5328327
Fault-tolerant parallel applications using queues and actions
There are many techniques supporting execution of large computations over a network of workstations (NOW) but data intensive computations are usually run on high performance parallel machines. A NOW comprising individual user's machines typically has a low performance interconnect and suffers arbitrary changes of availability. Exploiting such resources to execute data intensive computations is difficult but even in a more constrained environment there is an unfulfilled need for fault-tolerance. The structuring approach presented fulfills this need. Performance exceeding 100 Mflop/s is demonstrated for large fault-tolerant out of core examples of matrix multiplication and Cholesky factorisation using five 133 MHz Pentium compute machines.
8773742
On Synchronisation in Fault-Tolerant Data and Compute Intensive Programs over a Network of Workstations
An application structured as a fault-tolerant bag of tasks adapts easily to changing resources. To be represented by a single bag of tasks, a computation must decompose into purely independent tasks. The work summarised here investigates performance of structuring approaches applicable where this ideal is not possible, partly through analysis and partly through measurements of a realistic fault-tolerant computation.
16226748
Polar: an architecture for a parallel ODMG compliant object database
Object database management systems (ODBMS) are now established as the database management technology of choice for a range of challenging data intensiv e applications. Furthermore, the applications associated with object databases typically have stringen t performance requirements, and some are associated with very large data sets. Ho w ever, despite the demands made on object databases by applications, there has been surprisingly little work on parallel object databases. This paper presents the arc hitecture and some preliminary performance results for the Polar ODMG compliant parallel object database. The architecture described has been implemented in a shared-nothing environment on a network of PCs. The paper describes how OQL queries are compiled, parallelized and executed in this environment, and includes some preliminary performance results for OQL queries using the 007 benchmark.
13121681
A parallel algebra for object databases
The paper describes an algebra for use with parallel object databases, and in particular ODMG compliant databases with OQL. Although there have been many proposals for parallel relational database systems, there has been much less work on parallel object databases, and on parallel query processing for object databases. The parallel algebra presented in the paper is an extension of an existing physical algebra for OQL, and has an important role during query optimization, and for describing execution plans. The paper presents not only the algebra, but also its role in the architecture of a parallel database.
15945659
Distributed Query Processing on the Grid
Distributed query processing (DQP) has been widely used in data intensive applications where data of relevance to users is stored in multiple locations. This paper argues: (i) that DQP can be important in the Grid, as a means of providing high-level, declarative languages for integrating data access and analysis; and (ii) that the Grid provides resource management facilities that are useful to developers of DQP systems. As well as discussing and illustrating how DQP technologies can be deployed within the Grid, the paper describes a prototype implementation of a DQP system running over Globus.
16693115
An Experimental Performance Evaluation of Join Algorithms for Parallel Object Databases
Parallel relational databases have been successful in providing scalable performance for data intensive applications, and much work has been carried out on query processing techniques in such systems. However, although many applications associated with object databases also have stringent performance requirements, there has been much less work investigating parallel object database systems. An important feature for the performance of object databases is the speed at which relationships can be explored. In queries, this depends upon the effectiveness of different join algorithms into which queries that follow relationships can be compiled. This paper presents the results of empirical evaluations of four parallel join algorithms, two value based and two pointer based. The experiments have been run on Polar, a parallel ODMG object database system.
17817110
MPEG-7 video automatic labeling system
In this demo, we show a novel end-to-end video automatic labeling system, which accepts MPEG-1 sequence inputs and generates MPEG-7 XML metadata files. Detections are based on the prior established anchor models. This system has two parts: model training process and labeling process. They are comprised of seven modules: Shot Segmentation, Region Segmentation, Annotation, Feature Extraction, Model Learning, Classification, and XML Rendering.
45728102
Causal Identification in Design Networks
When planning and designing a policy intervention and evaluation, the policy maker will have to define a strategy which will define the (conditional independence) structure of the available data. Here, Dawid’s extended influence diagrams are augmented by including ‘experimental design’ decisions nodes within the set of intervention strategies to provide semantics to discuss how a ‘design’ decision strategy (such as randomisation) might assist the systematic identification of intervention causal effects. By introducing design decision nodes into the framework, the experimental design underlying the data available is made explicit. We show how influence diagrams might be used to discuss the efficacy of different designs and conditions under which one can identify ‘causal’ effects of a future policy intervention. The approach of this paper lies primarily within probabilistic decision theory.
577324
Exploring image functionalities in WWW applications development of image/video search and editing engines
Image technologies provide critical components for achieving various Web-based multimedia applications. We identify key technical challenges in today's image/video applications on the WWW. We present two prototype systems, a video search engine (WebSEEk) and a compressed video editor (WebClip), to demonstrate technical challenges and viable solutions. We also discuss major issues in developing next-generation, scalable solutions for large-scale, distributed on-line environments.
38193465
Modeling semantic concepts to support query by keywords in video
Supporting semantic queries is a challenging problem in video retrieval. We propose the use of a lexicon of semantic concepts for handling the queries. We also propose automatic modeling of lexicon items using probabilistic techniques. We use Gaussian mixture models to build computational representations for a variety of semantic concepts including rocket-launch, outdoor greenery, sky etc. Training requires a large amount of annotated (labeled) data. Using the TREC Video test bed we compare the performance of this system supporting query by keywords with the conventional approach of query by example. Results demonstrate significant gains in performance using the automatically learnt models of semantic concepts.
2339969
Interactive search fusion methods for video database retrieval
In this paper, we investigate a new method for video database retrieval using interactive search fusion. Recent video analysis techniques have enabled the extraction of a variety of descriptors of features, concepts, clusters, classification results, speech and textual terms, MPEG-7 metadata, and so on. However, given an information need users are faced with a daunting task of trying to formulate queries over these multiple disparate data sources in order to retrieve the desired video content. In this paper, we explore a novel approach based on search fusion in which the user interactively builds a query by sequentially choosing among the descriptors and data sources and by selecting from various combining and score aggregation functions to fuse results of individual searches. For example, the system allows building of queries such as "retrieve video clips that have color of beach scenes, the detection of sky, and detection of water". In this paper we present the search fusion method and evaluate the performance on a large video database.