workstations are commonly under-utilized and can...
The processor allocation in an n-dimensional hypercube multiprocessor using buddy strategy, gray code strategy, and a new strategy is implemented on Macintosh. Our implementations show that when processor relinquishment is not considered (i.e. static allocation), all these strategies are optimal in the sense that each incoming request sequence is always...
Objex is an object-oriented framework for producing C++ applications through specialization of a class library and interaction model. The problem addressed in this report is that of automatically producing C++ source code from Petri Network design descriptions of applications constructed from Objex components.
The approach is to add a code...
This study describes the software metrics analysis of IO releases of an embedded real-time telephone switching system developed by a German telecommunications firm. The micro-controlled application was written in a C-like macro assembly language. We developed a metrics program that computes the standard complexity metrics plus a number of information...