Large-scale Facilities for Astronomical Observation

Driven by the rapid development of astronomical studies pursued by researchers at different astronomical observato riesunderits administration, the Chinese Academy of Sciences(CAS) has designed and built a series of large-scale facilitiesfor astronomical observations over the past four decades. Among them are some high-profile ones, represented by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) and the Five-hundred-meter Aperture Spherical radio Telescope(FAST).

PDBSCAN: Parallel DBSCAN for Large-Scale Clustering Applications

Density-based algorithm for discovering clusters in large spatial databases with noise(DBSCAN) is a classic kind of density-based spatial clustering algorithm and is widely applied in several aspects due to good performance in capturing arbitrary shapes and detecting outliers. However, in practice, datasets are always too massive to fit the serial DBSCAN. And a new parallel algorithm-Parallel DBSCAN(PDBSCAN) was proposed to solve the problem which DBSCAN faced. The proposed parallel algorithm bases on MapReduce mechanism. The usage of parallel mechanism in the algorithm focuses on region query and candidate queue processing which needed substantive computation resources. As a result, PDBSCAN is scalable for large-scale dataset clustering and is extremely suitable for applications in E-Commence, especially for recommendation.

Semi-supervised Affinity Propagation Clustering Based on Subtractive Clustering for Large-Scale Data Sets

In the face of a growing number of large-scale data sets, affinity propagation clustering algorithm to calculate the process required to build the similarity matrix, will bring huge storage and computation. Therefore, this paper proposes an improved affinity propagation clustering algorithm. First, add the subtraction clustering, using the density value of the data points to obtain the point of initial clusters. Then, calculate the similarity distance between the initial cluster points, and reference the idea of semi-supervised clustering, adding pairs restriction information, structure sparse similarity matrix. Finally, the cluster representative points conduct AP clustering until a suitable cluster division.Experimental results show that the algorithm allows the calculation is greatly reduced, the similarity matrix storage capacity is also reduced, and better than the original algorithm on the clustering effect and processing speed.

Probabilistic Distance, Capacity Clustering Location Model of a Semi-Obnoxious Facility, a Real Case of Tafo, Kumasi, Ghana

The collection of solid waste from third class communities in most devel-oping countries is by skip containers, however, the location of these facilities has been done arbitrary without any mathematical considerations as to the number of customers the facility is serving, the distance one has to travel to access it and thereby making some of these residences to dump their refuse in gutters, streams and even burn them. In this paper we proposed an improved probabilistic distance, capacity clustering location model which takes into consideration the weight of solid waste from a customer and the capacity of the skip container to locate the skip container to serve a required number of customers based on the capacity constraint of the container. The model was applied on a real world situation and compared with the existing practice in terms of average distance customers had to travel to access the facility. Our results gave a well shorter average travel distance by customers, gave a number of skip containers needed in an area based on their waste generation per capita.

On the Large-Scale Structure of the Universe as given by the Voronoi Diagrams

The size distributions of 2D and 3D Voronoi cells and of cells of Vp（2, 3）,--2D cut of 3D Voronoi diagram--are explored, with the slngle-parameter （re-scaled） gamma distribution playing a central role in the analytical fitting. Observational evidence for a cellular universe is briefly reviewed. A simulated Vp（2, 3） map with galaxies lying on the cell boundaries is constructed to compare, as regards general appearance, with the observed CfA map of galaxies and voids, the parameters of the simulation being so chosen as to reproduce the largest observed void size.

Collaborative planning approach for anti-bioterrorism emergency facility location based on aerodynamics

To smooth the correlation process from bio-virus diffusion to emergency relief response,the Gaussian plume model is used to describe the diffusion of dangerous sources,where the bio-virus concentration at any given point in affected areas can be calculated.And the toxic load rule is introduced to define the borderline of the dangerous area at different levels.Combined with this,different emergency levels of different demand points in dangerous areas are confirmed using fuzzy clustering,which allows demand points at the same emergency level to cluster in a group.Some effective emergency relief centers are chosen from the candidate hospitals which are located in different emergency level affected areas by set covering.Bioterrorism experiments which were conducted in Nanjing,Jiangsu province are simulated,and the results indicate that the novel method can be used efficiently by decision makers during an actual anti-bioterrorism relief.

Exploratory space data analysis of spatial patterns of large-scale retail commercial facilities:The case of Gulou District,Nanjing,China

This study uses methods,such as a nearest proximity index,nuclear density,spatial interpolation,buffering zone,and overlay analysis,based on an exploratory spatial data analysis tool.It focuses on a large commercial facility in which a mathematical analysis is conducted on its spatial patterns.In the study,45 large-scale retail commercial facilities(LSRCFs)in the Gulou District,Nanjing,China,were chosen,and the spatial concentration,density,and structure of the LSRCFs in this area were analyzed.Three additional factors,namely,population,transportation,and consumption,were examined to determine their impact on the spatial patterns of the LSRCFs.Finally,this study recommends a spatial layout for the future of the Gulou District according to the analysis results.

Mass-Temperature Relation of X-ray Clusters in Triaxial Halo

We investigate the mass-temperature relation of clusters for both the spherical NFW halo model and a concentric triaxial halo model. We study the temperature and density distributions of both an isothermal and a polytropic intra-cluster gas in hydrostatic equilibrium. We find that both the uncertainties in the concentration parameter and in the eccentricities (in case of the triaxial halo) lead to a greater scatter in the emission-weighted temperature at a given halo mass for less massive clusters. This may be helpful when determining the intrinsic statistical error of the σ8 normalization of the linear power spectrum from cluster abundance.

Resolved SZE Cluster Count

We study the counts of resolved SZE (Sunyaev-Zel'dovich effect) clusters expected from an interferometric survey in different cosmological models under different conditions. The self-similar universal gas model and Press-Schechter mass function are used. We take the observing frequency to be 90 GHz, and consider two dish diameters, 1.2 m and 2.5 m. We calculate the number density of the galaxy clusters dN/(dΩdz) at a high flux limit Svlim=100 mJy and at a relative low Svlim =10 mJy. The total numbers of SZE clusters N in two low-Ω0 models are compared. The results show that the influence of the resolved effect depends not only on D, but also on Svlim: at a given D, the effect is more significant for a high than for a low Svlim. Also, the resolved effect for a flat universe is more impressive than that for an open universe. For D = 1.2 m and Svlim =10 mJy, the resolved effect is very weak. Considering the designed interferometers which will be used to survey SZE clusters, we find that the resolved effect is insignificant when estimating the expected yield of the SZE cluster surveys.

Facility Location Decisions Based on Driving Distances on Spherical Surface

Facility location problems are concerned with the location of one or more facilities in a way that optimizes a certain objective such as minimizing transportation cost, providing equitable service to customers, capturing the largest market share, etc. Many facility location decisions involving distance objective functions on Spherical Surface have been approached using algorithmic, metaheuristic algorithms, branch-and-bound algorithm, approximation algorithms, simulation, heuristic techniques, and decomposition method. These approaches are most based on Euclidean distance or Great circle distance functions. However, if the location points are widely separated, the difference between driving distance, Euclidean distance and Great circle distance may be significant and this may lead to significant variations in the locations of the corresponding optimal source points. This paper presents a framework and algorithm to use driving distances on spherical surface and explores its use as a facility location decision tool and helps companies assess the optimal locations of facilities.

Clustering and merging for real-time forest rendering

Rendering of large-scale forest scenes is a challenging task, whose highly geometric complexity will put heavy burden on current graphics hardware. When navigating the scene, the overall visual result is generally considered as the core concern. A new method is proposed in this paper for large-scale forest rendering using clustering and merging strategies. Our method improves the rendering effect by clustering polygons according to the point information with relation to neighbours. A fast forest rendering system is developed accordingly. The relative techniques in the system can improve the visual quality on demand of different applications.

基于暴雨管理模型的长江流域丘陵城镇面源污染控制方案效果评估

随着我国长江流域城镇工业源和生活源污染控制的持续加强,面源污染贡献率明显增加,利用相关技术组合有效控制城镇面源负荷,已经成为长江流域城镇控制污染负荷和提升水体生态环境质量的主要内容。为探讨面源污染控制技术设施对长江流域丘陵地区城镇降雨径流降污减量的效果,以重庆市永川区新城区内某区域作为研究对象进行汇水区概化,并对其构建暴雨管理模型(SWMM)和进行参数确定及验证,采用该模型模拟透水铺装、绿色屋顶、雨水花园和下凹式绿地4种单项技术设施方案及其9种组合设施方案对研究区域降雨径流总量及污染物(包括SS、COD、TN、NH_(3)-N和TP)负荷削减情况;并采用基于群决策的层次分析法,从效益-经济-技术3个角度综合评估各种组合控制方案对降雨径流水量水质控制效果。结果表明:所构建的研究区SWMM模型的水文、水力参数率定结果误差小于1%,水质参数率定结果纳什效率系数均在0.7以上且误差平方均值(B%MSSE指数)接近于0,实现了模型参数本土化;在各降雨重现期下,4种单项技术设施方案中透水铺装对径流量和污染物负荷控制效果最优;基于效益-经济-技术3个角度综合评估组合方案,确定方案P7为研究区域面源污染削减最佳组合方案,即布设面积比例为35%透水铺装、30%绿色屋顶、7%雨水花园和30%下凹式绿地,其径流总量削减率达到29.4%,SS、COD、TN、NH_(3)-N和TP负荷削减率分别达到36.2%、35.1%、35.1%、30.6%和32.2%。

115份设施番茄表型性状遗传多样性分析

种质资源是新品种选育的根本。为筛选适宜云南省设施栽培的、农艺性状优良的番茄种质,本研究引进115份番茄种质,对其质量性状和数量性状进行了调查,并利用主成分分析、相关性分析和聚类分析对种质资源的遗传多样性和特征规律进行研究。本研究筛除了9份极易感病的番茄种质,余下的106份中筛选出86份抗病种质;106份番茄种质均为蔓生型,其果实形状及颜色比较丰富,共有3种果型、7种果色;植株长势整齐度高的种质共计15份,无裂果及裂果程度中等的种质共计35份。其中,番茄种质的心室数、单果重、首花序节位性状的变异幅度较大。相关性分析结果表明,株高与可溶性固形物含量、转色总台数、坐果总台数和总台数呈极显著正相关,与单果重和单株产量呈极显著负相关;茎粗与单花序坐果数、可溶性固形物含量、转色总台数、坐果总台数和总台数呈极显著正相关,与单果重和单株产量呈极显著负相关。聚类分析将番茄种质分为3个类群6个亚群,筛选出平均可溶性固形物含量高、平均单花序坐果数多和平均坐果总台数多的番茄种质共计47份;平均单株产量大于5.00 kg的番茄种质23份;平均单果重大于200.00 g的番茄种质9份。分析结果表明,番茄首花序节位越高坐果总台数越少;单果重越大,可溶性固形物含量越低,单株产量越高,单花序坐果数越少。果实横径、果梗洼大小、单果重、果实纵径和果肉厚度可作为评价设施番茄种质的主要因子。

人本视角的多层级城市医疗卫生服务设施可达性评价——以南京市为例

利用精细化的城市数据,本研究以居住小区为分析主体,通过多视角评估和居住单元聚类,分析城市医疗卫生服务设施的可达性。首先,以人为本的视角,基于现行医疗卫生服务体系,整合了城市和社区三个层级中提供居民日常保健服务的设施数据。其次,模拟居民视角,提出了丰富度、便利度和基于三步搜索法(3SFCA)的匹配度三项指标。针对南京市中心城区的实证研究发现,各项指标的评价结果在数量分布及空间分布具有显著差异,同时部分指标呈现出了跨层级的相关性。通过K-means聚类方法对居住单元进行分组,进一步揭示了医疗可达性的空间分布模式以及与居住人口特征的关系,为提升城市宜居性提出针对性措施。

基于核函数聚类的重庆市图书馆均等配置及优化

以重庆市图书馆为例,从居民视角出发,应用公共设施区位理论,提出了核函数聚类法,优化图书馆空间配置。引入多种优化模型,与核函数聚类法进行了对比分析,以期最大程度地优化重庆市图书馆的空间配置。结果表明:用不同方法进行图书馆空间配置优化,核函数聚类法覆盖的总人口数最多,受距离影响较小,优化的空间配置更均等;P-中心模型受空间分布影响较大;P-中位模型易受距离影响;MCLP模型较适合中距离优化的选择。模型间交通可达性的差异并不明显,可用于优化决策提供参考辅助。该核函数聚类法可为公共服务设施空间布局的均等优化或规划提供理论依据。

连锁运营模式下的社区养老服务设施现状及其合理配置研究——以首都核心区代表性连锁运营驿站组团为例

2021年底,我国已正式步入中度老龄社会阶段。社区养老服务设施作为居家养老、社区养老服务的依托,其合理配置是满足老年人服务需求的基本保障。以老龄化率居前列的首都核心区连锁运营模式下的代表性社区养老服务驿站组团为研究对象,对驿站布局与规模类型,服务项目、服务量与服务提供形式,人员安排与统筹调配情况,不同规模驿站的空间利用实态等进行调研;对服务量的影响因素、空间利用现状与问题等进行分析归纳,进而对连锁运营模式下社区养老服务驿站的规划布局、不同规模驿站功能与空间的合理配置提出建议,以期为优化社区养老服务设施提供参考。

基于知识图谱的我国城市公共服务设施公平性研究热点分析

公平公正地配置公共服务设施是城市规划的核心,我国从20世纪末期逐步开展针对公共服务设施公平性的相关研究,目前已形成较为丰富的研究成果。文章结合CiteSpace知识图谱分析和文本分析的方法,对近20年相关文献进行聚类分析和文献综合分析,从研究视角、研究内容、研究方法等方面探讨我国城市公共服务设施公平性研究的发展演变与热点问题。城市公共服务设施公平性研究从“物”的视角转向人本主义视角,基于多源数据、综合城市居民群体的社会经济特征与需求的社会公平研究成为未来的重点问题。

基于空间实体约束的空间聚类算法研究

空间实体的存在对空间聚类分析产生重要的影响,传统的空间聚类分析中没有考虑空间实体的约束作用,从而影响了聚类结果。本文在总结了以往的空间聚类算法的基础上,提出了一种改进的基于空间邻接关系的空间聚类算法,该算法将空间邻接关系和空间实体作为约束条件嵌入到整个聚类过程中,使得数据对象的归类受到"就近原则"和"约束条件"的双重限制。

产业集群视角下北京设施蔬菜产业发展的思考

农业产业集群建设是加快农业现代化、提升区域产业竞争力的重要路径。设施蔬菜作为北京都市现代农业最有代表性的产业,推进其集群化发展是北京实现农业现代化的主要任务。该研究从设施蔬菜生产现状、产业集中度、生产经营主体、科技支撑、服务体系与机制创新方面分析了北京建设设施蔬菜产业集群的基础,针对面临的主要问题,提出要优化产业布局、推进绿色发展、构建全产业链服务体系的设施蔬菜产业集群发展战略,并给出相关对策建议。

社会资本与集群中小企业融资便利——基于湖南汨罗再生资源行业数据的实证研究

以湖南汨罗再生资源行业企业集群的近200家企业为调查对象,考量集群企业社会资本的影响因子,结果表明,集群中小企业社会资本主要受企业家个人基本情况、企业的信用情况、企业的存续年数以及集群中小企业的合作程度等四个因子的影响。社会资本与集群中小企业融资的关系实证表明,社会资本对中小企业融资便利具有促进作用。