基于ZigBee网络和超声定位的智能跟随小车

基于成熟的IEEE802.15.4协议和ZigBee无线模块,结合超声定位,设计了一种新颖的智能跟随系统。设计的核心为PIC18F4620单片机和MRF24J40MA无线收发模块,通过无线收发来完成节点间的识别与同步,同时以超声测距系统完成对被跟踪目标的定位,通过控制驱动电机动作实现对指定目标的定距离跟随。控制网络以子网的形式控制不同系统的分时定位跟随,同时管理各移动定位系统的入网和切换。样机测试结果表明系统达到了预期的跟随设计要求,具有一定的工程使用价值。     

Two local search approaches for solving real-life car sequencing problems

The NP-hard problem of car sequencing appears as the heart of the logistic process of many car manufacturers. The subject of the ROADEF’2005 challenge addressed a car sequencing problem proposed by the car manufacturer RENAULT, more complex than the academic problem generally addressed in the literature. This paper describes two local search approaches for this problem. In the first part, a new approach by very large-scale neighborhood search is presented. This approach, designed during the qualification stage preceding the final, is based on an original integer linear programming formulation. The second part is dedicated to the approach which enabled us to win the ROADEF’2005 challenge. Inspired by the latest works on the subject, this one is based on very fast explorations of small neighborhoods. Our contribution here is mainly algorithmic, in particular by showing how much exploiting invariants speeds up the neighborhood evaluation and contributes to the diversification of the search. Finally, the two approaches are compared and discussed through an extensive computational study on RENAULT’s benchmarks. The main conclusion drawn at this point is that sophisticated metaheuristics are useless to solve car sequencing problems. More generally, our victory on ROADEF’2005 challenge demonstrates that algorithmic aspects, sometimes neglected, remain the key ingredients for designing and engineering high-performance local search heuristics.     

Intercept-resend attacks on Chen et al.'s quantum private comparison protocol and the improvements

Recently, Chen et al. presented a novel quantum private comparison (QPC) protocol using triplet GHZ state to enable two parties to compare the equality of their information without revealing the content. The protocol is rather promising because it only requires single-photon measurement with the help of a semi-honest third party to complete the secret comparison. However, this study will point out that a weakness could occur in the eavesdropping check phase. That is, an intercept-resend attack could be launched by one of the two participants to reveal the information content of the other participant—a result that contradicts to the security requirement of a QPC. Fortunately, two solutions are possible to avoid the attack.     

基于灰色聚类分析的风险评价方法研究——以江苏民间资本进入金融领域风险评价为例

运用灰色系统理论,结合AHP方法,建立灰色聚类分析模型,对风险进行评价,并以江苏民间资本进入金融领域风险评价为例进行研究.结果表明,民间资本进入金融领域的风险属于高风险范畴,其中进入风险中的产业风险和社会风险属于高风险,信用风险属于较高风险,政治风险属于中等风险.并针对上述风险的等级,提出了相应的政策建议.模型具有一定的实用价值,它对于正确认识民间资本进入金融领域的风险和有针对性地制定相应的政策措施具有一定的理论和现实意义.     

110警车配置及巡逻方案

针对110警车调度问题,引入了图论中的最短路算法以及计算几何的相关理论,建立了车辆调配模型、巡逻路线模型以及基于模糊数学的评价指标模型.另外,用C++编写了一个可视化的软件,不仅实现了手动描点,自动求出覆盖线段集合的功能,同时利用计算机模拟警车的巡逻路线,最后通过计算机检验得到结果,其合理性和实用性都令人满意.针对问题一,通过人机结合,配置17辆警车就能实现D1的目标,很好地兼顾了警车巡逻的运行成本,减少公安部门车辆和人员等的投入.针对问题二,采用模糊数学相关理论使评价指标实现了从定性到定量的转变.针对问题三和六,在D1的基础上,兼顾了巡逻效果的显著性,采用最少被巡逻道路优先的贪心算法建立了动态巡逻模型,得到了合理的巡逻方案.在此方案中,我们动用了30辆警车完成了问题一的目标.另外还额外考虑了案发事件概率不均匀分布的情况,建立了改进模型.针对问题四,在完成问题三指标的基础上,为了尽可能提高巡逻车辆的隐蔽性和增强巡逻效果,采用轮盘赌算法来引入随机性.针对问题五,采用最远距离道路优先贪心策略,使模型尽可能满足条件D1,D2.针对问题七,提出了一些额外因素及其解决方案,进一步完善了模型,使模型更贴近现实.     

EFFECT OF FORESTLAND AVAILABILITY BY OWNERSHIP TYPE ON LICENSE SALES FOR HUNTING: A SPATIAL APPROACH

Abstract The effect of forestland availability under different ownership types on license sales for hunting in nine Southeastern states is empirically evaluated. An equation that represents license sales for hunting is estimated assuming the sale of hunting licenses in a particular county is related to the characteristics of that county as well as the characteristics and license sales for hunting in its neighboring counties. The positive effects of the amounts of both national and private forestland on license sales reaffirm the potential benefits of maintaining forestland to stimulate hunting. The positive spillover effect of national forests on license sales for hunting suggests that availability and close access to hunting in national forests within neighboring counties are important in supporting hunting license sales in a county. This study contributes to the general understanding of the drivers affecting individuals’ decisions to use natural resources for hunting. Advances in natural resource modeling, specifically the spatial process model and geospatial data used in this research, make it possible to examine the interactions between the spatial dynamics and ownership attributes of the natural system, allowing policy makers to design natural resource management practices that respond to a system characterized by these interactions.     

信贷风险决策问题的一种相互逼近算法

基于最速下降法的基本思想 ,提出了相互逼近算法 ,用以解决信贷风险决策过程中 ,利润曲线和风险曲线寻求公共最优近似解的问题 .该算法表明 ,当利润曲线和风险曲线不存在公共最优近似解时 ,银行追求利润最大化的结果将导致风险上升 ,无法在可接受的风险指数范围内实现其既定的盈利目标 .但当利润曲线和风险曲线存在公共最优近似解时 ,银行根据其所掌握的私有信息以及所观测到企业理性的反应 ,作出相应的决策 .公共最优近似解的存在 ,说明了银行是在风险可接受的前提下按最优性原则给企业发放贷款 .     

机构投资者增持的经济后果:基于定向增发的实证研究

定向增发背景下,对机构投资者增持行为经济后果展开研究具有重要的现实意义。以2008-2017年我国沪深A股成功进行定向增发的上市公司为样本,本研究采用OLS、POISSON、PSM等方法对机构投资者增持的经济后果及机理进行实证分析与稳健性检验。结果表明:机构投资者整体增持与定向增发上市公司的长期市场表现正相关。考虑机构投资者异质性特征并做进一步分析,价值投资型机构投资者增持行为通过提升企业创新水平显著提升了定向增发上市公司长期市场表现;由于追求短期股权价值波动收益,价格追随型机构投资者增持行为则不利于定向增发上市公司长期市场表现;限售期规定能够有效遏制价格追随型机构投资者的“追涨杀跌”行为。本研究为我国中长期价值投资型机构投资者培育、定向增发资源配置效率提升提供了理论依据。