An Examination of Psychological Meaningfulness, Safety, and Availability as the Underlying Mechanisms linking Job Features and Personal Characteristics to Work Engagement

The present study tested a nomological net of work engagement that was derived from its extant research. Two of the main work engagement models that have been presented and empirically tested in the literature, the JD-R model and Kahn’s model, were integrated to test the effects that job features and personal characteristics can have on work engagement through the psychological conditions of meaningfulness, safety, and availability. In this study, safety refers to psychological perceptions of safety and not workplace safety behaviors. The job features that were tested in this model included person-job fit, autonomy, co-worker relations, supervisor support, procedural justice, and interactional justice, while the personal characteristics consisted of self-consciousness, self-efficacy, extraversion, and neuroticism. Thirty-four hypotheses and a conceptual model were tested in order to establish the viability of this nomological net of work engagement in which it was expected that meaningfulness would mediate the relationships between job features and work engagement, safety would mediate the relationships that job features and personal characteristics have with work engagement, and availability (physical, emotional, and cognitive resources) would mediate the relationships that personal characteristics have with work engagement. Furthermore, analyses were run in order to determine the factor structure of work engagement, assess whether or not it exhibits differential validity from organizational commitment and job satisfaction, and confirm that it is positively related to the outcome variable of organizational citizenship behavior (OCB). The final sample consisted of 500 workers from an online labor market who responded to a questionnaire composed of measures of all constructs included in this study. Findings show that work engagement is best represented as a three-factor construct, composed of vigor, dedication and absorption. Furthermore, support was found for the distinction of work engagement from the related constructs of organizational commitment and job satisfaction. With regard to the proposed model, meaningfulness proved to be the strongest predictor of work engagement. Results show that it partially mediates the relationships that all job features have with work engagement. Safety proved to be a partial mediator of the relationships that autonomy, co-worker relations, supervisor support, procedural justice, interactional justice, and self-efficacy have with work engagement, and fully mediate the relationship between neuroticism and work engagement. Findings also show that availability partially mediates the positive relationships that extraversion and self-efficacy have with work engagement, and fully mediates the negative relationship that neuroticism has with work engagement. Finally, a positive relationship was found between work engagement and OCB. Research and organizational implications are discussed.

Hairpin windings for high reliability and high power density electrical machines

In the last years the increasing demand of higher torque and power densities has led to the adoption of hairpin windings (HWs) in electrical machines, mainly in those intended for automotive applications. However, this winding topology is quite sensitive to AC losses, hence one of their main challenges is represented by their reduction. This work deals with different design aspects related to the enhancements of some performance figures of rotating electrical machines for traction applications, above all power density and reliability, mainly through the adoption of HWs.

Distributed computer-controlled systems: the DEAR-COTS approach

This paper proposes a new architecture targeting real-time and reliable Distributed Computer-Controlled Systems (DCCS). This architecture provides a structured approach for the integration of soft and/or hard real-time applications with Commercial O -The-Shelf (COTS) components. The Timely Computing Base model is used as the reference model to deal with the heterogeneity of system components with respect to guaranteeing the timeliness of applications. The reliability and availability requirements of hard real-time applications are guaranteed by a software-based fault-tolerance approach.

Análise e otimização de processo no departamento de manutenção de uma empresa industrial

As empresas no século XXI têm necessidade de reduzir os seus custos de manutenção para serem competitivas num mercado cada vez mais global, implementando a Manutenção Lean no setor diretamente responsável pela Manutenção e também estender a toda a organização. Este trabalho foi realizado no âmbito do estágio efetuado na empresa Lameirinho, empresa líder de Têxtil-Lar, localizada na zona de Guimarães e que possui um Departamento de Manutenção onde a fiabilidade e disponibilidade dos equipamentos é um aspeto importante bem como a sua manutenção a custos reduzidos. Assim, tendo como objetivo a melhoria do Departamento de Manutenção da empresa Lameirinho foi efetuada uma auditoria de Manutenção Lean com o intuito de determinar o estado atual, foram identificados problemas e oportunidades de melhoria bem como foram apresentadas soluções para os mesmos. Os benefícios que se obtêm com a implementação das soluções são, entre outros: melhor planeamento das intervenções de Manutenção com alocação no momento necessário dos recursos humanos e a disponibilização de peças assim como as intervenções de manutenção serem efetuadas quando a Produção menos necessita do equipamento produtivo; redução e eliminação das intervenções de Manutenção Corretiva de Emergência; redução dos custos de Manutenção na globalidade da empresa através dos benefícios obtidos e com impacto direto nos resultados económicos da empresa.

TSKY: a dependable middleware solution for data privacy using public storage clouds

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

Cost-effectiveness analysis in South Karelia Central Hospital

The target organization of this study, otherwise South-Karelia Social and Health Care District (Eksote) provides health, senior, family and social welfare services. South Karelia Central Hospital provides special health care and offers health services from all of the most important medical specialties. Eksote has in use 15D instrument to measure the health-related quality of life (HRQoL) of their patients before and after their interventions for observing the health effects of the medical care. Furthermore, 15D allows measuring the effectiveness and cost-effectiveness of health care when comparing these before and after results of the 15D measurements and adding the costs of the interventions into this research. The main purposes of this study were to analyze the effectiveness and cost-effectiveness of medical care in South Karelia Central Hospital by using the gathered 15D data to calculate effectiveness and cost-effectiveness ratios and to analyze the reliability and availability of the data. Study has been conducted using literature review and quantitative research methods. The results indicate that from the patients within the eight units selected to this study the 15D change information was available from the 52 %, the 15D change and the cost information from 38 % and the information of quality-adjusted life years (QALYs) produced and the cost information from 35 %. The effectiveness and cost-effectiveness of medical care were greatest at the units of Pain Outpatient Clinic and Rheumatic Diseases Outpatient Clinic. The most effective medical care is given in the unit where the average price of one produced QALY is the highest (Orthopedics). However, the calculated standard deviations pointed out that there are great variances in the effectiveness and cost-effectiveness within the units also.

Enhanced fault recovery methods for protected traffic services in GMPLS networks

Les noves tecnologies a la xarxa ens permeten transportar, cada cop més, grans volums d' informació i trànsit de xarxa amb diferents nivells de prioritat. En aquest escenari, on s'ofereix una millor qualitat de servei, les conseqüències d'una fallada en un enllaç o en un node esdevenen més importants. Multiprotocol Lavel Switching (MPLS), juntament amb l'extensió a MPLS generalitzat (GMPLS), proporcionen mecanismes ràpids de recuperació de fallada establint camins, Label Switch Path (LSPs), redundants per ser utilitzats com a camins alternatius. En cas de fallada podrem utilitzar aquests camins per redireccionar el trànsit. El principal objectiu d'aquesta tesi ha estat millorar alguns dels actuals mecanismes de recuperació de fallades MPLS/GMPLS, amb l'objectiu de suportar els requeriments de protecció dels serveis proporcionats per la nova Internet. Per tal de fer aquesta avaluació s'han tingut en compte alguns paràmetres de qualitat de protecció com els temps de recuperació de fallada, les pèrdues de paquets o el consum de recursos. En aquesta tesi presentem una completa revisió i comparació dels principals mètodes de recuperació de fallada basats en MPLS. Aquest anàlisi inclou els mètodes de protecció del camí (backups globals, backups inversos i protecció 1+1), els mètodes de protecció locals i els mètodes de protecció de segments. També s'ha tingut en compte l'extensió d'aquests mecanismes a les xarxes òptiques mitjançant el pla de control proporcionat per GMPLS. En una primera fase d'aquest treball, cada mètode de recuperació de fallades és analitzat sense tenir en compte restriccions de recursos o de topologia. Aquest anàlisi ens dóna una primera classificació dels millors mecanismes de protecció en termes de pèrdues de paquets i temps de recuperació. Aquest primer anàlisi no és aplicable a xarxes reals. Per tal de tenir en compte aquest nou escenari, en una segona fase, s'analitzen els algorismes d'encaminament on sí tindrem en compte aquestes limitacions i restriccions de la xarxa. Es presenten alguns dels principals algorismes d'encaminament amb qualitat de servei i alguna de les principals propostes d'encaminament per xarxes MPLS. La majoria dels actual algorismes d'encaminament no tenen en compte l'establiment de rutes alternatives o utilitzen els mateixos objectius per seleccionar els camins de treball i els de protecció. Per millorar el nivell de protecció introduïm i formalitzem dos nous conceptes: la Probabilitat de fallada de la xarxa i l'Impacte de fallada. Un anàlisi de la xarxa a nivell físic proporciona un primer element per avaluar el nivell de protecció en termes de fiabilitat i disponibilitat de la xarxa. Formalitzem l'impacte d'una fallada, quant a la degradació de la qualitat de servei (en termes de retard i pèrdues de paquets). Expliquem la nostra proposta per reduir la probabilitat de fallada i l'impacte de fallada. Per últim fem una nova definició i classificació dels serveis de xarxa segons els valors requerits de probabilitat de fallada i impacte. Un dels aspectes que destaquem dels resultats d'aquesta tesi és que els mecanismes de protecció global del camí maximitzen la fiabilitat de la xarxa, mentre que les tècniques de protecció local o de segments de xarxa minimitzen l'impacte de fallada. Per tant podem assolir mínim impacte i màxima fiabilitat aplicant protecció local a tota la xarxa, però no és una proposta escalable en termes de consum de recursos. Nosaltres proposem un mecanisme intermig, aplicant protecció de segments combinat amb el nostre model d'avaluació de la probabilitat de fallada. Resumint, aquesta tesi presenta diversos mecanismes per l'anàlisi del nivell de protecció de la xarxa. Els resultats dels models i mecanismes proposats milloren la fiabilitat i minimitzen l'impacte d'una fallada en la xarxa.

Uma metodologia para modelagem e avaliação da dependabilidade de redes industriais sem fio

Ensuring the dependability requirements is essential for the industrial applications since faults may cause failures whose consequences result in economic losses, environmental damage or hurting people. Therefore, faced from the relevance of topic, this thesis proposes a methodology for the dependability evaluation of industrial wireless networks (WirelessHART, ISA100.11a, WIA-PA) on early design phase. However, the proposal can be easily adapted to maintenance and expansion stages of network. The proposal uses graph theory and fault tree formalism to create automatically an analytical model from a given wireless industrial network topology, where the dependability can be evaluated. The evaluation metrics supported are the reliability, availability, MTTF (mean time to failure), importance measures of devices, redundancy aspects and common cause failures. It must be emphasized that the proposal is independent of any tool to evaluate quantitatively the target metrics. However, due to validation issues it was used a tool widely accepted on academy for this purpose (SHARPE). In addition, an algorithm to generate the minimal cut sets, originally applied on graph theory, was adapted to fault tree formalism to guarantee the scalability of methodology in wireless industrial network environments (< 100 devices). Finally, the proposed methodology was validate from typical scenarios found in industrial environments, as star, line, cluster and mesh topologies. It was also evaluated scenarios with common cause failures and best practices to guide the design of an industrial wireless network. For guarantee scalability requirements, it was analyzed the performance of methodology in different scenarios where the results shown the applicability of proposal for networks typically found in industrial environments

Implementação de duas arquiteturas microcontroladas tolerantes a falhas para controle da temperatura

Pós-graduação em Física - IGCE

Modelagem da disponibilidade de uma unidade geradora da UHE-Tucuruí

Com o advindo do marco regulatório do Setor Elétrico Brasileiro, a partir de 2004, os agentes que atuam neste mercado têm experimentado um acirramento nas disputas por novos negócios, evidenciando um aumento de competitividade. A Disponibilidade dos Ativos Físicos e os Custos com Manutenção se apresentam como os pontos chave para a competitividade dos agentes. O presente trabalho tem por objetivo apresentar uma metodologia de Análise de Disponibilidade de Sistemas Reparáveis, durante as etapas de projeto ou de operação do sistema, contemplando a mensuração dos Custos com Manutenção versus o Desembolso com Aquisição para um nível esperado de desempenho. A metodologia para a Análise de Disponibilidade sugerida se utiliza da construção do Diagrama de Blocos do Sistema com respectivas descrições funcionais, exportação das informações para o formato de Árvore de Sucesso, composta de portas lógicas dos tipos "E" e "OU" as quais caracterizam um subsistema integrante do sistema principal. O analista pode reavaliar a topologia do sistema, agregando ou retirando redundâncias com a finalidade de ajustar o desempenho do projeto aos requisitos de Disponibilidade, Custo de Aquisição e Custos de Manutenção. Como resultados do trabalho foram identificadas lacunas normativas que definem a forma de controle do desempenho dos ativos, estabelecida uma sistemática de integração entre técnicas de modelagem de confiabilidade e disponibilidade, estabelecidos e incorporados indicadores de desempenho de Manutenção Programada em um agente do mercado, foram modelados e discutidos diferentes cenários para um Sistema de Circulação de Óleo de Mancal e foi aplicado o modelo a toda uma Unidade Geradora Hidráulica por meio da implementação computacional do modelo aos componentes críticos dos principais sistemas.

Disponibilidade em um sistema de arquivos distribuído flexível e adaptável

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A QoS Controller Framework Compliant with the ETSI Network Function Virtualization Specification

The 5th generation of mobile networking introduces the concept of “Network slicing”, the network will be “sliced” horizontally, each slice will be compliant with different requirements in terms of network parameters such as bandwidth, latency. This technology is built on logical instead of physical resources, relies on virtual network as main concept to retrieve a logical resource. The Network Function Virtualisation provides the concept of logical resources for a virtual network function, enabling the concept virtual network; it relies on the Software Defined Networking as main technology to realize the virtual network as resource, it also define the concept of virtual network infrastructure with all components needed to enable the network slicing requirements. SDN itself uses cloud computing technology to realize the virtual network infrastructure, NFV uses also the virtual computing resources to enable the deployment of virtual network function instead of having custom hardware and software for each network function. The key of network slicing is the differentiation of slice in terms of Quality of Services parameters, which relies on the possibility to enable QoS management in cloud computing environment. The QoS in cloud computing denotes level of performances, reliability and availability offered. QoS is fundamental for cloud users, who expect providers to deliver the advertised quality characteristics, and for cloud providers, who need to find the right tradeoff between QoS levels that has possible to offer and operational costs. While QoS properties has received constant attention before the advent of cloud computing, performance heterogeneity and resource isolation mechanisms of cloud platforms have significantly complicated QoS analysis and deploying, prediction, and assurance. This is prompting several researchers to investigate automated QoS management methods that can leverage the high programmability of hardware and software resources in the cloud.

An Autonomic Framework for Mobile Cloud Computing

This thesis presents the formal definition of a novel Mobile Cloud Computing (MCC) extension of the Networked Autonomic Machine (NAM) framework, a general-purpose conceptual tool which describes large-scale distributed autonomic systems. The introduction of autonomic policies in the MCC paradigm has proved to be an effective technique to increase the robustness and flexibility of MCC systems. In particular, autonomic policies based on continuous resource and connectivity monitoring help automate context-aware decisions for computation offloading. We have also provided NAM with a formalization in terms of a transformational operational semantics in order to fill the gap between its existing Java implementation NAM4J and its conceptual definition. Moreover, we have extended NAM4J by adding several components with the purpose of managing large scale autonomic distributed environments. In particular, the middleware allows for the implementation of peer-to-peer (P2P) networks of NAM nodes. Moreover, NAM mobility actions have been implemented to enable the migration of code, execution state and data. Within NAM4J, we have designed and developed a component, denoted as context bus, which is particularly useful in collaborative applications in that, if replicated on each peer, it instantiates a virtual shared channel allowing nodes to notify and get notified about context events. Regarding the autonomic policies management, we have provided NAM4J with a rule engine, whose purpose is to allow a system to autonomously determine when offloading is convenient. We have also provided NAM4J with trust and reputation management mechanisms to make the middleware suitable for applications in which such aspects are of great interest. To this purpose, we have designed and implemented a distributed framework, denoted as DARTSense, where no central server is required, as reputation values are stored and updated by participants in a subjective fashion. We have also investigated the literature regarding MCC systems. The analysis pointed out that all MCC models focus on mobile devices, and consider the Cloud as a system with unlimited resources. To contribute in filling this gap, we defined a modeling and simulation framework for the design and analysis of MCC systems, encompassing both their sides. We have also implemented a modular and reusable simulator of the model. We have applied the NAM principles to two different application scenarios. First, we have defined a hybrid P2P/cloud approach where components and protocols are autonomically configured according to specific target goals, such as cost-effectiveness, reliability and availability. Merging P2P and cloud paradigms brings together the advantages of both: high availability, provided by the Cloud presence, and low cost, by exploiting inexpensive peers resources. As an example, we have shown how the proposed approach can be used to design NAM-based collaborative storage systems based on an autonomic policy to decide how to distribute data chunks among peers and Cloud, according to cost minimization and data availability goals. As a second application, we have defined an autonomic architecture for decentralized urban participatory sensing (UPS) which bridges sensor networks and mobile systems to improve effectiveness and efficiency. The developed application allows users to retrieve and publish different types of sensed information by using the features provided by NAM4J's context bus. Trust and reputation is managed through the application of DARTSense mechanisms. Also, the application includes an autonomic policy that detects areas characterized by few contributors, and tries to recruit new providers by migrating code necessary to sensing, through NAM mobility actions.

Modelagem semântica de processos industriais com aplicações

The main hypothesis of this thesis is that the deve lopment of industrial automation applications efficiently, you need a good structuri ng of data to be handled. Then, with the aim of structuring knowledge involved in the contex t of industrial processes, this thesis proposes an ontology called OntoAuto that conceptua lly models the elements involved in the description of industrial processes. To validat e the proposed ontology, several applica- tions are presented. In the first, two typical indu strial processes are modeled conceptually: treatment unit DEA (Diethanolamine) and kiln. In th e second application, the ontology is used to perform a semantic filtering alarms, which together with the analysis of correla- tions, provides temporal relationships between alar ms from an industrial process. In the third application, the ontology was used for modeli ng and analysis of construction cost and operation processes. In the fourth application, the ontology is adopted to analyze the reliability and availability of an industrial plant . Both for the application as it involves costs for the area of reliability, it was necessary to create new ontologies, and OntoE- con OntoConf, respectivamentem, importing the knowl edge represented in OntoAuto but adding specific information. The main conclusions of the thesis has been that on tology approaches are well suited for structuring the knowledge of industrial process es and based on them, you can develop various advanced applications in industrial automat ion.

Metodologia para análise da dependabilidade de Smart Grids

Smart Grids are a new trend of electric power distribution, the future of current systems. These networks are continually being introduced in order to improve the reliability of systems, providing alternatives to energy supply and cost savings. Faced with increasing electric power grids complexity, the energy demand and the introduction of alternative sources to energy generation, all components of system require a fully integration in order to achieve high reliability and availability levels (dependability). The systematization of a Smart Grid from the Fault Tree formalism enable the quantitative evaluation of dependability of a specific scenario. In this work, a methodology for dependability evaluation of Smart Grids is proposed. A study of case is described in order to validate the proposal. With the use of this methodology, it is possible to estimate during the early design phase the reliability, availability of Smart Grid beyond to identify the critical points from the failure and repair distributions of components.