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251.
1 引言 Leapfrog sCF具有低灵敏度特性。但在低通情况下,由于开关电容模拟输人电阻的近似性,使得Lcapfrog scF的灵敏度特性变差二。文献[2贻出了设计低灵敏度scF的状态空间法,描述了满足低灵敏度和零灵敏度的矩阵条件,·但未给出寻求满足一定条件的变换矩阵的系统方法。本文在文献口汹基础上,导出了具 相似文献
252.
操作系统是紧靠硬件的基础软件,它既是应用软件安全的坚实基础,又是硬件不安全因素的屏蔽器.在操作系统安全隐患和嵌入式操作系统技术特点的基础上,提出信息保护、空间域保护和时间域保护等增强操作系统安全性的几种方法,以提高嵌入式系统抗击系统本身缺陷或敌方恶意攻击等安全威胁的能力.上述几种安全保护技术已在嵌入式Linux中进行验证,并取得满意的结果. 相似文献
253.
Zhi-Long Chen 《海军后勤学研究》1998,45(3):279-295
We consider the parallel replacement problem in which machine investment costs exhibit economy of scale which is modeled through associating both fixed and variable costs with machine investment costs. Both finite- and infinite-horizon cases are investigated. Under the three assumptions made in the literature on the problem parameters, we show that the finite-horizon problem with time-varying parameters is equivalent to a shortest path problem and hence can be solved very efficiently, and give a very simple and fast algorithm for the infinite-horizon problem with time-invariant parameters. For the general finite-horizon problem without any assumption on the problem parameters, we formulate it as a zero-one integer program and propose an algorithm for solving it exactly based on Benders' decomposition. Computational results show that this solution algorithm is efficient, i.e., it is capable of solving large scale problems within a reasonable cpu time, and robust, i.e., the number of iterations needed to solve a problem does not increase quickly with the problem size. © 1998 John Wiley & Sons, Inc. Naval Research Logistics 45: 279–295, 1998 相似文献
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255.
人才引进工作是我军人才建设的重要环节。当前在人才引进中还有不少困难。应当正视在公民职业选择行为中经济因素的影响。要随着社会生产力和人民生活水平提高适时增加军人工资待遇,推进军官职业化进程,并完善国防生选拔培养制度。 相似文献
256.
An algorithm is given for the conditional p-center problem, namely, the optimal location of one or more additional facilities in a region with given demand points and one or more preexisting facilities. The solution dealt with here involves the minimax criterion and Euclidean distances in two-dimensional space. The method used is a generalization to the present conditional case of a relaxation method previously developed for the unconditional p-center problems. Interestingly, its worst-case complexity is identical to that of the unconditional version, and in practice, the conditional algorithm is more efficient. Some test problems with up to 200 demand points have been solved. © 1993 John Wiley & Sons, Inc. 相似文献
257.
进行了两类压剪加载实验:(1)利用石英的平面正碰撞产生压剪加载的实验,采用电磁质速法测试装药试件内部不同质点的运动情况,分析炸药装药中发生化学反应的可能性;(2)在压剪炮上采用平行倾斜碰撞产生压剪加载的实验,观测炸药装药爆炸的可能性。由实验可以看出:在亚爆轰状态的压缩加载应力条件下,剪切的联合作用对炸药的起爆起到敏化作用,适当比例的压剪加载造成更加敏感的炸药起爆响应。文中给出了起爆响应规律和响应机制的实验分析。 相似文献
258.
文中介绍了IRM-PC机上多功能仿真软件GASP/PC的开发,叙述了GASP/PC仿真语言的形成以及对于连续、离散和复合仿真模型的GASP/PC语言的结构与仿真方法。 相似文献
259.
提出只更新飞行剖面参数的航程更新方法及相应的RLV再入标准轨道制导规律;结合轨道在线生成与跟踪技术,采用Runge-Kutta-Fehlberg自适应变步长轨道快速预报方法,研究了RLV再入轨道预测制导。进一步对两种制导方法进行了比较分析研究,研究认为标准轨道制导与轨道预测制导都是可行的RLV再入制导方案,其有机结合是未来可重复使用跨大气层飞行器再入制导的发展趋势。 相似文献
260.
Reliability data obtained from life tests and degradation tests have been extensively used for purposes such as estimating product reliability and predicting warranty costs. When there is more than one candidate model, an important task is to discriminate between the models. In the literature, the model discrimination was often treated as a hypothesis test and a pairwise model discrimination procedure was carried out. Because the null distribution of the test statistic is unavailable in most cases, the large sample approximation and the bootstrap were frequently used to find the acceptance region of the test. Although these two methods are asymptotically accurate, their performance in terms of size and power is not satisfactory in small sample size. To enhance the small‐sample performance, we propose a new method to approximate the null distribution, which builds on the idea of generalized pivots. Conventionally, the generalized pivots were often used for interval estimation of a certain parameter or function of parameters in presence of nuisance parameters. In this study, we further extend the idea of generalized pivots to find the acceptance region of the model discrimination test. Through extensive simulations, we show that the proposed method performs better than the existing methods in discriminating between two lifetime distributions or two degradation models over a wide range of sample sizes. Two real examples are used to illustrate the proposed methods. 相似文献