Optical communication service is becoming a limelight in the Held of electricity supply control and management for recent years. On the one hand, most existing power manufacture communication such as control and dispa...
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ISBN:
(纸本)0863412467
Optical communication service is becoming a limelight in the Held of electricity supply control and management for recent years. On the one hand, most existing power manufacture communication such as control and dispatch systems are migrating from analog to digital formation, which requires stable data communication infrastructure with broadband capacity for ensuring upper layer signal transmission. On the other hand, the latest online business operations of power companies, such as power markets and sales information are exchanged and updated instantly, which also demands a scalable data network architecture as business expands. thus, this paper presents a case study based on an ongoing engineering project from Shanghai Municipal Electric Power Company (SMEPC). In particular, it is a system upgrade project from legacy SDH network to the latest multiservice transport platform (MSTP), along withthe major goal of broadening the capacity for the metropolitan optical communication infrastructure of SMEPC, namely the Shanghai Power Telecommunication Network (ShPTnet).
Most conventional busbar protections can not avoid the influence of current transformer saturation;therefore the paper introduces a new distributed directional busbar protection based on communication and computer tec...
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ISBN:
(纸本)0863412467
Most conventional busbar protections can not avoid the influence of current transformer saturation;therefore the paper introduces a new distributed directional busbar protection based on communication and computertechnologythat can solve the problem well. the scheme uses several distributed microprocessor protection units to collect the line's fault current direction and other data that are connected to the busbar. then through some proper logical judgments it can distinguish the busbar internal faults and external faults under different situations. It has been put into practical use and runs stable. With its low cost and simple structure, it has strong practicality in power industry.
Withthe development of web services related technologies, more and more enterprises adopt web services to encapsulate their business systems to be published on Internet. Due to the different semantic of the web servi...
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At present, adapting an Information Extraction system to new topics is an expensive and slow process, requiring some knowledge engineering for each new topic. We propose a new paradigm of Information Extraction which ...
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Principal curve pass througli the middle of a multidimensional data set. to express the distributing shape of the points in the data set, we model principal curve for it. the new method of modeling the complex princip...
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ISBN:
(纸本)9780387446394
Principal curve pass througli the middle of a multidimensional data set. to express the distributing shape of the points in the data set, we model principal curve for it. the new method of modeling the complex principal curve, based on B-spline network, is proposed. this method combines the polygonal line algorithm of learning principal curve with B-spline network. At one time, the algorithm finding a bifurcate point of the complex principal curve is presented. Our experimental results on simulate data demonstrate that it is feasible and effective.
MIGP (Medical Image Grid Platform) realizes information retrieval and integration in extensive distributed medical information systems, which adapts to the essential requirement for the development of healthcare infor...
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An increased availability and technological advances of mobile devices open up a number of ways to enable the delivery of context-aware information. In particular, position-aware context is increasingly applied to a n...
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An increased availability and technological advances of mobile devices open up a number of ways to enable the delivery of context-aware information. In particular, position-aware context is increasingly applied to a number of mobile services. this article discusses a position-aware automated context delivery to a mobile user. As a concrete field of a mobile applications, we investigate mobile tourist (MT) service. We propose a relational model for location based story generation about points of interest for MT. Parameters for a story are MT position, preset preferences by a MT, and various relationships among points of interest through their content data such as facts, categories, and keywords. We build a prototype system for Aalborg city to validate our approach. the paper presents the most important algorithms for a dynamic story generator
Current methods for selectivity estimation fall into two broad categories, synopsis-based and sampling-based. Synopsis-based methods, such as histograms, incur minimal overhead at query optimization time and thus are ...
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ISBN:
(纸本)3540329609
Current methods for selectivity estimation fall into two broad categories, synopsis-based and sampling-based. Synopsis-based methods, such as histograms, incur minimal overhead at query optimization time and thus are widely used in commercial database systems. Sampling-based methods are more suited for ad-hoc queries, but often involve high I/O cost because of random access to the underlying data. though both methods serve the same purpose of selectivity estimation, their interaction in the case of selectivity estimation for conjuncts of predicates on multiple attributes is largely unexplored. Our work aims at taking the best of both worlds, by making consistent use of synopses and sample information when they are both present. To achieve this goal, we propose HASE, a novel estimation scheme based on a powerful mechanism called generalized raking. We formalize selectivity estimation in the presence of single attribute synopses and sample information as a constrained optimization problem. By solving this problem, we obtain a new set of weights associated withthe sampled tuples, which has the nice property of reproducing the known selectivities when applied to individual predicates. We discuss different variants of the optimization problem and provide algorithms for solving it. We also provide asymptotic error bounds on the estimate. Extensive experiments are performed on both synthetic and real data, and the results show that HASE significantly outperforms both synopsis-based and sampling-based methods.
To comply with STEP-NC (ISO 14649), a new paradigm for NC programming, many computer systems involved in NC manufacture are required to reshape in both functionality and structure. this paper reports a feature-based N...
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ISBN:
(纸本)9780878494217
To comply with STEP-NC (ISO 14649), a new paradigm for NC programming, many computer systems involved in NC manufacture are required to reshape in both functionality and structure. this paper reports a feature-based NC programming system for prismatic parts to be machined using STEP-NC machine tools. the proposed system consists of three functional modules, i.e. a feature-based modeler, a process planner and a part program generator. the modeler provides a graphical environment for the part model, which is created by adding manufacturing features on a 2.5 D sweep primitive shape. the process planner determines which operations are to be performed for the features, generates workingsteps and then produces a reasonable workplan. Finally boththe geometrical and the process information are passed to the part program generator to form a complete ISO 14649-compliant file. the proposed system is demonstrated through the generation of the STEP-NC part program for an example part, and major issues such as the feature-operation mapping and the workingstep sequencing etc are also addressed in this paper.
Areito is the name of a Virtual Learning Environment (VLE) that is being set up and used by multiple educational organizations in the Dominican Republic. through Areito, it is possible to simultaneously create, manage...
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