This report includes information concerning experimental use of unregistered pesticides or unregistered uses of pesticides. Experimental results should not be interpreted as recommendations for use. Use of unregistered materials or use of any registered pesticides inconsistent with its label is against both Federal Law and State Law.
This report includes information concerning experimental use of unregistered pesticides or unregistered uses of pesticides. Experimental results should not be interpreted as recommendations for use. Use of unregistered materials or use of any registered pesticides inconsistent with its label is against both Federal Law and State Law.
This report includes information concerning experimental use of unregistered pesticides or unregistered uses of pesticides. Experimental results should not be interpreted as recommendations for use. Use of unregistered materials or use of any registered pesticides inconsistent with its label is against both Federal Law and State Law.
This report includes information concerning experimental use of unregistered pesticides or unregistered uses of pesticides. Experimental results should not be interpreted as recommendations for use. Use of unregistered materials or use of any registered pesticides inconsistent with its label is against both Federal Law and State Law.
This report includes information concerning experimental use of unregistered pesticides or unregistered uses of pesticides. Experimental results should not be interpreted as recommendations for use. Use of unregistered materials or use of any registered pesticides inconsistent with its label is against both Federal Law and State Law.
This report includes information concerning experimental use of unregistered pesticides or unregistered uses of pesticides. Experimental results should not be interpreted as recommendations for use. Use of unregistered materials or use of any registered pesticides inconsistent with its label is against both Federal Law and State Law.
This report includes information concerning experimental use of unregistered pesticides or unregistered uses of pesticides. Experimental results should not be interpreted as recommendations for use. Use of unregistered materials or use of any registered pesticides inconsistent with its label is against both Federal Law and State Law.
This report includes information concerning experimental use of unregistered pesticides or unregistered uses of pesticides. Experimental results should not be interpreted as recommendations for use. Use of unregistered materials or use of any registered pesticides inconsistent with its label is against both Federal Law and State Law.
This report includes information concerning experimental use of unregistered pesticides or unregistered uses of pesticides. Experimental results should not be interpreted as recommendations for use. Use of unregistered materials or use of any registered pesticides inconsistent with its label is against both Federal Law and State Law.
This report includes information concerning experimental use of unregistered pesticides or unregistered uses of pesticides. Experimental results should not be interpreted as recommendations for use. Use of unregistered materials or use of any registered pesticides inconsistent with its label is against both Federal Law and State Law.
This paper describes a real time garbage collection algorithm. It allocates storage automatically from a heap, and does not require the programmer to give any indication that particular items are no longer useful or accessible. A garbage collection algorithm is considered to be real time if the amount of work...
University Honors Program Senior Project.
Many times the study of the behavior of an algorithm can be inhibited by the inability to actually see exactly what the algorithm does. Static diagrams and verbal descriptions are often not enough to provide real insight into the behavior of an algorithm. It would...
We present an extended mapping in the Hybrid Uncertainty Manager so that all the components of an influence diagram can be represented. This will allow us to perform decision analysis on a decision problem. Specifically, a representation for decision nodes, value node, and informational arcs will be given. With these...
The Large-Grain Data-Flow (LGDF) Machine is a tightly-coupled multi-processor consisting of several independent nodes, upon each of which may run one or more tasks. These tasks must be able to communicate and synchronize with each other. This document describes a message-passing system developed to meet these requirements.
The message-passing system...
This paper describes the design and implementation of a graphical user interface for construction and evaluation of influence diagrams. Specifically, this paper documents the representation, display and mouse sensitivity of an influence diagram, and the selection facility subsystem. The interface is designed to communicate with the user by a mouse...
This document describes the need for, and design of, diagnostic software that provides circuit verification, fault isolation, and troubleshooting aids. The difference between verification software and true diagnostic software is explained. A modular design of diagnostic software is proposed, consisting of a series of 3-part tests, a test manager, results...
The Sacagawea testbed has been designed to support testing and development of decision making models, and associated uncertainty management techniques, that are appropriate under real-time problem solving constraints. Conceptually, it provides a simulated temporal and spatial environment, the latter consisting of a terrain grid of elevation and tree cover data,...
This report describes "VIGRAM" (Visual Programming) which is a program understanding and complexity metric analysis tool for Pascal programs. VIGRAM is implemented on the Macintosh as one part of the "O.S.U." (Qregon Speedcode Universe) project. With VIGRAM, the source code of a Pascal procedure can be displayed as a visual...
Performance of a reliable storage subsystem for a centralized database system was studied by simulation. The reliable storage subsystem studied consists of three redundant disk units that are updated one at a time from a consistent database state to another consistent database state, Thus, even if a central processor and/or...
This survey looks at five different polygon breaking algorithms and compares them. The criteria for comparison are:
1. Complexity of the algorithm.
2. The number and type of subpolygons produced.
3. The classes of input polygons that can be broken.
The best algorithm is then coded and a comparison is...
This paper presents the initial results from an empirical study of mechanical design engineers. In this study, six engineers were video-taped solving real mechanical design problems. Preliminary analysis of this protocol data has yielded several important findings, including (a) mechanical designers progress from systematic to opportunistic behavior as the design...
Acoustic position estimation is used where high accuracy navigation is required over a small area, such as for searching or for collecting gravitational or geomagnetic data. In this position estimation method, a surface ship or submersible periodically sends out a high-frequency acoustic 'ping' at a prearranged frequency. This ping is...
System architectures for interconnecting large numbers of processors are being widely studied [AG82,TH75,TR82]. Of particular interest in such architectures is the exploitation of concurrency among processors. This concurrency can be parallelism, in which different parts of a single data case are processed at the same time, or pipelining, in which...
This grant supported acquisition of a minicomputer system for departmental research. The equipment selected is a DEC VAX-11/750 system, installed in remodeled space in the Computer Science (formerly Farm Crops) Building. Grant funds for equipment acquisition were supplemented by support from the Tektronix Foundation.
After completion of the physical facilities...
Advanced computer architectures are centered around the parallel computer systems. This project is focused on the experiment on two parallel computer architectures : Sequent Balance 21000 shared memory multiprocessor and Cogent XTM distributed system.
A set of benchmark programs are implemented using "C" language and Dynix parallel programming library on...
Three different approaches to type checking have been taken in object-oriented programming languages. Smalltalk-80 uses run-time type checking. C++ uses subtypes. A third alternative is to use parameterized types. We examine the difficulties of programming in an object-oriented fashion with compile-time type checking and argue that parameterized types are better...
Recent advances in diagnostic expert systems have been limited by the crucial Knowledge Acquisition Problem: to bring expert heuristics into logical, conditional rule forms useful for computer aided diagnosis. Some automatic systems with potential biomedical relevance that do acquire knowledge are reviewed here, and analyzed from the standpoint of possible...
Exploratory Data Analysis (EDA) is a lesser known field which has outgrown the bounds of statistics. It differs from ordinary, or “confirmatory”, data analysis. Originated by John Tukey, EDA aspires toward an open-ended meta-goal: to discover “all interesting” [nontrivial, normal form, valid] hypotheses about a domain that is represented by...
There is disagreement about the role and importance of typographic style (source code formatting and commenting) in program comprehension. Results from experiments and opinions in programming style books are mixed.
This paper presents principles of typographic style consistent and compatible with the results of program comprehension studies. It introduces the...
This paper presents the results of a controlled experiment comparing debugging abilities of novice, intermediate and skilled student programmers. Debugging performance differences were studied using two single-page Pascal programs: a binary search program and a median calculation program. Two types of semantic errors, array bounds and undefined variable, and two...
A database to be used by electrical circuit design, test, and repair expert systems must support both structural data and inferential data about the circuit. It is well known that engineering databases must support dynamic schema (re)definition of the structural data and entity-based access to it. We analyze this requirement...
X2 is an object-oriented programming language. Object-oriented programming models everything in the world as objects that have some local state that may vary with time. If the state of an object varies with time the object is mutable. If the state is time independent the object is immutable. Each object's...
Many studies have shown that expert programmers are more effective at debugging programs than novice programmers. These studies have suggested that the major reason for this difference is due to the experts' superior comprehension of the program. This paper reports two experiments which investigated expert and novice student programmers program...
FORTRAN permits both explicit and implicit options for both data declaration and type conversion features. This study investigated the effects of explicit and implicit data declaration and type conversion features on a program comprehension task performed by FORTRAN programmers in an introductory programming course. The results indicated that both factors...
This study examined the UNIX command abbreviation schemes preferred by expert and novice UNIX programmers. The two parts of the conducted experiment were: subjective rating of UNIX command abbreviations for each of the six abbreviation categories (acronym, combination, contraction, identity, synonym, and truncation); subjects suggested descriptive command names for UNDC...
A theory for resiliency control of distributed database systems is developed, and schemes that preserve the consistent global database state in the presence of site crashes and message link failures are discussed. The schemes can at least theoretically be paired with any concurrency control scheme that produces y-serializable executions. Further,...
It is highly desirable for a distributed database system to achieve logically continuous operation even if some sites or message links fail. In this paper, we describe a scheme that can automatically reconfigure a fully-replicated distributed database system upon subsystem failures. The scheme can tolerate total failures of some sites....
A typical database system maintains target data, which contain information useful for users, and access path data, which facilitate faster accesses to target data. Further, most large database systems support concurrent processing of multiple transactions. For a static database system model, where units of concurrency control are not dynamically created...
In this short paper, we present an implementation method for a distributed commit/ termination protocol for a distributed database system. The protocol, which handles both commit and termination processing of distributed transactions, is represented by communicating Moore machines. Several advantages of our approach are discussed.
A concurrency and resiliency control scheme for a distributed database system with replicated data is discussed. The scheme, true-copy token scheme, uses true-copy tokens in order to designate the physical data copies (true copies) that can be identified with the current logical data that are globally unique, and then it...
This technical report reprints two articles that appeared in Proceedings of the Third International Machine Learning Workshop at Skytop, Pennsylvania, June 24-26, 1985. The first paper, The EG Project: Recent Progress, summarizes work on the EG project, which is investigating the role of active experimentation in aiding machine learning programs....
The "style metric" of Berry and Meekings is purported to quantify the lucidity of software written in the C programming language. We used a modification of this metric to try and identify error-prone software. Our results indicate that this metric seems to bear little relationship to the density of errors...
This tutorial discusses one of the oldest problems in computing: how to search and retrieve keyed information from a list in the least amount of time. Hashing - a technique that mathematically converts a key into a storage address - is one of the best methods of finding and retrieving...
Tbc expanding complexity of database application worlds, and the accelerating pace of change of these worlds mandate data models which support some of the tasks of data interpretation which formerly were borne by the applications programs. Chief among these are the support for virtual data, definition of transactions, and enforcement...
ELGDF (Extended Large Grain Data Flow) is a design language that allows representation of a wide variety of parallel programs. The syntax is graphical and hierarchical to allow construction and viewing of realistically sized programs. ELGDF language facilitates describing parallel programs in a natural way for both shared memory model...
New parallel algorithms for solving the decomposed linear programs are developed. Direct parallelization of the sequential algorithm results in very limited performance improvement using multiple processors. By redesigning the algorithm, we achieved more than 2*P times performance improvement over the sequential algorithm, where P is the number of processors used...