Multi-��: an Ada 95 based architecture for fault tolerance support of real-time systems

This paper presents an architecture (Multi-��) being implemented to study and develop software based fault tolerant mechanisms for Real-Time Systems, using the Ada language (Ada 95) and Commercial Off-The-Shelf (COTS) components. Several issues regarding fault tolerance are presented and mechanisms to achieve fault tolerance by software active replication in Ada 95 are discussed. The Multi-�� architecture, based on a specifically proposed Fault Tolerance Manager (FTManager), is then described. Finally, some considerations are made about the work being done and essential future developments.

Negotiation mechanism for self-organized scheduling system

This paper presents a negotiation mechanism for Dynamic Scheduling based on Swarm Intelligence (SI). Under the new negotiation mechanism, agents must compete to obtain a global schedule. SI is the general term for several computational techniques which use ideas and get inspiration from the social behaviors of insects and other animals. This work is concerned with negotiation, the process through which multiple selfinterested agents can reach agreement over the exchange of operations on competitive resources.

Cooperation mechanism for team-work based multi-agent system in dynamic scheduling through meta-heuristics

This paper describes a Multi-agent Scheduling System that assumes the existence of several Machines Agents (which are decision-making entities) distributed inside the Manufacturing System that interact and cooperate with other agents in order to obtain optimal or near-optimal global performances. Agents have to manage their internal behaviors and their relationships with other agents via cooperative negotiation in accordance with business policies defined by the user manager. Some Multi Agent Systems (MAS) organizational aspects are considered. An original Cooperation Mechanism for a Team-work based Architecture is proposed to address dynamic scheduling using Meta-Heuristics.

Work in progress: representar o ��outro�� segundo o pensamento antropof��gico casos de estudo - Hans Staden e Les Ma��tres Fous

O presente artigo analisa o filme de Luis Alberto Pereira ��Hans Staden�� (1999), baseado no livro de Hans Staden ��Duas Viagens ao Brasil�� (1557), e o document��rio/filme ��Les Ma��tres Fous�� (1955) de Jean Rouch, tendo em considera����o o pensamento antropof��gico. Estas obras focalizam o choque cultural entre ���civilizado��� e ���selvagem���, entre ritual canibal e ritual antropof��gico, entre o ��N��s�� e os ��Outros��, encontros que permitem uma an��lise mais concreta �� concep����o de alteridade. A representa����o cinematogr��fica permite uma aproxima����o ao conceito antropof��gico de apropria����o da cultura externa, para posteriormente a reproduzir numa interpreta����o segundo a concep����o ocidental do que figuram os rituais em quest��o. O Movimento Antrop��fago, pelo seu car��cter vanguardista, concilia a matriz fundadora brasileira e ao mesmo tempo enaltece a irrever��ncia de an��lise, e neste artigo serve de fundamento te��rico e pr��tico �� decomposi����o dos exemplos. O pensamento antrop��fago e a sua aplicabilidade aos exemplos seleccionados permitem tamb��m aprofundar o estudo sobre o imagin��rio europeu enquanto recria����o de relatos datados de viajantes ou colonizadores, pois a manuten����o de um acervo estereotipado historicamente serve como forma de ���legitimar��� concep����es. As duas obras focalizam a representa����o ind��gena e africana - o ���selvagem��� - na constru����o do imagin��rio ocidental - ���civilizado��� - dicotomia que nos permite desmistificar rela����es interculturais.

Motivations in volunteer work

The objective of this paper is to review and discuss the literature about volunteers��� motivations to donate their time to NGOs (Non Governmental Organisations). According to Parboteeah, Cullenb & Lim (2004) management research has not paid much attention to voluntarism, however, voluntarism is a substantial part of productive work for many societies. Wilson & Pimm (1996) show that in Great Britain about 39% of the adult population has been involved in some volunteer activity for some period of time. In the U.S.A. these values reach 50% (Wilson & Pimm, 1996). Considering the benefits that voluntarism can bring to an organisation, we understand that more attention must be devoted to this phenomenon. The more an organisation knows volunteers, the better this organisation will be able to meet the needs and expectations of these individuals. We present a literature review that illustrates and compares the different motivations associated with volunteer work. The paper includes a bibliographical databases search in specialised journals. The search used the key words ���motivations��� and ���voluntarism��� (in the heading and text body) and covered all numbers between 2000 and 2007. We identify the existence of repeated motivations (Holmberg & S��derlung, 2005; Prouteau & Wolff, 2008; Soupourmas & Ironmonger, 2001; Yavas & Riecken, 1997), which allow the establishment of a typology of volunteers��� motivations, based on four categories: altruism, social needs, self-esteem, learning and self-development. Finally we identify three main gaps in the literature that justify further research. First, research focusing on the differences between motivations related to volunteers��� "Attraction" versus "Retention" in NGO���s is nil. Second, the great majority of the studies rely on north American (USA and Canada) and Australian context, which demands for further research in European countries. Third, the majority of NGOs researched are related to sport, art or the environment, and it would be interesting to explore the relationship between motivation and NGO type. These questions may obtain interesting answers for NGO management, in particular with regard to volunteer attraction and retention.

Motivations and management factors of volunteer work in nonprofit organisations: a literature review

The objective of this paper is to review and discuss the literature about volunteers��� motivations to donate their time to NPOs and the management factors that can influence volunteer work. Firstly, the paper illustrates and compares the different types of motivation followed by a presentation of a typology that organises the volunteers��� motivations into four types: (i) altruism, (ii) belonging, (iii) ego and social recognition and (iv) development and learning. Secondly we discuss the key management factors in volunteering: recruitment, training and rewarding. Finally, we present four gaps in the literature that justify the scope for further research: (i) omission of differences between motivations related to volunteers��� "Attraction" versus "Retention"; (ii) focus of the research on the USA, UK and Australia context; (iii) absence of comparative analyses that relate motivations by NPO types and (iv) comprehension of how management factors (recruitment, training and rewarding) influence volunteers��� satisfaction and retention.

Dynamic power- and failure-aware cloud resources allocation for Sets of independent tasks

Cloud computing is increasingly being adopted in different scenarios, like social networking, business applications, scientific experiments, etc. Relying in virtualization technology, the construction of these computing environments targets improvements in the infrastructure, such as power-efficiency and fulfillment of users��� SLA specifications. The methodology usually applied is packing all the virtual machines on the proper physical servers. However, failure occurrences in these networked computing systems can induce substantial negative impact on system performance, deviating the system from ours initial objectives. In this work, we propose adapted algorithms to dynamically map virtual machines to physical hosts, in order to improve cloud infrastructure power-efficiency, with low impact on users��� required performance. Our decision making algorithms leverage proactive fault-tolerance techniques to deal with systems failures, allied with virtual machine technology to share nodes resources in an accurately and controlled manner. The results indicate that our algorithms perform better targeting power-efficiency and SLA fulfillment, in face of cloud infrastructure failures.

Preparatory and field work phases in the qualitative empirical research process in management: the case studies approach

Purpose: The aim of this paper is to promote qualitative methodology within the scientific community of management. The specific objective is oriented to propose an empirical research process based on case study method. This is to ensure rigor in the empirical research process, that future research may follow a similar procedure to that is proposed. Design/methodology/approach: Following a qualitative methodological approach, we propose a research process that develops according to four phases, each with several stages. This study analyses the preparatory and field work phases and their stages. Findings: The paper shows the influence that case studies have on qualitative empirical research process in management. Originality/value:. Case study method assumes an important role within qualitative research by allowing for the study and analysis of certain types of phenomena that occur inside organisations, and in respect of which quantitative studies cannot provide an answer.

Monitoriza����o de desreguladores end��crinos em ��guas

Da crescente necessidade de alimentos e da necessidade de travar a destrui����o de culturas por animais e insectos foram sintetizados os pesticidas. Por entre uma vasta gama de pesticidas alguns s��o desreguladores end��crinos o que se traduz num perigo para a sa��de humana pois pode despoletar altera����es nos seres vivos mesmo em concentra����es muito baixas. Devido a diversos factores nomeadamente a lixivia����o, ventos e outros agentes ambientais assim como a presen��a de terrenos agr��colas junto a diversos rios, estes encontram-se contaminados com pesticidas desreguladores end��crinos. O objectivo deste trabalho foi avaliar quais os pesticidas desreguladores end��crinos presentes nas ��guas de rios da regi��o Norte. Neste trabalho utilizou-se a t��cnica de microextrac����o em fase s��lida recorrendo a uma fibra de PDMS (100 ��m). Para tal as condi����es de optimiza����o foram testadas nomeadamente a quantidade de NaCl, quantidade de metanol, temperatura do injector e tempo de exposi����o. Os par��metros obtidos ��ptimos foram 0 % de NaCl, tempo de exposi����o de 45 min, temperatura do injector de 260 ��C e 2,5 % de metanol. Conseguiu-se a separa����o de todos os pesticidas desreguladores end��crinos com a seguinte programa����o temperaturas: inicio a 60��C por um minuto seguido de um aumento de 20 ��C/min at�� aos 200 ��C onde permanece por um minuto e de seguida um aumento de 5 ��C/min at�� aos 245 ��C onde permanece por 40 min. Fizeram-se curvas de calibra����o entre 0,01 ��g/L e 10 ��g/L. Constatou-se no entanto uma falta de reprodutibilidade entre as injec����es utilizando esta t��cnica. Os rios analisados foram o Rio Douro, Rio T��mega, Ria de Aveiro, Rio Lima, Rio Minho, Rio Sousa, Rio ��gueda, Rio C��vado e Rio Le��a. No Rio T��mega foram encontrados os seguintes pesticidas: diazin��o, ��-HCH, ��-HCH, ��-HCH, lindano, HCB, simazina/ atrazina, vinclozolina, alacloro, 2,4-D, malati��o, aldrina, bifentrina, metoxicloro e fenvalerato. No rio Douro est��o presentes HCB, simazina/ atrazina, vinclozolina, 2,4-D, malati��o, aldrina, fenvalerato e deltametrina. No rio Lima encontra-se diazin��o, ��-HCH, ��-HCH, 2,4-D, HCB, vinclozolina, lindano, simazina/atrazina, alacloro, malati��o, aldrina, fenvalerato e deltametrina. No rio Sousa os pesticidas encontrados foram: diazin��o, HCB, aldrina, ��-HCH, ��-HCH, ��-HCH, lindano, simazina/ atrazina, 2,4-D, cipermetrina, alacloro, fenvalerato e malati��o. No rio C��vado est��o presentes o diazin��o, ��-HCH, ��-HCH, ��-HCH, lindano, HCB, 2,4-D, malati��o, metoxicloro, cipermetrina e o fenvalerato. Na ria de Aveiro encontrou-se o diazin��o, ��-HCH, ��-HCH, ��-HCH, lindano, HCB, simazina/atrazina, 2,4-D, Malati��o e aldrina. No rio ��gueda est��o presentes o diazin��o, HCB, 2,4-D, aldrina e malati��o. E por ��ltimo no rio Le��a esta presente o diazin��o, 2,4-D, alacloro, malati��o, aldrina, cipermetrina e fenvalerato. A import��ncia deste trabalho reside na demonstra����o da presen��a destes pesticidas, desreguladores end��crinos nas ��guas superficiais da regi��o Norte.

Supporting intra-task parallelism in real-time multiprocessor systems

Os sistemas de tempo real modernos geram, cada vez mais, cargas computacionais pesadas e din��micas, come��ando-se a tornar pouco expect��vel que sejam implementados em sistemas uniprocessador. Na verdade, a mudan��a de sistemas com um ��nico processador para sistemas multi- processador pode ser vista, tanto no dom��nio geral, como no de sistemas embebidos, como uma forma eficiente, em termos energ��ticos, de melhorar a performance das aplica����es. Simultaneamente, a prolifera����o das plataformas multi-processador transformaram a programa����o paralela num t��pico de elevado interesse, levando o paralelismo din��mico a ganhar rapidamente popularidade como um modelo de programa����o. A ideia, por detr��s deste modelo, �� encorajar os programadores a exporem todas as oportunidades de paralelismo atrav��s da simples indica����o de potenciais regi��es paralelas dentro das aplica����es. Todas estas anota����es s��o encaradas pelo sistema unicamente como sugest��es, podendo estas serem ignoradas e substitu��das, por construtores sequenciais equivalentes, pela pr��pria linguagem. Assim, o modo como a computa����o �� na realidade subdividida, e mapeada nos v��rios processadores, �� da responsabilidade do compilador e do sistema computacional subjacente. Ao retirar este fardo do programador, a complexidade da programa����o �� consideravelmente reduzida, o que normalmente se traduz num aumento de produtividade. Todavia, se o mecanismo de escalonamento subjacente n��o for simples e r��pido, de modo a manter o overhead geral em n��veis reduzidos, os benef��cios da gera����o de um paralelismo com uma granularidade t��o fina ser��o meramente hipot��ticos. Nesta perspetiva de escalonamento, os algoritmos que empregam uma pol��tica de workstealing s��o cada vez mais populares, com uma efici��ncia comprovada em termos de tempo, espa��o e necessidades de comunica����o. Contudo, estes algoritmos n��o contemplam restri����es temporais, nem outra qualquer forma de atribui����o de prioridades ��s tarefas, o que impossibilita que sejam diretamente aplicados a sistemas de tempo real. Al��m disso, s��o tradicionalmente implementados no runtime da linguagem, criando assim um sistema de escalonamento com dois n��veis, onde a previsibilidade, essencial a um sistema de tempo real, n��o pode ser assegurada. Nesta tese, �� descrita a forma como a abordagem de work-stealing pode ser resenhada para cumprir os requisitos de tempo real, mantendo, ao mesmo tempo, os seus princ��pios fundamentais que t��o bons resultados t��m demonstrado. Muito resumidamente, a ��nica fila de gest��o de processos convencional (deque) �� substitu��da por uma fila de deques, ordenada de forma crescente por prioridade das tarefas. De seguida, aplicamos por cima o conhecido algoritmo de escalonamento din��mico G-EDF, misturamos as regras de ambos, e assim nasce a nossa proposta: o algoritmo de escalonamento RTWS. Tirando partido da modularidade oferecida pelo escalonador do Linux, o RTWS �� adicionado como uma nova classe de escalonamento, de forma a avaliar na pr��tica se o algoritmo proposto �� vi��vel, ou seja, se garante a efici��ncia e escalonabilidade desejadas. Modificar o n��cleo do Linux �� uma tarefa complicada, devido �� complexidade das suas fun����es internas e ��s fortes interdepend��ncias entre os v��rios subsistemas. N��o obstante, um dos objetivos desta tese era ter a certeza que o RTWS �� mais do que um conceito interessante. Assim, uma parte significativa deste documento �� dedicada �� discuss��o sobre a implementa����o do RTWS e �� exposi����o de situa����es problem��ticas, muitas delas n��o consideradas em teoria, como �� o caso do desfasamento entre v��rios mecanismo de sincroniza����o. Os resultados experimentais mostram que o RTWS, em compara����o com outro trabalho pr��tico de escalonamento din��mico de tarefas com restri����es temporais, reduz significativamente o overhead de escalonamento atrav��s de um controlo de migra����es, e mudan��as de contexto, eficiente e escal��vel (pelo menos at�� 8 CPUs), ao mesmo tempo que alcan��a um bom balanceamento din��mico da carga do sistema, at�� mesmo de uma forma n��o custosa. Contudo, durante a avalia����o realizada foi detetada uma falha na implementa����o do RTWS, pela forma como facilmente desiste de roubar trabalho, o que origina per��odos de inatividade, no CPU em quest��o, quando a utiliza����o geral do sistema �� baixa. Embora o trabalho realizado se tenha focado em manter o custo de escalonamento baixo e em alcan��ar boa localidade dos dados, a escalonabilidade do sistema nunca foi negligenciada. Na verdade, o algoritmo de escalonamento proposto provou ser bastante robusto, n��o falhando qualquer meta temporal nas experi��ncias realizadas. Portanto, podemos afirmar que alguma invers��o de prioridades, causada pela sub-pol��tica de roubo BAS, n��o compromete os objetivos de escalonabilidade, e at�� ajuda a reduzir a conten����o nas estruturas de dados. Mesmo assim, o RTWS tamb��m suporta uma sub-pol��tica de roubo determin��stica: PAS. A avalia����o experimental, por��m, n��o ajudou a ter uma no����o clara do impacto de uma e de outra. No entanto, de uma maneira geral, podemos concluir que o RTWS �� uma solu����o promissora para um escalonamento eficiente de tarefas paralelas com restri����es temporais.

Literature, translation and national identity: Christina Rossetti and Rosal��a de Castro in the work of Pl��cido Castro

Pl��cido Castro���s work has aroused our interest, because it evolves around the question of Galician personality and identity. While working as a journalist and a translator or while writing essays on different literary issues, Pl��cido Castro has never forgotten his roots or his nation. One could even say that his whole life turns around Galicia. Our purpose is to make a critical analysis of his work, especially as a translator, and try to show how he used translation in order to develop national conscience and identity and to see how far his ideology interfered in the interpretation and translation of Rossetti���s poetry, in which he found a great similarity with Rosal��a de Castro���s work.

Work in progress - learning through role play games

It is commonly accepted that the educational environment has been undergoing considerable change due to the use of the Information and Communication tools. But learning depends upon actions such as experimenting, visualizing and demonstrating through which the learner succeeds in constructing his own knowledge. Although it is not easy to achieve these actions through current ICT supported learning approaches, Role Playing Games (RPG) may well develop such capacities. The creation of an interactive computer game with RPG characteristics, about the 500th anniversary of the city of Funchal, the capital of Madeira Island, is invested with compelling educational/pedagogical implications, aiming clearly at teaching history and social relations through playing. Players interpret different characters in different settings/scenarios, experiencing adventures, meeting challenges and trying to reach multiple and simultaneous goals in the areas of education, entertainment and social integration along the first 150 years of the history of Funchal. Through this process they will live and understand all the social and historical factors of that epoch.

Response of high-risk of recurrence/progression bladder tumours expressing sialyl-Tn and sialyl-6-T to BCG immunotherapy

High risk of recurrence/progression bladder tumours is treated with Bacillus Calmette-Gu��rin (BCG) immunotherapy after complete resection of the tumour. Approximately 75% of these tumours express the uncommon carbohydrate antigen sialyl-Tn (Tn), a surrogate biomarker of tumour aggressiveness. Such changes in the glycosylation of cell-surface proteins influence tumour microenvironment and immune responses that may modulate treatment outcome and the course of disease. The aim of this work is to determine the efficiency of BCG immunotherapy against tumours expressing sTn and sTn-related antigen sialyl-6-T (s6T). METHODS: In a retrospective design, 94 tumours from patients treated with BCG were screened for sTn and s6T expression. In vitro studies were conducted to determine the interaction of BCG with high-grade bladder cancer cell line overexpressing sTn. RESULTS: From the 94 cases evaluated, 36 had recurrence after BCG treatment (38.3%). Treatment outcome was influenced by age over 65 years (HR=2.668; (1.344-5.254); P=0.005), maintenance schedule (HR=0.480; (0.246-0.936); P=0.031) and multifocality (HR=2.065; (1.033-4.126); P=0.040). sTn or s6T expression was associated with BCG response (P=0.024; P<0.0001) and with increased recurrence-free survival (P=0.001). Multivariate analyses showed that sTn and/or s6T were independent predictive markers of recurrence after BCG immunotherapy (HR=0.296; (0.148-0.594); P=0.001). In vitro studies demonstrated higher adhesion and internalisation of the bacillus to cells expressing sTn, promoting cell death. CONCLUSION: s6T is described for the first time in bladder tumours. Our data strongly suggest that BCG immunotherapy is efficient against sTn- and s6T-positive tumours. Furthermore, sTn and s6T expression are independent predictive markers of BCG treatment response and may be useful in the identification of patients who could benefit more from this immunotherapy.

Using WorldFIP networks to support periodic and sporadic real-time traffic

In this paper we address the ability of WorldFIP to cope with the real-time requirements of distributed computer-controlled systems (DCCS). Typical DCCS include process variables that must be transferred between network devices both in a periodic and sporadic (aperiodic) basis. The WorldFIP protocol is designed to support both types of traffic. WorldFIP can easily guarantee the timing requirements for the periodic traffic. However, for the aperiodic traffic more complex analysis must be made in order to guarantee its timing requirements. This paper describes work that is being carried out to extend previous relevant work, in order to include the actual schedule for the periodic traffic in the worst-case response time analysis of sporadic traffic in WorldFIP networks

Supporting real-time parallel task models with work-stealing

Dynamic parallel scheduling using work-stealing has gained popularity in academia and industry for its good performance, ease of implementation and theoretical bounds on space and time. Cores treat their own double-ended queues (deques) as a stack, pushing and popping threads from the bottom, but treat the deque of another randomly selected busy core as a queue, stealing threads only from the top, whenever they are idle. However, this standard approach cannot be directly applied to real-time systems, where the importance of parallelising tasks is increasing due to the limitations of multiprocessor scheduling theory regarding parallelism. Using one deque per core is obviously a source of priority inversion since high priority tasks may eventually be enqueued after lower priority tasks, possibly leading to deadline misses as in this case the lower priority tasks are the candidates when a stealing operation occurs. Our proposal is to replace the single non-priority deque of work-stealing with ordered per-processor priority deques of ready threads. The scheduling algorithm starts with a single deque per-core, but unlike traditional work-stealing, the total number of deques in the system may now exceed the number of processors. Instead of stealing randomly, cores steal from the highest priority deque.