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71.
Safety-critical software systems such as certain nuclear instrumentation and control (NI&C) systems should be developed with thorough verification. This study presents a method of software requirement verification with a case study for a nuclear power plant (NPP) protection system. The verification introduces colored petri net (CPN) for system modeling and prototype verification system (PVS) for mathematical verification. In order to aid flow-through from modeling by CPN to mathematical proof by PVS, an information extractor from CPN models has been developed in this paper. In order to convert the extracted information to the PVS specification language, a translator has also been developed. This combined method has been applied to the functional requirements of the Wolsong NPP Shut Down System #2 (SDS2); logical properties of the requirements were verified. Through this research, guidelines and a tool support for the use of formal methods have been developed for application to NI&C software verification. 相似文献
72.
Young-Geun Han Sang Hyuck Kim Sang Bae Lee Un-Chul Paek Youngjoo Chung 《Electronics letters》2003,39(15):1107-1108
A novel fabrication method of the core mode blocker by exposing H/sub 2/-loaded Ge-B codoped fibres to local electric arc discharge for application to the LPFGs-based tunable all-fibre bandpass filter with 6.5 nm bandwidth and 40 nm tuning range is presented. 相似文献
73.
叠前地震数据优化处理技术分析 总被引:13,自引:6,他引:7
由于叠前时间偏移成像是在叠前数据上进行的,因此对数据的质量要求较高。针对这一问题进行了数据优化处理技术研究,研究的基础资料是胜利油田渤深6区块的三维地震数据,首先对资料的质量进行了分析一由于是拼接资料,因此存在着能量不均衡、覆盖次数不均匀、坡形不一致以及各类干扰发育等问题;然后针对这些问题研究了时间-空间域内分频随机噪声衰减、频率一空间域相干噪声衰减、波形匹配处理和数据拟合三维随机噪声衰减等4种处理方法,分别取得了很好的处理效果;在对实际资料进行数据优化处理时,根据资料的特点采用了合适的组合方式,处理后资料的品质得到了较大提高,相干噪声、随机噪声得到了有效衰减,波形一致性得到了恢复,中、深层有效频率和有效能量得到了加强。 相似文献
74.
改性乳化沥青的发展和应用概况 总被引:1,自引:0,他引:1
综述了改性乳化沥青的发展及应用概况,重点讨论了改性乳化沥青的生产、制备工艺、稳定性影响因素,并对国内外改性乳化沥青的应用情况加以概述。 相似文献
75.
76.
论文提出了一种混沌通信系统的噪音衰减算法,该算法利用混沌同步现象在接收端获得正确的噪音估计值,从而从接收信号中滤除噪音恢复出正确的信号。通过数值仿真试验表明该方法是可行的。 相似文献
77.
论文将Fermat素性检验的思想运用于不可约多项式的判断,给出了一个对于不可约判断问题的Monte Carlo 算法,分析了该算法的计算复杂度问题,并且给出了次数在200以内的检验结果。 相似文献
78.
With the creation of a pattern recognition system for metal transfer mode, this article has collected five kinds of spectrum signals in gas metal arc welding (MIG, MAG and CO2) and take them as training samples. These samples have been pretreated by computer, several key characteristic parameters of the spectrum signal have been creatively extracted, and a corresponding recognition function and a minimum-distance-classifier have been constructed. The results show that the pattern recognition of several kinds of metal transfer modes for the metal gas arc welding can be done successfully, and relative important parameters in welding process, such as the frequency of droplet transfer and the approximate diameter of each droplet, can also be obtained. 相似文献
79.
Mining constrained gradients in large databases 总被引:1,自引:0,他引:1
Dong G. Han J. Lam J.W.M. Pei J. Wangm K Zou W. 《Knowledge and Data Engineering, IEEE Transactions on》2004,16(8):922-938
Many data analysis tasks can be viewed as search or mining in a multidimensional space (MDS). In such MDSs, dimensions capture potentially important factors for given applications, and cells represent combinations of values for the factors. To systematically analyze data in MDS, an interesting notion, called "cubegrade" was recently introduced by Imielinski et al. [2002], which focuses on the notable changes in measures in MDS by comparing a cell (which we refer to as probe cell) with its gradient cells, namely, its ancestors, descendants, and siblings. We call such queries gradient analysis queries (GQs). Since an MDS can contain billions of cells, it is important to answer GQs efficiently. We focus on developing efficient methods for mining GQs constrained by certain (weakly) antimonotone constraints. Instead of conducting an independent gradient-cell search once per probe cell, which is inefficient due to much repeated work, we propose an efficient algorithm, LiveSet-Driven. This algorithm finds all good gradient-probe cell pairs in one search pass. It utilizes measure-value analysis and dimension-match analysis in a set-oriented manner, to achieve bidirectional pruning between the sets of hopeful probe cells and of hopeful gradient cells. Moreover, it adopts a hypertree structure and an H-cubing method to compress data and to maximize sharing of computation. Our performance study shows that this algorithm is efficient and scalable. In addition to data cubes, we extend our study to another important scenario: mining constrained gradients in transactional databases where each item is associated with some measures such as price. Such transactional databases can be viewed as sparse MDSs where items represent dimensions, although they have significantly different characteristics than data cubes. We outline efficient mining methods for this problem. 相似文献
80.