Urbanisation produces numerous changes in the natural environments it replaces. The impacts include habitat fragmentation and changes to both the quality and quantity of the stormwater runoff, and ...result in changes to hydrological systems. This review integrates research in relatively diverse areas to examine how the impacts of urban imperviousness on hydrological systems can be quantified and modelled. It examines the nature of reported impacts of urbanisation on hydrological systems over four decades, including the effects of changes in imperviousness within catchments, and some inconsistencies in studies of the impacts of urbanisation. The distribution of imperviousness within urban areas is important in understanding the impacts of urbanisation and quantification requires detailed characterisation of urban areas. As a result most mapping of urban areas uses remote sensing techniques and this review examines a range of techniques using medium and high resolution imagery, including spectral unmixing. The third section examines the ways in which scientists and hydrological and environmental engineers model and quantify water flows in urban areas, the nature of hydrological models and methods for their calibration. The final section examines additional factors which influence the impact of impervious surfaces and some uncertainties that exist in current knowledge.
In urban areas, spectral mixture analysis (SMA) is a common technique for deriving the fractions of land covers within a pixel and information on the distribution of impervious surfaces. This study ...examined how the selection of endmembers affected the quantification of impervious surfaces using TM and ASTER imagery. Multiple subsets of endmembers derived using (1) extreme pixels from a minimum noise fraction (MNF) transformation, and (2) a manual approach using a priori knowledge of the study area were analysed. Two data sets were used to assess accuracy: (1) simulated image data comprising unmixed and mixed pixels of 10 typical and spectrally different urban land covers, and (2) detailed data derived from high-resolution aerial photography. The dimensionality of the imagery limited the number of endmembers, and as a result, unmixed land covers were modelled using multiple endmembers and some cells had abundance values that summed to more than one or were negative. The land covers of red roofs and concrete were the largest contributors to the error in impervious surfaces. The Sequential Maximum Angle Convex Cone (SMACC) endmember model was also used to unmix the images; however, the larger number of endmembers did not resolve the use of multiple endmembers to model the unmixed land covers and the accuracy was similar to that using SMA. The relationship between the pervious fraction estimated using the vegetation endmember and the ground reference data was stronger than that for the impervious fraction, although the fraction was underestimated. The problems in modelling highly variable impervious surfaces with a limited number of endmembers suggest that in urban environments with substantial vegetation, modelling the vegetation component as the inverse of the impervious fraction may lead to improved results.
This study analyzed the geographical patterns of heat-related mortality among the population aged 65 and over within the metropolitan area of Sydney, Australia between 1993 and 2004, and evaluated ...the role of some physical and socio-demographic risk factors associated with it. The effect of temperature on all-cause mortality during unusually hot days was investigated using spatial analytic techniques, such as cluster analysis and spatial regression analysis. Generalized Linear Models (GLMs) were used to investigate the role of daily average temperature, ozone (O
3) and particulate matter of diameter less than 10
μm (PM
10) at the regions that showed a significant increase in mortality on unusually hot days.
Spatial variation in mortality on unusually hot days was observed among the population 65 and over. Elderly people living within 5–20
km south-west and west of the Sydney Central Business District (CBD) were found to be more vulnerable. However, analysis using GLMs showed temperature to be a significant modifier of daily mortality in the region to the south-west of the CBD only. O
3 and PM
10 were found to be non-significant factors in the regions where air pollutants were studied. Socio-economic status and the proportion of vegetation or developed land in each Statistical Local Area (SLA) were also not a significant factor explaining the increased mortality. A combination of social and environmental factors may be at play. Our results suggest an effect of temperature on mortality of the elderly population in Sydney Statistical Division at the SLA level. More spatially-based research would be beneficial once climate datasets with improved spatial coverage become available.
This study examined an area of woodland that was recovering from severe fire in Royal National Park (NSW, Australia). A non-destructive method of field sampling is required for vulnerable recovering ...vegetation and therefore classification of digital photographs using linguistic terms was trialled. The linguistic data for three vegetation strata (canopy, shrub and ground) were converted to crisp scores and compared with vegetation index data derived from remotely sensed imagery. All possible subset regression was used to test the proposition that the combined vegetation scores (independent variables) would explain the values of NDVI (Normalized Difference Vegetation Index) and NDMI (Normalized Difference Moisture Index). Vegetation scores for the three strata were also combined using simplified weighting ratios to assess broad relationships between the indices and field data. The combined vegetation scores explained ~60% of the variation in the vegetation index data and inclusion of variables representing multiple strata explained more of the variation than any single variable. The precise value of the weights used to combine the layers did not affect the strength of the association. A simple ratio is proposed that may be useful to estimate woodland parameters under similar conditions, by inversion of the relationship with vegetation index data.
This study investigates the effect that membership in a financial keiretsu has on the export performance of Japanese manufacturing companies. Companies that belong to one of the six major financial ...keiretsu are found to have lower export ratios than similar companies who are not members. The negative effects of keiretsu membership appear confined to producer goods companies where intergroup linkages such as preferential trading relationships are tightest. Additional evidence from the producer goods sector showing that keiretsu members do less well on other measures of company performance supports the argument that the cartel-like properties sometimes ascribed to the keiretsu actually reduce competitiveness, thus dampening export performance. In general, the data do not support recommendations that non-Japanese companies might look to keiretsu-type alliances as an organizational strategy that will lead to competitive advantage in global markets.
This study uses GIS techniques to examine the spatial distribution of stream power along major streamlines in the Lane Cove catchment in northern Sydney, Australia. Channel gradient estimates derived ...from a 5 m resolution digital elevation model (DEM) are combined with streamflow data to estimate stream power along river courses. Stream power and its constituent components are then related to a detailed field‐based assessment of sediment storage along the trunk stream and primary tributaries. At the catchment scale, sediment storage per unit length decreases as channel gradient and gross stream power increase. However, local controls such as variability in valley width and occurrence of confluence zones exert a greater influence upon sediment storage, disrupting systematic catchment‐wide relationships. The total volume of storage along each streamline has a strong linear relationship to the area of the subcatchment, but the distribution of sediment along streamlines varies between subcatchments. The GIS framework employed in this project allows generation of continuous, empirical data, thereby providing catchment‐specific predictive capacity that can accompany theoretical approaches to stream power modelling.
This study investigates the proposition that Japanese companies have a greater propensity than U.S. companies to sustain commitment to R&D in the face of fluctuating profits and liquidity. The ...analysis showed that profitability declines led to increased R&D intensity in Japan. These effects were not confined to members of Japanese financial keiretsu, or industrial groups. The R&D intensity of U.S. companies fluctuated directly with two-year lagged profitability and liquidity variables, but these relationships might have been confined to more research-intensive companies.
Purpose - The purpose of this research is to analyze and compares principal factors that contribute to successful public-private partnerships and public works projects.Design methodology approach - ...This study uses a qualitative analysis with in-depth interviews and observation. Interviews are conducted with key individuals of two projects. Success factors are derived from literature review and modified through in-depth interviews and comparative analysis.Findings - Ten success factors are presented and analyzed: specific plan vision, commitment, open communication and trust, willingness to compromise collaborate, respect, community outreach, political support, expert advice and review, risk awareness, and clear roles and responsibilities. High degrees of commitment and shared vision between the client, architect, and contractor are shown to be important aspects for construction success as well as pairing factors of open communication and trust with high levels of compromise or collaboration.Research limitations implications - The major limitation of this research is that it is confined to two case studies. Thus, the generalizability can be utilized for future reference. Further research might review various types of partnerships, such as design-build relationships, construction manager at risk, or team-building partnering for projects that may be blocked from the public sector, or public works development.Originality value - This study proposes two matrix frameworks to explore a more complete review of relationships of paired success factors. The frameworks view the interplay of how different combined levels or degrees of corresponding factors such as commitment and shared vision can help make a project more effective. These matrices create unique views of comparative factors developed as part of this research paper, which could be further investigated in future research.
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