Search

The object of this report is to supply the theoretical bases for certain useful and computable approximations to the problem of transmission loss in hydroacoustic propagation. These approximations involve a knowledge of two acoustic profiles, one at the emitter and the other at the receiver and only require general assumptions of the intermediate behavior of sound speed. In this sense they form a 'second approximation'--the 'first approximation' being the familiar one based on the assumption of an acoustic profile independent of range. The ranges are long enough to involve multiple-path transmission, caustics, and the complications produced by many convergence zones. The random factors and incomplete knowledge of the medium of transmission are not only explicitly acknowledged but are made to play a central role in the discussion: they give rise to a somewhat novel model and open up possibilities of simplification of averages, etc., See also AD-A017 006.

In the analysis of air terminal congestion, two distinct but interlocking systems have to be considered: the air traffic control system, with its sensors, communication links, computers and displays; and the mechanical system composed of the runways, the ground and air space surrounding them, and the aircraft in their various states of takeoff and waiting for takeoff, of landing, joining the landing pattern, in stacks and so on. The tools of analysis are concerned with the second of these systems, in which the phenomena of congestion are in fact the phenomena of waiting lines and their interactions. The final object aimed at in the report is a set of tools for calculating the quantitative effects on the performance of the air terminal of various assumed conditions, operational options, and suggested technical improvements. The effects on the performance are to be expressed in terms of throughput rates, delay reductions, and diminished numbers of aircraft not accomodated. (Author)

The long-range objective of the program is to develop tools and techniques to define, measure, and predict the quantitative capacity of an air traffic control system, which can then be used in analytical studies in support of long-range plans, management decisions, and system performance evaluations. A first approximation to a functional description of the present air traffic control system, largely free of descriptions of equipment or methods now used to implement the functions, was prepared. Several approaches to the quantitative use of measures of safety as system variables were formulated. The mathematical theory of time-dependent queues was found to be applicable to air traffic control system capacity problems. Some elementary applications, chiefly illustrative of methods, were made. It was concluded that: (1) A functional description of air traffic control which is applicable to a wide range of system concepts, including the present system and many suggested variations and alternatives, is feasible; (2) The mathematical theory of time-varying queues is an important, useful tool; (3) The quantitative study of safety is highly relevant to ATC capacity, but must be studied indirectly rather than through accident statics; and (4) Simple, straightforward definitions of concepts, such as capacity, demand, delay, and safety, are unlikely, but the need for them can be satisfied by families of less comprehensive terms. (Author)

When a probability distribution of a target is given, the problem of detecting it by a given method involving the progressive expenditure of effort, will be harder or easier according to the nature of the distribution. A natural measure of the degree of difficulty of detection by the method in question is the expected value of the quantity of effort used up to the (random) moment of detection--assuming that the most effective use of the effort is made at each moment. The first object of this investigation is to show the connection between the present concept when the search is done as a procedure of successive dichotomies until localization--to a pre-stated order of precision--is obtained. The connection with the classical theory of information (entropy and cross- entropy) is shown. The second object of this investigation is to apply the method to the case in which the law of random search is applied progressively and optimally to the search for a target in a linear, planar, or spacial region (or in r-space)., Report on Stochastic Processes in Certain Naval Operations. Presented at Operations Research Society of America, Chicago, Ill., November 1, 1967.

The feasibility was studied of devising indices which could be used to assess the performance of an ATC terminal area. These indices are to be based on easily available data and designed to reflect system degradation, safety and system workload. The report presents a prototype analysis of data relating to the Boston Terminal Area. It is concluded that indices can be devised and their relationship established with environmental variables such as congestion, weather, equipment outrages, etc. These relations show which of these variables are the most significant and their relative magnitudes in influencing performance. The report also discusses the role of simulation in terminal area improvement evaluation. An unambiguous definition of operational delay is proposed. Finally, a cost/benefit paradigm is presented for the Boston Terminal Area. Portions of this document are not fully legible.