3 resultados para Long Point Company
em University of Washington
Resumo:
Thesis (Master's)--University of Washington, 2016-06
Resumo:
A method is presented for accurate measurement of spectral flux-reflectance (albedo) in a laboratory, for media with long optical path lengths, such as snow and ice. The approach uses an acrylic hemispheric dome, which, when placed over the surface being studied, serves two functions: (i) it creates an overcast “sky” to illuminate the target surface from all directions within a hemisphere, and (ii) serves as a platform for measuring incident and backscattered spectral radiances, which can be integrated to obtain fluxes. The fluxes are relative measurements and because their ratio is used to determine flux-reflectance, no absolute radiometric calibrations are required. The dome and surface must meet minimum size requirements based on the scattering properties of the surface. This technique is suited for media with long photon path lengths since the backscattered illumination is collected over a large enough area to include photons that reemerge from the domain far from their point of entry because of multiple scattering and small absorption. Comparison between field and laboratory albedo of a portable test surface demonstrates the viability of this method.
Resumo:
Classification schemes are built at a particular point in time; at inception, they reflect a worldview indicative of that time. This is their strength, but results in potential weak- nesses as worldviews change. For example, if a scheme of mathematics is not updated even though the state of the art has changed, then it is not a very useful scheme to users for the purposes of information retrieval. However, change in schemes is a good thing. Changing allows designers of schemes to update their model and serves as a responsible mediator between resources and users. But change does come at a cost. In the print world, we revise universal clas- sification schemes—sometimes in drastic ways—and this means that over time, the power of a classification scheme to collocate is compromised if we do not account for scheme change in the organization of affected physical resources. If we understand this phenomenon in the print world, we can design ameliorations for the digital world.