Approximative filtering of XML documents in a publish/subscribe system

Publish/subscribe systems filter published documents and inform their subscribers about documents matching their interests. Recent systems have focussed on documents or messages sent in XML format. Subscribers have to be familiar with the underlying XML format to create meaningful subscriptions. A service might support several providers with slightly differing formats, e.g., several publishers of books. This makes the definition of a successful subscription almost impossible. This paper proposes the use of an approximative language for subscriptions. We introduce the design of our ApproXFilter algorithm for approximative filtering in a publish/subscribe system. We present the results of our performance analysis of a prototypical implementation

Capturing personal health data from wearable sensors

Recently, there has been a significant growth in pervasive computing and ubiquitous sensing which strives to develop and deploy sensing technology all around us. We are also seeing the emergence of applications such as environmental and personal health monitoring to leverage data from a physical world. Most of the developments in this area have been concerned with either developing the sensing technologies, or the infrastructure (middleware) to gather this data and the issues which have been addressed include power consumption on the devices, security of data transmission, networking challenges in gathering and storing the data and fault tolerance in the event of network and/or device failure. Research is focusing on harvesting and managing data and providing query capabilities

SMOQE: A System for Providing Secure Access to XML

XML views have been widely used to enforce access control, support data integration, and speed up query answering. In many applications, e.g., XML security enforcement, it is prohibitively expensive to materialize and maintain a large number of views. Therefore, views are necessarily virtual. An immediate question then is how to answer queries on XML virtual views. A common approach is to rewrite a query on the view to an equivalent one on the underlying document, and evaluate the rewritten query. This is the approach used in the Secure MOdular Query Engine (SMOQE). The demo presents SMOQE, the first system to provide efficient support for answering queries over virtual and possibly recursively defined XML views. We demonstrate a set of novel techniques for the specification of views, the rewriting, evaluation and optimization of XML queries. Moreover, we provide insights into the internals of the engine by a set of visual tools. 1

Energy Efficient XPath Query Processing on Wireless XML Streaming Data

An energy efficient way of disseminating XML data to several mobile clients is broadcast. Information such as alert on emergencies, election results and sporting event results can be of interest to large number of mobile clients. Since eXtensible Markup Language (XML) is widely used for information exchange, wireless information services require an energy efficient XML data dissemination. XML Path (XPath) represents selective data required by mobile clients. XPath query processing involves two performance metrics, namely tune-in time and access time. In this paper, we propose a novel structure for streaming XML data called Path Stream Group Level (PSGL) node by exploiting the tree structure of XML document. It possesses various small indices such as level, child, sibling, attribute, text for selective download of XML data by mobile clients. It organizes data based on the level of XML document tree and groups XML elements with same XML path prefix to conserve battery power at mobile clients. Experimental results show that proposed method has reduced tune-in time when compared with existing approaches. Hence PSGL approach enhances performance with energy conservation for processing various types of XPath queries

XPath: Looking Forward

The location path language XPath is of particular importance for XML applications since it is a core component of many XML processing standards such as XSLT or XQuery. In this paper, based on axis symmetry of XPath, equivalences of XPath 1.0 location paths involving reverse axes, such as anc and prec, are established. These equivalences are used as rewriting rules in an algorithm for transforming location paths with reverse axes into equivalent reverse-axis-free ones. Location paths without reverse axes, as generated by the presented rewriting algorithm, enable efficient SAX-like streamed data processing of XPath

Boosting XML Filtering with a Scalable FPGA-based Architecture

The growing amount of XML encoded data exchanged over the Internet increases the importance of XML based publish-subscribe (pub-sub) and content based routing systems. The input in such systems typically consists of a stream of XML documents and a set of user subscriptions expressed as XML queries. The pub-sub system then filters the published documents and passes them to the subscribers. Pub-sub systems are characterized by very high input ratios, therefore the processing time is critical. In this paper we propose a "pure hardware" based solution, which utilizes XPath query blocks on FPGA to solve the filtering problem. By utilizing the high throughput that an FPGA provides for parallel processing, our approach achieves drastically better throughput than the existing software or mixed (hardware/software) architectures. The XPath queries (subscriptions) are translated to regular expressions which are then mapped to FPGA devices. By introducing stacks within the FPGA we are able to express and process a wide range of path queries very efficiently, on a scalable environment. Moreover, the fact that the parser and the filter processing are performed on the same FPGA chip, eliminates expensive communication costs (that a multi-core system would need) thus enabling very fast and efficient pipelining. Our experimental evaluation reveals more than one order of magnitude improvement compared to traditional pub/sub systems.Comment: CIDR 200

Knowledge Sharing and Business Matching in Advertising and Public Relations Services Using Semantic Peer Technology

We develop semantic peer network aiming at knowledge sharing and business matching for the domain of advertisement and public relations. We top up a knowledge-based layer upon the peer to peer network to make it knowledge base peer. The knowledge base consists of ontology for the application domain and domain instances. We develop user services for resource sharing and business matching based on the knowledge-based layer. A trust management mechanism is built into the knowledge-based layer for making trustable resource sharing and business match making. Also we develop an RDF-based streaming mechanism for automatically pushing newly matched information to appropriate nodes. We made experiment to test the performance of search for the prototype system. The result shows that the addition of knowledge-based layer upon the peer-to-peer network would not result in the decrease of performance. We also investigate future work after the prototype researc

Safe Data Sharing and Data Dissemination on Smart Devices

The erosion of trust put in traditional database servers, the growing interest for different forms of data dissemination and the concern for protecting children from suspicious Internet content are different factors that lead to move the access control from servers to clients. Several encryption schemes can be used to serve this purpose but all suffer from a static way of sharing data. In a precedent paper, we devised smarter client-based access control managers exploiting hardware security elements on client devices. The goal pursued is being able to evaluate dynamic and personalized access control rules on a ciphered XML input document, with the benefit of dissociating access rights from encryption. In this demonstration, we validate our solution using a real smart card platform and explain how we deal with the constraints usually met on hardware security elements (small memory and low throughput). Finally, we illustrate the generality of the approach and the easiness of its deployment through two different applications: a collaborative application and a parental control application on video streams

An Efficient Dynamic XML Data Broadcasting Method in Mobile Wireless Network Using XPATH Queries

Wireless mobile computing has become popular. Users communicate in the wireless mobile environment using their mobi le devices such as smart phones and laptops while they are moving. In previous system can support only static XML rendered from repositories. It is not efficient for dynamic broadcasting of XML data over the stream. Consider energy conservation of mobile clients when disseminating data in the wireless mobile environment, because they use mobile devices with limited battery - power. structure indexing, lineage encoding, selective tuning algorithms can be used to minimize computation costs and filtering time