SIMULATION OF THE FOURIER PHASE SPECTRUM FOR THE GENERATION OF SYNTHETIC ACCELEROGRAMS

This study presents the application of a new method for generating synthetic accelerograms based on statistical distributions for Fourier phase differences and Fourier amplitudes as functions of earthquake magnitude, hypocentral distance and site geology. Two important characteristics of the methodology are that it requires a small number of input parameters and that ground motion time histories can be simulated without any specific modulation function. Two areas with different tectonic patterns (North-Eastern and Central Italy) were selected for the application. The results of our analysis are reliable in the case of Central Italy because the data set is large and quite uniformly distributed, while for North-Eastern Italy our results should not be used for distances greater than 30 km.     

GENERATION OF ARTIFICIAL EARTHQUAKE MOTION RECORDS USING WAVELETS AND PRINCIPAL COMPONENT ANALYSIS

In the last century alone two to three million people died in earthquakes; More than 240 000 perish in Tangshan earthquake in China, 20 000 in the Izmit [Ikeya, 2004] 50 000 in India Bhuj earthquake, 100000 in Sumatra and 90000 in Pakistan earthquakes. Earthquake engineering has progressed to the stage where it is now computationally practical and desirable to perform a dynamic analysis of most civil engineering structures. Such an analysis requires the engineer to create an accurate analytical model of the structures as well as prescribe an earthquake input excitation. The design earthquake input excitation for the site under consideration is usually prescribed in the form of response spectra or in the form of an ensemble of artificial earthquake acceleration time histories. There is every need for generating artificial accelerograms since recorded accelerograms are very limited at site. This paper proposes five neural network based models for the generation of artificial earthquake and response spectra using wavelet transforms (WT) and principal component analysis (PCA) where the recorded accelerograms are limited at site of interest. The proposed model is compared with Lee and Han's model. The data for 25 earthquakes are taken for training and 4 for testing. Just like response spectra, this is also a convenient way of obtaining the design solution to a structural dynamics problem and is certainly an important tool.     

ARTIFICIAL ACCELEROGRAMS REPRESENTATIVE OF THE DAMAGE DISTRIBUTION ON A LOW-RISE SHEAR WALL

This study attempts to reproduce in an artificial way, at a given magnitude-distance couple, the statistical characteristics of damage caused by real accelerograms. The structure adopted is a low-rise shear wall, modelled as a nonlinear, one degree of freedom system with a degrading frequency as a function of a non-cumulative damage variable. Strong-motion records, contained in a large database, are characterised in terms of seismological and seismic parameters. Artificial accelerograms are generated from response spectra representative of real accelerograms belonging to different magnitude-distance zones. Although the mean damage is consistent, the low dispersion of damage caused by the artificial accelerograms with respect to that caused by the real accelerograms is highlighted. In order to reproduce the damage dispersion in addition to the mean damage, a generation method of representative artificial accelerograms is proposed. This method introduces the standard deviation drawn from attenuation relationships into a dispersion pre-process with respect to the regressed spectrum at a given magnitude-distance point. The method turns out to be capable of reproducing the statistical features of damage produced by real strong-motion records.     

USING GIS IN THE PROBABILISTIC ASSESSMENT OF EARTHQUAKE TRIGGERED LANDSLIDE HAZARDS

Summit Ridge, located in the North Santa Cruz Mountains, California, was heavily affected by landsliding during the 1989 Loma Prieta earthquake (M_w=7.0). Widespread shallow failures, along with 17 deep-seated landslides, caused extensive damage. In order to study possible methods of assessing landslide hazard a geographical information system (GIS) was utilised. Geological, geotechnical, geomorphological and seismological data were used in a deterministic analysis using two standard earthquake slope stability models (pseudo-static and Newmark displacement). The models were used to assess the landslide potential that existed during the Loma Prieta event. It was found that, of these two models, the Newmark displacement model proved most successful at predicting the location of shallow unstable slopes. However, because both models are deterministic in nature they did not take into account any of the error and uncertainty in the input parameters. Therefore, a probabilistic Newmark displacement method of analysis was developed. This was achieved by incorporating the principles behind a recently developed probabilistic technique which utilises the pseudo-static slope stability model. The method calculates the probability that a slope will exceed a certain critical value of Newmark displacement and thus fail. The use of such an analysis resulted in a more realistic distribution of hazard when compared with the distribution of actual landslides triggered by the 1989 earthquake. Subsequent to this, the probabilistic method was used to undertake a landslide hazard assessment for Summit Ridge given a postulated earthquake located on the Northern East Bay segment of the Hayward fault.     

ANALYSING THE VINLAND MAP: A CRITICAL REVIEW OF A CRITICAL REVIEW*

In an attempt to validate the Vinland Map as a genuine15th century work, Garman Harbottle (2008 ) claims to review critically, and thereby discredit, the archaeometric research undertaken on the Map's ink by Walter McCrone (1974–1999) and Brown and Clark (2002 ). In this paper we outline and discuss the numerous arguments that are presented by Harbottle, all of which we find to be misleading or at best highly questionable.     

时间地理学研究现状与展望

概述时间地理学在欧美及日本的应用研究状况,重点论述时间地理学在中国城市地域研究中的应用情况,展望时间地理学可能的应用研究领域。     

THE WIND OF CHANGE: A REVIEW ARTICLE

The Wind of Change in Central Australia. By Frederick G. G. Rose. Deutsche Akademie der Wissenschaften zu Berlin; Volkerkundliche Forschungen. Band 5. Akademie, Verlag, Berlin, 1965. Pp. 1–363. Illustrated. Stiff paper cover. Price 56 DM.     

TOWARDS A NEW APPROACH TO ARCHAEOMAGNETIC DATING IN EUROPE USING GEOMAGNETIC FIELD MODELLING*

We introduce a new approach to producing secular variation curves for archaeomagnetic dating, using global geomagnetic field modelling techniques. Using published palaeosecular variation curves for five European locations as input, and a previous global model for regularization, we produce a model for the period ad 0–1900, which reproduces the input curves within their 95% confidence intervals, and successfully fits data from other regions in Europe. Our global model performs as well as a previous regional model, but additionally ensures consistency with physical constraints. We show that the curves currently used for dating are not mutually consistent, and therefore that in the future this new approach will provide more reliable curves for archaeomagnetic dating.     

亲子旅游、亲子关系与儿童的旅游世界

2010年后,以独一代与独二代为主体的亲子旅游快速火热起来。但亲子旅游却是当前理论研究的薄弱环节。本文界定亲子旅游具有亲子性、共同性、目的性和引导性等特性,其旅游动机体现在加强儿童教育、促进家庭关系等两个方面。研究亲子旅游需要将其放置到当代家庭社会转型中,即家庭结构的变化和家庭关系的变化。展望指出,一是需要加强亲子旅游动机、需求及其决策行为研究;二是需要加强亲子旅游反身的亲子关系、家庭关系研究;三是研究儿童的旅游世界与成人的旅游世界之间的差异;四是需要采用针对性的儿童旅游研究方法。亲子旅游研究有助于推动旅游学科概念,以及旅游关系理论、旅游动机理论等相关理论体系的完善。     

西方高端人才跨国流动研究述评

基于文献分析法,对西方高端人才跨国流动研究进行述评,探讨其跨国流动的空间特征、动力机制和社会影响。跨国人才主要的流动方向为发展中国家流向发达国家,发达国家之间进行人才交换,以及发达国家向新兴工业化国家回流,在空间上高度集中在发达国家和新兴工业化国家的世界城市。其流动机制包括全球政治经济与文化转型、跨国流动渠道、政府管制以及流动者个体决策。其为流出地带来人才流失的困扰以及人才回流的红利,为流入地带来社会分化、居住隔离和种族排斥等社会问题。最后,就国内学者开展相关研究提出一些建议。     

A REVIEW OF MONASTERIES in Qamdo

WhenZelho,DirectoroftheQamdoCommunicationsBureau,wasinformedofOurintentiontovisitmonasteriesinQamdo,heimmediatelyarrangedforustohavetheuseofaPrinceDesertV-8,thebestmotorvehi-clelnthearea.WewerealsoluckyenoughtohaveBenbaCering,attachedtotheQamdoPrefeCturalUnitedFrontWorkDepartment,asourguide."TheBonreligionhasalonghistoryintheQamdoarea,andtheSagyaSectandtheGagyuSectwerethefirstsectsofFbetanBuddhismtoflourishinthearea,"explainedBenbaCering.'7heGarrnaMonasterywasthefirstmonasteryofthe…     

女性非正规就业研究述评

本文集中关注女性非正规就业的理论、类型、动因、特点、重要性、方式和群体差异,以及贫穷、全球化与女性非正规就业的关系,并探讨了非正规就业对女性的影响、女性非正规就业的对策等。在综合评述的基础上,概括出国外研究存在研究范围全球化、研究队伍壮大化、研究理论多元化、研究内容多样化的特点;指出了目前国内研究存在理论探讨少、缺乏本位主义思考、尚未形成一定的研究体系等不足。提出未来研究的关注点:国外理论的应用与我国特色理论的探索、归纳与总结,女性非正规就业集中的部门和区域的研究,女性非正规就业的政策与组织研究。     

《地缘政治参考材料》评介

中国科学院"国情与发展"战略研究组的《地缘政治参考材料》一书近日将印发,这是近年来地缘政治研究领域的代表性材料之一。     

A QUESTION OF IDENTITY: A REVIEW OF RECENT WORK ON BLACKS IN CANADA

In 2010 the US declared the Lake Erie water snake a recovered species, but in Canada the snake is still considered to be an endangered species. After explaining the legal similarities between the Ontario Endangered Species Act and the American Endangered Species Act, this article examines a case study with landowner interviews from one US island and one Canadian island. It is concluded that landowner attitudes toward conservation and private property are very similar. Thus, it is argued that bureaucratic differences, particularly institutional capacity and implementation styles, enabled the US but not Canada to recover the snake. The article concludes with a discussion of the need for better communication between the two countries for the purposes of biodiversity conservation.     

SOCIALIST FEDERALISM AND SPATIAL EQUITY: REVIEW OF A DISCUSSION

The proceedings of a wide-ranging discussion at the Institute of Geography, Moscow on current political and territorial issues in the USSR are summarized by one of its participants. The key thrust of the discussion centered on the need to find ways of increasing the involvement of Soviet political and other geographers in the analysis of critical questions of Soviet federalism: the incongruence of political-administrative boundaries with ethnic and economic regions; the search for a viable division of authority among Moscow, the republics, and local soviets; mitigation of growing regional inequality engendered by perestroyka and regional khozraschet (translated by Jay K. Mitchell, PlanEcon, Inc., Washington, DC 20005).     

MODELLING OF NONLINEAR DYNAMIC BEHAVIOUR OF A SHALLOW STRIP FOUNDATION WITH MACRO-ELEMENT

A new nonlinear soil-structure interaction macroelement is presented. It models the dynamic behaviour of a shallow strip foundation under seismic action. Based on sub-structured methods, it takes into account the dynamic elastic effect of the infinite far field, and the material and geometrical nonlinear behaviour produced in the near field of the foundation. Effects of soil yielding below the foundation as well as uplift at the interface are considered. Through the concept of macro-element, the overall elastic and plastic behaviour in the soil and at the interface is reduced to its action on the foundation. The macro-element consists of a non linear joint element, expressed in the three degrees of freedom of the strip foundation, reflecting the limited bearing capacity of the foundation. This model provides a practical and efficient tool to study the seismic response of a structure in interaction with the surrounding soil medium. Applications to a bridge pier show the potentialities of this kind of model.