Ciências e Tecnologia | Capítulos/artigos em livros internacionais / Book chapters/papers in international books
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- A distributed environment to support cooperative software developmentPublication . Marcos, AdéritoCooperative environments to support Software Development (CSD) have as main goal to enable several users connected over network to work together in order to develop software. They have to solve problems such as: coherence maintenance of the software project through the distributed system by managing possible conflicts between local versions of each group member and promote the necessary mechanisms for the inter-group awareness and integrity. We introduce in this paper a distributed solution to support CSD by describing our own prototype: a Computer-Supported Cooperative Work (CSCW) architecture for software development. It enables a group of developers (2 to 4), possibly located at remote places and connected over network, to develop software together. A cooperative multimedia editing environment is available during the development cycle, enclosing mechanisms of computer-conferencing (text, audio and video communications).
- Computer graphics as an enabling technology for cooperative, global applicationsPublication . Marcos, Adérito; Chesnais, Alain; Encarnação, JoséIn this article I would like to highlight one of the research and technological areas receiving considerable influence from CG technology, namely the computer-supported cooperative work (CSCW) environments. A report on some representative projects and applications in this area is also presented.
- Multimedia technology and 3D environments used in the preservation and dissemination of the portuguese cultural heritagePublication . Marcos, Adérito; Bernardes, Paulo; Sá, VítorCultural heritage is an extremely valuable set of materiality, traditions and knowledge from the Past that should be used to better understand the Past itself. However, even nowadays there are still some difficulties to manage, preserve and disseminate cultural heritage sites. The usage of multimedia technology and 3D environments in cultural heritage has reduced these difficulties; nonetheless, there are still some remaining problems. In the last years, some multimedia technology and 3D environments have been applied to the cultural heritage in Portugal. A few of them are used for scientific research purposes and others are used for dissemination purposes. In this article, the authors will refer to some representative Portuguese case studies using Virtual Environments to maintain, preserve and promote Cultural Heritage. A critical reading of these projects will be made in order to stress out their success and to point out their weaknesses and limitations.
- Supporting information visualization through topic mapsPublication . Marcos, Adérito; Oliveira, Alexandre Rocha; Malgueiro, Octávio; Grave, LuísWe are living a phenomenon of accelerated information production with different accessing sources. Hence users are faced with a growing problem: accessing (navigation) and filtering specific information contained in large datasets, which are increasing in size. Procedures such as data filtering and gathering are now simplified through a new concept known as Topic Maps. The application of Virtual Reality technologies enables to present and interact with multidimensional information in a 3D space. In this paper we present INSPHERE, a new visual metaphor for information visualization,based on both, Virtual Reality techniques, and “geographical information maps” provided by Topic Maps.
- ARK: augmented reality kioskPublication . Pereira, Pedro; Matos, Nuno; Marcos, AdéritoThis paper aims at presenting a very first prototype of an Augmented Reality (AR) system that as been developed in recent months at our research group. The prototype adopts a kiosk format and allows users to directly interact with an AR environment using a conventional data glove. The most relevant feature of this environment is the use of a common monitor to display AR images, instead of employing specific Head-Mounted Displays. By integrating a half-silvered mirror and a black virtual hand, our solution solves the occlusion problem that normally occurs when a user interacts with a virtual environment displayed by a monitor or other projection system.
- The crew timetabling problem: an extension of the crew scheduling problemPublication . Gomes, Marta Castilho; Cavique, Luís; Themido, IsabelIn some urban transportation companies driving periods are short when compared with the total duty time, leading to long non-driving periods that can be used as cover time. This paper presents the Crew Timetabling Problem, an extension of the Crew Scheduling Problem in which crew timetables are obtained by levelling the cover crew resources. An objective function for this problem is proposed in order to balance the number of driving and cover crews. A Lisbon Underground case study is used to illustrate The Crew Timetabling Problem. The problem is represented in a multigraph and solved by a tabu search-based heuristic.
- A network algorithm to discover sequential patternsPublication . Cavique, LuísThis paper addresses the discovery of sequential patterns in very large databases. Most of the existing algorithms use lattice structures in the space search that are very demanding computationally. The output of these algorithms generates a large number of rules. The aim of this work is to create a swift algorithm for the discovery of sequential patterns with a low time complexity. In this work, we also want to define tools that allow us to simplify the work of the final user, by offering a new visualization of the sequences, while bypassing the analysis of thousands of association rules.
- A scalable algorithm for the market basket analysisPublication . Cavique, LuísThe market basket is defined as an itemset bought together by a customer on a single visit to a store. The market basket analysis is a powerful tool for the implementation of cross-selling strategies. Especially in retailing it is essential to discover large baskets, since it deals with thousands of items. Although some algorithms can find large itemsets, they can be inefficient in terms of computational time. The aim of this paper is to present an algorithm to discover large itemset patterns for the market basket analysis. In this approach, the condensed data is used and is obtained by transforming the market basket problem into a maximum-weighted clique problem. Firstly, the input dataset is transformed into a graph-based structure and then the maximum-weighted clique problem is solved using a meta-heuristic approach in order to find the most frequent itemsets. The computational results show large itemset patterns with good scalability properties.
- Work done in kindergartens by our students orientated by distance learningPublication . Seixas, Sónia
- The computer medium in digital art's creative processPublication . Marcos, Adérito; Branco, Pedro; Carvalho, João ÁlvaroArt objects might be described as symbolic objects that aim at stimulating emotions. They reach us through our senses (visual, auditory, tactile, or other). They are displayed by means of physical material (stone, paper, wood, etc.) and combine some patterns to produce an aesthetic composition. They convey some message, normally to suggest some state of mind or to induce an emotion and the consequent feeling on the side of the viewer. Digital art differs from conventional art pieces by the use of computers and computer-based artifacts that manipulate digitally coded information, inheriting the almost unlimited possibilities in interaction, virtualization and manipulation of information the computer medium offers. In this chapter the authors propose to analyze and discuss the concepts and definitions behind digital art, emphasizing how the computer medium is itself the tool and the raw material in its creation, especially if we stress the fact that the conception and design of artistic information content is at the heart of any artistic work. Furthermore the authors present a framework for digital art creation that consists of a common design space where digital artists can smoothly progress from the concept until the final artifact while exploring the computer medium to its maximum potential.