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81.
Jill D. Humphreys Glenn Porter Michael Bell 《Forensic Science International Supplement Series》2008,178(1):46-53
Research into fingermark enhancement techniques has traditionally used visual comparisons and qualitative methods to assess their effectiveness based on the quality of the developed fingermark. However, with increasing research into the optimisation of these techniques the need for a quantitative evaluative method has arisen. Parameters for acceptable fingerprint quality are not well defined and generally encompass clear, sharp edges and high levels of contrast between the fingermark ridges and background material. Using these current parameters, a conclusive measurement of fingerprint quality and thus the effectiveness of development techniques cannot be achieved.This study presents a model through which an aspect of fingerprint quality can be objectively and impartially measured based on a relative contrast index, constructed through measuring the reflective intensity of the fingermark ridges against the background material. Using a fibre-optic spectrophotometer attached to a microscope with axial illumination, the intensity counts of the ridge detail and background material were measured and a logarithmic contrast index constructed. The microscope and spectrophotometer parameters were experimentally tested using a standard colour resolution chart with known reflective properties. The protocol was successfully applied to four sample groups: black inked fingerprints on white paper; latent fingermarks on white paper developed separately with ninhydrin and physical developer; and fingermarks in blood deposited on white tiles and enhanced with amido black. The contrast indices obtained quantitatively reflect the level of contrast and provide an indication of fingerprint quality through a numerical representation rather than previous qualitative methods. It has been suggested that the proposed method of fingerprint quantification may be viable for application in the forensic research arena as it allows the definitive measurement of contrast to aid the evaluation of fingermark detection and enhancement techniques. 相似文献
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Negotiation Journal - 相似文献
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Frederick W. Bell 《政策研究评论》1986,6(2):374-381
Coastal beaches are a source of considerable recreational activity, but are also eroding at a rapid rate. Since beach resources are common property, there is no organized market to determine economic benefits from recreational use. Through a willingness to pay equation for beach use, this article demonstrates how proposed beach renourishment policy can be evaluated within a benefit-cost analysis framework. Benefits are estimated as the incremental willingness to pay per day for a larger beach width which is translated into annualized benefits. Annualize cost of achieving maximum benefits are calculated from a cost function. Given the existing cost of beach renourishment, it was found that all beaches in Florida that are overcrowded (i.e., had less than 112 square feet per person/day) could be renourished at a benefit-cost ratio greater than unity. In Florida, beach renourishment policy for overcrowded beaches yields more economic benefits than costs. However, this technique does not lend itself to policy analyses of uncrowded beaches that are undergoing considerable erosion. 相似文献
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Alexander Pope Alison K. Cohen Catherine d.P. Duarte 《Journal of Public Affairs (14723891)》2019,19(1)
This paper explores the connections between education for youth civic engagement and theories and strategies from public health (specifically, epidemiology). We illustrate this with four applications of epidemiologic theory to youth civic engagement: social determinants and fundamental causes, vulnerable populations and cumulative disadvantage, positive spillover, and herd immunity and critical mass. Formalizing concepts of current civics, in schools and the public, as a civic epidemic, we present a case for individual‐ and group‐level interventions based around targeted, school‐based, effective civic education initiatives. Grounded in epidemiological theory, such approaches call attention to the simultaneous need to improve broad civics education and ensure that particular populations receive necessary attentions. 相似文献
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