4,956 research outputs found
Auctions and trading in energy markets -- an economic analysis
Auctions are playing an increasingly prominent role in the planning and operation of energy markets. Comparing the New Electricity Trading Arrangements to the former electricity Pool in England and Wales requires some analysis of the relative merits of uniform versus discriminatory pricing rules, and use of the gas network in Britain and electricity interconnectors around Europe is allocated on the basis of auction results. In this paper we discuss the changes in the trading arrangements in the electricity industry in England and Wales as well as some of the results to date. We also look at the wider issue of using auctions to replace regulation by market solutions for managing the natural monopolies in energy markets.auctions, electricity, gas, interconnectors, networks
An AI approach for scheduling space-station payloads at Kennedy Space Center
The Payload Processing for Space-Station Operations (PHITS) is a prototype modeling tool capable of addressing many Space Station related concerns. The system's object oriented design approach coupled with a powerful user interface provide the user with capabilities to easily define and model many applications. PHITS differs from many artificial intelligence based systems in that it couples scheduling and goal-directed simulation to ensure that on-orbit requirement dates are satisfied
Causal and stable reduced-order model for linear high-frequency systems
With the ever-growing complexity of high-frequency systems in the electronic industry, formation of reduced-order models of these systems is paramount. In this reported work, two different techniques are combined to generate a stable and causal representation of the system. In particular, balanced truncation is combined with a Fourier series expansion approach. The efficacy of the proposed combined method is shown with an example
An Infestation of the Bat Bug Cimex pilosellus on an Arkansas Population of Big Brown Bats (Eptesicus fuscus)
Dental Pathology in Selected Carnivores from Arkansas
The occurrence and kinds of dental pathology in wild carnivore populations in Arkansas were investigated through examination of 1295 skulls of bobcat (Felis rufus), river otter (Lutra canadensis), gray fox (Urocyon cinereoargenteus), coyote (Canis latrans), and raccoon (Procyon lotor). Pulpitis or abscesses in broken or otherwise exposed teeth were noted in all species, but bobcats had the fewest exposures while otter and gray foxhad the most. Osteomyelitis occurred in all species except the bobcat. Caries were noted in the coyote, raccoon, and gray fox. Otter and coyote had alveolar thinning, and coyote had enamel dysplasia and maxillary sinusitis
Barriers and Bridges: An Action Plan for Overcoming Obstacles and Unlocking Opportunities for African American Men in Pittsburgh
Among the region's residents, Pittsburgh's African American men have historically and disproportionately faced unprecedented barriers to economic opportunities. This study, supported by The Heinz Endowments, focuses on structural barriers that contribute to persistent racial disparities in the Pittsburgh region. Structural barriers are obstacles that collectively affect a group disproportionately and perpetuate or maintain stark disparities in outcomes. Structural barriers can be policies, practices, and other norms that favor an advantaged group while systematically disadvantaging a marginalized group. A community touched by racebased structural barriers can be identified by the racial and economic stratification of its residents; Pittsburgh, like many large cities in the United States, fits that description
Application of magnitude estimation scaling to the assessment of subjective loudness response to simulated sonic booms
A laboratory study was conducted for the following reasons: (1) to investigate the application of magnitude estimation scaling for evaluating the subjective loudness of sonic booms; and (2) to compare the relative merits of magnitude estimation and numerical category scaling for sonic boom loudness evaluation. The study was conducted in the NASA LeRC's sonic boom simulator and used a total of 80 test subjects (48 for magnitude estimation and 32 for numerical category scaling). Results demonstrated that magnitude estimation was a practical and effective method for quantifying subjective loudness of sonic booms. When using magnitude estimation, the subjects made valid and consistent ratio judgments of sonic boom loudness irrespective of the frequency of presentation of the standard stimulus. Presentation of the standard as every fourth stimulus was preferred by the subjects and is recommended as the standard presentation frequency to be used in future tests
Moanalua Valley - An Interdisciplinary Approach
paper proposing to implement an interdisciplinary program at the secondary level of
education in Moanalua valle
In-flight acoustic measurements on a light twin-engined turboprop airplane
Four series of flight tests were conducted to measure sound pressure levels inside and outside the cabin of a twin-engined turboprop airplane. Particular emphasis was placed on harmonics of the propeller blade passage frequency. The cabin was unfurnished for the first three flights, when the main objective was to investigate the repeatability of the data. For the fourth flight, the cabin was treated with fiberglass batts. Typically, the exterior sound pressure levels were found to vary 3 to 5 dB for a given harmonic, but variations as high as 8 dB were observed. The variability of harmonic levels within the cabin was slightly higher but depended on control of the relative phase between the propellers; when phase was not controlled the average variability was about 10 dB. Noise reductions provided by the fuselage structure were in the range of 20 to 40 dB, when an exterior microphone in the plane of rotation of the propeller was used as reference
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