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1.
基于区间数的DS证据合成方法研究   总被引:1,自引:0,他引:1  
在DS证据理论的应用过程中,命题的基本概率赋值函数起到了关键的作用,传统DS证据理论中基本概率赋值函数的取值为[0,1]中的单点值.在很难准确将证据所支持命题的基本概率赋值表示为[0,1]之间的单点值时,可以用区间数形式来表示命题的基本概率赋值.在建立符合运算封闭性的区间数广义求和与广义乘积算子的基础上,定义了基于区间数的基本概率赋值函数、信任函数以及似然函数等重要概念,给出了证据合成规则,进而提出了基于区间数的DS证据合成方法.计算实例表明,与传统DS证据合成方法相比,基于区间数的DS证据合成方法具有更灵活的应用特性和更小的计算复杂度.  相似文献   

2.
基于水雷气动不平衡式发射内弹道数学模型,建立了轴向受力和出管速度的泛函表达式,以基本可行解为基准,对可行解区间进行了仿真计算,通过将轴向受力和出管速度函数在基本可行解处一阶泰勒展开,并采用分段函数表示可行解各分量的变化律,从而将非线性问题转化为线性规划问题,运用单纯形法进行优化求解,得到了最优发射条件.  相似文献   

3.
线性插值法   总被引:1,自引:0,他引:1  
在数值计算上,经常用逐段外切、内接或最优逼近直线来近似函数,以插值代替函数值的计算。本文根据电子数字计算机的特点,对用折线近似函数的插值方法加以改进,达到简化计算的目的。 [例1]在气象站经常要计算所测高度上的表定值。今用逐段直线来近似气压随高度的对应律,取步长为500米,逼近区间为0~5000米,各分点处的高度及其对应的气压值如下表:  相似文献   

4.
针对复杂防空作战环境下多目标优先级难以准确评估的问题,提出了基于区间直觉模糊集理论的目标优先级求解算法。首先系统分析了影响目标优先级的因素以及各影响因素与目标优先级之间的非线性关系。其次,对区间直觉模糊集的得分函数和精确函数进行了改进,考虑了犹豫度信息对决策结果的影响,并且提出了基于得分函数和精确函数的目标优先级求解算法。最后通过仿真算例验证了算法的有效性。  相似文献   

5.
基于动态子结构方法,将结构中的弹性连接单独划分成一个独立子结构,并利用零质量空间梁单元对其进行等效,分别基于频域子结构方法(FRF-based Substructuring Method)和模态综合法(Component Mode Synthesis)对考虑弹性连接的结构固有频率和频响函数进行了推导.基于此,将空间梁单元的弹性模量和比例阻尼系数设成区间参数以模拟弹性连接的区间不确定性,基于区间因子法(Interval Factor Method,IFM)分别给出了考虑区间弹性连接结构固有频率和频响函数的区间上下限,从而形成了两种计算分析方法,即CMS-IFM和FBSM-IFM.通过仿真将两种方法与Monte-Carlo模拟方法的计算结果进行了对比,结果表明:CMS-IFM和FBSM-IFM正确高效.  相似文献   

6.
§1 引言在生产和科学实验中常常遇到以下情况:仅能测出某函数的一系列的离散点处的函数值,但却要根据这一系列值求出函数在其他各点处的值。还有另一种情况:某连续函数在理论上的表示虽然是已知的,但根据这种表示式只能计算一些特殊点处的函数值,而函数在其他各点处的值要利用公式计算却十分复杂和困难。这些情况都需要利用函数  相似文献   

7.
本文推证了一个积分展开定理。根据这个定理,一个闭区间上定义的具有展成泰勒级数条件的函数,可以在一个特定的基函数上展开,而其展式的系数总含有这个函数在该区间上的多重积分。然后给出一个将该定理应用于制导的例子。  相似文献   

8.
将信任函数理论应用到了仿真结果评估问题中,给出了总体仿真结果的信任函数和信念区间的计算方法。对仿真结果的真实性评估具有一定意义。这种思想和算法可推广应用到其它各种不确定性推理决策问题中去。  相似文献   

9.
针对单列车节能运行问题,提出了一种基于时间离散化的单列车节能运行优化模型。首先将列车运行时间离散为足够小的等间隔子区间,建立时间子区间内列车速度的表达式,通过比较各子区间端点的速度大小,确定子区间内列车的运行工况,进而推导出牵引总耗能;然后以牵引总耗能最小为目标函数,建立单列车节能运行优化模型;最后将模型应用于实际算例,得到其最节能运行的速度距离曲线。  相似文献   

10.
服从正态分布律的随机变量落在给定区间内的概率,通常用拉普拉斯函数随机变量X落在区间(α,β)内的概率来表示,即式中σ-均方差;m-数学期望。利用变数变换:令则(1)式变为:从(2)式中看出,e~(-t)~2的原函数不是初等函数,因此(2)式不能按定义直接求出。为了要求出概率P(α相似文献   

11.
An availability measure is the probability that a two-state system modeled by an alternating renewal process is available at one or more points or intervals. The concept of availability measures is extended to formulae for the joint prediction of availability and numbers of breakdowns (or repairs) of the system during a fixed interval.  相似文献   

12.
This paper applies the well-known reflection principle for random walks to the analysis of the transient M/M/1 queueing system. A closed-form solution is obtained for the probability that exactly i arrivals and j departures occur over an interval of length t in an M/M/1 queueing system that contains n users at the beginning of the interval. The derivation of this probability is based on the calculation of the number of paths between two points in a two-dimensional −y coordinate system that lie above the x axis and touch the x axis exactly r times. This calculation is readily performed through the application of the reflection principle.  相似文献   

13.
A policy of periodic replacement with minimal repair at failure is considered for a complex system. Under such a policy the system is replaced at multiples of some period T while minimal repair is performed at any intervening system failures. The cost of a minimal repair to the system is assumed to be a nonde-creasing function of its age. A simple expression is derived for the expected minimal repair cost in an interval in terms of the cost function and the failure rate of the system. Necessary and sufficient conditions for the existence of an optimal replacement interval are exhibited in the case where the system life distribution is strictly increasing failure rate (IFR).  相似文献   

14.
The following zero-sum game is considered. Red chooses in integer interval [1, n] two integer intervals consisting of k and m points where k + m < n, and Blue chooses an integer point in [1, n]. The payoff to Red equals 1 if the point chosen by Blue is at least in one of the intervals chosen by Red, and 0 otherwise. This work complements the results obtained by Ruckle, Baston and Bostock, and Lee. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44: 353–364, 1997  相似文献   

15.
Instead of measuring a Wiener degradation or performance process at predetermined time points to track degradation or performance of a product for estimating its lifetime, we propose to obtain the first‐passage times of the process over certain nonfailure thresholds. Based on only these intermediate data, we obtain the uniformly minimum variance unbiased estimator and uniformly most accurate confidence interval for the mean lifetime. For estimating the lifetime distribution function, we propose a modified maximum likelihood estimator and a new estimator and prove that, by increasing the sample size of the intermediate data, these estimators and the above‐mentioned estimator of the mean lifetime can achieve the same levels of accuracy as the estimators assuming one has failure times. Thus, our method of using only intermediate data is useful for highly reliable products when their failure times are difficult to obtain. Furthermore, we show that the proposed new estimator of the lifetime distribution function is more accurate than the standard and modified maximum likelihood estimators. We also obtain approximate confidence intervals for the lifetime distribution function and its percentiles. Finally, we use light‐emitting diodes as an example to illustrate our method and demonstrate how to validate the Wiener assumption during the testing. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008  相似文献   

16.
This article deals with a two‐person zero‐sum game in which player I chooses in integer interval [1, N] two integer intervals consisting of p and q points where p + q < N, and player II chooses an integer point in [1, N]. The payoff to player I equals 1 if the point chosen by player II is at least in one of the intervals chosen by player II and 0 otherwise. This paper complements the results obtained by Ruckle, Baston and Bostock, Lee, Garnaev, and Zoroa, Zoroa and Fernández‐Sáez. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 98–106, 2001  相似文献   

17.
Aiming at the problems of demagnetization effect of electromagnetic buffer (EMB) caused by high ve-locity under intensive impact load and the difficulty and error of machining composite thin-walled long tube, a segmented EMB is proposed. The inner tube and air-gap are divided into initial segments and the traversing segments. Through theoretical analysis, impact test and simulation, it can be found that the RRF curve has two peaks. Firstly, in order to reduce the resultant resistance force (RRF) peaks, the sensitivity analysis based on optimal Latin hypercube design (OLHD) and polynomial regression was performed. The results show that the smallest contribution ratio to the dynamic response is the seventh and ninth segments of the inner tube, which are less than 1%. Then, fully considering the uncertain factors, important parameters are selected for uncertain optimization after sensitivity analysis. The in-terval order and interval probability degree methods are used to establish interval uncertain optimiza-tion model of the RRF considering robustness. The model was solved using an interval nested optimization method based on radial basis function (RBF) neural network. Finally, the Pareto front is obtained and numerical simulation is performed to verify the optimal value. It indicates that the two kinds of RRF peak is obviously reduced, and the optimization object and strategy are effective.  相似文献   

18.
This article concerns the location of a facility among n points where the points are serviced by “tours” taken from the facility. Tours include m points at a time and each group of m points may become active (may need a tour) with some known probability. Distances are assumed to be rectilinear. For m ≤ 3, it is proved that the objective function is separable in each dimension and an exact solution method is given that involves finding the median of numbers appropriately generated from the problem data. It is shown that the objective function becomes multimodal when some tours pass through four or more points. A bounded heuristic procedure is suggested for this latter case. This heuristic involves solving an auxiliary three-point tour location problem.  相似文献   

19.
A cutting plane scheme embedded in an implicit enumeration framework is proposed for ranking the extreme points of linear assignment problems. This method is capable of ranking any desired number of extreme points at each possible objective function value. The technique overcomes storage difficulties by being able to perform the ranking at any particular objective function value independently of other objective values. Computational experience on some test problems is provided.  相似文献   

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