The authors describe the architecture and the main features of a multimedia computer supported cooperative work environment (MCSCWE) and its application in requirements engineering. The MCSCWE has been utilized in sev...
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The authors describe the architecture and the main features of a multimedia computer supported cooperative work environment (MCSCWE) and its application in requirements engineering. The MCSCWE has been utilized in several requirements engineering activities, and the use of the MCSCWE in a case study conducted for the Sacramento Area Council of Governments (SACOG) is presented. For the SACOG case study, 85 participants were convened by SACOG and divided into seven spatially distributed groups working on the same problem sets, i.e., the problem of coming up with a strategic plan to reduce congestion and meet clean air requirements as required by Federal law. The results of the case study demonstrate that the MCSCWE was effective and efficient in assisting this group to come to consensus on the issues and strategies necessary to achieve these goals.< >
With the Navy leaning towards a smaller but better trained force, using simulators in training becomes a cost effective way of keeping our military edge. Several innovations are being utilized in today's simulator...
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With the Navy leaning towards a smaller but better trained force, using simulators in training becomes a cost effective way of keeping our military edge. Several innovations are being utilized in today's simulators. Hardware and software designs now include distributed computer architectures, real-time, multi-tasking operating systems, flexible generic consoles, commercial off-the-shelf equipment, standard real-time ocean acoustic models, and standard acoustic data bases. This paper describes these technologies and their innovative application in the Navy's newest Anti-Submarine Warfare team Trainer, Device 14A12. Device 14A12 simulates sonar, fire control, electronic warfare, bridge, ownship aircraft and Naval Tactical Data systems (NTDS) for 16 surface ownship classes. Device 14A12 also simulates multiple air, surface and subsurface threat, neutral and friendly platforms as well as missiles and torpedoes. The innovative modeling of these systems along with Device 14A12's enormous flexibility will allow the Navy to provide effective tactical training for the surface fleet now and in the future.
Electromagnetic interference (EMI) is one of the major contributors to mission degradation in our fleet today due to the increase in population and sensitivity of both topside and below deck electronic systems. Sensit...
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Electromagnetic interference (EMI) is one of the major contributors to mission degradation in our fleet today due to the increase in population and sensitivity of both topside and below deck electronic systems. Sensitive combat systems designed to counter intelligent and deceptive targets can be confused by the complex intra-ship EM environment. This can cause identification failure or losing "track" of a hostile or incoming missile or even engaging "friendly targets." Topside design and integration efforts have been used to reduce EMI, but this is not the total solution to the problem. A program of total ship and system EMI assessment and control must be implemented. This program must exploit electromagnetic compatibility (EMC) optimization in electronic circuit design and take advantage of and (in some cases) direct topside shapes and structures to control the propagation of desired and undesired EM energy. Positive and active control of EM design characteristics are absolutely required before optimum combat system effectiveness can be realized. This paper will describe the current topside design process, EMC improvements being made, and how the process is being integrated into, and is dependent upon, the ship design process. It will give examples of some of the major mission degrading EMI problems in the fleet today and how past problems were solved with existing EM analysis programs. It will also discuss the control of EM energy in new design through the use of techniques being developed such as ray tracing and ray casting. The paper projects where the challenges lie for future topside and EM engineering designers and describes how the equipment technology transfer process must be better integrated to meet the challenge of effective EMI control.
Although there are several efforts underway to build multilevel secure relational database management systems, there is no clear consensus regarding what a multilevel secure relational data model exactly is. In part t...
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The authors present a secure kernelized architecture for multilevel object-oriented database management systems. The architecture is based on the notion of a message filter. It builds upon the typical architecture of ...
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A taxonomy is presented of knowledge-based approaches to fault management for telecommunications networks. Fault management systems are first characterized as multistage process systems. Using this characterization, a...
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A taxonomy is presented of knowledge-based approaches to fault management for telecommunications networks. Fault management systems are first characterized as multistage process systems. Using this characterization, a discussion is presented of a variety of current systems reported in the open literature that implement automated fault management and which span all processing stages (from alarm receipt to fault correction). The authors then focus on the diagnostic stage of each system and categorize the methods in terms of the major artificial intelligence methods employed. They conclude by considering an apparent trend in automated fault management systems toward an increased use of semantic knowledge and other approaches to describe network behavior. The emphasis throughout is on the use of information technology for automating fault management, rather than on engineering-level details of any specific subsystem.< >
It is argued that predisposed assumptions in security policy models can leave holes in the security aspects of the informationsystems that are based on them. In particular, informationsystems based only on the Bell-...
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It is argued that predisposed assumptions in security policy models can leave holes in the security aspects of the informationsystems that are based on them. In particular, informationsystems based only on the Bell-LaPadula model (D.E. Bell and L.J. LaPadula, 1976) pose potential problems by allowing new threats to be built in them because the policies are incomplete. A comparison of manual and automated systems is used to demonstrate the derivation of the Bell-LaPadula star-property for automated systems and its analog for manual systems. This exercise aids in producing a policy model based on needs and a perspective on the limitations of classical security policy models.< >
Presents a novel decomposition algorithm that breaks a multilevel relation into single-level relations and a novel recovery algorithm which reconstructs the original multilevel relation from the decomposed single-leve...
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Presents a novel decomposition algorithm that breaks a multilevel relation into single-level relations and a novel recovery algorithm which reconstructs the original multilevel relation from the decomposed single-level relations. There are several novel aspects to these decomposition and recovery algorithms which provide substantial advantages over previous proposals. The algorithms are formulated in the context of an operational semantics for multilevel relations, defined here by generalizing the usual update operations of structured query language (SQL) to multilevel relations. The algorithms, with minor modifications, can easily accommodate alternative update semantics which have been proposed in the literature. The algorithms are efficient because recovery is based solely on union-like operations without any use of joins. The decomposition is intuitively and theoretically simple, giving a sound basis for correctness.< >
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