32 research outputs found

    Path Planning with Modified a Star Algorithm for a Mobile Robot

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    AbstractThis article deals with path planning of a mobile robot based on a grid map. Essential assumption for path planning is a mobile robot with functional and reliable reactive navigation and SLAM. Therefore, such issues are not addressed in this article. The main body of the article introduces several modifications (Basic Theta*, Phi*) and improvements (RSR, JPS) of A star algorithm. These modifications are focused primarily on computational time and the path optimality. Individual modifications were evaluated in several scenarios, which varied in the complexity of environment. On the basis of these evaluations, it is possible to choose path planning method suitable for individual scenario

    Job stress and mortality in older age

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    Objectives: This paper aims to assess the relationship between the determinants of the psychosocial work environment, as expressed in terms of JDC or ERI models, and all-cause mortality in older individuals. Materials and Methods: The baseline study was conducted on a cohort comprising a random sample of 65-year-old community-dwelling citizens of Kraków, Poland. All of the 727 participants (410 women, 317 men) were interviewed in their households in the period between 2001 and 2003; a structured questionnaire was used regarding their occupational activity history, which included indexes measuring particular dimensions of their psychosocial work environment based on Karasek's Job Demand-Control model and Siegrist's Effort-Reward Imbalance model, as well as health-related quality of life and demographic data. Mortality was ascertained by monitoring City Vital Records for 7 years. Analyses were conducted separately for men and women, with the multivariate Cox proportional hazard model. Results: During a 7-year follow-up period, 59 participants (8.1%) died, including 21 women (5.1% of total women) and 38 men (12%) (p < 0.05). Significant differences in the number of deaths occurred regarding disproportion between physical demands and control in men: those with low physical demands and low control died three times more often than those with high control, regardless of the level of demands. The multivariate Cox proportional hazard model showed that significantly higher risk of death was observed only in men with low physical demands and low control, compared to those with low physical demands and high control (Exp(B) = 4.65, 95% CI: 1.64-13.2). Conclusions: Observed differences in mortality patterns are similar to the patterns of relationships observed in health-related quality of life (HRQoL) level at the beginning of old age; however, the relationship between efforts and rewards or demands and control and mortality was not fully confirmed

    Coordinated Movement of Multiple Robots in Outdoor Environment with Obstacles Pages

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    This article mainly focuses on the proposal of the program that coordinates the movement of multiple robots in outdoor environment. The emphasis of the proposed algorithm is on collision free movement. Simulation with four robots that are controlled in an environment with obstacles is the result of these experiments. The formation of robots consists of a leader and three following robots, which are trying to copy leader¢‚¬„¢s movement. Robots use GPS, laser rangefinder, as well as bumpers sensors for the environment scanning. GPS is used as positioning sensor and other sensors are used for reactive navigation. Besides that, simulation uses virtual reality from Microsoft Robotics Studio 4 (MRS). In addition, programming language used for this simulation is called Visual Programming Language. Advantage of MRS usage is that the final code can be simply transferred into real robots

    Ultrasonic Localization of Multiple Robots

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    In this work, we are focused on mathematic entity of localization by trilateration. Mathematical equations are usable for localization of source of ultrasonic waves. These can be measured in plane or 3D space by microphone array. We solve step-by-step localization by two, three and four sensors. Work also contains parts about localization without microphone array. For these measurements are used only distances between robots. We discuss about usability of ultrasonic, its advantages and necessity of temperature and humidity compensation

    IgG4-related sclerosing thyroiditis (Riedel-Struma): a review of clinicopathological features and management

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    We present a thorough review of the literature on Riedel thyroiditis (RT) with emphasis on aetiology, diagnosis and management, using the PubMed, Sinomed, and China National Knowledge Infrastructure databases. Although the exact aetiology of RT remains obscure, the histopathological features are consistent with a localized form of IgG4-related systemic disease (IgG4-RSD). Nevertheless, IgG4-RSD as a systemic fibroinflammatory disorder per se rarely affects the thyroid in the context of multiorgan manifestations. The initial diagnosis of RT is based on clinical history and imaging, but confirmation by histopathological examination is mandatory. In contrast to the historical surgical approach, glucocorticosteroid therapy is currently considered first line therapy, in line with the RT currently being viewed as a manifestation of, or analogous to, IgG4-RSD. For disease relapse, immunomodulatory agents (azathioprine, methotrexate, rituximab) can be used
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