Multi‐Resolution Information Transmission in Mobile Environments

Leong, Hong Va; Si, Antonio

doi:10.1155/2005/595629

Cited by 3 publications

(4 citation statements)

References 21 publications

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“…We would like to further study the performance via extensive simulated experiments, as well as the impact of data broadcast scheduling, based on different parameters and algorithms to reduce the expected delay [7]. We would also like to investigate the effect of multi-resolution data broadcast approach [8].…”

Section: Resultsmentioning

confidence: 99%

“…Contents in an XML database could be modeled as a huge XML document like a tree containing cross links with labels on the nodes [1,13]. In a collection of textual files, each file could be modeled as a document, many of which possess a hierarchical structure, consisting of sections, subsections, up to paragraphs [8]. The collection of documents can be clustered into related categories.…”

Section: Data and Query Modelmentioning

confidence: 99%

“…It then consolidates the queries and expands the query scopes to include more irrelevant information so as to confuse the adversary, equivalent to generating fake queries in the process. In our preliminary study, we focus on a tree-structured database, which could be an XML database [10] or a collection of structured text documents [8].…”

Section: Introductionmentioning

confidence: 99%

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Privacy enhancement in mobile data broadcasting environments

Leong

2010

Proceedings of the 4th International Conference on Uniquitous Information Management and Communication

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In mobile and wireless environments, clients will request for information by submitting queries to the server, which delivers the required data via point-to-point connection or broadcast channels. The broadcast paradigm possesses the advantage of scalability. However, the broadcast data is vulnerable to eavesdropping and the adversary may be able to associate the requested data items and hence the original query with a specific client, a form of privacy threat that we would like to protect against. In this paper, we propose to protect the privacy of queries generated by individual clients by allowing them to hide themselves behind other clients. We assume a possibly untrustworthy server and make use of a trustworthy anonymizer for the queries. At the query anonymizer, user queries are clustered and consolidated into subsuming queries, to obfuscate the queries from being recovered. The consolidated queries are then expanded to improve the obfuscation effect, making it harder for the adversary to deduce the original queries. We define various performance metrics on the query privacy, by studying the ability that the adversary could crack the client queries, and propose algorithms to obfuscate a collection of user queries.

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Section: Resultsmentioning

confidence: 99%

Section: Data and Query Modelmentioning

confidence: 99%

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Privacy enhancement in mobile data broadcasting environments

Leong

2010

Proceedings of the 4th International Conference on Uniquitous Information Management and Communication

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“…In a general context, the dissemination of multimedia information is a subject of active investigation within mobile systems. For example, in [21] progressive transmission of multi-resolution documents occurs so that the viewer can first view the relevance of the information before continuing with full transfer. To reduce the impact of low bandwidth capacity and delay over multi-hop connections, caching of data in the vicinity of an ad hoc node [6] is a promising approach.…”

Section: Related Researchmentioning

confidence: 99%

Robust Video Communication over an Urban VANET

Qadri

Altaf

Fleury

et al. 2010

Mobile Information Systems

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Video communication within a Vehicular Ad Hoc Network (VANET) has the potential to be of considerable benefit in an urban emergency, as it allows emergency vehicles approaching the scene to better understand the nature of the emergency. However, the lack of centralized routing and network resource management within a VANET is an impediment to video streaming. To overcome these problems the paper pioneers source-coding techniques for VANET video streaming. The paper firstly investigates two practical multiple-path schemes, Video Redundancy Coding (VRC) and the H.264/AVC codec's redundant frames. The VRC scheme is reinforced by gradual decoder refresh to improve the delivered video quality. Evaluation shows that multiple-path 'redundant frames' achieves acceptable video quality at some destinations, whereas VRC is insufficient. The paper also demonstrates a third source coding scheme, single-path streaming with Flexible Macroblock Ordering, which is also capable of delivery of reasonable quality video. Therefore, video communication between vehicles is indeed shown to be feasible in an urban emergency if the suitable source coding techniques are selected.

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Database Support for M-Commerce and L-Commerce

Leong

2009

Encyclopedia of Information Science and Technology, Second Edition

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M-commerce (mobile commerce) applications have evolved out of e-commerce (electronic commerce) applications, riding on recent advancement in wireless communication technologies. Exploiting the most unique aspect inherent in m-commerce, namely, the mobility of customers, l-commerce (location-dependent m-commerce) applications have played an increasingly important role in the class of m-commerce applications. All e-commerce, m-commerce, and l-commerce applications rely on the provision of information retrieval and processing capability. L-commerce applications further dictate the maintenance of customer and service location information. Various database systems are deployed as the information source and repository for these applications, backed by efficient indexing mechanisms, both on regular data and location-specific data. Bean (2003) gave a good report on supporting Web-based e-commerce with XML, which could be easily extended to m-commerce. An m-commerce framework, based on JINI/XML and a workflow engine, was defined by Shih and Shim (2002). Customers can receive m-commerce services through the use of mobile devices such as pocket PCs, PDAs, or even smart phones. These mobile devices together with their users are often modeled as mobile clients. There are three types of entities central to m-commerce and l-commerce applications: mobile device, wireless communication, and database. In this article, we focus our discussion on mobile-client enabled database servers, often referred to as mobile databases. Mobile databases maintain information for the underlying m-commerce and l-commerce applications in which mobile devices serve as the hardware platform interfacing with customers, connected through wireless communication. Location is a special kind of composite data ranging from a single point, a line, a poly-line, to a shape defining an area or a building. In general, locations are modeled as spatial objects. The location of a static point of interest, such as a shop, is maintained in a database supporting spatial features and operations, often a spatial database (Güting, 1994). The location of a moving object, like a mobile customer, needs to be maintained in a moving object database (Wolfson, Sistla, Xu, Zhou, & Chamberlain, 1999), a database that supports efficient retrieval and update of object locations. To enable l-commerce, both spatial databases and moving object databases need to support location-specific query processing from mobile clients and location updates they generated. The two major types of data access requirements for a mobile database are data dissemination and dedicated data access. Data dissemination is preferred, since it can serve a large client population in utilizing the high bandwidth downlink channel to broadcast information of common interest, such as stock quotations, traffic conditions, or special events. On the other hand, dedicated data access is conveyed through uplink channels with limited bandwidth. To disseminate database items effectively, the selected set of hot database items can be scheduled as a broadcast disk (Acharya, Alonso, Franklin, & Zdonik, 1995). Proper indexes can be built to facilitate access to broadcast database items (Imielinski & Badrinath, 1994). Redundancy can be included in data (Leong & Si, 1995) and index (Tan & Ooi, 1998) to combat the unreliability of wireless communication.

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Multi‐Resolution Information Transmission in Mobile Environments

Cited by 3 publications

References 21 publications

Privacy enhancement in mobile data broadcasting environments

Privacy enhancement in mobile data broadcasting environments

Robust Video Communication over an Urban VANET

Database Support for M-Commerce and L-Commerce

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