Applications of HCMM satellite data to the study of urban heating patterns

There are no author-identified significant results in this report

A method for estimating soil moisture availability

A method for estimating values of soil moisture based on measurements of infrared surface temperature is discussed. A central element in the method is a boundary layer model. Although it has been shown that soil moistures determined by this method using satellite measurements do correspond in a coarse fashion to the antecedent precipitation, the accuracy and exact physical interpretation (with respect to ground water amounts) are not well known. This area of ignorance, which currently impedes the practical application of the method to problems in hydrology, meteorology and agriculture, is largely due to the absence of corresponding surface measurements. Preliminary field measurements made over France have led to the development of a promising vegetation formulation (Taconet et al., 1985), which has been incorporated in the model. It is necessary, however, to test the vegetation component, and the entire method, over a wide variety of surface conditions and crop canopies

Preliminary assessment of soil moisture over vegetation

Modeling of surface energy fluxes was combined with in-situ measurement of surface parameters, specifically the surface sensible heat flux and the substrate soil moisture. A vegetation component was incorporated in the atmospheric/substrate model and subsequently showed that fluxes over vegetation can be very much different than those over bare soil for a given surface-air temperature difference. The temperature signatures measured by a satellite or airborne radiometer should be interpreted in conjunction with surface measurements of modeled parameters. Paradoxically, analyses of the large-scale distribution of soil moisture availability shows that there is a very high correlation between antecedent precipitation and inferred surface moisture availability, even when no specific vegetation parameterization is used in the boundary layer model. Preparatory work was begun in streamlining the present boundary layer model, developing better algorithms for relating surface temperatures to substrate moisture, preparing for participation in the French HAPEX experiment, and analyzing aircraft microwave and radiometric surface temperature data for the 1983 French Beauce experiments

Collaborative Control for a Robotic Wheelchair: Evaluation of Performance, Attention, and Workload

Powered wheelchair users often struggle to drive safely and effectively and in more critical cases can only get around when accompanied by an assistant. To address these issues, we propose a collaborative control mechanism that assists the user as and when they require help. The system uses a multiple–hypotheses method to predict the driver’s intentions and if necessary, adjusts the control signals to achieve the desired goal safely. The main emphasis of this paper is on a comprehensive evaluation, where we not only look at the system performance, but, perhaps more importantly, we characterise the user performance, in an experiment that combines eye–tracking with a secondary task. Without assistance, participants experienced multiple collisions whilst driving around the predefined route. Conversely, when they were assisted by the collaborative controller, not only did they drive more safely, but they were able to pay less attention to their driving, resulting in a reduced cognitive workload. We discuss the importance of these results and their implications for other applications of shared control, such as brain–machine interfaces, where it could be used to compensate for both the low frequency and the low resolution of the user input

Applications of HCMM satellite data to the study of urban heating patterns

There are no author-identified significant results in this report

Interactive initialization of heat flux parameters for numerical models using satellite temperature measurements

Progress made in HCMM research, including testing the interactive minicomputer system and preparation of a paper on the analysis of regional scale soil moisture patterns, is summarized. An exhibit on remote sensing including a videotape display of HCMM images, most of them of the State College area, was prepared

Orbitally Excited Baryons in Large N_c QCD

We present a model-independent analysis of the mass spectrum of nonstrange l=1 baryons in large N_c QCD. The 1/N_c expansion is used to select and order a basis of effective operators that spans the nine observables (seven masses and two mixing angles). Comparison to the data provides support for the validity of the 1/N_c expansion, but also reveals that only a few nontrivial operators are strongly preferred. We show that our results have a consistent interpretation in a constituent quark model with pseudoscalar meson exchange interactions.Comment: 4 pages LaTeX. Invited parallel session talk presented at the XVth Particles and Nuclei International Conference (PANIC99), June 10, 1999, Uppsala, Swede

Beliefs about Exchange-Rate Stability: Survey Evidence From the Currency Board in Bulgaria

We use unique survey data from Bulgaria’s currency board to examine the reasons for persistent incomplete credibility of a financial stabilization regime. Although it produced remarkably positive effects in terms of sustained low inflation since 1997, the currency board has not achieved full credibility. This is not uncommon in other less-developed countries with fixed exchange rate regimes. Our results reveal that incomplete credibility is explained primarily by concerns about external economic shocks and the persistent high unemployment in the country. Past experiences with high inflation do not rank among the top reasons to expect financial instability in the future.http://deepblue.lib.umich.edu/bitstream/2027.42/40091/3/wp705.pd

Fixed Exchange Rate Credibility with Heterogeneous Expectations

After disinflation has been achieved, agents who form more sophisticated forecasts have lower confidence in the sustainability of a peg compared to less sophisticated agents. Furthermore, sustained financial stability leads to a declining proportion of sophisticated agents. Thus, the credibility of a fixed exchange rate regime grows over time partly because fewer people pay attention to the workings of the monetary regime. These results are derived in a rules-versus-discretion model of a fixed exchange rate regime with heterogeneous agents. We provide unique supporting evidence using data on expectations and information about the monetary regime from Bulgaria's currency board. Working Paper 06-2