Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Publications

Publications by CSE

2011

Highly-Birefringent Photonic Bandgap Bragg Fiber Loop Mirror for Sensing Applications

Authors
Ferreira, MS; Baptista, JM; Roy, P; Jamier, R; Fevrier, S; Frazao, O;

Publication
21ST INTERNATIONAL CONFERENCE ON OPTICAL FIBER SENSORS

Abstract
A highly-birefringent photonic bandgap Bragg fiber loop mirror sensor is proposed. Thanks to the Bragg fiber geometry, one can observe the group birefringence and the bandgap fiber in the transfer function. The sensing head presented different sensitivities for strain and temperature measurements. Using the matrix method, both the physical parameters can be discriminated. It is important to highlight that this Bragg fiber presents sensitivity to temperature of similar to 5.75 nm/degrees C, for the group birefringence measurand.

2011

Integrating the LMS in Service Oriented eLearning Systems

Authors
Leal, JP; Queirós, R;

Publication
Int. J. Knowl. Soc. Res.

Abstract
Learning management systems are routinely used for presenting, solving and grading exercises with large classes. However, teachers are constrained to use questions with pre-defined answers, such as multiple-choice, to automatically correct the exercises of their students. Complex exercises cannot be evaluated automatically by the LMS and require the coordination of a set of heterogeneous systems. For instance, programming exercises require a specialized exercise resolution environment and automatic evaluation features, each provided by a different type of system. In this paper, the authors discuss an approach for the coordination of a network of eLearning systems supporting the resolution of exercises. The proposed approach is based on a pivot component embedded in the LMS and has two main roles: (1) provide an exercise resolution environment, and (2) coordinate communication between the LMS and other systems, exposing their functions as web services. The integration of the pivot component in the LMS relies on Learning Tools Interoperability (LTI). This paper presents an architecture to coordinate a network of eLearning systems and validate the proposed approach by creating such a network integrated with LMS from two different vendors.

2011

Integration of ePortfolios in Learning Management Systems

Authors
Queiros, R; Oliveira, L; Leal, JP; Moreira, F;

Publication
COMPUTATIONAL SCIENCE AND ITS APPLICATIONS - ICCSA 2011, PT V

Abstract
The LMS plays a decisive role in most eLearning environments. Although they integrate many useful tools for managing eLearning activities, they must also be effectively integrated with other specialized systems typically found in an educational environment such as Repositories of Learning Objects or ePortfolio Systems. Both types of systems evolved separately but in recent years the trend is to combine them, allowing the LMS to benefit from using the ePortfolio assessment features. This paper details the most common strategies for integrating an ePortfolio system into an LMS: the data, the API and the tool integration strategies. It presents a comparative study of strategies based on the technical skills, degree of coupling, security features, batch integration, development effort, status and standardization. This study is validated through the integration of two of the most representative systems on each category - respectively Mahara and Moodle.

2011

A comparative study on LMS interoperability

Authors
Leal, JP; Queiros, R;

Publication
Higher Education Institutions and Learning Management Systems: Adoption and Standardization

Abstract
A Learning Management System (LMS) plays an important role in any eLearning environment. Still, the LMS cannot afford to be isolated from other systems in an educational institution. Thus, the potential for interoperability is an important, although frequently overlooked, aspect of an LMS system. In this chapter we make a comparative study of the interoperability features of the most relevant LMS in use nowadays. We start by defining a comparison framework, with systems that are representative of the LMS universe, and interoperability facets that are representative of the type integration with other broad classes of eLearning systems. For each interoperability facet we categorize and identify the most representative remote systems, we present a comprehensive survey of existing standards and we illustrate with concrete integration scenarios. Finally, we draw some conclusions on the status of interoperability in LMS based on our study. © 2012, IGI Global.

2011

Advanced control and management functionalities for multi-microgrids

Authors
Madureira, AG; Pereira, JC; Gil, NJ; Pecas Lopes, JAP; Korres, GN; Hatziargyriou, ND;

Publication
EUROPEAN TRANSACTIONS ON ELECTRICAL POWER

Abstract
This paper addresses the extension of the microgrid concept, following a massive integration of these active cells in power distribution networks, by adopting a coordinated management strategy together with distributed generation units directly connected to the medium voltage distribution network. In order to achieve this, a technical and commercial management scheme must be developed for coordinated control of a distribution system with multi-microgrids, which should take into account the specific technical capabilities and characteristics of each type of generating source. In particular, tools for coordinated voltage support and frequency control, as well as for state estimation have been developed for this type of network. Concerning voltage support, a new methodology exploiting an optimization tool based on a meta-heuristic approach was developed. For state estimation, two approaches were considered: multi-microgrid state estimation and fuzzy state estimation. Regarding frequency control, the hierarchical structure of the multi-microgrid is exploited to deal with the transition to islanded operation and load following in islanded operation. All these tools have proved to be efficient in managing the multi-microgrid system in normal interconnected mode and, in case of the frequency control, in islanded operation. Copyright (C) 2010 John Wiley & Sons, Ltd.

2011

Modelling Text File Evaluation Processes

Authors
Leal, JP; Queiros, R;

Publication
NEW HORIZONS IN WEB-BASED LEARNING: ICWL 2010 WORKSHOPS

Abstract
Text file evaluation is an emergent topic in e-learning that responds to the shortcomings of the assessment based on questions with predefined answers. Questions with predefined answers are formalized in languages such as IMS Question & Test Interoperability Specification (QTI) and supported by many e-learning systems. Complex evaluation domains justify the development of specialized evaluators that participate in several business processes. The goal of this paper is to formalize the concept of a text file evaluation in the scope of the E-Framework a service oriented framework for development of e-learning systems maintained by a community of practice. The contribution includes an abstract service type and a service usage model. The former describes the generic capabilities of a text file evaluation service. The later is a business process involving a set of services such as repositories of learning objects and learning management systems.

  • 205
  • 220