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Publicações

Publicações por CRACS

2010

Specifying a Programming Exercises Evaluation Service on the e-Framework

Autores
Leal, JP; Queiros, R; Ferreira, D;

Publicação
ADVANCES IN WEB-BASED LEARNING-ICWL 2010

Abstract
The e-Framework is arguably the most prominent e-learning framework currently in use. For this reason it was selected as basis for modelling a programming exercises evaluation service. The purpose of this type of evaluator is to mark and grade exercises in computer programming courses and in programming contests. By exposing its functions as services a programming exercise evaluator is able to participate in business processes integrating different system types, such as Programming Contest Management Systems, Learning Management Systems, Integrated Development Environments and Learning Object Repositories. This paper formalizes the approaches to be used in the implementation of a programming exercise evaluator as a service on the e-Framework.

2010

Design of an extensible metadata editor based on RDF

Autores
Lea, JP; Queiros, R;

Publicação
Proceedings of the European Conference on Knowledge Management, ECKM

Abstract
The content of a Learning Object is frequently characterized by metadata from several standards, such as LOM, SCORM and QTI. Specialized domains require new application profiles that further complicate the task of editing the metadata of learning object since their data models are not supported by existing authoring tools. To cope with this problem we designed a metadata editor supporting multiple metadata languages, each with its own data model. It is assumed that the supported languages have an XML binding and we use RDF to create a common metadata representation, independent from the syntax of each metadata languages. The combined data model supported by the editor is defined as an ontology. Thus, the process of extending the editor to support a new metadata language is twofold: firstly, the conversion from the XML binding of the metadata language to RDF and vice-versa; secondly, the extension of the ontology to cover the new metadata model. In this paper we describe the general architecture of the editor, we explain how a typical metadata language for learning objects is represented as an ontology, and how this formalization captures all the data required to generate the graphical user interface of the editor.

2010

Modeling and planning collaboration using organizational constraints

Autores
Igler, M; Moura, P; Färber, M; Zeising, M; Jablonski, S;

Publicação
The 6th International Conference on Collaborative Computing: Networking, Applications and Worksharing, CollaborateCom 2010, Chicago, IL, USA, 9-12 October 2010

Abstract
Process management systems play an important role for today's information systems. They coordinate the work items among employees and ensure the correct execution of processes. In this paper we focus on the organizational perspective of process management systems. This perspective is responsible for assigning people together with their roles within business organizations to process execution. A key issue in integrating the organizational perspective into processes is the strategy for selecting people to execute work steps. This assignment is the basis for collaboration among the people of an organization within a process-based application. We implemented our approach in ESProNa, a Logtalk application running in SWI-Prolog extended with the Thea library providing direct and complete support for OWL2 ontologies. The use of these languages allows the definition of comprehensive organizational constraints. We will cover both, the definition of these constraints in the process model, and their interpretation by the process execution engine. Further we will show how the organizational perspective impacts the order of process execution, i. e. the way of collaboration between the assigned people decisively. © 2010 ICST.

2010

Towards a study of meta-predicate semantics

Autores
Moura, P;

Publicação
Joint Workshop on Implementation of Constraint Logic Programming Systems and Logic-based Methods in Programming Environments, CICLOPS-WLPE 2010

Abstract
We describe and compare design choices for meta-predicate semantics, as found in representative Prolog module systems and in Logtalk. We look at the consequences of these design choices from a pragmatic perspective, discussing explicit qualification semantics, com- putational reflection support, expressiveness of meta-predicate declara- tions, safety of meta-predicate definitions, portability of meta-predicate definitions, and meta-predicate performance. Our aim is to provide use- ful insight for debating meta-predicate semantics and portability issues based on actual implementations and common usage patterns.

2010

ESProNa: Constraint-Based Declarative Business Process Modeling

Autores
Igler, M; Moura, P; Zeising, M; Jablonski, S;

Publicação
2010 14TH IEEE INTERNATIONAL ENTERPRISE DISTRIBUTED OBJECT COMPUTING CONFERENCE WORKSHOPS (EDOCW 2010)

Abstract
In this paper we describe how declarative process modeling together with ontologies can be used to build complex clinical process models. Our approach supports the definition of functional, behavioral, organizational, data and operational process perspectives, resulting in an expressive and flexible modeling language. We use constraints for representing inter-process dependencies and constraint propagation for finding which processes are executable in user selected or given scenarios. Knowledge about the organizational perspective of a clinical ontology can be represented and imported from RDF files for interfacing with other applications. We implemented our approach in ESProNa, a Logtalk application running on SWI-Prolog extended with the CLP(FD) constraint library and the N3 parser Henry.

2010

Threads and or-parallelism unified

Autores
Costa, VS; Dutra, I; Rocha, R;

Publicação
THEORY AND PRACTICE OF LOGIC PROGRAMMING

Abstract
One of the main advantages of Logic Programming (LP) is that it provides an excellent framework for the parallel execution of programs. In this work we investigate novel techniques to efficiently exploit parallelism from real-world applications in low cost multi-core architectures. To achieve these goals, we revive and redesign the YapOr system to exploit or-parallelism based on a multi-threaded implementation. Our new approach takes full advantage of the state-of-the-art fast and optimized YAP Prolog engine and shares the underlying execution environment, scheduler and most of the data structures used to support YapOr's model. Initial experiments with our new approach consistently achieve almost linear speedups for most of the applications, proving itself as a good alternative for exploiting implicit parallelism in the currently available low cost multi-core architectures.

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