• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.54.1-54.1
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• 2015

We report results of investigation of amplitude calibration for very long baseline interferometry (VLBI) observations with Korean VLBI Network (KVN). Amplitude correction factors are estimated based on comparison of KVN observations at 22 GHz correlated by Daejeon hardware correlator and DiFX software correlator in Korea Astronomy and Space Science Institue (KASI) with Very Long Baseline Array (VLBA) observations at 22 GHz by DiFX software correlator in National Radio Astronomy Observatory (NRAO). We used the observations for compact radio sources, 3C 454.3 and NRAO 512 which are almost unresolved for baselines in a range of 350-477 km. VLBA visibility data of the sources observed with similar baselines as KVN are selected, fringe-fitted, calibrated, and compared in their amplitudes. We found that visibility amplitudes of KVN observations should be corrected by factors of 1.14 and 1.40 when correlated by DiFX and Daejeon correlators, respectively. These correction factors are attributed to the combination of two steps of 2-bit quantization in KVN observing systems and characteristics of Daejeon correlator.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.73-76
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• 2001

It is well-known that the convergence rate gets worse when an input signal to an adaptive filter is correlated. In this paper we propose a new adaptive filtering algorithm that makes the convergence rate highly improved even for highly correlated input signals. By introducing an orthogonal constraint between successive input signal vectors, we overcome the slow convergence problem caused by the correlated input signal. Simulation results show that the proposed algorithm yields highly improved convergence speed and excellent tracking capability under both time-invariant and time varying environments, while keeping both computation and implementation simple.

• The Korean Journal of Pain
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• v.10 no.1
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• pp.69-72
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• 1997

Background : This study was designed to determine if cervical epidural depth has any correlation with age, height, weight, ponderal index and neck clrcunference. Methods : Data was obtained from 102 patients successfully anesthetized with cervical epidural block. Patients were categorized into 4 groups: male C6-7, male C7-T1, female C6-7, female C7-T1 then statistically compared and analyzed. Results : The mean and standard deviation of epidural depth of male C6-7, male C&-T1, female C6-7, female C7-T1 groups were respectively as follows: 41.1+/-6.0, 47.1+/-5.6, 37.9+/-6.0, 46.4+/-5.6 mm. The results showed cervical epidural depth is well correlated with body weight and ponderal index; moderately correlated with neck circumference: slightly correlated with age; no correlation with height.

• International Journal of Highway Engineering
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• v.18 no.4
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• pp.77-82
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• 2016

PURPOSES : This paper proposes a reliability index for the safety evaluation of freeway sections. It establishes a reliability index as a safety surrogate on freeways considering speeds and speed dispersions. METHODS : We collated values of design elements including radii, curve lengths, vertical slopes (absolute values), superelevations, and vertical slopes from seven freeway sections in Korea. We also collected data about driving speeds, traffic accidents, and their deviations. We established a reliability index using these variables. RESULTS : The average radii, curve lengths, and superelevations are highly correlated with the incidence of traffic accidents. Deviations in radius and curve lengths show an especially high correlation. The reliability index, derived from speed and speed dispersions of the seven freeway sections, also correlated highly with accidents with a correlation index of 0.63. CONCLUSIONS : Since the reliability index obtained from speed and speed dispersions are highly correlated with traffic accidents, we conclude that a reliability index can be a safety surrogate on freeways considering speeds and speed dispersions together in terms of design and operational levels.

• Korean Journal of Human Ecology
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• v.23 no.3
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• pp.409-420
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• 2014

The purpose of this study was to explore the effects of mother-child interaction and child's social behaviors on child's peer acceptance. Participants were 108 4- to 5-year-old preschoolers(58 boys, 50 girls) and their mothers. Data were analyzed by descriptive statistics, correlation analysis and stepwise multiple regression analysis. The major findings are summarized as follows: (1) mother-child interaction are generally correlated with child's peer acceptance. And child's prosocial behavior was positively correlated with child's peer acceptance, whereas child's aggressive behavior, asocial behavior and hyperactive-distractible behavior were negatively correlated with child's peer acceptance. (2) The most influential factor on child's peer acceptance was child's experience in session, the next influential factor was child's hyperactive-distractible behavior and the last influential factor was asocial behavior.

• English Language & Literature Teaching
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• v.17 no.1
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• pp.101-124
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• 2011

This paper investigated the relationships among Korean EFL learners' listening anxiety, listening strategy use, and listening proficiency. One hundred and forty four Korean college students who were enrolled in the required practical English classes participated in this study. Questionnaires related to students' listening strategy use and listening anxiety were administered and a TOEIC listening comprehension test was given to measure the students' listening proficiency. The one-way ANOVA was used to analyze the data. The findings of this study are that the students' listening performance is positively correlated with their strategy use and negatively correlated with their anxiety level, and their strategy use is negatively correlated with their anxiety level. The results suggest that successful learning will occur when anxiety is reduced and when the use of strategies is encouraged more often. The pedagogical implications for EFL educators and teachers are described.

• Korean journal of food and cookery science
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• v.11 no.3
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• pp.295-302
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• 1995

The purposes of the study were to identify the operational characteristics in employee feeding facilities, and to examine the correlations of productivity and these characteristics. A questionnaire was developed and mailed the 500 dietitians in employee feeding facilities in Seoul and Kyoungki Do. Usable questionnaires were received from 117 respondents for a response rate of 23.4％. The questionnaire was designed to determine the productivity index and to investigate the relationship between operational characteristics and productivity index. The questionnaire was contained 2 parts with a total of 16 statements. Data were analyzed for descriptive statistics and Pearson correlation analysis using SPSS/PC programs. The average productivity indices of 117 facilities were 6.91 meals/hr. Total meals served/week was significantly correlated to the productivity index (r=0.441, p < 0.001). No of average servings per meal, percentage of convenience food use, average minutes for service/day, and employment in professional practice of dietitian were also positively correlated, while food cost was negatively correlated to the productivity.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.2
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• pp.90-94
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• 2008

It is well-blown that the convergence rate gets worse when an input signal to an adaptive filter is correlated. In this paper we propose a new adaptive filtering algorithm that makes the convergence rate much improved even for highly correlated input signals. By introducing an orthogonal constraint between successive input signal vectors we overcome the slow convergence problem of the LMS algorithm with the correlated input signal. Simulation results show that the proposed algerian yields fast convergence speed and excellent tracking capability under both time-invariant and time-varying environments, while keeping both computation and implementation simple.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.99-101
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• 2006

Auto-Cross Correlated time series (ACTS) model was constructed by using the backpropagation neural network. The performance of ACTS model was evaluated with sensor information collected from a large volume, industrial plasma-enhanced chemical vapor deposition system. A total of 18 sensor information were collected. The effect of inclusion of past and future information were examined. For all but three sensor information with a large data variance demonstrated a prediction error less than 3%. By integrating ACTS model into equipment software, process quality can be more stringently monitored while improving device throughput.

• Journal of the Korean Home Economics Association
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• v.42 no.12 s.202
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• pp.1-14
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• 2004

The purpose of this study was to identify how characteristics of young children (sex, age, birth order, temperament), parents (education level, employed or unemployed mother, mother's parenting behavior), and family (income) relate to young children's stress levels and to examine the relative effects of these variables on young children's stress. The subjects for this study were 287 young children, aged from 3 to 5 years old, selected from kindergartens and day-care centers in Busan. Data were analyzed with t-test, ANOVA, correlation, and multiple regression. The results were as follows. (1) Young children's stress was correlated with young children's sex, age, birth order and temperament. (2) Young children's stress was correlated with parenting behaviors. (3) Young children's stress was not correlated with income. (4) Children's emotionality and maternal overprotective behavior were the most significant variables affecting the stress experienced by boys and girls, respectively. (5) Maternal overprotective behavior variable affected both sibling and only children's stress.