点集局部处处为凸的外包线自动生成

在海岸工程的数学模型中,原始地形数据一般表现为一系列平面点的坐标,而在数学建模过程中往往需要根据该点集(坐标)人工给定模拟区域的边界。可根据事先设定的搜索点数得到点集的外包线,不同的搜索点数可以得到不同的外包线。一般说来,随着搜索点数的增加,外包线内的面积也不断增大,直到得到该区域的凸包(该凸包一般不是所要寻找的)。外包线内的面积与凸包的面积比值,定义为该外包线的凸度。为了减少手工工作的劳动量,提出了一个根据给定点集,自动寻找其合适外包线的算法。同时给出了外包线的调整算法,使得寻找到的外包线更加贴近初始给定的情形。最后应用该程序对渤海区域边界点数据进行了边界寻找,效果良好。     

变精度粗糙集模型在空袭兵器类型识别中的应用

针对经典粗糙集模型解决空袭兵器类型识别问题时的不足,文章提出了一种改进的相似度,建立了基于改进相似度的变精度粗糙集模型并提出了基于重要度的属性约简算法。最后利用一组测试样本对模型进行了检验,结果表明模型准确、可靠。     

基于粗糙集的船舶主机轴系故障诊断

船舶主机轴系的故障诊断对船舶正常航运具有重要意义.将粗糙集理论应用到船舶主机轴系故障诊断中,建立了基于粗糙集的船舶主机轴系故障诊断模型.采用NaiveScaler方法对故障数据离散化处理,利用基于属性重要度的启发式算法进行属性约简,获取故障诊断相关规则.算例验证了该模型的有效性.     

浅谈数字化时代下的家庭数字电视

广播电视已进入数字化时代,对数字电视应有新的认识。介绍了数字电视的概念和优势。着重介绍了数字电视机顶盒分类,数字化下的家庭有线电视的布线要求和数字电视机顶盒的简单安装。对人们认识数字化时代下的家庭数字电视有一定启迪。     

电子调速器在发电机组并联中的应用

介绍了电子调速器的技术性能指标、各种功能及在发电机组单机运行和并联时使用调试方法及注意事项。     

Exploring public transport sustainability with neutrosophic logic

Sustainable transportation is a significant component of overall sustainable development. Increasingly, evaluation and decision-making with respect to major complex projects (for example, transportation and land use projects), a multiple attribute perspective is taken. This paper illustrates a multiple attribute decision-making approach for selecting sustainable public transportation systems under uncertainty, that is, with partial or incomplete information represented by single-valued neutrosophic sets (SVNSs). A SVNS is a generalization of a classical set, a fuzzy set, and an intuitionistic fuzzy set. Here, SVNSs and SVNS connectives are illustrated in the context of a ‘Public Transit Sustainable Mobility Analysis Tool’ (PTSMAT) which involves a composite (multiple attribute) sustainability index. A case study of PTSMAT is provided for the UBC Corridor study in Vancouver, Canada. As expected, similar results are obtained to the original study, though the neutrosophic formalism opens a wide range of possibilities for recognition of uncertainty in sustainability assessment.     

Network sensor health problem

Many existing studies on the sensor health problem determine an individual sensor’s health status based on the statistical characteristics of collected data by the sensor. In this research, we study the sensor health problem at the network level, which is referred to as the network sensor health problem. First, based on the conservation principle of daily flows in a network, we separate all links into base links and non-base links, such that the flows on the latter can be calculated from those on the former. In reality, the network flow conservation principle can be violated due to the existence of unhealthy sensors. Then we define the least inconsistent base set of links as those that minimize the sum of squares of the differences between observed and calculated flows on non-base links. But such least inconsistent base sets may not be unique in a general road network. Finally we define the health index of an individual sensor as the frequency that it appears in all of the least inconsistent base sets. Intuitively, a lower health index suggests that the corresponding sensor is more likely to be unhealthy. We present the brute force method to find all least inconsistent base sets and calculate the health indices. We also propose a greedy search algorithm to calculate the approximate health indices more efficiently. We solve the network sensor health problem for a real-world example with 16 nodes and 30 links, among which 18 links are monitored with loop detectors. Using daily traffic count data from the Caltrans Performance Measurement System (PeMS) database, we use both the brute-force and greedy search methods to calculate the health indices for all the sensors. We find that all the four sensors flagged as unhealthy (high value) by PeMS have the lowest health indices. This confirms that a sensor with a lower health index is more likely to be unhealthy. Therefore, we can use such health indices to determine the relative reliability of different sensors’ data and prioritize the maintenance of sensors.     

城市公共交通便捷性评价模型研究

科学地评价公共交通系统的便捷性,对方便居民公交出行的科学评价具有极为重要的现实意义.为评价城市公共交通的便捷程度,选取了公交站点覆盖率、公交线网密度等8个方便性评价指标和平均运送速度、乘客平均出行时耗等6个快捷性评价指标,构建了城市公共交通便捷性评价指标体系.引入Vague物元评价方法构建了城市公共交通评价模型,选取了2013年重庆主城区公共交通便捷性的主要指标对其进行了评价应用.评价结果表明:基于Vague理想解的城市公共交通便捷性评价模型能够科学评价城市公共交通系统的便捷性.     

低地板独立旋转车轮动力转向架设计

介绍了独立旋转车轮转向架在城市轨道交通中实现低地板的优势,提出了一种低地板独立旋转车轮动力转向架的设计方案.并利用有限元软件ANSYS根据UIC 615—4对转向架构架进行静强度分析.     

基于多目标优化遗传算法的武器-目标分配

针对武器‐目标火力分配问题,建立了基于效能最大和用弹量最少的多目标优化模型。基于 Pareto集非劣分层思想对遗传算法进行改进,利用非劣分层遗传算法处理武器‐目标分配多目标优化问题。非劣分层遗传算法通过对种群内的所有个体的多个目标函数进行非劣分层排序来度量个体的适应能力,通过遗传算法实现多样性进化操作,能够获取Pareto最优解集,以供决策者参考。仿真试验表明：该方法能够获得满意的分配结果,方便快捷地解决多平台多类型武器‐目标分配问题。