O modelo demanda e controle de Karasek, elaborado na década de 1970, postula que os trabalhadores expostos a situações de alta exigência no trabalho, decorrente da combinação entre altas demandas psicológicas e baixo controle sobre o processo de trabalho, tem maior risco de apresentar eventos em saúde relacionados ao estresse, em particular doenças cardiovasculares. Os objetivos desta tese incluíram: avaliar propriedades psicométricas do instrumento Demand-Control-Support Questionnaire (DCSQ) e conduzir uma meta-análise dos estudos publicados sobre a associação entre alta exigência no trabalho e hipertensão arterial. Três artigos foram elaborados. O primeiro artigo avaliou a validade dimensional e consistência interna da versão brasileira do instrumento DCSQ, quando aplicado a trabalhadores de um hospital e nove restaurantes no Rio de Janeiro. O segundo artigo comparou as propriedades psicométricas do DCSQ no contexto dos trabalhadores de hospital no Brasil e na Suécia. O terceiro artigo apresentou uma meta-análise dos estudos de associação entre alta exigência no trabalho e hipertensão arterial. Os resultados evidenciaram que o instrumento DCSQ tem estrutura tridimensional e equivalente nas versões brasileira e sueca (original), representada por demandas psicológicas, uso de habilidades e autonomia para a decisão. O modelo de melhor ajuste excluiu a dimensão apoio social no trabalho e o item trabalho repetitivo (uso de habilidades). A meta-análise revelou que os estudos foram heterogêneos, a população-alvo foi restrita a países da Europa, EUA e Japão, sem evidência de associação entre alta exigência no trabalho, demanda e controle, e hipertensão arterial. / Proposed in the 1970s, the demand control model stated that workers in high strain jobs, a combination of high levels of psychological demands and low levels of control, have an increased risk of stress-related outcomes, particularly cardiovascular diseases. The aim of this thesis is to evaluate the psychometric properties of the Demand-Control-Support Questionnaire (DCSQ) and to conduct a meta-analysis of published studies about the association of job strain and hypertension. Three articles were presented. The first article evaluated the dimensional validity and internal consistency of the Brazilian version of DCSQ, when applied to hospital and restaurant workers in Rio de Janeiro. The second article compared the psychometric properties of the Swedish and Brazilian versions of DCSQ, when applied to hospital workers. The third article presented a meta-analysis of the association studies of job strain and hypertension. The results evidenced a three-factor structure of the DCSQ, which was equivalent in the Brazilian and Swedish versions and closely related to psychological demands, skill discretion and decision authority dimensions. The best fit model was achieved by excluding the social support at work dimension and the item repetitive work (skill discretion). The meta-analysis revealed no association between high strain, and related dimensions, and hypertension in samples restricted to European countries, USA and Japan, in which heterogeneity between studies was evidenced.

The purpose of the project, which led to this thesis, was to investigate the possible effects different horizontal Fields of View (FoV) have on driving performance when driving at night with a Vision Enhancement System (VES). The FoV chosen to be examined were 12 degree and 24 degree FoV, both displayed on a screen with the horizontal size of 12 degree FoV. This meant that the different conditions of FoV also had different display ratios 1:1 and 1:2. No effort was made to separate these parameters. A simulator study was performed at the simulator at IKP, Linköping University. Sixteen participants in a within-group design participated in the study. The participants drove two road sections; one with a 12 degree FoV and the other with a 24 degree FoV. During each section four scenarios were presented in which the participants passed one of three types of objects; a moose, a deer or a man. In each section, two of the objects stood right next to the road and two were standing seventeen meters to the right of the road. As the drivers approached the objects standing seventeen meters to the right of the road, the objects moved out of the VES when the vehicle was 200 meters in front of the object with a 12 degree FoV. The objects could be seen with the naked eye when the vehicle was 100 meters in front of the object. When the drivers approached the objects with a 24degree FoV the objects moved out of the VES display when it was possible to see them unaided. Results show that a 24 degree FoV displayed with a 1:2 ratio gives the drivers improved anticipatory control, compared to a 12 degree FoV displayed with a 1:1 ratio. The participants with a broader FoV were able to make informed decisions whereas with a narrow FoV some participants started to reaccelerate when they could not see an object. Results also show that any difference in recognition distance that may exist between a 12 degree and a 24 degree camera angle displayed in a 12 degree FoV display do not seem to have any adverse effect on the quality of driving.

Denna magisteruppsats redogör för en anpassning av COCOM (Contextual Control Model) till flygledningsdomänen. COCOM är en modell som kan användas för att beskriva och förutse kontroll hos operatörer i komplexa system. En central del av modellen är begreppet kontrollnivå vilket beskriver hur graden av kontroll hos ett JCS (Joint Cognitive System) beror av och påverkar de parametrar som beskriver dess prestation. Fokus i denna uppsats ligger på det JCS som omfattar flygledaren i sin arbetsposition. I uppsatsen anpassas Hollnagels generella beskrivning av kontrollnivåer i COCOM till flygledningsdomänen. Till grund för anpassningen ligger en kvalitativ studie i form av observation och intervju av sju operativa flygledare vid en svensk kontrollcentral. De tre parametrarna målavvägning, subjektivt tillgänglig tid samt planering och prioritering befinns särskilt lämpliga för att beskriva kontroll inom flygledning. I uppsatsen identifieras också, med utgångspunkt i resilience engineering, tolv strategier som flygledare använder för att bibehålla kontroll i det vardagliga arbetet. Två exempel på strategier är att anpassa sig till kollegor och deras arbetssituation, samt användandet av ”extra ögon”, att låta en kollega övervaka arbetet. Valet av strategi kopplas i uppsatsen samman med vilken kontrollnivå flygledaren befinner sig på. Domänanpassningen av COCOM visar att modellen är lämplig för modellering av operatörer. COCOM för flygledning kan användas för att bättre klassificera prestation specifikt inom detta område, samt som stöd i samband med utvecklandet av nya verktyg och arbetsmetoder. Kunskap om kontrollstrategier kan med fördel utnyttjas vid utbildning av flygledare, som med denna typ av metakunskap kan få mer medvetna verktyg för att bibehålla kontroll.

Driver psychology is one of the most difficult phenomena to model in the realm of traffic flow theory because mathematics often cannot capture the human factors involved with driving a car. Over the past several decades, many models have attempted to model driver aggressiveness with varied results. The recently proposed Longitudinal Control Model (LCM) makes such an attempt, and this paper offers evidence of the LCM's usefulness in modeling road dynamics by analyzing deceleration rates that are commonly associated with various levels of aggression displayed by drivers. The paper is roughly divided into three sections, one outlining the LCM's ability to quantify forces between passive and aggressive drivers on a microscopic level, one describing the LCM's ability to measure aggressiveness of platoons of drivers, and the last explaining the meaning of the model’s derivative. The paper references some attempts to capture driver aggressiveness made by classic car-following models, and endeavors to offer some new ideas in study of driver characteristics and traffic flow theory.

No description available.

No description available.

Teachers’ work-related health has worsened in Sweden, seen in the rising number of teachers who are stressed, unmotivated and that have left work or are on sick leave (The Swedish National Agency for Education, 2013; Månsson, 2008). The thesis’s aim was to explore the relation between health, personal coping and job stress. As proposed by Antonovsky (1979; 1987), sense of coherence (SOC) was used as an important individual approach for Salutogenesis; health maintenance. Health was measured as self-reported health and job stress according to the demand-control model (DCM) by Karasek (1979). Data came from the Teacher survey, a questionnaire part of a larger research project based at the Centre for Health and Equity Studies, Stockholm University/Karolinska Institutet, focused on school environment and health for pupils and teachers. The analytical sample consisted of teachers teaching 7-9th grade (n=1092), from both private and public schools. Results indicate an association for SOC and DCM independently with self-rated health, as well as a strong role for SOC in decreasing the odds of having less than good health due to psychosocial working conditions, especially for teachers who perceive their jobs as highly demanding.

Syftet med denna studie var att få en inblick i arbetsmiljön för socialsekreterare på socialtjänstens enhet för barn- och ungdom inom Stockholms län. Vi ville även ta reda på vilka arbetsmiljöaspekter de tycker är viktiga för det dagliga arbetet. Tidigare forskning visar att viktiga aspekter vid tankar om att lämna sitt arbete är huruvida arbetstagaren upplever uppskattning, omhändertagande och intresse för hälsa och välmående från arbetsledningen. Studien är genomförd utifrån en kvalitativ ansats och sju semistrukturerade intervjuer med socialsekreterare inom barn- och ungdom har utförs. Resultatet visade att socialsekreterare skiljer mellan den fysiska och den psykiska arbetsmiljön samt att den psykiska arbetsmiljön väger tyngre gällande frågan om att vilja lämna sin arbetsplats. Vidare visade sig arbetsmiljön vara ett komplex ämne som ofta diskuteras på informanternas arbetsplatser samtidigt som ingen av våra informanter hade hört om de nya föreskrifterna från Arbetsmiljöverket. Då de nya föreskrifterna trädde i kraft i samband med att denna uppsats skrevs hoppas vi ändå att de ska kunna föra med sig en bra grund i arbetet för en bättre arbetsmiljö. Slutligen kan det finnas en poäng i att rikta de allmänna råden även till arbetstagarna och inte endast till arbetsgivaren, för att på så sätt engagera arbetstagarna ytterligare i frågan. / The aim of this study was to getting an insight of the work enviorment for the social workers at the social service department for child and youth welfare in Stockholm. We also wanted to get an insight into what kind of work enviorment factors they consider as important in their daily work. Previous research shows that whether or not the employee decides to stay in their place of work largely depends whether or not they experience appreciation, care-taking and involvement from the human resources managment. This study is made with a qualitative approach and seven semi-structured interviews with social workers working with child and youth welfare have been conducted. The results show that social workers differed in how they perceived the physical and psychological work environment and that the psychological aspect was more important for those social workers who wished to leave the workplace. Furthermore, the results showed that the work environment was a subject widely discussed among the social workers, while the new regulations from the Swedish work environment agency remained unknown to them. We hope that the new regulations will provide a good foundation and better conditions for the social workers and their work environment. In conclusion, we think that the general recommendations in these regulations ought to be directed not only to the employers but to the employees as well, thus achieving a greater involvement from the employees in questions concerning their work environment.

A robust model predictive control algorithm is presented that explicitly handles multiplicative, or parametric, uncertainty in linear discrete models over a finite horizon. The uncertainty in the predicted future states and inputs is bounded by polytopes. The computational cost of running the controller is reduced by calculating matrices offline that provide a means to construct outer approximations to robust constraints to be applied online. The robust algorithm is extended to problems of uncertain models with an allowed probability of violation of constraints. The probabilistic degrees of satisfaction are approximated by one-step ahead sampling, with a greedy solution to the resulting mixed integer problem. An algorithm is given to enlarge a robustly invariant terminal set to exploit the probabilistic constraints. Exponential basis functions are used to create a Robust MPC algorithm for which the predictions are defined over the infinite horizon. The control degrees of freedom are weights that define the bounds on the state and input uncertainty when multiplied by the basis functions. The controller handles multiplicative and additive uncertainty. Robust MPC is applied to the problem of wind turbine control. Rotor speed and tower oscillations are controlled by a low sample rate robust predictive controller. The prediction model has multiplicative and additive uncertainty due to the uncertainty in short-term future wind speeds and in model linearisation. Robust MPC is compared to nominal MPC by means of a high-fidelity numerical simulation of a wind turbine under the two controllers in a wide range of simulated wind conditions.

Introdução - O ambiente psicossocial do trabalho em enfermagem influencia diretamente a qualidade de vida dos trabalhadores desta área. Diferenças entre as categorias profissionais nesta profissão podem se traduzir em diferenças na percepção de saúde e de condições de trabalho. Objetivo - Avaliar as associações entre condições de trabalho e qualidade de vida relacionada à saúde (QVRS) de enfermeiros, técnicos e auxiliares de enfermagem. Métodos Foram coletados dados em um hospital universitário no município de São Paulo, de uma população de 696 enfermeiros, técnicos e auxiliares de enfermagem, população predominantemente feminina (87,8%) e que trabalhava em turnos diurno e noturno. Os dados coletados a partir de questionário correspondiam a informações sobre aspectos sóciodemográficos, condições de trabalho e de vida, hábitos de vida e sintomas de saúde referidos desta população. Foram também utilizados os questionários: Questionário Genérico de Avaliação de Qualidade de Vida (SF-36), Escala de Estresse no Trabalho e Desequilíbrio Esforço-Recompensa (ERI). Foram ajustados modelos de regressão logística ordinal de chances proporcionais para cada dimensão do SF-36. Resultados Aproximadamente 22% da população foi classificada como trabalhando em condições de alto desgaste e 8% em desequilíbrio desfavorável entre esforços e recompensa no trabalho. Vitalidade, dor e saúde mental foram as dimensões do SF-36 com pior avaliação. Os modelos de regressão múltipla 5 demonstraram: alto comprometimento associado a todas as dimensões do SF-36, e ERI desfavorável associado a todas as dimensões relacionadas à saúde mental. Alto desgaste no trabalho, ERI desfavorável, alto comprometimento e ser enfermeira associaram-se de maneira independente aos resultados desfavoráveis da dimensão de aspectos emocionais. Conclusões As dimensões relacionadas à saúde mental foram as que mais sofreram influência dos fatores psicossociais do trabalho. ERI desfavorável e alto comprometimento mostraram-se mais significativos à saúde desta população comparados com altas demandas e baixo controle. Os resultados indicam que a análise conjunta dos modelos de desequilíbrio esforço-recompensa e demandacontrole contribui para a discussão sobre os papéis profissionais, condições de trabalho e QVRS de profissionais de enfermagem. / Introduction- The psychosocial work environment influences the quality of life of nursing professionals. Differences among job titles may lead to distinct perceptions of working conditions and health status. Aim-To evaluate working and living conditions and quality of life associated with health (HRQL) among nursing professionals. Methods- Six hundred ninety six nursing professionals, registered nurses and nurse assistants, predominantly females (87.8%), working day or night shifts, participated in a study carried out in an university hospital of São Paulo, Brazil. Data collection took place during 2004-2005 and included a comprehensive questionnaire including sociodemographic characteristics, life styles, working and living conditions, and health outcomes. HRQL was evaluated using the short form questionnaire of quality of life (SF-36). Working conditions included the job stress scale, effort-reward imbalance (ERI), and other environmental and occupational stressors. Ordinal logistic regression of proportional ratios was used to evaluate each of SF-36 dimensions. Results- Imbalance of the effort-reward ratio and high work strain were mentioned by 7.8% and 22.1% of the participants, respectively. Vitality, pain and (poor) mental health were the SF-36 worse perceived outcomes. The multiple regression models showed: over commitment associated with all SF-36 dimensions, and unfavorable ERI associated with mental health dimensions. High 7 job strain, unfavorable ERI, over commitment, and being a registered nurse were independently associated with negative emotional outcomes. Conclusions- The dimensions associated with mental health were significantly influenced by psychosocial factors at work. Unfavorable ERI and over commitment were more significantly associated with health compared to high demands and low control. These results show the importance to jointly evaluate ERI and demand- control models to discuss professional roles, working conditions and HRQL of nursing professionals.