6251517
A Front-End Approach for User Query Generation and Information Retrieval in the SemanticLIFE Framework
Formulating unambiguous queries in the Semantic Web applications is a challenging task for users. This paper presents a new approach in guiding users to generate clear requests based on their common nature of querying for information. The approach known as the "front-end approach" gives users an overview about the system data through a "virtual data component" which stores the extracted metadata of the data storage sources in the form of an ontology. This approach reduces the ambiguities in users' requests at very early stage; and allows the query refinement process to easily to fulfill users's demands. Furthermore, the approach provide a powerful query engine, called "context-based querying", that recommends the appropriate query patterns according to the user's querying context. These features help the user in generating clear query more easier.
7825329
Zero-Latency Data Warehousing for Heterogeneous Data Sources and Continuous Data Streams
In this paper, a framework for building an overall Zero-Latency Data Warehouse system (ZLDWH) is provided. Such a ZLDWH requires tasks such as data changes detection, continuous loading and updating of new data, autonomous analysis and the execution of actions to be completed in the Data Warehouse (DWH). For this purpose, we combine (1) an existing solution for the continuous data integration and (2) the known approach of Active Data Warehousing (ADWH) by introducing protocols that enable the correct collaboration between the two. The continuous data integration is realized on the one hand by asynchronous communication between multiple information sources and the DWH through a message queuing system, and on the other hand by the continuous loading and updating. To obtain a low-latency time for this cycle, an “active rule evaluation” is provided between the data feeding stage and its loading into the DWH. This is realized by applying ECA-Techniques (EventCondition-Action) to obtain a more “active” characteristic of the DWH. A second goal of this paper is to take into consideration a special class of information source namely continuous data streams. Continuous data streams are information sources in which data arrives in high-volume, rapidly, bursty, and needs to be processed continuously. Therefore novel protocols and techniques are needed for capturing, storing and evaluate analysis decision based on new coming data from such continuous data stream sources.
37264651
Rough Set Approach to Sunspot Classification Problem
This paper presents an application of hierarchical learning method based rough set theory to the problem of sunspot classification from satellite images. The Modified Zurich classification scheme [3] is defined by a set of rules containing many complicated and unprecise concepts, which cannot be determined directly from solar images. The idea is to represent the domain knowledge by an ontology of concepts – a treelike structure that describes the relationship between the target concepts, intermediate concepts and attributes. We show that such ontology can be constructed by a decision tree algorithm and demonstrate the proposed method on the data set containing sunspot extracted from satellite images of solar disk.
534199
GRAVY: Towards Virtual File System for the Grid
Today large-scale applications require access to data stored in heterogeneous storage systems located at geographically distributed virtual organizations. In such applications, users are forced to deal with different administrative policies and structures at each site, and various data access mechanisms on each storage system. This implies a lot of human interventions in order to develop dedicated programs and scripts for data transfer between theses systems. This paper presents GRid-enAbled Virtual file sYstem (GRAVY) architecture which enables the automation of data transfers between distributed file systems irrespective of their heterogeneity. This feature enables high-level schedulers integrated with GRAVY to control data placements like computational jobs. GRAVY supports multiple data access protocols and provides an easy-to-use interface for novice Grid users.
15987233
Two-phase perspective ray casting for interactive volume navigation
Volume navigation is the interactive exploration of volume data sets by "flying" the view point through the data, producing a volume rendered view at each frame. The authors present an inexpensive perspective volume navigation method designed to run on a PC platform with accelerated 3D graphics hardware. They compute perspective projections at each frame, allow trilinear interpolation of sample points, and render both gray scale and RGB volumes by volumetric compositing. The implementation handles arbitrarily large volumes, by dynamically swapping data within the local depth-limited frustum into main memory as the viewpoint moves through the volume. They describe a new ray casting algorithm that takes advantage of the coherence inherent in adjacent frames to generate a sequence of approximate animated frames much faster than they could be computed individually. They also take advantage of the 3D graphics acceleration hardware to offload much of the alpha blending and resampling from the CPU.
8388633
Integration of quantum cryptography in 802.11 networks
Quantum cryptography is considered as a promising solution towards absolute security in long-term cryptosystems. While the application of quantum cryptography in fiber networks has significant advances, research on the application of quantum cryptography in mobile networks is still premature. In this paper, we analyze the interests of using quantum technique for the distribution of encryption keys in 802.11 wireless networks. We also propose a scheme for the integration of quantum cryptography in 802.11i security mechanisms for the establishment of the PTK (pairwise transient key).
18341353
Alias verification for Fortran code optimization
Abstract Alias analysis for Fortran is less complicated than for programming languages with pointers but many real Fortran programs violate the standard: a formal parameter or a common variable that is aliased with another formal parameter is modified. Compilers, assuming standard-conforming programs, consider that an assignment to one variable will not change the value of any other variable, allowing optimizations involving the aliased variables. Higher performance results but anything may happen: the program may appear to run normally, or may produce incorrect answers, or may behave unpredictably. The results may depend on the compiler and the optimization level. To guarantee the standard conformance of programs and to maintain the referential transparency in order to make program analyses exact and program optimizations safe, precise alias information retrieval at a reasonable cost, especially the determination of overlaps between arrays are studied in this paper. Static analyses and code instrumentation are used to find all violations of the prohibitions against aliasing in Fortran code. Alias violation tests are inserted only at places where it cannot be proved statically that they are useless in order to reduce the number of dynamic checks at run-time. A specific memory location naming technique is used to compact representation and enhance the precision of alias analysis. Modifications on the dependence graph created by aliasing are also studied to show the impact of aliases on some program optimizing transformations. Experimental results on SPEC95 benchmark are presented and some related issues are also discussed.