Constraint solving over multi-valued logics - application to digital circuits

Due to usage conditions, hazardous environments or intentional causes, physical and virtual systems are subject to faults in their components, which may affect their overall behaviour. In a ‘black-box’ agent modelled by a set of propositional logic rules, in which just a subset of components is externally visible, such faults may only be recognised by examining some output function of the agent. A (fault-free) model of the agent’s system provides the expected output given some input. If the real output differs from that predicted output, then the system is faulty. However, some faults may only become apparent in the system output when appropriate inputs are given. A number of problems regarding both testing and diagnosis thus arise, such as testing a fault, testing the whole system, finding possible faults and differentiating them to locate the correct one. The corresponding optimisation problems of finding solutions that require minimum resources are also very relevant in industry, as is minimal diagnosis. In this dissertation we use a well established set of benchmark circuits to address such diagnostic related problems and propose and develop models with different logics that we formalise and generalise as much as possible. We also prove that all techniques generalise to agents and to multiple faults. The developed multi-valued logics extend the usual Boolean logic (suitable for faultfree models) by encoding values with some dependency (usually on faults). Such logics thus allow modelling an arbitrary number of diagnostic theories. Each problem is subsequently solved with CLP solvers that we implement and discuss, together with a new efficient search technique that we present. We compare our results with other approaches such as SAT (that require substantial duplication of circuits), showing the effectiveness of constraints over multi-valued logics, and also the adequacy of a general set constraint solver (with special inferences over set functions such as cardinality) on other problems. In addition, for an optimisation problem, we integrate local search with a constructive approach (branch-and-bound) using a variety of logics to improve an existing efficient tool based on SAT and ILP.

Constraint reasoning for differential models

The basic motivation of this work was the integration of biophysical models within the interval constraints framework for decision support. Comparing the major features of biophysical models with the expressive power of the existing interval constraints framework, it was clear that the most important inadequacy was related with the representation of differential equations. System dynamics is often modelled through differential equations but there was no way of expressing a differential equation as a constraint and integrate it within the constraints framework. Consequently, the goal of this work is focussed on the integration of ordinary differential equations within the interval constraints framework, which for this purpose is extended with the new formalism of Constraint Satisfaction Differential Problems. Such framework allows the specification of ordinary differential equations, together with related information, by means of constraints, and provides efficient propagation techniques for pruning the domains of their variables. This enabled the integration of all such information in a single constraint whose variables may subsequently be used in other constraints of the model. The specific method used for pruning its variable domains can then be combined with the pruning methods associated with the other constraints in an overall propagation algorithm for reducing the bounds of all model variables. The application of the constraint propagation algorithm for pruning the variable domains, that is, the enforcement of local-consistency, turned out to be insufficient to support decision in practical problems that include differential equations. The domain pruning achieved is not, in general, sufficient to allow safe decisions and the main reason derives from the non-linearity of the differential equations. Consequently, a complementary goal of this work proposes a new strong consistency criterion, Global Hull-consistency, particularly suited to decision support with differential models, by presenting an adequate trade-of between domain pruning and computational effort. Several alternative algorithms are proposed for enforcing Global Hull-consistency and, due to their complexity, an effort was made to provide implementations able to supply any-time pruning results. Since the consistency criterion is dependent on the existence of canonical solutions, it is proposed a local search approach that can be integrated with constraint propagation in continuous domains and, in particular, with the enforcing algorithms for anticipating the finding of canonical solutions. The last goal of this work is the validation of the approach as an important contribution for the integration of biophysical models within decision support. Consequently, a prototype application that integrated all the proposed extensions to the interval constraints framework is developed and used for solving problems in different biophysical domains.

Future gender relations in global restructuring processes case study evidence from knowledge-intensive, manufacturing and service occupations

Global restructuring processes have not only strong implications for European working and living realities, but also have specific outcomes with regard to gender relations. The following contribution analyses in which way global restructuring shapes current gender relations in order to identify important trends and developments for future gender (in)equalities at the workplace. On the basis of a large qualitative study on global restructuring and impacts on different occupational groups it argues that occupational belonging in line with skill and qualification levels are crucial factors to assess the further development of gender relations at work. Whereas global restructuring in knowledge-based occupations may provide new opportunities for female employees, current restructuring is going to deteriorate female labour participation in service occupations. In contrast, manufacturing occupations can be characterised by persistent gender relations, which do not change in spite of major restructuring processes at the work place. Taking the institutional perspective into account, it seems to be crucial to integrate the occupational perspective in order to apply adequate policy regulations to prevent the reinforcement of gender related working patterns in the near future.

Integrating the theme approach with aspectual scenarios

Dissertação de Mestrado em Engenharia Informática

A Web-Based geographical information system prototype on Portuguese traditional food products

Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial Technologies

The black box of health care expenditure growth determinants

In this paper, the determinants of growth of aggregate health expenditures are investigated. The study departs from previous literature in that it looks at differences across countries in growth (and not levels) of health care expenditures. Estimation is made for 24 OECD countries. Health system characteristics usually believed to influence health expenditures growth, like population ageing, the type of health system (public reimbursement, public contract or integrate) and existence of gatekeepers, are found to be non-significant. Nevertheless, there is evidence that health expenditures experienced a clear slower growth in the last decade. The explanation for this slowdown could not be found in the proposed model and should stimulate further research.

Wetland Habitat Studies using various Classification Techniques on Multi-Spectral Landsat Imagery: Case study: Tram chim National Park, Dong Thap Vietnam

Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial Technologies

Designing market-based instruments for biodiversity conservation: learning with the Australian experience and evaluating Portugal's potential

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia do Ambiente, perfil Gestão de Sistemas Ambientais

Learning to manage in knowledge-based organizations: the role of learning logs or portfolios

Paper presented at the 8th European Conference on Knowledge Management, Barcelona, 6-7 Sep. 2008 URL: http://www.academic-conferences.org/eckm/eckm2007/eckm07-home.htm

Context-aware multi-factor authentication

Trabalho apresentado no âmbito do Mestrado em Engenharia Informática, como requisito parcial para obtenção do grau de Mestre em Engenharia Informática

Downstream processing development of enveloped viruses for clinical applications: innovative tools for rational process optimization

Dissertation presented to obtain a Ph.D. degree in Engineering and Technology Sciences, Biotechnology at the Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa

Contributo para a gestão da qualidade clínica num serviço de radiologia

RESUMO - A preocupação com a qualidade dos cuidados prestados é, actualmente, foco de interesse e de extrema importância na prestação de cuidados de saúde, e como tal na radiologia. A garantia, monitorização e melhoria da qualidade deve ser um dos grandes objectivos de uma instituição de saúde. Assim, pretende-se contribuir para a criação de um modelo de gestão da qualidade focado na qualidade do diagnóstico, identificando procedimentos que interferem directamente na qualidade do diagnóstico e que, ao serem implementados, contribuem para a garantia e/ou melhoria da qualidade desse diagnóstico. Tal modelo pode integrar um sistema de gestão da qualidade total num serviço de radiologia. O delineamento do estudo passa por propor a um painel de especialistas os procedimentos essenciais encontrados na bibliografia para que estes, por consenso, seleccionem os considerados mais importantes. Pretende-se também conhecer, recorrendo ao mesmo painel de peritos, os indicadores que devem integrar o modelo, de forma a construir um modelo de gestão da qualidade clínica em radiologia adaptado à realidade nacional. Os objectivos do sistema de qualidade proposto passam por fornecer uma abordagem sistemática de actividades que possam afectar a qualidade através da construção de procedimentos claros e objectivos aplicáveis a cada área de um serviço de radiologia: área administrativa, área técnica e área médica; privilegiar as actividades de prevenção em vez que confiar apenas na inspecção, na medida em que os procedimentos integram normas que minimizam a existência de falha na qualidade clínica; fornecer uma evidência objectiva de que a qualidade foi alcançada através de indicadores que monitorizam os procedimentos do modelo. A finalidade passa por criar um modelo de gestão da qualidade clínica, constituído por procedimentos e indicadores, focado na melhoria da qualidade do diagnóstico clínico em radiologia. Por ser um estudo pioneiro, o modelo deve ser simples, de fácil implementação nos serviços de radiologia, e passível de ser monitorizado e avaliado, interna e externamente. --------------------ABSTRACT - The concern about the quality of care is currently the focus of interest and paramount importance, in healthcare and in radiology. Therefore, quality monitoring and its improvement must be one of the major objectives of a healthcare institution on health, when compared to current diversity. Thus, it is intended to create a model of quality management focused on the quality of diagnosis, identifying procedures that directly interfere in the quality of diagnosis and which, when completed, contributes to a warranty and / or improvement of the quality of diagnosis. This model can integrate a system of total quality management in a radiology department. The study design is to propose to a panel of experts the essential procedures found in the literature so that they, by consensus, select those considered most important. The aim is also to know, using the same panel of experts, indicators that must be included in the model in order to construct a model of quality management in clinical radiology adapted to national reality. The objectives of the quality system proposed are: provide a systematic approach of activities that may affect the quality through the construction of clear procedures and targets applicable to each area of a radiology department: the administrative, technical and medical area; focus on activities prevention rather than relying solely on inspection, once the procedures and activities integrate standards that minimize the existence of failure in clinical quality; provide objective evidence that quality has been achieved through indicators that monitor the procedures of the model. The purpose of this study is to create a clinical quality management model, constituted by procedures and indicators, focused on improving the quality of clinical diagnosis in radiology. Being a pioneering study, the model should be simple, easy to implement in the department of radiology and easily monitored and evaluated internally and externally.

Bioenergy competency centre: study of the bioenergy potencial in the centre region of Portugal.

Dissertação apresentada como requisito parcial para obtenção do grau de Mestre em Ciência e Sistemas de Informação Geográfica

Modern techniques for constraint solving the CASPER experience

Dissertação apresentada para obtenção do Grau de Doutor em Engenharia Informática, pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

A new model for EEZ surveillance and management in Portugal

Management Information Systems 2000, p. 103-111