统筹城乡发展导向的中心村镇建设理论思考

统筹城乡发展战略为促进乡村空间重构、优化城乡格局提出了新要求。中心村镇是连接城市和散乱村庄建设的纽带,通过推进一定乡村地域的组织、产业和空间"三整合",可以有效利用各种资源,促进农村经济、社会和环境的协调与健康发展,中心村镇建设的科学规划与决策也亟需相关理论支撑。以乡村地理学、乡村规划学和乡村社会学等领域为背景,着眼于空间、时间和主体3个维度,对增长极理论、中心地理论、农业区位论、经济成长阶段论、空心村生命周期理论、社区(公众)参与等中心村镇建设相关理论进行梳理分析,探讨了这些理论在我国中心村镇建设与规划中的应用,认为中心村镇建设需要加强基础理论研究,分类指导我国中心村镇建设的实践。     

Lifecycle cost optimization of tuned mass dampers for the seismic improvement of inelastic structures

The seismic performance of tuned mass dampers (TMDs) on structures undergoing inelastic deformations may largely depend on the ground motion intensity. By estimating the impact of each seismic intensity on the overall cost of future seismic damages, lifecycle cost (LCC) proves a rational metric for evaluating the benefits of TMDs on inelastic structures. However, no incorporation of this metric into an optimization framework is reported yet. This paper presents a methodology for the LCC‐optimal design of TMDs on inelastic structures, which minimizes the total seismic LCC of the combined building‐TMD system. Its distinctive features are the assumption of a mass‐proportional TMD cost model, the adoption of an iterative suboptimization procedure, and the initialization of the TMD frequency and damping ratios according to a conventional linear TMD design technique. The methodology is applied to the seismic improvement of the SAC‐LA benchmark buildings, taken as representative of standard steel moment‐resisting frame office buildings in LA, California. Results show that, despite their limited performance at the highest intensity levels, LCC‐optimal TMDs considerably reduce the total LCC, to an extent that depends on both the building vulnerability and the TMD unit cost. They systematically present large mass ratios (around 10%) and frequency and damping ratios close to their respective linearly designed optima. Simulations reveal the effectiveness of the proposed design methodology and the importance of adopting a nonlinear model to correctly evaluate the cost‐effectiveness of TMDs on ordinary structures in highly seismic areas.     

水电全生命周期三维可视化数字管理平台研究

水电是清洁可再生能源,在我国能源结构中占有重要的地位.为更好地发挥梯级水电开发的社会经济效益,流域水电开发企业需要融合应用信息技术,实现梯级水电站全生命周期数字化管理.本文从流域水电全生命周期管理需求和流域水电企业信息化建设现状分析出发,提出了流域水电全生命周期三维可视化数字管理平台建设思路:通过企业数据中心建设集成整合已有信息系统采集管理的梯级水电工程相关阶段的信息资源,消除信息孤岛;通过三维可视化平台建设增强信息的直观表达,也便于分析和展现数据间的关联关系.这一思路已成功指导雅砻江流域数字化平台建设,可为相关流域水电数字化平台建设提供参考.     

25年来秦俑馆旅游生命周期与结构变化研究

将旅游地的成长看成是有生命的自组织过程,以1980-2005年统计数据,着眼陕西秦始皇兵马俑博物馆入境旅游、国内旅游、客源结构、人均消费及旅游收入的变化过程分析,从新角度探讨了旅游地的成长与结构变化的关系,丰富了对旅游地生命周期的认识。结果发现,秦俑馆入境旅游呈“扇贝型”增长,国内旅游为“主循环-再循环型”周期波动,入境游客在总游客中所占比例逐渐提高,人均旅游消费额不断提升,致使旅游经济收入摆脱了客流量生命周期的影响而得益延长,为我国国际名牌旅游产品从外延性客流量增长走向内涵型旅游收入增长提供了某些借鉴。     

基于供求关系的庐山旅游地生命周期驱动力分析

总结前人对旅游地生命周期影响因素的研究,基于经济供求视角,指出旅游产品的供求矛盾是影响旅游地生命周期演化的根本驱动力,构建了旅游产品影响因素的供求矛盾驱动模型。并以"世界文化景观"庐山为例,划分其生命周期阶段,分析各阶段的供求矛盾,验证了供求矛盾驱动模型的科学性和有效性。分析当前庐山旅游的供求矛盾,并提出相应的对策与建议。     

STATISTIC CHARACTERISTICS OF MCSS OVER ASIA AND WESTERN PACIFIC REGION

Mesoscale convective systems (MCSs) are severe disaster-producing weather systems. Previous attempts of MCS census are made by examining infrared satellite imageries artificially, with subjectivity involved in the process unavoidably. This method is also inefficient and time-consuming. The disadvantages make it impossible to do MCS census over Asia and western Pacific region (AWPR) with an extended span of time, which is not favorable for gaining a deeper insight into these systems. In this paper, a fire-new automatic MCS identification (AMI) method is used to capture four categories of MCSs with different sizes and shapes from numerical satellite infrared data. 47,468 MCSs are identified over Asia and western Pacific region during the warm season (May to October) from 1995 to 2008. Based on this database, MCS characteristics such as shape, size, duration, velocity, geographical distribution, intermonthly variation, and lifecycle are studied. Results indicate that the number of linear MCSs is 2.5 times that of circular MCSs. The former is of a larger size while the latter is of a longer duration. The 500 hPa steering flow plays an important role in the MCS movement. MCSs tend to move faster after they reach the maximum extent. Four categories of MCS have similar characteristics of geographical distribution and intermonthly variation. Basically, MCSs are zonally distributed, with three zones weakening from south to north. The intermonthly variation of MCSs is related to the seasonal adjustment of the large-scale circulation. As to the MCSs over China, they have different lifecycle characteristics over different areas. MCSs over plateaus and hill areas, with only one peak in their lifecycle curves, tend to form in the afternoon, mature at nightfall, and dissipate at night. On the other hand, MCSs over plains, which have several peaks in their lifecycle curves, may form either in the afternoon or at night, whereas MCSs over the oceans tend to form at midnight. Affected by the sea-land breeze circulation, MCSs over coastal areas of Guangdong and Guangxi always come into being at about 1500 or 1600 (local time), while MCSs over the Sichuan Basin, affected by the mountain-valley breeze circulation, generally initiate nocturnally.     

新时代煤炭资源全生命周期地质保障技术体系

新时代对煤炭行业提出了新要求,带来了新挑战、新机遇。在总结煤炭学者最新研究成果的基础上,中国煤炭地质总局提出了煤炭资源全生命周期的自主论述,将新时代煤炭资源全生命周期划分为绿色勘查、绿色开发、清洁利用和恢复绿色四个阶段,探讨了各阶段地质技术的相互关系、技术重点与特征,构建了新时代煤炭资源全生命周期地质技术工作框架,展望了主要攻关方向,为促进煤炭行业“安全、高效、绿色、智能”发展提供了地质保障技术思路。     

基于多阶段贝叶斯网络法的脐带缆全寿命周期可靠性分析

脐带缆是深海油气开发的关键设备之一,主要由钢管单元、电缆单元、光缆单元、护套及铠装单元组成。脐带缆在全寿命周期经过设计制造、储存、安装、在位运行、修复阶段,其每个阶段的可靠性并不是某个常数,而是随时间变化的函数,因此有必要对脐带缆全寿命周期可靠性的变化进行分析。建立某气田水下脐带缆在储存、安装、在位运行阶段的故障树模型,将其转化为多阶段贝叶斯网络模型进行建模分析,基于OREDA手册数据,假设部件寿命服从指数分布,对脐带缆存储、安装、在位运行阶段的可靠性进行分析,得到不同阶段脐带缆可靠性的变化曲线,并与可靠性框图方法进行对比分析。同时,通过引入条件可靠性对该方法进行了优化,分析脐带缆修复后的可靠性变化,以及对脐带缆关键部件进行重要度分析,针对薄弱环节提出改进措施。可靠性分析可为水下脐带缆的安全运行提供技术支持,同时也为海洋结构与设备的全寿命周期可靠性分析提供了一种方法参考。     

地籍实体的时间变化过程分析

宗地、土地证书和权利人是地籍信息系统中最基本的两个实体,宗地是土地证书的客体,权利人是土地证书的主体。宗地实体的生命周期实际上就是宗地空间形状及空间拓扑关系不发生变化的时间范围,土地证书的生命周期就是指土地证书客体以及土地证书主体都不发生变化的时间范围。在探讨地籍实体变更规律基础上,本文设计和研究了利用地理信息系统技术和数据库技术记录和回溯地籍实体随时间变化的方法。为地籍信息系统解决历史地籍信息管理提供了理论和技术基础     

Multiple hazard incidents lifecycle cost assessment of structural systems considering state‐dependent repair times and fragility curves

The performance and serviceability of structural systems during their lifetime can be significantly affected by the occurrence of extreme events. Despite their low probability, there is a potential for multiple occurrences of such hazards during the relatively long service life of systems. This paper introduces a comprehensive framework for the assessment of lifecycle cost of infrastructures subject to multiple hazard events throughout their decision‐making time horizon. The framework entails the lifecycle costs of maintenance and repair, as well as the salvage value of the structure at the end of the decision‐making time horizon. The primary features of the proposed framework include accounting for the possibility of multiple hazard occurrences, incorporating effects of incomplete repair actions on the accumulated damage through damage state‐dependent repair times, and requiring limited resources in terms of input data and computational costs. A dynamic programming procedure is proposed to calculate the expected damage condition of the structure for each possibility of the number of hazard incidents based on state‐dependent fragility curves. The proposed framework is applied to a moment‐frame building located in a region with high seismicity, and lifecycle costs are evaluated for six retrofit plans. The results displayed variation in the ranking of the retrofit actions with respect to decision‐making time horizon. Furthermore, the sensitivity analyses demonstrated that disregarding repair time in the lifecycle cost analysis can result in false identification of unsafe retrofit actions as optimal and reliable strategies. Copyright © 2016 John Wiley & Sons, Ltd.