In this paper, we analyse the data access characteristics of a typical XML information retrieval system and propose a new query aware buffer replacement algorithm based on prediction of Minimum Reuse Distance (MRD for...
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In this paper, we analyse the data access characteristics of a typical XML information retrieval system and propose a new query aware buffer replacement algorithm based on prediction of Minimum Reuse Distance (MRD for short). The algorithm predicts an object's next reference distance according to the retrieval system's running status and replaces the objects that have maximum reuse distances. The factors considered in the replacement algorithm include the access frequency, creation cost, and size of objects, as well as the queries being executed. By taking into account the queries currently running or queuing in the system, MRD algorithm can predict more accurately the reuse distances of index data objects.
The requirements of OLAP applications increase rapidly by dramatically increased data volume, users, query volume and query complexity. The requirement for shortening update period in data warehouse is another crucial...
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The requirements of OLAP applications increase rapidly by dramatically increased data volume, users, query volume and query complexity. The requirement for shortening update period in data warehouse is another crucial factor for a scalab.e OLAP application. In this paper, we propose a scalab.e OLAP prototype to support the query processing with increasing data volume by distributing the whole fact tuples to multiple servers to construct a set of sibling cubes which can be merged together to obtain the whole cube. We employ a light weight distribution policy with fully duplicated dimension tables in each sibling server on the observation of very low proportion of space cost for dimension tables. OLAP query with distributed aggregate functions can be transformed into queries to be performed parallel in sibling servers. For non-distributed computing aggregate functions, such as median, the optimized median aggregate computing algorithm is proposed to reduce transmission volume between servers while computing the global median values. We also present a three-level framework in data warehouse to meet the requirement of shorter update period in "operational business intelligence". An asynchronous tunnel model is proposed to reduce update latency by pre-fetching updated tuples to OLAP processing server. Finally, we set up prototype system ParaCube to evaluate performance in SN (shared-nothing) system and multi-core platforms.
Based on a Space-Time Block Coding Multi-Carrier Code Division Multiple Access (STBC MC-CDMA) system, a Asynchronous Distributed Pricing (ADP) Algorithm is studied in this paper, in which the cognitive radio(CR) users...
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Silicon is used as a substrate for photovoltalc conversion of energy and the photovoltalc properties of the polycrystalline silicon depend mainly on the crystalline structure (grain size and presence of defects) and o...
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ISBN:
(纸本)9781622762866
Silicon is used as a substrate for photovoltalc conversion of energy and the photovoltalc properties of the polycrystalline silicon depend mainly on the crystalline structure (grain size and presence of defects) and of the purity of the material. Off-spec scrap silicon from the semiconductor industry is used as solar grade silicon (SOG-Si). However, because it is difficult to secure a steady supply of this material, development of a process to produce at low cost silicon is therefore definitely necessary. In this research, the technique of silicon purification in an electron beam furnace was used, where the melting occurs in a high vacuum and the impurities were extracted by evaporation. Metallurgical grade silicon (MG-Si) in the granulose form with leaching, with an initial purity of 99. 88% in mass were used as starting materials. The final purity was above 99.99% in mass. This result demonstrated that this process was technically viable. This paper mainly studied the impurity distribution in the sample and the macro-and microstructure of the sample after electron beam melting. Meantime, the growth mechanism of crystal was also discussed.
The decolorization of Reactive Red K-2BP wastewater with sponge iron in a fixed-bed column system was evaluated at different influent water qualities (pH, dye concentration), particle diameter of sponge iron and filtr...
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Partial order reduction techniques have been used to combat the state explosion problem in model checking procedures for concurrent systems with probabilistic behaviors. There are some results that give criteria on ap...
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This paper proposes a generalized model by extending Markov chain with spatial resources lab.ls, which can describe the functional and performance properties and some basic characteristics such as nondeterminacy and r...
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There are many influence factors for coal and gas outburst, in which the stress wave is the most important one of the non-geological factors. Using the implicit-explicit analytical function of ANSYS/LS-DYNA, the respo...
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In order to respond to algebraic attacks, it is important to construct Boolean functions with high algebraic immunity of the graphs. In this paper, the complicated problem of algebraic immunity of the graph is convert...
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ISBN:
(纸本)9789881701282
In order to respond to algebraic attacks, it is important to construct Boolean functions with high algebraic immunity of the graphs. In this paper, the complicated problem of algebraic immunity of the graph is converted to the simpler problem of annihilators of the single-output assistant function. Based on this, we propose a new method for constructing single-and multi-output Boolean functions with high algebraic immunity of the graphs. This method can also give many more general single-output Boolean functions with maximum algebraic immunity.
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