海洋产业集聚水平测度及影响因素

海洋产业集聚可以推动区域经济发展。文章使用沿海11个省(自治区、直辖市)的面板数据,采用区位熵法测度海洋产业集聚水平并采用固定效应模型对海洋产业集聚的影响因素进行实证分析。研究发现：(1)海洋产业集聚存在明显的空间异质性。形成以海南、福建为主的第一产业集聚区,以天津为龙头的第二产业集聚区和以上海为领先的第三产业集聚区。海南、天津和上海作为我国海洋产业的强集聚区但集聚水平有所减缓。(2)资源禀赋、潜在市场、劳动力规模、对外开放程度和固定资产投资均显著提升海洋产业集聚水平。海洋科技创新水平不足导致对第二产业的发展不能形成有力支撑,高学历型人才的缺乏制约了海洋各产业的集聚化发展,第二、第三产业的发展已经不再依赖于传统的基础设施。应因地制宜发展优势产业并适度控制集聚规模,加快海洋科技创新和人才队伍建设,推动海洋产业集聚化发展。     

电气-几何模型在雷击风险评估中计算Cd值的应用

雷击风险评估中,考虑周围物体对评估目标物直接雷击次数的影响而引入了位置因子Cd,若Cd取值不能真实反映影响程度,将导致评估结果出现较大误差。本文利用电气—几何模型,根据周围物体和评估目标物高度以及两者的间距,按照绕击的计算方法,计算最大绕击电流Im,进而求得大于Im雷电流概率P,位置因子Cd取值确定为（1-P）值。     

贵州省旅游业区位重构研究

基于王瑛、王铮(2000)提出的旅游业区位模型,在考察了贵州省旅游景观分布后,本文修正了他们的模型,并划分了旅游业区位带:风景名胜带;奇异风光带;特色资源带;差异突出的文化与自然风光带。旅游业的这种空间机构类似杜能模型,但决不是杜能现象而是新地理现象。本文强调,贵州省以舞阳河为代表的喀斯特地貌景观属于青年期,在形态结构上不同于云南以石林为代表的壮年期地貌和广西的以桂林为代表的老年期地貌,是一种新的旅游地貌资源,需要突出资源特点开展营销。根据新的区位模型,本文讨论了贵州省旅游业区位,并且提出3条建议:通过建设高速公路将原来行程9小时的路程缩为6小时的;以舞阳河风景区为中心组织特色资源区;建设航空港发展一些资源条件好的地区为旅游亚中心。     

基于机器学习算法的银川台阵资料自动化震相分析和定位

近年来快速发展的机器学习算法显著提高了震相拾取的精度和效率。采用卷积神经网络和递归神经网络的震相识别方法对银川台阵2019年6～7月的连续波形数据进行事件检测和P、 S震相拾取,并通过快速震相关联和事件定位得到了银川地区较全的地震目录。结果表明,当震相数小于10时,虽然可以检测出较多事件,但分布呈弥散状,与区域地震活动特征不符。进一步对震相数≥10的事件进行了人工复核。总体而言,随着震相数量的增加,事件的误检率逐步降低。震相数16是该地区自动检测和定位结果准确性的拐点。当震相数≥20时,全部召回了地震目录中的13个地震事件,二者平均定位差异4.27 km。经过人工复核,检测到的真实地震事件为区域内地震目录中事件数量的9倍。本文使用的基于机器学习和快速震相关联和定位方法的流程可在确保准确率的基础上降低人工检测的难度,提高地震检测的效率。     

低纬子午环配备CCD相对定位精度的估计

本文给出了利用计算机模拟方法对低纬子午环配备CCD探测器进行高精度测量中CCD相对定位精度的估计,并对所得到的结果进行了初步分析。     

兰州市商业中心的区位格局及优势度分析

本文试图以兰州市为例,就商业中心区位的最优选择与配置、共演化动态及未来对策等进行定量分析与探讨。     

Source location variability and volcanic vent mapping with a small-aperture infrasound array at Stromboli Volcano,Italy

Stromboli Volcano in Italy is a persistently active, complex volcanic system. In May 2002 activity was confined to 3 major summit craters within which several active vents hosted multiple explosions each hour. During a 5-day field campaign an array of 3 low-frequency microphones was installed to investigate the coherent infrasound produced by degassing from these vents. Consistent phase lags across the 3 stations indicate distinct sources that are subsequently investigated to determine the associated vent location, apparent depth, and origin time. The cross-correlation routine allows for variations in comparison window length, waveform filtering bandwidth, and correlation and consistency thresholds, allowing for improved detection of certain types of degassing sources. Identification of activity at the various vents could be subsequently corroborated with 3 channels of synchronously acquired thermal data and video. During the May 2002 experiment persistent, energetic infrasound was observed from a passive degassing source within the Central Crater (CC) and transient infrasound, produced by discrete Strombolian explosions, was identified at 4 additional vents. The continuous infrasound produced by the CC exhibits variable frequency-dependent correlation lag times that are interpreted as a diffraction effect due to the acoustic radiators recessed location within a steep-walled crater. Such dispersion has important implications for accurate eruption source modeling because it indicates that infrasonic waveforms may be significantly filtered during propagation. Transient explosion signals from the Northeast Crater (NEC) and Southwest Crater (SWC) vents also exhibit dynamic correlation lag times, but this scatter may be more reasonably attributed to variable epicentral locations. Explosions from the NEC west vent, for instance, appear to emanate from a diffuse zone with a lateral extent in excess of 10 m.Editorial responsibility: R. Cioni     

New urban settlements in a perspective of public and private interests. Case study: a Swedish municipality within the hinterland of the Stockholm city

The changes of land use patterns and urban structures could be seen as the dynamic result of the trade off between public and private interests. Thereby the land use change is to some extent unpredictable. The focus in the current study is to measure the importance of spatial location factors regarding new residential and commercial buildings in relation to existing urban amenities and political guidelines. The relative importance of the location factors was studied by multinomial regression analysis. Results from this study reveal that the location profiles of new urban object types attained here indicate strong correspondence with local political land use guidelines and to clustering. The spatial distribution of new urban settlements does not in general correspond to the monocentric urban scheme where firms and residents locate in spatial proximity to urban centres.      

基于社区活动的自然保护项目优先度确定

准确选择项目社区及优先干预领域,是成功实施自然保护项目的基础。当前自然保护项目优先社区及活动的选择,主要沿用20世纪80年代早期形成的农村快速评估（RRA）和参与式农村评估（PRA）等方法,这些方法源于农村扶贫开发项目,倡导以社区为主的决策机制,但在自然保护项目中并不能很好地平衡保护和发展的关系,也无法突出自然保护目标和特点。本文在详细分析沿用传统参与式方法不足的基础上,综合考虑周边社区社会经济发展和自然保护区生物多样性保护的需要,结合参与式制图和参与式地理信息系统技术的研究进展,首次提出区位关系分析法。新方法以周边社区在自然保护区内的生产活动为分析对象,构建了确定项目社区和活动优先度的指标及算法。通过调查统计周边社区各类活动的频度f、强度S和面积A,计算社区对保护区的总体影响P,确定项目社区优先度;通过求算项目社区各类活动对自然保护区的影响Pj,结合同类活动对社区社会经济的贡献率Cj或对农户生计的重要值Ij,建立2×2交叉矩阵,确定项目活动优先度。除自然保护项目开发设计外,区位关系分析法可用于保护区的日常监测和管理,对提升保护成效具有参考意义和实践价值。     

光谱波长位置的确定

波长位置在光谱工作中至关重要。本文讨论和介绍了利用恒星光谱谱线、夜天光谱线、大气吸收线及摄谱仪标准谱灯谱线确定波长位置的方法。