WAVELET BASED NONLINEAR SEPARATION OF IMAGES

This work addresses a real-life problem corresponding to the separation of the nonlinear mixture of images which arises when we scan a paper document and the image from the back page shows through. The proposed solution consists of a non-iterative procedure that is based on two simple observations: (1) the high frequency content of images is sparse, and (2) the image printed on each side of the paper appears more strongly in the mixture acquired from that side than in the mixture acquired from the opposite side. These ideas had already been used in the context of nonlinear denoising source separation (DSS). However, in that method the degree of separation achieved by applying these ideas was relatively weak, and the separation had to be improved by iterating within the DSS scheme. In this paper the application of these ideas is improved by changing the competition function and the wavelet transform that is used. These improvements allow us to achieve a good separation in one shot, without the need to integrate the process into an iterative DSS scheme. The resulting separation process is both nonlinear and non-local. We present experimental results that show that the method achieves a good separation quality

O contributo da auditoria pública para a Good Governance

Dissertação de Mestrado em Gestão e Políticas PúblicasEste trabalho visa discutir o papel das ISC enquanto entidades de auditoria pública, e qual o seu contributo para a good governance. Das diversas pesquisas bibliográficas efetuadas, apurou-se que a good governance é tida como uma forma de governação, boa, que assenta em participação pública, em transparência, responsabilização, respeito, cumprimento da lei e satisfação das necessidades das populações, onde se basearia a força do desenvolvimento social. Face aos objetivos de trabalho definidos, foi assim produzido e aplicado um guião de entrevista a vários intervenientes qualificados de auditoria pública, tendo-se recolhido opinião, experiências e visão sobre o modo como a good governance acontece hoje em Portugal, nomeadamente quanto à transparência da governação, quanto acautela os riscos da atividade pública e quanto permite a aplicação da accountability. A utilização e aplicação de auditoria pública, facilitará o processo de criação de valor e confiança pública de toda uma comunidade. De acordo com a literatura de referência e com os entrevistados, a auditoria de contexto público tem um papel determinante na concretização da good governance. De resto, vários organismos internacionais de referência (OCDE, ONU, FMI, Banco Mundial, entre outros) perseguem e fomentam a prática da good governance, não só, mas também, com recurso ao reforço de práticas e procedimentos de auditoria pública, fazendo relevar o papel complementar entre a produção de auditorias de compliance e de auditorias de performance. Das entrevistas aos intervenientes qualificados nestas matérias, foram obtidos importantes contributos, em especial de reforço da prática da good governance através da auditoria pública e dos relatórios produzidos por esta, reforçando assim a cidadania.This paper aims to discuss the role of SAIs as public audit entities, and is contribution to good governance. From the various bibliographical studies carried out, it was found that good governance is considered as a good form of governance, based on public participation, transparency, accountability, respect, compliance with the law and meeting the needs of the population for social development. In view of the defined work objectives, an interview guide was produced and applied to a number of qualified interviewees which used public audit. Their opinions, experiences and insights were collected on how good governance occurs; how it is transparent and of much to guard against the risks of public activity and how much it allows the application of accountability today in Portugal. The public audit outcome will be to create public value and trust for an entire community. According to the reference literature and the interviewees, the public context audit plays a decisive role in the achievement of good governance. In addition, several international reference organizations (OECD, UN, IMF, World Bank, among others) pursue and foster good governance not only, but also through the reinforcement of public auditing practices and procedures, regarding the complementary role between the production of compliance audits and performance audits. From the interviews with the qualified actors in these matters, important contributions were obtained, in particular to reinforce the practice of good governance through public auditing and the reports produced by it, thus reinforcing citizenship.N/

Mean curvature flow with obstacles

We consider the evolution of fronts by mean curvature in the presence of obstacles. We construct a weak solution to the flow by means of a variational method, corresponding to an implicit time-discretization scheme. Assuming the regularity of the obstacles, in the two-dimensional case we show existence and uniqueness of a regular solution before the onset of singularities. Finally, we discuss an application of this result to the positive mean curvature flow.Comment: 18 page

Existence and diffusive limit of a two-species kinetic model of chemotaxis

In this paper, we propose a kinetic model describing the collective motion by chemotaxis of two species in interaction emitting the same chemoattractant. Such model can be seen as a generalisation to several species of the Othmer-Dunbar-Alt model which takes into account the run-and-tumble process of bacteria. Existence of weak solutions for this two-species kinetic model is studied and the convergence of its diffusive limit towards a macroscopic model of Keller-Segel type is analysed

Large scale railway renewal planning with a multiobjective modeling approach

Conferência realizada na Filândia, Helsinquia, de 20-24 de agosto de 2018A multiobjective modeling approach for managing large scale railway infrastructure asset renewal is presented. An optimized intervention project schedule is obtained considering operational constraints in a three objectives model: evenly spreading investment throughout multiple years, minimizing total cost, minimizing work start postponements on higher priority railway sections. The MILP model was based on a real world case study; the objectives and constraints specified by an infrastructure management company. Results show that investment spreading greatly influences the other objectives and that total cost fluctuations depend on the overall condition of the railway infrastructure. The model can produce exact efficient solutions in reasonable time, even for very large-sized instances (a test network of similar size to the USA railway network, the largest in the world). The modeling approach is therefore a very useful, practical methodology, for generating optimized solutions and analyzing trade-offs among objectives, easing the task of ultimately selecting a solution and produce the works schedule for field implementation.info:eu-repo/semantics/publishedVersio

Bi-objective modeling approach for repairing multiple feature infrastructure systems

A bi-objective decision aid model for planning long-term maintenance of infrastructure systems is presented, oriented to interventions on their constituent elements, with two upgrade levels possible for each element (partial/full repairs). The model aims at maximizing benefits and minimizing costs, and its novelty is taking into consideration, and combining, the system/element structure, volume discounts, and socioeconomic factors. The model is tested with field data from 229 sidewalks (systems) and compared to two simpler repair policies, of allowing only partial or full repairs. Results show that the efficiency gains are greater in the lower mid-range budget region. The proposed modeling approach is an innovative tool to optimize cost/benefits for the various repair options and analyze the respective trade-offs.info:eu-repo/semantics/publishedVersio

Multi-objective model for optimizing railway infrastructure asset renewal

Trabalho inspirado num problema real da empresa Infraestruturas de Portugal, EP.A multi-objective model for managing railway infrastructure asset renewal is presented. The model aims to optimize three objectives, while respecting operational constraints: levelling investment throughout multiple years, minimizing total cost and minimizing work start postponements. Its output is an optimized intervention schedule. The model is based on a case study from a Portuguese infrastructure management company, which specified the objectives and constraints, and reflects management practice on railway infrastructure. The results show that investment levelling greatly influences the other objectives and that total cost fluctuations may range from insignificant to important, depending on the condition of the infrastructure. The results structure is argued to be general and suggests a practical methodology for analysing trade-offs and selecting a solution for implementation.info:eu-repo/semantics/publishedVersio

Functionalisation of textiles: future perspectives

Multifunctional effects are essential for producing higher value added textiles, important not only for new technical applications but also for more “traditional” uses such as clothing and home textiles with high product differentiation. Within the “European Technology Platform for the Future of Textiles and Clothing”, functional textiles are a clear priority. Surface modification by means of finishing is very versatile and allows a large number of effects. The developments of new functional effects also lead to the need of the development of specific test methods that are able to measure the effectiveness, durability and toxicity of the claimed functionalities. The technical committee for “textiles and textile products” of the European Standardisation is now devoting special attention to this subject

Youth football injury epidemiology : a prospective study on workload and musculoskeletal risk factors

Purpose: (A) To characterize the epidemiology of injury at an elite youth football academy. (B) To investigate the differences between injured and non-injured elite youth footballers in musculoskeletal screening and workload variables, for lower extremity non-contact soft tissue injuries; and for groin located and muscular type injuries. Methods: (A) Prospective analysis of time-loss injuries from one hundred eighty-four elite youth male football players (age: 16.2±2.2 yrs) in a Portuguese academy (U14-U23) during the 2019-2020 season. Injury frequency, burden, incidence, and patterns were calculated. (B) A match-paired case approach was used to investigate differences between injured (n= 56) and non-injured (n= 56) groups for preseason musculoskeletal screening variables (passive knee fall out (PKFO), adductor squeeze (ASQZ), adductor squeeze bodyweight ratio (ASQZ/BWratio), dorsiflexion lunge test (DLT); single-leg countermovement jump (SL-CMJ)) and workload variables before injury (Cumulative sum; monotony; strain; acute: chronic workload ratio (ACWR); week to week change) using internal load (sRPE). Groin located injuries (n=14 vs n=14) and muscular injuries (n= 27 vs n=27) were also investigated. Results: (A) A total of 129 time-loss injuries were observed. Injuries were more frequent in training but had a higher incidence and burden rate in match context. Overall incidence was 2.7 per 1000 hours, and burden rate 59.3 days lost per 1000 hours. The thigh was the most frequent location. Quadriceps was the most injured muscle group, mainly by sprinting and shooting mechanisms. Moderate injuries were more frequent, with a mean of 21.9±28 days lost to injury. Under 17 was the most affected team, with the highest-burden cross-product. (B) ASQZ/BWratio was higher in non-injured players compared with injured players for lower body non-contact (0.64±0.11 vs 0.59±0.11; p=0.025) and groin injuries (0.64±0.08 vs 0.54±0.11; p=0.007). No other workload and musculoskeletal variable had significant differences between groups. Conclusions: Characteristics of injury incidence, burden, and patterns differ among squads in elite youth football. Non-contact injuries in pre-adolescent players remain frequent, representing a threat to the young football player's safe development. ASQZ/BWratio could be used to identify risk of injury for lower body non-contact and groin injuries. More data is necessary to clarify which musculoskeletal and workload factors are relevant to youth football injury occurrence.Objetivo: (A) Caracterizar a epidemiologia de lesões numa academia de futebol jovem de elite. (B) Investigar as diferenças entre jogadores lesionados e não lesionados para variáveis músculo-esqueléticas e carga de treino, para lesões sem contacto de membro inferior de tecidos moles; e para lesões localizadas na púbis e lesões do tipo muscular. Métodos: (A) Análise prospetiva de lesões de cento e oitenta e quatro jogadores de futebol jovem de elite (idade, 16.2±2.2 anos) numa academia portuguesa (U14-U23) durante a época 2019-2020. A frequência, carga, incidência e padrões das lesões foram calculados. (B) Foi utilizada uma comparação entre pares para investigar as diferenças entre grupos lesionado (n= 56) e não lesionado (n= 56) para as variáveis músculo-esqueléticas de pré-época (queda passiva do joelho (PKFO), força de adutores (ASQZ), rácio força de adutores e de peso corporal (ASQZ/BWratio), teste de dorsiflexão em lunge (DLT); salto de contramovimento unilateral (SL-CMJ)) e variáveis de carga de treino (soma cumulativa; monotonia; strain; rácio agudo: crónico (ACWR); diferença entre semanas) usando carga interna (sRPE). Lesões localizadas na virilha (n=14 vs n=14) e lesões do tipo muscular (n= 27 vs n=27) também foram investigadas. Resultados: (A) Foram observadas um total de 129 lesões. As lesões foram mais frequentes em treino, mas com maior incidência e severidade em jogo. A incidência foi de 2.7 lesões /1000 horas, e a severidade de 59.3 dias perdidos /1000 horas. A coxa foi o local mais frequente. O quadríceps foi o grupo muscular mais lesionado, principalmente por sprint e remate. Lesões de severidade moderada foram mais frequentes, com 21.9±28 dias perdidos por lesão. Os Sub17 foram a equipa mais afetada. (B) O ASQZ/BWratio foi mais elevado em jogadores sem lesão, em comparação com os jogadores lesionados (0.64±0.11 vs 0.59±0.11; p=0.025; d=0.401) para lesões do membro inferior sem contacto e lesões na virilha (0.64±0.08 vs 0.54±0.11; p=0.007; d=1.107). Nenhuma outra variável músculo-esquelética ou de carga de treino apresentou diferenças significativas entre grupos. Conclusões: As características de incidência de lesão diferem entre equipas de futebol jovem de elite. As lesões sem contacto em jogadores jovens continuam frequentes, representando uma ameaça para o seu desenvolvimento saudável. O rácio ASQZ/BWratio poderá ser usado para determinar risco de lesão do membro inferior e, mais especificamente, para lesões localizadas na púbis