Showing papers in "IEEE Transactions on Military Electronics in 1964"
TL;DR: In this article, it was shown that the state vector of a linear system can be reconstructed from observations of the system inputs and outputs, and that the observer which reconstructs this state vector is itself a linear systems whose complexity decreases as the number of output quantities available increases.
Abstract: In much of modern control theory designs are based on the assumption that the state vector of the system to be controlled is available for measurement. In many practical situations only a few output quantities are available. Application of theories which assume that the state vector is known is severely limited in these cases. In this paper it is shown that the state vector of a linear system can be reconstructed from observations of the system inputs and outputs. It is shown that the observer, which reconstructs the state vector, is itself a linear system whose complexity decreases as the number of output quantities available increases. The observer may be incorporated in the control of a system which does not have its state vector available for measurement. The observer supplies the state vector, but at the expense of adding poles to the over-all system.
1,581 citations
TL;DR: A method of inverse probability is obtained which permits maximum likelihood estimates to be made of the true data-surveillance object association and the maximum likelihood estimator is given in a form that lends itself to sequential computations performed in real time as the data arrives.
Abstract: This paper contains a theoretical analysis of the data association problem of a common type of surveillance system. By a method of inverse probability, the optimal data processor is obtained which permits maximum likelihood estimates to be made of the true data-surveillance object association. The maximum likelihood estimator is given in a form that lends itself to sequential computations performed in real time as the data arrives. Examples of the use of this estimator make clear the precise mathematical meaning of such terms as tentative, confirmed, and established data tracks, and the concept of search areas. The analytical technique is of general use in a variety of surveillance situations. Computer implementations are possible.
243 citations
TL;DR: A general survey of the principles of radio astronomy receivers is presented and a total-power receiver is analyzed as a basic radio telescope receiver to obtain the performance of other receiver types such as the Dicke receiver, Graham's receiver, correlation receiver, and phase-switching receiver.
Abstract: A general survey of the principles of radio astronomy receivers is presented. System noise temperature, the sensitivity of different receiver types, and the calibration of receivers are studied. A total-power receiver is analyzed as a basic radio telescope receiver and. the results are used to obtain the performance of other receiver types such as the Dicke receiver, Graham's receiver, correlation receiver, and phase-switching receiver.
186 citations
TL;DR: In this article, the authors extend the analytic procedures to semi-Markov processes, Markov processes whose transition times can also be arbitrary random variables, and derive expressions for the interval transition probabilities, the probabilities that the system will be in each state after the passage of a time interval of length t, and find the limit of these probabilities when t is large.
Abstract: Flow graph analysis has proved a valuable approach to the study of probabilistic systems. This paper extends the analytic procedures to semi-Markov processes, Markov processes whose transition times can also be arbitrary random variables. First we present the basic theory of the semi-Markov process. We derive expressions for the interval transition probabilities, the probabilities that the system will be in each state after the passage of a time interval of length t, and find the limit of these probabilities when t is large. Then we develop the flow graph interpretation of these relations. We consider the special cases of counting transitions, transient processes, and first passage times. We investigate the effect on interval transition probabilities of starting the process in different ways, including choosing a time at random to begin observation of the process. We find that results are often most conveniently expressed by the matrix flow graph for the process.
112 citations
Journal Article•
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TL;DR: A survey of radio telescope design can be found in this article, where the authors describe various types of radio telescopes which have been built and tested, and outline the astronomical needs which they fulfill.
Abstract: A radio telescope is used in radio astronomy to measure the intensity of the radiation received from various parts of the sky. Such a telescope must be able both to detect and to locate faint radio sources of small angular size, and also to measure the brightness distribution across extended radio sources or over large sky areas. Ideally the telescope should be capable of making such measurements over a wide frequency range and for different types of polarization of the incoming waves. The noise powers available in radio astronomy are very small, and some of the radio sources have angular sizes or angular structure of, perhaps, only one second of arc, so that a radio telescope needs both high gain and good resolving power. The paper describes various types of radio telescopes which have been built and tested, and outlines the astronomical needs which they fulfill. The parabolic reflector antenna is first described, with particular reference to the fully steerable 210-foot telescope at the Australian National Radio Astronomy Observatory and to the 300-foot transit telescope at the U. S. National Radio Astronomy Observatory. Of the telescopes which use fixed or partly fixed reflector surfaces, those at the University of Illinois, at the Nancay station of the Paris Observatory, and at the Arecibo Ionospheric Observatory in Puerto Rico are described in some detail. Instruments in which the resolution is improved without a corresponding increase of collecting area, such as the cross-type antennas, are briefly described. The future progress of radio telescope design is certain to follow the development of parabolic dishes to still greater sizes, and the exploitation of synthetic antenna systems; the article concludes with a survey of both developments.
65 citations
TL;DR: An experimental rangefinder designed and fabricated to show feasibility of the spinning reflector technique to optical ranging is described, and practical methods of eliminating critical alignment procedures and increasing effective switching speed are explained.
Abstract: A method of obtaining high peak power pulses from a ruby laser oscillator by controlling the resonant cavity Q with a spinning reflector technique is described. Basic principles are discussed. A theory regarding the multiple pulse problem of slow Q switching is presented. Practical methods of eliminating critical alignment procedures and increasing effective switching speed are explained. Experimental data relating to the effect of the parameters of cavity output transmission, crystal temperature, pump energy, reflector separation and spinning speed upon laser power and energy are presented. Results of experiments at temperatures ranging from -20°F to 140°F are given. Application of the spinning reflector technique to optical ranging is discussed. Described is an experimental rangefinder designed and fabricated to show feasibility of the technique for military application.
23 citations
TL;DR: In this paper, the authors derived formulas for the variances of maximum likelihood estimates of azimuth and elevation by dense, discrete and discrete-continuous apertures for the strong signal case.
Abstract: By extending the results of Kelly, Reed, and Root, formulas are derived for the variances of maximum likelihood estimates of azimuth, and azimuth and elevation, jointly, by dense, discrete and discrete-continuous apertures for the strong signal case. The accuracy of angle measurements depends upon 1) total signal energy captured by the aperture, 2) the mean-square aperture size, 3) carrier frequency, 4) the mean-square signal bandwidth. Mean-square quantities are the second moments about the centroids. The actual signal form and aperture form do not matter, except as they affect the mean-square quantities. When joint estimates of azimuth and elevation are made, the errors are generally coupled. Minimum variances are obtained when the errors are uncoupled. This condition is obtained, in the narrowband case, when the two-dimensional illumination function is factorable into the product of one-dimensional functions. The formulas for the dense and discrete apertures are identical in form, the various factors being discrete or continuous analogs of one another in which integrations are replaced by summations. The formulas for the discrete-continuous array differs in form by the presence of terms which reflect the anisotropy of the beam patterns.
15 citations
TL;DR: A brief historical summary is followed by a review of current observations of Jupiter's decametric radiation, with particular attention given to the time structure and statistical properties of the emission as mentioned in this paper.
Abstract: A brief historical summary is followed by a review of current observations of Jupiter's decametric radiation. Particular attention is given to the time structure and statistical properties of the emission, and several important deficiencies in our observational knowledge are pointed out.
13 citations
TL;DR: Practical methods, suited to digital computers, are presented for the formulation, reduction, and combination of systems in state-space form, with the emphasis upon the ease of handling large, complex problems afforded by the systematic format of the state- space representation.
Abstract: Practical methods, suited to digital computers, are presented for the formulation, reduction, and combination of systems in state-space form. Formulation is illustrated in two ways. The coefficients of a linearized set of equations describing a simple superheater are entered directly in the matrices of the state-space equations. Transfer functions of a control system are decomposed into first-order differential equations and put in the same form. Reduction to standard state-space form is accomplished by matrix inversion and by signal-flow graph manipulation that is equivalent to inversion by partitioning. Composite systems are formed from subsystems that are in either reduced or unreduced form. The emphasis is upon the ease of handling large, complex problems afforded by the systematic format of the state-space representation. Key words are combination, composite system, control design, digital computer, formulation, linear, matrix, matrix inversion, reduced system, reduction, signal-flow graph, state-space, superheater, unreduced system.
12 citations
Abstract: The general criteria for the operational performance of laser ranging systems are considered in quantitative terms with emphasis being placed on the optimization of systems which must meet specific operational requirements. The entire range-determining process is discussed on a statistical basis and the target detection capabilities of a system are defined in terms of the relative probabilities of recording real and false targets. Within this analysis appears a detailed discussion of all contributing noise sources, these being reduced to a fundamental noise source for two specific systems which transmit at different frequencies. A comparison is then made between the relative power requirements of the two systems performing the same task. In the case of some pulsed gas lasers, the pulse duration is somewhat long, thus necessitating a compromise between range resolution and maximum range capability. The relationship between these parameters is discussed in detail. In addition, a technique is proposed whereby the resolution is varied as a function of target return. This technique employs a multiple pulse transmitter and automatically optimizes its resolution and range capabilities.
12 citations
TL;DR: The characteristics of parametric amplifiers, including effective input noise temperature, bandwidth, stability, and gain compression, are discussed in this article, where a liquid nitrogen cooled L-band unit for a radio astronomy observatory and a three-channel unit for satellite vernier auto track system are described.
Abstract: The characteristics of parametric amplifiers, including effective input noise temperature, bandwidth, stability, and gain compression are discussed. Two specific amplifiers, a liquid nitrogen cooled L-band unit for a radio astronomy observatory, and a three-channel unit for a satellite vernier auto track system, are described, and the characteristics of these amplifiers are presented.
TL;DR: In this article, principal antenna parameters which are useful in characterizing the electrical performance of radio-telescope antennas are defined and relations between them are established and the application of these parameters to radio astronomical measurements is discussed.
Abstract: Principal antenna parameters which are useful in characterizing the electrical performance of radio-telescope antennas are defined and the relations between them are established. The application of these parameters to radio astronomical measurements is discussed.
TL;DR: In this paper, the nature of Lambda -doublet levels of O16H1 is reviewed in an attempt to clarify the origin of the Lambda-doublet lines.
Abstract: The detection of the ² \Pi_{3/2}, J=3/2 \Lambda -doublet lines of O16H1at 1665.36 Mc and 1667.40 Mc has provided radio astronomy with a second spectral line for investigation and has already given rise to a number of significant results. In this paper the nature of \Lambda -doublet levels are reviewed in an attempt to clarify the origin of the OH lines. The results of the OH observations are presented and the distinction between absorption and emission experiments is discussed in terms of the importance for the OH lines. The frequencies of the astrophysically important OH transitions in various molecular states and isotopic species are given and their detection possibilities are briefly discussed. Detection of the ^{2}Pi_{3/2}, J=3/2 transitions of O18H1appears possible with current techniques. Radio molecular lines of SH, SiH, CH, CN, and NH are also discussed.
TL;DR: In this article, the beam efficiency of an antenna is defined as the ratio of the power radiated within the main beam to the total power radiated by the antenna, where the beam power is proportional to the edge-to-center amplitude ratio.
Abstract: The beam efficiency of an antenna may be defined as the ratio of the power radiated within the main beam to the total power radiated. The beam efficiency is derived for ideal rectangular and circular apertures, as a function of the edge-to-center amplitude ratio. Random phase errors are assumed to exist across the aperture. Various types of feeds for parabolic reflectors are also considered in relation to the fraction of power which the feed directs into the paraboloid. A primary limitation on the beam efficiency of a paraboloid is shown to be produced by the surface roughness.
TL;DR: The most important result of the observations is the discovery that the temperature at the surface of Venus, beneath the clouds, is greater than 600\deg K as mentioned in this paper, which can be interpreted in terms of the physical characteristics of the subsurface material.
Abstract: Thermal radio radiation has been observed from the moon, Mercury, Venus, Mars, Jupiter, and Saturn. The most important result of the observations is the discovery that the temperature at the surface of Venus, beneath the clouds, is greater than 600\deg K. The thermal radio radiation from the moon comes from beneath the surface and gives information about the temperature distribution and variation which can be interpreted in terms of the physical characteristics of the subsurface material. This also should apply to the planets with thin atmospheres. The thermal radio radiation from Jupiter should give information about the temperature distribution in the extensive absorbing atmosphere, but the intensity of the thermal radiation is confused by the nonthermal radiation of the radiation belts and cannot be accurately specified until more observational data are available.
TL;DR: A review of radio astronomy development starting with Jansky at 15m wavelength and progressing to 30, 60, 144, 576, and 2100 m is given in this paper, with a comprehensive list of references to the literature along with four figures.
Abstract: A review is made of radio astronomy development starting with Jansky at 15-m wavelength and progressing to 30, 60, 144, 576, and 2100 m. Electromagnetic wave propagation through the ionosphere by the O, X, Z , and Y modes including various aberrations is discussed. Methods of overcoming atmospherics are outlined. Preliminary findings at hectometer waves and the cosmological implications are mentioned. The different outlook upon the structure of the universe appears to be a more enticing aspect of the study than details about the contents of the Milky Way. Equipment technology is entirely omitted. A comprehensive list of references to the literature is included, along with four figures.
TL;DR: A linear programming model can be used to plan new generation and transmission systems and the results include marginal cost estimates and analysis of the sensitivity of the solution to various given data and parameters, as well as a description of the optimal system.
Abstract: A linear programming model can be used to plan new generation and transmission systems. The instance described is a model for the Pacific Coast region of the United States for the years 1965 through 1980. The method allows simultaneous optimization, at a high level of aggregation, of all decision variables relevant to this geographic space and time period. The results include marginal cost estimates and analysis of the sensitivity of the solution to various given data and parameters, as well as a description of the optimal system. The strengths and limitations of linear programming in this use are discussed.
TL;DR: The role of radio and radar astronomy in space exploration is discussed and compared with present and future techniques that use electromagnetic waves of all lengths, gravity waves, atomic particles, etc..
Abstract: The role of radio and radar astronomy in space exploration is discussed and compared with present and future techniques that use electromagnetic waves of all lengths, gravity waves, atomic particles, etc. A brief description of the universe is then given with the aid of a series of scale drawings, and the possible ranges of the different techniques are considered. The place of space probes and manned space travel in space exploration is also mentioned. It is pointed out that radio astronomy is not only the most promising technique presently available for observing the most distant parts of our universe but it may be the only one.
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TL;DR: The methodology of planning systems to meet stated goals in an optimum manner while recognizing all pertinent constraints is being given increasing attention by systems engineers as mentioned in this paper, and significant progress in system planning has been achieved to date in the electric utility industry.
Abstract: The methodology of planning systems to meet stated goals in an optimum manner while recognizing all pertinent constraints is being given increasing attention by systems engineers. In the electric utility industry the greatly increased complexity of the systems required to meet anticipated load growth, the advent of large-scale interconnection of systems, increasing investment costs and the pressure for continued economy of service have necessitated continuing efforts to achieve more comprehensive and exacting approaches to system planning. Significant progress in system planning has been achieved to date in the electric utility industry. Integrated digital computer programs have been devised which permit the modeling of the technical and economic performance of future system design alternatives and aid the system planner in obtaining an optimum total system beginning with the sources of fuel and ending with the final delivery of power to the customer. By the methods presented in this paper the total present worth cost of various alternative system designs may be readily obtained. Limited work has been undertaken concerning the direct optimum synthesis of a system plan. The major difficulty in direct synthesis arises from the complex interrelationships of the variables and the high dimensionality of the problem.
TL;DR: In this article, a theoretical solar model is developed to help explain some of the characteristics of the solar echo, and a system sensitivity increase of at least 10 dB is needed in order to overcome the effects of non-Gaussian noise during times of solar activity, and an increase of 30 db is needed to study the echo from the quiet sun without signal integration.
Abstract: The study of the sun by radar which was begun less than five years ago should become a valuable supplement to the study, by other methods, of the sun and interplanetary space. High powered transmitters and large antennas are required to detect a solar echo. Frequencies less than 50 Mc should be optimum, primarily because of increasing coronal absorption with increasing frequency. Routine observations were begun by the Lincoln Laboaratory of the Massachusetts Institute of Technology in April, 1961, at a site near El Campo, Texas. Observations since that time have been made on about 200 days per year. The transmitter has an average power output of 500 kw and operates at a frequency of 38.2 Mc. The system includes two cross-polarized antennas consisting of large arrays of dipoles. These antennas have maximum gains of 33 and 36 db. The received solar echo is usually 20 to 30 db below the solar noise and signal integration is required to detect the echo. The average measured solar radar cross section is approximately equal to that of the projected area of the photosphere although there are large fluctuations about the mean. Some possible reasons for these variations in cross section are discussed. The Doppler spreading of the solar echoes varies between 20 and 70 kc and is apparently due to mass motions on the sun. These indicated mass motions are large enough to affect the coronal temperature measurements made by the emission-line broadening method. The peaks of these spectra are usually shifted in the positive Doppler direction by about 4 kc. This shift implies a solar wind at the level of reflection. A theoretical solar model is developed to help explain some of the characteristics of the solar echo. Suggestions are made for improved equipment and procedures that should result in more significant solar radar results in the future. A system sensitivity increase of at least 10 db is needed in order to overcome the effects of non-Gaussian noise during times of solar activity, and an increase of at least 30 db is needed to study the echo from the quiet sun without signal integration.
TL;DR: The pulsed helium-neon gas laser has provided pulse power more than three orders of magnitude above the average power afforded by CW operation and analyses of the power-limiting factors show that still greater increases may be expected.
Abstract: The pulsed helium-neon gas laser has provided pulse power more than three orders of magnitude above the average power afforded by CW operation. Analyses of the power-limiting factors show that still greater increases may be expected. By increasing the size of the laser tube several times, by optimizing the gas ratio and pressure, by optimizing reflectivity and transmissivity of the reflecting mirrors, and by controlling the shape and application of the exciting voltage pulse, peak power outputs in the kilowatt range are theoretically possible. A power of 100 watts has been achieved in the laboratory at pulse rates up to 250 cps. Such a result brings the gas laser out of the low power category and into the intermediate power range. The results of range calculations show that 100 w pulse power will provide a radar range of approximately 10 km against a target having a diffuse reflectivity of 0.1, and a range of over 100 km with a cooperative target. Against a bright cloud background only the cooperative target can be used. The range will then be reduced to approximately 20 km. An automatic tracking radar system has been synthesized utilizing the pulsed gas laser as a transmitting component. A brief parametric analysis has beem made and some of the advantages of the optical radar over its microwave counterpart have been outlined.
TL;DR: Ionospheric scintillations are functions of both magnetic conditions and of the subionospheric latitudes of the irregularities; they are observed at zenith at the geomagnetic latitude of the Sagamore Hill Radio Observatory (54°).
Abstract: Observations of two radio stars, Cygnus A and Cassiopeia A, and of two satellites, Cosmos I and Transit 4A, have yielded data on lower and upper atmospheric irregularities. The frequencies studied have included 20 Mc, 40 Mc and 54 Mc for satellite transmissions, and 30 Mc to 3000 Mc for radio star signals. The antennas used have ranged from a dipole to a 150-foot parabola. The irregularities in refractive index in the lower atmosphere produce amplitude fluctuations up to several times average with a fading rate of 3 to 0.5 per minute while ionospheric amplitude fluctuations can increase several decibels, with rates from 1 to 60 per minute. Lower atmosphere scintillation rates increase as the elevation angle increases and generally disappear above 5\deg of elevation. During intense magnetic storms, the ionospheric scintillation rate is a function of wavelength in the UHF range. Ionospheric scintillations are functions of both magnetic conditions and of the subionospheric latitudes of the irregularities; they are observed at zenith at the geomagnetic latitude of the Sagamore Hill Radio Observatory ( 54\deg ). Using spaced receivers, heights of single irregularities have ranged from about 100 to 600 km and representative sizes from about 0.1 to 4 km. Irregularities constitute the prime factor affecting the level, phase and angle of arrival of signals propagated through the auroral regions.
TL;DR: In this article, a mathematical technique has been developed for obtaining algebraic expressions for the minimum cost, as well as for the optimum design parameters in terms of the physical parameters of the system and of various unit costs, such as electric power and fuel costs.
Abstract: Many types of equipment have two costs: the cost of the work potential dissipated by the equipment in operation, and its initial capital cost. The correct design minimizes the total cost. A mathematical technique has recently been developed for obtaining algebraic expressions for the minimum cost, as well as for the optimum design parameters in terms of the physical parameters of the system and of various unit costs, such as electric power and fuel costs. The present paper illustrates this mathematical optimization technique through its application to the design of a counter-flow heat exchanger. Algebraic expressions are obtained for the following design parameters: flow velocities and surface area per unit rate of heat exchanged. This mathematical technique is equally applicable to design problems where properties other than cost are to be minimized, such as weight.
TL;DR: The role of radar backscatter observations in ionospheric studies is outlined in this article, where theoretical developments are described that form the basis for ground-based measurements of electron density, electron temperature, ion temperature, and ionic composition at ionosphere heights, Observations of the first three parameters have been successful.
Abstract: The role of radar backscatter observations in ionospheric studies is outlined. The theoretical developments are described that form the basis for ground-based measurements of electron density, electron temperature, ion temperature, and ionic composition at ionospheric heights, Observations of the first three parameters have been successful. Observation of the fourth parameter, ionic composition, is a challenging problem and is being attempted.
TL;DR: The purpose of this paper is to determine the search or acquisition time required by the two terminals to achieve the desired state of knowledge whereby the transmit-receive beams of both terminals are pointed in the required directions, signals are mutually recognized and the communication link is thereby established.
Abstract: It is desired to establish a communication link between two separated transmit-receive terminals, each having narrow beamwidths and specified uncertainty as to relative angular locations. To achieve the communication link the narrow beams must point directly at each other. The purpose of this paper is to determine the search or acquisition time required by the two terminals to achieve the desired state of knowledge whereby the transmit-receive beams of both terminals are pointed in the required directions, signals are mutually recognized and the communication link is thereby established. The acquisition time is a random variable and can thus be described in terms of an expected value and standard deviation. Markov chain concepts are employed to derive equations for the expected acquisition time in terms of system parameters such as relative angular uncertainty, beamwidth, probability of detection of a signal in noise, false alarm probability, etc. Single as well as multiple receive beam systems are considered. Curves relating the expected acquisition time to probability of detection and pointing probability are presented.
TL;DR: In this article, the authors present several special techniques and devices which are required to make these measurements, as well as some of the results of applying these techniques to Venus, Mars, Mercury, and Jupiter.
Abstract: Planetary radar astronomy's greatest handicap is the extremely feeble power content of an echo. This echo is always masked by relatively strong background noise so that special signal processing is required. The basic task is the detection and measurement of the echo power. However, when the signal strength is greater than the requirements of simple detection, it is desirable to measure the power distribution in time or in frequency. When the signal is still stronger, it is possible to divide the power into the two dimensions of time delay and frequency shift simultaneously, and thus produce a radar "map" of the target. Some of the special techniques and devices which are required to make these measurements, as well as some of the results of applying these techniques to Venus, Mars, Mercury, and Jupiter, are described. There are several groups working in this field and the author has stressed the work at the Jet Propulsion Laboratory merely because of his familiarity with it.
TL;DR: It has been shown how some problems and concepts associated with the theory of Turing machines can be applied to engineering system and vice-versa.
Abstract: A formal system is introduced which is capable of representing a universal Turing machine. This enables the input, state-output representation of the computing systems that allows the study on a unified basis of the larger systems involving computer-like subsystems. It has been shown how some problems and concepts associated with the theory of Turing machines can be applied to engineering system and vice-versa. This has been made possible by using the proposed formal system.
TL;DR: A unified view of the large amount of progress which has been made in the analysis of systems such as radar, communications, imaging systems, etc., is presented and some of the solutions presented are presented.
Abstract: A unified view of the large amount of progress which has been made in the analysis of systems such as radar, communications, imaging systems, etc., is presented. The basic theory of complex parameter systems and the role of phase lock in such systems is given in Section II. Performance limitations due to phase errors, stochastic delays, and clipping are discussed in Sections III and IV. Section V gives some results of ifitering for the modulus of a complex signal, and Section VI treats some problems in scatter communications. The following are some of the solutions presented. Phase lock provides a factor-two improvement in signal-to-noise ratio in coherent receivers. If r(x) denotes random deviation from constructing a straight antenna and ? is the standard deviation of d2r/dx2, then there exists a Gaussian illumnation which provides a radius of gyration beamwidth of ???/2?. Hard limiting of radar or analog communication signals prior to processing in an optimum receiver results in an rms error in signal estimation of 32 per cent in the presence of Gaussian statistics. With Gaussian statistics, the processor which minimizes E(|Jf-h|2) where f is signal and h is system output (where additive noise is present) also minimizes E [(|f|2-|h|2)2] save for a correction of mean value which is required in the latter case. In the section on scatter communications, the relation between "cloud size statistics" and coherence bandwidth is presented along with the performance gain available through the use of space diversity in the receiving system.
TL;DR: The expected philosophy in the future trend for energy conversion on a large scale is outlined in this paper and a scheme is described which outlines a method of searching for new conversion processes.
Abstract: The expected philosophy in the future trend for energy conversion on a large scale is outlined in this paper. Following a brief review of the basic concepts of irreversible thermodynamics a scheme is described which outlines a method of searching for new conversion processes. Some examples are then given to demonstrate the method.