基于JASMIN框架的抛物方程有限差分解法并行计算及其应用

抛物方程有限差分解法的网格步长严格受波长限制,在求解城市小区电波传播问题时,计算速度明显变慢,为此,基于JASMIN框架研究了抛物方程有限差分解法的并行方法,通过将同一步进面划分成多个网格片,并分配到不同的处理器进行运算,实现了抛物方程有限差分解法的并行计算。与解析解的对比验证了并行程序的正确性,同时通过实例分析了并行程序的高效性,算例表明,抛物方程有限差分解法的求解效率得到了有效的提高。最后,模拟和分析了某一电信基站天线在包含9栋规则建筑物的城市小区环境中的电磁特性,结果表明,该方法能够得到基站在空间各处的信号覆盖强弱,可以为基站选址提供参考。     

改进蚁群算法的局部信息动态路径规划

针对传统蚁群算法收敛速度慢、对动态路径变化适应性低的局限性,提出了一种基于局部信息获取策略的动态改进型蚁群算法。该算法利用局部信息获取策略,进行最优局部目标点的获取,然后调用改进蚁群算法获取局部区域内的最优路径,再重复循环获取新的最优局部目标点,直到找到全局目标点。与此同时,将提出的改进型蚁群算法应用于动态路径规划中的路径寻优与避障,仿真结果表明：提出的算法在具有与传统蚁群算法相当的路径优化效果的同时,能够有效适应障碍变化、大大提高了路径规划的收敛速度。     

城市公园声景观危险度评价研究

针对城市公园声景观易受周围环境影响而损耗其景观价值这一问题,应用模糊层次分析法,通过自然、生活和机械3个准则层因素和17个指标层因素构建城市公园声景观危险度评价体系,以福州市闽江公园为例,研究城市公园声景观受负面影响因子损耗的可能性大小。结果表明,闽江公园声景观危险度总体评价结果为中度危险Ⅲ。指标层中,隶属极度危险Ⅴ的指标为修建施工声;隶属重度危险Ⅳ的为电闪雷鸣声;隶属中度危险Ⅲ的有:清洁机器声、大雨瓢泼声、车辆交通声、说话嬉戏声、狂风呼啸声、猫叫犬吠声、鞭炮烟花声、跳舞音响声和练嗓唱歌声;其余指标危险度均低于中度危险Ⅲ。评价结果符合实际,为今后城市公园声景观危险度研究提供了有效方法。     

城镇土地定级因素选择研究

本文通过对定级因素的相关性和土地等级空间结构的研究,得出已完成定级的城镇选择的定级因素存在普通的显著相关.进而确定商服中心萦华影响度和道路通达度为二个必选因素一般城镇选择3}4个定级因素评价土地级别即可满足定级目的的需要.这样可以减少土地定级工作量的50%以上,对推动土地定级估价研究工作具有十分重要的现实意义.     

基于时空多视图BP神经网络的城市空气质量数据补全方法研究

针对城市空气质量监测数据缺失的问题,提出一种基于时空多视图BP神经网络的数据补全方法。采用指数移动平均、普通克里金和非凸矩阵完备作为时空多视图特征,结合映射非线性关系的BP神经网络,构建数据补全模型。以北京市36个站点2014年5月1日至2015年4月30日监测的PM_2.5、PM₁₀、NO₂、CO、O₃和SO₂6种空气污染物小时浓度为实验数据。实验结果表明,在15%缺失率下,随机缺失补全的平均相对误差为0.102~0.154,时间连续缺失补全的平均相对误差为0.161~0.271,空间连续缺失的补全平均相对误差为0.108~0.155,优于典型的单视图预测方法和多视图线性预测方法。研究成果可为城市空气质量数据补全工作提供方法支持,研究思路可为时空数据挖掘提供参考。     

On solving large instances of the capacitated facility location problem

We present two sets of results pertaining to the solution of capacitated facility location problems that are large, especially with regard to the number of customers. One set of results relates to customer aggregation, while another set of results concerns the judicious selection of variable-upper-bounding (VUB) constraints to include in the initial integer-programming formulation.     

On the performance of universities in North Rhine-Westphalia,Germany: Government’s redistribution of funds judged using DEA efficiency measures

In Fandel and Gal (2001) [Fandel, G., Gal, T., 2001. Redistribution of funds for teaching and research among universities: The case of North Rhine-Westphalia, European Journal of Operational Research 130, 111–120] a solution for a real process of redistributing funds for teaching and research among the universities in North Rhine-Westphalia in Germany according to specific criteria was presented. The solution was based on aggregated proportional data and was determined by a negotiation process. Now that the absolute data with respect to the different subject areas of the universities are available, it is studied, to which extent the results of the redistribution can be justified by the relative efficiency measures using data envelopment analysis. Moreover, the inefficiencies or slacks, respectively, in the usage of personnel give reasons to reallocate the staff among the universities or to reduce it correspondingly.     

A fuzzy inexact two-phase programming approach to solving optimal allocation problems in water resources management

Inappropriate agricultural activities are the main reasons of water shortage and environmental pollution in many rural areas. How to generate preferred decision schemes for agricultural activities is a critical issue for decision makers. In this study, a two-phase programming approach is advanced for regional water resources allocation in a rural region of China. The approach shows applicability when the uncertain inputs are provided as intervals and such uncertainty is desired to be delivered to the corresponding solutions. Multiple control variables are introduced both in the objective function and constraints of the programming model, which make it possible for the constraints being relaxed under respective levels. A more satisfactory objective value can thus be expected as well as the impact of each constraint on the modeling outputs can be clarified effectively. The decision variables are useful for decision makers to justify and/or adjust the decision schemes for agricultural activities through incorporation of their implicit knowledge on water allocation management.     

长江三角洲城市体系中不同等级城市用地空间结构演变——以上海、杭州、无锡、慈溪为例

以多时相Landsat MSS、TM和ETM影像为数据源,利用遥感和GIS手段,提取不同等级城市（上海市、杭州市、无锡市和慈溪市）1979年、1990年、1995年、2000年和2005年5个时相的城市用地信息,分析了城市体系中不同等级城市用地空间结构演变特征.结果表明,不同等级城市的空间结构演变过程和扩展特征各不相同.