Showing papers by "Polytechnic University of Turin published in 1970"

Review of Aluminum Foam Applications in Architecture

Abstract: The application of aluminum foam materials is increasing rapidly due to the high demand during the last decades. This research presents an overview of the characteristics and architectural applications of aluminum foam materials. Moreover, it represents the most relevant properties, in particular, physical and mechanical aspects and figures out the prospects and growth rate of these materials in architectures by considering the economic benefits. Besides, based on these specific characterizations, the most valuable applications along with advantageous in architectural works are discussed.

A flexible real-time recognizer of spoken words for man-machine communication

Abstract: A relatively simple real-time recognizer of spoken words is described. The main characteristics of this system are the following: (1) the vocabulary of accepted words is settled with simple operations on the panel of the machine; (2) the system is quasi-adaptive in the sense that the characteristic parameters of a given word uttered by a certain speaker can be measured and displayed on a set of Nixie tubes, and it is very easy (operating on the keyboard) to fit the recognizer to the speaker according to the displayed data; (3) at present, a maximum of 15 words can be classified, but, owing to the modularity of the system, other units can be added in order to enlarge the accepted vocabulary. The coder consists of a bank of active filters and a set of circuits translating spectral information into a set of binary digits. The processor is composed (a) of a set of combinational units which evaluate the Hamming distance of the input patterns from the characteristic sequences of phonemes or other “tracts” of words; (b) of a set of sequential units which complete the classification of the uttered word by analysing the time evolutions of the combinational network outputs. The panel controls which make it possible to fix the accepted vocabulary and to adapt the recognizer to the speaker operate on the connections between combinational and sequential units and on the operation parameters of all the units. The machine, used for recognizing the ten digits from 0 to 9 and five other words spoken in Italian, reaches an efficiency larger than 99% on condition of its being previously adapted to the speaker. Programmed according to the average characteristics of male speakers and for classifying words spoken by voices not used in the preceding stage of learning, it reaches average efficiencies of about 90%. (from 85 to 99%. for a given speaker),

Study of the propagation of a torsional wave in a curved wire

Abstract: The problem of the propagation of a torsional wave in a curved wire is examined. The displacements with a natural and with a forced curvature are calculated and the corresponding dispersion relations are obtained on the basis of a purely elastic model. The results are discussed in connexion with the problem of the propagation of a signal in a wire-type acoustic delay line and compared with the results previously obtained by other workers.

Computer optimisation of cascaded noncommensurable-line lowpass filters

Abstract: The performance of lowpass filters composed of cascaded noncommensurable-line elements is improved by a computer; among the different characteristics of the response of the filter, a remarkable width of the stopband may be obtained.

Analysis and synthesis of cascaded noncommensurable transmission lines, shunted by lumped capacitances

Abstract: Cascaded noncommensurable line elements, shunted by lumped capacitances, are considered, and necessary and sufficient conditions for the synthesis are derived from the study of the impedance function in a special set of points without using the multivariable-real-positive-function concept. An exhaustive example is given.

Tables and graphs for designing digital Chebyshev filters

Abstract: The authors draw attention to the availability of numerical tables and graphs for design by the conventional deduction of the z transform from a given squared magnitude function.

Analysis and synthesis of cascaded noncommensurable Ozaki-Ishii sections

Abstract: Cascaded noncommensurable Ozaki-Ishii sections are considered, and the necessary and sufficient conditions for the synthesis are derived from the study of the impedance function in a special set of points without using the multivariable-real-positive-function concept. An exhaustive example is given.

Line radiation in non local thermodynamic equilibrium

Abstract: This paper deals with the problem of line radiation in conditions of non thermodynamic equilibrium and applies the results obtained to the study of the imprisonment of resonance radiation. It was found that the excited level, and by consequence the resonance radiation, decays in two ways in competition each other: one is a diffusive decay, due to the fact that the gas is generally very thick for frequencies near the center of the absorption line, and the other is an exponential decay due to the far “wings” of the absorption coefficient, where the gas is optically thin.

Realisability conditions of cascaded and shunt noncommensurable element networks

Abstract: Necessary and sufficient conditions are studied for the cascaded and shunt noncommensurable line-element networks examining the input admittance in a particular point set.

The Virk's criterion on the onset of dilute polymer solution phenomena

Abstract: The Virk's criterion on the onset of the Toms phenomenon in dilute polymer solution is shortly considered; a correlation parameter based on the time hypothesis is indicated, which is modified with respect to the usual similar parameter in that dependence of the intrinsic viscosity on the shear rate is taken into account. It is shown an energetic interpretation of such a parameter.