面向负载均衡的高铁路网列车开行方案优化方法

针对当前高速铁路运营过程中存在的运输需求与运力资源不匹配现象,面向负载均衡原理研究了路网条件下运能可适配的高速铁路旅客列车开行方案优化与评估方法.首先,针对路网条件下列车开行方案优化,构建以提升经济效益、社会效益和网络负载均衡为目标的非线性混合整数规划模型,并设计基于遗传算法和粒子群算法的两阶段混合搜索求解算法.在此基础上,考虑开行列车在高速铁路网中的抗干扰能力,建立了面向网络化运营场景的开行方案综合评估指标体系,揭示了故障场景下高速铁路网络性能的演化规律.最后,以实际高速铁路线路数据和运营数据为场景进行仿真实验,本文提出方法在保证运输需求和路局收益的同时能够有效地提升8.66%网络整体负载均衡性,增强发生故障时网络的抗干扰能力.     

Proposal of variable sequential sampling plan having desired operating characteristics indexed by quality loss

The proportion of non-conforming items has been traditionally utilised as an evaluation criterion for quality of items. However, the proportion of non-conforming items is not necessarily useful as a proper evaluation criterion for controlling high-quality manufacturing in recent years. Accordingly, in order to achieve further quality improvement and innovation, more careful quality evaluation has been required newly. Then, a concept of quality loss in the Taguchi methods has been devised as a severe criterion of quality evaluation. Hereby, a variable single sampling plan having desired operating characteristics (OCs) indexed by quality loss has been proposed in the area of statistical quality control. By the way, the most economical sampling inspection in the average sample number (ASN) is the sequential sampling plan based on the Wald’s sequential probability ratio test. Then, from the viewpoint of cost reduction, we discuss a variable sequential sampling plan having desired OC indexed by quality loss with the aim of expansion of the utility of variable sampling plan for quality loss. As the result, the design procedure of the sequential sampling plan for satisfying some required design conditions indexed by quality loss is provided. In addition, the effectiveness of the proposed sequential sampling plan is verified through some numerical examples.     

A Single Sampling Plan Based on Exponentially Weighted Moving Average Model for Linear Profiles

The exponentially weighted moving average (EWMA) model has been successfully used in acceptance sampling plans. The EWMA model provides the quality information of the current lot and the preceding lots. In addition, a multiple dependent state (MDS) sampling plan considers the quality information of the preceding lots. In this study, we present two new sampling plans for linear profiles. One is based on EWMA model with yield index using the single sampling plan, and the other is based on EWMA model with yield index using the MDS sampling plans. The plan parameters are determined by a nonlinear optimization approach. As the smoothing parameter value equals to one, the first proposed plan becomes the traditional single sampling plan. In addition, we compare the proposed plans with the traditional single sampling plan. The results indicate that the MDS sampling plan based on EWMA model with yield index with smaller value of smoothing parameter performs better than the traditional single sampling plan and the single sampling plan based on EWMA model with yield index in terms of the sample size required. One real example is used to illustrate the proposed plan. Copyright © 2015 John Wiley & Sons, Ltd.     

CATIA V5环境下基于产品数模的三坐标测量机测点自动采样

为了实现CAD与CAIP(计算机辅助测量规划)的集成,提出了一种基于产品三维模型的CMM(三坐标测量机)测量点采样方法。该方法从产品的IGES文件中有效识别型面形状与边界定义,采用均匀采样与依曲率变化二次采样相结合的策略,针对各个型面类型制定专门的信息处理机制,实现测量点的自动采样,并通过转换在参数平面中判断采样点与裁剪区域的隶属关系,以有效剔除无效采样点;通过典型飞机部件外形曲面的采样点生成结果表明,该方法能有效应用于飞机的测量规划中。     

智能科学与技术本科专业“小学期”制教学思考

针对湖南大学智能科学与技术专业现行本科教学计划专业特色、学科交叉性等问题,在分析新的小学期制度基础上,本文阐述新制订的智能科学与技术专业本科教学计划,并探索了小学期制度下教学改革的部分举措,以期通过调整和改革使湖南大学智能科学与技术本科专业的建设更上一个台阶,为本专业的人才培养作出积极贡献。     

基于改进遗传算法的TD-SCDMA扇区优化

获得满意的覆盖是TD-SCDMA标准网络规划的重点,为此,在遗传算法的基础上提出基于PCCPCH RSCP覆盖和PCCPCH C/I覆盖的改进遗传算法。采用符合网络多扇区多参数性质的二进制矩阵式编码,为加快收敛速度,给出基于块的交叉方法,同时为防止过早的局部收敛,对适应度函数进行尺度变换。实验结果表明,该算法可以快速收敛到目标解,PCCPCH RSCP覆盖比例和PCCPCH C/I覆盖比例均有不同程度的提升。     

基于蚁群优化算法的旋转货架拣选路径规划

给出自动化立体仓库单拣选台分层水平旋转货架系统的数学模型,提出一种改进的蚁群优化算法,用于解决货物拣选路径规划问题。该算法能快速找到最优货物拣选路径,得到的解质量较高且计算时间短。仿真结果表明,该方法适用于求解中小规模货物拣选路径的规划问题,可以提高自动存储作业效率。     

Integration of product design,process planning,scheduling, and FMS control using XML data representation

An efficient model for communications between CAD, CAPP, and CAM applications in distributed manufacturing planning environment has been seen as key ingredient for CIM. Integration of design model with process and scheduling information in real-time is necessary in order to increase product quality, reduce the cost, and shorten the product manufacturing cycle. This paper describes an approach to integrate key product realization activities using neutral data representation. The representation is based on established standards for product data exchange and serves as a prototype implementation of these standards. The product and process models are based on object-oriented representation of geometry, features, and resulting manufacturing processes. Relationships between objects are explicitly represented in the model (for example, feature precedence relations, process sequences, etc.). The product model is developed using XML-based representation for product data required for process planning and the process model also uses XML representation of data required for scheduling and FMS control. The procedures for writing and parsing XML representations have been developed in object-oriented approach, in such a way that each object from object-oriented model is responsible for storing its own data into XML format. Similar approach is adopted for reading and parsing of the XML model. Parsing is performed by a stack of XML handlers, each corresponding to a particular object in XML hierarchical model. This approach allows for very flexible representation, in such a way that only a portion of the model (for example, only feature data, or only the part of process plan for a single machine) may be stored and successfully parsed into another application. This is very useful approach for direct distributed applications, in which data are passed in the form of XML streams to allow real-time on-line communication. The feasibility of the proposed model is verified in a couple of scenarios for distributed manufacturing planning that involves feature mapping from CAD file, process selection for several part designs integrated with scheduling and simulation of the FMS model using alternative routings.     

PowerPoint“控件工具箱”典型应用三例

PowerPoint是教师制做课件最常用的软件之一,该软件的控件工具箱功能十分强大。该文列举出控件工具箱在制做课件时的三个典型应用,分别是嵌入FLASH动画,导入视频文件,插入滚动文本。     

网络工程实用人才培养

为满足网络工程专业人才培养需求,我校对网络工程实用人才的培养进行一系列改革。紧扣院校培养高级应用型人才的主旨,在专业定位、培养目标、培养模式、课程体系、教材建设、实验室建设等方面作了大量研究,提出符合学校实际的培养方案。实践证明,该方案的实施增强了学生的动手实践能力,提高了就业率。