Contiguity Constraints for Single‐Region Site Search Problems

This paper proposes an explicit set of constraints as a general approach to the contiguity problem in site search modeling. Site search models address the challenging problem of identifying the best area in a study region for a particular land use, given that there are no candidate sites. Criteria that commonly arise in a search include a site's area, suitability, cost, shape, and proximity to surrounding geographic features. An unsolved problem in this modeling arena is the identification of a general set of mathematical programming constraints that can guarantee a contiguous solution (site) for any 0–1 integer‐programming site search formulation. The constraints proposed herein address this problem, and we evaluate their efficacy and efficiency in the context of a regular and irregular tessellation of geographic space. An especially efficient constraint form is derived from a more general form and similarly evaluated. The results demonstrate that the proposed constraints represent a viable, general approach to the contiguity problem.     

Designs for Detecting Spatial Dependence

The aim of this article is to find optimal or nearly optimal designs for experiments to detect spatial dependence that might be in the data. The questions to be answered are: how to optimally select predictor values to detect the spatial structure (if it is existent) and how to avoid to spuriously detect spatial dependence if there is no such structure. The starting point of this analysis involves two different linear regression models: (1) an ordinary linear regression model with i.i.d. error terms—the nonspatial case and (2) a regression model with a spatially autocorrelated error term, a so-called simultaneous spatial autoregressive error model. The procedure can be divided into two main parts: The first is use of an exchange algorithm to find the optimal design for the respective data collection process; for its evaluation an artificial data set was generated and used. The second is estimation of the parameters of the regression model and calculation of Moran's I , which is used as an indicator for spatial dependence in the data set. The method is illustrated by applying it to a well-known case study in spatial analysis.     

Design Earthquake Ground Motion Prediction for Perth Metropolitan Area with Microtremor Measurements for Site Characterization

Perth is the largest city in Western Australia and home to three-quarters of the state's residents. In recent decades, there have been a lot of earthquake activities just east of Perth in an area known as the South-West Seismic Zone. Previous numerical results of site response analyses based on limited available geology information for PMA indicated that Perth Basin might amplify the bedrock motion by more than 10 times at some frequencies and at some sites. Hence, more detailed studies on site characterization and amplification are necessary. The microtremor method using spatial autocorrelation (SPAC) processing is a useful tool for gaining thickness and shear wave velocity (SWV) of sediments and has been adopted in many previous studies. In this study, the response spectrum of rock site corresponding to the 475-year return period for PMA is defined according to the probabilistic seismic hazard analysis (PSHA) based on the latest ground motion attenuation model of Southwest Western Australia. Site characterization in PMA is performed using two microtremor measurements, namely SPAC technique and H/V method. The clonal selection algorithm (CSA) is introduced to perform direct inversion of SPAC curves to determine the soil profiles of representative PMA sites investigated in this study. Using the simulated bedrock motion as input, the responses of the soil sites are estimated using numerical method based on the shear-wave velocity vs. depth profiles determined from the SPAC technique. The response spectrum of the earthquake ground motion on surface of each site is derived from the numerical results of the site response analysis, and compared with the respective design spectrum defined in the Australian Earthquake Loading Code. The comparison shows that the code spectra are conservative in the short period range, but may slightly underestimate the response spectrum at some long period range.     

An Evolutionary Algorithm for Site Search Problems

The goal of solving a site search problem is to allocate a contiguous set of land parcels such that the total land acquisition cost, or other objectives, are optimized. This article describes the design and implementation of an evolutionary algorithm (EA) that can be used to solve site search problems. In this article, a graph representation is used to define the spatial structure of solutions to the problem. By using this representation, the contiguity of a site is maintained during the initialization, mutation, and local search operations of the EA. The effectiveness of the EA in finding optimal or near-optimal solutions is demonstrated by testing it on a series of problems whose optimal solutions are known.     

Bayesian Spatial Filtering for Hedonic Models: An Application for the Real Estate Market

This article presents a Bayesian method based on spatial filtering to estimate hedonic models for dwelling prices with geographically varying coefficients. A Bayesian Adaptive Sampling algorithm for variable selection is used, which makes it possible to select the most appropriate filters for each hedonic coefficient. This approach explores the model space more systematically and takes into account the uncertainty associated with model estimation and selection processes. The methodology is illustrated with an application for the real estate market in the Spanish city of Zaragoza and with simulated data. In addition, an exhaustive comparison study with a set of alternatives strategies used in the literature is carried out. Our results show that the proposed Bayesian procedures are competitive in terms of prediction; more accurate results are obtained in the estimation of the regression coefficients of the model, and the multicollinearity problems associated with the estimation of the regression coefficients are solved.     

3D geometrical modeling of excavation units at the archaeological site of Tell ‘Acharneh (Syria)

3D geometric modeling consists of representing geometric and spatial relationships of volumetric objects. We think it could be helpful in the context of archaeological excavation units representation and analysis. This article presents a procedure developed to generate 3D models from GPS positions taken at the top and the bottom of the excavation units boundaries on the archaeological site of Tell ‘Acharneh (Syria). It shows and discusses two geometrical modeling approaches (voxel and tetrahedral) used in the Gocad 3D modeling tool. Once excavation units are geometrically modeled, it is possible to refer them within a trench or the entire archaeological site, to handle them in various ways (zoom, rotation, translation), to perform on them 3D spatial analysis such as volumetric calculus or intersection computation, to make various kinds of queries such as to find out excavation units that have a certain number of artefacts, to generate sections anywhere in the 3D model, and finally to publish it with VRML (Virtual Reality Modular Language). As well as improving data analysis techniques, we think that if this 3D modeling operation can be done during the excavation, it could greatly help archaeologists to plan more efficiently their daily excavation strategy.     

The Zone Definition Problem in Location-Allocation Modeling

Location-allocation modeling is a frequently used set of techniques for solving a variety of locational problems, some of which can be politically sensitive. The typical application of a location-allocation model involves locating facilities by selecting a set of sites from a larger set of candidate sites, with the selection procedure being a function of “optimality” in terms of the allocation of demand to the selected sites. In this paper we examine the sensitivity of one particular type of location-allocation model, the p-median procedure, to the definition of spatial units for which demand is measured. We show that a p-median solution is optimal only for a particular definition of spatial units and that variations in the definition of spatial units can cause large deviations in optimal facility locations. The broad implication of these findings is that the outcome of any location-allocation procedure using aggregate data should not be relied upon for planning purposes. This has important implications for a large variety of applications.     

Mound formation processes and societal transformations: A case study from the perichadian plain

My main purpose in writing this paper is to build a coherent set of questions, emphasizing their archaeological visibility, in order to devise a series of archaeological test procedures for the evaluation of some current chronological and behavioral inferences. Archaeological sites result from a combination of a vast number of processes, which can be partitioned into natural agencies and human behaviorally induced phenomena. After a short review of the ecological context of the Perichadian plain and its implications for late prehistoric human settlement in that specific area, an analysis of formation processes is carried out. The use of field observations and actualistic researches carried out elsewhere in the African continent allows the selection of various criteria, useful for the evaluation of the kinds of information pertaining to cultural transformations, which can be gathered from the mound of Mdaga, a site excavated from 1960 to 1968. Some of these selected criteria are then compared to other sites of the same area.     

A Simplified Procedure to Select a Suitable Retrofit Strategy for Existing RC Buildings Using Pushover Analysis

Over the past ten years, the development of analytical procedures to accurately evaluate the seismic performance of existing buildings has gathered the attention of researchers. This has resulted in the publication of several standards, which, however, inadequately cover the issue of retrofit strategy selection. In the present article, a procedure that allows a comparison of available strategies in order to select the optimum solution for an existing deficient building is proposed. The procedure is based on calculating the pushover curve for the unstrengthened structure. A capacity spectrum is then estimated assuming different retrofit scenarios, which is then used for the evaluation of the strategies. The latter is based on criteria that assess the main structural system characteristics and how each solution benefits them. The final step of the procedure introduces simplified rules that allow the approximate design of each retrofit solution, which allows the evaluation of their applicability. The proposed procedure was applied to two idealized buildings with different structural systems. Results obtained indicate that less effective or inapplicable rehabilitation strategies were properly detected. Thus, the results were considered acceptable in terms of identifying the possible optimum strategy, which, however, should be verified with a detailed design of the retrofit system.     

Examining Land-Use through GIS-Based Kernel Density Estimation: A Re-Evaluation of Legacy Data from the Berbati-Limnes Survey

The use of archaeological survey data for evaluation of landscape dynamics has commonly been concerned with the distribution of settlements and changes in number of recorded sites over time. Here we present a new quantitative approach to survey-based legacy data, which allows further assessments of the spatial configuration of possible land-use areas. Utilizing data from an intensive archaeological survey in the Berbati-Limnes area, Greece, we demonstrate how GIS-based kernel density estimations (KDE) can be used to produce cluster-based density surfaces that may be linked to past land-use strategies. By relating density surfaces to elevation and slope, it is also possible to quantify shifts in the use of specific environments on a regional scale, allowing us to model and visualize land-use dynamics over time. In this respect, the approach provides more multifaceted information to be drawn from archaeological legacy data, providing an extended platform for research on human-environment interactions.     

MATHEMATICAL MODELLING OF THE RELATIONSHIP BETWEEN NEOLITHIC SITES AND THE RIVERS IN XI’AN (SHAANXI PROVINCE,CHINA)*

Based on analyses of the ecological environments of the Neolithic sites along the Chan and Ba Rivers in the Xi’an area (Shaanxi Province, China), it was found that the characteristic factors of the sites had a very close relationship with the nearby river. The characteristic factors of Neolithic sites have been analysed and defined as mathematical parameters by statistical methods. A mathematical model of the human–land relationship between Neolithic sites and rivers has been established using the stepwise regression procedure REGRESS in SPSS^®. The mathematical model is Y = 496.153 – 4.833X₁ + 113.692X3 + 725.097X₅ – 27.683X₃X₄. It shows that the distance (Y) from a site to a river has a marked relationship with the site area (X₁), the river flux (X₃), the site location (X₅) and river ratio drop (X₄). The model shows that the relationship between the sites and the river is in accordance with the conclusions of archaeological research. The mathematical model not only offers theoretical guidance for the archaeological excavation of Neolithic sites in Xi’an, but also contributes to the archaeological environmental research of Xi’an Neolithic sites.      

A Decision-Making and Search Model For Intraurban Migration

Most of the research on the intraurban migration attempting to develop models of the mobility process has presented intuitively appealing statements about the residential decision process, but stopped short of a formal development of these concepts. If it is to be possible to predict the mobility pattern within the city, both the search and selection process must be more clearly specified. In this paper, a preliminary theoretical model containing decision rules similar to those found in optimal search models is developed. The model explicitly incorporates the spatial and temporal aspects of residential choice and has the potential to predict the probability that a prospective migrant will search for a new residence in a given area of the city, the time when the search process will come to a conclusion and, by implication, the expected location of the new residence. The preliminary results from the model suggest a major elaboration of the spatial and temporal aspects of residential choice under conditions of uncertainty in terms of a set of empirically measurable determinants, relating to a household's preferences, beliefs, and degree of risk aversion.     

Solution Techniques for Large Regional Partitioning Problems

This paper presents procedures for use in electoral districting and related applications. A region is to be divided into a number of “territories” formed as aggregates of discrete spatial units, subject to constraints on territory size and on intraterritorial connectivity, so as to minimize the total length of territory perimeters. The procedures are based on a hill-climbing principle, with progressively rigorous application of the connectivity and territory-size constraints. Computational tests indicate that the best of the procedures provide an effective trade-off between solution quality and computational efficiency.     

潮湿环境下的土遗址加固保护材料筛选试验研究——以福建昙石山遗址为例

长期以来,关于潮湿环境下土遗址加固保护的适用材料问题一直是困扰我国文物保护和考古界的难点,至今尚没有成熟的规范可以参考。福建昙石山遗址作为我国东南沿海地区典型潮湿环境下的土遗址,近年来在遗址本体加固保护过程中,在加固材料的选取上,按照基础成分的不同分别对四类主要加固剂进行施工试验,通过大量的室内和现场局部试验,证明基本成分为长链烷基、烷氧基硅氧烷小分子和主要成分为含有乙氧基团的聚硅酸乙酯混合物以及主要成分为水玻璃和硅氧烷共聚物的加固剂材料加固效果较好,可用于潮湿环境下昙石山遗址的本体加固保护,这对推进我国潮湿环境下土遗址保护工作的全面发展无疑也是一次有益的尝试和探索。     

北京应急避难场所的区位优化配置分析

在中国城市快速增长的背景下,城市公共服务设施的空间配置成为社会各界关注的热点问题。本文以北京市中心城区的应急避难场所为例,利用Voronoi多边形算法,研究应急避难场所的空间优化和配置。结论显示,北京市作为人口密集的国际大都市,其应急避难场所的建设存在一定的缺口,在空间上分布也不均衡;根据公共服务设施"均等化"的原则,北京市中心城区至少需要新建40多个大型应急避难场所;从公共服务设施配置的公平和效率原则出发,未来应急避难场所的建设重点不仅要增加数量和扩大规模,还应调整空间配置。     

The Impact of Migration on Wages: Empirical Evidence from French Youth*

Abstract. This paper deals with the impact of migration on wages. We introduce a spatial dimension into the job search framework, so that the agent faces neither the same job offer distribution nor the same search costs when looking for a job inside his local labor market. This is in comparison to the agent searching outside his local labor market, where migration costs are a factor. We estimate wage equations in which we introduce the decision to migrate as a binary choice, and later as a polychotomic choice (stayer/mover from provinces to Paris/mover from provinces to provinces). We find no selection effect for people with low levels of education, and a positive selection effect for highly educated migrants. When we distinguish the migration destination for highly educated from provinces, we find a hierarchical effect, that is, the selection effect is higher for men who migrate to Paris than for those who migrate to other provinces.     

Site prioritization and the reproduction of inequity in the restoration of Biscayne Bay

The restoration of urban estuaries is challenging due to the complexity of prioritizing sites in a context of social and biophysical unevenness. Site prioritization and selection are crucial components of ecological success and equity in restoration. In many cases, site prioritization is conducted according to simple opportunity or political expediency, but this needs to be investigated further in local contexts, with accompanying analysis of the impacts on urban environmental equity. Using a critical physical geography framework, I explore site selection processes in the restoration of Biscayne Bay through case studies of two urban streams. I use multiple data types to present an integrated perspective on urban restoration priority and the social context that produces restoration siting decisions. I find that the logics of restoration site selection in the Biscayne Bay watershed have produced ecologically questionable decisions and inequitable outcomes. Therefore, I argue that restoration decision making needs to include environmental justice criteria.     

A Comparison of Three Methods for the Extraction of Phytoliths from Sediments

This paper compares three methods commonly used to extract fossil phytoliths from sediments. A basic procedure using heavy liquid flotation and oxidation is compared with two other procedures across a range of sediment types commonly encountered in archaeological studies. The three procedures are: (1) a heavy liquid flotation method (HLF); (2) a burning method (POW); and (3) another heavy liquid flotation method (HLFPol) similar to HLF, but adapted to allow the extraction of pollen and spores as well as phytoliths, within a single process. Comparisons of the resulting output using these three techniques for phytolith extraction show that different methods can produce different results, and therefore basic techniques should be modified according to the characteristics of the sediments for which they are used. While all the techniques showed similarities in assemblage results, there were problems associated with disaggregation and effective separation of light and heavy fractions, in particular with the POW procedure. The evidence suggests that morphotype selection occurred both within the physical sorting process and in the process of inverting slides to shed excess residue; in both cases it is difficult to suggest a solution to the problem. The results show clearly that the advantages gained by using the POW procedure are largely outweighed by the problems encountered with its use, and because of possible size/shape selection, it is not recommended for general extraction procedures. The heavy liquid flotation procedures, on the other hand, are shown to produce more concentrated residues with higher levels of clarity and less potential than the POW procedure for sample bias. The use of a non-toxic heavy liquid, sodium polytungstate, now allows the process to be used in relative safety. It is recommended that analysts use heavy liquid flotation procedures with chemical treatments specific to sediment requirements.     

Spatial organization of the Gravettian mammoth hunters' site at Kraków Spadzista (southern Poland)

One of the largest and best known sites of the Central European Gravettian is the Kraków Spadzista site. This article summarizes archaeological, palaeontological, and zooarchaeological data from the site, obtained in the course of more than 40 years of excavations and studies. The site is known mainly from the discovery of the large mammoth bone accumulation in trench B. During field work conducted in a few trenches located close to this assemblage, numerous human artifacts and faunal remains were found. On the basis of analyses of lithic materials, faunal remains, and radiometric data it is concluded that the Krakow Spadzista site was frequently re-occupied during a few weeks or months, by groups of Gravettian hunters in the period 24–22,000 rcyBP This short-term camp site was related to mammoth hunting. The analysis allowed identification of three possible activity zones, characterized by the presence of different groups of flint tools, fireplaces, and different faunal assemblages: a camp area, a lithic workshop, and an animal-processing area, besides the well known accumulation of mammoth bones.     

SQUARE PEGS IN ROUND HOLES: PROGRAM EVALUATION AND ORGANIZATIONAL UNCERTAINTY

It is argued that variation in uncertainty about social program goals and causal processes should influence the selection of evaluation designs and methods. Eighteen prominent evaluation reports are examined to contrast predicted evaluation strategies derived from theory about organizational uncertainty with the actual evaluation methods used. It was found that the actual design, measurement, and analysis procedures were frequently different from procedures that were compatible with the kinds of program uncertainty described in the evaluation reports. It is suggested that theory and practice in program evaluation can be improved by systematically incorporating organizational concepts that would contribute to the selection of evaluation methods.