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.
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
12500430
Energy-efficient file placement techniques for heterogeneous mobile storage systems
While hard disk drives are the most common secondary storage devices, their high power consumption and low shock-resistance limit them as an ideal mobile storage solution. On the other hand, flash memory devices overcome the main problems of hard disk drives, but they are still more expensive in the cost per bit over hard disk drives and can only support a limited number of erase cycles. In this paper, we show that combining the merits of a hard disk and a flash memory device can produce an energy-efficient secondary storage solution for mobile platforms. We propose an energy-efficient file placement technique for such heterogeneous storage systems. The proposed technique adapts an existing data concentration technique by separating read and write I/O requests. Experimental results show that the proposed technique reduces the energy consumption by up to 74.5% when the combination of a 1.8" disk and a flash memory is used instead of a single 2.5" disk, at the cost of small increase in the average response time.
3831285
Data Integration Hub for a Hybrid Paper Search
In this paper we describe the design of a hybrid search that combines simple metadata search with a traditional keyword search over unstructured context data. This paradigm provides the inquirer additional options to narrow the search with some semantic aspects through the XML metadata query. We demonstrate a paper search for a case study of the hybrid search, and describe a data integration hub to integrate those data dispersed on the Net.
1639978
ViChaR: A Dynamic Virtual Channel Regulator for Network-on-Chip Routers
The advent of deep sub-micron technology has recently highlighted the criticality of the on-chip interconnects. As diminishing feature sizes have led to increases in global wiring delays, network-on-chip (NoC) architectures are viewed as a possible solution to the wiring challenge and have recently crystallized into a significant research thrust. Both NoC performance and energy budget depend heavily on the routers' buffer resources. This paper introduces a novel unified buffer structure, called the dynamic virtual channel regulator (ViChaR), which dynamically allocates virtual channels (VC) and buffer resources according to network traffic conditions. ViChaR maximizes throughput by dispensing a variable number of VCs on demand. Simulation results using a cycle-accurate simulator show a performance increase of 25% on average over an equal-size generic router buffer, or similar performance using a 50% smaller buffer. ViChaR's ability to provide similar performance with half the buffer size of a generic router is of paramount importance, since this can yield total area and power savings of 30% and 34%, respectively, based on synthesized designs in 90 nm technology
2562587
Creating a Robust Desktop Grid using Peer-to-Peer Services
The goal of the work described in this paper is to design and build a scalable infrastructure for executing grid applications on a widely distributed set of resources. Such grid infrastructure must be decentralized, robust, highly available, and scalable, while efficiently mapping application instances to available resources in the system. However, current desktop grid computing platforms are typically based on a client-server architecture, which has inherent shortcomings with respect to robustness, reliability and scalability. Fortunately, these problems can be addressed through the capabilities promised by new techniques and approaches in peer-to-peer (P2P) systems. By employing P2P services, our system allows users to submit jobs to be run in the system and to run jobs submitted by other users on any resources available in the system, essentially allowing a group of users to form an ad-hoc set of shared resources. The initial target application areas for the desktop grid system are in astronomy and space science simulation and data analysis.
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.