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  • Frequency variability of the vertical profile of the first normal mode of pressure and particle velocity in a shallow water waveguide

    The article is devoted to the analysis of the vertical structure of the acoustic pressure field and the first-mode particle velocity in a hydroacoustic waveguide in shallow water. A waveguide consisting of a water layer with a constant sound velocity profile, a transition layer, and a half-space is considered. The acoustic properties of the transition layer are assumed to be frequency dependent. Formulas are derived that describe the vertical profile of the normal mode of a particle velocity. The transformation of the vertical profile of the first mode with increasing frequency is analyzed. The phase difference relations between the normal mode of acoustic pressure and particle velocity are analyzed. A relationship is established between the change in the vertical structure of the normal modes of pressure and particle velocity and the acoustic properties of the transition layer.

    Keywords: normal modes, particle velocity, seabed, attenuation coefficient

  • Propagation of a narrow-band impulse in a shallow water hydroacoustic waveguide

    The article considered the propagation of a long impulse signal in a hydroacoustic waveguide. A solution is given for a replica of a impulse signal in the second approximation of the dispersion theory. The propagation of a single-mode and multimode impulse in a Pekeris waveguide with a bottom in the form of an absorbing half-space is simulated. The acoustic properties of the half-space correspond to medium sand with an average grain size 0,3 mm. The result of the solution in the second approximation of the dispersion theory is compared with the result of the simulation of the impulse replica obtained as a convolution of the input signal with the impulse response of the waveguide. The disadvantages of the solution in the second approximation of the dispersion theory are shown and analyzed. It is shown that the theory of dispersion incorrectly reproduces the transients when the signal is switched on and off in cases where the signal frequency lies near the critical frequency of the first or second mode. It is shown that the theory of dispersion correctly reproduces the envelope of a multimode impulse signal.

    Keywords: impulse signal, normal modes, group velocity, dispersion theory, intramode dispersion, intermode dispersion

  • Affective and cognitive components of socio-cultural attitudes

    The relationship between the affective and cognitive components of attitudes in relation to a surrounding cultural landscape is investigated on a concrete example. The functions of distribution of perception level for cultural infrastructure are calculated on the basis of the experimental results obtained in May-June, 2015 by questioning among students of DonSTU. The emotional component was determined by technology of semantic differential. The primary data were processed in the nonlinear model developed within the catastrophe theory. The cognitive component was found by a technique of direct poll with the subsequent factorization by a classical method and allocation of key parameter. The difference in affective and cognitive perception of cultural infrastructure is discovered. At the group level the number of respondents which declared positive and strongly positive cognitive assessment are 10% more than for emotional one. With neutral perception, on the contrary, is 7% more on an affective indicator. In general on group the cognitive assessment is overestimated, the average level of emotional perception of infrastructure is 0,14 and cognitive is 0,27 (on a scale from -1 to +1). At the individual level these indicators among themselves practically don't correlate (Pearson's coefficient is 0,2).The received results say that the standard technique of direct poll at research of a cultural landscape is limited and it should be supplemented with the analysis of emotional perception. Such analysis for the considered audience is provided in work.

    Keywords: cultural attitudes, affective component, cognitive component, questioning, semantic differential, nonlinear model, theory of accidents, function of distribution, perception assessment

  • Cognitive cultural and leisure installations of students of DGTU on the middle of 2015.

    Results of poll of students of the Don state university about a cultural complex of the Rostov region are given in article. The main cultural and leisure installations of respondents, their relation to cultural infrastructure of Rostov-on-Don and area, their main cultural interests are shown. On the basis of these data conclusions are drawn on the level of satisfaction of cultural requirements of students.

    Keywords: cultural complex of the Rostov region, cultural requirements, sociocultural elements, cultural services