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991.
Numerous experiments in job enlargement, direct worker participation and autonomous workgroups have been reported. However, little cumulative knowledge has been gained through a lack of conceptual and theoretical bases. Moreover, worker autonomy and technology, the major variables in those experiments either were measured by questioning workers and supervisors and are consequently modified by their perception, or were measured in a very broad fashion. In the present work more objective and specific measures for technology and autonomy, which can link job design research and experiments with job design practice, were developed and validated. Automony and technology are of course multidimensional concepts. Relevant aspects for job design are derived from a model for task related decision making which shows that the degree of worker autonomy is contingent on task technology and worker characteristics. Technology is measured by cycle time, task repetitiveness, task skill level, disturbance level of a task and the disruption potential of a task system, through observation. A distinction is made between autonomy in regulation, which keeps the process on target by counteracting disturbances and autonomy in control which specifies targets. Measures for both types of autonomy are developed. The measures of technology and autonomy were tested in a sample consisting of 411 work stations in industry and proved to be effective and efficient for job design purposes. 相似文献
992.
993.
994.
B. Roy U. Martinez K. Loganathan A.K. Datye C.A. Leclerc 《International Journal of Hydrogen Energy》2012
The effect of preparation method on the performance of Ni/Al2O3 catalysts for aqueous-phase reforming of ethanol (EtOH) has been investigated. The first catalyst was prepared by a sol–gel (SG) method and for the second one the Al2O3 support was made by a solution combustion synthesis (SCS) route and then the metal was loaded by standard wet impregnation. The catalytic activity of these catalysts of different Ni loading was compared with a commercial Al2O3 supported Ni catalyst [CM (10%)] at different temperatures, pressures, feed flow rates, and feed concentrations. Based on the product distribution, the proposed reaction pathway is a mixture of dehydrogenation of EtOH to CH3CHO followed by C–C bond breaking to produce CO + CH4 and oxidation of CH3CHO to CH3COOH followed by decarbonylation to CO2 + CH4. CH4(C2H6 and C3H8) also can form via Fischer–Tropsch reactions of CO/CO2 with H2. The CH4 (C2H6 and C3H8) reacts to form hydrogen and carbon monoxide through steam reforming, while CO converts to CO2 mostly through the water–gas shift reaction (WGSR). SG catalysts showed poorer WGSR activity than the SCS catalysts. The activation energies for H2 and CO2 production were 153, 155 and 167 kJ/mol and 158, 160 and 169 kJ/mol for SCS (10%), SG (10%), and CM (10%) samples, respectively. 相似文献
995.
J. Alonso F. Romero R. Pàmies-Vilà U. Lugrís J. M. Font-Llagunes 《Multibody System Dynamics》2012,28(1-2):109-124
Simulation of walking in individuals with incomplete spinal cord injuries (SCI) wearing an active orthosis is a challenging problem from both the analytical and the computational points of view, due to the redundant nature of the simultaneous actuation of the two systems. The objective of this work is to quantify the contributions of muscles and active orthosis to the net joint torques, so as to assist the design of active orthoses for SCI. The functional innervated muscles of SCI patients were modeled as Hill-type actuators, while the idle muscles were represented by elastic and dissipative elements. The orthosis was included as a set of external torques added to the ankles, knees, and hips to obtain net joint torque patterns similar to those of normal unassisted walking. The muscle-orthosis redundant actuator problem was solved through a physiological static optimization approach, for which several cost functions and various sets of innervated muscles were compared. 相似文献
996.
997.
In this paper the problem of selecting an optimal feedback controller, from a class of linear systems, for a non-linear dynamical system, is reduced to a standard parameter optimization problem given by Boltyanskii. A necessary condition for the selection of the optimal parameters is presented. 相似文献
998.
In this paper necessary conditions for optimal parameter selection of stochastic Ito differential systems are developed. Our main result, a necessary condition for optimality, is presented in theorem 1. Its proof is based on some recent results of Fleming (1968, p. 210), The result is illustrated by its application to the problem of determination of the optimal feedback gain matrix for a noisy linear regulator. 相似文献
999.
1000.
A robust and accurate road model estimation algorithm can greatly improve the performance of many Advanced Driver Assistance Systems applications such as lane detection, obstacle detection and road marking recognition. To estimate the road model, the proposed algorithm employs a stereo vision camera system. In this paper, local planar patches are efficiently estimated in the disparity domain rather than conventionally in the Euclidean domain. Then, the estimated planar patch orientations are integrated to the fitting stage, and orientation differences are minimized along with height differences. Moreover, patch orientation differences are exploited for weighting data points. Thus, outliers become insignificant in the fitting stage, and the road model is estimated robustly and accurately without any prior knowledge of any extrinsic camera parameters. Experiments have been carried out for a free space calculation application, and the road is segmented with a true positive rate (TPR) of 88 %. 相似文献