Visual clutter reduction in zoomable proportional point symbol maps

ABSTRACT

Proportional point symbols are commonly used in map displays. However, when such displays are zoomed out, the available map space shrinks and consequently symbols overlap and the display suffers from visual clutter. Therefore, solutions are needed to reduce visual clutter in zoomable map displays that contain proportional point symbols. The authors add to the body of knowledge through the investigation of the performance of three solutions: aggregation of unit areas, the displacement of overlapping symbols, and modified symbolization; four variations of modified symbolization are examined in detail. The original study begins with a consideration of the strengths and weaknesses of the solutions, with an emphasis on information loss. Thereafter, user sessions with 165 participants are arranged to gain empirical evidence of the performance of the solutions. The results reveal that although participants zoom out the map to zoom levels that implement visual clutter reduction techniques, they tend to zoom in the map and pan it to examine specific areas. Moreover, they willingly use the map with aggregated unit areas in cases when the solution facilitates task accomplishment. A certain amount of skepticism attaches to the solution that displaces overlapping symbols.     

中国创意产业区理论研究的进展与问题

创意产业在中国发起于21世纪初的东部大都市,系统收集国内建筑学、产业经济学、人文地理学、区域经济学等学科的创意园区相关研究成果,评述中国自21世纪初创意产业兴起以来的基本概念研究、创意园区成长模式及机制、创意园区空间组织与园区规划、创意园与城市更新、创意园内部空间的研究进展。认为中国大城市内城产业升级与城市再生为创意园区的诞生与发展提供了历史契机。通过近8年努力,国内创意园区研究①已初步形成以创意园区成长模式与机理、创意园区规划建设、创意园区与城市更新为主的研究方向;②研究方法形成了以实证主义为主流的哲学基础;③研究队伍呈现以城市规划学、人文地理学等学科为主的综合交叉。同时,综述认为：中国对创意产业区相关概念认识不清,未能将集群的内核与创意产业的核心有机融合;其次是对于创意产业区的研究应坚持从微观的创意产业的某一类型,甚至是其一项目为分析单元,从制度、经济、文化等宏观方面诠释产业区内核的组织与发育过程;再次是中国创意产业区研究必须从创意经济和＂全球性—地方性＂博弈视野,探索创意产业区形成与演化的生境和其对城市发展—空间规划的空间效应（也即创意空间的生长）及城市响应策略研究。     

Analysis of Space-time Characteristics of Energy Field of Seismicity in Jiangsu and Its Neighboring Areas

The paper analyzes the variation characteristics of energy fields of seismicity 2.1≤M L ≤4.5 in Jiangsu and its neighboring areas during the period between January 1970 and December 2007.It also analyzes the variations of time "weight" coefficients of the major typical energy fields,using random function theory with seismic energy fields as a space-time random function field based on Empirical Orthogonal Function (EOF) expansion methods.The results show that the expansion accuracy of the first seven typical fields is 0.9244.The strength of seismic energy varies remarkably in different tectonic blocks in the study area.High value areas are in middle and southern Jiangsu,and the south Yellow Sea.The distribution of the typical fields also shows that it is an area that affects most significantly the seismic energy fields of the study region.The time "weight" coefficients of the first six typical fields vary with time,and the amplitude of the variations has strong temporal correlations with moderate-strong earthquakes in the region.     

卢龙地震动场的预测

分别用经验格林函数方法和随机方法对卢龙ML5.7地震的地震动进行模拟对比研究,结果显示:用经验格林函数方法模拟得到的波形和反应谱都与原始记录接近,用该方法模拟的地震动,无需掌握场地的具体情况;对于无小震记录的地区,如果知道了其场地情况与附近有小震记录地区相似,可以用该小震记录作为经验格林函数模拟地震动。对于不能用经验格林函数方法模拟地震动的地区,可以用随机方法模拟地震动。用随机方法模拟地震动具有简单、方便、无需小震记录的优点。根据卢龙场地具体条件,尝试用两种方法结合预测了卢龙地震加速度场,结果比较好地反映了断层周围加速度的峰值分布规律。     

Modeling the decommissioning cost of offshore wind development on the U.S. Outer Continental Shelf

The U.S. government requires renewable energy facilities installed in federal waters provide financial security to help ensure decommissioning obligations are carried out in the event the operator is unable to meet its obligations or goes bankrupt. The size of the bond is determined by the estimated decommissioning cost and is required prior to the approval of construction activities. The purpose of this paper is to develop decommissioning cost estimates for proposed U.S. offshore wind farms. Removal and site clearance cost are estimated across each stage of activity using empirical and hypothetical relations under current technology and market conditions without inflationary adjustment. Preliminary development plans characterize and define the system and serve as model input. A bottom-up approach based on operational stages is developed across removal, transport, processing and disposal activities. Disposal cost is calculated on a per ton basis and is estimated separately for each wind farm component. The model is parameterized with data from four proposed U.S. offshore wind farms and decommissioning costs are found to range from 115,000 to 135,000 $/MW, approximately 3-4% of estimated capital costs.     

EOF/PCA诊断气象变量场问题的新探讨

进一步论证了经验正交函数/主分量分析(EOF/PCA)在气象变量场诊断中的物理内涵,证明基于EOF/PCA的R型和Q型展开,可描述为气象变量场主要振荡型分解和主要空间分布型分解两种方案.前者表明,气象变量场的准周期振荡可分解为各主分量的周期振荡,它们各自等价于不同网格点(或站点)以其载荷为权重的迭加周期振荡,因此,气象变量场准周期振荡可视为来自不同周期源(网格点或站点)的准周期振荡逐层叠加的结果;后者表明,气象变量场的水平空间分布可视为各种主要空间分布型的叠加,而Q型展开才是对各种主要空间分布型的正交分解.由此深化了EOF/PCA气象变量场诊断的物理内涵.     

冬季黑潮延伸体海温异常结构及其与热带太平洋海温变化关系分析

基于NASA遥感系统提供的2003~2015年全球高分辨率海表温度资料,应用经验正交函数分析、时滞相关分析等方法,对北太平洋冬季黑潮延伸体区海温异常特征及其与热带海表温度的可能关系进行了初步分析。研究发现,冬季延伸体区的海温异常主要表现为两类结构特征,其一为上游区域发展型,包括海盆尺度一致性变化的季节模态和纬向反位相的收缩型结构;其二为纬向延展型,包括分叉东扩结构和通道东扩结构,且该两结构型在2010年前反位相,使得2006年前暖异常东扩路径基本控制在36°N以南,其后至2010年期间,暖异常东扩路径偏北,而2010年后结构型转为同位相,暖异常东扩路径偏北。分叉东扩结构表现为与热带海温变化紧密相关,进一步的时滞相关分析与合成分析表明,热带太平洋不同地区对中纬度海温分叉东扩的影响存在差异,Ni?o3区海温异常超前延伸体区分叉东扩模态约1~2个月,而Ni?o3.4区及Ni?o4区则与延伸体区海温分叉东扩保持前后各约3个月的宽谱同期负相关,或可表明El Ni?o的东部型和中部型对中纬度延伸体暖流分叉东扩存在超前和同期相关影响,且中部型影响更显著。     

An interatomic potential model for carbonates allowing for polarization effects

An empirical model for investigating the behaviour of CaCO₃ polymorphs incorporating a shell model for oxygen has been created. The model was constructed by fitting to: the structure of aragonite and calcite; their elastic, static and high-frequency dielectric constants; phonon frequencies at the wave vectors [&frac; 0 2] and [0 0 0] of calcite; and vibrational frequencies of the carbonate deformation modes of calcite. The high-pressure phase transition between calcite I and II is observed. The potentials for the CO₃ group were transferred to other carbonates, by refitting the interaction between CO₃ and the cation to both the experimental structures and their bulk modulus, creating a set of potentials for calculating the properties of a wide range of carbonate materials. Defect energies of substitutional cation defects were analyzed for calcite and aragonite phases. The results were rationalized by studying the structure of calcite and aragonite in greater detail.     

EOF和CCA方法在台风路径预报试验中的比较

利用气候持续性因子，并分别考虑了５００ｈＰａ高度场的ＥＯＦ因子和ＣＣＡ因子，分别建立了基于ＥＯＦ因子和基于ＣＣＡ因子的南海台风２４－１２０小时路径预报模式。经过非独立样本和独立样本的预报检验，比较。将两种方法运用于５００ｈＰａ高度场的分析表明，ＣＣＡ方法得出的典型变量权重系数分布虽不能象ＥＯＦ方法的特征向量一样表示出明显的而且平滑的空间场形式，但ＣＣＡ方法浓缩了更多的与台风路径整体相关性最好的原变