Showing papers by "RAND Corporation published in 1969"

Multiproject Scheduling with Limited Resources: A Zero-One Programming Approach

Abstract: A zero-one 0-1 linear programming formulation of multiproject and job-shop scheduling problems is presented that is more general and computationally tractable than other known formulations. It can accommodate a wide range of real-world situations including multiple resource constraints, due dates, job splitting, resource, substitutability, and concurrency and nonconcurrency of job performance requirements. Three possible objective functions are discussed; minimizing total throughput time for all projects: minimizing the time by which all projects are completed i.e., minimizing makespan; and minimizing total lateness or lateness penalty for all projects.

Simultaneously recorded trains of action potentials: analysis and functional interpretation.

Abstract: A new kind of statistical display, the joint peri-stimulus-time scatter diagram, facilitates the analysis and interpretation of two or more simultaneously recorded trains of action potentials. The display is a generalization of the cross correlation and the peri-stimulus-time histogram, and it reflects specific underlying neuronal interactions. The technique yields quantitative measures of interaction in terms of effectiveness of synaptic connections.

Numerical Simulation of the Atmospheric Circulation and Climate of Mars

Abstract: Two level model for planetary atmospheres adapted to simulate atmospheric circulation and climate of Mars

EXDAMS: extendable debugging and monitoring system

Abstract: With the advent of the higher-level algebraic languages, the computer industry expected to be relieved of the detailed programming required at the assembly-language level. This expectation has largely been realized. Many systems are now being built in higher-level languages (most notably MULTICS).

Risk and Corporate Rates of Return

Abstract: : Although economists have great interest in the correlation between risk and profits, few studies have attempted to quantify the relationship. Consequently, this paper considers the concept of risk differentials in corporate profit and proposes a model for measuring them. Using this model, the risk-rate of return relationship was estimated for a sample of firms in various industry groups. For each industry group, average risk-adjusted rates of return were also obtained.

Optical Properties of Cerium-Activated Garnet Crystals*

Abstract: The optical properties of cerium-activated garnet crystals have been investigated. In the garnet crystals showing luminescence, a bright-yellow fluorescence has been observed. The fluorescence exhibits structure at low temperatures, and the wavelength maxima of the fluorescence-spectrum profiles are found to be host-dependent. Energy transfer has been observed from the cerium ion to the neodymium ion.

The Influence of Random Filament Packing on the Transverse Stiffness of Unidirectional Composites

Abstract: Existing micromechanics analyses for the prediction of composite material properties, which are based upon the assumption of various idealized regular filament packings, indicate the significant in...

The Recursive Unsolvability of the Decision Problem for the Class of Definite Formulas

Abstract: A class of formulas of the first-order predicate calculus, the definite formulas has recently been proposed as the formal representation of the “reasonable” questions to put to a computer in the context of an actual data retrieval system, the Relational Data File of Levien and Maron. It is shown here that the decision problem for the class of definite formulas is recursively unsolvable. Hence there is no algorithm to decide whether a given formula is definite.

Mariner 6 and 7 television pictures: preliminary analysis.

Abstract: Before the space era, Mars was thought to be like the earth; after Mariner 4, Mars seemed to be like the moon; Mariners 6 and 7 have shown Mars to have its own distinctive features, unknown elsewhere within the solar system.

Price strategy oligopoly with product variation

Abstract: : This paper mathematically formulates an example of firms in monopolistic competition and investigate noncooperative behavior as the number of firms increases and as the level of product variation is decreased.

Dual clocking arrangement for a digital computer

Abstract: In most general purpose digital computers, there are some instructions that require a relatively long execution time. Some examples of these extended sequence instructions would be multiply, divide, square root, etc. When starting the execution of this type of instruction, it is necessary to interrupt the normal timing of the computer and to implement an ''''arithmetic hold'''' condition which, in effect, keeps the computer from fetching a new instruction while the extended sequence instruction is being executed. In the present invention, two 4phase different-speed clocks are utilized. The pulse repetition rate of the first low-speed clock may be substantially less than that of the second high-speed clock. Suitable control circuits are provided for sensing when an extended sequence-type instruction is involved and for switching in the high-speed clock such that the extended sequence instruction is executed at a higher rate than is a normal instruction.

Optical radiant energy encoding and correlating apparatus

Abstract: Object locating apparatus including receiver optics for focussing optical radiant energy emitted from an object within its field of view onto a rotatable drum having a plurality of pseudo-random coded sections disposed along a continuous loop track, the code pattern in alternate sections being identical while those in adjacent sections are skewed and inverted relative to one another. Rotation of the drum uniquely encodes the radiant energy in accordance with its position thereon and a photodetector converts the encoded energy to an equivalent electrical signal preparatory to correlation with a reference code for a period equal to the time required for two of the drum sections to pass through the field.

A review of atomic and molecular excitation mechanisms in nonequilibrium gases up to 20 000°K

Abstract: This review summarizes present knowledge of the atomic and molecular mechanisms that produce or remove rotationally, vibrationally, and electronically excited species in heated or excited gases. A logical classification scheme for these mechanisms is introduced, and the extent of present information on each class is indicated. The validity and utility of several general rules and regularities are also examined. An appendix includes a table of rate coefficients for vibrational and electronic excitation and deexcitation reactions, taken directly from or derived from data in the literature. This table provides comprehensive coverage of some classes of reactions and representative coverage of the others.

Invariant Imbedding and Sequential Interpolating Filters for Nonlinear Processes

Abstract: : The study shows how a sequential solution can be obtained for a fairly general nonlinear interpolation problem using a least-squares criterion for estimation, along with invariant imbedding techniques. The equations of the sequential interpolating filter are obtained by first showing the interpolation problem to be equivalent to a two-point boundary-value problem. The two-point boundary-value problem is then converted to an initial-value problem by means of invariant imbedding, and the initial-value problem leads directly to a sequential filter. To avoid unnecessary matrix manipulations, the formulation and solution are given for the scalar case only. Generalization to the vector case is straightforward. (Author)

Aperture averaging factor of a fluctuating light signal

Abstract: : The aperture averaging factor, which gives the effect of a finite diameter receiving aperture in reducing the variance of a fluctuating light signal is studied. (Author)

Two-way communication system employing two-clock frequency pseudo-noise signal modulation

Abstract: A digital two-way communication system utilizing RF transmissions that are phase-shift-keyed (PSK) by binary pseudo-noise (PN) code generators operating at different clock rates. Transmissions in the first and second directions are modulated by composite PN code generators operating at different first and second clock frequencies f1 and f2, respectively, where f1 = NF2, with N being a positive integer having no factors in common with the lengths of the component PN coder from which the composite is formed. The binary digital data signals that are to be transmitted in either direction modulate a binary PN code which is a composite code generated from a plurality of component PN codes. Each of these data-modulated composite PN codes, which are generated at clock frequencies f1 and f2, respectively, modulates, in turn, an RF carrier signal.

Turbulent shear flows of variable density.

Abstract: : A study was made of the mean flow field of free turbulent layers of variable density showing that if the velocity distribution in a particular constant-density flow is known, it is possible to obtain the corresponding variable-density velocity field without the introduction of a compressible turbulent viscosity. This is accomplished by a Dorodnitsyn-Howarth type of transformation applied to the time-dependent equations of motion rather than to the mean equations of motion, as has been done previously. When the transformed equations are averaged, using Reynolds' method, the incompressible turbulent equations for the mean flow are obtained. These equations can then be handled by conventional methods. Predictions obtained by this procedure agree well with experimental results.

Plated-wire technology: A critical review

Abstract: Electrodeposited cylindrical magnetic film memory technology is reviewed. Extensive references are made to previous work. New data is given in areas not previously reported. Special emphasis is given to the following items: 1) Applications: Plated-wire applications cover the spectrum from 100 to 1000 ns cycle time NDRO memories of 105to 107bits capacity in commercial and military markets. 2) Processing: Substrate preparation and electrochemical processing, as well as alternative magnetic plating solutions, and the control of pH, temperature, flow rate, Ni-Fe ratio, and other variables necessary for high yield plating are reviewed. 3) Aging: The conditions that stabilize the film and the test methods that predict a 10- to 100-year life are reviewed. 4) Testing: A practical approach to continuous production line testing is reviewed. 5) Bit Packing Density: Calculations on magnetization distribution along the wire are compared to experience. Although memory plane geometry is important, the wire characteristics dominate the achievable bit density. Wire diameter, film thickness H k , and other factors are included in graphs useful for design purposes. 6) Memory Plane Construction: The relative advantages of several different forms are compared. The need for magnetic keepers and their advantages are reviewed. 7) Interactions: New data is presented on some of the effects of variations in word strap alignment and spacing as well as the sensitivity to variation in plated-wire spacing and bending.

Reflection and transmission functions for finite isotropically scattering atmospheres with specular reflectors

Abstract: A finitely thick isotropically scattering atmosphere is bounded below by a specular reflector. A Cauchy system for the scattering and transmission functions is obtained. Results of numerical experiments are presented.

Adaptive Routing Techniques for Distributed Communications Systems

Abstract: The concept of a netted or distributed communications system is significant because it offers a major advantage over conventional communications systems, i.e., a better chance of providing surviving lines of communication after an attack on the system. During and after an attack, however, an effective adaptive routing technique is necessary to adjust the routing tables of the message-switching control system to the changing situation. Previously investigated adaptive routing techniques are shown to be insufficient for the task, and a number of promising alternatives are formulated and investigated such as some stochastic techniques, which use information on messages passing through the network to adjust the tables, and some deterministic techniques, which use dynamic programming or graph-theoretic algorithms to recalculate changes in the tables from observed changes in the network. Each alternative has operational advantages, which make it good for certain types of communications systems, and certain disadvantages if applied to others. Regions of applicability and inapplicability, with respect to the above system parameters, are given for the various techniques. Recommended techniques are specified for two currently proposed applications of distributed communications systems. A number of research areas are pointed out in which further efforts in the analysis and simulation of adaptive routing techniques will have useful payoffs in the design of future distributed communications systems.

Automatic infusion brew maker

Abstract: An automatic infusion brew maker comprising a pair of reservoirs and a pair of heat pumps connected thereto. The two heat pumps are driven by a common electrical heating means. Water from the first reservoir is pumped into a removable steeping basket, passes through a filter and exits through an outlet below the steeping basket. Water from the second reservoir is heated and pumped directly to the steeping basket outlet, thus bypassing the material to be steeped.

Finite-Element Applications in Fluid Dynamics

Abstract: In this note, the application of the finite-element method to a class of problems in fluid dynamics is considered Such applications involve several pecularities not encountered in the usual struct

A Transform for Logic Networks

Abstract: The transform presented in this paper applies to functions which describe logic network behavior. Given a function G defined over a finite domain, it is shown that G(u) = Et F(t)ut for each element u in the domain, where finite-field arithmetic is assumed. Here, function F is the transform of G, and it is shown that F(t) = Eu G(u)(-u)-t for each integer t in a finite set. Both form and development of this transform pair resembles the Fourier transform in harmonic analysis.

Direction of Easy Magnetization in Gadolinium

Abstract: The direction of easy magnetization in Gd is studied as a function of temperature and pressure. The pertinent experimental results have already been given by Robinson, Milstein, and Jayaraman. A Gd sample was used as the core of a small transformer; a constant input voltage was supplied to this transformer. The secondary voltage was monitored as a function of temperature at several constant pressures. The secondary voltage of the transformer, being proportional to the permeability of the sample, is a sensitive indicator of changes in magnetic structure in the Gd sample. Typically, the secondary voltages behave as follows as the temperature of the transformer is lowered: A sharp rise in the secondary voltage occurs at the Curie temperature, followed by another sharp rise at a temperature well below the Curie point. The magnitude of the secondary voltage at this latter transition is from two to three orders of magnitude greater than at the transition from the paramagnetic to the ferromagnetic state. This transition is interpreted as a magnetic transition in which the direction of easy magnetization in Gd deviates from the $c$ axis. The angle of deviation is discussed in terms of the (small) anisotropy constants resulting from the weak crystalline field in Gd. In terms of the output voltage, one is able to obtain the relative deviations of the direction of easy magnetization from the $c$ axis. The temperatures, as a function of pressure, at which the maximum deviations occur can also be obtained. As the temperature is lowered further, the direction of easy magnetization starts to approach the $c$ axis again. Comparisons are made with other measurements of this angle of deviation.