the objective of this paper is to present an optimal design methodology to determine the best firing strategy, energy store sizing, energy store spacing and maximum system efficiency for a distributed Energy Store (DE...
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the objective of this paper is to present an optimal design methodology to determine the best firing strategy, energy store sizing, energy store spacing and maximum system efficiency for a distributed Energy Store (DES) railgun. System simulations/designs will be based on the assumption that switching of the energy storage units will be accomplished using solid state devices. Candidate semiconductor technologies are promising in relation to solving the high energy, low weight requirements of a railgun system and other pulsed power systems requiring high energy, compact switching. A simulation code has been developed and used to produce non-dimensional data files that are then scaled to physical railgun values based on input parameters. Energy stores are assumed to be capacitive in nature with diodes to prevent negative currents and crowbar diodes to prevent voltage reversal of the capacitors. the main thrust of this simulation effort is to produce a DES design that optimizes the efficiency of the conversion of stored electrical energy to projectile kinetic energy, while also considering the abilities of near term solid state switching devices.
As we have applied object-oriented technology to larger and more complex systems, we have realized the need for capabilities not readily supported by current object-oriented programming environments. the concept of th...
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ISBN:
(纸本)0897917219
As we have applied object-oriented technology to larger and more complex systems, we have realized the need for capabilities not readily supported by current object-oriented programming environments. the concept of the object engine is to provide an object-oriented environment in which to integrate different problems-solving paradigms and provide or incorporate support mechanisms such as persistence, garbage collection, testing tools and distributed concurrent processing. Standardization of the object engine would facilitate integration of independently developed applications and components and could lead to the development of hardware support to improve performance. Participants in this workshop discussed advanced features they have explored and/or have recognized as shortcomings of existing environments. this year, participants developed a refined list of capabilities which should be included in an object engine.
the proceedings contain 37 papers. the special focus in this conference is on Fundamentals of Computation theory. the topics include: Discrete time process algebra with abstraction;a duration calculus with infinite in...
ISBN:
(纸本)3540602496
the proceedings contain 37 papers. the special focus in this conference is on Fundamentals of Computation theory. the topics include: Discrete time process algebra with abstraction;a duration calculus with infinite intervals;a delegation-based object calculus with subtyping;model-checking for rual-time systems;on polynomial ideals, their complexity, and applications;rewriting regular inequalities;a simple abstract semantics for equational theories;processes with multiple entries and exits;efficient rewriting in cograph trace monoids;effective category and measure in abstract complexity theory;about planar cayley graphs;on condorcet and median points of simple rectilinear polygons;fast algorithms for maintaining shortest paths in outerplanar and planar digraphs;growing patterns in 1D cellular automata;petri nets, commutative context-free grammars, and basic parallel processes;implementation of a UU-algorithm for primitive recursive tree functions;dummy elimination;computing petri net languages by reductions;categorial graphs;effective systolic algorithms for gossiping in cycles and two-dimensional grids;restarting automata;optimal contiguous expression dag evaluations;communication as unification in the petri box calculus;distributed catenation and chomsky hierarchy;the power of frequency computation;randomized incremental construction of simple abstract voronoi diagrams in 3-space;properties of probabilistic pushdown automata;formal parametric equations;some results concerning two-dimensional turing machines and finite automata;how hard is to compute the edit distance;on the synchronization of semi-traces;tiling with bars and satisfaction of boolean formulas and axiomatizing petri net concatenable processes.
We describe the design of Mariposa, an experimental distributed data management system that provides high performance in an environment of high data mobility and heterogeneous host capabilities. the Mariposa design un...
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ISBN:
(纸本)0818654007
We describe the design of Mariposa, an experimental distributed data management system that provides high performance in an environment of high data mobility and heterogeneous host capabilities. the Mariposa design unifies the approaches taken by distributed file systems and distributed databases. In addition, Mariposa provides a general, flexible platform for the development of new algorithms for distributed query optimization, storage management, and scalable data storage structures. this flexibility is primarily due to a unique rule-based design that permits autonomous, local-knowledge decisions to be made regarding data placement, query execution location, and storage management.
Many organizations have major investments in information systems, ranging from legacy programs written in COBOL to newer relational database management systems. these distributed heterogeneous information systems (DHI...
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ISBN:
(纸本)0818654007
Many organizations have major investments in information systems, ranging from legacy programs written in COBOL to newer relational database management systems. these distributed heterogeneous information systems (DHISs) do not generally interoperate or share information. However, commercial-off-the-shelf (COTS) software products are becoming available that can make DHISs appear as though they were a single integrated system. MITRE recently completed an internal project that examined two COTS DHIS integration products in a test environment consisting of six information systems, and two clients running on eight platforms in three cities. based on this prototyping effort, we believe that there are many applications in which DHIS integration technologies would be appropriate. Our presentation will include an overview of our prototypes, a description of the work we have done, and a summary of the lessons learned.
Optical fibres, which have been developed for long distance, high bandwidthcommunications, possess a very low loss, are cheap to manufacture and are readily available in longlengths.
ISBN:
(纸本)0819416991
Optical fibres, which have been developed for long distance, high bandwidth
communications, possess a very low loss, are cheap to manufacture and are readily available in long
lengths.
In this paper we present an experimental evaluation of a quasi-distributed fiber-optic strain and temperature sensor system based on time division multiplexing. the system relies on an advanced dual-core fiber to whic...
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ISBN:
(纸本)0819416991
In this paper we present an experimental evaluation of a quasi-distributed fiber-optic strain and temperature sensor system based on time division multiplexing. the system relies on an advanced dual-core fiber to which a set of Fabry-Perot interferometers is introduced with fiber Bragg gratings used as weak reflectors.
A federated database management system (FDBMS) is a special type of distributed database system that enables existing local databases, in a heterogeneous environment, to maintain a high degree of autonomy. One of the ...
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ISBN:
(纸本)0818654007
A federated database management system (FDBMS) is a special type of distributed database system that enables existing local databases, in a heterogeneous environment, to maintain a high degree of autonomy. One of the key problems in this setting is the coexistence of local transactions and global transactions, where the latter access and manipulate data of multiple local databases. In modeling FDBMS transaction executions we propose a more realistic model than the traditional read/write model;in our model a local database exports high-level operations which are the only operations distributed global transactions can execute to access data in the shared local databases. Such restrictions are not unusual in practice as, for example, no airline or bank would ever permit foreign users to execute ad hoc queries against their databases for fear of compromising autonomy. the proposed architecture can be elegantly modeled using the multilevel nested transaction model for which a sound theoretical foundation exists to prove concurrent executions correct. A multilevel scheduler that is able to exploit the semantics of exported operations can significantly increase concurrency by ignoring pseudo conflicts. A practical scheduling mechanism for FDBMSs is described that offers the potential for greater performance and more flexibility than previous approaches based on the read/write model.
Concerns the technology and methods for integrating an application that is event-based, whether that application is being constructed from scratch or is a synthesis of existing event-basedsystems. Developing an event...
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Concerns the technology and methods for integrating an application that is event-based, whether that application is being constructed from scratch or is a synthesis of existing event-basedsystems. Developing an event-based application is a complex task for programmers, who must address several issues not found in traditional systems, and, currently, must do so without much assistance. In this paper, we broaden the technology for integration to encompass event-based programming. A method is presented for separating event-based interaction properties from the implementation of the application modules, so that system integration can be performed using only the abstractions. then, based upon the abstract aggregate, all interface software needed to validly implement the system is generated automatically. A software bus model is enhanced to accommodate the models which drive event-baseddistributed applications. In this way, designers may define complex event-based interaction abstractly, making it easier to integrate and experiment withevent-baseddistributed applications.< >
We describe the design of Mariposa, an experimental distributed data management system that provides high performance in an environment of high data mobility and heterogeneous host capabilities. the Mariposa design un...
详细信息
We describe the design of Mariposa, an experimental distributed data management system that provides high performance in an environment of high data mobility and heterogeneous host capabilities. the Mariposa design unifies the approaches taken by distributed file systems and distributed databases. In addition, Mariposa provides a general, flexible platform for the development of new algorithms for distributed query optimization, storage management, and scalable data storage structures. this flexibility is primarily due to a unique rule-based design that permits autonomous, local-knowledge decisions to be made regarding data placement, query execution location, and storage management.< >
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