Showing papers on "Component (UML) published in 1989"

Failure detection and identification

Abstract: Using the geometric concept of an unobservability subspace, a solution is given to the problem of detecting and identifying control system component failures in linear, time-invariant systems. Conditions are developed for the existence of a causal, linear, time-invariant processor that can detect and uniquely identify a component failure, first for the case where components can fail simultaneously, and then for the case where they fail only one at a time. Explicit design algorithms are provided when these conditions are satisfied. In addition to time-domain solvability conditions, frequency-domain interpretations of the results are given, and connections are drawn with results already available in the literature. >

Compositional model checking

Abstract: A method is described for reducing the complexity of temporal logic model checking in systems composed of many parallel processes. The goal is to check properties of the components of a system and then deduce global properties from these local properties. The main difficulty with this type of approach is that local properties are often not preserved at the global level. The authors present a general framework for using additional interface processes to model the environment for a component. These interface processes are typically much simpler than the full environment of the component. By composing a component with its interface processes and then checking properties of this composition, the authors can guarantee that these properties will be preserved at the global level. They give two example compositional systems based on the logic CTL. >

Towards a generic model of configuraton tasks

Abstract: A precise definition is provided for general configuration tasks. Two important assumptions are identified: (i) functional architecture and (ii) key component per function. A domain-independent model is presented based on these assumptions. These assumptions are shown to be both useful and tenable in real domains. They are useful because they limit the complexity of the general configuration task, determine the basic knowledge needed for solving a configuration task, and enable more efficient problem solving methods. Ideas are presented both for representing the knowledge and controlling the search. Some of these ideas were originally implemented in the Cossack expert system.

Bootstrapping in EcosystemsInternal interactions largely determine productivity and stability in biological systems with strong positive feedback

Abstract: ositive feedback is being increasingly recognized as an important component of tcosystem dynamics (DeAngelis et al. 1986, Gutierrez and Fey 1980, Pastor and Post 1988). Within the constraints of resource supply or other environmental factors, the biological system characterized by strong positive feedback among its components is in many respects self-generating-its productivity and stability determined largely through its internal interactions. "The idea of a system. . . generating [itself] in a self-consistent loop of explanation is reminiscent of the story of the boy who fell into a bog and hauled himself out by pulling on his own bootstraps, so. . . such modes of explanation [are called] 'bootstrapping' " (Davies 1983). A bootstrapping view, neither reductionist nor holistic in its basic orientation, can yield useful insights into ecosystem processes, particularly as they relate to stability and resilience. Systems characterized by strong, positive interactions among their components can be complex, productive, and quite stable under conditions to which they are adapted, but when key linkages are disrupted they are fragile and subject to threshold changes (DeAngelis et al. 1986). In this article we review recent Stable against normal disturbances, ecosystems based on close, mutual interactions may be quite vulnerable to foreign disturbances

Composing Specifications

Abstract: A rigorous modular specification method requires a proof rule asserting that if each component behaves correctly in isolation, then it behaves correctly in concert with other components. Such a rule is subtle because a component need behave correctly only when its environment does, and each component is part of the others' environments. We examine the precise distinction between a system and its environment, and provide the requisite proof rule when modules are specified with safety and liveness properties.

Organization of the human brain.

Abstract: Examination of structure-function correlates in the human brain reveals that there is a high degree of functional specificity in the information transmitted over neural systems. It also appears that the human brain has a modular organization consisting of identifiable component processes that participate in the generation of a cognitive state. The effects of isolating entire modular systems or of disconnecting the component parts can be observed. The features of a left hemisphere specialized capacity to interpret the actions of modules are discussed in terms of human consciousness.

Interests and Theories in Constitutional Choice

Abstract: The paper contrasts two interpretations of the role of agreement in politics, a social contract notion and a dialogue notion It is argued that the two notions can be viewed as complementing each other if one explicitly separates two components in human choice that in rational choice theory are often inseparably blended in the concept of preferences - an interest-component and a theory component It is suggested that the contractarian agreement notion primarily focusses on the interest-component; the dialogue notion on the theory-component in constitutional choice

A Generalization of Automobile Insurance Rating Models: The Negative Binomial Distribution with a Regression Component

Abstract: The objective of this paper is to provide an extension of well-known models of tarification in automobile insurance. The analysis begins by introducing a regression component in the Poisson model in order to use all available information in the estimation of the distribution. In a second step, a random variable is included in the regression component of the Poisson model and a negative binomial model with a regression component is derived. We then present our main contribution by proposing a bonus-malus system which integrates a priori and a posteriori information on an individual basis. We show how net premium tables can be derived from the model. Examples of tables are presented.

Building the Unified Medical Language System

Abstract: The National Library of Medicine's Unified Medical Language System (UMLS) [1] project has moved from a period of background studies and exploration of alternatives to the actual construction of the first versions of important UMLS components. This paper discusses the UMLS development strategy and assumptions, describes briefly the UMLS components as currently envisioned, and then focuses on the content of the first version of the UMLS Metathesaurus (Meta-1), its central vocabulary component.

Real-time event detection, phase identification and source location estimation using single station three-component seismic data

Abstract: Real Time Event Detection, Phase Identification and Source Location Estimation using Single Station Three Component Seismic Data

Component commonality in assemble-to-order systems: Models and properties

Abstract: This article presents a general multiperiod model of an assemble-to-order system with component commonality and proves that its solution is myopic. The model is then endowed with a capacity or storage constraint, and the resulting behavior of optimal policies is investigated. Interestingly, with such constraint, the optimal stocks of product-specific components can be lower in an assemble-to-order system than in a corresponding make-to-stock one, a behavior that is impossible in an unconstrained model.

Method and system for automated bill-of-material generation

Abstract: A computer implemented process and apparatus for selecting components of an assembly from input design specifications and displaying the selected component to a system user is provided. The selected components can be displayed in one of many formats including in a bill-of-material format. In one embodiment, the apparatus includes selection means for selecting a component from input design specifications and display means for displaying the selected assembly components.

Methodologies for optimal control of chilled water systems without storage

Abstract: In this paper, two methodologies are presented for determining the optimal control settings for chilled water systems that do not have significant thermal storage. A component-based nonlinear optimization algorithm was developed as a simulation tool for investigating optimal system performance. Results of this algorithm, implemented in a computer program, led to the development of a simpler system-based methodology for near-optimal control that is simple enough for on-line implementation

The Use of Importance-Performance Analysis as an Evaluative Technique in Adult Education

Abstract: Adult education is an area in which teaching evaluations are often required to assess instructional effectiveness. The purpose of this article is to present and illustrate a model for evaluation that will provide accurate information concerning the effectiveness of particular instructors and settings in adult education. Importance-Performance, the model used, identifies the relative importance of factors influencing student preferences (importance component) and also indicates the degree to which a particular educational setting possesses these factors (performance component).

Full text indexing based on lexical relations an application: software libraries

Abstract: In contrast to other kinds of libraries, software libraries need to be conceptually organized. When looking for a component, the main concern of users is the functionality of the desired component; implementation details are secondary. Software reuse would be enhanced with conceptually organized large libraries of software components. In this paper, we present GURU, a tool that allows automatical building of such large software libraries from documented software components. We focus here on GURU's indexing component which extracts conceptual attributes from natural language documentation. This indexing method is based on words' co-occurrences. It first uses EXTRACT, a co-occurrence knowledge compiler for extracting potential attributes from textual documents. Conceptually relevant collocations are then selected according to their resolving power, which scales down the noise due to context words. This fully automated indexing tool thus goes further than keyword-based tools in the understanding of a document without the brittleness of knowledge based tools. The indexing component of GURU is fully implemented, and some results are given in the paper.

The Environmental Component of Comprehensive Security

Abstract: properly, ’aspirations’ is sadly deficient for our (and even its) purposes in ignoring the environmental necessities and responsibilities that are corollary to them. To deal with the shortcomings of the Universal Declaration of Human Rights in defining the concept of security, we must turn to the World Charter for Nature, which reminds us that ’nature shall be respected and its essential processes ... not ... impaired’ (Article 1 ), that ’living resources shall not be utilized in excess of their natural

Multiple three dimensional facial display system

Abstract: A mutable three-dimensional facial display system is provided, constructed with a plurality of molded components constructed of a rubbery polymer or plastic material, and chosen to resemble the texture of human skin. Each component includes at least one defined structural edge which mates with adjacent components. Various alternatively shaped components are provided for each primary region of the facial display, so that seven classic face shapes and numerous hybrid variations thereof may be recreated.

Modeling defect spatial distribution

Abstract: The center-satellite model for describing the distribution of defects on wafers is discussed. This model assigns each defect to a cluster. The distribution of cluster centers on a wafer is one basic component of the model. The other basic component is the distribution of defects (satellites) about the cluster centers. Physical justification for the model is provided. Current yield models are quite accurate for VLSI designs without redundancy. A more flexible model is needed to evaluate the redundancy techniques that will be an integral part of WSI. An example is provided to demonstrate the type of analysis necessary to analyze fault-tolerant designs using the model. Empirical research needed to obtain parameters for the model is commented on, as is the need to reevaluate prior empirical research in which assumptions were made that are relaxed by the center-satellite model. >

A synthesis strategy for mechanical devices

Abstract: Good mechanical designs are often composed of highly integrated, tightly coupled components in which the interactions among the components are essential to the function and economic execution of the design. This assertion runs counter to design methodologies in other engineering fields, such as software design and circuit design, that advocate designs in which each component fulfills a single function with minimal interaction. Because of the geometry, weight, and cost of mechanical components, converting a single functional requirement into a single component is usually not practical. Each component may contribute to the performance of more than one function, and the performance of each function may be distributed over many components. In fact, most mechanical components perform not only the desired function, but also have many additional, unintended behaviors. In good mechanical designs, these additional behaviors often are exploited. We describe a synthesis strategy to utilize these behaviors by transforming design specifications in a function-preserving manner to obtain function structures which correspond closely to collections of available components. This strategy is elaborated in the context of simple gearbox design. We feel that design strategies derived from characteristics of good designs will foster improved design practice and facilitate the development of computer-based assistance to the designer.

Integrated manufacturing system

Abstract: A method of manufacturing an article includes constructing a definition of the article in a computer memory and further defining in the computer memory from the definition of the article, a plurality of tools for forming component parts of the article. The definition of the plurality of tools is downloaded to a tool forming device which is then operated to form the plurality of tools. The component parts of the article are then formed utilizing the plurality of tools.

Modeling adaptive biological systems.

Abstract: During the evolution of many systems found in nature, both the system composition and the interactions between components will vary. Equating the dimension with the number of different components, a system which adds or deletes components belongs to a class of dynamical systems with a finite dimensional phase space of variable dimension. We present two models of biochemical systems with a variable phase space, a model of autocatalytic reaction networks in the prebiotic soup and a model of the idiotypic network of the immune system. Each model contains characteristic meta-dynamical rules for constructing equations of motion from component properties. The simulation of each model occurs on two levels. On one level, the equations of motion are integrated to determine the state of each component. On a second level, algorithms which approximate physical processes in the real system are employed to change the equations of motion. Models with meta-dynamical rules possess several advantages for the study of evolving systems. First, there are no explicit fitness functions to determine how the components of the model rank in terms of survivability. The success of any component is a function of its relationship to the rest of the system. A second advantage is that since the phase space representation of the system is always finite but continually changing, we can explore a potentially infinite phase space which would otherwise be inaccessible with finite computer resources. Third, the enlarged capacity of systems with meta-dynamics for variation allows us to conduct true evolution experiments. The modeling methods presented here can be applied to many real biological systems. In the two studies we present, we are investigating two apparent properties of adaptive networks. With the simulation of the prebiotic soup, we are most interested in how a chemical reaction network might emerge from an initial state of relative disorder. With the study of the immune system, we study the self-regulation of the network including its ability to distinguish between species which are part of the network and those which are not.

Integrated aircraft manufacturing system

Abstract: A method of manufacturing aircraft includes constructing a definition of the aircraft in a computer memory and then defining in the memory a first tool for forming a component part of the aircraft and a second tool for assembling a component part made with the first tool. The definitions of the first and second tools are downloaded to a tool forming device which is operated to form the first and second tools essentially independent from one another.

Situation monitoring for active databases

Abstract: paper is concerned with ways of specifying situations and evaluating them efficiently. The techniques described in this paper were developed as part of the HiPAC (High Performance Active) DBMS. a prototype active DBMS (DAYA88a. DAYA88b. CHAK89], parts of which have been implemented. However. the algebra and transformations described in this paper can be applied more generally. The situation evaluation mechanism can either be a component integrated tightly with a DBMS. or coupled with a heterogeneous array of applications or databases that signal it when specified events occur. We present a basis for efficiently evaluating the situation (event and condition) portion of situation/action rules. either in an active database or in a standalone situation monitor. A common framework handles situations involving both database changes and nondatabase situations. We introduce ARelations to represent net changes to a stored or derived relation. We define an operator that computes ARelations for derived relations. Evaluation of expressions involving changes is optimized by defining incremental forms of relational operators and by providing a chain rule that extends incremental computation to data derived by arbitrary expressions.

Modification of the split-flux formulae for mean daylight factor and internal reflected component with large external obstructions

Abstract: The original split-flux formulae take into account external obstructions which form a horizontal band. The formulae are extended in this Note to include large vertical obstructions, such as projecting wings of a building, and overhanging canopies. They incorporate a more detailed assessment of light reflected from obstructions.

Integrated assembly system

Abstract: A method of assembling the separate components of a multi-component article includes generating a master definition of the article as a graphic data set in a 3-dimensional graphics computer system including coordinate points precisely locating the design definition in a three dimensional coordinate system. Data sub sets of the master definition are selected for component parts of the article including coordinate points. The data sub sets are transferred to a tool and component parts of the article are formed on the tool utilizing the data sub sets. The formed parts include physical markings thereon corresponding to the coordinate points of the master design definition. The data sub set are further downloaded to a microprocessor controlled measuring device. The measuring device is calibrated to the master design definition utilizing the physical markings on one of the parts. Further of the parts are then located with respect to other of the parts by utilizing their physical markings and referencing these marking back to the master design definition via the microprocessor controlled measuring device.