• Proceedings of the KSR Conference
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• 2007.11a
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• pp.903-912
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• 2007

Faults of rotating parts of a train normally generate unexpected frequency band or impulsive sound[1] which has a period when it moves with a constant speed. The former can be detected by the moving frame acoustic holography method, which visualizes sound field that is generated by a moving and emitting pure tone or band limited noise source. We have attempted to apply the method to the latter case: the periodic impulsive sound which generate different signal compared with what can be measured by the band limited noise. The signal to noise ratio which determines the success of early fault detection must also be studied with the impulsive and moving signal. This research shows how the problems related with these issues can be resolved. The main idea is that periodic impulsive signal can be expressed by infinite set of discrete pure tones. This enables us to obtain lots of holograms that visualize periodic impulsive sound field including noise by using the moving frame acoustic holography method. Therefore holograms can be averaged to improve the signal to noise ratio until having reliable information that exhibits where the impulsive sources are. Theory and experiment by using the miniature vehicle are described [Work supported by BK21 & KRRI].

• Journal of the Korean Home Economics Association
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• v.48 no.8
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• pp.99-111
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• 2010

The purpose of this study was to identify the factors, which influence impulsive buying at duty-free shops. This involved an investigation into the effects of demographic characteristics, the types of purchased items, and the situational and emotional factors affecting impulsive purchasing behaviour in consumers, who had bought items from duty free shops in the past three years. The findings are as follows. Firstly, while beverage and cosmetic items were found to encourage impulse buying, in general demographic variables and type of product had only a slight influence. Secondly, the situational factors of price benefits, overseas luxury branding, and ease of access in the duty free shopping area all had a definite positive influence. Thirdly, with regard to emotional factors, positive emotion was found to have strong augmenting effect on impulsive purchasing. The findings can be used in the development of educational materials to prevent impulsive purchasing and promote sensible consumer behaviour.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.12
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• pp.4036-4043
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• 1996

When a high-speed railway train enters a tunnel, a compression wave is generated ahead of the train and propagates along the tunnel, compressing and accelerating the rest air in front of the wave. At the exit of the tunnel, an impulsive wave is emitted outward toward the surrounding, which causes a positive impulsive noise like a kind of sonic boom produced by a supersonic aircraft. With the advent of high-speed train, such an impulsive noise can be large enough to cause the noise problem, unless some attempts are made to alleviate its pressure levels. In the purpose of the impulsive noise reduction, the present study tested the effect of porous walls on the compression wave propagating into a model tunnel. Experimental results were obtained using a shock tube with an open end. The results showed that the cavity/porous wall is very effective for the compression wave with a large nonlinear effect. The porosity of 30% is most effective for attenuation and pressure gradient reduction of the compression wave front. Also the impulsive noise reduction increases with increasing the length and height of the cavity, compared with the tunnel equivalent diameter.

• The Journal of the Acoustical Society of Korea
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• v.30 no.2
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• pp.73-79
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• 2011

This paper presents a new impulsive noise detection algorithm in speech signal. The proposed method employs the frequency domain characteristic of the impulsive noise to improve the detection accuracy while avoiding the false-alarm problem by the pitch of the speech signal. Furthermore, we proposed time-frequency domain impulsive noise detector that utilizes both the time and frequency domain parameters which minimizes the false-alarm problem by mutually complementing each other. As the result, the proposed time-frequency domain detector shows the best performance with 99.33 % of detection accuracy and 1.49 % of false-alarm rate.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.7
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• pp.850-856
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• 2004

When a shock wave arrives at the open end of a tube, an impulsive wave is discharged from the tube exit and causes serious noise and vibration problems. In the current study, the effect of the cross-sectional area of a circular tube on the impulsive wave is investigated using computational methods. Marten-Yee's TVD scheme was employed to solve axisymmetric, unsteady, compressible Euler equations. With a change in the cross-sectional area of the tube, the Mach number of an incident shock wave is varied between 1.01 and 1.50. The results obtained show that the magnitude of the impulsive wave strongly depends upon the Mach number of the incident shock wave and the cross-sectional area of the tube. It is also found that for a given cross-sectional area of the tube, the impulse wave has strong directivity to the tube axis.

• Journal of Advanced Navigation Technology
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• v.7 no.1
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• pp.30-37
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• 2003

In this paper, we have analyzed the BER (Bit Error Rate) performance of MC-CDMA systems under indoor wireless environment with class A impulsive noise suggested by Middleton. For the performance evaluation, we considered from strong to weak impulsive noise characteristics. And we have evaluated the degree of performance improvement by using turbo code as a compensation technique to impulsive noise. From the result of analysis, it is found powerful performance improvement scheme must be adopted in the system under impulsive noise environment, and when turbo code scheme is adopted, system BER performance is improved by the $10^{-2}$. As the impulsive noise characteristics approaches AWGN characteristics, the degree of performance improvement by adopting turbo code become larger.

• The Journal of Information Systems
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• v.31 no.4
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• pp.209-232
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• 2022

Purpose In the current environment of online shopping, the cost for consumers to obtain the information they need is decreasing, and the price of products is becoming more transparent, leading to increased price competition among enterprises for similar products. Given the widespread usage of limited-time promotion as a marketing method for enterprises in the context of e-commerce, it is great meaning to study and reveal the internal influence mechanism of limited-time promotion on consumers' impulsive consumption. Design/methodology/approach Based on the S-O-R theory, this study constructs a model of consumers' impulsive consumption in the context of e-commerce from the perspective of perceived price discount, with evoking sense and pleasure as mediating variables and perceived time pressure as moderating variables. Findings The results show that perceived price discount has a significant positive impact on evoking sense and pleasure. Evoking sense has a significant positive impact on pleasure. Both evoking sense and pleasure have a significant positive impact on consumers' impulsive consumption. Meanwhile, perceived time pressure plays a significant moderating role between perceived price discount and evoking sense, between perceived price discount and pleasure, and between evoking sense and consumers' impulsive consumption. Finally, based on the above findings, this study provides effective suggestions for e-commerce participants in the formulation of limited-time promotion strategies.

• Journal of Distribution Research
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• v.7 no.1
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• pp.21-40
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• 2002

The purposes of this study were to examine the conceptual structure of consumer characteristics and marketing elements affecting impulsive buying behavior of the CATV home-shopper on fashion products, and to compare the differences of consumer characteristics and marketing elements between impulsive buying shoppers and non-impulsive buying shoppers in CATV home-shopping. We collected data from 263 females of CATV home-shoppers in Busan. Data were analyzed by factor analysis, t- test, $\chi$2-test, and discriminant analysis. The results showed that the exploratory tendency of CATV home-shoppers was consisted of Patronage-orientation, and Product- orientation. The marketing elements perceived by CATV home-shoppers were composed of Promotion, Product and Payment method. There were differences of consumer characteristics and marketing elements between impulsive buying shoppers and non impulsive buying shoppers. Especially, impulsive tendency of shoppers and promotion factor of marketing were significant variables in the impulsive buying behavior of CATV home-shopping. The results provide information about impulsive buying behavior in CATV home-shopping, useful to consumer behavior researchers and retailers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.99-105
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• 2010

The most frequently used noise model for the performance analysis of a communication system is additive white Gaussian noise. However impulsive noise model is more practical for the real communication environments, currently the performance analysis of a communication system in impulsive noise is increasing. In this paper, therefore, the performance of a cooperative system, which is recently one of the most intensive research topics, is derived in impulsive noise. We analytically derive and compare the performance of two opportunistic cooperative diversity systems which have an amplify-and-forward (AF) relaying or a decode-and-forward (DF) relaying. It is noticed that the impulsive noise component is increases with decreasing the average number of impulses in impulsive noise, consequently the performance of two systems is degraded in high SNR region. Also it is shown that the performance of the opportunistic cooperative system with DF relaying is superior to that with AF relaying.

• Journal of the Korean Home Economics Association
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• v.33 no.5
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• pp.75-88
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• 1995

The objectives of this study were to classify the contents of clothing shopping orientation, to group women into shopper types, and to examine the differences in clothing purchase criteria according to the shopper types. Samples were 335 women(20-49 years of age) in Seoul, Korea. The data were analyzed using factor analysis, cluster analysis, one-way ANOVA, Duncan's multiple range test, X2 test, paired t-test, multiple regression analysis. The results of the study were the followings. 1. Five factors of clothing shopping orientation derived by factor analysis : F.1 'impulsive shopping' ; F.2 'rational shopping' ; F.3 'independent shopping' ; F.4 'economic shopping' ; F.5 'convenient shopping'. Three shopper types were classified by cluster analysis of the 5 factors : T.1 'convenient shopper' ; T.2 'impulsive shopper' ; T.3 'rational shopper'. 2. Significant differences were found among the 3 shopper types in all clothing purchase criteria. Rational shopper perceived all purchase criteria as more important than did the other 2 types. Impulsive shopper perceived 'fashion', 'attractiveness', 'style', and 'bland' as more important than did convenient shopper. 3. Married women and unemployed women were more distributed in rational shopper, while the unmarried and the employed more in impulsive shopper. Impulsive shopper used more credit care, purchased suits and blouses at department store and brand specialty store more than did rational shopper. Rational shopper purchased at discount store and wholesale store more than did impulsive shopper. 4. Women assessed 'color and fabric design' as most important in suit and blouse purchase criteria. 'Care' was perceived more important in blouses than in suits, and the other 9 purchase criteria(fashion, attractiveness, style, color and fabric design, fabric, durability, costruction, comfort, and brand) were perceived more important in suits than in blouses. 5. Rational and economic shopping orientation scores were higher in suit purchase than in blouse, while impulsive, independent, and convenient shopping orientation scores were higher in blouse purchase. 6. Post-purchase suit satisfaction was influenced by rational shopping orientation, educational level, style, income, and comfort. The explanatory power of the 5 variables was 17.2%. Post-purchase blouse satisfaction was influenced by style, care, rational shopping orientation, and independent shopping orientation. The explanatory power of the 4 variables was 10.2%.