Planning collision-free trajectories in time-varying environments: a two-level hierarchy

We propose a two-level hierarchy for planning collision-free trajectories in time varying environments. Global geometric algorithms for trajectory planning are used in conjunction with a local avoidance strategy. Simulations have been developed for a mobile robot in the plane among stationary and moving obstacles. Essentially, the robot has a global geometric planner that provides a coarse global trajectory (the path and velocity along it), which may be locally modified by the low-level local avoidance module if local sensors detect any obstacles in the vicinity of the robot. This hierarchy makes effective use of the complementary aspects of the global trajectory planning approaches and the local obstacle avoidance approaches.     

A parametric interpolator with confined chord errors, acceleration and deceleration for NC machining

Parametric interpolation has many advantages over linear interpolation in machining curves. Real time parametric interpolation research so far has addressed achieving a uniform feed rate, confined chord errors and jerk limited trajectory planning. However, simultaneous consideration of confined chord errors that respect the acceleration and deceleration capabilities of the machine has not been attempted. In this paper, the offline detection of feed rate sensitive corners is proposed. The velocity profile in these zones is planned so that chord errors are satisfied while simultaneously accommodating the machine's acceleration and deceleration limits. Outside the zone of the feed rate sensitive corners, the feed rate is planned using the Taylor approximation. Simulation results indicate that the offline detection of feed rate sensitive corners improves parametric interpolation. For real time interpolation, the parametric curve information can be augmented with the detected feed rate sensitive corners that are stored in 2×2 matrices.     

扬州芍药

研究扬州芍药的栽培简史,明确扬州芍药的历史地位,通过对扬州芍药现状的了解,提出积极措施,努力恢复扬州芍药的园艺地位.     

空间的塑造--厦门海湾公园设计

海湾公园利用植物、地形、大海与湖泊的周边环境等景观要素,运用隐喻、对比的手法,创造丰富、神秘、变化的空间,注重空间灵活的使用功能及其良好的人性化.     

中国城市土地利用结构优化研究述评

城市土地利用结构的确定和优化是城市总体规划的核心内容，从土地使用制度变迁，学科交叉，数理模型方法三方面回顾了中国城市土地利用结构优化研究的发展历程，分析了中国城市土地利用结构优化研究的新气象。在此基础上，指出当前研究工作的不足和问题，并提出未来研究的方向。     

A Multi-Objective Hybrid Genetic Based Optimization for External Beam Radiation

A multi-objective hybrid genetic based optimization algorithm is proposed according to the multi-objective property of inverse planning. It is based on hybrid adaptive genetic algorithm which combines the simulated annealing, uses adaptive crossover and mutation, and adopts niched tournament selection. The result of the test calculation demonstrates that an excellent converging speed can be achieved using this approach.     

混沌优化方法在灰色非线性水环境规划中的应用

通过把灰色参数和灰色变量视为混沌变量，利用混沌运动的遍历性、随机性、规律性以及对初值敏感性的特点，尝试应用具有优秀随机搜索性能的混沌优化方法求解水环境灰色非线性规划问题。实例研究证明，该方法具有搜索速度快、求解精度高的优点，因此对目标函数的优化结果比常规数值解法、遗传算法更加有效。     

浅谈城市道路立交的概念性方案设计

通过南昌市某快速路的设计实例，认识到搞好快速路沿线各交叉口的方案设计是快速路规划设计的关键内容。道路交叉口设计应注重交通功能分析，满足路口交通需求，同时也不能忽视立交的景观要求。     

信息化在传统企业管理中的应用

就山西大同齿轮集团有限责任公司在生产管理方面进行改革的尝试 ,从企业概况、项目规划、系统组织、实施组织、应用过程、效益体会几个方面做了阐述 ,提出运用高新技术、实施信息化系统是传统企业发展之路     

生活污水用于园林绿化的实验

通过对11种在天津石化公司有代表性的绿化植物10年来应用生活污水的跟踪调查及进行的相关实验证明,直接应用生活污水浇灌绿化植物,对绿化植物生长及对环境造成的负面影响不大.根据实验结果认为,生活污水可以有条件地用于园林绿化,并应注意密切跟踪调查.