A reasoning procedure using quantitative models of connectivity and function has been developed to generate automatically multibranched diagnostic trees which can isolate faults within feedback loops and in the presen...
详细信息
A reasoning procedure using quantitative models of connectivity and function has been developed to generate automatically multibranched diagnostic trees which can isolate faults within feedback loops and in the presence of multiple faults. The authors describe how the model-based reasoning system is used to generate automatically diagnostic trees that can have variable degrees of branching, from binary to ternary (nodes with high, OK, and low branches) to n-ary trees. With branching degrees at or above ternary, these trees are capable of fault isolating within loops and can in fact isolate multiple faults. The trees can utilize much of the information content in quantitative measurements to make efficient and accurate diagnoses not possible with the binary tree. Both efficiency and accuracy of diagnosis increase with the branching factor of the tree. Automated tree generation provides effective automated diagnostics to applications requiring low-cost hardware and fast response time.< >
The ability of automatic test equipment (ATE) to introspectively assess its own well-being as well as assess the well-being of the UUTs (units under test) external to itself has long been understood to be a major adva...
详细信息
The ability of automatic test equipment (ATE) to introspectively assess its own well-being as well as assess the well-being of the UUTs (units under test) external to itself has long been understood to be a major advantage of offline ATE. The author argues that this inherent potential ATE system capability has not been used effectively. It has been treated as an afterthought and implemented by the most prosaic of methods. The results of this inadequate and inappropriate treatment of ATE self-test has been stagnation in improved MTBF of new ATE systems and regression in MTTR. The maintenance and training problems for new and modern ATE have been exacerbated rather than reduced. The author contends that this situation is a result of neglect and apathy on the part of ATE systems developers who have failed to be innovative or attentive to modern system techniques in the design of self-test for their ATE. The author proposes a five-phase ATE self-test approach that he hopes can resolve the above-mentioned problems. The phases are: pre-ATE planning; ATE planning; self-test implementation; self-test maturity and evaluation; and self-test feedback/archiving.< >
The ability to quickly model the production implications of changes from marketing, sales, finance, or engineering allows manufacturing enterprises to be pro-active in building competitive advantage. The power of a ra...
ISBN:
(纸本)9780911801583
The ability to quickly model the production implications of changes from marketing, sales, finance, or engineering allows manufacturing enterprises to be pro-active in building competitive advantage. The power of a rapid modeling approach that assists manufacturing system designers and planners to evaluate their factory production systems is illustrated here. The study demonstrates how various members of an interdiciplinary design and analysis team can evaluate the process capabilities before introducing new methods and machines.
The SimKitTM system is an integrated set of general-purpose simulation and modeling tools built in and on the Knowledge Engineering Environment R (KEER) software development system. SimKit is used to build "knowl...
ISBN:
(纸本)9780911801583
The SimKitTM system is an integrated set of general-purpose simulation and modeling tools built in and on the Knowledge Engineering Environment R (KEER) software development system. SimKit is used to build "knowledge-based" simulations. By knowledge-based, we mean an approach that utilizes a variety of techniques that have emerged from artificial intelligence including: • The LISP programming environment • High-resolution bitmap graphics • Object-oriented programming • Frame-based knowledge representation with inheritance • Active values or "demons" • Rule-based reasoning. Knowledge-based simulations are more understandable, interactive, accessible, and extensible than simulations built using "conventional" techniques. In addition, knowledge-based simulations can easily be integrated with other knowledge system applications.
This paper deals with methods for constructing and solving large Markov chain models of computer system availability and reliability. A set of powerful high level modeling constructs is discussed that can be used to r...
ISBN:
(纸本)9780911801583
This paper deals with methods for constructing and solving large Markov chain models of computer system availability and reliability. A set of powerful high level modeling constructs is discussed that can be used to represent the failure and repair behavior of the components that comprise a system, including important component interactions. If time independent failure and repair rates are assumed then a time homogeneous continuous time Markov chain can be constructed automatically from the modeling constructs used to describe the system. Since, the size of Markov chains grows exponentially with the number of components modeled, simulation appears to be a practical way for solving models of large systems. However, the standard simulation takes very long simulation runs to estimate availability and reliability measures because the system failure event is a rare event. Therefore, variance reduction techniques which can aid in computing rare-event probabilities quickly are of interest. Specifically, the Importance Sampling technique has been found to be most useful. The modeling language and the simulation methods discussed in this paper have been implemented in a program package called the system Availability Estimator (SAVE).
This paper focuses on the role of the production scheduler in developing and using a computer simulation based scheduling system. As the scheduling system end user, the production scheduler is responsible for developi...
ISBN:
(纸本)9780911801583
This paper focuses on the role of the production scheduler in developing and using a computer simulation based scheduling system. As the scheduling system end user, the production scheduler is responsible for developing schedules which support the business goals of the manufacturing facility. To do so, he must balance many conflicting objectives relating to work-in-process inventory levels, resource utilizations, and customer service. During any single scheduling period, the desired balance may vary with time or across production resources. Simulation based scheduling does not provide an optimum solution, but provides visibility into the effects of decisions. The production scheduler uses this information to perform analyses and to identify opportunities to improve the plan. His participation during system development ensures that the model and reports fully support these activities. While the schedule generation and revision process can be automated, the final analysis of the value of the resulting schedule requires human involvement. A FACTOR scheduling software application is reviewed to illustrate the role of the user in this dynamic environment.
The U.S. Army is evaluating the conversion of all of its conventional medical radiological imaging capabilities to a filmless technology using a Digital Imaging Network system (DINS) in both fixed and field hospitals....
ISBN:
(纸本)9780911801583
The U.S. Army is evaluating the conversion of all of its conventional medical radiological imaging capabilities to a filmless technology using a Digital Imaging Network system (DINS) in both fixed and field hospitals. The latter hospitals are called Deployable Combat Medical Facilities. Using DINS, the photosensitive films presently used to record and display x-ray images would be replaced by digitized images stored on either magnetic or optical devices and displayed on computer workstations (electronic lightboxes). This document describes the use of a simulation model as a tool in estimating the imaging caseload for field hospitals for the purpose of determining the required image storage capacities of the DINS workstations and the required throughput capacity of the inter-workstation local area network. The simulation follows a patient through the five echelons of field hospitals, recording the number of radiological images created in each ward of a hospital and the inter-ward movement of images. The simulation also provides information about the number of images transferred with a patient being evacuated to rear area hospitals. The detail included in the simulation model makes it possible to analyze the utilization of facilities within a hospital and the impact of queuing on patient care when these facilities are overloaded. Three simulation examples are presented that examine the impact on an Echelon 3 EVAC Hospital of the treatment of patients with combat-related injuries.
Architectural concepts evolving from the general architectural principals adopted by the ISO OSI reference-modeling effort are applied to C3 (command, control, and communication) systems. The resulting C3 reference mo...
详细信息
Architectural concepts evolving from the general architectural principals adopted by the ISO OSI reference-modeling effort are applied to C3 (command, control, and communication) systems. The resulting C3 reference model describes a framework for the evolution of a coordinated and detailed definition of C3 discipline addressing complete C3 systems, their resources, and inherent interactions. It includes generic and analog extensions to the ISO OSI reference model (RM). As such, it requires reinterpretations and generalizations that go far beyond the scope of the ISO OSI RM. The C3 RM includes the ISO OSI RM by adapting it for the communications types of interactions. In parallel, layers of three other complimentary types of isomorphic interactions also provide services to the application layer.
In this tutorial, the author describes a powerful modeling tool which can dramatically reduce the amount of time it takes to simulate a computer system. The Network II.5 world view and the class of problems it address...
详细信息
In this tutorial, the author describes a powerful modeling tool which can dramatically reduce the amount of time it takes to simulate a computer system. The Network II.5 world view and the class of problems it addresses are discussed. A summary of Network II.5 capabilities is presented. To tie the tutorial concepts together, an example of using Network II.5 is included.< >
暂无评论