3D Digital Survey of Iron Tie-Rods in Masonry Buildings: Cross-Sections Analysis and Error Estimation

Ancient iron tie-rods are handcrafted elements with large geometric irregularities, due to production techniques (they are shaped by hammering and linked by hot-forging) and corrosion processes. In common practice, their cross section (that is one of the main parameter to assess their strength) is manually measured on site with a manual caliber. By analyzing a set of detailed three-dimensional (3D) digital surveys of real ancient tie-rods, this study provide an evaluation of the errors made by in-situ manual geometric measurements. In particular, it shows that, in some cases, manual on-site survey is sufficiently reliable and has errors that fall below 10%. Moreover, it shows that when tie-rods have high corrosion levels in hidden zones (typically those close or within the retaining walls) the on-site survey of visible parts only may produce far greater errors that exceed 100%, leading to a strong overestimation of the cross-section of the tie. The ongoing study is a first step toward the definition of correction coefficients to be applied to the on-site manual measurements of ancient tie-rods, with the final aim to improve the reliability of structural analyses.     

Dynamical Assessment of the Work Conditions of Reinforcement Tie-Rods in Historical Masonry Structures

Tie-rods are essential structural elements, which have been employed for centuries in masonry historical buildings, either during the construction or in successive strengthening interventions, with the aim of containing dangerous horizontal actions. The actual work conditions of these tie-rods, which are strongly influenced by their load history, are difficult to be quantified theoretically, and an effective method for their measure is of great importance in order to ensure the efficiency of these elements during the time and the stability of the entire building. Common measurements are often carried out adopting models based upon significant simplifications, like, for example, hinges at the extremities. These assumptions, rarely represent the real work conditions for anchorages. In this work, a non-destructive testing method is presented, based upon sophisticated dynamical models that can take into consideration many of the circumstances neglected by the simplified models. Four case studies are extensively described, trying to embrace the most common situations in term of peculiar features of the building, structural configuration, and load history. The discussion of the results yields the safety margin of the rod with respect to the material failure and provides important indications about the overall stability of the whole building.     

How Political Support Influences Red Tape through Developmental Culture

This study examines the interrelationship between external political support, internal organizational factors, and red tape, using a sample of information managers from state health and human service agencies. The study defines a red tape model and tests the model by structural equation modeling method. The study finds that political support has a direct effect on red tape. The higher the political support, the lower the level of red tape. The study also confirms an indirect effect of political support on red tape, mediated by developmental culture. Indirect effect through goal clarity has the correct sign but is not statistically significant. Practical recommendations are made for the political environment to provide the opportunity for managerial reforms that are often advocated.     

An Automatic Modal Identification Procedure for the Permanent Dynamic Monitoring of the Sanctuary of Vicoforte

ABSTRACT

The interest in automatic modal parameter extraction techniques has increased significantly in recent years because of the rising demand for Continuous Structural Health Monitoring (CSHM) of civil structures and infrastructures. The wider use of CSHM is related to its capability for early damage detection and therefore to its usefulness for planning maintenance and strengthening interventions. This article presents the main steps followed in creating a robust routine to run on an online basis the first-ever Continuous Vibration-Based Structural Health Monitoring (CVB-SHM) of a large masonry oval dome, i.e., the dome of the Regina Montis Regalis Basilica, also known as Sanctuary of Vicoforte. The procedure uses an output-only stochastic subspace identification method complemented by an automatic analysis applied to identification results, which are typically provided in terms of stabilization diagrams. In this study, the fully automatic procedure also includes a hierarchical clustering algorithm to separate authentic from spurious modes.     

China's Infrastructure Investment Boom and Local Debt Crisis

A noted Hong Kong-based economist addresses the emerging financing problems prompted by debt-laden local governments in China in the aftermath of the global financial crisis. More specifically, using the most recent data available, he traces the root of China's local debt overhang to a protracted debt-financed infrastructure investment boom in which several key institutions (the cadre evaluation system, the land management regime, and the banking sector) have created an environment that draws local governments into a land-infrastructure-leverage trap. The author argues that the resulting high levels of debt may ultimately impede the country's efforts to mitigate structural imbalances in its economy. Journal of Economic Literature, Classification Numbers: H600, H700, P200, P300. 3 figures, 9 tables, 121 references.     

Why are cultural policy decisions communicated in cool cash?

In this article, we analyze the role of the economic rationale in modern cultural policy decision communication and ask why it remains such an important factor, even though research has argued against it. Based on Luhmann’s system theory, we show how the economic rationale manifests itself in the cultural political communication as parasitic and complementary couplings, and how different communication forms are in play: the indirect, direct, and the both-and form. The point is to construct communicative positions in cultural policy. The positions involve the economic rationale in their own particular way and each of them offers themselves as a communicative platform which the culture politician can optionally step into and out of. The arts system stands out from other systems by not distinguishing itself in one single distinction and coding. In exactly this issue lies the communicative complexity which the communicating cultural politician faces and must handle. As our analysis shows, this complexity is handled by communicating within the economic rationale and coding, with the result that complexity is reduced.     

论我国城市开放空间系统的优化

城市开放空间系统优化是强化生态城市建设,进而推动城市可持续发展的重要途径。本文讨论了我国城市开放空间系统优化的重大意义,指出:城市的可持续发展强烈呼唤生态城市建设,而生态城市建设必须以城市开放空间系统的优化为支撑。解析了城市开放空间系统的空间形态结构和要素组成结构,阐明了开放空间系统的实用功能、生态功能、文化功能、景观功能和调控功能等,提出了城市开放空间系统优化的理论基础和应遵循的基本原则。在此基础上,着重论述了城市开放空间系统优化的基本对策和空间布局结构优化、圈层一体化优化、系统要素优化等主要工作内容。     

制度变迁与中国城市的发展及空间结构的历史演变

我国的城市发展水平同经济发展水平的偏离,说明对城市发展及其空间结构演变分析不能仅局限在物质经济领域,需要我们寻求影响城市发展及其空间结构变化的新因素一制度因素,把制度作为影响城市发展及其空间结构的一个主要的变量,来对此加以解释。为此,本首先构建了“制度变迁一城市发展变化”的理论框架,然后用该理论从宏观和微观两个方面来检验1949-1998年间制度变迁对城市发展及其空间结构的影响。与西方国家的以市场经济为主要动力驱动型的城市发展模式不同,中国城市的发展及其空间结构的演变在很大程度上是制度变迁而诱致的结果。但不同的制度对城市数量增长、组织体系及空间布局和对城市空间结构演变的作用力度又不尽相同。改革开放后,由于制度变迁带来的激励作用,中国城市获得了快速发展,城市空间结构快速变化。但与此同时,中国城市化的发展水平与相同发展条件下的世界城市化水平的差距却在拉大。而且随着市场经济体制的逐步完善,影响城市增长及空间结构的演变力量的因素越来越趋于分散化,制度变迁对城市发展所带来的激励作用正在弱化。为适应新世纪我国城市发展的战略目标,需要进行体制创新,为中国城市的发展及其空间结构的演变提供新的制度支持。     

SEM在中国旅游研究中的方法论应用问题

本文使用元分析的研究方法,选取发表在《旅游学刊》、《旅游科学》、《旅游论坛》和《北京第二外国语学院学报》上的42篇关于结构方程模型（SEM）应用的文献进行分析。重点围绕样本容量、测量变量、模型评价以及研究局限等4个方面讨论SEM在中国旅游研究应用中的方法论问题,并在此基础上提出若干改进意见。     

我国农村救护车资源布局优化:以河南省郸城县为例

优化农村救护车资源的配置有助于缩短急救服务的响应时间,对于维护重症伤(病)员的生命安全具有重要意义。本研究以河南省郸城县为例,将15分钟作为急救车路上所需响应时间,研究了该县当前救护车资源布局下农村居民的可达性;应用ArcGIS中的p-中位模型优化了郸城救护车布局点,并运用SPSS16中的配对样本t检验对比了优化前后郸城居民救护车服务可达性变化;应用ArcGIS中的最小覆盖面模型求解了覆盖郸城县域所需的最少救护车布局点数。研究显示,通过优化能有效提高居民的救护车资源可达性,在县域范围内布局13个左右的救护车资源能基本覆盖所有居民点。这一数量对与郸城具有相似自然社会背景的黄淮海平原县域具有借鉴意义。最后,文章还讨论了研究存在的局限。