Automated 3D Vision Tracking for Project Control Support

On-site tracking in open construction sites is often difficult because of the large amounts of items that are present and need to be tracked. Additionally, the amounts of occlusions/obstructions present create a highly complex tracking environment. Existing tracking methods are based mainly on Radio Frequency technologies, including Global Positioning Systems (GPS), Radio Frequency Identification (RFID), Bluetooth and Wireless Fidelity (Wi-Fi, Ultra-Wideband, etc). These methods require considerable amounts of pre-processing time since they need to manually deploy tags and keep record of the items they are placed on. In construction sites with numerous entities, tags installation, maintenance and decommissioning become an issue since it increases the cost and time needed to implement these tracking methods. This paper presents a novel method for open site tracking with construction cameras based on machine vision. According to this method, video feed is collected from on site video cameras, and the user selects the entity he wishes to track. The entity is tracked in each video using 2D vision tracking. Epipolar geometry is then used to calculate the depth of the marked area to provide the 3D location of the entity. This method addresses the limitations of radio frequency methods by being unobtrusive and using inexpensive, and easy to deploy equipment. The method has been implemented in a C++ prototype and preliminary results indicate its effectiveness

Exploration de la dynamique entre les demandes, ressources au travail et la santé psychologique au travail.

Plusieurs interventions visant à améliorer la santé psychologique au travail reposent sur une conceptualisation pathogénique où celle-ci est représentée par une absence d’états psychologiques négatifs (Randall & Nielsen, 2010). Or, elle représenterait à la fois l’absence d’états négatifs de détresse psychologique au travail et la présence d’états positifs de bien-être psychologique au travail (Gilbert, Dagenais-Desmarais, & Savoie, 2011). Ceci suggère qu’afin de maximiser l’impact des interventions, il serait pertinent d’indiquer aux intervenants des leviers pouvant influencer les volets positifs et négatifs de la santé psychologique au travail. Parmi ces leviers, Gilbert (2009) a identifié les demandes et les ressources au travail. Cependant, les modèles théoriques traitant de l’impact de demandes et de ressources sur des états positifs et négatifs tendent à traiter de ces effets de manière indépendante et aucun ne formule de propositions concernant l’impact potentiel de ces leviers sur un état complet et unifié de santé psychologique au travail (e.g., Job Demand-Control(-Support) de Karasek & Theorell, 1990; Job Demands-Resources de Bakker & Demerouti, 2007). En considérant l’aspect interrelié et distinct de la facette positive et négative de la santé psychologique au travail, la présente thèse vise donc à explorer la dynamique entre les demandes, les ressources et un état complet et unifié de santé psychologique au travail. Pour ce faire, un article théorique et un article empirique sont présentés. L’article théorique intègre différentes théories afin d’apporter un éclairage sur l’incidence des demandes et ressources au travail sur un état complet et unifié de santé psychologique au travail, et d’expliquer simultanément l’influence de ces aspects du travail sur les facettes de bien-être et de détresse au travail. Il avance ainsi que, telles que définies par le modèle Job Demand-Resources (Bakker & Demerouti, 2007), les demandes tendraient a davantage représenter des menaces que des défis et auraient alors des effets néfastes sur un état complet de santé psychologique au travail et ses facettes positifs et négatifs. D’autre part, il est suggéré que lorsque les demandes sont élevées, avoir suffisamment de ressources pour se sentir capable de répondre avec succès aux demandes pourrait amener celles-ci à moins représenter des menaces et davantage représenter des défis. Comparativement à une situation où les ressources sont insuffisantes, cette première situation accroîtrait un état complet de santé psychologique au travail, de même que l’intensité de son volet positif, tandis que l’intensité de son volet négatif serait amoindrie. Enfin, il est suggéré que les ressources au travail faciliteraient la satisfaction des besoins psychologiques fondamentaux, ce qui aurait un effet bénéfique sur un état complet de santé psychologique au travail, de même que sur ses facettes. Pour sa part, l’article empirique vise à explorer empiriquement la dynamique entre les demandes, ressources et un état unifié et complet de santé psychologique au travail. Pour ce faire, deux études utilisant des modélisations par équations structurelles sont effectuées. La première utilise un devis transversal et deux échantillons de 302 et 384 enseignants. Elle montre que les demandes et ressources au travail ont une incidence directe respectivement nocive et bénéfique sur la santé psychologique au travail. Cependant, contrairement à ce qui était attendu, les ressources au travail n’auraient pas d’effet modérateur. Ces résultats sont similaires d’un échantillon à l’autre. La seconde étude utilise un devis longitudinal, deux temps de mesure avec une année d’intervalle et un échantillon de 158 enseignants. Suite à une comparaison des relations de causalité normale, inverse et réciproque; elle démontre que la causalité normale serait le type de relation qui expliquerait le mieux les données. Ce constat vient donc renforcer les résultats de l’étude précédente et suggère qu’une diminution des demandes et une augmentation des ressources s’accompagneraient d’une augmentation de la santé psychologique au travail. En explorant théoriquement et empiriquement la dynamique entre les demandes, les ressources et la santé psychologique au travail, la présente thèse offre des bases théoriques novatrices et des bases empiriques solides pour les recherches traitant de demandes et de ressources au travail qui désire étudier un état complet et unifié de santé psychologique au travail, et considérer l’aspect distinct et interdépendant de ses facettes positives et négatives. En pratique, une telle approche permettrait aux décideurs de plus facilement identifier les leviers sur lesquels il importe d’investir pour maximiser la santé psychologique, car cette dernière serait représentée par un critère unique plutôt que plusieurs critères séparés (Mihalopoulos, Carter, Pirkis, & Vos, 2013).

Work characteristics and employee outcomes in local government

The overall objective of this study was to examine the work characteristics that make significant contributions to extra-role performance (as measured by the helping dimension of citizenship behaviour) and employee wellbeing (measured by job satisfaction and psychological health) in a local government. The work characteristics examined were based on the demand-control-support (DCS) model, augmented by organization-specific characteristics. The results indicate that characteristics described in the core DCS are just as relevant to extra-role performance as they are to more traditional indicators of job stress. Although the more situation-specific conditions were not predictive of citizenship behaviour, they made unique contributions to job satisfaction

Combating the impact of managerialism on public sector employees

With the widespread and continuing adoption of managerialism in the public sector, ignoring the impact of change on employees could prevent managerialism from achieving its’ goals. This study investigates the efficacy of an augmented demand-control-support (D-C-S) model in predicting three of the key employee outcomes associated with organisational change - psychological health, job satisfaction and organisational commitment. Analyses of a survey of 207 employees in an Australian public sector organisation found that the augmented D-C-S model explained a significant proportion of the employee outcomes. The most important variables were work-based social support and job control. The results indicate that the augmented D-C-S model provides a useful tool for managers considering or implementing organisational change in the public sector.

Predictors of wellbeing experienced by Australian police officers

The aim of this study was to assess the ability of the Demand-Control-Support (DCS) model as well as the psychological contract model (PCM) to predict the wellbeing experienced by 2,566 Australian police officers. While the level of explained variance attributed to the PCM was substantially less than the DCS, measures of contract breach and organisational fairness still captured significant portions of intrinsic and extrinsic job satisfaction. Overall, the results of this study suggest that both the DCS and the PCM should figure prominently in strategies aimed at reducing or preventing police stress.

The work conditions of allied health professionals : the impact on satisfaction, commitment and psychological distress

The present study investigated the extent to which the Demand-Control-Support (DCS) model, in combination with organizational justice variables, predicts the employee-level outcomes of allied health professionals'. Allied health professionals from an Australian healthcare organization were surveyed, with 113 participating (52,6%). Multiple regression analyses revealed that the DCS model predicted all the outcome variables of job satisfaction, organizational commitment and psychological distress. Conversely, significant contributions of the organizational justice variables were limited to organizational commitment and psychological distress. The results of the study provide practical implications for the job conditions of allied health professionals, in particular, the delivery of support and maintaining high levels of justice.

Officer wellbeing, satisfaction and commitment : job conditions of Australian law enforcement personnel

Excessive job stress caused by unreasonably high employer demands, low control over one's own work and limited support can have far-reaching effects for the individual, organisation and community. The present study sought to investigate the relationship between officer working conditions and their self-reported levels of wellbeing, satisfaction and commitment using a well-known job strss model, the demand-control-support (DCS) model. Using a large (N= 2085) sample of law enforcement personnel, findings indicated that social support from work sources was the best predictor, whilst job control and workload both had significant influences on levels of employee wellbeing, satisfaction and commitment. Additionally, non-linear relationships were found between workload and wellbeing and satisfaction, indicating that both high and low levels of workload can produce negative outcomes. The results have implications for job design and management training programs, particularly in reference to social support training and workload models.

Promoting health at work : the relevance of organizational justice

Research focusing on the relationship between organizational justice and health suggests that perceptions of fairness can make significant contributions to employee wellbeing. However studies examining the justice health relationship are only just emerging and there are several areas where further research is required, in particular, the uniqueness of the contributions made by justice and the extent to which the health effects can be explained by linear, non-linear and/or interactional models. The primary aim of the current study was to determine the main, curvilinear and interactive effects of job characteristics and organizational justice perceptions on psychological wellbeing and job satisfaction. Job characteristics were measured using the Demand-Control Support (DCS) model (Karasek & Theorell, 1990), while Colquitt's (2001) four justice dimensions (distributive, procedural, interpersonal and informational) were used to assess organizational justice. Hierarchical regression analyses found that in relation to psychological wellbeing, perceptions of justice did not add to the explanatory power of the DCS model. In contrast, organizational justice did account for unique variance in job satisfaction, the second measure of employee wellbeing. The results supported direct linear relationships between the psychosocial working conditions and the outcome measures. The implications of the results of this study, especially in terms of how working conditions should be managed in order to promote health, are discussed. Notably, the findings from the current study indicate that in addition to traditional job stressors, health promotion strategies should focus on perceptions of organizational justice and their relationships with health.

Predictors of the attitudinal and health outcomes of aged care nurses

This study examines the predictive capacity of the Demand-Control-Support (DCS) model in combination with organizational justice variables on attitudinal- and health-related outcomes for aged care nurses. Multiple regression analyses of aged care nurses (n=168) from a medium to large Australian healthcare organization. The DCS model explains the largest amount of variance across both the attitudinal and health outcomes with 27% of job satisfaction and 44% of organizational commitment, and 33% of psychological distress and 35% of wellbeing, respectively. Additional variance was explained by the justice variables for job satisfaction, organizational commitment and psychological distress. The addition of the organizational justice variables to the DCS model proved to be a valuable step in understanding the work conditions of aged care nurses. The inclusion of curvilinear effects clarified the potentially artefactual nature of certain interaction variables. The results provide practical implications for managers of aged care nurses in developing and maintaining levels of job control, support and fairness, as well as monitoring levels of job demands. The results particularly highlight the importance of the nurses’ supervisor.

Supervisors are central to work characteristics affecting nurse outcomes

Purpose: To examine the predictive capability of the demand-control-support (DCS) model, augmented by organizational justice variables, on attitudinal- and health-related outcomes for nurses caring for elderly patients.

Design: The study is based on a cross-sectional survey design and involved 168 nurses working with elderly patients in facilities of a medium to large Australian organization.

Method: Participants were asked to complete a questionnaire consisting of scales designed for measuring independent (e.g., demand, control, support, organizational justice) and dependent (e.g., job satisfaction, organizational commitment, wellbeing and psychological distress) variables. Multiple regression analyses were undertaken to identify significant predictors of the outcome variables.

Findings: The DCS model explains the largest amount of variance across both the attitudinal and health outcomes with 27% of job satisfaction and 49% of organizational commitment, and 33% of psychological distress and 35% of wellbeing, respectively. Additional variance was explained by the justice variables for job satisfaction (5%), organizational commitment (4%), and psychological distress (23%).

Conclusions: Using organizational justice variables to augment the DCS model was valuable in better understanding the work conditions experienced by nurses caring for elderly patients. Inclusion of curvilinear effects added clarity to the potentially artifactual nature of certain interaction variables.

Clinical Relevance: The results indicated practical implications for managers of nurses caring for elderly patients in terms of developing and maintaining levels of job control, support, and fairness, as well as monitoring levels of job demands. The results particularly show the importance of nurses' immediate supervisors.