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61.
A heterogeneous system or distributed system typically contains different types of processors. Some jobs can execute on certain types of processors but not other types. Processors of different types may have different speeds. We present several worst-case upper bounds and efficient algorithms for determining the completion times of independent jobs that have arbitrary timing constraints and variable execution times and are scheduled on available processors dynamically in a priority-driven manner. Bounds and algorithms take into account the effects of nonmigratability, nonpreemptability and different levels of migratability.  相似文献   
62.
The NearFar program is a package for carrying out an interactive nearside-farside decomposition of heavy-ion elastic scattering amplitude. The program is implemented in Java to perform numerical operations on the nearside and farside angular distributions. It contains a graphical display interface for the numerical results. A test run has been applied to the elastic scattering at Elab=1503 MeV.

Program summary

Title of program: NearFarCatalogue identifier: ADYP_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADYP_v1_0Program obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandLicensing provisions: noneComputers: designed for any machine capable of running Java, developed on PC-Pentium-4Operating systems under which the program has been tested: Microsoft Windows XP (Home Edition)Program language used: JavaNumber of bits in a word: 64Memory required to execute with typical data: case dependentNo. of lines in distributed program, including test data, etc.: 3484Number of bytes distributed program, including test data, etc.: 142 051Distribution format: tar.gzOther software required: A Java runtime interpreter, or the Java Development Kit, version 5.0Nature of physical problem: Interactive nearside-farside decomposition of heavy-ion elastic scattering amplitude.Method of solution: The user must supply a external data file or PPSM parameters which calculates theoretical values of the quantities to be decomposed.Typical running time: Problem dependent. In a test run, it is about 35 s on a 2.40 GHz Intel P4-processor machine.  相似文献   
63.
1引言 并联机器人具有输出精度高、结构刚性好、承载能力强、部件简单及运动学反解简单等许多串联机器人所没有的优点,近年来引起了机器人研究者的高度重视.其中,六自由度并联机器人方面的研究已比较深入和成熟.三自由度并联机器人是一种很有实用前景的机器人,也越来越多地引起人们的注意.三自由度并联机器人包括平面三自由度并联机器人,球面三自由度并联机器人和空间三自由度并联机器人.球面三自由度并联机器人能够实现运动平台三维转动,是一种角台形式,由静角台、动角台和三组具有一定弧度的连杆架和连杆构成,各联接处均采用转动副.这种机构结构复杂、设计困难。  相似文献   
64.
Recently, requests for accurate process planning using simulation have been increasing in many engineering fields, including the shipbuilding industry. To date, designers of shipyards have developed in-house simulation systems or used commercial systems such as the QUEST by Dassault system when requests for the simulation of process planning have occurred. However, these methods have some limitations. First, it requires a lot of time to develop a new in-house simulation system. In addition, it is hard to reuse previously developed systems when developing a new one and it is also hard for these to satisfy the various needs of shipyards effectively.  相似文献   
65.
This paper presents an automatic real-time video matting system. The proposed system consists of two novel components. In order to automatically generate trimaps for live videos, we advocate a Time-of-Flight (TOF) camera-based approach to video bilayer segmentation. Our algorithm combines color and depth cues in a probabilistic fusion framework. The scene depth information returned by the TOF camera is less sensitive to environment changes, which makes our method robust to illumination variation, dynamic background and camera motion. For the second step, we perform alpha matting based on the segmentation result. Our matting algorithm uses a set of novel Poisson equations that are derived for handling multichannel color vectors, as well as the depth information captured. Real-time processing speed is achieved through optimizing the algorithm for parallel processing on graphics hardware. We demonstrate the effectiveness of our matting system on an extensive set of experimental results.  相似文献   
66.
脉冲爆震发动机试验模型测控系统设计与实现   总被引:1,自引:0,他引:1  
针对新型推进系统脉冲爆震发动机试验模型的多通道高速采集和实时控制的要求,设计并实现了发动机的实时测控系统.并重点介绍了系统的软硬件体系结构以及抗干扰、网络通讯及数据库存储等关键技术;经实际应用表明。系统实时性强,可靠性高,满足试验模型对高速采集和控制时间的要求。  相似文献   
67.
68.
Bacterial Delta5-3-ketosteroid isomerase (KSI) catalyzes a stereospecific isomerization of steroid substrates at an extremely fast rate, overcoming a large disparity of pKa values between a catalytic residue and its target. The crystal structures of KSI from Pseudomonas putida and of the enzyme in complex with equilenin, an analogue of the reaction intermediate, have been determined at 1.9 and 2.5 A resolution, respectively. The structures reveal that the side chains of Tyr14 and Asp99 (a newly identified catalytic residue) form hydrogen bonds directly with the oxyanion of the bound inhibitor in a completely apolar milieu of the active site. No water molecule is found at the active site, and the access of bulk solvent is blocked by a layer of apolar residues. Asp99 is surrounded by six apolar residues, and consequently, its pKa appears to be elevated as high as 9.5 to be consistent with early studies. No interaction was found between the bound inhibitor and the residue 101 (phenylalanine in Pseudomonas testosteroni and methionine in P. putida KSI) which was suggested to contribute significantly to the rate enhancement based on mutational analysis. This observation excludes the residue 101 as a potential catalytic residue and requires that the rate enhancement should be explained solely by Tyr14 and Asp99. Kinetic analyses of Y14F and D99L mutant enzymes demonstrate that Tyr14 contributes much more significantly to the rate enhancement than Asp99. Previous studies and the structural analysis strongly suggest that the low-barrier hydrogen bond of Tyr14 (>7.1 kcal/mol), along with a moderate strength hydrogen bond of Asp99 ( approximately 4 kcal/mol), accounts for the required energy of 11 kcal/mol for the transition-state stabilization.  相似文献   
69.
Confocal immunofluorescence microscopy with anti-cytokeratin antibodies revealed a continuous and polarized network of cytokeratin (CK) filaments in the cortex of stage VI Xenopus oocytes. In the animal cortex, CK filaments formed a dense meshwork that both was thicker and exhibited a finer mesh than the network of CK filaments previously observed in the vegetal cortex (Klymkowsky et al., 1987). CK filaments first appeared in association with germinal vesicle (GV) and mitochondrial mass (MM) of oocytes in early mid stage I, indicating that CK filaments are the last of the three cytoskeletal networks to be assembled. By late stage I, CK filaments formed complex networks surrounding the GV, surrounding and penetrating the MM, and linking these networks to a meshwork of CK filaments in the oocyte cortex. During stage III-early IV, CK filaments formed a highly interconnected, apparently unpolarized, radial array linking the perinuclear and cortical CK filament networks. Polarization of the CK filament network was observed during mid stage IV-stage V, as first the animal, then the vegetal CK filament networks adopted the organization characteristic of stage VI oocytes. Treatment of stage VI oocytes with cytochalasin B disrupted the organization of both cortical and cytoplasmic CK filaments, releasing CK filaments from the oocyte cortex and inducing formation of numerous cytoplasmic CK filament aggregates. CB also disrupted the organization of cytoplasmic microtubules (MTs) in stage VI oocytes. Disassembly of oocyte MTs with nocodazole resulted in loss of the characteristic A-V polarity of the cortical CK filament network. In contrast, disruption of cytoplasmic CK filaments by microinjection of anti-CK antibodies had no apparent effect on cytoplasmic or MT organization. We propose a model in which the organization and polarization of the cortical network of CK filaments in stage VI Xenopus oocytes are dependent upon a hierarchy of interactions with actin filaments and microtubules.  相似文献   
70.
    
Subjective evaluations by experienced test drivers are primarily used to assess the driveability of vehicles in automotive companies. However, these evaluations are limited in terms of repeatability, incur costs, and require much time. Therefore, this study introduces a method of quantitatively evaluating the driveability of heavy-duty vehicles to circumvent these limitations. A vehicle experiment is conducted to measure data from an electronic control unit and an accelerometer to assess the driveability of heavy-duty vehicles. The evaluation indices for driveability are selected from previous studies on the objective and subjective methods of evaluating driveability according to various driving conditions. The indices include engine start, idle, acceleration, deceleration, constant speed, and start-up driving conditions. This research presents a quantitative evaluation method using the calculated values of each index and the correlated weighting factors of indices obtained from the regression analysis of the subjective evaluations. The driveability of heavy-duty vehicles is quantitatively evaluated under various driving conditions based on the proposed method. Results of the quantitative evaluation are similar to those of the subjective evaluations, and the proposed method is determined applicable in evaluating the driveability of heavy-duty vehicles.  相似文献   
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