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61.
62.
基于神经网络的模糊理论在桥梁状态评估中的应用 总被引:1,自引:0,他引:1
探讨了模糊数学中的隶属函数在桥梁技术等级状态评估中的应用.在研究现有桥梁状态评估方法的基础上,把人工神经网络和模糊数学理论结合起来应用于大跨度预应力斜拉桥的等级状态评估,建立了基于三层神经元的模糊神经网络模型,并建立结构损伤度函数及等级隶属度模型,通过样本学习训练,获取评估专家的知识及直觉思维,最终确定桥梁所对应的技术状态等级.以检测的480组索力数据作为学习样本,另外4组作为验证样本进行了索力状态评估预测.计算结果表明,网络预测值与期望值吻合良好. 相似文献
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针对复杂钢坯加热过程,提出了一种免疫克隆进化模糊神经网络(ICE-FNN)控制算法。首先根据现场样本数据建立过程神经网络模型;然后基于该模型,采用模糊神经网络控制器(FNNC)规则优化算法,确定FNNC的最佳规则数;最后由FNNC的规则优化所得参数构造初始种群的一个解,采用免疫克隆进化(ICE)算法对FNNC参数优化。该算法具有全局寻优和局部求精能力,仿真结果证实了其有效性。 相似文献
66.
研究了一类具有拟周期外力的非自治发展方程,通过延伸相平面将非自治系统转化为自治系统,再证明相应的自治系统的时滞惯性流形的存在性,并在时滞惯性流形的基础上构造了非自治发展方程的近似惯性流形。 相似文献
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卫星任务规划与调度是空间资源管理的重要内容之一,其目的在于为卫星系统的任务计划编制提供科学合理的决策手段与依据。卫星任务调度问题的重要特点在于,调度任务存在可见时间窗口约束。只有在可见时间窗口内,调度任务才可能执行并完成。在进行合理假设的基础上,建立卫星任务调度问题的约束规划模型。对基本禁忌搜索算法进行改进,提出了模型求解的变邻域禁忌搜索算法。应用结果表明,约束规划模型的建立与求解是合理的。 相似文献
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《防务技术》2020,16(5):1073-1087
Because of the uncertainty and subjectivity of decision makers in the complex decision-making environment, the evaluation information of alternatives given by decision makers is often fuzzy and uncertain. As a generalization of intuitionistic fuzzy set (IFSs) and Pythagoras fuzzy set (PFSs), q-rung orthopair fuzzy set (q-ROFS) is more suitable for expressing fuzzy and uncertain information. But, in actual multiple attribute decision making (MADM) problems, the weights of DMs and attributes are always completely unknown or partly known, to date, the maximizing deviation method is a good tool to deal with such issues. Thus, combine the q-ROFS and conventional maximizing deviation method, we will study the maximizing deviation method under q-ROFSs and q-RIVOFSs in this paper. Firstly, we briefly introduce the basic concept of q-rung orthopair fuzzy sets (q-ROFSs) and q-rung interval-valued orthopair fuzzy sets (q-RIVOFSs). Then, combine the maximizing deviation method with q-rung orthopair fuzzy information, we establish two new decision making models. On this basis, the proposed models are applied to MADM problems with q-rung orthopair fuzzy information. Compared with existing methods, the effectiveness and superiority of the new model are analyzed. This method can effectively solve the MADM problem whose decision information is represented by q-rung orthopair fuzzy numbers (q-ROFNs) and whose attributes are incomplete. 相似文献
69.
《防务技术》2020,16(1):201-207
Three different kinds of PELE (the penetrator with lateral efficiency) were launched by ballistic artillery to impact the multi-layer spaced metal target plates. The impact velocities of the projectiles were measured by the velocity measuring system. The damage degree and process of each layer of target plate impacted by the three kinds of projectiles were analyzed. The experimental results show that all the three kinds of projectiles have the effect of expanding holes on the multi-layer spaced metal target plates. For the normal structure PELE(without layered) with tungsten alloy jacket and the radial layered PELE with tungsten alloy jacket, the diameters of holes on the second layer of plates are 3.36 times and 3.76 times of the diameter of the projectile, respectively. For radial layered PELE with W/Zr-based amorphous composite jacket, due to the large number of tungsten wires dispersed after the impact, the diameter of the holes on the four-layer spaced plates can reach 2.4 times, 3.04 times, 5.36 times and 2.68 times of the diameter of the projectile. Besides, the normal structure PELE with tungsten alloy jacket and the radial layered PELE whit tungsten alloy jacket formed a large number of fragments impact marks on the third target plate. Although the number of fragments penetrating the third target plate is not as large as that of the normal structure PELE, the area of dispersion of fragments impact craters on the third target plate is larger by the radial layered PELE. The radial layered PELE with W/Zr-based amorphous composite jacket released a lot of heat energy due to the impact of the matrix material, and formed a large area of ablation marks on the last three target plates. 相似文献
70.
In this paper, a condition-based maintenance model for a multi-unit production system is proposed and analyzed using Markov renewal theory. The units of the system are subject to gradual deterioration, and the gradual deterioration process of each unit is described by a three-state continuous time homogeneous Markov chain with two working states and a failure state. The production rate of the system is influenced by the deterioration process and the demand is constant. The states of the units are observable through regular inspections and the decision to perform maintenance depends on the number of units in each state. The objective is to obtain the steady-state characteristics and the formula for the long-run average cost for the controlled system. The optimal policy is obtained using a dynamic programming algorithm. The result is validated using a semi-Markov decision process formulation and the policy iteration algorithm. Moreover, an analytical expression is obtained for the calculation of the mean time to initiate maintenance using the first passage time theory. 相似文献