• The tire
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• s.205
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• pp.42-42
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• 2000

타이어의 이상마모가 발생하는 원인은 여러 가지가 있으나 이번호에는 차량구조, 형식이나 바퀴주변장치가 원인이 되어 발생하는 이상마모 현상에 대하여 설명하고자 한다.

• 방재와보험
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• s.119
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• pp.14-18
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• 2007

세계의 이상기상은 조만간 우리에게 재난으로 다가올 것이고 우리나라는 이를 사전에 대비한 체계를 갖추어야 한다. 따라서 실제 이상기상으로 야기될 수 있는 재난의 유형과 그 심각성을 중심으로 향후 우리나라가 대처하기 위해 지금부터 준비하여야 하는 이상기상 관련 안전관리의 필요성을 논의하고자 한다.

• 대학교육
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• s.74
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• pp.100-106
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• 1995

• Journal of the Korean earth science society
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• v.38 no.4
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• pp.263-268
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• 2017

The determination algorithm of the location of a line source with strike and dip using the gravity gradient tensor on a single profile is proposed. We already proposed the determination of strike and dip in the previous paper and then, now we improved the algorithm to locate a line source after determining strike and dip. The strike and dip of the line source can be determined by rotating the gravity gradient tensor matrix as reducing 2 independent components. Using the ratio of remaining 2 components, the location can be determined by the least square manner of the pointing vectors on each observation point. A synthetic model is tested for proving the usefulness of the proposed algorithm.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.481-487
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• 2013

Purpose: The purpose of this study was to investigate the correlation between non-strabismic binocular dysfunctions and academic achievement for primary school children. Methods: A total of 1,123 parents and their children aged 8-13 years responded to the College of Optometrists in Vision Development Quality of Life (COVD-QOL) questionnaire. Among the all participants, 123 children who have ${\geq}20$ of visual symptom scores, no amblyopia, no strabismus, no any ocular and systemic pathology, and no contact lenses wearing were chosen for this study finally. Binocular functions were evaluated for final subjects. Results: Of 123 primary school children who have criteria-eligible symptoms 93 had non-strabismic binocular dysfunctions. Accommodative dysfunction was significantly correlated to subjects of science and English, and vergence dysfunction was also significantly correlated to Korean, mathematics, social science, science and English in the final subjects. Conclusions: Correlations between academic achievement and accommodative/vergence dysfunctions were statistically significant. Therefore, accommodative/vergence dysfunctions may be factors to affect academic achievement.

• The Korean Journal of Applied Statistics
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• v.34 no.3
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• pp.507-521
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• 2021

Detecting outliers among high-dimensional data encounters a challenging problem of screening the variables since relevant information is often contained in only a few of the variables. Otherwise, when a number of irrelevant variables are included in the data, the distances between all observations tend to become similar which leads to making the degree of outlierness of all observations alike. The subspace outlier detection method overcomes the problem by measuring the degree of outlierness of the observation based on the relevant subsets of the entire variables. In this paper, we survey recent subspace outlier detection techniques, classifying them into three major types according to the subspace selection method. And we summarize the techniques of each type based on how to select the relevant subspaces and how to measure the degree of outlierness. In addition, we introduce some computing tools for implementing the subspace outlier detection techniques and present results from the simulation study and real data analysis.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.223-228
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• 2022

In chemical processes, unintended faults can make serious accidents. To tackle them, proper fault diagnosis models should be designed to identify the root cause of faults. To design a fault diagnosis model, a process and its data should be analyzed. However, most previous researches in the field of fault diagnosis just handle the data set of benchmark processes simulated on commercial programs. It indicates that it is really hard to get fresh data sets on real processes. In this study, real faulty conditions of an industrial polystyrene process are tested. In this process, a runaway reaction occurred and this caused a large loss since operators were late aware of the occurrence of this accident. To design a proper fault diagnosis model, we analyzed this process and a real accident data set. At first, a mode classification model based on support vector machine (SVM) was trained and principal component analysis (PCA) model for each mode was constructed under normal operation conditions. The results show that a proposed model can quickly diagnose the occurrence of a fault and they indicate that this model is able to reduce the potential loss.

• Smart Media Journal
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• v.13 no.4
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• pp.48-56
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• 2024

In the livestock industry, detecting environmental outliers and predicting data are crucial tasks. Outliers in livestock environment data, typically gathered through time-series methods, can signal rapid changes in the environment and potential unexpected epidemics. Prompt detection and response to these outliers are essential to minimize stress in livestock and reduce economic losses for farmers by early detection of epidemic conditions. This study employs two methods to experiment and compare performances in setting thresholds that define outliers in livestock environment data outlier detection. The first method is an outlier detection using Mean Squared Error (MSE), and the second is an outlier detection using a Dynamic Threshold, which analyzes variability against the average value of previous data to identify outliers. The MSE-based method demonstrated a 94.98% accuracy rate, while the Dynamic Threshold method, which uses standard deviation, showed superior performance with 99.66% accuracy.

• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.801-807
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• 2024

Linear motion robots are devices that perform functions such as transferring parts or positioning devices, and require high precision. In companies that develop linear robot application systems, human workers are in charge of quality control and fault diagnosis of linear robots, and the result and accuracy of a fault diagnosis varies depending on the skill level of the person in charge. Recently, there have been many attempts to utilize artificial intelligence to diagnose faults in industrial devices. In this paper, we present a system that automatically diagnoses linear rail and ball screw misalignment of a linear robot using transfer learning. In industrial systems, it is difficult to obtain a lot of learning data, and this causes a data imbalance problem. In this case, a transfer learning model configured by retraining an established model is widely used. The information obtained by using an acceleration sensor and torque sensor was used, and its usefulness was evaluated for each case. After converting the signal obtained from the sensor into a spectrogram image, the type of abnormality was diagnosed using an image recognition artificial intelligence classifier. It is expected that the proposed method can be used not only for linear robots but also for diagnosing other industrial robots.

• Clinical and Experimental Pediatrics
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• v.45 no.3
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• pp.311-319
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• 2002

Purpose : We have performed this study to obtain reference data for the distribution of chromosomal aberrations in Korea. Methods : We analyzed 1,180 chromosomal study cases from Kwang ju Christian Hospital during the past 25 years. 756 cases suspected of characteristic chromosomal aberration syndromes and 424 cases with hermaphroditism, mild sexual abnormalities, multiple anomalies, or mental & growth retardation were included. Results : The male to female ratio of autosomal aberration syndromes was 1.2 : 1. 78.6% of autosomal aberrations were diagnosed under 1 year of age, whereas 89.8% of sex chromosomal aberrations were diagnosed over 12 years of age. Among 1,180 cases, 612 ones had chromosomal aberrations(51.9%) : 590 of 756 cases suspected of chromosomal aberration syndromes had aberrations( 78.0%), whereas 22 of 424 showing the above other features had aberrations(5.2%). Autosomal aberrations appeared in 514 cases(83.8%) and sex chromosomal aberrations appeared in 98 cases(16.2%). The most frequently observed abberation in autosomal aberrations was Down syndrome, followed by E, D, B, A and C group aberrations. The most common abberation in sex chromosomal aberrations was Turner syndrome, followed by Klinefelter syndrome and Fragile X syndrome. Conclusion : It is of vital importance that patients suspected of chromosomal aberrations undergo chromosomal analysis. Further advanced chromosomal staining and molecular genetic methods will raise the detection rate of chromosomal aberrations.