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Publications

2009

Information systems services outsourcing reality in large Portuguese organisations

Authors
Varajao, J; Trigo, A; Figueiredo, N; Barroso, J; Bulas Cruz, J;

Publication
International Journal of Business Information Systems

Abstract
Outsourcing has become a major component of information technology strategy in many companies around the world. From the early 1990s to the present, the reality of sourcing has varied significantly, an example being the services that companies typically choose to transfer to external providers, which are now different from those of one or two decades ago. This paper discusses the results of a survey conducted to determine the current outsourcing status of information systems services in large Portuguese organisations, by identifying the services that companies keep inside their boundaries and services that companies outsource to vendors. It also presents a comparison of the results from this study with results from studies developed in other countries. These findings should be useful both for researchers, who can use it to study the outsourcing and information systems function evolution, and for practitioners, mainly vendors, who may use it to build up its offer in agreement with the buyers' needs and wishes. Copyright © 2009, Inderscience Publishers.

2009

Side scan Sonar Image Segmentation and Feature Extraction

Authors
Pinto, M; Ferreira, B; Matos, A; Cruz, N;

Publication
OCEANS 2009, VOLS 1-3

Abstract
This paper describes an algorithm to make the treatment, segmentation, skeleton and characteristics extraction from acoustic images obtained from a side scan sonar. The fundamental goal is to implement a system that endows a autonomous vehicle with the capacity to know its own distance to the marine bottom and to features located on the marine environment. This features extraction would improve vehicle navigation and allow it to navigate relative to features like an underwater piper on the sea floor or a vertical wall. This paper was made based on Imagenex Sport Scan (side scan sonar) whose function is the observation of environment. Also the autonomous surface vehicle (ASV) ZARCO was used to transport the side scan sonar. Both the vehicles belong to The OceansSys Group DEEC-FEUP. A communication interface between the ASV ZARCO, Imagenex Sport Scan, and a static laptop that allows the observation of sonar data in real time is also described in this paper. The algorithms and routines implemented were validated with real acoustic images acquired during a mission. Results from algorithms application and features extraction are shown in this paper.

2009

MobMaps: Towards a Shared Environment for Collaborative Social Activism

Authors
Gens, L; Paredes, H; Martins, P; Fonseca, B; Mor, Y; Morgado, L;

Publication
GROUPWARE-DESIGN: IMPLEMENTATION, AND USE, PROCEEDINGS

Abstract
Nowadays it is possible to disseminate information to the all world in real time using current communication tools supported mostly by the Internet. The work of several organizations reporting a multitude of problems that our society faces can be sustained by participatory platforms, which stimulate the collaboration of participants all over the world. In this paper we present a technological platform that provides a shared environment for collaborative social activism. We adapted the platform to a particular organization, Machsom Watch that reports human rights abuses in Israelis checkpoints. Finally we present some preliminary results obtained by ethnographic research using the developed platform.

2009

Video object matching across multiple independent views using local descriptors and adaptive learning

Authors
Teixeira, LF; Corte Real, L;

Publication
PATTERN RECOGNITION LETTERS

Abstract
Object detection and tracking is an essential preliminary task in event analysis systems (e.g. visual surveillance). Typically objects are extracted and tagged, forming representative tracks of their activity. Tagging is Usually performed by probabilistic data association, however, in systems capturing disjoint areas it is often not possible to establish such associations, as data may have been collected at different times OF in different locations. In this case, appearance matching is a valuable aid. We propose using bag-of-visterms, i.e. an histogram of quantized local feature descriptors, to represent and match tracked objects. This method has proven to be effective for object matching and classification in image retrieval applications, where descriptors can be extracted a priori. An important difference in event analysis systems is that relevant information is typically restricted to the foreground. Descriptors can, therefore, be extracted faster, approaching real-time requirements. Also, unlike image retrieval, objects can change over time and therefore their model needs to be updated Continuously. Incremental or adaptive learning is used to tackle this problem. Using independent tracks of 30 different persons, we show that the bag-of-visterms representation effectively discriminates visual object tracks and that it presents high resilience to incorrect object segmentation. Additionally, this methodology allows the construction of scalable object models that can be used to match tracks across independent views.

2009

Commitment and authentication systems

Authors
Pinto, A; Souto, A; Matos, A; Antunes, L;

Publication
DESIGNS CODES AND CRYPTOGRAPHY

Abstract
In the present paper, we answer a question raised in the paper Constructions and Bounds for Unconditionally Secure Non-Interactive Commitment Schemes, by Blundo et al., 2002, showing that there is a close relation between unconditionally secure commitment schemes and unconditionally secure authentication schemes, and that an unconditionally secure commitment scheme can be built from such an authentication scheme and an unconditionally secure cipher system. To investigate the opposite direction, we define optimal commitment systems and show that these must be resolvable design commitment schemes. Then, a proof is given that the resolvable design commitment schemes are a composition of an authentication system and a cipher system and the conclusion follows that this is the case for all optimal commitment systems. We also show how to build optimal schemes from transversal designs that are easy to build and can be more efficiently implemented than the proposal in the previously cited paper.

2009

Exhibition and interactive module on optical phenomena [Módulo expositivo e interactivo sobre fenómenos ópticos]

Authors
Dionisio, RP;

Publication
Actas da 4a Conferencia Iberica de Sistemas e Tecnologias de Informacao, CISTI 2009

Abstract

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