基于GIS的城市规划信息管理系统研究

我国正迈入快速城市化建设过程中,运用GIS技术手段来解决城市规划过程中的城市化建设进程信息整合管理,对于提高城市规划信息整合效率、避免重复建设、重叠规划、一库多建等城市规划问题有着积极意义。     

DTMB接收机对单频网覆盖地点概率估计的影响研究

提出一种DTMB接收机抗单频网回波干扰性能实验室测试方法.首先,测量系统工作模式下的射频保护率PR、0 dB回波最大延时dmax以及延时超过dmax时回波幅度最小衰减量Dmin,然后根据射频保护率PR定义计算出延时超过dmax时有用信号功率所占回波总功率的百分比.并基于理论六边形单频网模型研究了固定接收和移动接收下DTMB接收机抗单频网回波干扰性能在不同FFT窗口同步方法下对单频网覆盖地点概率估计的影响,仿真结果表明接收机特性对单频网覆盖率有重要影响.     

Metric inequalities for routings on direct connections with application to line planning

We consider multi-commodity flow problems in which capacities are installed on paths. In this setting, it is often important to distinguish between flows on direct connection routes, using single paths, and flows that include path switching. We derive a feasibility condition for path capacities supporting such direct connection flows similar to the well-known feasibility condition for arc capacities in ordinary multi-commodity flows. The condition can be expressed in terms of a class of metric inequalities for routings on direct connections. We illustrate the concept on the example of the line planning problem in public transport and present an application to large-scale real-world problems.     

Generalized Fourth-Order Decompositions of Imaginary Time Path Integral: Implications of the Harmonic Oscillator

The imaginary time path integral formalism offers a powerful numerical tool for simulating thermodynamic properties of realistic systems. We show that, when second-order and fourth-order decompositions are employed, they share a remarkable unified analytic form for the partition function of the harmonic oscillator. We are then able to obtain the expression of the thermodynamic property and the leading error terms as well. In order to obtain reasonably optimal values of the free parameters in the generalized symmetric fourth-order decomposition scheme, we eliminate the leading error terms to achieve the accuracy of desired order for the thermodynamic property of the harmonic system. Such a strategy leads to an efficient fourth-order decomposition that produces third-order accurate thermodynamic properties for general systems.     

MODELING HARVEST SCHEDULING IN MULTIFUNCTIONAL PLANNING OF FORESTS FOR LONGTERM WATER YIELD OPTIMIZATION

In this study, wood production and hydrologic functions of forests were accommodated within a planning procedure for separate working circles (areas dedicated to certain forest functions) that were delineated according to an Ecosystem‐Based Functional Planning approach. Mixed integer goal programming was used as the optimization technique. The timing and scheduling of a maintenance cutting (partial harvest) was the decision variable in the modeling effort, and an original formulation was developed as a multiobjective planning procedure. Four sample planning strategies were developed and model outputs were evaluated according to these strategies. Spatial characteristics of stands were considered, and used to prohibit the regeneration of adjacent stands during the same time period. Because of the positive relationship between qualified water production and standing timber volume in the forest, the model attempts to maximize qualified water production levels by increasing standing volume stocks in the forest through the delay of regeneration activities.     

航路规划中数字地图单元格代价计算模型研究

为了解决航路规划中使用的原始数字地图信息量不够全面的问题,结合反舰导弹航路规划的实际作战背景,建立了数字地图单元格代价计算的数学模型.该模型包含了地形高程代价、威胁危险代价、战略回避代价和搜索区目标存在代价等基本模型.通过该模型可以将原始数字地图转化为包含各种相关航路规划主客观信息的综合数字地图.     

可行三维航迹个体的生成算法

在遗传算法中,初始种群中个体的质量对遗传算法的收敛速度影响较大.本文在分析航迹规划约束条件的基础上,设计了一种初始航迹个体的生成算法,产生的三维航迹个体满足飞行器性能约束,并能避免撞山危险,比传统的随机生成算法产生的航迹个体具有较大的适应度.使遗传算法能有效避免冗余搜索,从而提高航迹规划的收敛速度.     

遥感技术在上海立体绿化调查与规划中的优点与局限分析

由于立体绿化对于改善城市环境具有明显效应,上海近些年来正在大力推广立体绿化。然而,立体绿化在调查与规划上面临着难以掌握现状和潜在资源的难题。在上海的应用中,使用高分辨率航空遥感影像有效解决了上述难题。实践结果表明,遥感技术具有较多优点,同时也存在一些局限性。对此进行了分析,并针对局限性提出了相关对策。     

一类多体系统非完整运动最优规划的拟牛顿算法

研究带有非完整约束的一类多体系统运动规划问题。多体系统中的非完整约束通常是由不可积的速度约束或不可积的守恒律引起。在系统动量和动量矩守恒情况下,动力学方程降阶为非完整形式约束方程,系统的控制问题可转化为无漂移系统的非完整运动规划问题。文中首先导出具有多体开链系统的非完整运动模型。利用最优控制理论和最优化技术,采用输入参数化的方法将连续的最优控制问题转化为离散的最优控制问题,提出一种非完整多体系统运动规划的拟牛顿算法。最后将该方法用于自由漂浮的空间三连杆机构,仿真结果验证了该方法的有效性。