bluuebunny/crossref_metadata_2025_split huggingface dataset:
"Each to His Own Inheritance" Geography as an Evaluative Tool in the Genesis Apocryphon
Authors: Machiela Daniel 
Published: March 2008

AbstractThe Genesis Apocryphon has often been compared with the Book of Jubilees; especially the parallel accounts of Noah's oversight of the earth's post-flood distribution between his sons and grandsons (1QapGenar 16–17//Jub. 8:8–9:15). A close examination of the Genesis Apocryphon demonstrates that, while this comparison is valid, the two works are more different than scholars have typically assumed. Not only is the treatment of Noah's special role and the earth's proper division more widespread and prominent in the Apocryphon than in Jubilees, but the most directly corresponding passage exhibits a different arrangement. This may suggest a common cartographic source, and attests to a more robust interest in such geographic matters on the part of the Apocryphon. While both authors clearly drew on similar traditions, it is suggested that the author of the Genesis Apocryphon was more occupied with the right of Israel to the Promised Land than the author of Jubilees.
Real-Time Analog-Digital Computation
Authors: Connelly Mark E. 
Published: March 2008

The relative advantages of analog and digital tech niques in simulating complex, nonlinear systems in real-time are discussed. A hybrid configuration is suggested consisting of a basic digital computer and peripheral, high-speed analog elements used on a time-shared basis under the control of the digital program. Programs for function generation and for the solution of the aircraft roll equation are presented to illustrate the operation of the hybrid computer and the significant increase in the effective computing speed of the digital computer that results from the incorporation of peripheral analog elements. Further gains can be made by tailoring the order code and logic of the digital computer to the specific prob lem class of interest. The hypothesis is presented that a hybrid computer is technically feasible today that would be competitive with analog techniques on the basis of both cost and the ability to simulate natural aircraft frequencies in real-time. Moreover, such a computer would offer substantial advantages with respect to accuracy, dynamic range, flexibility, size, power consumption, and reliability.
A Comparison of Higher-Order Difference Methods in the Solution of Beam-Vibration Problems
Authors: Greenwood Donald T. 
Published: March 2008

Several higher-order difference methods are investi gated and compared for the problem of finding the natural frequencies of the lateral vibration of a beam. All of the methods considered are applicable to either digital or analog computers, although particu lar reference is made to the analog computer. The methods considered in most detail use the same basic central difference approximation, the variations occurring in the method of representing boundary conditions. Three higher-order approaches to the problem of boundary conditions are pre sented. They are 1) the use of one-sided differences of fourth order, 2) the use of symmetry assumptions, and 3) the passive-circuit approach. Each method is shown to have its advantages, the final choice de pending upon the particular requirements of the problem. Results are presented in the form of curves of per centage mode-frequency error vs number of cells for the various approximation methods.
The Heat and Mass Flow Analyzer
Authors: Paschkis V. 
Published: March 2008

After having introduced in a simplified way the RC circuit-heat conduction analogy in one- and two- dimensional problems, the influence of variable properties is added to the electrical setup. The processes involving freezing and melting of pure metals and alloys are studied as an important application of these simulators. Problems with repetitive processes are particularly suited to be solved by computers. Networks can be built for simulating heat exchange. These simulators can be made more flexible by introducing active elements like voltage-dependent voltage- and current-sources. One application of these devices is the simulation of a thermal regen erator. A DC-electrolytic tank has been developed for the study of three-dimensional problems.
Simulation of Human Problem-Solving Method
Authors: Johnson D.L. , Holden A.D.C. 
Published: March 2008

One of the most intriguing and potentially important applications of the digital computer is in the simula tion of human thought processes. The objects of thought when suitably coded can be transformed, classified and stored within the computer at will. The predominant charactertistic of human thought processes is their generality. To make any progress in the simulation of such processes, it is first necessary to isolate a small region and examine it in isolation. As progress is made in one region, it can be ex panded and generalized to include a wider field, and it is likely that many of the methods used in a re stricted field will be susceptible to modification for use in a larger area. It is desirable to work initially in a region in which the relationships between the ob jects of thought are clearly defined. This report deals with the problem of finding se quences of transformations which constitute proofs of trigonometric identities. The method described need not be confined to this particular problem, but could easily be used in other fields if the allowable transformations are known. The behaviour of a ma chine which has been programmed to carry out this process is described in detail and its responses, when several identities were presented to it for proof, are given. No attempt is made to use the method of finding proofs by exhaustive search, even though in this case such a search is quite feasible, since the number of "basic" trigonometric transformations which can be applied to a given function is relatively small. It is considered here that such repetitive "trial and error" methods are less interesting than the methods which we shall discuss. It is desirable to decide on the best transformation for a particular problem by compar ing the characteristics of the problem with the prop erties of each transformation in such a way that the machine's performance will improve with experi ence. Exhaustive search methods become useless when the number of possible decisions at each step becomes large.
Limitations due to Noise, Stability and Component Tolerance on the Solution of Partial Differential Equations by Differential Analysers
Authors: Fisher Michael E. 
Published: March 2008

The solution of partial differential equations by a differential analyser is considered with regard to the effects of noise, computational instability and the deviation of components from their ideal values. It is shown that the 'serial' method of solving parabolic, hyperbolic and elliptic equations leads to serious in stability which increases as the finite difference interval is reduced. The truncation error (due to the difference approximations) decreases as the interval is made smaller and consequently an 'optimal' ac curacy is reached when the unstable noise errors match the truncation errors. Evaluation shows that the attainable accuracy is severely limited, especially for hyperbolic and elliptic equations. The 'parallel' method is stable when applied to parabolic and hyperbolic (but not elliptic) equations and the attainable accuracy is then limited by the accumulation of component tolerances. Quantitative investigation shows how reasonably high accuracy can be achieved with a minimum of precise adjustments.
Substitution Methods for the Verification of Analog Solutions
Authors: Meissinger Hans F. 
Published: March 2008

Substitution of analog computer solutions into the original differential equations followed by an iter ative or a variational procedure can be employed as a practical verification technique and as a method for improving solution accuracy. The method has the advantage of utilizing information contained in the analog solution and, therefore, yields results more rapidly than the conventional procedure of deriving an independent numerical check solution. It is also valuable as an aid in locating the source of computer errors. Theoretical and practical aspects of the substitu tion check method are discussed and illustrative examples are presented in this article.
Computer Programming
Authors: Hammond Joseph L. 
Published: March 2008

State variable techniques are reviewed and applied to analog computer programming. The concise rep resentation for ordinary differential equations made possible by this technique is used to formulate a gen eral program for all such equations. It is shown that an analog computer program based on state variables will not have redundant integrators. The fact that the use of state variables facilitates the choice of variables internal to an analog com puter program is illustrated by two techniques, namely, (1) a technique for avoiding derivatives of the forcing function in programming a large class of ordinary differential equations, and (2) a technique for simulating certain systems in such a way that the effect of each characteristic root is placed in evi dence.
A New Numerical Method for Simulation
Authors: Fowler Maury E. 
Published: March 2008

This paper illustrates a method of digitally simulating the motion and control of vehicles. This method of simulation has been used for the simulation of a large variety of systems, including a six-degree-of- freedom simulation of Gemini reentry with guidance and control, a six-degree-of-freedom aircraft simula tion, missile control simulations including bending modes, trajectory problems, and many others. The major advantage of the method, in addition to the speed of computation, is that a detailed an alysis of the system is carried out during the develop ment of the simulation. Although, for small problems, simulations using this method can be derived by hand, large simula tions generally require a computer program to com pute root locus points and z-transforms.
Transistors in Current-Analog Computing
Authors: Kerfoot Branch P. 
Published: March 2008

A system of electronic analog computing is described in which current is used as the variable. The paper indicates that the circuit properties of transistors make them especially suitable for use in operational amplifiers for this computing technique. Experimental direct-coupled amplifiers are shown which have been built and evaluated using low- power, low-frequency transistors. The amplifiers have been employed under laboratory conditions to per form the operations of summation, scale-change, integration, and differentiation. The factors which determine computing accuracy are analyzed, and a new technique of error predic tion (based on square-wave output) is discussed. The paper concludes that the current-analog meth od promises to use transistors effectively.
Tracking system simulation with variable delay
Authors: Robb R.E. 
Published: March 2008

This paper describes the analog simulation developed to evaluate a digital control program. The digital pro gram is a doppler prediction program which updates a ground transmitter so that the input frequency to an airborne transponder is held constant. It describes the simulation of the transmitter, re ceiver, transponder and the air-to-ground links be tween the transponder and the transmitter and re ceiver. One of the unique features of the simulation is the dynamic time delay between the transponder and its ground stations. The simulation is an example of direct modeling of the real-time transfer functions.
EASL ... a digital computer language for "hands-on" simulation
Authors: Schlesinger S.I. , Sashkin L. 
Published: March 2008

EASL was developed to provide a simple language which would be easy to use by the occasional computer user, whether his background was analog or digital computing, and yet be powerful enough for use in programming com plicated computer applications. The language borrows liberally from the concepts of both analog and digital com puting in order to provide a framework in which a pro grammer from either field would feel at home. At the same time, the user has available the advantages of both disciplines so that he can operate as if he has a very sophis ticated hybrid system in which analog and digital com ponents can be readily intermixed. In order to facilitate the use of EASL for engineering simulation studies, the capability of loading data and pro ducing graphical and tabular reports is provided in a man ner which is easily implemented by the user. Convenient algebraic representation is provided by FORTRAN state ments, and a simply-applied integration operation permits solution of systems of differential equations. The inherent simplicity of data input and output, where all references are made by the variable's name (which is provided by the user), lends itself to the adaptation of consoles to en able the user to monitor and control his computation. These consoles provide a "hands-on" capability for rapid control of computation based upon visual inspection of graphical output.
New Approaches To the Design of Active Filters
Authors: Hansen Peter D. 
Published: March 2008

Operational amplifiers can greatly simplify the design of high performance signal filters because they elimi nate the need for inductors and for impedance matching. Furthermore, use of active filters can result in reduc tion of weight, size, and cost. Filters designed to satisfy sophisticated mathematical criteria can be realized without resort to "equalization" or trimming. In this issue we discuss the design of operational amplifier and analog computer circuits suitable for use as low pass filters. We also discuss the commonly used mathematically designed filters, i.e. Butterworth, Chebyshev, and Bessel. In addition, we present two new types of theoretical filters, the Paynter and the Aver aging filters. Design data necessary for realizing these theoretical filters with amplifier circuits is provided. In the next issue we shall discuss the design of band pass, band reject, high pass and all pass active filter circuits.
Hybrid techniques for generation of arbitrary functions
Authors: Rubin Arthur I. 
Published: March 2008

A discussion of the implementation of a true hybrid func tion generator module is presented. Included is a detailed description of how two of these modules, when used in conjunction with a hybrid computer, are used simultane ously to generate a continuous function of two variables, and how four modules are used to generate a continuous function of three variables. From a variety of possible con figurations, an optimum choice for a general-purpose HFG module is made, taking into account digital coefficient storage requirements and analog multiplier requirements. A detailed error analysis compares the errors produced in generating an arbitrary function using the HFG module with the errors produced by the classical hybrid (or purely digital) method of generating an arbitrary function by table look-up and interpolation for discrete values of the argu ment. The conclusion is reached that the hybrid method can be an order of magnitude more accurate than the classical discrete method for generating arbitrary functions and has further advantages in that the hybrid method does not require a 100°lo duty cycle in the digital processor for accurate function generation.
Circle test evaluation of a method of compensating hybrid computing error by predicted integral
Authors: Deiters Robert M. , Nomura Tamiya 
Published: March 2008

In a real-time hybrid computing system using an analog and a digital computer joined by ADC and DAC linkage, the continuous analog signals are inevitably sampled and delayed by the ADC-digital computer-DAC execution time. We propose a method of compensating for this error in which the digital computer predicts the integral of the ideal continuous output over each delayed sample period. This predicted integral, then, determines the DAC output having the same integral value over the delayed sample period. Here we have considered only the zero- order hold DAC, but the method is easily extended to other types of hold circuits. The digital prediction algo rithm is based on backward difference extrapolation of the values derived from present and past DAC samples. We tested the effectiveness of this method in a hybrid circle test. Z-transform numerical calculations indicate that sampling rates as low as 20 samples per cycle of oscilla tion and digital execution time as long as 9/10 of a sample period are permissible when backward differences up to the fifth order are used. An actual hybrid circle test with only 10-bit rounded off accuracy in the converters con firmed the effectiveness of the method, even in the pres ence of errors in the analog error range. Using numerical inversion of the z-transform model we computed a number of charts to guide hybriders in select ing a suitable order of the compensation algorithm and sampling frequency. The graphs show the divergence (due to uncompensated time delay) and frequency error (due to loop gain error) as functions of sampling frequency. The parameters for these graphs are digital execution time and the order of the backward difference algorithm.
Analog simulation of satellite times-in-view
Authors: Bryan Roger N. 
Published: March 2008

During the planning stages of any communication or com mand/control system utilizing satellites, it is necessary to examine the ground-terminal/satellite geometry for many proposed configurations in order to find the one most suitable. By "most suitable," I mean the configuration exhibiting the greatest ground-terminal-to-satellite acces sibility as demonstrated by a maximum time-in-view. The procedures I describe in this paper provide a means for rapidly generating ground terminal/satellite visibility records via an analog computer simulation of the Earth's surface/satellite orbit geometry. The analog simulation has several significant advantages relative to similar digital computer approaches-(1) it is significantly faster (easily 15,000 times real-time) and less expensive to operate; (2) the output, ink-on-paper strip-chart recordings, is directly interpretable without further data reduction; (3) system parameter changes are readily introduced while a simula tion is in progress; (4) the Systems Analyst can maintain a decidedly greater rapport with his configuration analysis. The disadvantages are: (1) diminished accuracy, and (2) exclusion of Earth/orbit non-linearities and anomalies—in a real-time tracking or scheduling simulation, these dis advantages are serious; in a systems analysis tool such as this time-in-view simulation, they are not of great con sequence. I have devoted the first five sections of this paper to a description of the development of the vector-matrix model underlying the simulation. The sixth section describes the mechanization of the model using an electronic analog computer. The equations from which the computer potentiometer settings are derived are quite tedious to manipulate man ually—even aided by a desk calculator. In an appendix, I describe the simple digital computer (in my case, a RE- COMP II) program used to obtain the desired potentiom eter settings. It strikes me that, while lack of simultaneity in the usage of the analog and digital machines precludes the use of the word hybrid, we may validly coin the expression "syner getic computing" to describe this simulation.
Fields, and methods of their simulation and exploration
Authors: Soudack Avrum , Uhlig C.A. Edward 
Published: March 2008

Since the treatment of the general field concept seems to be missing in the literature, and since methods of field ex ploration and of simulation are scattered in a great number of domestic as well as foreign papers, this paper presents, first, a brief survey on fields and on methods of their analy sis and simulation, and then reports on the state of the art in the area of simulation of electrostatic fields by means of a conductive-sheet analog or electrolytic tank. Although the paper has been written primarily with the needs of electric power engineering in mind, the treatment of the subject has been held as interdiscipli nary as possible. The paper will thus be useful also to those working in aerodynamics, elastic stress analysis, heat transfer, astronomy, acoustics, atomic physics, and ma terial sciences. Furthermore, for the electrical engineer, it may be helpful to know that electrical problems sometimes may be solved more easily or more conveniently by the use of nonelectrical methods. In the specialized section on the application of the electrolytic tank and the conductive-sheet analog to the solution of electrostatic field problems, little-known as well as new techniques are discussed, such as (1) plotting of infinite fields on a double analog, (2) determining of force lines or surfaces by means of the dual analog, (3) simulation of areas of different dielectric constants and of continuously variable dielectric constants by means of jellified dielectrics, (4) plotting of areas of low current density by the use of consecutive field mapping, (5) the possibility of plotting fields with rotational symmetry on isotropically conducting sheets and graphically transpos ing the map so obtained, and (6) solution of distributed source problems. A comparison of advantages, disadvantages, and limita tions of the electrolytic tank method and the conductive sheet analog is also presented. Finally, an appeal is made for teaching and use of field analog methods for future developments.
Digital simulation of general control systems
Authors: Trauboth Heinz H. , Burgin George H. 
Published: March 2008

A numerical method and a program for the computation of the time responses of any complex multiloop control system are described in principle. The control systems are represented by block diagrams which are formed by the linear and nonlinear blocks well known in control engi neering. The properties of these blocks are given by simple relations between input and output signals in the time domain at discrete and equal intervals. Any number of input signals may be fed into the system at any point of the system. Initial conditions may be treated in a simple way like input signals. The input signals and weighting functions may be arbitrary time functions or impulse func tions given in analytical or numerical form. There is no need for special treatment of algebraic loops and of se quencing. The mathematical method is especially suited for programming an electronic digital computer. The simulation program makes the work on the digital computer very easy. It computes the signals as functions of time at all points of the system. Several examples of linear systems were simulated on a Siemens-2002 with favorable results. Among others, a medium-size control system was simulated on this relatively slow computer in 3.2 minutes (compared to a real time of 26 minutes) and with more accuracy than on a medium-size analog com puter.