On Secure Workflow Decentralisation on the Internet

Decentralised workflow management systems are a new research area, where most work to-date has focused on the system's overall architecture. As little attention has been given to the security aspects in such systems, we follow a security driven approach, and consider, from the perspective of available security building blocks, how security can be implemented and what new opportunities are presented when empowering the decentralised environment with modern distributed security protocols. Our research is motivated by a more general question of how to combine the positive enablers that email exchange enjoys, with the general benefits of workflow systems, and more specifically with the benefits that can be introduced in a decentralised environment. This aims to equip email users with a set of tools to manage the semantics of a message exchange, contents, participants and their roles in the exchange in an environment that provides inherent assurances of security and privacy. This work is based on a survey of contemporary distributed security protocols, and considers how these protocols could be used in implementing a distributed workflow management system with decentralised control . We review a set of these protocols, focusing on the required message sequences in reviewing the protocols, and discuss how these security protocols provide the foundations for implementing core control-flow, data, and resource patterns in a distributed workflow environment

Automated generation of object summaries from relational databases: A novel keyword searching paradigm

Abstract — This paper introduces a novel keyword searching paradigm in Relational Databases (DBs), where the result of a search is a ranked set of Object Summaries (OSs). An OS summarizes all data held about a Data Subject (DS) in the Database. More precisely, it is a tree with a tuple containing the Keyword as a root and neighboring tuples as children. In contrast to traditional Relational Keyword Search (R-KwS), an OS comprises a more complete and therefore semantically meaningful set of information about the enquired DS. The proposed paradigm is based on two key concepts: Affinity and Importance. The system investigates and quantifies the Affinity of relations in order to automatically create OSs and OS Importance (Im(OS)) in order to rank them. Im(OS)s considers the weight (i.e. PageRank) of tuples, Affinity and size of OS. Experimental evaluation on TPC-H and Northwind DBs so far verifies the searching quality of the proposed paradigm. I

Ranking of object summaries

Abstract — A previously proposed Keyword Search paradigm produces, as a query result, a ranked list of Object Summaries (OSs); each OS summarizes all data held in a relational database about a particular Data Subject (DS). This paper further investigates the ranking of OSs and their tuples as to facilitate (1) the top-k ranking of OSs and also (2) the generation of partial size-l OSs (i.e. comprised of the l most important tuples). Therefore, a global Importance score for each tuple of the database (denoted as Im(t i)) is investigated and quantified. For this purpose, ValueRank (an extension of ObjectRank) is introduced which facilitates the estimation of scores for arbitrary databases (in contrast to PageRank-style techniques that are only effective on bibliographic databases). In addition, a variation of Combined functions are investigated for assigning an Importance score to an OS (denoted as Im(OS)) and a local Importance score of their tuples (denoted as Im(OS, ti)). Preliminary Experimental evaluation on DBLP and Northwind Databases is presented. I

The electronic laboratory journal: a collaborative and cooperative learning environment for web-based experimentation

Numerous tools have been developed for supporting the collaboration between students in education, tools that mainly include facilities for sharing documents and enabling discussions. However, these environments do not emphasize the use of facilities that sustain collaborative work in the framework of remote experimentation carried out by a group of students located at different places. The Electronic Laboratory Journal (eJournal) paradigm proposed in this paper is a collaborative and cooperative environment for Web-based experimentation in engineering education. The eJournal enhances the traditional laboratory journal, by providing a group of students with Web-based tools to collect, annotate, organize and share the data chunks necessary to complete their experimentation assignments. The data chunks, called fragments, may be composed of numerous objects of any format, such as text, images, graphics, manuscripts, measurement logs or experimental results. Fragments can be uploaded from local disks or imported from Web components. The eJournal also handles the submission of results to the educators and facilitates remote supervision, assistance and tutoring of the students. The eJournal paradigm is currently assessed at the School of Engineering, the École Polytechnique Fédérale de Lausanne (EPFL), in the framework of hands-on experimentation activities focusing on remote manipulation of real setups and Web-based simulation. This paper presents the eJournal environment, its application and its evaluation as an enabling Web-based application for flexible learning