Buffon's needle and the estimation of migration distances

A procedure is suggested for estimating migration distances from data on the proportion of migrants crossing regional boundaries. The method makes use of Buffon's needle, a problem in geometrical probability from the eighteenth century that was originally used as an empirical means of estimating π. The procedure is described for various scenarios that differ in their assumptions about region shape, the spatial distribution of population, and the distribution of migration distances. An application to migration distances in the United States is given, and additional attention is given to the estimation of intraregional migration distances.     

INFORMATION INTERDEPENDENCE: Keohane and Nye's complex interdependence in the information age

A well-known and respected attempt to theorize interdependence in the field of international relations is complex interdependence. In Power and Interdependence , Robert O. Keohane and Joseph S. Nye, Jr define interdependence as reciprocal effects among actors resulting from 'international transactions - flows of money, goods, people and messages across international boundaries'. Though much research has been done on the effects of interdependence on the first three, the flows of messages have been studied less often. Keohane and Nye addressed the issue in a 1998 article in Foreign Affairs , discussing changes in the global environment resulting from the information age which have had an impact on their ideas. This article proposes to go deeper into complex interdependence. The world is becoming increasingly 'information interdependent' and this essay is an attempt to apply the assumptions and concepts presented in complex interdependence to the information age. In the final analysis, complex interdependence complements research from the field of communications, that information flows should be understood as underlying mechanisms and processes that facilitate contextual understanding of issues. It maintains the integrity of the assumptions of complex interdependence, while adding an understanding of the nature of information and information flows.     

Formulas for the Design of CUSUM Quality Control Charts

ABSTRACT

In the design of CUSUM control charts, it is common to use charts, tables, or software to find an appropriate critical threshold (h). This article provides an approximate formula to calculate the threshold directly from prespecified values of the reference value (k) and the in-control average run length (ARL₀). Formulas are also provided for choosing k and h from prespecified values of the in-control and out-of-control average run lengths.     

Dynamic flow modeling with interregional dependency effects: an application to structural change in the U.S. migration system

Causative matrix methods can be used to project levels of population change, to monitor changing migration trends, and to aid in forecasting movement during periods of consolidation and dissipation. They are appealing because they provide measures of the changing strengths of all interregional dependency effects. Separate competing destinations and competing origins perspectives on temporal change can be obtained. The column sums and the eigenvalues provide useful aggregate gauges of the relative strengths of regional shifts. Patterns of U.S. interregional migration from 1935 to 1982 are examined using the causative matrix approach. Trends in the gross migration streams underlying the dramatic increase in core-periphery net migration taking place in the 1970s are examined, as is a more recent shift in the major source area of core region net outflow.     

Monitoring point patterns for the development of space–time clusters

Existing statistical methods for the detection of space–time clusters of point events are retrospective, in that they are used to ascertain whether space–time clustering exists among a fixed number of past events. In contrast, prospective methods treat a series of observations sequentially, with the aim of detecting quickly any changes that occur in the series. In this paper, cumulative sum methods of monitoring are adapted for use with Knox's space–time statistic. The result is a procedure for the rapid detection of any emergent space–time interactions for a set of sequentially monitored point events. The approach relies on a 'local' Knox statistic that is useful in retrospective analyses to detect when and where space–time interaction occurs. The distribution of the local Knox statistic under the null hypothesis of no space–time interaction is derived. The retrospective local statistic and the prospective cumulative sum monitoring method are illustrated by using previously published data on Burkitt's lymphoma in Uganda.     

A changepoint statistic with uniform type I error probabilities

ABSTRACT

Likelihood ratio tests for a change in mean in a sequence of independent, normal random variables are based on the maximum two-sample t-statistic, where the maximum is taken over all possible changepoints. The maximum t-statistic has the undesirable characteristic that Type I errors are not uniformly distributed across possible changepoints. False positives occur more frequently near the ends of the sequence and occur less frequently near the middle of the sequence. In this paper we describe an alternative statistic that is based upon a minimum p-value, where the minimum is taken over all possible changepoints. The p-value at any particular changepoint is based upon both the two-sample t-statistic at that changepoint and the probability that the maximum two-sample t-statistic is achieved at that changepoint. The new statistic has a more uniform distribution of Type I errors across potential changepoints and it compares favorably with respect to statistical power, false discovery rates, and the mean square error of changepoint estimates.     

《福乐智慧》中所反映的早期苏非

对于一个正在谋求发展的政权,苏非的避世苦修、清心寡欲、淡泊名利、不问世事并不值得提倡,正如11世纪新疆喀喇汗王朝的著名文学作品《福乐智慧》所提到的日出国王统治的国度,伊斯兰教正统派信仰盛行并以积极的态度参与国家治理。当时苏非已经出现,处于发展的初期阶段,属于个人行为,未形成大的苏非教团,但显然在社会和统治阶层中得到了一定程度的认同。究其原因,苏非神秘主义以其虔诚的独特的思想体系和修行方式为穆斯林的宗教生活增加了直觉体验和宗教情感,是对穆斯林宗教生活的合理补充。     

Aid Harmonisation and Alignment: Bridging the Gaps between Reality and the Paris Reform Agenda

The Paris agenda on aid effectivess emphasises support for recipient‐owned development strategies, increased use of national systems and more co‐ordinated and predictable donor actions. Monitorable targets for such behaviour have been agreed, but the connections with expected development benefits are as yet unproven. Alternative views of the rationale for aid agencies, transaction costs and conditionality, in which there is rarely complete preference alignment and trust between donors and recipients, introduce further complications. Four additional policy measures are identified which cannot be managed easily within the Paris agenda: better international balancing of aid allocations; new instruments with longer commitment horizons; liquidity arrangements to enable ‘scaling up’ across several countries; and independent aid rating institutions linked to market‐like sanctions.     

The geography of the Afrikaner Broederbond in Namibia

The power and influence of the Afrikaner Broederbond in the Southern African political sphere has been analysed and assessed in a non‐spatial context. However, it is only when the spatial distribution of the organisation is revealed that the full dimension of its power may be interpreted in the unfolding political struggles within the subcontinent. This paper furnishes a ‘synoptic’ examination of the geography of the Afrikaner Broederbond in Namibia.     

Buffon's needle and the estimation of migration distances

"A procedure is suggested for estimating migration distances from data on the proportion of migrants crossing regional boundaries. The method makes use of Buffon's needle, a problem in geometrical probability from the eighteenth century....The procedure is described for various scenarios that differ in their assumptions about region shape, the spatial distribution of population, and the distribution of migration distances. An application to migration distances in the United States is given, and additional attention is given to the estimation of intraregional migration distances." (SUMMARY IN FRE)