Botswana water and surface energy balance research program. Part 1: Integrated approach and field campaign results

The Botswana water and surface energy balance research program was developed to study and evaluate the integrated use of multispectral satellite remote sensing for monitoring the hydrological status of the Earth's surface. Results of the first part of the program (Botswana 1) which ran from 1 Jan. 1988 - 31 Dec. 1990 are summarized. Botswana 1 consisted of two major, mutually related components: a surface energy balance modeling component, built around an extensive field campaign; and a passive microwave research component which consisted of a retrospective study of large scale moisture conditions and Nimbus scanning multichannel microwave radiometer microwave signatures. The integrated approach of both components in general are described and activities performed during the surface energy modeling component including the extensive field campaign are summarized. The results of the passive microwave component are summarized. The key of the field campaign was a multilevel approach, whereby measurements by various similar sensors were made at several altitudes and resolution. Data collection was performed at two adjacent sites of contrasting surface character. The following measurements were made: micrometeorological measurements, surface temperatures, soil temperatures, soil moisture, vegetation (leaf area index and biomass), satellite data, aircraft data, atmospheric soundings, stomatal resistance, and surface emissivity

Zero Knowledge Watermark Detection

. In order for digital watermarking technology to be truly usable, one must be able to employ it without annihilating its effect. The act of revealing a watermark within an object, in order to prove ownership or detect theft of said object, may open the door to subsequent theft, by providing attackers with the information they need to remove the watermark. The idea of zero-knowledge watermarking, of proving the existence of a mark without revealing what that mark is, can help address this problem and others. 1 Introduction 1.1 The Problem Digital watermarking has been proposed as a solution to a number of media security problems. Robust digital watermarks, designed to survive within a media object unless an unreasonable amount of damage has been inflicted upon it, or unless an unreasonable amount of time is spent; have been aimed at both theft detection (i.e., Digimarc's MarcSpider service) and at resolving ownership in a court of law. Fragile watermarks, such as described in..