• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.98-105
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• 2000

In this study, we developed rotating machine vibration condition monitoring system based upon Windows NT and DSP Board. Developed system includes signal analysis module, trend monitoring and simple diagnosis using threshold value. Trend analysis and report generation are offered with database management tool which was developed in MS-ACCESS environment. Post-processor, based upon Matlab, is developed for vibration signal analysis and fault detection using statistical pattern recognition scheme based upon Bayes discrimination rule and neural networks. Concerning to Bayes discrimination rule, the developed system contains the linear discrimination rule with common covariance matrices and the quadratic discrimination rule under different covariance matrices. Also the system contains k-nearest neighbor method to directly estimate a posterior probability of each class. The result of case studies with the data acquired from Pyung-tak LNG pump and experimental setup show that the system developed in this research is very effective and useful.

• MALSORI
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• no.33_34
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• pp.91-98
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• 1997

Auditory discrimination which represents a very basic and important perceptual skill in children is a necessary condition for effective learning. It is necessary, therefore, to devise a standardized test tool for a reliable assessment of the auditory discrimination ability of children. The Korean Auditory Discrimination Test(KADT) is a tentative test tool that the authors have devised to meet such demand, i.e., to test the auditory discrimination ability of Korean children, both normal and hearing- and speech-impaired, between the ages of 4 and 8. The KADT consists of 40 pairs of words arranged in a systematic manner, of which thirty are 'minimal pairs' of words and the rest homophonous synonyms. The 30 minimal pairs are composed in such a way that major phonological contrasts involving consonants and vowels at initial, medial and final positions are duly represented. The test score will be determined by the number of right responses made by the children. Further attempts will be made to refine and improve KADT in future.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.119-125
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• 1999

This paper gives an overview of the various approaches to designing statistical pattern recognition scheme based on Bayes discrimination rule and the artificial neural networks for rotating machine condition classification. Concerning to Bayes discrimination rule, this paper contains the linear discrimination rule applied to classification into several multivariate normal distributions with common covariance matrices, the quadratic discrimination rule under different covariance matrices. Also we discribes k-nearest neighbor method to directly estimate a posterior probability of each class. Five features are extracted in time domain vibration signals. Employing these five features, statistical pattern classifier and neural networks have been established to detect defects on rotating machine. Four different cases of rotation machine were observed. The effects of k number and neural networks structures on monitoring performance have also been investigated. For the comparison of diagnosis performance of these two method, their recognition success rates are calculated form the test data. The result of experiment which classifies the rotating machine conditions using each method presents that the neural networks shows the highest recognition rate.

• International Journal of Safety
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• v.1 no.1
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• pp.28-35
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• 2002

Kullback Discrimination Information (KDI) is one of the pattern recognition methods. KDI defined as a measure of the mutual dissimilarity computed between two time series was studied for detection and classification of bearing flaking on outer-race and inner-races. To model the damages, the bearings in normal condition, outer-race flaking condition and inner-races flaking condition were provided. The vibration sensor was attached by the bearing housing. This produced the total 25 pieces of data each condition, and we chose the standard data and measure of distance between standard and tested data. It is difficult to detect the flaking because similar pulses come out when balls pass the defection point. The detection and classification method for inner and outer races are defected by KDI and nearest neighbor classification rule is proposed and its high performance is also shown.

• Journal of the Korean Applied Science and Technology
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• v.37 no.4
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• pp.996-1007
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• 2020

The purpose of this study was to investigate the general characteristics, working condition, discrimination experience and job engagement of office workers and to examine the effect of discrimination experience on job engagement. This study was the secondary analysis of date from the fifth Korean Working Conditions Survey and the subjects included 6,718 office workers. Collected data were analyzed using descriptive statistics, x²-test, t-test, and complex samples general linear model(CSGLM). As a result, job engagement was high when they never experienced discrimination. Based on the results of this study, in order to improve job engagement of office workers, manage to prevent discrimination in the workplace should be included.

• Korean Journal of Occupational Health Nursing
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• v.29 no.2
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• pp.160-171
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• 2020

Purpose: This study explored the association between workplace discrimination and violence and depressive symptoms among Korean employees. Methods: Data were obtained from the 4th Korean Working Condition Survey of 2014, which included 21,902 Korean employees. Depressive symptoms were measured using the WHO-5 Well-Being Index questionnaire scales. Results: A statistically significant relationship between workplace discrimination and workplace violence was found, and these two variables were also associated with depressive symptoms. After adjusting for variables such as sociodemographic characteristics, physical risk, and psychosocial working environment, workplace discrimination (OR=1.22, p<.001) and workplace violence (OR=1.69, p<.001) were both significantly associated with depressive symptoms. Conclusion: This study indicates that to promote employees' psychological health, systems and programs to prevent workplace discrimination and violence are needed. Development of these systems and programs should consider employees' experiences of workplace discrimination and workplace violence, sociodemographic characteristics, physical risk, and psychosocial working environments.

• Korean Journal of Cognitive Science
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• v.20 no.1
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• pp.29-49
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• 2009

The purpose of the present research was to examine whether the parietal pathway and the temporal pathway were responsible for the phenomena of the inhibition of return and the facilitation of return respectively and at what stage of the information processing they occurred. The response time and the ERPs(event-related potentials) were examined in the two conditions(the valid condition and the invalid condition) while subjects were doing detection task, location discrimination task, color discrimination task and orientation discrimination task in separate sessions. No significant response time difference was found between the valid and the invalid conditions when subjects did the detection task as well as the location discrimination task. However, significant response time difference was found when they did the color discrimination as well as the orientation discrimination task. Futhermore, there was a significant difference of ERP difference between the two conditions in the Pz area when subjects were doing location discrimination task and significant difference was found in the T7 area when they were doing color discrimination task and marginal difference was found in T7/T8 area when they were doing orientation discrimination task just before they responded. These results imply the possibility that both the inhibition of return and the facilitation of return occur in the parietal and in the temporal pathway respectively in the late stage of information processing.

• Journal of Agricultural Extension & Community Development
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• v.14 no.2
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• pp.471-491
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• 2007

The purpose of this study were (1) to thumbnail sketch of present general condition of foreigners and international marriage in Korea, (2) to study special trend of international marriage in rural Korea, particularly immigration connected with poverty, and (3) to focus on prospect of the problem of mixed-bloods, especially half blood children in rural Korea. Many of foreigners were treated discriminatingly, for example racial discrimination and wage discrimination. And discrimination to mixed-blood children will be happen in future. They are in a disadvantageous position because of economic status and appearances. Half blood children have korean nationality because one of his parent is korean. When they grow up and reach their the age of puberty and the age of working, they will resist to discrimination in working and marriage. I had examined precedent studies, and class theory in general, and to suggest it is time to looking for way of reduce social cost and way of coexistence.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.4
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• pp.212-216
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• 2013

As virtual reality technologies are advanced rapidly, how to render 3D objects across modalities is becoming an important issue. This study is therefore aimed to investigate human discriminability on the curvature of 3D polygonal surfaces with focusing on the vision and touch senses because they are most dominant when explore 3D shapes. For the study, we designed a psychophysical experiment using signal detection theory to determine curvature discrimination for three conditions: haptic only, visual only, and both haptic and visual. The results show that there is no statistically significant difference among the conditions although the threshold in the haptic condition is the lowest. The results also indicate that rendering using both visual and haptic channels could degrade the performance of discrimination on a 3D global shape. These results must be considered when a multimodal rendering system is designed in near future.

• Bulletin of the Korean Chemical Society
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• v.26 no.5
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• pp.769-775
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• 2005

An efficiency of Monte Carlo (MC) docking simulations was examined for the prediction of chiral discrimination by cyclodextrins. Docking simulations were performed with various computational parameters for the chiral discrimination of a series of 17 enantiomers by $\beta$-cyclodextrin ($\beta$-CD) or by 6-amino-6-deoxy-$\beta$-cyclodextrin (am-$\beta$-CD). A total of 30 sets of enantiomeric complexes were tested to find the optimal simulation parameters for accurate predictions. Rigid-body MC docking simulations gave more accurate predictions than flexible docking simulations. The accuracy was also affected by both the simulation temperature and the kind of force field. The prediction rate of chiral preference was improved by as much as 76.7% when rigid-body MC docking simulations were performed at low-temperatures (100 K) with a sugar22 parameter set in the CHARMM force field. Our approach for MC docking simulations suggested that the conformational rigidity of both the host and guest molecule, due to either the low-temperature or rigid-body docking condition, contributed greatly to the prediction of chiral discrimination.