Boundaries Of Urban Areas Research Articles

CG-CFPANet: a multi-task network for built-up area extraction from SDGSAT-1 and Sentinel-2 remote sensing images

ABSTRACT Accurate extraction of built-up areas is helpful to urban development and map updating. Nighttime light (NTL) data can capture the lighting signal of ground objects. However, most built-up area extraction is conducted on public limited coarse spatial resolution NTL images. The Sustainable Development Science Satellite-1 (SDGSAT-1) provides 10 m spatial resolution panchromatic NTL images, making it possible to map detailed urban lighting structures. In urban extraction, the boundaries of urban areas are easily confused with background objects due to the similar spectral and textual features. To address this problem, we proposed a multi-task deep learning model, CG-CFPANet, to extract illuminated built-up areas by synthesizing SDGSAT-1 NTL data and optical remote sensing images. In CG-CFPANet, a convolutional feature pyramid attention (CFPA) module for better contextual recognition and a concatenation group (CG) module to merge the two remote sensing images are developed. Our proposed CG-CFPANet achieved 1.3% higher precision in built-up area extraction than ten other recently proposed network structures: UNet, UNet++, PSPNet, DeeplabV3, FCN, ExtremeC3Net, SegNet, BiseNet, Res2-UNet, and CBRNet. It shows higher applicability for large-scale built-up area extraction.

Sustainable Development of a Build-Up Area Taking into Account the Environmental Safety in Urban Conditions

Introduction. The sustainable design system of a built-up area requires integration of many types of information and ensuring the constant involvement of users, community members and various specialists throughout a building’s life cycle. The holistic designing approach implies focusing on the functional relationship between different parts of a building or a building complex as a whole that increases the complexity of a project. The key principle underlying sustainable buildings is an integrated design process taking into account the principles of environmental safety.The present article focuses on the analysis of the managerial and organizational methodology used by the civil engineering professionals in the context of sustainable construction. The design, management and arrangement of a construction site for a building’s reconstruction or a large scale build-up within the urban area boundaries require the development of measures and solutions for the storage and use of toxic chemicals, allocating the places for hazardous wastes collection and disposal, wastewater treatment – the results of operation of a previous structure or a building complex. All these factors need appropriate monitoring, assessment of risks and measures of ecological recovery of a land plot, in cases when the original objects and territories change their functional designation and are rebuilt into objects having impact on the environment.Materials and Methods. The development of sustainable design principles for arranging a construction site of capital construction facility on the areas that were exposed to long-term impact during the previous buildings’ and structures’ operation requires working-out the algorithms, methodology for assessment and monitoring the environmental situation on a construction site. The implementation of the present solutions requires the analysis of the sources of pollution, the duration of exposure, the nature and degree of construction site’ soil layer pollution. The development of modern managerial, organisational and technological solutions will minimise the processes of territory recovery and create sustainable construction operations.Results. As a result of the conducted research there were developed: the algorithms for assessing the ecological state of a construction site soil layer, the recommendations on the methodology for a build-up area ecological state assessment and monitoring aimed at setting the sustainable design of the organisational and technological solutions within an investment and construction project.Discussion and Conclusions. The implementation of the sustainable design processes in the investment and construction project on a build-up area soil layer preservation, the monitoring and assessment of its state enable avoiding extra costs due to the absence of the need for soil reclamation and purchase of soil of a different chemical composition from that originally formed in a particular area, and due to ensuring maximum possible preservation of vegetation.

Пути улучшения экологических показателей мегаполисов за счет использования СПГ в качестве резервного топлива

Large thermal power plants (TPP) located within the boundaries of urban areas usually use diesel or black oil as a reserve fuel (RF). In some cases, coal is also used. That has a negative impact on the natural environment of the city. In accordance with this, the new procedure for the creation and use of fuel reserves by thermal power plants provides as an option the use of liquefied natural gas (LNG) as a reserve and emergency fuel. Replacing RF (reserve fuel) with natural gas will, to some extent, reduce the load on the environment and reduce the area occupied by reserve fuel facilities (RFF). Since the construction and maintenance of RFFs at boiler plants and thermal power plants (TPP) requires significant capital investments and operating costs, the transition to LNG, which has its own specifics, requires additional analysis, given in this article, which evaluates the requirements for LNG volumes, places of production, storage and delivery of LNG to the TPP. The potential benefits of RF's transition to LNG have been assessed and challenges requiring further research have been formulated.

Administrative boundaries and urban areas in Italy: A perspective from scaling laws

Delineating boundaries of urban areas is no easy task, due to the inherent complexity of the problem, heterogeneity of relevant data and little consensus on how to properly measure the results. Any such delineation must eventually be cast onto administrative boundaries, an essential requirement for real-world applications. In the effort of relating administrative and alternative boundaries, we investigated in Italy the validity of general scaling laws, such as the area-population relation, and proposed a practical application. Relying on open data for population, settlements and road networks, we showed the extent to which scaling relations hold for different boundaries for urban areas, and how they compare to each other. We considered, beside Italian municipalities, urban areas based on the idea of “natural cities”, obtained using head/tail breaks of areas related to human mobility as an explicit indicator of existence of a city. Area-population data for administrative boundaries can be reconciled with scaling relations valid for both the world’s cities data and with those obtained from natural cities, provided an effective area is adopted in place of polygon planimetric area of municipalities. We eventually proposed an aggregation of administrative units using the empirical scaling relation as an objective function for accepting or rejecting pairwise fusion of boundaries. We suggest considering such a method, along with expert considerations, as an additional tool for real-world urban planning as seen from the very general perspective of seemingly abstract scaling laws.

Towns as Safety Organizational Fields: An Institutional Framework in Times of Emergency

According to the idea of safety structures as systemic, we developed a framework that emphasizes how the engagement of all relevant social agents could play an active role in the whole safety performance. The hypothesis of this paper is that a systemic approach should imply a precise shift of perspective from a unit of analysis embedded in a general environment, with mutual effects on a given safety performance, to a general analysis of a system where interdependent agents affect system performance. Through the lens of organizational field theory, safety performance is intended as the sum of the activities of multi-agents oriented by normative and cultural principles set out at the societal level, specifically within the urban area boundaries. In doing so, the analysis describes the key agents and their activities according to four different safety stages: Prevention, preparedness, response, and recovery. Institutional logics, distinguished as formal and informal, help to explain the behaviors and connections among agents. With the idea that a locally placed, organizational field reflects its peculiarity, we used four Italian towns located in two different areas of Campania, which live under the constant risk of a volcanic eruption, as examples. The results show how safety structures systems are contextual, characterized by locally embedded formal and informal rules, but not necessarily mutually aimed at orienting key agents to improve the safety performance. This contribution aims to support empirical analyses, natural experiments as well as qualitative studies to compare urban areas designed as safety-organizational fields from a multidisciplinary perspective. At the same time, we indicate some policy suggestions by emphasizing differences among organizational fields.

As different as night and day: Scaling analysis of Swedish urban areas and regional labor markets

The urban scaling framework views cities as integrated socioeconomic networks of interactions embedded in physical space. A crucial property of cities highlighted by this approach is that cities act to mix populations, a mixing both facilitated and constrained by physical infrastructure. Operationalizing a view of cities as settings for social interactions and population mixing—assembling a set of spatial units of analysis which contain the relevant social aspects of urban settlements—implies choices about the use of existing data, the assignation of data to locations, and the delineation of the boundaries of urban areas, all of which are far from trivial research decisions. Metropolitan areas have become the spatial unit of choice in urban economics and economic geography for investigating urban life as they are seen as encompassing the distinct phenomena of “urbanity” (proximity, density) and social interactions indirectly captured through a unified labor market. However, the population size and areal extent of metropolitan areas, as most often defined, render opaque the distinction between two salient types of urban population: those who work and those who reside within a metropolitan area. These two sets of individuals, among whom of course there is great overlap, putatively engage in different economic and social interactions which are in turn differently embedded in physical space. Availing ourselves of Swedish micro-level data for two distinct spatial units, tätorts (“dense localites”) and local labor markets, we can distinguish which types of populations and which types of spatial agglomerations are responsible for the observed scaling effects on productivity and physical infrastructure. We find that spatially contiguous labor markets are not enough to generate some of the most salient urban scaling phenomena.

Spatiotemporal patterns of urban sprawl and its relationship with economic development in China during 1990–2010

Given the fact that China has been experiencing rapid urbanization since the 1980s, limited empirical research has analyzed the spatial patterns of urban land expansion across Chinese cities using national data sets. This article attempts to explore evidence of urban sprawl and its relationship with levels of economic development using novel geospatial data on urban area boundaries and development densities for all Chinese cities. Different from existing studies, we used a decomposition approach to examine the differences between the 1990 urban boundaries and their newly developed suburbs (1990–2010) in population density and road intersection density, two key characteristics of urban sprawl. The main results show that Chinese cities have experienced dramatic increases in built-up areas but substantial decreases in development densities in the newly urbanized areas in comparison to their inner city counterparts, signifying concrete evidence of urban sprawl. Moreover, results from regression analyses indicate that a city's economic development level was positively related to urban land expansion after controlling for confounding factors, largely due to the nature of China's land-centered urbanization and economic development strategies. Findings from this article can help raise awareness about the staggering reality of urban land expansion across Chinese cities and urge urban planners and policymakers to tighten their rural-to-urban land conversion systems and curb urban sprawl.

Analyzing and Simulating Urban Density: Exploring the Difference Between Policy Ambitions and Actual Trends in the Netherlands

This chapter explores the potential of geospatial analysis to characterize land use dynamics in urban areas and the surrounding urban fringe. It focuses on the difference between policy ambitions and reality with respect to urban densification. Policy ambitions for the containment of urban development are ambitious in the Netherlands, as is evident from the many local objectives to concentrate residential development within existing urban areas. These ambitions are formulated as target shares of the total net increase in housing stock that should be realized within designated urban area boundaries. Following a GIS-based analysis of local changes in housing stock between 2000 and 2008, we are able to describe actual intensification shares and residential densities in newly-developed urban areas. We observe that, especially in the already densely-populated western part of the country, the realized urban intensification shares are below the specified policy goals/ambition levels. Using these observations along with scenario-based projections of the regional increases in housing stock, we are able to determine the demand for new urban land in 2020. Using a land use simulation model, we simulate the urban development processes until 2020 according to two scenarios and two policy alternatives. In the first policy alternative, growth in the number of house units is based upon policy ambitions, while in the second scenario growth is based upon observed trends over the past decade. The results show that current policy ambitions related to urban intensification levels will greatly help in containing the substantial urban growth that is projected in the case of a high economic and population growth scenario. If urban development follows past trends, unabated, thus demonstrating relatively low urban intensification shares, large-scale urban extensions are likely to occur.

Source data supported high resolution carbon emissions inventory for urban areas of the Beijing-Tianjin-Hebei region: Spatial patterns, decomposition and policy implications

This paper developed internationally compatible methods for delineating boundaries of urban areas in China. By integrating emission source data with existing official statistics as well as using rescaling methodology of data mapping for 1 km grid, the authors constructed high resolution emission gridded data in Beijing-Tianjin-Hebei (Jing-Jin-Ji) region in China for 2012. Comparisons between urban and non-urban areas of carbon emissions from industry, agriculture, household and transport exhibited regional disparities as well as sectoral differences. Except for the Hebei province, per capita total direct carbon emissions from urban extents in Beijing and Tianjin were both lower than provincial averages, indicating the climate benefit of urbanization, comparable to results from developed countries. Urban extents in the Hebei province were mainly industrial centers while those in Beijing and Tianjin were more service oriented. Further decomposition analysis revealed population to be a common major driver for increased carbon emissions but climate implications of urban design, economic productivity of land use, and carbon intensity of GDP were both cluster- and sector-specific. This study disapproves the one-size-fits-all solution for carbon mitigation but calls for down-scaled analysis of carbon emissions and formulation of localized carbon reduction strategies in the Jing-Jin-Ji as well as other regions in China.

Development of a thermal scheme for a cogeneration combined-cycle unit with an SVBR-100 reactor

At present, the prospects for development of district heating that can increase the effectiveness of nuclear power stations (NPS), cut down their payback period, and improve protection of the environment against harmful emissions are being examined in the nuclear power industry of Russia. It is noted that the efficiency of nuclear cogeneration power stations (NCPS) is drastically affected by the expenses for heat networks and heat losses during transportation of a heat carrier through them, since NPSs are usually located far away from urban area boundaries as required for radiation safety of the population. The prospects for using cogeneration power units with small or medium power reactors at NPSs, including combined-cycle units and their performance indices, are described. The developed thermal scheme of a cogeneration combined-cycle unit (CCU) with an SBVR-100 nuclear reactor (NCCU) is presented. This NCCU should use a GE 6FA gasturbine unit (GTU) and a steam-turbine unit (STU) with a two-stage district heating plant. Saturated steam from the nuclear reactor is superheated in a heat-recovery steam generator (HRSG) to 560–580°C so that a separator–superheater can be excluded from the thermal cycle of the turbine unit. In addition, supplemental fuel firing in HRSG is examined. NCCU effectiveness indices are given as a function of the ambient air temperature. Results of calculations of the thermal cycle performance under condensing operating conditions indicate that the gross electric efficiency ηel NCCUgr of = 48% and Nel NCCUgr = 345 MW can be achieved. This efficiency is at maximum for NCCU with an SVBR-100 reactor. The conclusion is made that the cost of NCCU installed kW should be estimated, and the issue associated with NCCUs siting with reference to urban area boundaries must be solved.

To the question of conditions, factors and criteria of geodynamic risk in the boundaries of urban areas

Formulation of the problem Loess deposits are widespread. They are characterized by the singular difficult deformations, therefore, their structure collapses. We have shown in the previous researches that in a zone of influence of the city properties of rocks change over time. Physical condition and gradation of microaggregates change over time as well. As a result, complex changes of physical properties occur. The duration of moistening affects the type and magnitude of the changes. Microaggregates do not disintegrate when the duration of moisture is short. When the duration of moisture is long, disintegration of the microaggregates is accompanied by the re-packaging and increasing of the endurance.The purpose of the article. The forecast of relative subsidence values and endurance can be performed using statistical analysis and group accounting method arguments. In this paper, we show the possibilities of forecasting using the example of a concrete construction site.Methods. Statistical method and the method of inductive modeling by group accounting of arguments were used in prognostic researches. In calculation of subsidence in the zone influences and stability analyses we used standard methods.Results. The object of research is an elementary natural and technical system formed by a projected building. The house will be built in the zone of distribution of loess’s (the erosion basin Vstrechnaya, Dnipro). The groundwater level in erosion basin is at a depth of 0.5 to 14.0 m. The magnitude of the increase of Groundwater level is 1.55 m from the modeling results in the research area. According to the results of multi-year data statistical analysis, close correlation relations between the property indices, regression between indicators of the physical state was found. The forecast values of mechanical properties' indicators are established as the results of inductive modeling with the method of group accounting of arguments. The forecast values of humidity and other indicators of the physical state, the content of individual fractions were set as well. The values were calculated to characterize a moderate and intensive change in soil properties in comparison with the natural state. Deformation calculations in the ground base and stability analysis were performed by standard analytical methods.Scientific novelty and practical significance. The following variants of events were considered: long-term or short-term humidification, complete or selective change in indicators of the physical condition of soils and microaggregate structure. The loss of strength is most likely to happen in case of emergency soaking of soils when the physical state changes but dispersion do not change.

Canadian urban tree canopy cover and carbon sequestration status and change 1990–2012

Urban trees provide numerous ecosystem goods and services by providing shade, habitat for wildlife, removal of air pollutants and the removal and storage of atmospheric CO2. Carbon removal services provided by Canadian urban trees have previously been assessed using an IPCC 2006 guidelines approach based on the percentage of urban area covered by tree canopy (UTC) for the 2012 time period (Pasher et al., 2014). That work however provided only a single point in time assessment of the national scale UTC and carbon removal services. The research undertaken for this study was a continuation of this earlier work focusing on a 1990 national scale UTC assessment and carbon sequestration estimates for 1990. UTC estimates for 1990 were developed using a point sampling approach with circa 1990 air photos covering a large portion of Canadian urban areas. In total almost 179,000 points were sampled for the 1990 time period, reassessing 83% of the points used for the previous 2012 assessment. Based on the urban area boundary layers for 1991 and 2011, Canada’s urban areas grew by an estimated 6% for this time period. Most of this growth occurred through conversion of agricultural and forested lands to urban. At the national scale the UTC for 1990 was estimated to be 27.6%, as compared to the 2012 UTC estimate of 26.1%, the difference between estimates for the two time periods fell within the uncertainty range. Carbon removal estimates based on the UTC estimates were also very similar for the two dates with 660.2 kt C removed in 1990 and 662.8 kt C removed in 2012. It was noted that urban development in the Prairie regions resulted in an increase in tree cover as compared to the pre-conversion agricultural and natural landscapes and also that in most urban areas across the country UTC increases through time as tree cover matured in newly developed urban areas. These two assessments provide a time series of urban trees for 22 year time period, which will be useful for further studies and analysis.

Detecting the Boundaries of Urban Areas in India: A Dataset for Pixel-Based Image Classification in Google Earth Engine

Urbanization often occurs in an unplanned and uneven manner, resulting in profound changes in patterns of land cover and land use. Understanding these changes is fundamental for devising environmentally responsible approaches to economic development in the rapidly urbanizing countries of the emerging world. One indicator of urbanization is built-up land cover that can be detected and quantified at scale using satellite imagery and cloud-based computational platforms. This process requires reliable and comprehensive ground-truth data for supervised classification and for validation of classification products. We present a new dataset for India, consisting of 21,030 polygons from across the country that were manually classified as “built-up” or “not built-up,” which we use for supervised image classification and detection of urban areas. As a large and geographically diverse country that has been undergoing an urban transition, India represents an ideal context to develop and test approaches for the detection of features related to urbanization. We perform the analysis in Google Earth Engine (GEE) using three types of classifiers, based on imagery from Landsat 7 and Landsat 8 as inputs. The methodology produces high-quality maps of built-up areas across space and time. Although the dataset can facilitate supervised image classification in any platform, we highlight its potential use in GEE for temporal large-scale analysis of the urbanization process. Our methodology can easily be applied to other countries and regions.

Quantifying the Impact of Different Ways to Delimit Study Areas on the Assessment of Species Diversity of an Urban Forest

Assessing the species diversity of an urban forest is important for understanding its structure and functions, but the result can be affected by sampling methods, times, and delimitations of the study area. In this study, we examined the influence of different ways to delimit boundaries of urban areas on the assessment of species diversity of urban forests through a case study conducted in Haikou, China. We surveyed the species diversity of the urban forest in Haikou twice using the same sampling protocol but two commonly used delimitations of the urban area. The two surveys produced significantly different estimates of species richness of the urban forest. Recorded species richness was 228 (144 woody and 84 herbaceous species) and 303 (164 woody and 139 herbaceous species) for the first and the second survey, respectively. The rarefaction analysis indicated that species richness of woody plants recorded in the two surveys could converge by doubling the sample size, but species richness of herbaceous plants was significantly different between the two surveys at the 95% confidence interval even at three times the original sample size. The value of the Simpson dissimilarity index between the two surveys was 0.417 and 0.357 for woody and herbaceous plants respectively, which implied noticeable dissimilarity of species compositions of plant assemblages in the two areas. We concluded that the assessment of biodiversity of an urban forest can be affected significantly by how the boundary of an urban area is defined. Caution should be taken when comparing species diversities of urban forests reported in different studies, especially when richness measures are used.

LEGAL REGULATION OF THE ESTABLISHMENT (ALTERATION) OF THE SETTLEMENTS’ BOUNDARIES IN UKRAINE: PROBLEMS AND WAYS OF THEIR SOLUTION

The article deals with the issues of legal regulation of the establishment (alteration) of the settlements’ boundaries in Ukraine. The contemporary issues regarding the establishment (alteration) of the Ukrainian settlements’ boundaries are analyzed; the author makes his own proposals as to their solution. The author pays specific attention to the fact that in Ukraine most of the settlements boundaries’ were established a long time ago, particularly, in the last century. Since then the area of the settlements’ lands has significantly increased. This requires adoption of the local decisions connected with changing of the boundaries of the large number of settlements. The main issues in establishment (alteration) of the settlements’ boundaries include the following : – absence of the inified law on administrative-territorial structure of Ukraine; – absence of master plans in many cities under which the establishment of settlements’ boundaries is conducted; – insufficient level of financial funding for establishing of settlements’ boundaries; – reluctance of local governments to settle issues of establishing and changing of settlements’ boundaries. The conclusion about the need for compensation to local authorities whose territory is reduced by expanding the boundaries of urban areas was made by the author. Replacement of the category of lands of settlements on lands of residential and public buildings was considered to be unsuccessful. This led to a change in the concept of «settlement boundary» and its legal significance. The author concludes that the dependence of formation of settlements’ boundaries from the development of master plans should be eliminated. The suggestion for improving of the legislation of Ukraine on establishing the settlements’ boundaries is made by the author. It is necessary to adopt the specialized law on administrative-territorial structure of Ukraine, amend the Land Code of Ukraine and other legal acts.

THE POTENTIALS OF SATELLITE IMAGES FOR MAP UPDATING WITH EMPHASIZES ON EGYPT SAT-1 IMAGES

The lack of adequate maps is one of the critical issues to be handled in developing countries. The main problem is the rapid development of urban areas, so that maps are out of date very fast. Consequently, nearly all these maps have to be revised and updated as soon as possible. Recently, due to the improvement in satellite technology, remote sensing data is applied for mapping and map updating at different scales. On April 17, 2007 the first Egyptian earth observation satellite Egypt Sat-1 was launched. The available images from Egypt Sat-1 satellite provides valuable source of remote sensing data in Egypt. This paper aims to evaluate the potential of Egypt Sat-1 images versus other satellite images for maps updating. Data used in this study are satellite images from Egypt Sat-1, SPOT 4, IKONOS and topographic map at scale 1:25,000. The methodology focuses on visual comparison of the images over the test area for specific features such as roads, railways, watercourses and boundaries of urban areas. After that an investigation is carried out for the potential of the information content in Egypt Sat-1 images, for updating 1:25,000 map. The results of these evaluations show that Egypt Sat-1 images, from the point of geometric accuracy, have the capability of 1:25,000 scale maps revision. Also, from the point of information content, it have the capability of revision of the main features such as building blocks, roads and vegetation cover. Revision of other objects in Egyptian 1:25,000 scale maps that are problematic in their identification and extraction from Egypt Sat-1 images can be completed using other mapping methods.

EVALUATION OF INFORMATION CONTENT AND FEATURE EXTRACTION CAPABILITY FROM EGYPT SAT 1 IMAGE

Maps are fast and accurate information sources when it is required, tostudy and to develop projects in any region. In Egypt, many of theavailable maps are in an unsatisfactory scale and not updated. Theavailability of Egypt Sat1 satellite images, opened new possibilities formapping and map updating. Egypt Sat1 is the first Egyptian earthobservation satellite which was successfully put in orbit in 2007. Itcaptures both multi-spectral and panchromatic images with resolution of7.8 meters. The main objective of this study is to evaluate the potentialsof information content in Egypt Sat1 images for extracting features inthe context of updating of 1:25,000 topographic maps and to ascertainwhat features could be identified and mapped using visual interpretationtechniques supported by supplementary data.Data used in this study are an image from Egypt Sat1satellite capturedin 2009 and a topographic map, dated 1991, at scale 1:25,000 of theregion of Assiut city and the surrounding. The investigation in EgyptSat1 data focused on identification of urban features such as roads,railways, watercourses, bridges and boundaries of urban areas. ERDASimagine 9.2 software was utilized, where qualitative and quantitativeevaluations were performed for the informative content. The researchresults point to the potential of Egypt Sat1 images as a low costalternative data source with field verification for the updating oftopographic maps at scale 1:25,000.

Incorporating Geographic Information Systems (GIS) into Program Evaluation: Lessons from a Rural Medicine Initiative

To address the shortage of physicians practicing in rural areas of Michigan, the Wayne State University School of Medicine developed an integrated rural core curriculum to interest students in rural practice careers. Here we focus on the evaluation strategy used to determine the extent to which students in the new rural medicine interest group who self-identified as selecting a rural clerkship or externship did secure a clinical training experience in a rural setting. Three measures of rurality were compared to determine whether students were placed in rural training settings: (1) the percentage of the county living in rural areas; (2) a county-level dichotomous measure of rural/nonrural; and (3) a dichotomous measure based on urban area boundaries within the county. Practice address and geographic data were integrated into geographic information systems software, which we used to map out rural characteristics of Michigan counties through a process called thematic mapping; this shows characteristic variation by color-shading geographic features. In addition, reference maps were created showing the boundaries of urban areas and metropolitan/micropolitan areas. Once these processes were completed, we overlaid the practice location on the contextual-level geographic features to produce a visual representation of the relationship between student placement and rural areas throughout the state. The outcome of student placement in rural practices varied by the definition of rural. We concluded that, although students were not placed in the most rural areas of Michigan, they received clerkship or externship training near rural areas or in semirural areas. This process evaluation had a direct impact on program management by highlighting gaps in preceptor recruitment. A greater effort is being made to recruit physicians for more rural areas of the state rather than urban and semirural areas. Geographic information systems mapping also defined levels of ruralism for students to help them make informed selections of training sties. This is especially important for students who are not sure about a rural experience and might be discouraged by placement in a remote rural area.

Urban-Area and Building Detection Using SIFT Keypoints and Graph Theory

Very high resolution satellite images provide valuable information to researchers. Among these, urban-area boundaries and building locations play crucial roles. For a human expert, manually extracting this valuable information is tedious. One possible solution to extract this information is using automated techniques. Unfortunately, the solution is not straightforward if standard image processing and pattern recognition techniques are used. Therefore, to detect the urban area and buildings in satellite images, we propose the use of scale invariant feature transform (SIFT) and graph theoretical tools. SIFT keypoints are powerful in detecting objects under various imaging conditions. However, SIFT is not sufficient for detecting urban areas and buildings alone. Therefore, we formalize the problem in terms of graph theory. In forming the graph, we represent each keypoint as a vertex of the graph. The unary and binary relationships between these vertices (such as spatial distance and intensity values) lead to the edges of the graph. Based on this formalism, we extract the urban area using a novel multiple subgraph matching method. Then, we extract separate buildings in the urban area using a novel graph cut method. We form a diverse and representative test set using panchromatic 1-m-resolution Ikonos imagery. By extensive testings, we report very promising results on automatically detecting urban areas and buildings.

Freeway Speed Zones: Safety and Compliance Issues

The effectiveness and appropriateness of establishing speed limits on freeways and the spatial extent of the zones were studied. Of particular interest were 55-mph (88-km/hr) speed zones that exist in the transition between urban and rural areas (determined according to urban area boundaries). Three types of freeway segments (urban-55, fringe-55, and rural-65) were analyzed, and although the study was of comparatively small scale, the results generally showed that higher speeds do not lead to more numerous or serious accidents. Moreover, compliance with speed limits is not necessarily a good measure of safety. On the other hand, motorists are self-policing to a certain degree in that they drive at reasonable speeds given the design of the different types of freeways. It is suggested that artificially lowered speed limits without a clear need being established from engineering and safety perspectives will not yield impressive safety benefits.