密集观测场景下的敏捷成像卫星任务规划方法

针对密集观测场景下敏捷成像卫星任务规划问题求解空间大、输入任务序列较长的特点,综合考虑时间窗口约束、任务转移时卫星姿态调整时间、存储约束和电量约束,对敏捷成像卫星任务规划问题进行建模. 提出融合IndRNN和Pointer Networks的算法模型（Ind-PN）对敏捷成像卫星任务规划问题进行求解,使用多层的IndRNN结构作为算法模型的解码器. 基于Pointer Networks机制对输入任务序列进行选择,使用Mask向量考虑敏捷成像卫星任务规划问题中的各类约束. 基于Actor Critic强化学习算法对算法模型进行训练,以获得最大的观测收益率. 实验结果表明,对于密集观测场景下的任务规划,Ind-PN算法的收敛速度更快,可以获得更高的观测收益率.     

Pathways to eliminate carbon emissions via renewable energy investments at higher education institutions

Higher education institutions are among the many public and private sector entities that have committed to long-term sustainability goals in response to the threat of climate change. A key challenge for these institutions is establishing a commitment to make targeted investments in renewable energy technologies in support of emissions reduction goals. Such strategies require a vision to simultaneously coordinate strategic investments in renewable energy technologies with tactical operational decisions to achieve the desired benefits. In this paper, we formulate and solve a least-cost renewable energy capacity investment planning model to determine pathways to achieve emissions reduction strategies. Specifically, we apply our model to Rutgers University to evaluate its target of 100 % carbon neutrality. Using these insights, we share recommendations on how these strategies can be executed. This research serves as a springboard for administrators to assess and deploy their emissions reduction strategies, while ensuring system and financial constraints are satisfied.     

一种限制搜索区域的多比例尺最优路径规划算法*

针对现有大区域范围路径规划算法存在的一些问题,提出一种限制搜索区域的多比例尺最优路径规划算法。该算法在进行路径规划时,一方面根据路网的多比例尺信息对路网进行分级,另一方面对搜索区域进行合理限制。测试实验表明此算法可以提高路径规划的效率。     

基于操纵平稳性的液压挖掘机轨迹规划方法

以既能达到良好的轨迹规划精度,又有优良的操纵平稳性为目标,提出了一种挖掘机器人的智能轨迹规划方法.以挖掘姿态角为优化变量;油缸进程和加速度梯度为双目标;位置盲角和最佳切削范围为约束建立优化数学模型,采用遗传算法寻找最优值.对3种规划策略：被动修正法、主动调整法和智能规划法进行了行程和速度梯度对比,结果表明,采用优化规划方法可以大幅减少液压系统冲击和振动,使挖掘机操纵更加平稳.     

基于并行工程和网络计划技术的模具生产进度编制方法

在充分考虑模具生产的特点和生产活动之间并行性的基础上,建立了单副模具典型生产过程的细化网络图,提出了一种基于并行工程、网络计划技术和最优化生产技术(OPT,Optimal ProductionTechnology)的模具生产进度计划编制方法。通过算例及其结果分析,表明了方法的可行性和有效性。     

对我国乙烯工业发展的几点思考

阐述了世界乙烯工业现状、发展特点以及新型工艺技术分析，重点对我国乙烯工业总体发展水平、生产、消费、进出口贸易作了详细的讨论。在此基础上对我国乙烯工业发展方向、方式和规划提出了建议。     

The part of the private sector in global water planning: the role of desalination

Water is the key to further development. The private sector is already playing a major role in looking into alternatives for a balanced water supply situation with the help of advanced technologies. We were generously given many Gardens of Eden, but only a few will survive into the next century. A worldwide campaign is necessary to show the scarcity of water. The United Nations Habitat II Conference in Istanbul, June 3–14, 1996, and the preceding IDA World Conference in Abu Dhabi on Desalination and Water Sciences, 18–24 November, 1995, are the immediate platforms on which international institutions and multilateral development banks can discuss this topic and help formulate an agenda for the next century.     

Local‐scale Benefits of River Connectivity Restoration Planning Beyond Jurisdictional Boundaries

Conservation planning aims to optimize outcomes for select species or ecosystems by directing resources toward high‐return sites. The possibility that local benefits might be increased by directing resources beyond the focal area is rarely considered. We present a case study of restoring river connectivity for migratory fish of the Great Lakes Basin by removing dams and road crossings within municipal jurisdictions versus their broader watersheds. We found that greater river connectivity could often be achieved by considering both intra‐jurisdictional and extra‐jurisdictional barriers. Focusing on jurisdictional barriers alone generally forfeited <20% (median = 0%) of habitat gains for those who value solely habitat gains within the jurisdiction, but >75% (median = 100%) for planners who value larger‐scale habitat gains. Similarly, cost savings tended to be between ?50% and +50%, but in some cases were very negative. Our study underscores the local‐scale benefits of broadening restoration investments, especially for decision makers of the Great Lakes Basin and contributes to a discussion of appropriate and efficient scales of conservation planning. Copyright © 2017 John Wiley & Sons, Ltd.     

Cable-direct-driven-robot (CDDR) with a 3-link passive serial support

Cable-direct-driven-robots (CDDRs) provided with a passive serial support represent an interesting and rising evolution of planar cable robots. The paper is devoted to present and analyze a novel CDDR robot. The robot consists in a fully actuated CDDR supported against loading normal to the motion plane with a 3-link passive planar serial manipulator. This hybrid structure combines positive features of both parallel and serial architectures, and prevents out-of-plane movements without the necessity for the robot to be supported on the motion plane. The adoption of a 3-link serial manipulator ensures a greater workspace area compared with similar structures that adopt a smaller number of links, and improves specific characteristics of their dynamics. Nevertheless undesired oscillations may occur since the serial manipulator is underconstrained. For this reason damping elements are inserted in the structure. Simulation examples are presented to demonstrate the novel CDDR concept and its dynamics. In addition, a strategy to select proper values of damping coefficients is presented.     

渠首水位实时调控模型——以船行灌区一支渠为例

很多大中型灌区在输配水过程中存在水位衔接不当的问题,加之田面高程存在起伏,使得灌溉时往往存在部分田面不能上水或受淹等问题。本文提出了空间灌溉率的概念,并利用GIS的三维分析功能研究了其与渠道渠首水位之间的关系。分析表明,空间灌溉率与渠首水位之间的关系符合Logistic曲线;针对船行灌区一支渠,得到该Logistic曲线的参数,并确定了一支渠渠首和干渠渠首不同空间灌溉率所需的水位,为灌区水位实时调控提供基础数据。