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.     

IBEM for Impedance Functions of an Embedded Strip Foundation in a Multi-Layered Transversely Isotropic Half-Space

An indirect boundary element method (IBEM) is developed to study the dynamic impedance functions (stiffness coefficients) of a rigid strip foundation embedded in a multi-layered viscoelastic transversely isotropic (TI) half-space. The proposed IBEM using half-space Green’s functions of distributed loads as fundamental solutions have the merits of fictitious loads being directly applied on the real boundaries without the problem of singularity and of the discretization effort restricted to local boundaries. In addition, the accuracy of the proposed method is not affected by the thickness of the discrete TI layers, as the exact dynamic stiffness matrix is employed. The presented algorithm is verified via comparisons with published results for the isotropic medium. By taking a rigid strip foundation embedded in a homogeneous half-space, a single-layered half-space, and a multi-layered half-space as examples, the effects of material anisotropy, frequency of excitation, and soil layer on the impedance functions are studied in detail. Numerical results show that impedance functions for the TI medium can be significantly different from those of the isotropic case. The variation of TI parameters alters the dynamic characteristics of the TI layered site, which in turn alters the dynamic interaction between the soil and foundation. In addition, the soil sedimentary sequence also has a remarkable influence on the impedance functions.     

Dynamic Interaction between Rigid Foundations on Multi-layered Stratum

This article concerns the cross-interaction problem among multi-foundations on a linearly viscoelastic medium at very small shear strains. In the analysis, the foundations are discretized into a number of sub square-elements. The dynamic response within each sub-element is described by the Green’s function, which is obtained by the Fourier-Bessel transform and the precise integration method. Incorporating the displacement boundary condition and the force equilibrium of the foundations, it obtains the dynamic impedance and compliance functions of the foundations. Extensive results for two rigid circular foundations placed at different separations are presented. Parametric studies are carried out on the dynamic interaction among adjacent foundations. Illustrative results for several closely spaced foundations are also illustrated.     

A REGIONAL ECONOMY,LAND USE,AND TRANSPORTATION MODEL (RELU‐TRAN©): FORMULATION,ALGORITHM DESIGN,AND TESTING*

ABSTRACT RELU is a dynamic general equilibrium model of a metropolitan economy and its land use, derived by unifying in a theoretically valid way, models developed by one of the authors [ Anas (1982) , Anas–Arnott (1991, 1997) , Anas–Kim (1996) , Anas–Xu (1999) ]. RELU equilibrates floor space, land and labor markets, and the market for the products of industries, treating development (construction and demolition), spatial interindustry linkages, commuting, and discretionary travel. Mode choices and equilibrium congestion on the highway network are treated by unifying RELU with the TRAN algorithm of stochastic user equilibrium [ Anas–Kim (1990) ]. The RELU‐TRAN algorithm's performance for a stationary state is demonstrated for a prototype consisting of 4‐building, 4‐industry, 4‐labor‐type, 15‐land‐use‐zone, 68‐link‐highway‐network version of the Chicago MSA. The algorithm solves 656 equations in a special block‐recursive convergent procedure by iterations nested within loops and loops within cycles. Runs show excellent and smooth convergence from different starting points, so that the number of loops within successive cycles continually decreases. The tests also imply a numerically ascertained unique stationary equilibrium solution of the unified model for the calibrated parameters.     

Building Communities in Ancient Samnium: Cult,Ethnicity and Nested Identities

This article addresses the meaning of community in an area of the ancient world that is normally seen to diverge from the paradigm of the Classical city‐state, by examining the role of sanctuaries in the articulation of identity and belonging. The focus is on Samnium (central Italy) in the last four centuries BC, where archaeological and historical evidence, including a wealth of recent discoveries, supports a dynamic view of a region that is traditionally associated with a cohesive ethnic group. Whilst it is true that the major sanctuary at Pietrabbondante fostered the construction of Samnite ethnic identity, this article highlights the importance of other types and levels of belonging in light of a broader range of cult sites. The concept of ‘nested identities’ (a scenario where individuals identify simultaneously with overlapping groups) can bring about a more nuanced view of how cult was used as a means to negotiate belonging on ethnic and non‐ethnic levels. I hope to show that local communities, and particularly the local elites, were able to function independently rather than simply as the building blocks of the Samnite ethnos.     

PANEL DATA MODELS WITH SPATIALLY DEPENDENT NESTED RANDOM EFFECTS

This paper focuses on panel data models combining spatial dependence with a nested (hierarchical) structure. We use a generalized moments estimator to estimate the spatial autoregressive parameter and the variance components of the disturbance process. A spatial counterpart of the Cochrane‐Orcutt transformation leads to a feasible generalized least squares procedure to estimate the regression parameters. Monte Carlo simulations show that our estimators perform well in terms of root mean square error compared to the maximum likelihood estimator. The approach is applied to English house price data for districts nested within counties.     

Rocking of Non-symmetric Rigid Blocks in Buildings Considering Effects Associated with Dynamic Soil-Structure Interaction

A dynamic model for the estimation of the rocking and/or overturning response of a free-standing non-symmetric rigid block considering rotational and horizontal excitation is proposed. The block is situated at different levels of a building with flexible base subjected to earthquakes. Base flexibility introduces the rotational component of the excitation due to dynamic soil-structure interaction (DSSI). The model is used to assess the influence of the dynamic soil-structure interaction on the behavior of the block. An illustrative example of the proposed model for non-symmetric rigid blocks in 5-, 10-, and 15-story buildings located in soft soils considering earthquakes from different seismic sources is presented. Results show that it is important to consider kinematic effects as well as inertial effects of DSSI in the dynamic response of contents. The influence of base flexibility depends on the change of spectral intensities associated to the increase of the building structural period and is larger for higher building levels.     

Multiple Contexts as Cross-classified Models: The Labor Vote in the British General Election of 1992

Voters make their decisions in social and geographical contexts that can be seen as different levels in an overall data structure. Increasingly these structures are being analyzed by multilevel models, but this approach has so far been limited to structures that are strictly hierarchical. This paper outlines the approach of cross-classified multilevel models in which units at lower levels in the structure can be nested in more than one higher-level unit simultaneously. An appropriate modeling framework is outlined, models are specified, and particular attention is paid to efficient computation. The approach is illustrated through a cross-classified logit analysis of Labor versus Conservative support for a nationally representative sample of voting behavior for the 1992 British General Election. The data is structured so that individual voters at level 1 are nested within constituencies at level 2 which are cross-classified by geographical and functional regionalizations at level 3. A conclusion discusses the general utility of a cross-classified approach to geographically based contextual research, while two technical appendices provide details on model estimation.     

DISCRETE SPATIAL CHOICE MODELS FOR AGGREGATE DESTINATIONS*

ABSTRACT. In problems of spatial choice, the choice set is typically more aggregated than the one considered by decision-makers, often because choice data are available only at the aggregate level. These aggregate choice units will exhibit heterogeneity in utility and in size. To be consistent with utility maximization, a choice model must estimate choice probabilities on the basis of the maximum utility within heterogeneous aggregates. The ordinary multinomial logit model applied to aggregate choice units fails this criterion as it is estimated on the basis of average utility. In this paper, we derive and discuss a model which utilizes the theory underlying the nested logit model to estimate the appropriate maximum utilities of aggregates. We also demonstrate that the aggregate alternative error terms are asymptotically Gumbel, thereby relaxing the assumption of extreme value distributed error terms. This is accomplished with help from the asymptotic theory of extremes.     

Stone circles and the structure of Bronze Age society

Analyses of modern human societies have consistently demonstrated the presence of recurrent grouping levels forming a nested, hierarchical structure. That this structure exists in both hunter-gatherer and western industrialized societies suggests that it may be a fundamental organizing principle of considerable antiquity. Stone circles are perceived as being foci of aggregation for prehistoric groups and thus provide a proxy for the sizes of those aggregations. Combining an empirical analysis of a sample of 140 stone circles with a Monte Carlo simulation model that derives expectations for a continuous size distribution based on the nested hierarchy concept, the current paper suggests that similar organizing principles were already in place during the Bronze Age. Furthermore, it is suggested that findings traditionally attributed to the operation of the ‘rank-size rule’ may in fact reflect the basic underlying structure of human society.     

SHAKING TABLE DYNAMICS: RESULTS FROM A TEST-ANALYSIS COMPARISON STUDY

This paper presents the results of a comprehensive comparison study between the analytically predicted and experimentally identified dynamics of the shaking table system built recently in the Structural Engineering Laboratory at Rice University in Houston, Texas. The primary objectives of the research presented here are two-fold: (1) to shed light into the dynamic performance of asmall-tc-medium size, uni-axial, servo-hydraulic, displacement-controlled shaking table system, and (2) to validate a linearised dynamic model of the system (in the form of the total shaking table transfer function) developed earlier by the authors from basic principles. The analytical model incorporates the inherent dynamic characteristics of the various components of the shaking table system (i.e. controller, servovalve, actuator, test specimen, and reaction mass) and their dynamic interaction.

The test-analysis correlation study performed over a wide range of operating and payload conditions provides useful information on the sensitivity of the shaking table transfer function to control gain parameters and how it can be used to tune the shaking table controller for optimum performance under various payload conditions. The good test-analysis correlation results obtained validate the analytical shaking table model, show its robustness, and provide keen insight into the underlying coupled dynamics of a shaking table system. In order to achieve this good test-analysis correlation, it was crucial to include a time delay in the analytical model of the shaking table system (innovative feature of the model to account for the time lag in the response of the servovalve-actuator system). The expected significant dynamic interaction between payload and shaking table is also confirmed by this study.     

Rethinking Soft Power in the Post‐Blockade Times: The Case of Qatar

This study seeks to advance the understanding of the utility of “soft power” by exploring the case of Qatar. The country's approach is conceptualized as “nested power” through the examination of its political strategies before and after the regional blockade in 2017. The role of soft and nested power in Qatar has already been examined through various vantage points, such as small state diplomacy, mediation, and sports. Since the blockade has been for Qatar a great strategic dilemma, examination of how it affected power dynamics reveals the salience as well as the resilience of Qatar's soft and nested power. The article will discuss the concepts of “soft” and “nested” powers and their relevance to the state of Qatar in general and it will focus in the final section on the post‐blockade period. In doing so, we also seek useful approaches, which can be compatible with, and even advance “global international relations” (IR). The movement to make IR more global and inclusive is a welcome feature of the current century, reflective of the burgeoning role of the “Global South.”     

Exogenous Workplace Choice in Residential Location Models: Is the Assumption Valid?

This paper examines the assumption implicit in most models of residential location that the choice of workplace is exogenously determined. Monocentric models have generally made this assumption, but it has come under increasing scrutiny. A nested logit model of workers' choices of workplace, residence, and housing tenure within the Dallas-Fort Worth metropolitan area is developed to provide a test. A unique dataset that includes the workplace and residence census tracts of workers in Dallas-Fort Worth, and their demographic and socioeconomic characteristics, is used to estimate the model. The results confirm that a joint choice specification better represents actual choice behavior in a multinodal metropolis.     

Land Use Patterns in Central Asia. Step 1: The Musical Chairs Model

Herding and farming coexisted in Central Asia for several thousand years as main options of preindustrial economic production. The relationship between people practicing different variants of these modes of subsistence is known to have been dynamic. Among the many possible explanations, we explore this dynamic by modeling mechanisms that connect aggregate decisions to land use patterns. Within the framework of the SimulPast project, we show here the results from step 1 of our modeling program: the Musical Chairs Model. This abstract agent-based model describes a mechanism of competition for land use between farming and herding. The aim is the exploration of how mobility, intensity, and interdependence of activities can influence land use pattern. After performing a set of experiments within the framework of this model, we compare the implications of each condition for the corroboration of specific land use patterns. Some historical and archaeological implications are also discussed. We suggest that the overall extension of farming in oases can be explained by the competition for land use between farming and herding, assuming that it develops with little or no interference of climatic, geographical, and historical contingencies.     

SYSTEM IDENTIFICATION OF LANDFILL SEISMIC RESPONSE

Assessment of landfill seismic response necessitates the availability of reliable dynamic material properties. During the past decade, geophysical surveys and computational studies have been conducted to investigate the seismic response of the Operating Industries, Inc. (OII) landfill in Southern California. In this paper, a survey and summary of available research results is presented. In addition, a set of Oil input-output seismic records during six earthquakes is thoroughly analysed. Spectral analyses are conducted to shed light on the landfill dynamic response characteristics. A simple shear beam model is found to be useful in modelling the landfill resonant behaviour. System identification techniques are employed to estimate the landfill stiffness and damping properties. These properties are defined by minimising the difference between computed and recorded acceleration response spectra at the landfill top. The identified stiffness properties are found to be near the lower bound of those documented through geophysical measure-ments. Identified damping of about 5% (at resonance) is within the range of earlier investigations. Comparisons of the computed and recorded accelerations show: (I) effectiveness of a linear viscous shear beam model in simulating the landfill dynamic behaviour, for the recorded small to moderate levels of dynamic excitation (up to 0.26 g peak lateral acceleration), and (ii) potential of the employed system identification procedure for analysis of input-output seismic motions.     

Dynamic Central Place Theory: Results of a Simulation Approach

A dynamic central place theory is formulated as a simulation model in which retail activities, described by cost equations, and consumers, described by spatial interaction equations, interact to generate a central place system. The behavior of the model is then examined. Simulation results show that the basic character of the system—whether it is agglomerated or dispersed—depends primarily on a single parameter in the interaction equation, and only secondarily on the specification of the cost function. The results are highly robust in that they are largely independent of the initial sizes and locations of centers, and even independent of the type of interaction equation used. The patterns generated appear plausible.     

Alternative Nested Logit Model Structures and the Special Case of Partial Degeneracy

Partially degenerate nested logit (NL) models have broad applicability in regional science. However, the literature on them is relatively sparse and confusion exists on some aspects of identification and related matters. This paper addresses a number of conceptual and econometric aspects of partially degenerate NL models. These include identification, scaling, invariance, and consistency with the utility-maximizing postulate that underlies discrete choiceanalysis. This is accomplished within the larger, encompassing framework of nondegenerate NL models of which the partially degenerate model is a special case.     

The segregation of generations: ancestral groups in Sydney, 2011

Most models of immigrant minority enclave formation in cities represent their situation as relatively transient elements in urban residential mosaics. As minority group members become both economically integrated and socially–culturally assimilated into the host society, so they move away from the enclaves where they initially concentrated. Such shifts are especially likely in the second and later generations of group members, who are more likely to overcome the disadvantages experienced by many of the original settlers with regard to human capital. This paper evaluates that model using data on the residential distributions of three generations of those claiming one of 19 different ancestral groups in Sydney in 2011, at four nested spatial scales, deploying a recently developed inferential method for evaluating the intensity of residential segregation. The findings are not consistent with the model: in general, members of the second and third generations in any ancestral group are as segregated as the first generation (that is, those born outside Australia) at both regional and neighbourhood scales.     

基于动态实时调度的主题公园游客时空分流导航管理研究

本文针对主题公园游客时空分流导航问题进行了研究,提出了一种与现实情形极为吻合的最小代价实时策略,借此构建了面向景点负荷均衡的游客导航分流模型,并用实验模拟了整个动态调度过程。实验结果表明,该导航模型能有效地引导游客前往等候时间最短的景点,很好地解决在各景点上负载不均的问题。通过在时间和空间上的科学的分流设计,既能提高游客的满意度,又便于景区人员随时掌握景区内资源的使用情况,提高景区常态化管理的质量,从而加速旅游、经济和生态的可持续发展。     

Joint Effects of Personal Factors and Ecological Variables on the Interprovincial Migration Pattern of Young Adults in Canada: A Nested Logit Analysis

This paper applies a nested logit model to the 1981 census micro data to study the joint effects of personal factors (sex, mother tongue, nativity, education, and marital status) and ecological variables on the 1976–1981 interprovincial migration pattern of young adults in Canada. In multivariate contexts, personal factors not only are of paramount importance in explaining the departure process but also have significant interactions with ecological variables in determining the destination choice pattern.