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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records

The Essence of Reactivity

Reactive programming, functional reactive programming, event-based programming, stream programming, and temporal logic all share an underlying commonality: values can vary over time. These languages differ in multiple ways, including the nature of time itself (e.g., continuous or discrete, dense or sparse, implicit or explicit), on how much of the past and future can be referenced, on the kinds of values that can be represented, as well as the mechanisms used to evaluate expressions or formulas. This paper presents a series of abstractions that capture the essence of different forms of time variance. By separating the aspects that differentiate each family of formalisms, we can better express the commonalities and differences between them. We demonstrate our work with a prototype in Haskell that allows us to write programs in terms of a generic interface that can be later instantiated to different abstractions depending on the desired target.

reactive programming↗

Emergence of Relations and the Essence of Learning: A Review of Sidman's Equivalence Relations and Behavior: A Research Story

Sidman addresses two very important questions in Equivalence Relations and Behavior: A Research Story: What are the bases of behavioral competence? And how do units of learning become related? The book recounts the story of how an understanding of emergent relations and competencies was achieved through studies in his teaching-research program with mentally retarded subjects. Although children normally accrue vast networks of relations between stimuli and events, those with mental retardation typically do not. Consequently, by learning how to establish those networks, Sidman and his students contribute richly both to the cultivation of competencies by their subjects and, more generally, to an understanding of real-world human behavior. The basic equivalence paradigm affords the subject feedback and reinforcement for very specific choices during training, but the test is not for those choices! Rather, tests for equivalence look for new choices, ones seemingly quite foreign to the training regimen. The tests for equivalence relations entail presentations of stimuli that were the options for conditional choice during reinforced training. In tests of equivalence, correct choices are novel; hence, they have never been reinforced during training. The study of equivalence relations can encourage the emergence of new perspectives that are more symbiotic than competitive. In full acknowledgment of the important role and contributions made by those who identify themselves as experimental analysts of behavior, it is timely that rapprochements be worked toward, as indeed they are, to meld that perspective with others of our time. Both our research methods and our expectations about the nature of the learning process and the abilities of our subjects can delimit what they might learn and what we, in turn, learn about their learning. The text will be of great value for instruction at the upper-division and graduate levels. Its impact will be substantial, for it defines an important advance in our efforts to understand the richness of behavior in both humans and nonhuman animals. Although not presented to that end, the book might also serve to bridge communications with other groups of animal researchers whose interests lie more in a comparative or ethological framework.

Rumbaugh, Duane M.↗

Emergence of relations and the essence of learning: a review of Sidman's Equivalence relations and behavior: a research story. Book review

The author reviews and comments on the book Equivalence relations and behavior: a research story by Murray Sidman. Sidman's book reports his research about equivalence relations and competencies in children with mental retardation and how it relates to behavior. Sidman used the idea of stimulus-stimulus relations among features of the environment to develop his theories about equivalence relations. Experimental work with children and animals demonstrated their ability to use equivalence relations to learn new tasks. The subject received feedback and reinforcement for specific choices made during training, then was presented with new choices during testing. Results of the tests indicate that subjects were able to establish relations and retrieve them in different situations.

NASA Discipline Space Human Factors↗

Essence of Water

Explore the source record for details and available documents.

Sushel Unninayar↗

THE ECONOMIC EFFECTS OF THE SPACE PROGRAM

The purpose of this paper is to discuss the economic impact of the amazing space program presented in the preceding papers. My function is to view the space program objectively as an economist so as to assess its impact upon the Nation's economy as a whole and upon certain regions in particular. In order to be objective, I will not take the extreme view that our entire lives will be changed by this program overnight-we will not all be wearing air-conditioned Moonsuits in 2 years and commuting to work by individual miniaturized Rocketpacks. An attempt will be made to avoid the other extreme of thinking that the space program is the greatest boondoggle since the Pyramids; it is not merely a form of scientific leaf-raking on a gigantic scale. My definition of the space program includes the program of the National Aeronautics and Space Administration (NASA) and some work of other agencies doing related space exploration, particularly the Department of Defense. In essence, I hope to answer the question: What will NASA's program mean to the participants in the Nation's economy?

ECONOMICS↗

Handbook for the study of electric propulsion systems

A compendium of techniques and basic information useful to the preliminary performance analysis of power-limited (low-acceleration, electric) propulsion systems applied to space missions is presented. The material is in handbook form and is reasonably complete within itself insofar as a basic understanding of the techniques and procedures is required for one to acquire facility in computing performance. This, in essence, is the objective of the handbook. The accumulation and organization of the material selected for inclusion was guided by the desire for simplicity and computational ease while maintaining a sufficient level of completeness for a general understanding.

Ragsac, R. V.↗

ERTS direct readout ground station study

A system configuration which provides for a wide variety of user requirements is described. Two distinct user types are considered and optimized configurations are provided. Independent satellite transmission systems allow simultaneous signal transmission to Regional Collection Centers via a high data rate channel and to local users who require near real time consumption of lower rate data. In order to maximize the ultimate utility of this study effort, a parametric system description is given such that in essence a shopping list is provided. To achieve these results, it was necessary to consider all technical disciplines associated with high resolution satellite imaging systems including signal processing, modulation and coding, recording, and display techniques. A total systems study was performed.

Source record↗

Methods and approaches to dosimetry

The development of a dosimetric system capable of determining energy depositions in tissue regions that are smaller than a few 100 nanometers is projected. These objectives are met by evaluation of the data produced by a macro-subsystem and a micro-subsystem. Both systems are in essence multiple ionization chambers that are normally operated in a gated pulse mode. The macro-system yields absorbed radiation dose as a function of location in a phantom of the human trunk when it operates in the dose mode; it registers only those sections as a signal in which the primary particle or any of its secondaries have passed, in the pulse mode. The function of the micro-system is to provide detailed information of the track structure by determining lateral energy spread due to delta ray formation or other secondary particle production.

Rossi, H. H.↗

Convective heating measurement by means of an infrared camera

The development of rapid and accurate wind tunnel techniques to measure convective heating distributions in complex reentry configurations is discussed. Major emphasis was put on the infrared camera technique. Its essence is the measurement of infrared emission from the surface of a wind tunnel model as a function of time. Prior calibration of the infrared camera relates the emission to the surface temperature of the model. The time history of the surface temperature can then be related to the heating rate by standard techniques. The output of the camera is an electrical signal that is tape-recorded in analog form, then digitized and processed by computer, so that automated and relatively rapid data reduction can be accomplished. In addition, the camera produces real-time visual displays of the infrared emission as pictures on an oscilloscope screen. These pictures give immediate indications of hot and cool spots on the model.

Compton, D. L.↗

Origin of strong magnetic fields.

A possible mechanism by which extremely strong magnetic fields in neutron stars and white dwarfs could originate involves the existence of thermodynamic equilibrium states (LOFER states) of an electron gas. The essence of the stability theory of a LOFER state is discussed. The extended electronic system considered is in contact with a thermal bath in the presence of an external magnetic field. It is found that it is not necessary to require absolute stability in order to realize a LOFER state in nature.

Canuto, V.↗

SYMAT, COVAR: Test Procedures for Matrix Calculations

The FORTRAN subroutine SYMAT and related subroutines are described. In essence SYMAT is an iterative algorithm in which the problem of finding eigenvalues and eigenvectors of a real symmetric matrix is transformed into an equivalent problem of finding eigenvalues and eigenvectors of an infinite sequence of matrices of order two. A DEMO PROGRAM contains a subroutine COVAR which is used to compute the covariance matrix (denoted by A) of a data matrix (denoted by X). Since a covariance matrix is symmetric it can be analyzed by using subroutine SYMAT.

Morris, W. L.↗

Analysis of operator participation

The problem of providing a psychological conception of the analysis of operator participation in a form that will allow the qualitative approach to be combined with the quantitative approach is examined. This conception is based on an understanding of the essence of human endeavor in automated control systems that now determine the development of society's productive forces and that are the main object of ergonomic research. Two main types of operator participation were examined; information retrieval with immediate service and information retrieval with delayed service.

Zarakovskiy, G. M.↗

Mini-arc orbit determination for the Geos C altimetry experiment.

The problem is, given simultaneous observations of an altimeter-bearing geodetic satellite, from three or more high-precision radar stations, to determine its orbit to submeter accuracy in the presence of perturbations arising from strong, localized gravitational anomalies. A new solution to this problem involves the use of an f and g series specialized to the determination of radial distance (pertinent to the satellite altimeter experiment) to process data over a very short arc (e.g., 6 sec to 10 min). Such a short arc is termed a 'mini-arc.' In this approach, the data batches are connected by dynamics, rather than by the usual curve fit to a power series in time. A nonunity value of the mass factor is introduced to serve as an 'alias' for the perturbations that affect the satellite's path during the mini arc. The essence of the mini-arc approach is to include the influence of the far, or relatively lower-order, force field analytically and to solve for the remaining fine structure with accuracies that can approach a few centimeters.

Baker, R. M. L., Jr.↗

Mathematical modeling of spinning elastic bodies for modal analysis.

The problem of modal analysis of an elastic appendage on a rotating base is examined to establish the relative advantages of various mathematical models of elastic structures and to extract general inferences concerning the magnitude and character of the influence of spin on the natural frequencies and mode shapes of rotating structures. In realization of the first objective, it is concluded that except for a small class of very special cases the elastic continuum model is devoid of useful results, while for constant nominal spin rate the distributed-mass finite-element model is quite generally tractable, since in the latter case the governing equations are always linear, constant-coefficient, ordinary differential equations. Although with both of these alternatives the details of the formulation generally obscure the essence of the problem and permit very little engineering insight to be gained without extensive computation, this difficulty is not encountered when dealing with simple concentrated mass models.

Likins, P. W.↗

Origin of QSO absorption lines

Consideration of the origin of the absorption lines in QSOs with observed absolute redshifts much less than the empirical values. As a possible alternative to the plasmoid mechanism for decreasing the relatively large possible macroscopic or bulk motions in QSO clouds, it is shown that certain large relative bulk motions in QSO clouds can be dissipated without the presence of strong magnetic fields and without large adiabatic expansions. The essence of the argument is that a cloud with convergent internal velocities can coalesce inelastically, because the internal kinetic energy can be dissipated and radiated away. There are thus indications that observed QSO absorption clouds may have their origin in clouds with internal velocities which are convergent.

Opher, R.↗

Determining spacecraft and airplane angular orientation from star photographs

The advantages of determining spacecraft angular orientation from star photographs include the documental nature and objectivity of the photographic image and also the high accuracy of construction of the reference system based on the stars. Use of the method presupposes installation aboard the vehicle of a specialized photographic camera adapted for photographing the stellar sky. From the mathematical viewpoint, the essence of the method amounts to: (1) Certain directions in space are identified and their direction cosines are determined in a specified coordinate system. (2) The direction cosines of these same directions are determined relative to a coordinate system fixed with the vehicle. (3) The sought angular orientation of the vehicle is calculated using the coupling equations between the specified and vehicle-fixed coordinate systems. In principle, vehicle angular orientation can be determined relative to any given reference system.

Elbakyan, K. I.↗