The potential use of rudders as anti-roll devices has long been recognized. However, the possible interference of this secondary function of the rudder with its primary role as the steering mechanism has prevented, fo...
The potential use of rudders as anti-roll devices has long been recognized. However, the possible interference of this secondary function of the rudder with its primary role as the steering mechanism has prevented, for many years, the development of practical rudder roll stabilizers. The practical feasibility of rudder roll stabilization has, however, in recent years been demonstrated by two systems designed and developed for operational evaluation aboard two different U.S. C oast G uard Cutters, i.e., Jarvis and Mellon of the 3,000-ton, 378-foot HAMILTON Class. The authors describe the major components of the rudder roll stabilization (RRS) system, along with the design goals and methodology as applied to these first two prototypes. In addition, a brief history of the hardware development is provided in order to show some of the lessons learned. The near flawless performance of the prototypes over the past four years of operational use in the North Pacific is documented. Results from various sea trials and reports of the ship operators are cited and discussed. The paper concludes with a discussion of the costs and benefits of roll stabilization achieved using both a modern anti-roll fin system, as well as two different performance level RRS systems. The benefits of roll stabilization are demonstrated by the relative expansion in the operational envelopes of the USS OLIVER HAZARD PERRY (FFG-7) Class. The varying levels of roll stabilization suggest that the merits of fins and RRS systems are strongly dependent on mission requirements and the environment. The demonstrated performance of the reliable RRS system offers the naval ship acquisition manager a good economical stabilization system.
Causal source codes are defined. These include quantizers, delta modulators, differential pulse code modulators, and adaptive versions of these. Several types of causal codes are identified. For memoryless sources it ...
Causal source codes are defined. These include quantizers, delta modulators, differential pulse code modulators, and adaptive versions of these. Several types of causal codes are identified. For memoryless sources it is shown that the optimum performance attainable by causal codes can be achieved by memoryless codes or by time-sharing memoryless codes. This optimal performance can be evaluated straightforwardly.
This paper describes an evolving Arithmetic Design System (ADS) to support the quantitative evaluation of alternate number systems with respect to a given application and realization technology. A finite number system...
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We present a case study of the application of recently evolved structured VLSI design methodologies to the design and implementation of a simple VLSI quasi-serial inner product machine.
We present a case study of the application of recently evolved structured VLSI design methodologies to the design and implementation of a simple VLSI quasi-serial inner product machine.
This paper describes an evolving Arithmetic Design System (ADS) to support the quantitative evaluation of alternate number systems with respect to a given application and realization technology. In computer arithmetic...
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This paper describes an evolving Arithmetic Design System (ADS) to support the quantitative evaluation of alternate number systems with respect to a given application and realization technology. In computer arithmetic we are concerned with establishing a correspondence between abstract quantities (numbers) and some physical representation (symbols), and with simulating the operations on these symbols. The ADS is intended to help study the cost and performance of alternate simulations. A finite number system is a triple consisting of a symbol set (elements are called "digit-vectors"), an interpretation set, a mapping between these two sets, and a set of operators (digit-vector algorithms) defined on its symbol set. A set of these digit vector algorithms are proposed for conducting arithmetic design. A number system matrix defines the digit vector algorithm for numerous number systems and a method for computing time and space complexity of compositions of these algorithms is proposed. An example of how the system could be used to compare addition, with and without overflow detection, for three number systems is given.
During the FRAM II experiment in the Pole Abyssal Plain of the Eastern Arctic Ocean, an extensive program of refraction shooting was conducted. Multichannel data on an 800 × 800 m hydrophone array and on an ocean...
During the FRAM II experiment in the Pole Abyssal Plain of the Eastern Arctic Ocean, an extensive program of refraction shooting was conducted. Multichannel data on an 800 × 800 m hydrophone array and on an ocean bottom seismometer were obtained from shots deployed from a remote camp and by helicopter, at ranges up to 300 km. The multipath of the bottom interacting paths was resolved using high resolution velocity spectra. These spectra were used to determine (i) a crustal model for the seabed at the FRAM II site, (ii) the propagation loss and spreading for both the reflected and refracted bottom interacting paths, and (iii) conversion efficiencies of shear waves identifiable from the OBS. [Work supported by ONR.]
The feasibility of real-time digital filtering using dedicated state-of-the-art microcomputers of 8-bit wordlength is demonstrated. Implementations of Lynn's integer filter structures by means of wrap-around queue...
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The feasibility of real-time digital filtering using dedicated state-of-the-art microcomputers of 8-bit wordlength is demonstrated. Implementations of Lynn's integer filter structures by means of wrap-around queue data structures are shown to operate at sampling rates of over 8 kHz. An initial condition constraint unique to this filter class which must be satisfied to prevent inadvertent overflows or oscillations in microcomputers is discussed. The fast-filtering techniques are applied to the problem of calculating the average absolute value of a fast signal in real time.
Database management systems have evolved to the point of general acceptance and wide application;however a major problem still facmg the user is the effective utihzatlon of these systems. Important to achmving effecti...
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Real-time multiprogramming systems, in which a hardware processor is dynamically assigned to run multiple software processes each designed to control an important device (user), are considered. Each software process e...
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