Establishment of a Time-Varying Modified Kanai-Tajimi Non Stationary Stochastic Model of Seismic Records Based on the S-transform

This article investigates the time-varying characteristics of seismic records. Time-varying amplitude and energy spectrums are defined to reflect the time-frequency dependence, and a general formulation of the S-transform is introduced. The S-transform is tested with various window functions to analyse the Kobe seismic records. The results indicate that using a complex window function with properly adjusted parameters gives favorable outcomes. Analyses of three soil sites show that sites with hard soil feature seismic records with shorter stationary durations, higher frequency centers, and broader frequency bands than other soil sites. The average time-varying spectrums of the seismic records are simulated using a uniform non stationary stochastic model and a time-varying modified non stationary Kanai-Tajimi stochastic model. Empirical formulas are established for the time-varying spectrums of the earthquake records from these sites by nonlinearly fitting stochastic models to the record data. The values of the time-varying spectrum factors for different earthquake intensities and sites agreeing with the Chinese Seismic Code are obtained. Based on these analyses and observations, we propose using the solutions to the stochastic models to simulate non stationary ground motions.     

A Ground Motion Record Selection Approach Based on Multiobjective Optimization

The evaluation of the seismic safety and reliability of buildings and building contents within a probabilistic framework often requires response history analyses using site-specific ground motion records. The ground motion selection method proposed in this paper addresses this issue by a stochastic search procedure in which record sets are selected such that first- and second-order statistics (median and dispersion) satisfy predefined ground motion spectrum targets over a wide period range. Once a ground motion record set is selected, it can be used for seismic assessment of a broad class of buildings within the target period range at the given location.     

FUZZY PATTERN CLASSIFICATION OF STRONG GROUND MOTION RECORDS

Classification of earthquake strong ground motion (SGM) records is performed using fuzzy pattern recognition to exploit knowledge in the data that is utilised in a genetic algorithm (GA) search and scaling program. SGM records are historically treated as “fingerprints” of certain event magnitude and mechanism of faulting systems recorded at different distances on different soil types. Therefore, databases of SGM records of today present data of complex nature in high dimensions (many of the dimensions—or SGM parameters in time and frequency domain—are presently available from different archives). In this study, simple ground motion parameters were used but were combined and scaled nonlinearly such that the physical properties of the data could be preserved while reducing its dimensionality. The processed data was then analysed using fuzzy c-means (FCM) clustering method to explore the possibility of meaningfully representing earthquake SGM data in lower dimensions through finding subsets of mathematically similar vectors in a benchmark database. This representation can be used in practical applications and has a direct influence on the processes of synthesising ground motion records, identifying unknown ground motion parameters (e.g. soil type in this study), improving the quality of matching SGM records to design target spectra, and in rule generalisation for response. The results showed that the stochastic behaviour of earthquake ground motion records can be accurately simplified by having only a few of motion parameters. The very same parameters may also be utilised to derive unknown characteristics of the motion when the classification task on “training” records is performed carefully. The clusters are valid and stable in time and frequency domain and are meaningful even with respect to seismological features that were not included in the classification task.     

Ductility-Equivalent Viscous Damping Relationships for Beam-to-Column Partial-Strength Steel Joints

This paper seeks to contribute to the development and improvement of displacement-based design procedures, proposing improved ductility-equivalent viscous damping relationships for steel moment-resisting framed structures with dissipative beam-to-column partial-strength joints. These relationships can be used directly in procedures like the Direct Displacement-Based Seismic Design (DDBD) that uses effective stiffness, ductility-equivalent viscous damping relationships, and period-displacement relationships in a performance-based design approach. To this end, a finite element model of a steel beam-to-column sub-assemblage, characterized by an extended end-plate, is developed in ABAQUS. The model, which is validated against monotonic and cyclic experimental data obtained in previous research, is employed to carry out non-linear time-history (NLTH) analyses, using real records scaled to target several levels of ductility demand. A procedure is then proposed and applied to determine the ductility-equivalent viscous damping relationships of the sub-assemblages. The equivalent linearization technique is applied to the non-linear responses obtained in the NLTH analyses, using an elastic single degree of freedom structure and the elastic displacement spectra. The influence of joints mechanisms and of the dynamic characteristics of the structure in the equivalent viscous damping is investigated, and an expression for ductility-equivalent viscous damping is proposed. The proposed expression represents a clear improvement in relation to the existing expressions available in literature.     

Long-Period Ground Motion Simulation and its Impact on Seismic Response of High-Rise Buildings

This paper first critically reviews a seismological model and then a three-segment curve model (in log-log space) to model the Q-f relationship is proposed to overcome the potential biased estimation in the long-period range by the “coda wave” method. The optimal curve-fitting process is performed to determine the Q-f relationship for the Hong Kong region. The calibrated seismological factors are incorporated with the stochastic simulation procedure to generate synthetic ground motions, which are validated through comparison with seismic records. The impact of long-period ground motions on the seismic response of high-rise buildings is finally manifested through a numerical study.     

Detecting the effects of selection and stochastic forces in archaeological assemblages

Detecting and diagnosing the causes of change through time in archaeological assemblages is a core enterprise of archaeology. Evolutionary approaches to this problem typically cast the causes of culture change as being either stochastic in origin, or arising from selection. Stochastic sources of change include random innovations, copying errors, drift and founder effects among dispersing groups. Selection is driven by differences in payoffs between cultural variants. Most efforts to identify these evolutionary forces in the archaeological record have relied on assessing how well the predictions from a neutral-stochastic model of cultural transmission fit a data set. Selection is inferred when the neutral-stochastic model fits poorly. A problem with this approach is that it does not test directly for the presence selection. Moreover, it does not account for the fact that both neutral-stochastic and selective forces can act at the same time on the same cultural variants. A different approach based on the Price Equation allows for the simultaneous measurement of selective and stochastic forces. This paper extends use of the Price Equation to the analysis of selective and stochastic forces operating on multiple artifact types within an assemblage. Ceramic data presented by Steele et al. (2010, Vol. 37(6): 1348–1358) from the Late Bronze Age Hittite site of Bo?azköy-Hattusa, Turkey, provide an opportunity to evaluate the efficacy of this model. The results suggest that selection is a dominant process driving the frequency evolution of different bowl rim types within the assemblage and that stochastic forces played little or no role. It is also clear, however, that we should be attentive to combinations of direct and indirect selective effects within assemblages consisting of multiple artifact types.     

第二轮志书应当写好改革篇——以《修文县志（1978～2008）》为例

方志界对志书如何更好地记述改革有三种观点：集中记述、分散记述、集中与分散相结合记述。文章以《修文县志（1978～2008）》为例,主张采用政治部类集中,经济、文化部类分散的方式记述改革。同时,记述改革要在篇目上体现时代特色;充分占有反映改革内容的资料,深入基层收集鲜活的资料;要以精炼的文笔、时代的语言完整地记述改革。     

Forecasting in a Small and Unstable Regional Economy Using Regime Shifting Models: The Case of Extremadura

We consider forecasting in a small and unstable regional economy subject to structural breaks. In this context, we work with two types of regime‐shifting databased models using cointegration theory. The objective of the present work is to analyze the out‐of‐sample forecasting performance of the two approaches used to construct a short‐term regional econometric model: stochastic and deterministic time varying parameters models. The forecasting experiments will be illustrated by specifying, and estimating an econometric model for Extremadura, a small and unstable region in southwestern Spain.     

Insane Innocents: Mad Children in Benedict of Peterborough’S Miracula Sancti Thomae Cantuariensis 1

Abstract

This article discusses the setting up and operation of the Kingston Local History Project, emphasizing, in this process, the active co-operation between Kingston University and the local community. The Project aims to construct a comprehensive database on the people of Kingston between I850 and I900 and to subject the data collected to rigorous analysis. This will provide an extensive longitudinal socio-economic profile of an important market town in transition and, via techniques of record linkage, details of the life-cycles of thousands of Kingstonians. The core of the database is the decennial census enumerators’ books I85I-I89I, plus details from other sources, including parish registers and cemetery records. Data on female domestic service are then analysed to demonstrate how the database enables some important research questions to be tackled.     

Sequential, Bayesian Geostatistics: A Principled Method for Large Data Sets

The principled statistical application of Gaussian random field models used in geostatistics has historically been limited to data sets of a small size. This limitation is imposed by the requirement to store and invert the covariance matrix of all the samples to obtain a predictive distribution at unsampled locations, or to use likelihood-based covariance estimation. Various ad hoc approaches to solve this problem have been adopted, such as selecting a neighborhood region and/or a small number of observations to use in the kriging process, but these have no sound theoretical basis and it is unclear what information is being lost. In this article, we present a Bayesian method for estimating the posterior mean and covariance structures of a Gaussian random field using a sequential estimation algorithm. By imposing sparsity in a well-defined framework, the algorithm retains a subset of " basis vectors " that best represent the " true " posterior Gaussian random field model in the relative entropy sense. This allows a principled treatment of Gaussian random field models on very large data sets. The method is particularly appropriate when the Gaussian random field model is regarded as a latent variable model, which may be nonlinearly related to the observations. We show the application of the sequential, sparse Bayesian estimation in Gaussian random field models and discuss its merits and drawbacks.     

Seismic Response of Bridges Subjected to Different Earthquake Types Using IDA

Incremental Dynamic Analysis (IDA) was used to evaluate the seismic response of straight, continuous 4-span bridges with different sub-structure configurations. Three different record sets were chosen to represent three different earthquake types which can occur for a site such as Vancouver (i.e., crustal, subduction interface, and subduction inslab earthquakes). Seventy eight records were considered in each set (i.e., a total of 234 records) and the capacities of the bridges were evaluated using a fast IDA algorithm. A simplified method to account for the effects of spectral shapes was used. Different subsets of the records with specific characteristics were also used in the IDA. The bridges were designed and evaluated for two different design force modification factors and bridges with different degrees of irregularity were studied. Comparisons of the IDA results obtained indicated that in most of the cases the interface record sets resulted in lower median collapse capacities and hence were the most critical of the ground motions studied.     

Nonlinear Structural Response to Low-Cut Filtered Ground Acceleration Records

Ground acceleration records obtained from instruments in the field are often filtered to reduce noise in both low and high frequency bands before being used for structural response analyses. The structural analysis using a filtered acceleration record may elongate the fundamental period of a structure which will potentially lead to an underestimation of the nonlinear response.

The nonlinear response of single-degree-of-freedom systems to low-cut filtered ground acceleration records is investigated. Based on the results of this study, a simple criterion for selecting ground acceleration records for seismic response analyses is proposed to avoid underestimating the nonlinear structural response.     

Simulating global patterns of Pleistocene hominin morphology

The first ever simulations of global patterns of early Homo morphology are presented here. These simulations are a good match to the known patterns in the fossil record. An enhanced version of the Stepping Out model is presented which simulated global patterns of hominin morphology including genetic drift and the homogenising effects of inter-group exchange. Stepping Out is then used to examine the importance of environmental factors on hominin morphology. The most significant feature of the simulations is an emergent division between the African and Asian populations. The effect of biogeographical factors on this division and other patterning is considered. Throughout, modelling results are interpreted in the context of fossil and archaeological records in order to enhance our understanding of population histories of hominin groups.     

Combining Indigenous and Maritime Archaeological Approaches: Experiences and Insights from the ‘(Re)locating Narrunga Project’, Yorke Peninsula, South Australia

This paper details the unique pairing of Indigenous and maritime archaeological approaches in the ‘(Re)locating Narrunga Project’. Narrunga was a ketch built by the Narungga Aboriginal community at Point Pearce Mission (Yorke Peninsula, South Australia) at the turn of the twentieth century and later sunk in the 1940s. It is argued that convergences between the scholarly interests of Indigenous and maritime archaeological approaches have been slow to develop and that maritime archaeology as a sub-discipline has not capitalized on the insights that can be gained from collaborative approaches between communities and practitioners. Similarly, Indigenous communities in Australia have had few opportunities to work with researchers to record their maritime heritage. As is evident in the Narrunga story told in this research, non-Indigenous records have been complicit in underplaying the maritime achievements and skills of Narungga people and collaborative research can work towards decolonizing this past.     

Paleotemperature record in late pleistocene clastic sediments at Divje babe 1 cave (Slovenia)

A new sedimentary morphogenic analysis was carried out at the Divje babe I Paleolithic site to determine paleotemperatures for Late Pleistocene deposits (around 80,000–40,000 BP) and to discover hiatuses in the sedimentary sequence. The Divje babe I paleotemperature record is based on the relative abundance of congelifracts in a 280 cm thick sedimentary sequence. Congelifracts are clasts whose morphogenesis is directly associated with post-depositional frost wedging. The Divje babe I paleotemperature record compares well with global GRIP (Summit) and other regional paleotemperature records for the Late Pleistocene. Comparisons are supported by ESR dates from the Divje babe I site. Two significantly cool climate phases were identified in the Divje babe I record. The older cool phase was placed between 67,000 BP and 62,000 BP and the second, younger cool phase was placed between 61,000 BP and 58,000 BP (both Middle Würmian) according to correlations with the GRIP record. The main disadvantage with the Divje babe I paleotemperature record is missing data. The sequence of cave sediments is not complete in Divje babe I due to breaks in sedimentation. Two reliable and two assumed hiatuses were identified in the studied sedimentary sequence.     

The State,Convicts and Longitudinal Analysis

In 2006 the Records of the Tasmanian Convict Department were inscribed on the UNESCO Memory of the World Register. This extraordinarily intact collection of records document the lives of 73,000 male and female prisoners transported to Van Diemen’s Land. This article examines ways in which this information can be used to explore the impact of forced labour migration on the lives of convicts. It focuses in particular on the assembly of cradle-to-grave datasets. Such longitudinal approaches to the past can be powerful, especially where they involve the analysis of multiple life course events for a large number of individuals. The first part of the article explores ways in which quantitative approaches can be used to reconstruct the circumstances that shaped the creation of record groups. The second part examines the way in which longitudinal analysis can be used to analyse the impact of state action on the lives of convicts.     

A dynamic model of interregional migration flows in Great Britain

"The purpose of this study is to construct a dynamic model of migration in Great Britain based on time-series data developed from the records of the National Health Service Center Register (NHSCR) on male migrants of working age between 1975 quarter 2 and 1979 quarter 2." A two-stage methodology "was developed...which differed in many important respects from the techniques adopted in previous studies of time-series migration flows. Regional push and pull factors were derived on the basis of the revealed preferences of migrants, using a two-stream gravity model, and then subsequently related to vectors of regional characteristics, within a general dynamic setting. Factors affecting the overall volume of migration nationally were separated out from those determining the internal direction of migration flows, and factors affecting distance sensitivity. Despite weaknesses in the available data set, the results achieved...suggested many interesting dynamic responses, implying lengthy and important lags in the estimated relationships."     

The Australian Summer Monsoon: a Biogeographic Perspective

Knowledge of the climatological processes that drive the Australian summer monsoon and the ecological consequences of this highly predictable seasonal cycle of wet summers and dry winters has greatly increased over the last several decades. Nonetheless, remarkably little is known about the antiquity of this climate system or how the geographic extent and duration of the monsoon have varied across temporal scales from the recent to the distant geological past. Late Pleistocene sedimentary records from lakes in the interior and north of the Australian continent have been used as a measure of the strength of the palaeo–monsoon. However, in the case of the inland lakes this approach is confounded because it is known that under the contemporary climate, full–lake conditions occur infrequently in response to high rainfall following either a strongly positive ENSO phenomenon (la Nina conditions) or following the continental incursion of tropical depressions. While the general absence of sedimentary and fossil records of the early Pleistocene and late Tertiary prevents elucidation of the timing of onset of the summer monsoon, the degree of biological adaptation of a diverse assemblage of organisms to the wet–dry tropical climate suggests that the summer monsoon climate is of great antiquity. This point is substantiated by a brief review of the ecophysiology of a range of Eucalyptus savanna plant species, the biophysics of the endemic ‘magnetic’ termite mounds and the reproductive cycle of a freshwater turtle. Assuming that the configuration of land and sea is of critical importance in controlling the strength of the Australian summer monsoon, then the notion of great antiquity of the monsoon is also consistent with the fact that for much of the Quaternary, and probably also during the late Tertiary, the relative extent of sea and land has been similar to that of today. The reliable, dry season, southeasterly trade winds create conditions favouring widespread, frequent bushfires. Under both European and Aboriginal management regimes most fires are started by people, although fires can be started by rain–free thunderstorms that occur during the transition between the dry and wet season when intense convection storms are common. Prior to human colonisation such storms would have been an important ignition source for landscape fires, and this may help explain why the north Australian biota is so remarkably tolerant of recurrent fires. The general absence of fossil evidence also frustrates attempts to determine what effect burning by late–Pleistocene human colonisation had on the north Australian landscapes. Given the tolerance of biota to fire, this change may have only affected vegetation structure. Therefore the effect may be very difficult to detect from the pollen record once suitable longer–term records become available. The isotopic signature in extinct and extant ratite eggshells from late Pleistocene sediments in the Lake Eyre basin has been used to infer the destruction of large expanses of woody vegetation by anthropic burning. It has been hypothesised that this changed the hydrological cycle thereby ultimately weakening the continental penetration of the summer monsoon. However, this interpretation is difficult to sustain given the great difficulty in extracting a clear ‘signal’ of an anthropic impact from the inherent variability and fragmentary record of the palaeo–summer monsoon.