The Probabilistic Minisum Flow Interception Problem: Minimizing the Expected Travel Distance until Intercept under Probabilistic Interception

We develop a variant of the flow interception problem (FIP) in which it is more desirable for travelers to be intercepted as early as possible in their trips. In addition, we consider flows being intercepted probabilistically instead of the deterministic view of coverage assumed in the FIP literature. We call the proposed model the probabilistic minisum FIP (PMFIP); it involves minimizing the sum of the expected distance that each flow travels until intercepted at a facility among placed facilities. This extension allows us to evaluate the effect of facility location under any given value of the interception probability and to apply the model to a variety of situations. We apply the proposed model to an example network by assuming a hypothetical situation in which people gather at a stadium from various nodes on the network, and receive some goods or services on the way to the stadium. We analyze optimal solutions obtained by varying the number of facilities and interception probability. It is shown that the expected travel distance until intercept is greatly reduced by means of a few optimally located facilities under a moderate interception probability.     

基于人地关系的生态旅游地域系统演变定量分析

本研究通过建立人类活动无序度和生态环境承载力评价指标体系和模型,用简化系统结构关系的方法测算生态旅游地域系统熵值,以此来分析生态旅游地域系统的功能状况;生态旅游地域系统中人类活动主要是旅游者的旅游活动、当地社区和居民的活动和当地旅游业活动三个方面,构建了27个具体指标来评价人类活动的无序度;生态环境承载力主要通过自然基础、生态系统、水资源和大气环境四个方面共8个具体指标来测算。最后通过生态旅游地域系统熵变即两个不同时刻人类活动无序度熵变和生态环境承载力熵变差值,来判断生态旅游地域系统在时间断面上的演变方向和可持续发展能力。     

元大都孔庙、国子学的建筑模式与基址规模探析

本文依据文献史料,对元大都孔庙、国子学的建设过程进行梳理,对建筑平面进行复原,确定其用地范围与基址规模,并通过分析探寻其设计规律与手法,发现设计中采用两套平格网．孔庙、国子学的基址规模与大都城市平格网的基准长度存在倍数关系,基址边界均在11步×12．5步的平格网线上;建筑群内部的平面布置受8步×10步的平格控制,总平面中重要控制线大多与网格线对应。根据这一规律,本文进一步对明清北京孔庙、国子监进行分析,发现明太祖、英宗两朝对元代孔庙、国子学展拓时,基址规模仍受元大都城市平格网控制,而永乐朝重建孔庙时沿用元代8步×10步的平格网,将东西廊庑分别向内收进一格,从而揭示元、明建筑模式与基址规模的内在一致性。     

Commissioning and Use of Charts Made in Majorca c.1400: New Evidence from a Tuscan Merchant’s Archive

The Datini Archive in Prato, Italy, a remarkable collection of a late fourteenth–early fifteenth century merchant’s business correspondence, includes a number of orders for charts from Majorca, one of the major chart-making centres in the Mediterranean in the Middle Ages. The letters give information on prices, the length of time it took to make a chart, and its destination. The archive also contains unpublished information on how the charts were packed and transported. From these sources we conclude that the charts appear to have served not only to prepare business trips, but also to embody the memory of these trips.     

What Has the Geography of Sleeping Arrangements Got to Do with the Geography of Our Teaching Spaces?

As geographers we are used to researching and teaching about those other than ourselves and it is timely to turn our gaze on the social and spatial practices of our own teaching spaces. One particular teaching space is the overnight geography field trip, a context in which geography fieldwork is ostensibly the main focus for two or more consecutive days. Teaching spaces such as classrooms and field trips, like all social spaces, are imbued with spoken and unspoken assumptions about sexuality, gender and 'race'. Geography field trips are one site in which to examine how social space is constituted via spoken and unspoken assumptions and how these assumptions shape field trip participants' understandings of themselves within these spaces. Simultaneously, field trips offer a site for the consideration of the socio-spatial relations of the reproduction of contemporary geographic knowledge. This article is one response to what Jon Binnie identified as an urgent need for geographers to understand how geography is being taught. Although sleeping arrangements are 'not formally notified' as part of fieldwork activity, the author demonstrates how sleeping arrangements conveyed important messages about sexuality, gender and cultural practices during seven overnight field trips held by two universities and two high schools in New Zealand. The concern is how apparently mundane arrangements such as the organisation of sleeping might reveal the ongoing hegemonic social and spatial relations of teaching and learning geography, as these are shaped by sexuality, gender and 'race', so that we might be better informed to challenge and change these practices.     

THE OPTIMAL LOCATIONS OF MULTIPLE BRIDGES,CONNECTING FACILITIES,OR PRODUCT VARIETIES*

ABSTRACT This paper considers the optimal locations of two or more facilities, and the optimal number of facilities, when trips are made in pairs. The results are the same as standard models of spatial competition when there is perfect matching, but not when there is random matching. The first interpretation is bridges across a river, with residential locations on one side matched perfectly or randomly to jobs on the other side. The second interpretation is connecting facilities, such as tennis courts or restaurants where pairs of consumers meet. The third interpretation is product differentiation, with husbands and wives jointly choosing from among varieties.     

Droughts as random events in the Maya lowlands

Because the values of most of the parameters controlling the occurrence and severity of a drought in a given location are unknown, and no periodicity has been observed, droughts can be considered random events. Running a random number generator within the limits of the annual rainfall variability relevant to the Maya lowlands, and defining a “Lean Year”, it is observed that strings of lean years occur quite frequently. Defining “Severe Drought”, “Disaster”, and “Catastrophe” based on the length of these strings, it is observed that a severe drought occurs on average every 32 years, a disaster occurs on average every 130 years, and a catastrophe on average every 500 years. These values fit the measured variability of the Yucatan climate, as observed in lake core sediments and in the post conquest written records. It also fits the average occurrence of “megadroughts” in the US Great Plains.The fit between the random occurrence model and the actual, “measured” occurrence of droughts supports the notion that for all practical purposes, droughts had been random events in the Maya region and could not be predicted. The lack of evident periodicity could be one of the reasons why means for long-term storage of food products were not developed there. It may also have affected the relationship between the priesthood and the general populace in that region.Since the method described here can be applied to any climatic region once the rainfall variability and the sensitivity of the local agriculture are known or can be estimated, if similar results are found they may probably have affected other regions with other ancient cultures in a similar way.     

Location-Allocation Models of Some Traffic Facilities

The objective of this paper is to formulate location-allocation models of linear facilities, such as bridges, railroad crossings, and staircases. The location-allocation models in this paper differ from existing location-allocation models in that the service provided by the facilities is consumed by trips, with associated origins and destinations. The first part of the paper shows the formulation of these location-allocation problems in one-dimensional space. It is demonstrated that these problems can also be formulated by the use of a rectilinear Voronoi diagram in two-dimensional space. The second part of the paper demonstrates fundamental relationships between the number of facilities and the total length of indirect trips and between the number of facilities and the total number of indirect trips for uniformly and independently distributed origins and destinations.     

国外旅游线路空间模式研究进展

旅游线路空间模式实质上是游客在目的地区域对停留空间和消费空间的理性选择与线性组合,是具有典型空间属性的社会文化地理现象和经济地理现象,涉及了作为旅游景点和旅游目的地的点状地理要素和作为旅游线路的线状地理要素以及旅游目的地体系构成的区域等面状地理要素。从文献综述的角度对不同尺度旅游线路模式的空间模型、目的地类型、游客旅行行为特征、模式选择影响因素以及理论基础进行了总结,在此基础上结合国内研究对旅游线路模式今后的研究方向提出了建议。     

Polycentricity and the Multiplexity of Urban Networks

Abstract

Empirical studies on polycentric urban regions (PURs) tend to analyse their spatial organization by examining only one type of functional linkage between cities. However, it has generally been accepted that urban networks are multiplex phenomena and that spatial interactions between cities can take many different forms, for example, commuting, shopping trips, and inter-firm trade. The spatial organization of each of these functional linkages is not necessarily identical, and, therefore, a region can appear to be polycentric and spatially integrated based on the analysis of one type of functional linkage but monocentric and loosely connected based on the analysis of another type of functional linkage. The aim of this paper is to stimulate further discussion on the multiplexity of urban networks with regard to the relational complexity of urban regions. Focusing on one PUR (Randstad Holland), we compare the geographical scope and spatial structure of different functional networks within it. Our results indicate that the spatial organization of the urban network depends on the lens through which it is assessed.     

Consumer and Producer Behavior in a Multipurpose Shopping Environment

This paper analyzes the shopping behavior of consumers across space within the context of multipurpose shopping. The degree of multipurpose shopping is derived, as are the optimal number of single- and multipurpose trips, and the quantities of high- and low-order goods purchased on such trips. It is shown that all consumer choice variables are a function of consumer location relative to producer location. The consumer analysis is then utilized as an input into the profit-maximizing equation that determines optimal producer location. The model is illustrated through the use of numerical analysis.     

Ireland and the Grail

Betty Potter's Dip, an unmarked roadside location at Boxted in Essex, is named after Elizabeth Potter, an eighteenth-century suicide who was buried there. Folklore has since assumed that she was a witch. This paper examines the events surrounding Elizabeth Potter's death and burial in relation to the practice of burying suicides by the roadside, and discusses why some roadside burials may have been associated with witches.     

Leading Indicators and Spatial Interactions: A Crime-Forecasting Model for Proactive Police Deployment

We develop a leading indicator model for forecasting serious property and violent crimes based on the crime attractor and displacement theories of environmental criminology. The model, intended for support of tactical deployment of police resources, is at the microlevel scale; namely, 1-month-ahead forecasts over a grid system of 141 square grid cells 4000 feet on a side (with approximately 100 blocks per grid cell). The leading indicators are selected lesser crimes and incivilities entering the model in two ways: (1) as time lags within grid cells and (2) time and space lags averaged over grid cells contiguous to observation grid cells. Our validation case study uses 1.3 million police records from Pittsburgh, Pennsylvania, aggregated over the grid system for a 96-month period ending in December 1998. The study uses the rolling-horizon forecast experimental design with forecasts made over the 36-month period ending in December 1998, yielding 5076 forecast errors per model. We estimated the leading indicator model using a robust linear regression model, a neural network, and a proven univariate, extrapolative forecast method for use as a benchmark in Granger causality testing. We find evidence of both the crime attractor and displacement theories. The results of comparative forecast experiments are that the leading indicator models provide acceptable forecasts that are significantly better than the extrapolative method in three out of four cases, and for the fourth there is a tie but poor forecast performance. The leading indicators find 41–53% of large crime volume changes in the three successful cases. The corresponding workload for police is quite acceptable, with on the average 5.2 potential large change cases per month to investigate and with 31% of such cases being positives.     

Doing a Florida thing: the creative class thesis and cultural policy

In this paper, we discuss the screen media businesses and production milieu that has developed in the predominantly rural region of the Northern Rivers, Australia, over the past 20 years. Spread across a number of towns and small cities each at some distance from each other, this screen milieu would seem to go against the prevailing logic for screen media to concentrate in globally connected cities. Taking up Allen J. Scott’s suggestion that the new capitalism of the twenty-first century is producing restructuring effects in many of the interstitial spaces between large cities, this article examines the spatial assemblages of the screen media and related creative industries sectors in one such space. We demonstrate how screen media actors in this rural region are participating in the wider cultural economy and explore its cultural policy implications.     

Structural Geomorphology Investigations in the Northern Ustyurt in Connection with Oil and Gas Prospecting

Structural-geomorphic techniques are tested in the northern part of the Ustyurt plateau (Lat. 46°N Long. 56°E) between the Caspian Sea and the Aral Sea in an attempt to identify local uplifts that may be potentially oil or gas bearing. The techniques include a structural-geomorphic photo interpretation, morphometric analysis of topographic maps and field mapping. Specific relationships between structure and surface relief are established in the three basic regions of the study area: the plateau, the escarpment zone and the foreland plain. In the plateau, surface relief generally directly reflects buried structures. In the plain, crustal movements are evident in the impact of abrasion and deposition processes that took place during transgressions of the nearby Caspian Sea. In the escarpment zone, both direct and inverse relationships are established between scarp promontories and embayments, on the one hand, and the plateau structure, on the other hand. Aside from some local uplifts, the investigation also reveals patterns of local and regional fault lines that often are arranged perpendicular to one another.     

What determines the latitudinal extent of the auroral acceleration region?

Characteristic scales associated with auroral precipitation are investigated on the basis of quasistatic magnetotail models, resistive MHD simulations of magnetotail dynamics, and a general relation between parallel electric fields and velocity shear. Since the inverted-V precipitation region of discrete auroras (on the dusk side) is associated with upward flowing, region 1, currents, we investigate the distribution of these currents first. The overall distribution of region 1 type field-aligned currents and their dynamic changes can be explained by characteristic scales in the magnetotail and their mapping to the ionosphere. The quiet time region 1 currents are associated with the decrease of tail flaring. Their overall extent in the north-south direction is closely related to the scale height of the cross-tail current. Dynamic region 1 currents are related to the velocity shear of earthward flow, which can be generated by a tail instability. In that case the peaks of the enhanced region 1 currents are found to map closer to midnight and to lower latitudes than the quiet region 1 currents, consistent with average observations [Iijima and Potemra (1976a), J. geophys. Res.81, 2165]. On the basis of a general relation between parallel electric fields and ‘slippage’ in the plasma transport [Hesse and Schindler (1988), J. geophys. Res.93, 5559; Schindleret al. (1991), Astrophys. J.380, 293], we make estimates of the spatial extent of nonideal regions, where parallel electric fields may exist. For a plausible model of substorm reconfiguration, we find a latitudinal extent of about 7 km for a time scale of 1 min and a integrated parallel electric field of 5 kV. The length scale is proportional to the time scale. The sign of this parallel electric field is consistent with downward acceleration of electrons on the dusk side. The spatial extent of the parallel electric field region is independent of the microscopic generation mechanism if the time scale and the characteristic parallel potential difference (i.e. the integrated parallel electric field) are independent of this mechanism.     

Cargoism in Irian Jaya Today

It appears that many people in Irian Jaya today are protesting against the manner in which they are, as they perceive it, being denied fundamental human rights, guarantees of social interaction based on fairness, and a reasonable share of economic benefits secured through ‘development’, and are searching for something that goes beyond this: a world in which they will enjoy health and a life of youthfulness; in which they will live with one another in peace and happiness, and have access to wealth without limit. In the past decade the number of ‘cargo’ movements has increased considerably and growing clouds of cargoism are spreading over the territory. In this essay we present data on activities from four areas in Irian Jaya. In the brief discussion that follows and in which we focus primarily on causal factors, we venture the thesis that in all these cases we have to do with (new) religious movements. The recurring combination of expectations based on traditional religious beliefs with feelings of political and economic discrimination may result in explosive situations. There will be little reason to assume that cargoism will decrease significantly.     

Seasonal migration in South-west France during the late glacial period

It has long been accepted that mobility was a factor in human life in Quaternary SW France, but debate continues as to the purpose, extent, direction, frequency and regularity of the movements. Several different types of evidence are relevant to the problem, and while some scholars have come to rather vague conclusions concerning “occasional forays” or “exchange systems”, others have taken up a firm position after analysis of only one body of data. A reappraisal of all aspects of the problem, in the light of all the evidence available from the region, in fact leads to only one satisfactory hypothesis: that of long-distance seasonal migration by both man and game.Only the reindeer-dominated sites of SW France will be discussed here, as it is from these that the migrations were the most necessary and the most extensive. Movements from other sites, such as those where a horse-dominated economy was practised, would probably have been rather shorter owing to the restricted migration undertaken by the staple resources.     

Prioritizing Disaster Mapping Tasks for Online Volunteers Based on Information Value Theory

In recent years, online volunteers have played important roles in disaster response. After a major disaster, hundreds of volunteers are often remotely convened by humanitarian organizations to map the affected area based on remote sensing images. Typically, the affected area is divided using a grid‐based tessellation, and each volunteer can select one grid cell to start mapping. While this approach coordinates the efforts of volunteers, it does not differentiate the priorities of different cells. As a result, volunteers may map grid cells in a random order. Due to the spatial heterogeneity, different cells may contain geographic information that is of different value to emergency responders. Ideally, cells that potentially contain more valuable information should be assigned higher priority for mapping. This article presents an analytical framework for prioritizing the mapping of cells based on the values of information contained in these cells. Our objective is to provide guidance for online volunteers so that potentially more important cells are mapped first. We present a method that is based on information value theory and focus on road networks. We apply this method to a number of simulated scenarios and to a real disaster mapping case from the 2015 Nepal earthquake.     

The Roadside Burial of Suicides: An East Anglian Study

While folklorists and social historians have assumed that the roadside burial of suicides was a widespread custom in England, there have been few efforts to research or locate specific examples. This study traces documented cases of the practice, and known (or suspected) roadside graves from one area of England in an attempt to establish how common this was.