Publications

We formally capture the notion of a virtual enterprise - a rapidly configured and continuously reconfiguring collection of enterprises acting together to produce specific products. In a sequence of formally justified refinements and using the trader concept of the emerging ODP (Open Distributed Processing) standard, we make the model increasingly flexible and dynamic. For each step we show that up to some internal details, the resulting models implement the initial enterprise model. As the formal notation we use RSL, the RAISE specification language. The outcome of this paper can be used, we believe, to provide architectural foundations for studying more concrete concepts, like development of information infrastructures, in enterprise integration.

Traditional methods of dental surgical skills training and assessment are being challenged by complications such as unavailability of expert supervision and the subjective manner of surgical skills assessment. This paper presents a dental surgical skills training system that provides a virtual reality environment with a haptic device for dental students to practice tooth preparation procedures. The system monitors important features of the procedures, objectively assesses the quality of the performed procedure and provides objective feedback on the user’s performance for each stage in the procedure. We evaluated the accuracy of the skill assessment with data collected from novice dental students as well as experienced dentists. The experimental results show high accuracy in classifying users into novice and expert. The evaluation of the system’s generated feedback also indicated a high acceptance rate.

A recent feature of Electronic Governance programs is the adoption of Whole-of-Government (WG) approach to planning, design, delivery and operation of Information Technology (IT) - related initiatives. The approach is characterized by the integrated and coordinated pursuit by government agencies of shared objectives concerning service delivery, citizen engagement, public policy development, and others. Adopting a WG approach requires a clear understanding of the coordination needs and the dominant organizational culture of the agencies involved.

Parallel corpora are resources used in Natural Language Processing and Computational Linguistics. They are defined as a set of texts, in different languages, that are translations of each other. Note that these translations do not need to cover the full document, as we might have sentences translated just on some of the languages. When dealing with the process of sharing resources, recent years have bet on the use of XML formats. This is no different when talking about parallel corpora sharing. When visiting different projects in the web that release parallel corpora for download, we can find at least three different formats. In fact, this abundance of formats has led some projects to adopt all the three formats. This article discusses these three main formats: XML Corpus Encoding Standard, Translation Memory Exchange format and the Text Encoding Initiative. We will compare their formal definition and their XML schema.

This study analyzes the benefits and limitations of a “free-selection” peer assignment protocol by comparing them to the widely implemented “assigned-pair” protocol. The primary motivation was to circumvent the issues that often appear to the instructors implementing peer review activities with pre-assigned groups, without posing additional workload to the instructor or diminishing the learning outcomes. In the study, 36 sophomore students in a Computer Networking course were randomly assigned into two conditions: 20 in Assigned-Pair, where the students worked in pre-defined dyad, and 17 in Free-Selection, where students were able to explore and select peer work for review. Result analysis showed a very strong tendency in favor of the Free-Selection students regarding both domain specific (conceptual) and domain-general (reviewing) knowledge.

This work analyzes a case of computer-supported scripted collaboration, focusing on how students’ self-organization affected the actual collaboration script during script run-time. Two groups of students studied learning material using a web environment designed for supporting case-based learning. The first group followed a non-scaffolded individual mode of study while students in the second group were guided by a collaboration script to work (in dyads) on the case material. Statistical analysis indicated no significant differences in the learning outcomes of the two groups. Qualitative analysis (based on students’ interviews and field observations) revealed that students’ self-organization resulted to a broad range of actual script implementation ranging from full conformance to partial violation of the script guidelines. The paper discusses the socio-cognitive role of students’ self-organization during scripted collaboration and presents suggestions for the teacher and CSCL designer in order to enhance the engagement of collaborating students to productive learning interactions.

The focus of this paper is on reducing the complexity in verification by exploiting modularity at various levels: in specification, in verification, and structurally. For specifications, we use the modular language CSP-OZ-DC, which allows us to decouple verification tasks concerning data from those concerning durations. At the verification level, we exploit modularity in theorem proving for rich data structures and use this for invariant checking. At the structural level, we analyze possibilities for modular verification of systems consisting of various components which interact. We illustrate these ideas by automatically verifying safety properties of a case study from the European Train Control System standard, which extends previous examples by comprising a complex track topology with lists of track segments and trains with different routes.

Supporting students' awareness of the complex way that contextual issues affect knowledge application in authentic situations is a critical instructional mission and can lead to improved problem solving in the workplace. In this work we present the design of e-CASE (Context Awareness Supporting Environment), which is a case based learning environment for supporting instruction in the domain of software development. In designing e-CASE we employ a model for context which further guides the use of script and narrative control techniques as external representations for enhancing students' context awareness. Our system applies an appropriate metadata scheme for connecting various pieces of information and creating crossing paths for the learner, in the web of authentic application cases. It also provides functionality for updating and extending its content allowing people from the workplace to become content providers. Thus, we argue, e-CASE can help bridging the contextual distance, supporting the development of an extended learning community by establishing flexible and instructionally efficient links between the traditional educational settings and the workplace.

The success of the electronic governance (EGOV) benchmarking has been limited so far. Lacking a theory to integrate existing conceptualizations has made the acquisition and sharing of knowledge produced by different benchmarking exercises difficult. In order to address this problem, this paper: 1) explains the nature of the EGOV benchmarking activity though a well-established theoretical framework - Activity Theory, 2) applies the framework to carry out a mapping between a number of existing EGOV benchmarking conceptualizations, 3) develops an unified conceptualization based on these mappings and 4) validates the resulting model though a real-life national EGOV strategy development project. The use of the Activity Theory in the paper has enabled defining and relating initial dimensions of the EGOV benchmarking activity, and mapping the dimensions present in existing conceptualizations. This not only created a unifying theoretical basis for conceptualizing the EGOV benchmarking activity but allowed learning from and integrating existing conceptualizations. The work impacts on the EGOV benchmarking practice by enabling a logical design of the activity, and contextually correct understanding of existing EGOV benchmarking results with respect to their intended usage.

 A reactive system does not terminate and its behaviors are typically defined as a set of infinite sequences of states. In formal verification, a requirement is usually expressed in a logic, and when the models of the logic are also defined as infinite sequences, such as the case for LTL, the satisfaction relation is simply defined by the containment between the set of system behaviors and that of logic models. However, this satisfaction relation does not work for interval temporal logics, where the models can be considered as a set of finite sequences. In this paper, we observe that for different interval based properties, different satisfaction relations are sensible. Two classes of properties are discussed, and accordingly two satisfaction relations are defined, and they are subsequently unified by a more general definition. A tool is developed based on the Spin model checking system to verify the proposed general satisfaction relation for a decidable ubset of Discrete Time Duration Calculus. Keywords: model checking, finitary property, reactive system, interval temporal logic

We present a model for component software. We describe how components are specified at the interface level, design level and how they are composed. From its external view, a component consists a set of interfaces, provided to or required from its environment. From its internal view, a component is an executable code that can be coupled with other components via its interfaces. The developer has to ensure that the specification of a component is met by its design and implementation. We also combine component-based and object-oriented techniques in component-based software development This report is a refined version of UNU-IIST Report 276 and is to be presented at and published in the proceedings IFIP WCC-TCS2004, 24-26 August 2004, Toulouse, France.

We propose a new methodology to discover the relationship between authors and research domains. The methodology utilizes the classic author-topic model to find the probabilistic relationships among authors, topics and papers. A distance matrix is used to find authors close to the authors obtained from the classic author-topic model for a given topic. In addition, the relationship of selected authors is examined with a co-authorship network model. We compare the performance of our methodology with that of the classic author-topic model. The experimental results on the DBLP database show that the proposed methodology discovers more precise relationships between authors and research domains than does the classic author-topic model, with a 36% increase in performance.