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1.
Six faunal statistics are described and assessed by means of simulation. Of these, the ‘probable number of individuals’ (PNI) methods, which include the Lincoln and Krantz indices, are shown to perform remarkably well. The assumptions of these PNI procedures are given and circumstances under which PNI methods can be employed are described. Palaeoeconomic methods occupy a middle ground between classical statistical theory and experimental archaeology, hence the use of the term ‘guesstimation’: this ground is explored and it is shown that these methods can have a considerable bearing on the interpretation of taphonomic and ‘spatial’ (intra-stratum) regularities. Promising avenues for future research are indicated.  相似文献   

2.
Federal grants-in-aid have been a major instrument for the exercise of national influence on the states. This research investigates empirically the degree of perceived national influence (PNI) exerted through the grant process during the 1970s and 1980s. Respondents were state administrators heading agencies that received federal grants. Surveys at four points in time across the two decades produced a unidimensional measure of PNI. PNI levels were notably higher in the 1970s than in the 1980s. Two competing explanations were offered to account for the decline: (a) intergovernmental institutional policy changes promoted by the Ronald Reagan administration from 1981 through 1988, and (b) symbolic and rhetorical advocacy of an altered (reduced) national role in relation to the states. Both factors appear to have contributed to sharp decline in PNI between the mid-1970s and the mid-1980s.  相似文献   

3.
The join-count statistic is used to measure the tendency of polygons of a given map type to attract or repel polygons of the same or different map types. Yet in certain maps—for example, natural resources maps—it is often impossible for a polygon of a given type to touch another polygon of the same type. (This is the no-same-color or “No-Same-Type-Touching” (NSTT) constraint referred to in the title.) This violates an underlying assumption of the join-count statistic and may render its use to study certain spatial phenomena inappropriate—even for measuring spatial autocorrelation among polygons that are not the same type. This was explored using Monte Carlo simulation. For polygons of different types, it appears that results of the join-count statistic can be interpreted without any special consideration for the NSTT constraint provided there are a minimum of five to eight colors in the spatial system. For polygons of the same type, results can simply be ignored since it is known that no two polygons of the same type will touch.  相似文献   

4.
ABSTRACT The paper addresses the empirical significance of the social context in economic decisions. Decisions of individuals who share spatial and social milieus are likely to be interdependent, and econometric identification of social effects poses intricate data and methodological problems, including dealing with self‐selection in spatial and social groups. It uses a simple empirical framework to introduce social interactions effects at different levels of aggregation, and examines estimation problems in linear models, the impact of self‐selection and of nonlinearities. It also examines neighborhood effects in job matching and proposes a research agenda that offers new techniques and data sources.  相似文献   

5.
Nearly all segregation measures use some form of administrative unit (usually tracts in the United States) as the base for the calculation of segregation indices, and most of the commonly used measures are aspatial. The spatial measures that have been proposed are often not easily computed, although there have been significant advances in the past decade. We provide a measure that is individually based (either persons or very small administrative units) and a technique for constructing neighborhoods that does not require administrative units. We show that the spatial distribution of different population groups within an urban area can be efficiently analyzed with segregation measures that use population count‐based definitions of neighborhood scale. We provide a variant of a k‐nearest neighbor approach and a statistic spatial isolation and a methodology (EquiPop) to map, graph, and evaluate the likelihood of individuals meeting other similar race individuals or of meeting individuals of a different ethnicity. The usefulness of this approach is demonstrated in an application of the method to data for Los Angeles and three metropolitan areas in Sweden. This comparative approach is important as we wish to show how the technique can be used across different cultural contexts. The analysis shows how the scale (very small neighborhoods, larger communities, or cities) influences the segregation outcomes. Even if microscale segregation is strong, there may still be much more mixing at macroscales.  相似文献   

6.
ABSTRACT. Summarizing the foregoing discussions in this journal on testing for regional homogeneity the present note shows that in the model of Zellner's seemingly unrelated regressions one test statistic may be used not only to test for overall homogeneity but also to examine for individual coefficient homogeneity. This aim is achieved by varying the linear restrictions in the test statistic according to different problems. To illustrate these tests regional consumption functions for the 11 Bundesläder (States) of the Federal Republic of Germany are used.  相似文献   

7.
Spatial Entropy     
A major problem in information theory concerns the derivation of a continuous measure of entropy from the discrete measure. Many analysts have shown that Shannon's treatment of this problem is incomplete, but few have gone on to rework his analysis. In this paper, it is suggested that a new measure of discrete entropy which incorporates interval size explicitly is required; such a measure is fundamental to geography and this statistic has been called spatial entropy. The use of the measure is first illustrated by application to one-and two-dimensional aggregation problems, and then the implications of this statistic for Wilson's entropy-maximizing method are traced. Theil's aggregation statistic is reinterpreted in spatial terms, and finally, some heuristics are suggested for the design of real and idealized spatial systems in which entropy is at a maximum.  相似文献   

8.
GIS在时间地理学中的应用初探   总被引:1,自引:0,他引:1  
时间地理学是一种富有应用前景的面向微观人文现象的研究方法,但相对落后的研究手段迟滞了它的发展。通过考察时间地理学的研究对象、研究方法及其理论基础,结合时态地理信息系统近年来在时空表达与分析方面的进展,本文详细阐述了地理信息系统技术在时间地理学中的应用思路,并认为两者的结合将促使时间地理学在数据处理、时空分析、结果表达与深化等方面得到进一步的发展。  相似文献   

9.
We derive an expression for the entropy of non‐probabilistic distributions encountered in spatial and mathematical mappings. The entropy of non‐probabilistic distributions can be formulated using probabilistic notions of the hypothetical random redistribution of finite information. We show that the discrete approximation to the information content of spatial maps can be based on the discrete hypergeometric distribution. The resultant “associative” entropy is distinct from the Shannon entropy for probability distributions and addresses several shortcomings of the current entropy paradigm as applied to spatial analysis. The associative entropy statistic is distributed approximately as a chi‐squared random variable under limitations of variation. We formulate a univariate logical equivalent of the associative entropy statistic, freeing the paradigm from the degrees of freedom constraint to which it has been traditionally shackled. This entropy has application in spatial analysis and fuzzy set theory. The associative entropy is based on the concept of proportional information and is related to the Getis G‐statistics of spatial association and the Chi‐squared statistics of sample means. We explore the utility of the theory when applied to spatial distribution of vegetation in New Brunswick, Canada. The limitations and implications of the entropy expression are discussed and suggestions are made for future applications of the theory. This work is part of the development of an information theory framework for the analysis of landscape patterns of animal habitat.  相似文献   

10.
This essay reflects critically on Martin Heidegger's remarks about authenticity and death with the aid of Christophe Bouton's Temps et liberté (2002), translated by Christopher Macann as Time and Freedom (2014). It first raises general questions concerning the possible thematic relationship between human endeavoring (action) and the experiences of finitude and freedom. Heidegger's Being and Time is particularly useful for exploring this relationship, but certain problems emerge when using this text for accessing the essay's themes. To wit: there are good reasons for mistrusting readings of Being and Time as a “practical” guide for grounding action. Against the practical reading, the essay wishes to reclaim the ontological‐existential significance of Heidegger's text. Although Bouton's treatment of Being and Time excludes its ontological dimensions and is entirely practical, even to the point of disregarding certain theoretical risks inherent in this approach, Bouton's study is indispensable for situating Being and Time in a historical‐intellectual context, whereby the experiences of freedom and time are understood within certain metaphysical presuppositions rendering them difficult to establish together on reliable grounds. Following Bouton's lead, the essay shows that the hermeneutic differences between practical and ontological readings of Being and Time can be explored through reflections on what Heidegger might have meant by the term “Möglichkeit” (“possibility”), from which Bouton infers “freedom.” It is alleged that Bouton does not fully consider all of Heidegger's assertions regarding Möglichkeit, most problematically the claim that the human being's most essential “possibility” is its “impossibility,” that is to say, its death.  相似文献   

11.
This paper presents a synthesis of current approaches to the comparison of archaeological assemblages. It draws its data from Roman Britain but the methodology discussed is equally applicable to other periods and places. Different types of assemblages including those of small finds, broken vessels and animal bones are discussed, and the problems relating to quantification are considered. The different sorts of questions that may be asked of data of varying quality are examined, and it is shown that even 'poor quality' data can provide useful insights into past societies. It is argued that to explore the full richness of the data available, multivariate statistics are an invaluable tool and this is illustrated by exploration of two groups of assemblages using Correspondence Analysis. Finally, attitudes within the archaeological community which may prove a barrier to further advances are examined.  相似文献   

12.
Shape analysis is useful for a wide variety of disciplines and has many applications. One of the many approaches to shape analysis focuses on shapes that are represented by predefined landmarks on an object. Some landmarks may be measured with greater precision, exhibit more natural variation, or be more important than others to an analysis. This article introduces a method for including this information when estimating mapping relations or assessing the degree of similarity between two objects that are represented by a set of two‐dimensional landmarks. Weighted bidimensional regression combines aspects of weighted least squares regression and bidimensional regression as a way to weight variables that are represented by a set of two‐dimensional spatial coordinates. One possible weighting scheme is suggested, and the effect of weighting is demonstrated through a face‐matching application. Results indicate that appropriate weighting increases the ability to correctly match two faces and that weighting has the largest effect when used with a projective transformation.  相似文献   

13.
Local statistics test the null hypothesis of no spatial association or clustering around the vicinity of a location. To carry out statistical tests, it is assumed that the observations are independent and that they exhibit no global spatial autocorrelation. In this article, approaches to account for global spatial autocorrelation are described and illustrated for the case of the Getis–Ord statistic with binary weights. Although the majority of current applications of local statistics assume that the spatial scale of the local spatial association (as specified via weights) is known, it is more often the case that it is unknown. The approaches described here cover the cases of testing local statistics for the cases of both known and unknown weights, and they are based upon methods that have been used with aspatial data, where the objective is to find changepoints in temporal data. After a review of the Getis–Ord statistic, the article provides a review of its extension to the case where the objective is to choose the best set of binary weights to estimate the spatial scale of the local association and assess statistical significance. Modified approaches that account for spatially autocorrelated data are then introduced and discussed. Finally, the method is illustrated using data on leukemia in central New York, and some concluding comments are made.  相似文献   

14.
This paper presents a method for studying between‐group differences in physical activity patterns through the analysis of musculo‐skeletal stress markers (MSM). The specific aim was to develop a method that could overcome the problems related to confounding variables such as body size by shifting the analytical focus from the comparison of differences in intensity to the comparison of differences in kinds of activity. Instead of testing whether there are differences in the measures of central tendency of MSM scores between two groups, we proposed looking for differences in MSM covariation patterns. Formally, this is achieved through the statistical comparison of group‐specific MSM intercorrelation matrices. The null hypothesis is that the matrices are equal, and the statistical significance of the test statistic is obtained with a permutation test. In this way, the problem of confounding variables such as body size is mostly avoided because the procedure is based on the comparison of group‐specific sets of correlation coefficients which are scale‐free. The method was employed in a case study to investigate the differences in activity patterns between men and women from the Early Bronze Age population buried at the necropolis in Mokrin, Serbia. The null hypothesis of no difference between the male and female MSM correlation matrices was rejected (p = 0.0135). After the statistical significance of the difference was established, further investigation of male and female activity patterns was undertaken by means of principal component analysis (PCA) with varimax rotation. PCA results suggest that covariation between MSMs is stronger in the male sample. Success in demonstrating differences in activity patterns between sexes implies that the proposed method can be used to test for differences in physical activity between groups of individuals defined by criteria other than sex. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

15.
Success in war depends on alignment between operations and strategy. Commonly, such alignment takes time as civilian and military leaders assess the effectiveness of operations and adjust them to ensure that strategic objectives are achieved. This article assesses prospects for the US‐led campaign in Afghanistan. Drawing on extensive field research, the authors find that significant progress has been made at the operational level in four key areas: the approach to counterinsurgency operations, development of Afghan security forces, growth of Afghan sub‐national governance and military momentum on the ground. However, the situation is bleak at the strategic level. The article identifies three strategic obstacles to campaign success: corruption in Afghan national government, war‐weariness in NATO countries and insurgent safe havens in Pakistan. These strategic problems require political developments that are beyond the capabilities of the International Security Assistance Force (ISAF). In other words, further progress at the operational level will not bring ‘victory’. It concludes, therefore, that there is an operational‐strategic disconnect at the heart of the ISAF campaign.  相似文献   

16.
Identified human skeletal collections are those in which basic demographic data (sex, age and biological origin) are known and are crucial for developing and testing osteological methodologies. It is important that the identified collection be contextualised, and in this way the collection will be considered a reference collection. To contextualise a collection requires documentation of the basic demographic data of the individuals (sex, age, year of birth, geographical area) as well as information concerning the socio‐economic and temporal context in which the individuals lived. The contextualisation of an identified collection is very important so the researchers can understand the ‘point of reference’ when applying a method to it or developing a new method. The purpose of this study is to contextualise the identified skeletal collection of the Universitat Autónoma de Barcelona (UAB) which currently contains 35 adult skeletons of both sexes. To carry out the objectives of the present study, the information about the individuals was collected from cemetery registers and compared with the information of the demographic and statistic public institutions of Spain. The results indicate that the UAB collection is formed only by Spanish nationals who mainly lived during the 20th century in Granollers (Barcelona, Spain). Both sexes are equally represented and all of the individuals are adults. They reflect the most current adult population structure of Catalonia and be treated as a Catalan reference sample of adults living in the 20th century. This collection offers special opportunities for demographic analysis, including validation studies of skeletal ageing and sexing methods that target adult individuals. The collection can also be used in conjunction with other reference samples to investigate secular and populational change in cranial form, sexual dimorphism and stature. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

17.
This study proposes a new quadrat method that can be applied to the study of point distributions in a network space. While the conventional planar quadrat method remains one of the most fundamental spatial analytical methods on a two‐dimensional plane, its quadrats are usually identified by regular, square grids. However, assuming that they are observed along a network, points in a single quadrat are not necessarily close to each other in terms of their network distance. Using planar quadrats in such cases may distort the representation of the distribution pattern of points on a network. The network‐based units used in this article, on the other hand, consist of subsets of the actual network, providing more accurate aggregation of the data points along the network. The performance of the network‐based quadrat method is compared with that of the conventional quadrat method through a case study on a point distribution on a network. The χ2 statistic and Moran's I statistic of the two quadrat types indicate that (1) the conventional planar quadrat method tends to overestimate the overall degree of dispersion and (2) the network‐based quadrat method derives a more accurate estimate on the local similarity. The article also performs sensitivity analysis on network and planar quadrats across different scales and with different spatial arrangements, in which the abovementioned statistical tendencies are also confirmed.  相似文献   

18.
The capabilities for visualization, rapid data retrieval, and manipulation in geographic information systems (GIS) have created the need for new techniques of exploratory data analysis that focus on the “spatial” aspects of the data. The identification of local patterns of spatial association is an important concern in this respect. In this paper, I outline a new general class of local indicators of spatial association (LISA) and show how they allow for the decomposition of global indicators, such as Moran's I, into the contribution of each observation. The LISA statistics serve two purposes. On one hand, they may be interpreted as indicators of local pockets of nonstationarity, or hot spots, similar to the Gi and G*i statistics of Getis and Ord (1992). On the other hand, they may be used to assess the influence of individual locations on the magnitude of the global statistic and to identify “outliers,” as in Anselin's Moran scatterplot (1993a). An initial evaluation of the properties of a LISA statistic is carried out for the local Moran, which is applied in a study of the spatial pattern of conflict for African countries and in a number of Monte Carlo simulations.  相似文献   

19.
This article presents a new metric we label the colocation quotient (CLQ), a measurement designed to quantify (potentially asymmetrical) spatial association between categories of a population that may itself exhibit spatial autocorrelation. We begin by explaining why most metrics of categorical spatial association are inadequate for many common situations. Our focus is on where a single categorical data variable is measured at point locations that constitute a population of interest. We then develop our new metric, the CLQ, as a point‐based association metric most similar to the cross‐k‐function and join count statistic. However, it differs from the former in that it is based on distance ranks rather than on raw distances and differs from the latter in that it is asymmetric. After introducing the statistical calculation and underlying rationale, a random labeling technique is described to test for significance. The new metric is applied to economic and ecological point data to demonstrate its broad utility. The method expands upon explanatory powers present in current point‐based colocation statistics.  相似文献   

20.
The rank adjacency statistic D provides a simple method to assess regional clustering. It is defined as the weighted average absolute difference in ranks of the data, taken over all possible pairs of adjacent regions. In this paper the usual normal approximation to the D statistic is found to give inaccurate results if the data are sparse and some regions have tied ranks. Adjusted formulae for the moments of D that allow for the existence of ties are derived. An example of analyses of sparse mortality data (with many regions having no deaths, and hence tied ranks) showed satisfactory agreement between the adjusted formulae and the empirical distribution of the D statistic. We conclude that the D statistic, when used with adjusted moments, provides a valid approximate method to evaluate spatial clustering, even in sparse data situations.  相似文献   

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