39755599
Advanced structural joins using element distribution
For accelerating a structural join operation, current techniques focus on skipping elements that do not contribute to the results. They make use of external index structures (e.g. B+ tree) to determine a bunch of elements to be skipped. However, external indexes are too heavy for a structural join and the overhead of index lookups can reduce the benefit of skipping. In this paper, we proposed element trees and distribution encoded bitmaps for efficient element skipping. With proposed techniques, we can exploit the distribution of elements as well as the context information of a query for efficient skipping of unnecessary elements.
27100927
Efficient structural joins with clustered extents
In order to retrieve an extent in the first step, inverted index built on selection predicates is us For each selection predicate, an extent can be e retrieved by looking up the inverted index. Finding occurrences of the s tructural matches in th second step is a core operation in XML query proce ing. To solve this sub-problem, Zhang et al. [6] p posed the multi-predicate merge join (MPMGJN) gorithm, which is an extension of the traditional mer join algorithm. Al-Khalifa et al. [1] generalized th MPMGJN algorithm to the tree-merge join algorithm that consider the order of join results. Furthermo they proposed the stack-tree join algorithms that improve the tree-merge join algorithms. Those al rithms are dependent on the representation of p tions of XML elements (and string values) to det mine structural relationships between tree nodes. cently, Chien et al. [3] proposed a structural join alg
20202426
Integration of a Structural Index with a Structural Join for Accelerating Path Queries
Current techniques for processing XML queries can be divided into two groups. One is structural index techniques that reduce the search space by traversing a structural summary instead of a data graph. And the other is structural join techniques that can efficiently compute ancestor-descendant pairs from two lists of nodes without traversing the data graph. In this paper, we propose a structural index technique and a novel structural join technique and we prove that these two proposed techniques are integrated to accelerate processing of a path query in the experiments.
27330844
Efficient processing of regular path joins using PID
Abstract XML is data that has no fixed structure. So it is hard to design a schema for storing and querying an XML data. Instead of a fixed schema, graph-based data models are widely adopted for querying XML. Queries on XML are based on paths in a data graph. A meaningful query usually has several paths in it, but much of recent research is more concerned with optimizing a single path in a query. In this paper, we present an efficient technique for processing multiple path expressions in a query. We implemented our technique and present preliminary performance results.
1514813
Temporal Query Processing Using Spatially-Partitioned Method
In this paper, we propose a general spatiallypartitioned temporal operation model, called 3D-TOM, and partition-based join algorithms for various types of temporal join in the proposed model. The temporal operators addressed in this paper include overlap, precede, follow, and equal. Some factors which a ect the performance of the proposed method are also discussed.
16878992
Improving use case driven analysis using goal and scenario authoring: A linguistics-based approach
Use case driven analysis does not facilitate effective requirements elicitation or provide rationale for the various artifacts that get generated during the requirements analysis phase. On the other hand, goal and scenario based approach is considered to be effective for elicitation but it does not lead to use cases. This paper discusses how to combine goal and scenario based requirements elicitation technique with use case driven analysis using natural language concepts. In our proposed approach, four levels of goals, scenario authoring rules, and linguistic techniques have been developed to identify use cases from text based goal and scenario descriptions. The artifacts resulting from our approach could be used as input to a use case diagramming tool to automate the process of use case diagram generation.
6065142
On effective data clustering in bitemporal databases
Temporal databases provide built-in supports for efficient recording and querying of time-evolving data. In this paper, data clustering issues in temporal database environment are addressed. Data clustering is one of the most effective techniques that can improve performance of a database system. However, data clustering methods for conventional databases do not perform well in temporal databases because there exist crucial differences between their query patterns. We propose a data clustering measure, called Temporal Affinity, that can be used for the clustering of temporal data. The temporal affinity, which is based on the analysis of query patterns in temporal databases, reflects the closeness of temporal data objects in viewpoints of temporal query processing. We perform experiments to evaluate the proposed measure. The experimental results show that a data clustering method with the temporal affinity works better than other methods.
8711882
SimFlex: a fast, accurate, flexible full-system simulation framework for performance evaluation of server architecture
The new focus on commercial workloads in simulation studies of server systems has caused a drastic increase in the complexity and decrease in the speed of simulation tools. The complexity of a large-scale full-system model makes development of a monolithic simulation tool a prohibitively difficult task. Furthermore, detailed full-system models simulate so slowly that experimental results must be based on simulations of only fractions of a second of execution of the modelled system.This paper presents SIMFLEX, a simulation framework which uses component-based design and rigorous statistical sampling to enable development of complex models and ensure representative measurement results with fast simulation turnaround. The novelty of SIMFLEX lies in its combination of a unique, compile-time approach to component interconnection and a methodology for obtaining accurate results from sampled simulations on a platform capable of evaluating unmodified commercial workloads.
12043862
A method and tool support for variant requirements analysis: goal and scenario based approach
Identifying and representing variant requirements among products in a product family are crucial activities for a successful software reuse. The variant requirements should be not only identified based on the business goal, which drives marketing plan, product plan, and differences among products, but also represented as familiar notations in order to support developing a particular product in the product family. Thus, our proposal is to identify the variant requirements through goals and scenarios, and represent them as variable use cases for a product family. Especially, for identification of the variant requirements, we propose four abstraction levels of requirements in the product family, and goal and scenario modeling. For representation of them, variable use case model is suggested, and also the use case transfer rules are proposed so as to bridge the gap between the identification and representation activity. The paper illustrates the application of the approach within a supporting tool, namely DREAM (Domain REquirements Analysis Method) using the ATM example.