62,154 research outputs found
A multidisciplinary study of earth resources imagery of Australia, Antarctica and Papua, New Guinea
The author has identified the following significant results. A thirteen category recognition map was prepared, showing forest, water, grassland, and exposed rock types. Preliminary assessment of classification accuracies showed that water, forest, meadow, and Niobrara shale were the most accurately mapped classes. Unsatisfactory results, were obtained in an attempt to discrimate sparse forest cover over different substrates. As base elevation varied from 7,000 to 13,000 ft, with an atmospheric visibility of 48 km, no changes in water and forest recognition were observed. Granodiorite recognition accuracy decreased monotonically as base elevation increased, even though the training set location was at 10,000 ft elevation. For snow varying in base elevation from 9400 to 8420 ft, recognition decreases from 99% at the 9400 ft training set elevation to 88% at 8420 ft. Calculations of expected radiance at the ERTS sensor from snow reflectance measured at the site and from Turner model calculations of irradiance, transmission and path radiance, reveal that snow signals should not be clipped, assuming that calculations and ERTS calibration constants were correct
Improving performance through concept formation and conceptual clustering
Research from June 1989 through October 1992 focussed on concept formation, clustering, and supervised learning for purposes of improving the efficiency of problem-solving, planning, and diagnosis. These projects resulted in two dissertations on clustering, explanation-based learning, and means-ends planning, and publications in conferences and workshops, several book chapters, and journals; a complete Bibliography of NASA Ames supported publications is included. The following topics are studied: clustering of explanations and problem-solving experiences; clustering and means-end planning; and diagnosis of space shuttle and space station operating modes
DURABLE CONSUMPTION AS A STATUS GOOD: A STUDY OF NEOCLASSICAL CASES
In this paper we extend the representative agent model of the consumer to incorporate durable consumption goods that generate status, where status depends on relative consumption. The study is done in the neoclassical context and incorporates analytical and numerical results. In the closed economy framework both endogenous and fixed employment cases are considered. A small open economy version of the model is also developed. We derive the intertemporal equilibria and establish that in all instances they are saddlepoint stable. Among our principle results, we show in the closed economy context with endogenous work effort that an increase in the degree of status preference raises durable consumption, its stock, employment, and physical capital. In addition, an increase in the status preference parameter affects the stable speeds of adjustment in the special case of fixed employment, depending on whether it raises or lowers the intertemporal elasticity of substitution. These results extend, in general, to the small open economStatus Seeking, Durable Consumption, Relative Consumption
Investment and Current Account Dynamics in an Open Economy Status Seeking Framework
In this paper we analyze the implications of status-preference, modelled as relative wealth, for the current account in a small open economy framework with capital stock dynamics. We demonstrate that the transitional dynamics of the economy is characterized by two distinct speeds of adjustment: a speed of adjustment arising from status-preference and a speed of adjustment arising from installation costs of investment. This structure implies that the current account balance depends on both speeds of adjustment as well as on the long-run equilibrium, which is a function of the degree of status-consciousness. As a consequence, the current account can exhibit non-monotonic behavior in transition to the steady-state equilibrium.Current account, Status seeking, Relative wealth, Open economy dynamics
Design considerations for on-orbit servicing
An overview of the general design of space vehicles serviced in orbit is presented. The basic space vehicle systems, subsystems, modules components, and associated appendages comprise the elements to be considered. Primary emphasis is given to the multi-disciplinary considerations in the development of requirements, and in particular, design of the space vehicle to facilitate orbital sevice by the extra-vehicular crew person(s)
A study of the usefulness of Skylab EREP data for earth resources studies in Australia
There are no author-identified significant result in this report
Current Account Dynamics in a Small Open Economy Model of Status Seeking
In this paper we will use a status-preference framework, together with a standard cost of adjustment investment function, to study the dynamics of the small open economy current account balance. We demonstrate that the transitional dynamics of the economy is characterized by two speeds of adjustment: a speed of adjustment arising from status-preference and a speed of adjustment arising from installation costs of investment. This structure implies that the current account balance depends on both speeds of adjustment as well as on the long-run equilibrium. As a consequence, the current account can exhibit non-monotonic behavior in transition to the steady state.Current account, Status seeking, Relative wealth, Open economy dynamics
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