David W. Flater

Information Technology Measurement and Testing Activities at NIST

Our high technology society continues to rely more and more upon sophisticated measurements, technical standards, and associated testing activities. This was true for the industrial society of the 20th century and remains true for the information society of the 21st century. Over the last half of the 20th century, information technology (IT) has been a powerful agent of change in almost every sector of the economy. The complexity and rapidly changing nature of IT have presented unique technical challenges to the National Institute of Standards and Technology (NIST) and to the scientific measurement community in developing a sound measurement and testing infrastructure for IT. This measurement and testing infrastructure for the important non-physical and non-chemical properties associated with complex IT systems is still in an early stage of development. This paper explains key terms and concepts of IT metrology, briefly reviews the history of the National Bureau of Standards/National Institute of Standards and Technology (NBS/NIST) in the field of IT, and reviews NIST’s current capabilities and work in measurement and testing for IT. It concludes with a look at what is likely to occur in the field of IT over the next ten years and what metrology roles NIST is likely to play.

A Logical Model of Conceptual Integrity in Data Integration

Conceptual integrity is required for the result of data integration to be cohesive and sensible. Compromised conceptual integrity results in “semantic faults,” which are commonly blamed for latent integration bugs. A logical model of conceptual integrity in data integration and a simple example application are presented. Unlike constructive models that attempt to prevent semantic faults, this model allows both correct and incorrect integrations to be described. Imperfect legacy systems can therefore be modeled, allowing a more formal analysis of their flaws and the possible remedies.

Design of a flexible, integrated testing system for STEP and OMG standards

Abstract New software standards supporting integration of manufacturing and engineering systems are emerging at a rapid pace. Two groups, the Object Management Group (OMG) and the community producing the Standard for the Exchange of Product Model Data (STEP, formally known as ISO 10303), dominate in the production of standards for manufacturing and engineering industries. Their standards are based on common methods, which can be exploited in developing tests for systems supporting the standards. This paper describes the methods employed and a system that builds on those methods to support the automatic and rapid development of conformance tests for the emerging standards.

Manufacturer's CORBA Interface Testing Toolkit: Overview

The Manufacturer’s CORBA Interface Testing Toolkit (MCITT) is a software package that supports testing of CORBA components and interfaces. It simplifies the testing of complex distributed systems by producing “dummy components” from Interface Testing Language and Component Interaction Specifications and by automating some error-prone programming tasks. It also provides special commands to support conformance, performance, and stress testing.

ALIBI: a novel approach to resource discovery

Provides a new answer to the resource discovery problem, which arises because although the Internet makes it possible for users to retrieve enormous amounts of information, it provides insufficient support for locating the specific information that is needed. ALIBI (Adaptive Location of Internetworked Bases of Information) is a new tool that succeeds in locating information without the use of centralized resource catalogs, navigation, or costly searching. Its powerful query‐based interface eliminates the need for the user to connect to one network site after another to find information or to wrestle with overloaded centralized catalogs and archives. This functionality was made possible by an assortment of significant new algorithms and techniques, including classification‐based query routing, fully distributed cooperative caching, and a query language that combines the practicality of Boolean logic with the expressive power of text retrieval. The resulting information system is capable of providing fully automatic resource discovery and retrieval access to a limitless variety of information bases.

A Case Study of Performance Degradation Attributable to Run-Time Bounds Checks on C++ Vector Access.

Programmers routinely omit run-time safety checks from applications because they assume that these safety checks would degrade performance. The simplest example is the use of arrays or array-like data structures that do not enforce the constraint that indices must be within bounds. This report documents an attempt to measure the performance penalty incurred by two different implementations of bounds-checking in C and C++ using a simple benchmark and a desktop PC with a modern superscalar CPU. The benchmark consisted of a loop that wrote to array elements in sequential order. With this configuration, relative to the best performance observed for any access method in C or C++, mean degradation of only (0.881 ± 0.009) % was measured for a standard bounds-checking access method in C++. This case study showed the need for further work to develop and refine measurement methods and to perform more comparisons of this type. Comparisons across different use cases, configurations, programming languages, and environments are needed to determine under what circumstances (if any) the performance advantage of unchecked access is actually sufficient to outweigh the negative consequences for security and software quality.

The Inescapable Relativity of Explicitly Represented Knowledge: An FCA Perspective

Knowledge models are supposed to capture knowledge of lasting value in a reusable form. However, reuse of these models is hampered by arbitrary and application-specific constraints; any constraints that conflict with a new application must be altered or removed before the models can be reused. This article explores seven facets of conceptual relativity that would impact the use of Formal Concept Analysis formalisms to represent knowledge, demonstrating that the capture of application-specific constraints is inextricable from the modelling process.

Specifying Interactions in Integrated Manufacturing Systems

Systems of manufacturing software are often constructed by integrating pre- existing software components. Accurate specification of the component interactions in these systems is needed to ensure testability and maintainability. Moreover, standards for manufacturing systems must specify the interactions to achieve interoperability and substitutability of components. In this report we discuss approaches for specifying component interactions and examine a number of potentially useful specification techniques.

CIM Framework Experience Report for 1996

The National Advanced Manufacturing Testbed (NAMT) Framework prototype is a distributed, object-oriented manufacturing system that serves as a testbed and trial implementation for emerging industry-developed speci cations. This report documents the ndings of the Framework team in 1996 with respect to version 1.3 of SEMATECHs CIM Framework (CIMF).

The role of the database community in the national information infrastructure

The computer science community is increasingly focusing its efforts on tasks related to the National Information Infrastructure. Hardware and software advances are being sought to make wide-area networks and technological resources in general more useful to mainstream society. With this transition comes a set of unavoidable political and social issues that have never been satisfactorily dealt with in the past. Grand challenges face the computer science community on both the technical and the socio-political sides of this “major upgrade.” This paper discusses various aspects of the enormous coordination problem that faces all of us and considers what the database community can do to help.