Showing papers by "Naval Postgraduate School published in 1969"
TL;DR: The main result is that the sets of trees generated by regular systems are exactly those that are accepted by tree automata.
Abstract: Trees are defined as mappings from tree structures (in the graph-theoretic sense) into sets of symbols. Regular systems are defined in which the production rules are of the form Φ → ψ , where Φ and ψ are trees. An application of a rule involves replacing a subtree Φ by the tree ψ . The main result is that the sets of trees generated by regular systems are exactly those that are accepted by tree automata. This generalizes a theorem of BUchi, proved for strings.
247 citations
TL;DR: Fine scale measurements of the vertical temperature profile in an Arctic water column show the presence of several cascaded isothermal layers.
Abstract: Fine scale measurements of the vertical temperature profile in an Arctic water column show the presence of several cascaded isothermal layers. Layers between the depths of 300 anid 350 meters range from 2 to 10 meters in thickness, while the temperature change between adjacent layers is approximately 0.026 degrees C. The individual layers are isothermal to within +/- 0.001 degrees C.
114 citations
TL;DR: Calorimetric, dielectric, and electrocaloric measurements have been performed on single-crystal samples of K${\mathrm{H}}_{2}$P${O}}_{4}$ in the neighborhood of the ferroelectric phase transition, and show that the transition is of first order as discussed by the authors.
Abstract: Calorimetric, dielectric, and electrocaloric measurements have been performed on single-crystal samples of K${\mathrm{H}}_{2}$P${\mathrm{O}}_{4}$ in the neighborhood of the ferroelectric phase transition, and show that the transition is of first order, with a discontinuous entropy change of $({{0.0456}_{\ensuremath{-}0.0059}}^{+0.0045})R$ and a change in the dielectric constant by a factor of 2. Calorimetric measurements in applied electric fields were also carried out, and show that the effect of an applied field is to shift the transition to higher temperatures and to broaden it. Calorimetric measurements on K${\mathrm{D}}_{2}$P${\mathrm{O}}_{4}$ are reported which can be combined with previously reported results to give the heat capacity for this material in the range 80-280\ifmmode^\circ\else\textdegree\fi{}K. Comparison of the heat capacity of K${\mathrm{H}}_{2}$P${\mathrm{O}}_{4}$ and its deuterated isomorph allows estimates of the lattice heat capacity to be made. From this estimate, the entropy change associated with the ferroelectric transition is found to be $(0.400\ifmmode\pm\else\textpm\fi{}0.036)R$ for K${\mathrm{H}}_{2}$P${\mathrm{O}}_{4}$ and $(0.457\ifmmode\pm\else\textpm\fi{}0.034)R$ for K${\mathrm{D}}_{2}$P${\mathrm{O}}_{4}$. A significant feature of the comparison is the lack of evidence for the heat-capacity contribution above the transition predicted by theories of the Slater type. Comparison of the calorimetric data with the modified Slater theory due to Silsbee, Uehling, and Schmidt shows that this theory describes K${\mathrm{D}}_{2}$P${\mathrm{O}}_{4}$ better than it does K${\mathrm{H}}_{2}$P${\mathrm{O}}_{4}$. The differences between the theory and experiment are of the type predicted by the modifications of the theory which include tunneling motion of the protons.
49 citations
TL;DR: In this article, the authors reviewed the existing measurements and theories of the low-temperature thermal properties, heat capacity, and thermal conductivity of polymers with particular attention paid to the differences between partly crystalline and amorphous polymers.
Abstract: The existing measurements and theories of the low-temperature thermal properties, heat capacity, and thermal conductivity of polymers are reviewed with particular attention paid to the differences between partly crystalline and amorphous polymers. The most striking feature of the low-temperature heat capacity of polymers is that in the liquid helium temperature range the heat capacity does not depend upon the cube of the temperature as for other solids. Further, only well below 1°K does the heat capacity approach the value predicted on the basis of the sound velocity. This behavior indicates the presence of a small number of low-frequency modes of vibration in the frequency spectrum. The fact that such anomalous behavior seems linearly related to the crystallinity implies that this behavior is associated with the amorphous structure, perhaps with motions of pendent groups within cavities formed in the amorphous structure. The thermal conductivity of semicrystalline and amorphous polymers differs ...
40 citations
TL;DR: When separate 100(1-alpha) percent confidence intervals on two population means overlap, the means may or may not be significantly different at the 100-alpha percent level as mentioned in this paper.
Abstract: When separate 100(1-alpha) percent confidence intervals on two population means overlap, the means may or may not be significantly different at the 100-alpha percent level. This phenomenon is explored analytically and numerical examples are given...
35 citations
32 citations
TL;DR: In this article, the direction and magnitude of the mean meridional circulation of the polar night vortex were investigated by employing a heat budget method, which revealed that the mean cell operates to produce rising motion over the polar regions before, during, and after the breakdown period.
Abstract: In order to gain a greater understanding of the physical processes acting in the lower stratosphere during a major breakdown of the polar night vortex, a computation of the direction and magnitude of the mean meridional circulation is performed by employing a heat budget method. This computation reveals that the mean cell operates to produce rising motion over the polar regions before, during, and after the breakdown period. The calculations show that horizontal eddy heat flux provides the predominant mechanism for the large temperature increases observed over the polar cap during the time of the vortex breakdown. As a supplement to the above computation, mean vertical velocities were determined with respect to a curvilinear coordinate system oriented along a line of maximum circulation intensity at 50 mb. The result showed that the mean cell operates in the direct sense prior to the major breakdown when measured relative to this curvilinear system.
24 citations
TL;DR: An electronic speech processor is described which provides an analog voltage output based on the difference signal between the first speech formant and the second, which was very good when the speech processor output was sampled and compared with previously recorded memory-stored data in a small digital computer.
Abstract: In the present age of scientific discovery, man has become more and more dependent on the use of electronic computers. As this powerful tool becomes more universally important in man's day-to-day existence, it becomes increasingly more annoying that he has to speak to it in its mode of communication, paper tape or punch cards; and not in his own, the spoken word. Even today in the very infancy of the computer age, the time required to do many computations is less than the time required to instruct the machine in how to do them. All this points to the need of a method of achieving machine recognition of speech. In this paper an electronic speech processor is described which provides an analog voltage output based on the difference signal between the first speech formant and the second. Machine recognition of numbers zero through nine was very good when the speech processor output was sampled and compared with previously recorded memory-stored data in a small digital computer.
20 citations
TL;DR: In this paper, local heat transfer coefficients in the fully established oscillating turbulent boundary layer over a flat plate were measured in the range of frequencies from 0.1 to 200 cps and amplitudes from 8 to 92 percent of the freestream mean velocity increases in local Nusselt numbers of 3 to 5 percent.
Abstract: Measurements of local heat transfer coefficients in the fully established oscillating turbulent boundary layer over a flat plate are reported. In the range of frequencies from 0.1 to 200 cps and amplitudes from 8 to 92 percent of the freestream mean velocity increases in local Nusselt numbers of 3 to 5 percent were found. It is concluded that substantial increases in local coefficients sometimes reported in oscillating flows of low standing wave ratio may be traced to reduced transition Reynolds numbers.Copyright © 1969 by ASME
20 citations
TL;DR: In this article, the average burning rates of a parametric series of aluminized propellants were determined in acceleration fields up to 1000 g using a combustion bomb mounted on a centrifuge.
Abstract: The average burning rates of a parametric series of propellants were determined in acceleration fields up to 1000 g using a combustion bomb mounted on a centrifuge. The propellant strands were burned at 500, 1000, and 1500 psia with the acceleration field directed normal and into the burning surface. Acceleration caused a time-dependent increase of as much as 100% in the burning rate of relatively slow-burning aluminized propellants. The relative amount of burning-rate increase for the various propellants was strongly dependent on the amount of aluminum retained on the propellant surface during burning. The burning rates of two very fast-burning propellants were found to be essentially accelerationindependent. OLID-PROPELLANT rocket motors are currently being used in applications which subject the metallized propellant grains to acceleration fields. The propellant burning rates increase appreciably when the acceleration field is imposed normal and into the burning surface.1'2 Postfire inspections of motors containing metallized propellants have revealed the presence of metal and/or metal oxide residue in the motor cases. The propellant burning-rate increase and the retention of residue appear to be interrelated. The review and abstracting of the literature on the effects of acceleration on solid-propell ant performance are presented in Refs. 3 and 4. Although progress has been made toward an understanding of some aspects of burning-rate augmentation in acceleration fields, it was believed that additional experimental studies with well-controlled propellant parameters would yield valuable insight. A parametric series of aluminized propellants was formulated to establish the importance of some of the propellant parameters that could be controlled to minimize the effects of acceleration. The objectives of this investigation were twofold. The first objective was to obtain the quantitative effect of acceleration on the burning rate of the propellants as a function of propellant composition, acceleration level, and time. The second objective was to obtain quantitative information on the amount of aluminum and/or aluminum oxide residue retained in the inhibitor case as a function of propellant -composition, acceleration level, pressure level, and propellant burning rate.
17 citations
TL;DR: In this paper, the authors convert a quadratic assignment problem with a nonconvex objective function into an integer linear program and then solve the equivalent integer program by a simple enumeration that produces global minima.
Abstract: We convert a quadratic assignment problem [1] with a nonconvex objective function into an integer linear program. We then solve the equivalent integer program by a simple enumeration that produces global minima.
TL;DR: In this article, a simple method of computing longwave radiative cooling in the troposphere associated with water vapor is described, which may readily be incorporated into a tropospheric numerical prediction model.
Abstract: A simple method of computing longwave radiative cooling in the troposphere associated with water vapor is described. The procedure may readily be incorporated into a tropospheric numerical prediction model. Radiation from ozone and carbon dioxide is not considered. However, influences of arbitrary vertical distributions of cloud and moisture are included. Average annual cooling rates along a meridional cross section are calculated for a cloudless atmosphere. The results agree fairly well with the total radiative cooling (longwave and shortwave) as given by Manabe and Moller except in the lower troposphere at low latitudes. Here shortwave absorption by water vapor is appreciable. The three-dimensional distribution of longwave radiative cooling is also computed in a case of a developing cyclone for comparison with that of release of latent heat. The largest cooling occurs at cloud top and can be a significant fraction of the amount of energy released as latent heat in the upper troposphere. Computa...
TL;DR: A dynamic programming model is presented for the optimal redundancy problem and the application of the generalized decomposition operator is used to develop a set of recursive relations for any mixed series and parallel system of modules.
TL;DR: In this paper, the authors investigated the effect of stress on thermoplastics, especially for polyethylene, and proposed a method to estimate the material activation energy, which is a measure of internal resistance to deformation.
Abstract: Although creep in thermoplastics, especially for polyethylene, has been investigated throughly, not too much information exists to establish activation energies at different stress levels by the application of high stress-level, short-time creep tests. Extrapolation of data to zero stress gives a true material activation energy which is a measure of internal resistance to deformation. Descriptions of specific creep parameters and equipment with a relatively simple phototube recording device are offered along with a discussion of results and recommendations for future fields of investigation.
TL;DR: In this article, the authors examined the temperature range of validity of the Landau expansion in the case of the calorimetric anomaly in KH2PO4 and found a logarithmic temperature dependence of the heat capacity above Tc.
TL;DR: In this article, the tetraamminepalladium(II) ion with hydrochloric acid was shown to have an ambiguity in interpretation for consecutive reactions of the type A→B→C.
TL;DR: The algorithm presented here should be thought of as replacing the basic algorithms in [3] and [4], and the important theoretical work developed in both should be used to calculate the knapsack function for large arguments.
01 Jan 1969
TL;DR: The downward transport of radioactive debris from the stratosphere in association with tropopause-level cyclogenesis offers a possible physical explanation for seasonal and shorter-period surface fallout increases as discussed by the authors.
Abstract: The downward transport of radioactive debris from the stratosphere in association with tropopause-level cyclogenesis offers a possible physical explanation for seasonal and shorter-period surface fallout increases. To examine these possibilities, a simple circulation index which is related to the degree of cyclonic activity in the upper troposphere is compared to a time series of area-averaged fallout intensity. The comparison reveals that the spring fallout peak cannot be explained adequately by an increase in cyclonic activity at this time of year. Shorter period increases, however, are strongly related to occurrences of intense cyclogenesis in the upper troposphere.
TL;DR: This study examined the effects on the perceptual processes when the contours of a map are layer tinted with various colors and found layer tinting had a detrimental effect and significantly increased times to determine grid coordinates on the same map.
Abstract: The purpose of this study was to examine the effects on the perceptual processes when the contours of a map are layer tinted with various colors. Data from military officers serving as Ss indicated layer tinting significantly reduced the times to determine altitudes of specific locations on a map. However, layer tinting had a detrimental effect and significantly increased times to determine grid coordinates on the same map.
TL;DR: In this article, the energy distributions of electrons of about 54, 75 and 97 Mev have been measured before and after passing through aluminum absorbers of thicknesses ranging from 0.730 to 5.574 gm/cm2.
Abstract: The energy distributions of electrons of about 54, 75 and 97 Mev have been measured before and after passing through aluminum absorbers of thicknesses ranging from 0.730 to 5.574 gm/cm2. The electrons were accelerated by the LINAC of the Naval Postgraduate School. The most probable energy losses agree with the theory ofBlunck andWestphal for all thicknesses; the half widths of the distributions agree with theory except for large thicknesses, where they exceed the theoretical values. These results are in contrast to those ofBreuer, which indicate systematically large half widths and most probable energy losses which are greater than theory for thicknesses greater than about 2 gm/cm2. Since our data agree with those ofBreuer, the difference occurs in the treatment of the theory.
TL;DR: The work described here to apply multivariate analysis techniques to heart rate, skin temperature, skin resistance, three aspects of blood pressure (systolic and diastolic blood pressures and pulse pressure), and detection performance as well as simple correlation sing these parameters.
Abstract: The research of Eason, Beardshall, and Jaffee ( 1965 ) , Andreassi, Rapisardi, and Whalen (1967), and others has suggested that significant simple correlation between certain physiological parameters and monitoring performance does exist and should be studied. The work described here so~lght to apply multivariate analysis techniques to heart rate, skin temperature, skin resistance, three aspects of blood pressure (systolic and diastolic blood pressures and pulse pressure), and detection performance as well as simple correlation sing these parameters. Six Ss observed the movement of a voltmeter needle during fo~lr 12-min. periods of a 48-min. task, similar to that described by Poock and Wiener ( 1966). Parameter measures were continuously recorded. Analysis of variance colnputations showed heart rate ( F = 3.58, df = 3/15, p < .05), systolic blood pressure (I; = 2.56, c-lf = 3/15, p < . lo ) , and skin temperature (F = 2.50, df = 3/15, p < . l o ) were the only parameters differing significantly during the four periods. Simple linear correlational analyses indicated the following correlations with monitoring performance: systolic blood pressure .38 ( P < .OS) , skin temperature .38 ( p < .08) , and diastolic blood pressure .33 ( P < . 1 3 ) . Multiple correlational techniques revealed systolic blood pressure and skin temperature to have the highest pairwise relationship with detection performance, R = .50 ( p < .06), while the addition of pulse pressure as a third variable increased R to .54 ( p < .08). Other variables did not contribute significantly to R. As a side note, a slight improvement in detection performance did occur in the fourth period, and an ad hoc analysis on the first three periods of declining monitoring performance, showed R = .67 ( p < .04) for systolic blood pressure, skin resistance, and skin temperature with monitoring performance. During the first three periods, performance had declined 15 %. Finally, when comparing parameter means for detected versus missed signals, skin (emperanlres averaged approximately 2OF higher ( t = 2.78, df = 190, p < .01) when signals were detected than when missed. There were only four commissive errors in all so these were not analyzed.
TL;DR: The article of record as published may be found at http://dx.doi.org/10.1175/1520-0450(1969)008 2.0.CO;2
Abstract: The article of record as published may be found at http://dx.doi.org/10.1175/1520-0450(1969)008 2.0.CO;2
TL;DR: In this paper, the results of a comprehensive study of the comparative performance characteristics of geometrically similar vented and unvented bistable amplifiers, together with their actual dimensions, are presented.
Abstract: : The results of a comprehensive study of the comparative performance characteristics of geometrically similar vented and unvented bistable amplifiers, together with their actual dimensions, are presented. The Reynolds number in the tests ramged from 9,750 to 60,000, Mach number from 0.07 to 0.42, and the power jet velocity from 75 to 460 ft/sec. Each amplifier as conceived and designed was capable of giving a maximum of geometric flexibility which enabled a systematic evaluation of the shape and location of the splitter plate and Coanda walls. (Author)
TL;DR: In this article, an original method of predicting the resistance-force diagram of a particular contact configuration is presented, which utilizes the true stress-strain diagram in tension or compression to predict the slope of the linear force diagram, which is then determined by measuring contact resistance and the applied contact force at that resistance.
Abstract: An original method of predicting the resistance-force diagram of a particular contact configuration is presented. Mathematical theory utilizes the true stress-strain diagram in tension or compression to predict the slope of the linear-force diagram. The position of this slope is then determined by measuring contact resistance and the applied contact force at that resistance. The metals to be studied are fine silver and copper.
TL;DR: In this paper, a chart and formulas give values of ΔT 1, max, ΔT 2, and N Fo as functions of N Bi for the case of sudden change in temperature of fluid flowing in a thin wall insulated pipe.
TL;DR: In this article, the authors examined the Benard convection problem using a geophyisical model in which the eddy coefficients of viscosity and heat conductivity vary linearly with depth.
Abstract: The Benard convection problem is examined using a geophyisical model in which the eddy coefficients of viscosity and heat conductivity vary linearly with depth. For variations corresponding to measured coefficients, the temperature difference over the fluid layer necessary for thermal instability decreases by up to 40% of that needed when the coefficients remain constant. The first unstable mode is affected very little by the coefficient variation. The position of the lower oceanic boundary of a convective layer is discussed briefly.