Estimating woody browse abundance from aerial imagery

In the deciduous forests of the eastern US, timber harvest programmes are often designed to increase the availability of woody browse for terrestrial wildlife. However, assessing the efficacy of timber harvest at increasingly available browse has traditionally required labour‐intensive field‐based measurements of woody plant growth and abundance. The objective of this study was to use readily available digital aerial imagery to estimate the amount of woody browse in regenerating clearcuts in central West Virginia. Aerial imagery from the National Agriculture Imagery Program and woody browse data collected from 11 regenerating clearcuts in the summer of 2007 were used in this analysis. Red, green and blue visible bands, as well as a simple texture metric, were used to create a multiple linear regression model to predict the amount of woody browse. The final model exhibited large correlation (R ² = 0.94) and was statistically significant (F = 22.48, p = 0.0009), indicating that simple measures of image digital numbers and texture have potential utility in assisting forest and wildlife managers to assess habitat quality in forest regeneration areas.     

Enhancing the US Navy's GIDB Portal with Web Services

Using Web services, the authors have been able to increase the amount of data accessible through the Naval Research Laboratory’s Geospatial Information Database (GIDB) portal. They created a Web crawler for Web Mapping Services (WMS) that harvests and adds data to the portal index and a translator that provides access to non-WMS data through the WMS interface. The Integrated Web Services Broker, using traditional Web services standards, provides automated access to meteorological and oceanographic data.     

Electrochemical detection of peptides

A general method of wide applicability for the determination of peptides is described. Peptides longer than dipeptides react in the classical biuret reaction with Cu(II) to yield electroactive Cu(II)-peptide complexes that can be oxidized to the corresponding Cu(III) complexes. This allows the sensitive electrochemical detection of peptides following their separation by reversed-phase liquid chromatography. The reaction chemistry, which is reversible, allows for the determination of peptides that lack an electroactive group or a primary amine. Selectivity for a model peptide is 10(3)-10(4) over nonelectroactive amino acids.     

State Estimation For An Agonistic‐Antagonistic Muscle System

Research on assistive technology, rehabilitation, and prosthetics requires the understanding of human machine interaction, in which human muscular properties play a pivotal role. This paper studies a nonlinear agonistic‐antagonistic muscle system based on the Hill muscle model. To investigate the characteristics of the muscle model, the problem of estimating the state variables and activation signals of the dual muscle system is considered. In this work, parameter uncertainty and unknown inputs are taken into account for the estimation problem. Three observers are presented: a high gain observer, a sliding mode observer, and an adaptive sliding mode observer. Theoretical analysis shows the convergence of the three observers. Numerical simulations reveal that the three observers are comparable and provide reliable estimates.     

Determination of platinum in blood by adsorptive voltammetry

This work describes a sensitive method for the determination of platinum in blood, which can be used for determining the natural levels of platinum in human blood, for monitoring patients treated with platinum cytotoxic drugs, and for monitoring occupational exposure to these drugs and other platinum compounds. The method involves dry ashing of blood samples in a muffle furnace and determination of platinum by adsorptive voltammetric (AV) measurement of the catalytic reduction of protons by the platinum-formazone complex. The detection limit for a 100-microL sample of blood is 0.017 micrograms/L, with a recovery of 94% and a relative standard deviation of 7% at a platinum level of 1 microgram/L. By using this method, the natural levels of platinum in human blood were found to be in the range 0.1-2.8 micrograms/L (median = 0.6 micrograms/L). These results were verified by inductively coupled plasma mass spectrometry (ICP-MS) with blood prepared by wet ashing and using gold as an internal standard.     

DES-GENERATED CHECKSUMS FOR ELECTRONIC SIGNATURES

Secrecy and authentication are two important features of a secure communication system. Public Key Cryptosystems, based, e.g., on the Rivest-Shamir-Adleman (RSA) algorithm, provide a very elegant solution to the problem of authenticity verification or true electronic signatures. Practical problems, however, mainly the lack of execution speed, prevent a straightforward application. In order to sign a long message it is much faster to first calculate a short digest or checksum and then sign the compressed message. For this checksum calculation the fast, inexpensive and extensively tested Data Encryption Standard (DES) can be used. But care must be taken that this additional processing step does not introduce any weakness into the signature scheme. This paper investigates two DES-based hashing methods. It is shown that neither method seems to introduce any statistical regularities in the generated checksums. The “Cipher/Message to Plain Feedback,” however, is not secure under a modification compensation attack. It is further shown how the second method, the “Cipher to Plain Feedback” proposed by Davies and Price, can be broken by a “meet in the middle attack.” This checksum method, however, can be used safely with a slight modification.     

Comparison of atmospheric modelling versus empirical line fitting for mosaicking HYDICE imagery

This letter compares two approaches for determining surface reflectance from hyperspectral airborne imagery (HYDICE) radiance values, and discusses the implications for mosaicking multiple flight lines of HYDICE imagery. Empirical line correction, using calibration panels followed by histogram matching to an adjacent image, produced results comparable with that obtained from applying the ATREM model (Gao et al. 1993, Remote Sensing of Environment, 44, 165-178) to the two flight lines individually. Percentage errors were greatest for low albedo materials and for the long wavelength portions of the spectra. Overall, differences in reflectance values between adjacent frames of 2-5% in the visible/near-infrared to more than 25% in the mid-infrared can be expected.     

The electrochemical recovery of metallic palladium from spent electroless plating solution

Semiconductor bond pads are sometimes coated with palladium for good electrical properties and wire adhesion. The palladium is deposited by immersing the wafers in an electroless plating solution. When the plating solution is depleted and no longer achieves the desired results it is treated as waste. This work investigates the recovery of the remaining palladium in the waste solution by means of electrochemical deposition onto a high surface area cathode. Experiments show that the remaining palladium can be recovered economically and efficiently. This makes the process environmentally friendly and cost effective.