基于量子行为烟花算法的移动机器人路径规划及平滑

针对移动机器人全局路径规划问题,提出一种基于量子行为烟花算法(quantum-behaved fireworks algorithm,QFWA)的路径规划方法.改进算法在基本烟花算法(fireworks algorithm, FWA)的基础上增加了基于量子行为的烟花爆炸策略.该策略使得种群在接近全局最优时具有较强的局部搜索能力,同时在种群远离全局最优位置时具有较强的全局搜索能力.改进算法提高了烟花爆炸产生火花的多样性和算法的收敛速度.在Benchmark测试函数上将改进算法与其他几种优化算法进行了对比,结果表明改进算法的性能优于其他算法.将QFWA应用于求解移动机器人路径规划问题,并采用均值滤波结合人工势场法对规划出的路径进行路径平滑处理.仿真实验结果表明改进方法在移动机器人路径规划问题上的可行性和有效性.     

成渝的发展路径特征及新时代的转型和区域发展策略

在面向新时代的征程中,成渝肩负 着探索并引领突破传统发展路径依赖、在 竞争与合作中实现转型与创新发展的重要 历史使命。本文以成都与重庆为比较研究对 象,分析成渝的发展路径特征。首先探究两 市1986—2016年间需求侧“三架马车”对经 济增长的贡献,然后引入供给侧多增长要素 解析城市经济增长的显著贡献要素及其贡献 度;进而结合改革开放以来的经济发展背景 及政策导向,辨析成渝两市发展路径特征与 变化趋势。最后基于比较研究,探讨面向新 时代的城市经济转型与区域协调发展之路。     

Time-optimal path generation for continuous and quasi-continuous path control of industrial robots

For a given continuous path, the problem of designing a time-optimal time-parametrization is considered. First, algorithms are presented which, under rather mild assumptions, yield the exact solution within two computational steps consisting of a forward and a backward computation. Then, the problem of quasi-continuous robot motion is investigated in detail. An algorithm of the same type results, but the computational burden is considerably reduced by making appropriate use of the special structure of the problem. By this, on-line use becomes feasible.Work supported by Oesterreichischer Fonds zur Foerderung der wissenschaftlichen Forschung.     

基督教堂建筑空间的发展与演绎

本文主要分析基督教堂随着基督教的发展而在历史进程中所出现的空间形式与最后所确定下来的空间模式,并以“中心”和“路径”为空间模式分析了基督教空间,以及现代基督教堂对此的演绎。     

A survey on coverage path planning for robotics

Coverage Path Planning (CPP) is the task of determining a path that passes over all points of an area or volume of interest while avoiding obstacles. This task is integral to many robotic applications, such as vacuum cleaning robots, painter robots, autonomous underwater vehicles creating image mosaics, demining robots, lawn mowers, automated harvesters, window cleaners and inspection of complex structures, just to name a few. A considerable body of research has addressed the CPP problem. However, no updated surveys on CPP reflecting recent advances in the field have been presented in the past ten years. In this paper, we present a review of the most successful CPP methods, focusing on the achievements made in the past decade. Furthermore, we discuss reported field applications of the described CPP methods. This work aims to become a starting point for researchers who are initiating their endeavors in CPP. Likewise, this work aims to present a comprehensive review of the recent breakthroughs in the field, providing links to the most interesting and successful works.     

基于改进遗传模拟退火算法的WSN路径优化算法*

为了更好地解决无线传感器网络（WSN）数据传输的路径优化问题,降低数据传输的能量消耗,提出了一种基于改进遗传模拟退火算法（SAGA）的WSN路径优化算法。首先根据优化目标建立数学模型,然后设计了种群的编码方式,并对遗传算法中的适应度函数、交叉算子、变异算子进行改进,使算法能够更加有效地避免陷入局部搜索;接着根据旧种群和新种群每个对应个体的不同进化程度提出了一种新的Metropolis准则,使模拟退火算法的跳变更具有规律性。实验结果显示：与其它路径优化算法相比,该算法不仅能生成更节能的数据传输路径,而且优化时间也大大降低。所以该算法是一种高效的路径优化算法。     

Cooperative schemes for path establishment in mobile ad-hoc networks under shadow-fading

The performance of routing protocols for multi-hop path-establishment in Mobile Ad-hoc NETworks (MANET) is examined when the individual radio links undergo shadow fading of parameterized severity. Such propagation modeling is typical of ground-level networking along with node mobility. The metrics of main interest are the probability of having a reliable multi-hop path plus the temporal statistics of such availability under a Markovian model. Such availability is an indicator for the suitability of the network to carry delay-sensitive applications (push-to-talk voice, streaming video) in uninterrupted manner. It is shown that high levels of diversity are necessary in such adverse environments, as obtained either by multiple independent paths or via concurrent cooperative transmission. Analytical and simulation comparisons of typical routing options are presented on the above metrics, plus on the required nodal engagement for supporting such diversity.     

Continuity and change in interorganizational project practices: The Dutch shipbuilding industry, 1950–2010

The Dutch shipbuilding industry has a longstanding tradition in project-based production. Recently, industry actors have acknowledged a serious misfit between interorganizational project practices, defined as behaviors related to collaboration, and interorganizational project demands, defined as environmental conditions. This misfit leads to a weaker competitive position due to higher communication and production costs, and longer production times. However, the causes of this misfit remain unclear. Among project researchers there is a growing awareness that history has a major influence on contemporary practices in interorganizational projects, suggesting that some of the causes of the present-day misfit may be rooted in the past. This paper studies historical developments of interorganizational project practices in Dutch shipbuilding projects, in order to understand to what extent contemporary misfit in project practices is rooted in the past and results from path dependencies and lock-ins. We answer the following research question: How did interorganizational project practices and demands in the Dutch shipbuilding industry develop between 1950 and 2010 and to what extent do these developments help us understand the current misfit between project practices and demands? Our results show that a web of self-reinforcing mechanisms at least partially explains the current misfit in the Dutch shipbuilding industry. This paper answers to the conceptual call by Sydow et al. (2009) and supplements path dependence literature by showing that self-reinforcing mechanisms causing path dependence can be separated analytically, but are intertwined empirically.     

粮食供应、人口增长与城镇化道路选择——谈小城镇在国家城镇化中的历史地位

本文从国际比较和历史的角度试图解释小城镇之所以成为一种＂中国特色＂的原因,并希望从新中国城市发展政策方针转变的背后,探寻其历史背景和深层次原因。文章提出在我国城镇化道路上的大城市与小城镇发展关系之争,其本质上反映出一个带着庞大的人口基数的农业社会向工业社会迅速转型的现实需求,体现的是国家现代化发展中工业与农业之间艰难的平衡关系。鼓励小城镇发展的政策曾经具有试图化解粮食供应危机、缓解工农紧张关系、促进农业现代化发展的现实理性,并且仍旧对我国未来的发展具有重要的战略意义。     

倾斜管实验的膏体流变特性规律研究

针对膏体流变特性难以真实测量的现象,自制一套能够有效还原工业现场的倾斜管道实验装置,对膏体流变特性参数进行测量,运用通径分析法探究膏体浓度、灰砂比对流变特性的影响规律。结果表明:膏体浓度、灰砂比对膏体流变参数的影响均为正相关,其中,浓度对屈服应力的影响水平比灰砂比对其影响水平大一个数量级,当灰砂比接近1∶25时,灰砂比的增大与减小并不能引起屈服应力明显的单调递增递减现象;浓度对塑性黏度的影响水平比灰砂比对其影响水平大,但在同一个数量级,膏体浓度较低时,会产生浓度低黏度大的现象。