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Acceptable Time (acceptable + time)
Selected AbstractsA case of rule-based heuristics for scheduling hot rolling seamless steel tube productionEXPERT SYSTEMS, Issue 3 2006Jianxiang Li Abstract: A production scheduling problem for hot rolling seamless steel tube at Tianjin Pipe Corporation of China is studied. Considering the complexity of the problem and the acceptable time for solving it, a rule-based heuristic approach is proposed and implemented. The proposed approach is a bottleneck scheduling method and considers simultaneously all production processes in three production units and ,optimizes' them as a whole. Additionally, the running result shows, on average, that a 3% increase in throughput and a 5% reduction in late deliveries have been achieved since the system implementation. [source] Isotropic resolution diffusion tensor imaging with whole brain acquisition in a clinically acceptable timeHUMAN BRAIN MAPPING, Issue 4 2002Derek Kenton Jones Abstract Our objective was to develop a diffusion tensor MR imaging pulse sequence that allows whole brain coverage with isotropic resolution within a clinically acceptable time. A single-shot, cardiac-gated MR pulse sequence, optimized for measuring the diffusion tensor in human brain, was developed to provide whole-brain coverage with isotropic (2.5 × 2.5 × 2.5 mm) spatial resolution, within a total imaging time of approximately 15 min. The diffusion tensor was computed for each voxel in the whole volume and the data processed for visualization in three orthogonal planes. Anisotropy data were further visualized using a maximum-intensity projection algorithm. Finally, reconstruction of fiber-tract trajectories i.e., ,tractography' was performed. Images obtained with this pulse sequence provide clear delineation of individual white matter tracts, from the most superior cortical regions down to the cerebellum and brain stem. Because the data are acquired with isotropic resolution, they can be reformatted in any plane and the sequence can therefore be used, in general, for macroscopic neurological or psychiatric neuroimaging investigations. The 3D visualization afforded by maximum intensity projection imaging and tractography provided easy visualization of individual white matter fasciculi, which may be important sites of neuropathological degeneration or abnormal brain development. This study has shown that it is possible to obtain robust, high quality diffusion tensor MR data at 1.5 Tesla with isotropic resolution (2.5 × 2.5 × 2.5 mm) from the whole brain within a sufficiently short imaging time that it may be incorporated into clinical imaging protocols. Hum. Brain Mapping 15:216,230, 2002. © 2002 Wiley-Liss, Inc. [source] Autocascade refrigeration system: Experimental results in achieving ultra low temperatureINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 6 2009C. Aprea Abstract In this paper the experimental results of an autocascade refrigeration system for achieving ultra low temperature are presented. The plant is used to preserve tissue and cells. When the air temperature is equal to ,150°C in 0.25,m3 space, the required refrigeration power is about 250,W. The influence of the most meaningful variables is discussed with regard to the design of the plant. The experimental results show an acceptable time to reach the steady state in dependence of the finality of the plant. The working substance is a non-azeotropic mixture consisting of hydrofluorocarbon (HFC) refrigerants in addition to argon and methane. Copyright © 2009 John Wiley & Sons, Ltd. [source] Rapid magnetic resonance quantification on the brain: Optimization for clinical usageMAGNETIC RESONANCE IN MEDICINE, Issue 2 2008J.B.M. Warntjes Abstract A method is presented for rapid simultaneous quantification of the longitudinal T1 relaxation, the transverse T2 relaxation, the proton density (PD), and the amplitude of the local radio frequency B1 field. All four parameters are measured in one single scan by means of a multislice, multiecho, and multidelay acquisition. It is based on a previously reported method, which was substantially improved for routine clinical usage. The improvements comprise of the use of a multislice spin-echo technique, a background phase correction, and a spin system simulation to compensate for the slice-selective RF pulse profile effects. The aim of the optimization was to achieve the optimal result for the quantification of magnetic resonance parameters within a clinically acceptable time. One benchmark was high-resolution coverage of the brain within 5 min. In this scan time the measured intersubject standard deviation (SD) in a group of volunteers was 2% to 8%, depending on the tissue (voxel size = 0.8 × 0.8 × 5 mm). As an example, the method was applied to a patient with multiple sclerosis in whom the diseased tissue could clearly be distinguished from healthy reference values. Additionally it was shown that, using the approach of synthetic MRI, both accurate conventional contrast images as well as quantification maps can be generated based on the same scan. Magn Reson Med 60:320,329, 2008. © 2008 Wiley-Liss, Inc. [source] | ||||||||||