30,124 research outputs found
MAXIMUM LIKELIHOOD ESTIMATION OF A RANDOM COEFFICIENT MEAT DEMAND SYSTEM
The paper demonstrates that random coefficient models can be estimated by maximum likelihood if they are specified as generalized least squares models. The paper uses maximum likelihood estimation on a random-coefficient, meat-demand system. Statistical tests show that price elasticities are random, but expenditure elasticities are not. The statistical tests allow one to count the number of factors that cause randomness without requiring one to know what they are. There appear to be only two factors that make the price elasticities random.Demand and Price Analysis,
Preliminary power train design for a state-of-the-art electric vehicle
Power train designs which can be implemented within the current state-of-the-art were identified by means of a review of existing electric vehicles and suitable off-the-shelf components. The affect of various motor/transmission combinations on vehicle range over the SAE J227a schedule D cycle was evaluated. The selected, state-of-the-art power train employs a dc series wound motor, SCR controller, variable speed transmission, regenerative braking, drum brakes and radial ply tires. Vehicle range over the SAE cycle can be extended by approximately 20% by the further development of separately excited, shunt wound DC motors and electrical controllers. Approaches which could improve overall power train efficiency, such as AC motor systems, are identified. However, future emphasis should remain on batteries, tires and lightweight structures if substantial range improvements are to be achieved
Chebychev Trajectory Optimization Program /CHEBYTOP/ Final report
Digital computer program for interplanetary trajectory optimization and variable thrust dat
Exploring the potential X-ray counterpart of the puzzling TeV gamma-ray source HESS J1507-622 with new Suzaku observations
The unidentified VHE (E>100 GeV) gamma-ray source HESS J1507-622 seems to not
fit into standard models for sources related to young supernova remnants,
pulsar wind nebulae, or young stellar populations in general. This is due to
its intrinsically extended, but yet compact morphology, coupled with a relative
large offset (~3.5 deg) from the Galactic plane. Therefore, it has been
suggested that this object may be the first representative of a new distinct
class of extended off-plane gamma-ray sources. The distance to HESS J1507-622
is the key parameter to constrain the source's most important properties, such
as age and energetics of the relativistic particle population.
In this article we report on results of follow-up observations of the
potential X-ray counterpart with Suzaku. We present detailed measurements of
its spectral parameters and find a high absorbing hydrogen column density,
compatible with the total amount of Galactic gas in this direction. In
comparisons to measurements and models of the Galactic three-dimensional gas
distribution we show that the potential X-ray counterpart of HESS J1507-622 may
be located at the far end of the Galaxy. If the gamma-ray source is indeed
physically connected to this extended X-ray source, this in turn would place
the object outside of the usual distribution of Galactic VHE gamma-ray
emitters.Comment: 12 pages, 7 figures, accepted for publication by MNRA
Applying and Extending the Sustainable Value Method related to Agriculture â an Overview
Sustainable Value is a method to measure the contribution of an economic entity, such as a farm or the entire agricultural sector, towards the sustainability (sustainable development) of a region, a country or on a global scale. A positive sustainable value is created once resources are used more efficiently than by a benchmark. It shows the excess return that is created or lost by the use of economic, environmental and social resources by an economic entity relative to a benchmark. The purpose of this paper is to give an overview on the characteristics and requirements of the SV and to provide information on (a) possible applications and (b) extensions of the SV method related to the agricultural sector. A particular emphasis is put on the choice of sustainability indicators (resource figures, welfare figure) to be included, the generic steps of SV calculation, the meaning of weighting and aggregation in the SV, the role of the Return-to-Cost Ratio in taking farm size into consideration, and the interpretation and communication of the results of an agriculture-related SV assessment. After sketching out possible extensions and variations of the SV method, the paper closes with a summary of those aspects to keep in mind when applying the SV to agriculture.sustainability contributions, value, measurement, Environmental Economics and Policy,
A comparative study of nonparametric methods for pattern recognition
The applied research discussed in this report determines and compares the correct classification percentage of the nonparametric sign test, Wilcoxon's signed rank test, and K-class classifier with the performance of the Bayes classifier. The performance is determined for data which have Gaussian, Laplacian and Rayleigh probability density functions. The correct classification percentage is shown graphically for differences in modes and/or means of the probability density functions for four, eight and sixteen samples. The K-class classifier performed very well with respect to the other classifiers used. Since the K-class classifier is a nonparametric technique, it usually performed better than the Bayes classifier which assumes the data to be Gaussian even though it may not be. The K-class classifier has the advantage over the Bayes in that it works well with non-Gaussian data without having to determine the probability density function of the data. It should be noted that the data in this experiment was always unimodal
Chebychev trajectory optimization program /CHEBYTOP 2/ Final report
Computer program for electric propelled spacecraft interplanetary, flyby, and rendezvous trajectory optimization based on Chebyshev approximation and polynomial representation
A Comparative Study of Nonparametric Methods for Pattern Recognition
The main objective of this thesis is to determine and compare the classification error probabilities of several nonparametric methods to parametric ones in practical or near practical conditions using computer simulation. The usefulness of the Asymptotic Relative Efficiency (ARE) is also observed. The ARE is used to compare one algorithm with another in the limit case conditions which are far from practical circumstances. Details of the ARE concept is given in Chapter II and some of the literatures. The next objective is the investigation of the complexity of the several algorithms studied. Many investigators are implementing their algorithms on computers, and since the computer time is determined by the complexity of the algorithm, a very crucial aspect of any algorithm is its complexity. If the data are processed by other than computer, the hardware of the system required will become more expensive and complicated as the calculation gets more complex. In this respect, the calculation problem is studied. The previously stated objectives are performed extensively with two-class problems, but the actual classification problem in imagery recognition usually is a multi-class one. Hence, the generalization of the two-class problem to the multi-class one is studied as a minor objective. One of the important aspects of this work is that the performance of each algorithm with various data distribution conditions can be found in very practical, not theoretical, circumstances. The adoption of a method as a data processing algorithm by a designer of the system can be based more positively on the results of this work. The merits and the limitations of the nonparametric methods are also determined by the actual handling of data through each method. The effects of sample sizes and signal-to-noise ratios on error probabilities are experimented to give more insight into the algorithm and to see various situational behavior of the method. Through the experiments, determining a nonparametric threshold happens to be an important matter in actual applications of algorithms. This is also studied, and a specific result is drawn
The Impact of Domestic and Import Prices on U.S. Lamb Imports: A Production System Approach
As U.S. lamb imports increased relative to domestic production, and the relative share of chilled to frozen lamb imports increased, importers of chilled lamb have become less responsive to domestic and import prices, while the direct opposite is the case for frozen lamb imports. From 1990 to 2003, chilled lamb imports from Australia and New Zealand became less and less responsive to U.S. prices, and frozen imports became more responsive. Unconditional own-price elasticities also show that, over time, imports of chilled lamb became less responsive to import prices while frozen imports became more responsive to import prices.lamb, demand, imports, trade, import demand, production, International Relations/Trade,
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