396 research outputs found

    Improvement of PolSAR Decomposition Scattering Powers Using a Relative Decorrelation Measure

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    In this letter, a methodology is proposed to improve the scattering powers obtained from model-based decomposition using Polarimetric Synthetic Aperture Radar (PolSAR) data. The novelty of this approach lies in utilizing the intrinsic information in the off-diagonal elements of the 3×\times3 coherency matrix T\mathbf{T} represented in the form of complex correlation coefficients. Two complex correlation coefficients are computed between co-polarization and cross-polarization components of the Pauli scattering vector. The difference between modulus of complex correlation coefficients corresponding to Topt\mathbf{T}^{\mathrm{opt}} (i.e. the degree of polarization (DOP) optimized coherency matrix), and T\mathbf{T} (original) matrices is obtained. Then a suitable scaling is performed using fractions \emph{i.e.,} (Tiiopt/i=13Tiiopt)(T_{ii}^{\mathrm{opt}}/\sum\limits_{i=1}^{3}T_{ii}^{\mathrm{opt}}) obtained from the diagonal elements of the Topt\mathbf{T}^{\mathrm{opt}} matrix. Thereafter, these new quantities are used in modifying the Yamaguchi 4-component scattering powers obtained from Topt\mathbf{T}^{\mathrm{opt}}. To corroborate the fact that these quantities have physical relevance, a quantitative analysis of these for the L-band AIRSAR San Francisco and the L-band Kyoto images is illustrated. Finally, the scattering powers obtained from the proposed methodology are compared with the corresponding powers obtained from the Yamaguchi \emph{et. al.,} 4-component (Y4O) decomposition and the Yamaguchi \emph{et. al.,} 4-component Rotated (Y4R) decomposition for the same data sets. The proportion of negative power pixels is also computed. The results show an improvement on all these attributes by using the proposed methodology.Comment: Accepted for publication in Remote Sensing Letter

    Developmental research of sustainable technologies to minimise problematic road embankment settlements

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    Challenging, problematic and non-uniform ground conditions are a night mare to geotechnical engineers tasked with the design and construction of buildings and transport infrastructure. These often suffer undesirable structural settlements. Designing within the current understanding of geotechnics; settlement in peat and organic soils need to be recognised to include the known “primary and secondary consolidation characteristics” and the lesser known “tertiary consolidation phase”. These eventually contribute cumulatively to the consequential uneven and hazardous “bumpy road” surfaces. Undulating flexible road pavements result primarily from the transference of the heavy self-weight of the embankment fill to yielding and non-uniform subgrade. The adoption of conventional design/repair methods such as pile, vertical drain, soil replacement and soil stabilisation are expensive and inappropriate in very soft ground conditions. These then lead to unjustifiably high and repetitive maintenance costs. There being no one quick fix solution for all; pragmatic research must necessarily identify the best/progressively improved practical and sustainable solution. A viable solution is to develop criteria and explore the concept of a “masonry arch bridge structure/lintel-column structure” and adopting sustainable materials through pragmatic searching for appropriate recyclable waste materials. This will lead to the basis for a sustainable, innovative, strong, stiff, permeable composite mat structure that can be used on soft and/or yielding ground conditions. Conceptual lightweight fill technology including the popularly used expanded polystyrene (EPS) and the innovative composite mats recently being developed by the research team are outlined

    Private Fingerprint Verification without Local Storage

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    A Formal Study of the Privacy Concerns in Biometric-Based Remote Authentication Schemes

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    With their increasing popularity in cryptosystems, biometrics have attracted more and more attention from the information security community. However, how to handle the relevant privacy concerns remains to be troublesome. In this paper, we propose a novel security model to formalize the privacy concerns in biometric-based remote authentication schemes. Our security model covers a number of practical privacy concerns such as identity privacy and transaction anonymity, which have not been formally considered in the literature. In addition, we propose a general biometric-based remote authentication scheme and prove its security in our security model

    Effects of the current financial and economic crisis on the rural landscape as well as the agri-food sector in Europe and Central Asia

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    This paper reviews the expected effects of the current financial crisis and subsequent recession on the rural landscape, in particular the agri-food sector in Europe and Central Asia (ECA) on the basis of the structure of the rural economy and of different organisations and institutions. Empirical evidence suggests that the crisis has hit the ECA region the hardest. Agriculture contributes about 9% to gross domestic product (GDP) for the ECA region as a whole with 16% of the population being employed in the agricultural sector. As far as the impact of the financial crisis on the agri-food sector is concerned, there are a few interconnected issues: (1) reduction in income elastic food demand and commodity price decline, (2) loss of employment and earnings of rural people working in urban centres, implying also costly labour reallocation, (3) rising rural poverty originating mainly from lack of opportunities in the non-farm sector and a sizable decline of international remittances, (4) tightening of agricultural credit markets, and the (5) collapse of sectoral government support programs and social safety-net measures in many countries. The paper reveals how the crisis hit farming and broader agri-business differently in general and in the ECA sub-regions

    Finance, Development, and Remittances: Extending the Scale of Accumulation in Migrant Labour Regimes

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    The last decade has seen a heightened level of interest in the relationship between remittances and development, driven by the World Bank and other Bretton Woods Institutions. This has materialised in a global agenda to incorporate migrants and their households in commercial banking. The double significance of this policy rests in the financial incorporation of migrants and their households, and in the deepening entrenchment of the historical labour migration dynamic between sending communities and centres of capital. The central role of labour power in the advance of money forms the core of this analysis of a contemporary market-building strategy. This article presents a threefold critique of the global remittance agenda, based on (1) its transformative profit-driven development ideology, (2) its detachment of remittances from the political economy of migrant labour regimes, and (3) its dismissal of existing modes of remitting and uses of the funds

    Impact of remittances on economic growth in developing countries: The role of openness

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    The paper examines the empirical relationship between remittances and economic growth for a sample of 62 developing countries over the time period 1990–2014. Remittances seem to promote growth only in the ‘more open’ countries. That is because remittances are in themselves not sufficient for growth. The extent of the benefit depends on domestic institutions and macroeconomic environment in the receiving country. Unlike the ‘less open’ countries, ‘more open’ countries have better institutions and better financial markets to take advantage of the remittances income and channelise them into profitable investments which, in turn, accelerates the rate of economic growth in these countries.N/
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