Time cost evaluation of trust based access control for XML databases

XML databases are widely used in many different areas. They are multi user systems and can store a huge amount of data. Sensitive and important data need to be protected and stored securely. We have developed a dynamic trust based access control for XML databases to improve the security level and prevent malicious transactions from both internal and external users. Our system tracks user history of errors and bad transactions and updates the access privileges depending on trust values. In this paper, we evaluate the use of trust based access control by measuring the real time cost. The experimental work is performed to test the access time with and without trust based access control and suggests that the approach, though costly is not prohibitively time consuming

Structurally Tractable Uncertain Data

Many data management applications must deal with data which is uncertain, incomplete, or noisy. However, on existing uncertain data representations, we cannot tractably perform the important query evaluation tasks of determining query possibility, certainty, or probability: these problems are hard on arbitrary uncertain input instances. We thus ask whether we could restrict the structure of uncertain data so as to guarantee the tractability of exact query evaluation. We present our tractability results for tree and tree-like uncertain data, and a vision for probabilistic rule reasoning. We also study uncertainty about order, proposing a suitable representation, and study uncertain data conditioned by additional observations.Comment: 11 pages, 1 figure, 1 table. To appear in SIGMOD/PODS PhD Symposium 201

Twelve Theses on Reactive Rules for the Web

Reactivity, the ability to detect and react to events, is an essential functionality in many information systems. In particular, Web systems such as online marketplaces, adaptive (e.g., recommender) systems, and Web services, react to events such as Web page updates or data posted to a server. This article investigates issues of relevance in designing high-level programming languages dedicated to reactivity on the Web. It presents twelve theses on features desirable for a language of reactive rules tuned to programming Web and Semantic Web applications

Integrated Solution Support System for Water Management

Solving water management problems involves technical, social, economic, political and legal challenges and thus requires an integrated approach involving people from different backgrounds and roles. The integrated approach has been given a prominent role within the European Union¿s Water Framework Directive (WFD). The WFD requires an integrated approach in water management to achieve good ecological status of all water bodies. It consists amongst others of the following main planning stages: describing objectives, assessing present state, identifying gaps between objectives and present state, developing management plan, implementing measures and evaluating their impacts. The directive prescribes broad participation and consultation to achieve its objectives. Besides the obvious desktop software, such an integrated approach can benefit from using a variety of support tools. In addition to tools for specific tasks such as numerical models and questionnaires, knowledge bases on options and process support tools may be utilized. Water stress, defined as the lack of water of appropriate quality is one issue related to, but not specifically addressed by the WFD. However, like in the WFD, a participatory approach could be used to mitigate water stress. Similarly various tools can or need to be used in such a complex process. In the AquaStress Integrated project the Integrated Solution Support System (I3S ¿ I-triple-S) is developed. One of the cornerstones of the approach taken in AquaStress is that organizing available knowledge provides sufficient information to improve the possibility to make a water stress mitigation process truly end-user driven, meaning that dedicated local information is only collected after specific need is expressed by the stakeholders in the process. The novelty of the I3S lies in the combination of such knowledge stored in knowledge-bases, with adaptable workflow management facilities and with specific task-oriented tools ¿ all originating from different sources. This paper describes the I3S

Supporting the clinical trial recruitment process through the grid

Patient recruitment for clinical trials and studies is a large-scale task. To test a given drug for example, it is desirable that as large a pool of suitable candidates is used as possible to support reliable assessment of often moderate effects of the drugs. To make such a recruitment campaign successful, it is necessary to efficiently target the petitioning of these potential subjects. Because of the necessarily large numbers involved in such campaigns, this is a problem that naturally lends itself to the paradigm of Grid technology. However the accumulation and linkage of data sets across clinical domain boundaries poses challenges due to the sensitivity of the data involved that are atypical of other Grid domains. This includes handling the privacy and integrity of data, and importantly the process by which data can be collected and used, and ensuring for example that patient involvement and consent is dealt with appropriately throughout the clinical trials process. This paper describes a Grid infrastructure developed as part of the MRC funded VOTES project (Virtual Organisations for Trials and Epidemiological Studies) at the National e-Science Centre in Glasgow that supports these processes and the different security requirements specific to this domain