5969110
An Efficient Encoding and Labeling for Dynamic XML Data
In order to efficiently determine structural relationships among XML elements and to avoid re-labeling for updates, much research about labeling schemes has been conducted, recently. However, a harmonic support of efficient query processing and updating has not been achieved. In this paper, we propose an efficient XML encoding and labeling scheme, called EXEL, which is a variant of the region numbering scheme using bit strings. In order to generate the ordinal and insert-friendly bit strings in EXEL, a novel binary encoding method is devised. Also, we devise a labeling scheme for a newly inserted node which incurs no re-labeling of pre-existing labels. These encoding and inserting methods are the bases of efficient query processing and the complete avoidance of re-labeling for updates. Moreover, EXEL supports all structural relationships in XPath and the relationships can be checked by SQL statements supported by an RDBMS. Finally, the experimental results show that EXEL provides fairly reasonable query processing performance while completely avoiding re-labeling for updates.
13302890
An Efficient and Scalable Management of Ontology
OWL is a recommended language for publishing and sharing ontologies on the Semantic Web. To manage the ontologies, several OWL data management systems have been proposed. However, the existing systems have limitations of the scalability and the reasoning. In this paper, we propose an OWL data management system, ONTOMS, which stores OWL data into class based relations, performs complete inverseOf, symmetric, and transitive reasoning for instances, and efficiently evaluates OWL-QL queries against ontologies in a relational database.
14238943
Secure query processing against encrypted XML data using Query-Aware Decryption
Dissemination of XML data on the internet could breach the privacy of data providers unless access to the disseminated XML data is carefully controlled. Recently, the methods using encryption have been proposed for such access control. However, in these methods, the performance of processing queries has not been addressed. A query processor cannot identify the contents of encrypted XML data unless the data are decrypted. This limitation incurs overhead of decrypting the parts of the XML data that would not contribute to the query result. In this paper, we propose the notion of Query-Aware Decryption for efficient processing of queries against encrypted XML data. Query-Aware Decryption allows us to decrypt only those parts that would contribute to the query result. For this purpose, we disseminate an encrypted XML index along with the encrypted XML data. This index, when decrypted, informs us where the query results are located in the encrypted XML data, thus preventing unnecessary decryption for other parts of the data. Since the size of this index is much smaller than that of the encrypted XML data, the cost of decrypting this index is negligible compared with that for unnecessary decryption of the data itself. The experimental results show that our method improves the performance of query processing by up to six times compared with those of existing methods. Finally, we formally prove that dissemination of the encrypted XML index does not compromise security.
6394953
Accelerating Database Processing at e-Commerce Sites
Most e-commerce Web sites dynamically generate their contents through a three-tier server architecture composed of a Web server, an application server, and a database server. In such an architecture, the database server easily becomes a bottleneck to the overall performance. In this paper, we propose WDBAccel, a high-performance database server accelerator that significantly improves the throughput of the database processing, and thus that of the overall Web site. WDBAccel eliminates costly, complex query processing needed to obtain query results by reusing previous query results for subsequent queries. This differentiates WDBAccel from other database cache systems, which replicate a database into multiple conventional DBMS’s and distribute queries among them. We evaluate the performance of WDBAccel by using the queries of the TPC-W benchmark. The measurement results show that WDBAccel outperforms DBMS-based cache systems by up to an order of magnitude.
1141580
The evolution of outsourcing research: what is the next issue?
Although many researchers and practitioners have discussed different aspects of outsourcing in the past, there have been only a handful of papers that grapple these complex issues from a broad perspective. The main purpose of this study is to lay an integrative groundwork for the understanding of outsourcing, including its key research areas, its evolution, its theoretical models, and its future research trend. From our review of the past studies, we identify the key research areas and their evolution that help to provide a deeper understanding on the outsourcing trend. Essentially, we propose that the previous research can be represented in two stages: the first stage based on clients' view, hierarchical relationship, and win-lose strategy; the second stage based on both the clients and the service providers' views, equal relationship, and win-win strategy. From this classification, we introduce an integrative perspective that focuses on both stages as a way to understand the emergence of partnership-based outsourcing. The critical outsourcing issues and the integrative theoretical perspective presented in this study may provide new insights in the direction and focus of future outsourcing research.
45872187
Parallel Programming with Polaris
Parallel programming tools are limited, making effective parallel programming difficult and cumbersome. Compilers that translate conventional sequential programs into parallel form would liberate programmers from the complexities of explicit, machine oriented parallel programming. The paper discusses parallel programming with Polaris, an experimental translator of conventional Fortran programs that target machines such as the Cray T3D.
6606959
Adaptively Mapping Code in an Intelligent Memory Architecture
This paper presents an algorithm to authomatically map code to a generic Processor-In-Memory (PIM) system that consists of a host processor and a much simpler memory processor. To achieve high performance with this type of architecture, code needs to be partitioned and scheduled such that each section is assigned to the processor on which it runs most efficiently. In addition, processors should overlap their execution as much as possible. 
 
Our algorithm is embeded in a compiler and run-time system and maps applications fully automatically using both static and dynamic information. Using a set of applications and a simulated architecture, we show average speedups of 1.7 over a single host with plain memory. The speedups are very close and often higher than ideal speedups on a more expensive multiprocessor system composed of two identical host processors. Our work shows that heterogeneity can be cost-effectively exploited, and represents one step toward effectively mapping code to more advanced PIM systems.