• Title/Summary/Keyword: frequency and correlation analysis

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A Study on the Structure for the Improvement of Vibration Characteristics of a Vehicle Seatbelt (자동차 시트벨트의 진동특성 개선을 위한 구조에 관한 연구)

  • Kim, Chang-Hee;Oh, Chea-Eun;Kim, Tea-Woo;Song, Chul-Woo;Lee, Seok-Soon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.2
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    • pp.97-102
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    • 2020
  • To prevent vibration of a vehicle's interior parts due to external impacts, the vehicle should be designed to reduce vibration and increase rigidity. In this paper, we conducted a vehicle test in which the vibration characteristics of a seatbelt resulting from the impact of a person closing a car door were measured and analyzed. A correlation analysis was performed using the finite analysis method. Based on this, a sensitivity analysis was performed, and an improved model was designed. We compared the natural frequencies and mode shapes of the improved and the initial models, which confirmed that the natural frequency of the improved model was more than 10 Hz higher than that of the initial model. Moreover, the response frequency of the improved model was three times higher than the input frequency applied in the vehicle test.

Experimental test on bridge jointed twin-towered buildings to stochastic wind loads

  • Ni, Z.H.;He, C.K.;Xie, Z.N.;Shi, B.Q.;Chen, D.J.
    • Wind and Structures
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    • v.4 no.1
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    • pp.63-72
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    • 2001
  • This paper presents results of a study on wind loads and wind induced dynamic response of bridge jointed twin-towered buildings. Utilizing the high-frequency force balance technique, the drag and moment coefficients measured in wind tunnel tests, and the maximum acceleration rms values on the top floor of towers, are analyzed to examine the influence of building's plan shapes and of intervals between towers. The alongwind, acrosswind and torsional modal force spectra are investigated for generic bridge jointed twin-towered building models which cover twin squares, twin rhombuses, twin triangles, twin triangles with sharp corners cut off, twin rectangles and individual rectangle with the same outline aspect ratio as the twin rectangles. The analysis of the statistical correlation among three components of the aerodynamic force corroborated that the correlation between acrosswind and torsional forces is significant for bridge jointed twin-towered buildings.

The Correlation between Clothing Style and Hair Style related to Fashion Image (패션이미지에 따른 의복스타일과 헤어스타일의 상관성)

  • Lee, Hyo-Sook;Park, Sook-Hyun
    • Journal of the Korean Society of Fashion and Beauty
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    • v.2 no.3 s.3
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    • pp.44-59
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    • 2004
  • The purpose of this study was to find out proper evaluative words according to fashion image and to identify the correlation between clothing style and hair style related to fashion image. The questionnaire was used to collect data. 326 female aged between 23 to 40 were selected for the subjects of this study. The data were analyzed by frequency, factor analysis, pearsons correlation. The results of this study were as follows. 1. Evaluative words for each fashion image were selected by factor analysis. modern image intellectual, cold, urbane, simple, straight. elegance image : graceful, dignified, refined, decorous, luxurious. romantic image : cute, lovely, girlish, feminine, romantic. natural image : natural, comfortable, gentle, intimate, soft. casual image : energetic, active, free, cheerful, vivid. avant-garde image : experimental, strange, creative, avant-garde, irregular. 2. Correlation between clothing style image and hair style image ; clothing style and hair style was positively correlated. with the same image in case of modern, romantic, casual, elegance and avantgarde but natural image of clothing style was correlated with the natural, elegance, romantic, modern image of hair style. 3. The most suitable hair style for the clothing style according to fashion image : The clothing style of a particular image was matched best with the hair style of the same image.

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A Study on Performance Analysis for Error Probability in SWSK Systems

  • Jeong, Tae-Il;Moon, Kwang-Seok;Kim, Jong-Nam
    • Journal of information and communication convergence engineering
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    • v.9 no.5
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    • pp.556-561
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    • 2011
  • This paper presents a new method for shift keying using the combination of scaling function and wavelet named scaling wavelet shift keying (SWSK). An algorithm for SWSK modulation is carried out where the scaling function and the wavelet are encoded to 1 and 0 in accordance with the binary input, respectively. Signal energy, correlation coefficient and error probability of SWSK are derived from error probability of frequency shift keying(FSK). The performance is analyzed in terms of error probability and it is simulated in accordance with the kind of the wavelet. Based on the results, we can conclude that the proposed scheme is superior to the performance of the conventional schemes.

The Analysis of Relationship between Academic Achievement Level of Concept Learning and Error Type in Online Programming Course (온라인 프로그래밍 개념학습 성취수준과 오류유형과의 관계 분석)

  • Kim, Jiseon;Kim, Yungsik
    • The Journal of Korean Association of Computer Education
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    • v.17 no.5
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    • pp.43-51
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    • 2014
  • This study has purpose on analyzing the error types which are identified after middle and high school students perform the online programming assignments and also has the purpose on the analysis of correlation between the frequency of error occurrence according to academic achievement level in programming concept learning and types of errors analyzed previously. For this study, the syntax, logical, and coding errors are analyzed from the performed results of programming research assignment for 88 students. Analyzed results show that the logical error has the highest occurrence rate of 69.3% among three types of errors, and it has been shown meaningful difference in the frequency of error occurrence between three achievement level groups of high, middle, and low. In the correlation analysis of achievement level and error types, it shows negative relationship between logical error and coding error, and therefore it can be concluded that as achievement level is higher, both logical and coding errors tend to occur less. In the correlation analysis in error types, it shows positive relationship between syntax error and coding error.

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An interior noise characteristic analysis of Busan Metro Line 3 (부산 도시철도 3 호선 실내소음 특성분석)

  • Ahn, Chan-Woo;Hong, Do-Kwan;Han, Geun-Jo;Gang, Hyeon-Uk;Lee, Kwon-Soon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2010.10a
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    • pp.362-367
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    • 2010
  • This paper deals with the correlation between the interior noise and the floor vibration of the train from rolling, impulse and friction in Busan Metro line 3. The correlation is verified by sound and vibration measurement causing friction between the railway and the wheel. If ANC(Active Noise Control) system can reduce 5 dB in below 500 Hz, the sound pressure level of the whole band pass can be reduced about 1.8-4.8 dB in squeal noise. Curve squeal noise is the intense high frequency tonal that can occur when a railway vehicle transverses a curve. The frequency range is from around 500 to almost 20,000 Hz, with noise levels up to about 15 dB in curve.

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A Study on the Acoustic Fault Detection System of Insulators from Their Radiation Noises

  • Park, Kyu-Chil;Yoon, Jong-Rak
    • Journal of information and communication convergence engineering
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    • v.9 no.5
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    • pp.510-514
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    • 2011
  • To detect the insulator in the fault state on the electric poles, we first measured radiation sounds from normal state insulators and error state insulators in the anechoic chamber. We processed the signals in frequency domain to find the features with filter bank, narrow band and wide band analysis. So we could found two apparent results from their frequency spectrums - one was 120Hz harmonic components, the other was high average noise level than normal state ones. Then we also introduced a technique for the direction detection of the fault state insulator using the cross correlation from the three dimensional array microphones. To eliminate the noise signal from unexpected directions, we suggested the zero padding technique in cross correlation function. From these, we could conclude that acoustic fault detection techniques are useful of the detection of insulators' faults and the estimation of the direction of the fault state insulators.

The study of the relationship among perceived risk of apparel purchase, control, and impulse buying - Focusing on internet shopping mall consumers - (의류구매위험지각, 통제, 충동구매 간의 관계 연구 - 인터넷쇼핑몰 소비자를 중심으로 -)

  • Chung, Mi Sil
    • Korean Journal of Human Ecology
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    • v.23 no.5
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    • pp.873-890
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    • 2014
  • The purpose of this study was to examine the relationship among consumer's perceived risk of apparel purchase in internet shopping mall, control, and impulse buying. The subjects were 319 female college students in Gyeongsang provinces. The obtained data were analyzed by reliability analysis, analysis of frequency, factor analysis, cluster analysis, one-way ANOVA, Duncan's multiple range test, correlation analysis, and t-test. The major results of this study were as follows: First, three factors of consumer's perceived risk of apparel purchase in internet shopping mall were identified: size risk, trust risk, and social/psychological risk. Second, the subjects were categorized into three different types of groups according to perceived risk: high perceived risk type, middle perceived risk type, and low perceived risk type. Third, three control(self-control, goal-control, and desire for control) and three impulse buying(impulsive buying for showing off, impulsive buying for excitement, and impulsive buying due to memory) were identified. Fourth, there was significant difference between strong control group and weak control group on three factors of impulse buying. Fifth, a significant positive correlation was found size risk and three factors of control and a significant negative correlation was found self-control and three factors of impulse buying.

Cognitive Evaluation on Body Exposure of Female Clothing (여성의 신체노출의상에 대한 인지적 평가)

  • 조은영;홍병숙
    • Journal of the Korean Society of Clothing and Textiles
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    • v.19 no.5
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    • pp.723-737
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    • 1995
  • The purposes of this study were to investigate 1) the difference of cognitive evaluation on body exposure of female clothing, ann 2) purchase frequency and intention of wearing according to demographic variables. The instrument of this study consisted of response scale and stimuli. Thirty three items of 7.point Likert scale were developed to measure cognitive evaluation of the people who responded. The stimuli were 7 types of clothing, differing exposure parts and style on line drawing. The sample included 450 subjects, consisting of 231 in Seoul and 219 in Chun-nam Province. Statistics applied for analysis were frequency, percentage, mean, standard deviation, correlation, t-test, F-test, Duncan's multiple range test, factor analysis. The Results were: 1. Constructing factors of cognitive evaluation consisted of elegance, sensuality, attraction, individuality. There were significant differences in every factor on each types of clothing. 2. The evaluation toward each types of clothing was influenced by the subjects' sex, age, and residence. 3. Purchase frequency and intention of female subjects' wearing were very low, and there were significant differences on demographic variables.

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Analysis of the Wounding-Healing Themes in Sandplay Therapy Process for Children with Emotional Instability and Attention Deficit Children (정서불안 아동과 주의력 결핍 아동의 모래놀이치료 과정에서 표현된 상처와 치유 주제에 대한 분석)

  • Kim, Sun Suk;Kim, Ki Hyun
    • Human Ecology Research
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    • v.54 no.6
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    • pp.631-642
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    • 2016
  • This study analyzed of the themes (wounding and healing); concerning the Sandplay therapy process applied to children with emotional instability and attention deficit problems. The subjects of the study were 30 elementary school children who agreed to a personal-interview with the author. They all were families of receiving basic livelihood welfare living in the same county. After the preliminary analysis, the main study data collected from subjects was analyzed by variance (t-test), frequency analysis, and correlation analysis using the standard table modified in accordance with Mitchell's classification system. Particular attention was made in the analyses of the characteristics of the subjects as members of low-income families. As the Sandplay therapy proceeded, it became evident that the wounding area showed a low frequency while the healing area featured a high frequency, and confirmed (as in previous studies) that the Sandplay therapy would be effective for children with emotional instability as well as for those with attention deficit problems. The analysis of difference between the types of children with both problems revealed that Sandplay therapy was more effective for children with emotional instability than for those with attention deficit problems. The analysis also revealed that Sandplay therapy was more effective for girls than for boys.