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HT-1 is the designation for an experimental high temperature resistant polymeric material under development by the Du Pont Company. It is being developed to fulfill the need for a product which combines durability under high temperature conditions with those mechanical and electrical properties required for acceptable performance in a wide range of industrial end uses. HT-1 can be produced as filament yarn, staple fibers, paper, and in thick or boardlike structures. On the basis of experimental product evaluations and encouraging market prospects, a pilot plant for production of the material is being constructed. This unit will have a nominal capacity of 1MM pounds per year of product and is expected to be on stream about the end of 1962.

This paper is concerned with infinite state probabilistic transition tables, representing the dynamical behavior of a probabilistic automaton and nonhomogeneous infinite-state Markov chains. Many known theorems are generalized from the finite state case to the infinite state case. A possible application to the problem of computing, approximately, products of infinite state stochastic matrices is outlined.

The paper presents some breakdown phenomena which take place in a uniform field gap (Rogowski gap) with an auxiliary electrode. This constitutes a part on an investigation to find a new method for determining the voltage distribution in the gap immediately prior to breakdown.

Glass for deep ocean structres can experience local tensile stresses on the surfaces of internal bubbles even though the applied loads are compressive. To insure the safety and reliability of these structures accurate predictions of the probability of a failure originating at an internal flaw are made based on an assumed Weibull distribution of strengths. This analysis includes the effects of size and dissimilarities between the strength distributions of test specimens and the actual structure.

The paper presents a graphical-numerical method for determining the transient stability limits of a two-machine system under the usual assumptions of constant input, no damping and constant voltage behind transient reactance. The method presented is based on the phase-plane criterion,1, 2 in contrast to the usual step-by-step and equal-area methods. For the transient stability limit of a two-machine system, under the assumptions stated, the sum of the kinetic energy and the potential energy, at the instant of fault clearing, should just be equal to the maximum value of the potential energy which the machines can accommodate with the fault cleared. The assumption of constant voltage behind transient reactance is then discarded in favour of the more accurate assumption of constant field flux linkages. Finally, the method is extended to include the effect of field decrement and damping. A number of examples corresponding to each case are worked out, and the results obtained by the proposed method are compared with those obtained by the usual methods.

A fully integrated analog amplifier which can be used in a variety of applications either as a single element or as a cell in a LSI circuit has been developed for such applications as temperature measurements associated with thermocouples, biomedicine, low-level measurements and A/D converters.

This paper describes a new microwave reflector which appears to have application to scanning problems and problems in which multiple beams from a single reflector are necessary. The vide angle type of reflector is far superior to existing reflectors while the medium angle type shows sufficient superiority to warrant its consideration.

The general theoretical model predicts the amount of threshold voltage change with time for both writing and storage modes of operation. Experimental data fit these theoretical expressions containing no adjustable parameter.

The purpose of this paper is to give an alternative proof to the decidability of the emptiness problem for tree automata, as shown in Rabin4. The proof reduces the emptiness problem for automata on infinite trees to that for automata on finite trees, by showing that any automata definable set of infinite trees must contain a finitely-generable tree.

This paper describes the evolution of modern secant methods and compares their performance.

Requirements of U. S. Department of Defense and other agencies are that system designers control the spectral characteristics of all new transmitters. The purpose of this paper is to consider the noise outputs of all commonly used microwave tubes and from there proceed to survey the methods of removal and elimination of noise by filtering. Practical design tradeoffs comparing desired stopband attenuation levels versus sacrifice in system VSWR, passband insertion loss, power handling, cost, and size are made. Some recent advances in high power microwave filtering are introduced with recommendations of filter chains usable with various tubes and under various conditions.

This paper outlines a method for testing the thermal stability of magnet wire by measuring the viscoelastic behavior of tubed fims obtained from magnet wire manufactured with standard equipment. It was found that there was a correlation between the glass transition temperature obtained from the mechanical tan ? versus temperature curve and the thermal class obtained from the IEEE No. 57 test method. When a magnet wire is heat aged, the mechanical tan ? peak of the film decreases. Regression curves of the mechanical tan ? peak versus aging temperature and aging time were expressed as second-order curves. The activation energies of heat aging were obtained, and compared to the activation energies obtained from the IEEE No. 57 test method.

A shipboard Telemetry Receiver Acoustic Command System (TRACS) was designed to be used for twoway acoustic communication with and relocation of underwater instruments. The design objectives were compact size, low cost, multi-purpose capabilities, and ease of operation and maintenance of the system. The telemetry receiver system utilizes a four-hydrophone array, bandpass filters and amplifiers, precision time-base for synchronization, a writing amplifier, and a helix, wet-paper recorder. The Acoustic Command System (ACS) incorporates an adjustable digital acoustic command generator, a power amplifier, an underwater sound transducer and an adjustable ACS test output circuit useful for alignment of underwater acoustic receivers. Two systems have been used successfully at sea on four cruises.

This paper examines the implications of the hypothesis that a physical process can be modeled by a system of the form (C,A + KC,B) where (C,A) is an observable pair and K and B are parameters to be identified. The hypothesis leads directly to a linear equation relating K,B and a model's state to quantities computable from measured data. The findings of [2-4] are extended by showing that K,B and a model's state can be asymptotically estimated using a dynamic identifier. By relaxing the preceding hypothesis it is shown that these results also apply to more general classes of models.

This paper deals with the problem of enforcing standards of maximum allowable atmospheric contaminants. This enforcement has to be done by deciding whether the actual level of contaminant is in violation or compliance with the standards. Due to inherent uncertainties, a decision is to be made only if the probability of error is below a prescribed level. The measurements of contaminant are modeled as a set of lognormal random variables with unknown mean and variance. A uniformly most powerful unbiased test is developed to test their mean against a given threshold. It is shown that the test can be carried out in a very simple manner with the help of a decision chart. This is done by plotting a point defined by the sufficient statistics of the observations and reading off the decision. The estimate of the actual level of contaminant is also discussed.

This paper presents a technique for obtaining a predictor of the output of a complex linear system. The predicted output is obtained by choosing a suitable combination of some variables which can represent the "most important" states of the system, in such a way that an easily computable bound of the prediction error is minimized. Such a bound moreover results very useful since it gives a measure of the goodness in the choice of the "important" states. The proposed approach seems to be attractive for its simplicity and for the fact that a bound on the prediction error can be estimated.

This paper presents a summary of research directed at the development of algorithms for system identification in large scale systems. Methods based upon sensitivity analysis and hierarchical systems theory are described.

The phase and amplitude weighting of the waveform received at each element of an antenna array can be adaptively controlled in real time to optimize the antenna pattern for a variety of communication links. In this paper we present the results of experiments conducted with an SHF self-phasing array and with an adaptive UHF null-forming array.

This paper evaluates performance of a filter that transforms nonlinear measurements in the coordinate system of the state before using in the filter. The bias and computational performance of this mechanization are compared with the conventional extended Kalman (EK) filter. The bias in the EK filter is a function of the covariance of the estimation error, while in the state-coordinate-system (SCS) it depends on variance of the transformed measurement noise, which is independent of the estimation error and depends only on the nonlinearity. Thus when the initial covariance of the state is large, the SCS filter has less bias than the EK filter. This reduction in the bias is achieved at a cost of additional computations required to implement the transformation. The improved performance of the filter due to the coordinate transformation is then demonstrated with an example of satellite-aided aircraft navigation.

Since multipliers are the slowest and most expensive components in digital filters, schemes for increasing speed and reducing cost are of interest. For a device that does multiplication by successive shift and add operations, different architectures can be used to speed the process and allow for hardware sharing. Several architectures are discussed in this paper. For filters that carry a small digital word length, nonconventional multiply schemes may well be appropriate. Two such schemes, table look up and residue algebra, are discussed herein.

This paper discusses the concept of strong instrumental variables and strong instrumental matrix sequences for the estimation of the transfer-function parameters of discrete-time, time-invariant models of linear systems. It is shown that strong instrumental variable estimators are strongly consistent and a sufficient condition for the estimator to be asymtotically unbiased is given. Moreover, it is shown that with a persistently exciting signal of appropriate order for an input, "virtually" any discrete-time, time-invariant, linear system model of appropriate order can be used to generate strong instrumental variables.

This paper could well be titled, "Systems Engineering for Navy Platform Effectiveness," since the major decision and control issues are focused on optimizing the performance of the platform. Platform effectiveness is largely determined by the electronic systems aboard. In the past, optimizing such electronic systems usually reverted to the effectiveness of a software system contained in a general purpose digital computer. The role of the system engineer usually broke down somewhere between identification of functional requirements and transfer of these into computer instructions by programming personnel. The reasons for past failures and the challenge of new approaches are the theme of this presentation. In summary, what is needed most is unambiguous communication among all persons involved in development of Navy digital electronic systems, with the most probable solution resting in the language of mathematics, science and engineering.

This paper reviews a learning process for the development of a model of a specific physiological control system. It provides an example of a nonlinear system structure, and elucidates processes of aggregating biological variables and of decomposing a system model at different time scales. A quasilinear approximate analysis of the model suggests an adaptive control mechanism which is yet to be explored.

Surveillance systems are often required to simultaneously estimate the trajectory parameters of several targets. This problem is complicated significantly in high target density situations since the individual data sequences required by standard estimation algorithms are difficult to form. This paper discusses certain computational aspects of assigning closely spaced sensor returns to individual tracks. We refer to this as a "multiple choice" estimation problem since the real tracks are generally hidden in a large set F of feasible tracks. Forming the feasible track set F on the basis of a priori knowledge of the problem is the first step on the assignment process. A subset of the potential tracks contained in F is then selected on the basis accomplished by 0-1 integer programming, as we now illustrate for a simple discrete linear problem.

This paper considers the problem of estimation of classification error in pattern recognition. A theorem is presented to obtain the changes in the eigenvalues and eigenvectors of matrices of the form S 2 −1 S 1 , when there are changes of first order of smallness in the real symmetric matrices S i , i = 1, 2. Based on this theory a computational algorithm is developed for the estimation of classification error of Fisher classifier, using leaving groups out method.

The United States Air Force is currently developing an Advanced Airborne Command Post System. This system will provide the National Command Authorities and the Strategic Air Command a survivable command and control system during the pre-, trans- and post-attack phases of a general war. This paper presents a general description of the system, its interface with other systems, details on selected subsystems, and discusses potential growth capabilities.