Thesis (M.Sc.D.)--Boston University, School of Graduate Dentistry, 1972. Endodontics. / Bibliography included.

No description available.

No description available.

This dissertation presents a new framework, trace-automata, for verifying hybrid systems. In addition, a simple, general theory of abstraction is presented, based on the idea of approximations that are liberal or conservative with respect to an abstraction function. This theory gives rise to a sound technique whereby hybrid systems are verified by constructing discrete approximations of both the implementation and the specification, and verifying that the approximate implementation satisfies the approximate specification. Trace-automata are language accepting, infinite tape automata, extended to allow multiple tapes, and to allow tapes that consist of continuous traces over the reals, as well as tapes that consist of sequences of discrete symbols. Hybrid systems are represented by automata that read some continuous tapes and some discrete tapes. Trace-automata are used to represent both the implementation and the specification of the system to be verified. Verification corresponds to demonstrating that the language accepted by the implementation is contained in that accepted by the specification. Hybrid systems are verified by constructing and verifying discrete approximations. Abstraction functions map continuous traces to discrete sequences. A liberal approximation of the system implementation is verified against a conservative approximation of the system specification. From this verification, it can be concluded that the original hybrid model satisfies the original specification. The dissertation describes a general technique for constructing discrete, liberal approximations of trace-automata representing differential equations and inclusions. In addition, trace-automata themselves can encode abstraction functions, with the result that trace-automata language containment can also be used to establish that an approximation is liberal or conservative as the case may be. These techniques are illustrated with an example verification based upon the Philips Audio Control Protocol with two agents, each capable of both transmitting and receiving. The verification is novel in that it is based upon a detailed model of the analog electrical behaviour of the bus.

No description available.

This thesis is focused upon the development of the computer as a communication medium in history. To accomplish this, the computer is understood as constructed by language and technology where these are in turn grounded upon their roles as forms of cultural mediation. As methodology is of paramount importance, the digital medium is heuristically employed to discuss the epistemic and phenomenological significance of communications media. The more general inference therefore concerns the role of socially constructed media in the fabric of cultural development. In addressing this concern, the paper finds that communications media stand as the repositories of knowledge in the form of artificial memory and figurative technique. The computer then, as a medium in history, may arguably be declared as a paradigmatic instantiation of this role.

Thesis (M.S.)--University of Texas at Dallas, 2007. / Includes vita. Includes bibliographical references (leaves 70-72)

Thesis (Ph.D.)--University of Adelaide, Dept. of Computer Science, 2003. / Also available in an electronic version.

Thesis (Ph.D.)--University of Adelaide, Dept. of Computer Science. / Also available in a print form.

The ultimate measure of performance of any communication system is the subjective quality of the received message. In this thesis, the subjective quality of the output of a differential pulse code modulation (DPCM) system was measured as a function of the number of bits of quantization L, the speech bandwidth W, the ratio r of the sampling frequency fs to the Nyquist frequency 2W, and the number of feedback samples N. For previous-sample feedback (N = 1) the maximum subjective quality was obtained as a function of the bit rate R = 2rWL. The optimum sampling rate .was found to be the Nyquist rate; the improvement afforded by increasing fs over 2W was more than offset by the required increase in bit rate. Noise in the feedback loop caused by dc offset errors and noise present in the output of the feedback coefficient amplifiers prevented a thorough investigation of two- and three- sample feedback, although some results were obtained. The subjective quality of delta modulated (ΔM) speech was obtained vs r and W, and the quality of amplitude modulated (ΔM) speech was measured as a function of W and channel signal-to-noise ratio. A technique was then devised to use the AM results to estimate the subjective quality of phase modulated (PM) speech. A comparison was then made of the capabilities of PCM, DPCM, AM, single sideband-AM (SSB-AM), double sideband-AM (DSB-AM), and PM. It was found that when the available channel capacity is small, SSB-AM and DSB-AM are subjectively better than PCM', DPCM, and ΔM. However, for high quality speech communication, DPCM requires less channel capacity than PCM, ΔM, DSB-AM, SSB-AM or PM. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate