The booming index has been developed recently to evaluate the sound characteristics of passenger cars. Previous work maintained that booming sound quality is related to loudness and sharpness -the sound metrics used in psychoacoustics -and that the booming index is developed by using the loudness and sharpness for a signal within whole frequencies between 20 Hz and 20 kHz. In the present paper, the booming sound quality was found to be e ectively related to the loudness at frequencies below 200 Hz; thus the booming index is updated by using the loudness of the signal ltered by the low pass lter at frequencies under 200 Hz. The relationship between the booming index and the sound metric is identi ed by an arti cial neural network (ANN ). Interior sounds of 10 passenger cars were measured, and 21 persons subjectively evaluated the booming sound qualities for these interior sounds. Throughout this research, it was found that there is a high correlation between the results of these evaluations and the output of a neural network. The updated booming index has been successfully applied to the objective evaluation of the booming sound quality of massproduced passenger cars.

The gear whine sound of an axle system is one of the most important sound qualities in a sports utility vehicle (SUV). Previous work has shown that, because of masking effects, it is difficult to evaluate the gear whine sound objectively by using only the A-weighted sound pressure level. In this paper, the characteristics of the axle-gear whine sound were first investigated on the basis of synthetic sound technology, and a new objective evaluation method for this sound was developed by using sound metrics, which are the psychoacoustic parameters, and the artificial neural network (ANN) used for the modelling of the correlation between objective and subjective evaluation. This model developed by using ANN was applied to the objective evaluation of the axle-gear whine sound for real SUVs and the output of the model was compared with subjective evaluation. The results indicate a good correlation of over 90 per cent between the subjective and objective evaluations.

No abstract

The high prevalence of obesity is a major public health issue and contributes to the 'double burden' of disease in developing countries. Early exposure to poor nutrition may cause metabolic adaptations that, when accompanied by exposure to 'affluent' nutrition, may increase the risk for obesity and other metabolic disorders. The aim of this study was to determine differences in energy metabolism and nutritional status between normal-height and growth-retarded North Korean children living in South Korea. A total of 29 children were recruited and underwent measurements of resting energy expenditure (REE), respiratory quotient (RQ), anthropometrics and dietary intake. There was no difference in REE or any assessment of obesity between the growth-retarded and normal-height children. Children who were classified as growth retarded (HAZ<-1.0) or stunted (HAZ<-2.0) had a significantly higher RQ (β=0.036 or 0.060, respectively, P=0.018 or 0.016), independent of sex, age, fat-free mass, fat mass and food quotient, compared with children with normal height. The results from this study, the first from an Asian population, add to the growing body of literature suggesting that undernutrition early in life results in adaptations in energy metabolism that favor fat deposition, increasing the risk of stunted children becoming overweight or obese later in life. Continued research on this topic is warranted, given the continued rise in the prevalence of the double burden in transitional countries.

A centrifugal turbo blower is one of the important parts used for generating electric power in a fuel cell electric vehicle (FCEV). The impeller blades of the centrifugal turbo blower must rotate at a high speed to generate electric power. The unbalance and asymmetry of the rotating parts, such as impeller blades, become causes of the heavy vibration of the centrifugal turbo blower. This vibration is transmitted to the chassis frame of the FCEV through vibration isolators and becomes one of the major sources of interior noise in the FCEV. Therefore, the vibration generated from a centrifugal turbo blower should be attenuated properly to reduce the interior noise. To achieve this effectively, quantification of the vibration energy flow through the isolators is necessary, since it gives information on the quantification of the vibrational energy flow from the centrifugal turbo blower to the chassis frame. Information on the vibrational power flow at each vibration isolator identifies the vibration transmission path. In this paper, a simple equation is derived to calculate the vibration power flow through each vibration isolator. With this equation, the vibrational power flow through each isolator is numerically simulated. In this simulation, the vibration generated from the centrifugal turbo blower is predicted using the multi-body dynamic analysis of a three-dimensional model of the centrifugal turbo blower based on computer-aided engineering. These simulated results are confirmed by measurement of the vibration power flow generated from the centrifugal turbo blower in a laboratory.