12,658 research outputs found
Index to 1984 NASA Tech Briefs, volume 9, numbers 1-4
Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1984 Tech B Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences
Hysteresis-based design of dynamic reference trajectories to avoid saturation in controlled wind turbines
The main objective of this paper is to design a dynamic reference trajectory based on hysteresis to avoid saturation in controlled wind turbines. Basically, the torque controller and pitch controller set-points are hysteretically manipulated to avoid saturation and drive the system with smooth dynamic changes. Simulation results obtained from a 5MW wind turbine benchmark model show that our proposed strategy has a clear added value with respect to the baseline controller (a well-known and accepted industrial wind turbine controller). Moreover, the proposed strategy has been tested in healthy conditions but also in the presence of a realistic fault where the baseline controller caused saturation to nally conduct to instability.Peer ReviewedPostprint (author's final draft
Aerospace Medicine and Biology. A continuing bibliography with indexes
This bibliography lists 244 reports, articles, and other documents introduced into the NASA scientific and technical information system in February 1981. Aerospace medicine and aerobiology topics are included. Listings for physiological factors, astronaut performance, control theory, artificial intelligence, and cybernetics are included
Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 192
This bibliography lists 247 reports, articles, and other documents introduced into the NASA scientific and technical information system in March 1979
Automotive automation: Investigating the impact on drivers' mental workload
Recent advances in technology have meant that an increasing number of vehicle driving
tasks are becoming automated. Such automation poses new problems for the ergonomist.
Of particular concern in this paper are the twofold effects of automation on mental
workload - novel technologies could increase attentional demand and workload,
alternatively one could argue that fewer driving tasks will lead to the problem of reduced
attentional demand and driver underload. A brief review of previous research is
presented, followed by an overview of current research taking place in the Southampton
Driving Simulator. Early results suggest that automation does reduce workload, and that
underload is indeed a problem, with a significant proportion of drivers unable to
effectively reclaim control of the vehicle in an automation failure scenario. Ultimately,
this research and a subsequent program of studies will be interpreted within the
framework of a recently proposed theory of action, with a view to maximizing both
theoretical and applied benefits of this domain
Artificial neural networks and physical modeling for determination of baseline consumption of CHP plants
An effective modeling technique is proposed for determining baseline energy consumption in the industry.
A CHP plant is considered in the study that was subjected to a retrofit, which consisted of the implementation
of some energy-saving measures. This study aims to recreate the post-retrofit energy consumption
and production of the system in case it would be operating in its past configuration (before retrofit) i.e., the
current consumption and production in the event that no energy-saving measures had been implemented.
Two different modeling methodologies are applied to the CHP plant: thermodynamic modeling and artificial
neural networks (ANN). Satisfactory results are obtained with both modeling techniques. Acceptable
accuracy levels of prediction are detected, confirming good capability of the models for predicting plant
behavior and their suitability for baseline energy consumption determining purposes. High level of robustness
is observed for ANN against uncertainty affecting measured values of variables used as input in the
models. The study demonstrates ANN great potential for assessing baseline consumption in energyintensive
industry. Application of ANN technique would also help to overcome the limited availability of
on-shelf thermodynamic software for modeling all specific typologies of existing industrial processes
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An Assessment of PIER Electric Grid Research 2003-2014 White Paper
This white paper describes the circumstances in California around the turn of the 21st century that led the California Energy Commission (CEC) to direct additional Public Interest Energy Research funds to address critical electric grid issues, especially those arising from integrating high penetrations of variable renewable generation with the electric grid. It contains an assessment of the beneficial science and technology advances of the resultant portfolio of electric grid research projects administered under the direction of the CEC by a competitively selected contractor, the University of California’s California Institute for Energy and the Environment, from 2003-2014
Aeronautical engineering: A continuing bibliography, supplement 122
This bibliography lists 303 reports, articles, and other documents introduced into the NASA scientific and technical information system in April 1980
Implementation of Neuroidentifiers Trained by PSO on a PLC Platform for a Multimachine Power System
Power systems are nonlinear with fast changing dynamics. In order to design a nonlinear adaptive controller for damping power system oscillations, it becomes necessary to identify the dynamics of the system. This paper demonstrates the implementation of a neural network based system identifier, referred to as a neuroidentifier, on a programmable logic controller (PLC) platform. Two separate neuroidentifiers are trained using the particle swarm optimization (PSO) algorithm to identify the dynamics in a two-area four machine power system, one neuroidentifier for Area 1 and the other for Area 2. The power system is simulated in real time on the Real Time Digital Simulator (RTDS). The PLC implementing two neural networks and the PSO training algorithm is interfaced in a real time to the RTDS. Typical results are presented showing that PLC platform is able to implement the neuroidentifiers to sufficiently identify the dynamics of the two-area four machine power system
Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 187
This supplement to Aerospace Medicine and Biology lists 247 reports, articles and other documents announced during November 1978 in Scientific and Technical Aerospace Reports (STAR) or in International Aerospace Abstracts (IAA). In its subject coverage, Aerospace Medicine and Biology concentrates on the biological, physiological, psychological, and environmental effects to which man is subjected during and following simulated or actual flight in the earth's atmosphere or in interplanetary space. References describing similar effects of biological organisms of lower order are also included. Emphasis is placed on applied research, but reference to fundamental studies and theoretical principles related to experimental development also qualify for inclusion. Each entry in the bibliography consists of a bibliographic citation accompanied in most cases by an abstract
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