R-3 Repository :: Browsing by Author "Pfeiffer, Paul E."

Browsing by Author "Pfeiffer, Paul E."

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A capacitor buffer memory
(1962) Schutz, Theodore Charles; Graham, Martin; Pfeiffer, Paul E.; Rorschach, Harold E., Jr.
Digital information may be stored as a charge on a capacitor if suitable switches are used on the input and output lines. Characteristics of neon glow lamps (ionized from an external radio frequency source) pertinent to application in a capacitor store buffer memory were investigated. The results of this investigation and application of the results to the construction of a 64 bit buffer memory are discussed.
A coding system using hybrid tree-block codes
(1965) Ong, Chung-Yen; Pfeiffer, Paul E.
This paper is devoted to introducing an idea about coding and decoding theory. A compromise between tree codes and block codes, a hybrid tree-block code, is introduced. The concepts of discarding all improbable sequences in sequential decoding and decoding a whole block at a time in block decoding are used in this code. The structure of a hybrid tree-block code and its decoding scheme are discussed. The probability of error and the number of decoding operations are considered, and a comparison with block codes and tree codes are also considered.
A Computational Note on Markov Decision Processes Without Discounting
(1987-07) Pfeiffer, Paul E.; Dennis, J.E. Jr.
The Markov decision process is treated in a variety of forms or cases: finite or infinite horizon, with or without discounting. The finite horizon cases and the case of infinite horizon with discounting have received considerable attention. In the infinite horizon case, with discounting, the problem either receives a linear programming treatment or is treated by the elegant and effective policy-iteration procedure by Ronald Howard. In the undiscounted case, however, a special form of this procedure is required, which detracts from the directness and elegance of the method. The difficulty comes in the step generally called the value-determination procedure. The equations used in this step are linearly dependent, so that the solution of the system of linear equations requires some adjustment. We propose a new computational procedure which avoids this difficulty and works directly with the average next-period gains and powers of the transition probability matrix. The fundamental computational tools are matrix multiplication and addition.
A fifty kilocycle per second triangular wave generator
(1963) Silvus, Howard Stanley; Pfeiffer, Paul E.
The development of a fifty kilocycle per second triangular wave generator is discussed. Some of the possible applications for such a device are considered, as are a number of different methods for accomplishing the desired result. Three of these methods are considered in some detail, and the passive RLC integrator circuit proves to be the best of those investigated. A circuit for a self-contained fifty kilocycle per second triangular wave generator employing semiconductor active elements throughout is given. A mathematical analysis of the idealized RLC integrator circuit is provided. Numerical calculations based on this analysis are compared with values obtained from measurements on the actual circuit, A special linearity test is described, and measurements obtained from this test are compared with the calculated linearity based on ideal conditions. The results of the tests on the subject circuit showed that it will generate a fifty kilocycle per second triangular wave of plus or minus one percent linearity, 0.1 percent amplitude stability, and peak-to-peak output voltage of about thirteen volts.
A jump-search procedure for sequential decoding systems
(1967) Ho, Ching-quo; Pfeiffer, Paul E.
The introduction of the concept of sequential decoding by Wozencraft has opened up the possibility of more efficient decoding search procedures than those available with block code.. The purpose of this study is to try to improve the decoding scheme proposed by Pfeiffer and Lin. Because of the group property of the code, we do not have to search every branch when the tentatively decoding path has violated the threshold function. If the errors occur at 2nd, 3rd branches, we connect the 1st and 4th branches. By jumping over the errors, a correct path can be obtained. This article describes the use of the jumping method, according to the group property of the code word, in order to minimize the decoding operation.
A low frequency oscillator
(1953) Kwei, Man Wei; Pfeiffer, Paul E.
A rapidly responding narrow band infrared gaseous CO_ analyzer for physiological studies
(1960) Baker, Lee E; Pfeiffer, Paul E.
A report on an investigation of a commutated magnetometer detector
(1949) Badger, Algernon S; Pfeiffer, Paul E.
The subject of this investigation is a commutated rotating coil magnetometer element. One detector with quadrature sets of brushes could be used to align a second element with the total earth's field. It was lay contention that a commutated detector with a suitable filter and contact-modulated d-c amplifier would reduce the noise and stray pick-up considerably over existing design and simplify the application of a servomechanism as well. In order to determine the feasibility of such a device, the design and construction of the commutated detector, filter and contact-modulated amplifier were necessary. The armature consisted of 39 coils of 150 turns each of enameled no. 34 B. & S. copper wire spaced by fiber separators protruding from a luclte core. The Incite cylinder and copper coffiautator were force fit on a brass shaft supported by non-magnetic copper-beryllium ball bearings, Son-magnetic brush rigging and supports were used with the brush rig mounted so it could be rotated and the angular deflection read on a scale. An aluminum pulley was mounted on the shaft to drive the armature by means of a long cord belt and an oscillograph drive motor. Data taken to evaluate the relation between brush axis angle and output voltage of the amplifier. The axis of the armature was placed perpendicular to the horizontal component of the earth’s field and the rotor driven at 1600 RPM. Readings were taken of the amplifier output voltage and angular scale deflection over the Interval from zero output to saturation voltage on both sides of the zero position. These readings were checked and rechecked over a period of thirty minutes with no difference observed greater than the possible error in scale readings. The results of the data show clearly that the output voltage is linear with the angular change over the small interval near zero output. The magnitude of voltage developed at the 0.3535 degree limits desired is much greater than the inherent noise and is easily capable of controlling a servo system.
A search algorithm for sequential decoding systems
(1965) Wu, Weihong; Pfeiffer, Paul E.
The introduction of the concept of sequential decoding by Wozencraft has opened up the possibility of more efficient decoding search procedures than those available with block codes. The purpose of this study is to improve the search procedures proposed by Pfeiffer and Lin. We show that under most error conditions it is not required to begin the search at the earliest segment in the br-unit indicated by the multiple threshold test. An improved estimate of the probability of correcting an error in a br-unit is given. A new backup procedure and a modified threshold for discard make possible a more efficient search for the best path.
A servomechanism pantagraph
(1952) Whitaker, Thomas Norman; Pfeiffer, Paul E.
An analytical study of a space frame
(1960) Leach, Richard Peter Parton; Thibodeaux, Murphy H.; Pfeiffer, Paul E.; Holt, E. C.
An application of analog computer techniques to the problem of interpretation of the contact log
(1957) Nall, Arthur E; Pfeiffer, Paul E.
It is hoped that the following report may serve as the groundwork or basis for further applications of analog computer techniques to the field of electrical well logging interpretation. The author feels that this type of semiautomatic interpretation can be invaluable both as an exploratory tool and as a labor saving device in the interpretation of logs. From the exploratory view point, various combinations of mud resistivity, mud cake resistivity, and formation resistivity, may be tried in a matter of minutes to simulate a log for the purpose of experimental interpretation; while from the labor saving view point, countless hours of point by point tabulation of data may be saved by a continuous analog solution. The particular emphasis of this report deals with interpretation of the Contact Log, but the author feels that this same approach may be applied to any number of the other electrical logs now being run commercially. The author wishes to express his appreciation at this time to the Electrical Engineering Department of The Rice Institute for its cooperation in making available an analog computer so that the efforts of this research might be tried. In particular, the author wishes to thank Dr. Paul E. Pfeiffer for his constant guidance and suggestions, and the Halliburton Oil Well Cementing Company for its generous donation of time and information in making this investigation possible.
An investigation in automatic analysis of the galvanic skin response
(1961) Edwards, Robert J; Pfeiffer, Paul E.; Baker, Lee E.; Campbell, Wayne
As an individual thinks, makes simple Or complicated judgements and experiences emotions, his physiology undergoes subtle or profound changes reflecting the close relationships between physiological and psychological processes. Many of the physiological processes manifest themselves as electrical activity in the human body and are conveniently measured by present day electronic techniques. Studies a human behavior are making increasing use of changes in these bioelectric potentials to indicate changes psychological processes. Therefore, present day investigators find themselves studying many and various aperiodic waveforms of the bioelectric potentials. The large amount of data recorded as bioelectric potentials presents a complex problem in analyzing and abstracting the significant changes that may indicate changes in psychological processes. In this investigation, an automatic analysis system is, developed for one of the frequently used bioelectric potentials, the Galvanic Skin Reflex (GSR). The analysis process is orientated toward relating parameters of Galvanic Skin Reflex activity to an individual's degree of neurophysiological arousal and to measures of group interactions among several individuals.. The analysis process was carried out with an analog computer and was completely automatic. Use a the analog computer gave a versatile and convenient method for experimenting with the data to determine what parameters of the GSR activity are significant in reflecting psychological changes, what parameters are suitable for automatic analysis, and finally to formulate the requirements for building a GSR analyzer.
An investigation of a condenser microphone as a pressure transducer
(1954) Schwartz, Robert, 1950-; Pfeiffer, Paul E.
The device described is a preasure-sensitive transducer. commercially available condenser microphone, a Stephens model C-1 was used as a capacitor manometer. The instrument was developed for use in breath velocity studies where pressures encountered are thousandths of pounds per square inch. A study of the literature indicated that a number of methods have been used to obtain information breath velocity studies of which the capacitor manometer is one of the most promising. Its use makes possible high sensitivity and short rise-time which is important in providing useful information in respiratory studies. The method employed is based on the um of the microphone as a variable load impedance in a cathode follower driven by a crystal controlled oscillators The voltage impressed across the microphone in the range of 8 is then detected and emplified. A dummy channel, an electrical equivalent of the microphone and its cable, is used in a balancing arrangement to develop a variable d-e centering voltage for the pen recorder used with this instrument and to provide the means for an output balanced to ground. A voltage-regulator power-supply is used to assist in attaining high useful sensitivity by reducing drift and ripple attibutable the power supply. A number of pen recorded trace of breathing are included. The circuitry, its development, testing, and operation is discussed addition to suggestions for additional work and further study. ,
An investigation of a criterion for the optimum transient response of servo-mechanisms
(1957) Tasini, Betsalel; Pfeiffer, Paul E.
A new criterion for the optimum transient response or linear systems (in particular regulating systems) is discussed and investigated. The criterion is evaluated analytically for systems of the second and third order. Auxiliary apparatuses which were needed for experimental testing of the criterion are discussed and evaluated. The investigation concludes of the unsuitability of the criterion and its poor merits.
An investigation of analog similation of magnetic amplifier circuits
(1958) Harker, Homer Jean; Pfeiffer, Paul E.
An investigation of certain problems in the use of sample cores in analog simulation of magnetic amplifier circuits
(1958) Pope, Herman Lloyd; Pfeiffer, Paul E.
In order to establish the conversion factors between an actual circuit and its computer simulation, the simple half wave magnetic amplifier-circuit was used. The Computer simulation of this circuit requires three operational amplifiers, with the associated scaling factors involving all of the variables of the actual circuit core material area, mean length of path, and number of turns. In addition to establishing these scaling factors in the computer circuit, these variables affect the inductance-resistance ratio. of the magnetic amplifier core and are used to determine the resistance to be added in the test core circuit so-that the L/R of the test core matches that of the actual core being simulated. Computer circuits were set up to simulate several actual circuits having cores with size and number of turns different from those of the test core of the computer circuit. Comparison of actual circuit data with simulated circuit data showed considerable difference, and thia difference was found to be due to the difference in losses of the cores. It was necessary to scale the computer circuit data by a factor proportional to the ratio of the losses of the two cores. This factor was determined from a comparison of the B-H loops of the two cores, since the width of the B-H loop is proportional to the losses in the core. It should be noted, in connection with this part of the study, that the geometry of the core is of some importance in the simulation process. Cores having different outside to inside diameter ratios have B_H curves which differ somewhat in slope. Although the half-wave circuit serves to establish the necessary conversion factors in the simulation process, more complicated circuits should be studied to check the accuracy of the derived relationships. No data was taken on other circuits, due to time and computer limitations, but two more complicated circuits and their simulation are described, and recommendations for further studies are given in this report.
Analysis and synthesis of burst-error-correcting recurrent codes
(1965) Epley, Arthur Wilson; Pfeiffer, Paul E.
In this research, recurrent codes used to correct bursts of error have been studied in detail. A mathematical formulation of these codes is presented which shows them to be convolutional codes. The encoding and decoding procedures are presented mathematically, and practical methods of implementation are given. The work of Wyner, Hagelbarger, and Berlekamp is reviewed and discussed. A new class of codes with low transmission rate is presented, and the merits of these codes are discussed. A procedure for construction of a generalized code from known codes is presented, and two theorems concerning this construction are proved. Finally, the advantages of various codes with different rates are examined carefully.
Boolean function analyzer
(1960) Montgomery, William Calvin; Pfeiffer, Paul E.
Construction of universal bundles
(1979) Thongyoo, Sutep; Curtis, Morton L.; Hempel, John; Pfeiffer, Paul E.
By a n-universal bundle, we mean a principal fiber bundle such that the bundle space is (n-1)-connected. The present paper shows that for a suitable base space X (namely an arc-wise connected space which can be covered by a countable number of contractible open sets) there exists an infinity-universal bundle over X.

Browsing by Author "Pfeiffer, Paul E."

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