Neurally Based Measurement and Evaluation of Environmental Noise

Abstract

Aims & ScopeThe meaning of "Mathematics for Industry" (sometimes abbreviated as MI or MfI) is different from that of "Mathematics in Industry" (or of "Industrial Mathematics"). The latter is restrictive: it tends to be identified with the actual mathematics that specifically arises in the daily management and operation of manufacturing. The former, however, denotes a new research field in mathematics that may serve as a foundation for creating future technologies. This concept was born from the integration and reorganization of pure and applied mathematics in the present day into a fluid and versatile form capable of stimulating awareness of the importance of mathematics in industry, as well as responding to the needs of industrial technologies. The history of this integration and reorganization indicates that this basic idea will someday find increasing utility. Mathematics can be a key technology in modern society.The series aims to promote this trend by (1) providing comprehensive content on applications of mathematics, especially to industry technologies via various types of scientific research, (2) introducing basic, useful, necessary and crucial knowledge for several applications through concrete subjects, and (3) introducing new research results and developments for applications of mathematics in the real world. These points may provide the basis for opening a new mathematicsoriented technological world and even new research fields of mathematics.More information about this series at

Subjective Preferences for Birdsong and Insect Song in Equal Sound Pressure Level

“…Fifteen (eleven males; four females) and sixteen (eleven males; five females) participants with normal hearing and an age range of between 20 and 41 years (median age of 24.5 and 24.4 years and standard deviation of 7.2 and 6.9) took part in the subjective preference for birdsongs and insect songs, respectively. It is considered, from our previous studies [9], that at least ten participants are necessary for the statistical power and generality of the results of these types of psychoacoustic experiments. Informed consent was obtained from each participant after the nature of the study was explained.…”

“…Parameters obtained from the autocorrelation function (ACF) have been proposed for noise and sound quality evaluations [9,14]. To determine ACF parameters, the normalized ACF of the signals recorded by the microphone, p(t), is defined by:…”

“…2T is the integration interval and p'(t) = p(t)*s e (t), where s e (t) is the ear sensitivity corresponding to an A-weighted filtering, for the sake of expedience [9,14]. Normalized ACF is calculated using the geometric mean of the energy at zero and the energy at zero + τ to ensure that the normalized ACF satisfies 0 ≤ ϕ(τ) ≤ 1.…”

“…τ 1 and ϕ 1 are defined as the delay time and the amplitude of the first maximum peak. τ 1 and ϕ 1 are related to the perceived pitch and the pitch strength of sounds, respectively [9,15]. Higher values of τ 1 and ϕ 1 indicate that the sound has a lower or a stronger pitch, respectively.…”

“…The width of the first decay, W ϕ(0) , is defined using the delay time interval at a normalized ACF value of 0.5. W ϕ(0) is equivalent to the spectral centroid [9]. Higher values of W ϕ(0) indicate that the sound includes a higher proportion of low-frequency components.…”