• 대한전자공학회논문지
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• 제25권4호
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• pp.447-452
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• 1988

This paper proposes a hybrid image coding in order to improve the coding performance by combining the BTC with the DPCM. And utilizing the human perceptual characteristics, a new objective image quality evaluation method has been proposed to obtain an excellent result in good agreement with the subjective quality evaluation. A hyb-1 method consisting of the DPCM and the AMBTC has retained a good picture quality at the bit rate of 1.5 bits/pel. A hyb-3 method combining the EBTC-3 with the DPCM has scarcely degraded the picture quality compared with the original image at the bit rate of 2.1 bits/pel. A newly proposed mehtod of picture quality evaluation accumulating a blocky noise at the edge block and an impulsive noise at the flat block selectively has been coincident with the subjective evaluation of quality.

• 한국음향학회지
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• 제19권5호
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• pp.27-34
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• 2000

This paper deals with speech enhancement methods using the wavelet transform. A cycle-spinning scheme and undecimated wavelet transform are used for denoising of speech signals, and then their results are compared with that of the conventional wavelet transform. We apply soft-thresholding technique for removing additive background noise from noisy speech. The symlets 8-tap wavelet and pyramid algorithm are used for the wavelet transform. Performance assessments based on average SNR, cepstral distance and informal subjective listening test are carried out. Experimental results demonstrate that both cycle-spinning denoising(CSD) method and undecimated wavelet denoising(CWD) method outperform conventional wavelet denoising(UWD) method in objective performance measure as welt as subjective listening test. The two methods also show less "clicks" that usually appears in the neighborhood of signal discontinuities.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.611-616
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• 2003

The headphone is regarded as the most effective means for reproducing 3-dimentional virtual sound due to its channel separation property. However, there still exist several serious problems in headphone reproduction, such as, 'front-back confusion' and in-head localization'. These well-known problems are in general assessed by the subjective test that is based on human judgment. In this paper, an objective test is conducted in parallel with the subject test in order to validate the objective reproduction performance. Such a combined approach may be a more scientific and systematic approach to the reproduction performance.

• 디지털산업정보학회논문지
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• 제15권1호
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• pp.99-107
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• 2019

Retinex-based image enhancement is a technique that utilizes the property that the human visual characteristics are sensitive to the difference from the surrounding pixel value rather than the pixel value itself. These Retinex-based algorithms show different characteristics of the improved image depending on the applied color space or gamma correction. In this paper, we set eight different experimental conditions according to the application of color space and gamma correction, and analyze the objective and subjective performance of each Retinex based image enhancement algorithm and apply it to the implementation of Retinex based algorithm. In the case of gamma correction, quantitative low entropy images and low contrast images are obtained. The application of Retinex technique in HSI color space rather than RGB color space is found to be high in overall subjective image quality as well as maintaining color.

• 한국학교ㆍ지역보건교육학회지
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• 제17권1호
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• pp.101-112
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• 2016

Objectives: The purpose of this study was to examine the association between participation in physical activities (PA) and subjective well-being. Methods: We analyzed the data from Korean Youth Risk Behavior Web-based Survey, 2013 containing 36,655 and 35,780 for male and female students respectively. Study variables included PA, participation in physical education class, participation in team sports and subjective well-being. Control variables were school type, socio-economic status, level of parent education, living with parent, academic performance, delinquent behaviors, depression and perceived health. For this study, descriptive analysis, Chi-square test, and multivariate logistic regression analysis were performed. Results: Among boys, after adjusting for control variables, PA (past 7 days 0 time reference group vs. over 4 times: OR 1.306), physical education class (past 7 days 0 time reference group vs. over 3 times: OR 1.140), and team sports (no team reference group vs. 2 team: OR 1.206) were associated with subjective well-being. Among girls, control variables were adjusted. PA (past 7 days 0 time reference group vs over 4 times: OR 1.244), physical education class (past 7 days 0 time reference group vs. over 3 times: OR 1.161), and team sports (no team reference group vs. 2 team: OR 1.181) were associated with subjective well-being. Conclusions: Participation in physical activities may help adolescent promote their life satisfaction. Thus, education experts should develop various exercise curriculums to encourage participation in physical activities.

• 대한인간공학회지
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• 제33권6호
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• pp.553-563
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• 2014

Objective: The purpose of this study was to evaluate the effect of gender (male, female) and grip spans (45, 50, 60, 70, 80mm) on total grip strength, resultant force, finger force and subjective discomfort rating. Background: In order to prevent musculoskeletal disorders, studies of hand tools need to be preceded based on grip strength, finger force, and subjective discomfort rating. However, experimental apparatus using tools such as pliers that reflect the actual work place was almost non-existent. Method: Fifty-Two (26 males and 26 females) participants were recruited from the student population. In this study, a pair of revised pliers, which can change grip span from 45 to 80mm was applied to estimate total grip strength, resultant force and individual finger forces. All participants were asked to exert a maximum grip force with three repetitions, and to report the subjective discomfort rating for five grip spans of pliers (45, 50, 60, 70, 80mm). Results: There were significant differences of total grip strength, resultant force, individual finger forces and subjective discomfort rating according to grip span. The lowest total grip strength was obtained from the grip span of 80mm for both genders. For resultant force, the highest resultant force was exerted at grip spans of 50, 60 and 70mm for females and 50 and 60mm for males. The lowest subjective discomfort rating was observed in the 50mm for both genders. Conclusion: Based on the result, 50mm and 60mm grip spans which provide the highest force and lowest discomfort rating might be recommendable for the male and female pliers users. Application: The findings of this study can provide guidelines on designing a hand tool to help to reduce hand-related musculoskeletal disorders and obtain better performance.

• 한국치위생학회지
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• 제16권3호
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• pp.347-353
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• 2016

Objectives: The purpose of the study is to investigate the dental fear and related factors of dental hygienists using dental fear survey. Methods: A self-reported questionnaire was completed by 279 dental hygienists from January 15 to March 28, 2015. The study instrument was dental fear survey. Data were analyzed using SPSS 19.0 program by t-test, one way ANOVA and stepwise multiple regression analysis. The questionnaire included general characteristics of the subjects, subjective oral health status, use of dental care services, subjective oral health status, and recent dental treatment. Results: Alcohol consumption was the most influential factor to the dental fear. The subjective status of oral health and direct pain sense also contributed to the dental fear. Conclusions: To reduce the dental fear, it is important to have high confidence toward the dental treatment performance in the dental hygienists.

• 한국소음진동공학회논문집
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• 제15권7호
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• pp.821-828
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• 2005

In our life, we have used many digital appliances. They help us to improve the quality of life but sometimes give us unsatisfactory result. Because they produce specific noise. Especially vacuum cleaner produce much noise that is very annoying. So we need to study what sound metrics affect human sensibility. In this paper, we develop sound quality index for vacuum cleaner using the sound quality metrics defined in psychoacoustics. First, we carry out the subjective evaluation of vacuum cleaner sound to verify what vacuum sound feels good to human. And then artificial neural network estimated the complexity and the nonlinear characteristics of the relations between subjective evaluation and sound metrics. Finally the ANN is trained repeatedly to have a good performance for sound qualify index of the vacuum cleaner. As a result, the sound quality index of vacuum cleaner has a correlation of $93.5\%$ between the subjective evaluation and ANN. So, there exist three factors that Is loudness, sharpness, roughness which affect the sound quality of vacuum cleaner.

• 한국자동차공학회논문집
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• 제14권1호
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• pp.167-175
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• 2006

Directional stability is important performance in vehicle and tire design. The current methods to analyze this is generally based on linear concept. Using the existing concept, it cannot realistically explain the subjective assessment at all because it is hard to practically represent the nonlinear behaviour of a complex vehicle system in reality. In this paper, new method to analyze directional stability is introduced. At first, directional stability of vehicle is categorized into yaw, rear axle, and roll stability. In order to objectify these items, driver perceptual parameters based on subjective assessment are used. Using the perceptual parameters, it can successfully explain the transient maneuver of vehicle and extract objective parameters for directional stability. Finally, these objective parameters are successfully validated through two handling tests, lane change and severe lane change. The correlation results show that there exists a good correlation between subjective assessment and the proposed objective parameters.

• International Journal of Advanced Culture Technology
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• 제8권2호
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• pp.101-108
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• 2020

One difficulty in language learning is the training of reading ability. The improvement on this ability directly affects the process and effect of language learning. At the same time, there are numerous difficulties in actual learning and teaching. Depending on current research, there is two ideas that can utilize to enhance the reading efficiency of learners. One is to amend objective factors; the other is to change subjective factors. Compared with the two ideas, idiosyncratic factors are more manipulable and controllable, so it is more valuable to conduct researches on this. But among the many subjective factors, the degree of their effectiveness is not the same, so this article attempts to compare and analyze the driving effects of two important subjective factors (peer-driven and task-driven) on reading performance. The results show that both factors can have a positive impact on reading comprehension, but different in driving effects. The task-driven has obvious short-term effectiveness; while peer-driven needs to establish its long-term effect on the basis of early coordination and cooperation among team members. Therefore, in order to maximize the achievement of learning, it is necessary to combine strengths and avoid weaknesses according to the characteristics of two factors, so as to help learners improve reading ability most efficiently.