Spatial structure in an open city with a subcenter

A comparative static analysis is performed in the setting of an open city with a subcenter. Transportation system in a duo-centric city is assumed to consist of not only “spoke-roads” but “circle streets”. Under the assumptions of no land input into production and the exogenous wage rate, most comparative statics results, including the effects of changing the location of a subcenter, can be determined unambiguously. Received: March 1997/Accepted: October 1998     

Spatial mapping of temporal risk characteristics to improve environmental health risk identification: a case study of a dengue epidemic in Taiwan

Mapping uneven events, such as disease cases or pollutants, is a basic but important procedure for analyzing regional relationships and variation in public health and environmental agencies. The purpose of mapping is to find out the spatial clustering of uneven events and identify spatial risk areas, which could lead to potential environmental hazards or epidemics. Meanwhile, more hypotheses could be generated through mapping process for further investigations. This paper proposed a novel spatial-temporal approach to focusing on: (1) how often these uneven cases occur, (2) how long these cases persist and (3) how significant cases occur in consecutive periods across the study area. The proposed model was applied to the dengue fever epidemic in Taiwan in 2002 as a case study, which was the worst epidemic in the last 60 years. This approach provides procedures to identify spatial health risk levels with temporal characteristics and assists in generating hypothesis that will be investigated in further detail.     

Spatial Cournot competition in a circular city with directional delivery constraints

This paper analyzes spatial Cournot competition in a circular city with a directional delivery constraint, which means that a firm can only deliver its product in one direction. It reveals that, contrary to the standard result, the unique location equilibrium involves duopoly firms agglomerating at the same location when they deliver products in different directions or when the direction decisions are made endogenously. We point out that spatial agglomeration emerges from a central point of view for a firm in a circular city, showing relaxing quantity competition through cost differentiation.     

Spatial Cournot competition and transportation costs in a circular city

We reconsider a Cournot spatial competition in a circular city. We discuss an oligopoly model. We find that two equilibria exist if the transport cost function is nonlinear in distance, while a continuum of equilibria exists if it is linear. Thus, the result of the real indeterminacy of equilibria in the linear transport cost case is knife edge.     

Intelligent transportation systems and parking management: implementation potential in a Brazilian city

The problems arising from the gap between demand and supply of parking spaces are becoming increasingly acute in most towns and cities. These difficulties are noted mainly in more densely populated areas that are poorly served by public transportation facilities and where the planning and use of existing areas is inadequate. The importance of controlling parking spaces as an integral element of the traffic and trip demand management process, together with the need to ensure a close-linked conceptual approach, has been defined and defended for quite some time. This paper presents a methodological procedure that underpins the feasibility of implementing an integrated parking system based on telematics resources. This procedure includes the development of a logic architecture for processing and transferring data and information. In order to test the proposed procedure, a medium-sized Brazilian town in the Rio de Janeiro Metropolitan Region—Niterói—was considered. A specific survey area covering some two square kilometres with a significant number of parking facilities was selected for the analysis. The results expected through the implementation of the proposed system indicate that the resulting benefits would include possibly lower levels of traffic congestion in the area under consideration, while also reducing air pollution.     

某城市环境地质问题防治对策建议

通过现场调查,对某市存在的地下水位下降、地下水污染、地质灾害以及特殊岩土体等环境地质问题进行了分析,提出了预防城市环境地质问题的方法和措施,归纳了重点区域的防治对策,以供同类工程参考借鉴。     

Urban environmental mercury in Changchun, a metropolitan city in Northeastern China: source, cycle, and fate

Mercury concentrations in each environmental compartment in Changchun City had obvious spatial and temporal trends. Particulate Hg (HgP) and total gaseous mercury (TGM) concentrations in air, total Hg (HgT) concentrations in precipitation and ratios of HgP to HgT (total Hg in air) in the atmosphere in heating season were higher than those in non-heating season, which resulted from civil heating. In contrast, reactive Hg (HgR) concentrations in precipitation were higher in non-heating season than those in heating season. TGM and SO2 in air had good agreement. HgP concentrations in the atmosphere were correlated with HgT concentrations in precipitation. Based on Hg concentrations in each environmental compartment, Hg exchange fluxes between environmental interfaces were estimated. Only 11.6% of Hg, emitted from coal combustion, deposited into land surface in urban district and the rest part participated in regional or global cycle, so urban district was the source of Hg global and regional cycle. Net fluxes of Hg into land surface and water were 34.26 kg year(-1) and 0.051 kg year(-1), respectively, which were clearly accumulated in the water and soil. Therefore considering urban local Hg cycle, each environmental compartment of urban ecosystem (water, air and soil) was the sink of Hg.     

GIS applied to geotechnical and environmental risk management in a Brazilian oil pipeline

The paper presents the development of a decision support system for the management of geotechnical and environmental risks in oil pipelines using a geographical information system. The system covers a 48.5 km long section of the São Paulo to Brasília (OSBRA) oil pipeline, which crosses three municipalities in the northeast region of the São Paulo state (Brazil) and represents an area of 205.8 km². The spatial database was created using geo-processing procedures, surface and intrusive investigations and geotechnical reports. The risk assessment was based mainly on qualitative models (relative numeric weights and multicriteria decision analysis) and considered pluvial erosion, slope movements, soil corrosion and third party activities. The maps were produced at a scale of 1:10,000.     

Spatial analysis of air pollution and cancer incidence rates in Haifa Bay, Israel

The Israel National Cancer Registry reported in 2001 that cancer incidence rates in the Haifa area are roughly 20% above the national average. Since Haifa has been the major industrial center in Israel since 1930, concern has been raised that the elevated cancer rates may be associated with historically high air pollution levels. This work tests whether persistent spatial patterns of metrics of chronic exposure to air pollutants are associated with the observed patterns of cancer incidence rates. Risk metrics of chronic exposure to PM₁₀, emitted both by industry and traffic, and to SO₂, a marker of industrial emissions, was developed. Ward-based maps of standardized incidence rates of three prevalent cancers: Non-Hodgkin's lymphoma, lung cancer and bladder cancer were also produced. Global clustering tests were employed to filter out those cancers that show sufficiently random spatial distribution to have a nil probability of being related to the spatial non-random risk maps. A Bayesian method was employed to assess possible associations between the morbidity and risk patterns, accounting for the ward-based socioeconomic status ranking. Lung cancer in males and bladder cancer in both genders showed non-random spatial patterns. No significant associations between the SO₂-based risk maps and any of the cancers were found. Lung cancer in males was found to be associated with PM₁₀, with the relative risk associated with an increase of 1 μg/m³ of PM₁₀ being 12%. Special consideration of wards with expected rates < 1 improved the results by decreasing the variance of the spatially correlated residual log-relative risk.     

Spatial variability in mortality inequalities, socioeconomic deprivation, and air pollution in small areas of the Barcelona Metropolitan Region, Spain

Background

There is evidence that geographic variability of social health inequalities continues to exist even after individual risk factors have been taken into account. However, relatively few studies have examined the contribution of exposure to air pollutants to those inequalities.

Objectives

To study the geographic variability of inequalities in mortality and their associations with socioeconomic and environmental inequalities in small areas of the metropolitan of Barcelona during the period 1994 to 2003.

Methods

As in the MEDEA Project, the small area unit was the census tract. Study population consisted of the residents of the metropolitan area of Barcelona. Response variables were all-cause and specific-cause standardized mortality ratio (SMR). Explanatory variables were deprivation index, summarizing socioeconomic variables of the census tracts, and estimates of air pollutant exposures. Bayesian hierarchical models were used in order to reduce the extra variability when using SMR and to assess associations between mortality and deprivation and air pollution.

Results

Statistically significant associations with deprivation were found for the causes of death related to consumption of tobacco and alcohol for men and, besides lung cancer, diet-related causes for women. Statistically significant pollution coefficients were only found in the metropolitan area of Barcelona and in men. A positive interaction between pollutants and the deprivation index was statistically significant for respiratory mortality and PM₁₀, and ischemic disease mortality and NO₂, both for men.

Conclusions

We found deprivation to be associated in a statistically significant way with the geographical variation in mortality in the census tracts of the metropolitan area of Barcelona, in the period 1994 to 2003. Those air pollutants more directly related with traffic modify some of these associations.     

Spatial variations of storm runoff pollution and their correlation with land-use in a rapidly urbanizing catchment in China

The composition of land use for a rapidly urbanizing catchment is usually heterogeneous, and this may result in significant spatial variations of storm runoff pollution and increase the difficulties of water quality management. The Shiyan Reservoir catchment, a typical rapidly urbanizing area in China, is chosen as a study area, and temporary monitoring sites were set at the downstream of its 6 sub-catchments to synchronously measure rainfall, runoff and water quality during 4 storm events in 2007 and 2009. Due to relatively low frequency monitoring, the IHACRES and exponential pollutant wash-off simulation models are used to interpolate the measured data to compensate for data insufficiency. Three indicators, event pollutant loads per unit area (EPL), event mean concentration (EMC) and pollutant loads transported by the first 50% of runoff volume (FF50), were used to describe the runoff pollution for different pollutants in each sub-catchment during the storm events, and the correlations between runoff pollution spatial variations and land-use patterns were tested by Spearman's rank correlation analysis. The results indicated that similar spatial variation trends were found for different pollutants (EPL or EMC) in light storm events, which strongly correlate with the proportion of residential land use; however, they have different trends in heavy storm events, which correlate with not only the residential land use, but also agricultural and bare land use. And some pairs of pollutants (such as COD/BOD, NH₃-N/TN) might have the similar source because they have strong or moderate positive spatial correlation. Moreover, the first flush intensity (FF50) varies with impervious land areas and different interception ratio of initial storm runoff volume should be adopted in different sub-catchments.     

Spatial or socioeconomic inequality? Job accessibility changes for low- and high-education population in Beijing,China

Two forces can affect job accessibility: one is regional-level socioeconomic transformation that changes the total amount of job supply and job demand, and the other is intra-regional spatial transformation that affects the distribution of jobs and population. Transitional Chinese cities are experiencing accelerated changes in both forces, which may affect various population groups differently. Using Beijing, China, as a case study, the research tracks changes in job accessibility for the low- and high-education groups between 2000 and 2010 and examines to what extent the two forces affect the two education groups' accessibility changes. Results show that the socioeconomic transformation reduced job accessibility, particularly the for high-education population, while the spatial transformation stratified the city with diverging effects on job accessibility changes of the two education groups. Policies should consider both forces in promoting residents' socioeconomic well-being.     

The relationship between selected socioeconomic variables and measures of arson: A cross-sectional study

This article examines the relationship between arson and selected sociological factors. Factor analysis was applied to 14 socioeconomic factors to produce the composite factors of social climate, income structure, economic climate and social structure. These four sociological factors were used as the independent variables in a series of multiple regressions with five arson-related measures. Statistically significant regression models were determined at the state level for property loss (total fires), number of fires and number of arsons. Findings indicate that poorer, more rural states have the lowest arson rates while arson is greatest in more urban states with correspondingly higher levels of violent crime. Social structures leading to criminal activity rather than poverty or general economic factors appear most related to arson in a given state. Reference: Joe H. Murrey, Jr., Robert E. Pitts, Dani A. Smith and Kenneth W. Hollman, The Relationship Between Selected Socioeconomic Variables and Measures of Arson: A Cross-Sectional Study,Fire Technology, Vol. 23, No. 1, February 1987, p. 60.     

Night and day at the beach: Relating social life to location and infrastructure in a Brazilian city

Brazilian city beaches are public spaces favoring citizens well-being. Urban studies relate built form and infrastructure with urban vitality and coastal studies underline uses as important for beach management, yet few researches relate form and infrastructure with beach uses. Understanding daily life as essential for public spaces and that spatial form relates with uses, this paper assesses time-based relationships between built and natural physical attributes and social life on the beaches of João Pessoa, a coastal city in North-east Brazil. Physical attributes are investigated at city scale - beach type, street network centrality and topography - and seafront scale - land uses, public/private interfaces, public infrastructure, beach sections and water quality. Beach social life was surveyed online, enquiring peoples' beach choice, visiting time and place, activities and evaluation. Infrastructure and street network follow topography and help configure shore and promenade for different landscapes. More central beaches have diverse land uses, well-equipped promenades and lighting and were popular night and day, while less central beaches had less infrastructure and were visited only by day. Findings highlight how physical attributes facilitate uses and, together with peoples’ evaluation, can inform urban beach design and planning.     

数字城市单体建筑物模型的空间关系

建筑物的建模是数字城市中最重要的问题之一,通过对单体建筑物的分析,提出建筑物形体之间的空间关系,为城市单体建筑物建模数据处理提供了可行的方法,此方法提高了模型的可靠性和实用性,对数字城市建设具有重要意义。