Natural Frequency of Single Pier Bridges Considering Soil-Structure Interaction

Because of the crucial role of free vibration frequency of a structure (e.g., a bridge) in design procedure, more realistic estimation of the frequency ends up in safer and more optimized design. As obtaining the free vibration frequencies of a bridge, considering soil-pile group-structure interaction, provide more realistic values, development of an analytical model to obtain such free vibration frequencies is studied in this research work. Most researchers have studied models with a single pile foundation. The purpose of this study is to assess soil-structure interaction (SSI) effects on dynamic performance of pile group supported bridges. A new analytical model is proposed to predict seismic analysis of these bridges. Applying the dynamic equations of motion for the system, SSI effects have been estimated. Based on the suggested analytical model, a new approximate equation is proposed for calculating natural frequency of pile group supported bridges. Equation accuracy has been investigated by comparing the results with those achieved by previous studies. Most periods calculated by the approximate equation are similar to those given for other case studies, indicating that the model could be applicable to other projects. Since the proposed model is very similar to real soil-pile-pier systems, this approximate equation can be used in preliminary seismic design of bridges.     

Spatial Competition and Bounded Rationality: Retailing at the Edge of Chaos

The spatial dimension of competition among retail outlets is well researched and typically captured with spatial interaction models. A stream of theoretical research has studied the consequences of incorporating various types of dynamics into these models. We build on this research by incorporating a behavioral decision process based on bounded rationality, and by allowing for unexpected adversity in the environment in the form of exogenous shocks. Given these characteristics—spatial competition, boundedly rational decision making, and environmental adversity—we study the long-run dynamics of a model retail industry. The model reaches a stochastic steady state which is “poised,” in the sense that a shock may—or may not—trigger a wave of innovation which sweeps the entire system. Detailed investigation of this steady state shows that it has the characteristics of a general type of organization, known as self-organized criti-cality, that has been described in both theoretical biology and statistical physics.     

New regression equations for stature estimation for medieval Scandinavians

Estimating stature from skeletal remains in an archaeological context requires appropriate methods that take into account possible temporal and spatial changes in body proportions. New regression equations—both least squares (LSQ) and reduced major axis (RMA) equations—were thus developed for estimating living stature from the long bone lengths of medieval inhabitants (N = 60) of Westerhus, Sweden. The living stature of these skeletal specimens was determined by using the anatomical method. Findings in this study reveal that LSQ regression equations systematically overestimate statures of short individuals and underestimate those of tall individuals, whereas the RMA equations—both combined sexes and sex‐specific equation—provide more accurate stature estimations for individuals of very different statures. The combined sexes RMA‐equations should be used for cases in which the sex is unknown because they provide more accurate stature estimations than sex‐specific equation with a wrong sex determination. These new equations are more appropriate than generally used regression equations for estimating statures of the medieval period Scandinavians. Copyright © 2009 John Wiley & Sons, Ltd.     

A transport interpretation of the growth of urban regions: an American example

In a seminal work on the evolutionary structure of wholesale trade published in 1970, Vance sharply attacked the mechanistic application of ahistorical central place concepts in efforts to explain the evolved form of urban systems in economically advanced regions. ^[1] As an endogenic model of highly localised tertiary interaction, Vance claims that central place theory is difficult to apply in old culture regions where the feudal inheritance provides some basis for cellular administrative organisation of small territories; moreover, as a paradigm for newly settled lands he sees it as historically inappropriate. ^[2] In regions such as North America, mercantilism forged powerful links between distant locations well before surrounding territory was well integrated in bureaucratic terms, and urban networks displaying central place characteristics arose only with later regional development and then only in selected areas of relative economic homogeneity. Thereafter, forces elaborating both mercantile and central place networks operated together, but central place systems always nestled within the larger-scale exogenous mercantile system.This reinterpretation of settlement history in new lands promises a fertile frame-work for understanding the complex historical layering of urban systems that still dominates their functional and locational structure. Vance's general proposition, however, needs evaluation in the light of empirical analyses of particular regions and time periods. This paper explores one aspect of transport provision (passenger service) in the American Midwest in the second half of the nineteenth century in an effort to assess the degree to which patterns of increasing spatial interaction and interdependency within the settlement system of the region can be interpreted in terms of Vance's mercantile model.     

The Future of Collective Farms' Built Social Infrastructure: Choosing Between Central Place and Network Theories

The aim of this paper is to discuss local and regional planning and development practices in a post‐socialist country such as Estonia. Two approaches — central places and network theories — are used as a conceptual basis. According to the first hypothesis, planning and development of social infrastructure (e.g. schools, sports halls) has remained based on the central place theory — as an outdated planning approach — in Estonia. The second hypothesis argues that while, on the one hand, the application of the network paradigm and increased cooperation between local communities would considerably save public resources, on the other hand, because of the path dependency of Soviet centralized planning and development practices, the networking and lobbying takes place vertically rather than horizontally. This restricts both administrative cooperation and networking on the local and regional levels. The paper consists of three parts. The first part describes the turn in Western planning theory: the shift from normative top‐down planning to a bottom‐up approach and networking. The second part analyses critically the Soviet and post‐Soviet planning theory and practices: the planning and development culture created during the Soviet era. Finally we present a case study of a community planning procedure in the Suure‐Jaani locality — a good example of the influence of historical changes in the settlement system and planning culture of the past on current development.     

文化旅游区游客涉入对地方依恋的影响测评

本文从游客涉入和地方依恋的维度层次出发,构建游客涉入对地方依恋的影响模型,以徐州汉文化旅游区为案例地,运用结构方程模型方法分析了文化旅游区游客涉入与地方依恋的结构性关系。研究结果显示,游客涉入对地方依恋有显著影响,具体表现为重要/象征性维度显著正向影响地方依赖;愉悦性维度显著正向影响地方依赖和地方认同;风险性维度显著负向影响地方依赖。地方依恋两维度间的关系也被证实为地方认同显著正向影响地方依赖。     

The Urbanization Process with Moving Boundary

The paper proposes a dynamic model of urbanization in the regional system consisting of the central business district (CBD), the urban, and the rural areas. Processes of “eating up” the rural land by the residents and firms in the urban area are endogenously determined. Spatial and temporal land prices of the urban and rural areas are described by partial differential equations. The boundary between the urban and rural areas is temporarily moved by “eating-up” forces of the urban area. Movement of the boundary is determined by interactions between the urban and rural areas near the boundary. The model consists of three partial differential equations under appropriate boundary and initial conditions. It describes how the actual regional pattern is disturbed far away from the equilibrium by inflationary forces. An analytic solution of the fixed rural land price is given.     

旅游消费者在线购买旅游产品的信任度、满意度及忠诚度研究

中国在线旅游市场方兴未艾,旅游消费者在线购买旅游产品的信任度、满意度及忠诚度已成为旅游业界和学界关注的重要课题。本文运用结构方程模型以考察对旅游消费者在线购买旅游产品信任度、满意度和忠诚度产生影响的因子以及各自的影响关系,其中,导航功能、安全感知、交易费用作为自变量,信任度和满意度作为中间变量,忠诚度作为因变量。通过社会调查收集数据并进行分析发现：导航功能、安全感知对信任度产生显著的正向影响;交易费用尽管对信任度并没有显著影响,但其通过中间变量满意度对信任度有间接影响;满意度对信任度产生显著的正向影响,而且两者都会对忠诚度产生显著的正向影响。     

Intrastate federalism in Australia

The article applies a distinction often used in the study of Canadian federalism—intra‐versus interstate federalism—to the Australian federal system. The intrastate federalism model focuses on the representation of state, regional and local interests directly within central government institutions. On the surface the model appears to have little applicability to Australia. However, the examination of selected Commonwealth institutions and arenas, primarily the cabinet and party system, indicates that intrastate practices may in fact be much more pronounced in Australia than what is generally supposed. There are networks of influence at work outside the confines of standard intergovernmental arenas, networks that at times can be used to advantage by state governments or by state or local interests, at other times by the Commonwealth to enhance centralised control or even to undermine the status of state governments as legitimate actors within the Australian federal system.     

On children's independent mobility: the interplay of demographic,environmental, and psychosocial factors

In the past 50 years, a marked reduction has occurred in European and North American children's freedom of movement and outdoor play. Using a structural equation model, the present study investigates the interaction between personal, environmental, and psychosocial factors that affect children's independent mobility. The study involved 313 mothers of 8–10-year-old Italian children. The results supported the hypothesized model: the age of the child, the maternal perception of social danger, and positive potentiality of outdoor autonomy were the most influential variables on children's independent mobility, measured as an index. Further, the maternal perceptions mediated the influence of the other demographic, psychosocial, and environmental variables on independent mobility.     

Space-Time Synergetics in Innovation Diffusion: A Nested Network Simulation Approach

The relevance of evolutionary dynamics theories for investigating the development of sociotechnical systems has recently been recognized. In this framework the logistic growth model is considered by many scientists as an extremely appropriate framework that is able to interpret the dynamics of innovation diffusion. Starting from recent results in the literature on technological dynamics, the present paper focuses on backgrounds leading to different shapes of the conventional logistic function. By embedding these motives in the socio-attitudinal context of the system at hand, the present paper tries to give a new interpretation for the rapid/slow “take off” and dynamics of a given innovation in a spatial setting. In particular, a nested logistic dynamic model is developed here, with particular emphasis on the dynamic growth rate of the logistic function expressing—by means of an accessibility cost function—the preference intensity concerning a given innovation for a certain region/country. Finally, various simulation experiments are carried out for the case of both a two-dimensional and a four-dimensional network. The possibility of both stable and unstable diffusion patterns, depending on the parameter values in the nested “attitudinal” dynamic function, is also investigated.     

Laughter and Truth in Fiji: What We May Learn from a Joke

This paper examines a series of events which took place in a Fijian village in the late 1980s and which, for the ethnographer, brought into question joking, lying and telling the truth. The analysis suggests that our ideas of what language is good for necessarily inform our understanding of the truth conditions of what is said, from which it follows that truth may be regarded not as an absolute, but as a function of the moral force of language — itself an historical phenomenon that is embedded in, and constituted through, the everyday social relations that we may analyse in terms of gender, kinship, chiefship, and ideas of the person. Laughter emerges as central both to the events described and their analysis. Subtle though they may be, people's ideas of the moral force of language are amenable to investigation and analysis; but for all we may learn from laughter, it ultimately eludes any analysis — an observation that provides the key to its revelatory force.     

A Mathematical Method for Partitioning a Territory

Two regional characteristics—contiguity (connectivity) and compactness—are described mathematically. An integer programming model is constructed to allocate a system of points optimally (in terms of the compactness criterion) to subgroups whose number is not given beforehand. The conditions that each element of the regional breakdown must satisfy are given in the form of linear constraints of the regional population structure.     

A GENERAL FRAMEWORK FOR THE INTEGRATION OF A LAND-USE MODEL WITH A TRANSPORTATION MODEL COMPONENT

Integrated land-use—transportation models are characterized as models in which the redistributive effects of one subsystem upon the other are explicitly defined and incorporated into the model's structure. At the core of integrated models is a linking procedure whose function is to transform the outputs of one model component into inputs for the other. Despite major efforts made in the past to build operational large scale integrated models, the structural properties of such models remain largely unexplored. This paper describes a general framework for an integrated model consisting of prototype model components. These are an iterative activity allocation model of the Garin-Lowry type, an equilibrium-assignment transportation network model, and a linking procedure. Given the level of analysis, this framework is shown useful for exploring the analytics of integrated models and, in particular, their equilibrium properties. By means of many simulation experiments based on an hypothetical numerical example, the operation of the model is demonstrated with an emphasis on the locational interpretation of the integration procedure. On the basis of the empirical results and considering the model's intrinsic assumptions, the following major findings can be cited. First, the effects of nontravel factors (such as basic employment and zonal attractions) upon activity distribution are stronger than effects caused by changes in the transportation system. The latter effects were found to yield nonlinear and, spatially, nonuniform changes in activity location which also tended to be larger in peripheral regions. Second, implicit in the specification of the integration procedure are behavioral assumptions regarding time-lags in locational adjustments made by activities in reaction to rising cost of travel. The present formulation implies that once located, activities do not revise their locational decisions despite substantial increases in travel costs. At the other extreme, all activities are permitted to readjust their locational preferences after the final interzonal travel costs are derived. The effect upon activity distribution of the latter specification is, of course, larger than that of the former, although less than the effect yielded by changes in nontravel factors. Regarding the equilibrium properties of the integrated system, both the theoretical and empirical analyses show that the entire model will converge into an equilibrium solution and that the corresponding trip patterns are also at equilibrium. These results will hold as long as the operation of the integrated models is completely controlled by the generation functions of the land-use model and the transportation model component only affects the spatial distribution of activities. Finally, the results from the simulation experiments indicate that the computed mean travel cost parameter tends to stabilize around a certain value as the level of demand for travel, within the system, rises. There is evidence that compensating changes in the location and composition of this demand are the main causes of this phenomenon. In light of these findings, it is possible to point to three key problems whose resolution could largely improve the predictive power of integrated models. First, it would be useful to define activity models in which the generation of activities is, among other things, a function of travel conditions. Second, currently formulated integrated models do not contain trip demand functions and, thus, demand for travel by an activity unit is regarded as completely inelastic. Third, different locating activities respond differently—over time and space—to changíng travel conditions, and models should, therefore, reflect explicitly such differences in activity behavior. A recent paper by Los [14], is an important contribution to the analysis of this issue.     

Another Look at Lerna: An EH IIB Trading Post?

The Early Helladic IIB sealings from Lerna have rarely been considered as functional documents even though they are often called as evidence for EH II economic complexity, for elite control of resources or even for ‘central place’ redistribution. Close analysis of the sealings, however, casts doubt on whether the documents support these economic or social interpretations, seeming rather to point to the grafting of a foreign system of resource management onto a less developed society. After examining the specific functions of the sealings —‘who did what?’— we consider their implications for social organization. This evidence is then linked to the wider picture: a whole range of new sealing practices as well as the striking innovations in architecture and construction which appear at much the same time. We conclude that these developments are largely due to the arrival of foreign (probably Anatolian) traders at Lerna early in EH IIB.     

省域城市网络中心性测度及比较研究——以江苏省和广东省的对比分析为例

城市网络中心性是衡量城市地位、分析城市体系的重要概念.本文在剖析中心性理论内涵的演化后,提出网络中心性应当同时体现规模等级和要素流动的水平.通过区分静态网络和联系网络,论文构建了基于规模数据和流动数据的网络中心性评价体系,并以江苏、广东为例进行实证分析.研究发现:①从规模和联系两类城市网络中心性的视角识别首位城市是有效...     

Latino immigrants and the renegotiation of place and belonging in small town America

This article compares the politics of place and belonging within two non-metropolitan communities—Woodburn, Oregon, and Leadville, Colorado—that have witnessed a significant increase in Latino immigration during the last fifteen to twenty years. Today both communities are approximately 50 per cent Latino, a demographic change that has reworked understandings of place identity and social belonging in each. Through a comparison of the two towns we seek to chart the unique regional political economic dynamics driving these changes, examine their spatial imprint, and interrogate how local context shapes the extent to which new arrivals are able to make effective claims to a sense of place and belonging despite hierarchies of race, class and ‘illegality.’ Assessing the differences between these two immigrant destinations provides insights into how sociospatial relations are crucial to analyzing immigrant–receiving society interaction, and contributes to scholarship on the uneven geography of immigrant incorporation in the contemporary USA.     

Social Identity and Ethnic Interaction in the Western Pueblos of the American Southwest

With the increasing realization of the frequency of migration in prestratified societies, our understanding of ethnic interaction needs to become more sophisticated. This paper discusses ethnic interaction in prestratified societies on a theoretical level by examining currently used models based on Barth's concepts of interaction (Barth, F., Ethnic Groups and Boundaries, Little, Brown, Boston, 1969, pp. 9–39) and Bourdieu's concept of habitus (Bourdieu, P., Outline of a Theory of Practice, Cambridge University Press, Cambridge, 1977). These current models are flawed, and an alternative model relying on reflexive decisions by agents who are constrained by their place within the existing social structure is presented. This model is then used to examine ethnic identity in Western Pueblo societies in three areas of central Arizona: Point of Pines, Grasshopper, and Silver Creek. All three areas were locations of prehistoric migration and subsequent interaction between migrants and indigenous peoples. However, the nature of the interaction differed considerably, with ethnicity being emphasized in some places, de-emphasized in others, and ignored all together in still others.     

中心地体系中的分形和分维

中心地体系中蕴含着分形结构,具有多分维特征。本文借助koch雪花和随机Sierpinski图形揭示了中心地k=3体系和k=4体系的生成机制,提出了城乡聚落体系和城市-交通网络的两种分形模型,这些模型的分维与S.Arlinghaus的发现具有对应性。     

基于系统动力学的我国旅游景区门票定价研究

已有景区门票定价研究大都从现实景区数据出发,建立门票价格、景区属性和社会经济指标的多元回归模型。然而这种计量研究,并没有从景区门票定价的多目标性出发,也忽视了影响门票定价各因素之间的相互影响关系。本文构建ISM模型分析影响景区门票定价的主要因素及其相互关系,根据因素相互作用关系建立景区门票定价系统因果关系图和系统流图,并设定系统动力学方程。仿真结果显示,成本票价逐年下降并于2022年降至最低,而最终票价将呈现先降低后升高的趋势。