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

2015

MODUS: uma metodologia de prototipagem de interfaces baseada em modelos

Authors
Machado, Marina; Campos, José C.; Couto, Rui;

Publication

Abstract
A interface de utilizador é essencial para o sucesso de uma aplicação, ora a sua implementação requer tempo e esforço. Metodologias baseadas em modelos suportadas por uma geração automática têm sido propostas como solução para reduzir os custos de desenvolvimento. No entanto, um elevado nível de automação nestas abordagens requer o uso de modelos detalhados da interface, originando complicações. Por um lado, esta perspetiva é contrária a uma conceção baseada no progressivo refinamento de mockups, típica do desenvolvimento de interfaces. Por outro lado, obriga uma distinção entre os modelos utilizados na lógica de negócio e na interface. Este artigo propõe uma abordagem para gerar a interface de utilizador baseada diretamente em modelos estruturais da lógica de negócio. A identificação do domínio de aplicação é um factor chave da metodologia, permitindo automatizar o processo de geração. Por sua vez a separação entre conteúdo e forma favorece o refinamento iterativo das interfaces geradas.

2015

A low cost auto-filling and refrigeration rate regulated liquid nitrogen controller for near infrared instruments

Authors
Anugu, N; Amorim, A; Garcia, P; Gordo, P; Frederico, T; Abreu, J;

Publication
U.Porto Journal of Engineering

Abstract
Liquid Nitrogen is one of the key refrigerating elements in cooling near infrared science instruments to reduce the dark, readout noises and thermal emissions in the near infrared originated from the instrument structure. Usually, a small liquid nitrogen tank connected to the near infrared instrument is auto filled from a large Dewar in order to maintain required low temperatures during the experiment for several hours. The detectors used in these instruments are quite expensive and they need to be cooled down steadily (< 2K/min) to avoid mechanical damage. The steady state cooling of the detector is the key requirement to be considered while cooling down the detector. In this paper, a controller is developed to auto-fill the liquid nitrogen tank and also to keep the refrigeration rate of the detector below 2K/min. A systematic survey of auto-filling controllers is studied. The auto-filling of liquid nitrogen from Dewar to tank is implemented with a standard on-off controller. To address the critical refrigeration rate of the detector, two approaches are studied: a) by fixed time pumping; b) by feedback the detector cooling rate. In this work we have used inexpensive equipment to develop this controller. It is very successfully used for GRAVITY acquisition camera, a near infrared instrument for European Southern Observatory. This controller has been stable and efficient for our experiment. This low cost controller can be used for any student laboratory and research.

2015

Polymeric Optical Fiber Tweezers as a tool for single cell micro manipulation and sensing

Authors
Rodrigues Ribeiro, RSR; Soppera, O; Guerreiro, A; Jorge, PAS;

Publication
24TH INTERNATIONAL CONFERENCE ON OPTICAL FIBRE SENSORS

Abstract
In this paper a new type of polymeric fiber optic tweezers for single cell manipulation is reported. The optical trapping of a yeast cell using a polymeric micro lens fabricated by guided photo polymerization at the fiber tip is demonstrated. The 2D trapping of the yeast cells is analyzed and maximum optical forces on the pN range are calculated. The experimental results are supported by computational simulations using a FDTD method. Moreover, new insights on the potential for simultaneous sensing and optical trapping, are presented.

2015

Layers, resources and property templates in the specification and analysis of two interactive systems

Authors
Campos, José C.; Curzon, Paul; Masci, Paolo; Harrison, Michael douglas;

Publication

Abstract
The paper briefly explores a layered approach to the analysis of two interactive systems (Nuclear Control and Air Traffic Control), indicating how the analysis enables exploration of the particular features emphasised by the use cases relating to the examples. These features relate to the interactive behaviour of the systems. To facilitate the analysis, property templates are proposed as heuristics for developing appropriate requirements for the respective user interfaces.

2015

A Structural Approach to Assess Graph-Based Exercises

Authors
Sousa, R; Leal, JP;

Publication
LANGUAGES, APPLICATIONS AND TECHNOLOGIES, SLATE 2015

Abstract
This paper proposes a structure driven approach to assess graph-based exercises. Given two graphs, a solution and an attempt of a student, this approach computes a mapping between the node sets of both graphs that maximizes the student's grade, as well as a description of the differences between the two graph. The proposed algorithm uses heuristics to test the most promising mappings first and prune the remaining when it is sure that a better mapping cannot be computed. The proposed algorithm is applicable to any type of document that can be parsed into its graph-inspired data model. This data model is able to accommodate diagram languages, such as UML or ER diagrams, for which this kind of assessment is typically used. However, the motivation for developing this algorithm is to combine it with other assessment models, such as the test case model used for programming language assessment. The proposed algorithm was validated with thousands of graphs with different features produced by a synthetic data generator. Several experiments were designed to analyse the impact of different features such as graph size, and amount of difference between solution and attempt.

2015

Comparing Mixed & Integer Programming vs. Constraint Programming by solving Job-Shop Scheduling Problems

Authors
Oliveira, RMeSd; Ribeiro, MSFOdC;

Publication
Independent Journal of Management & Production

Abstract

  • 2441
  • 4186