• 전자공학회논문지B
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• 제30B권12호
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• pp.12-20
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• 1993

In a conventional adaptive echo canceller, an ADF(Adaptive Digital Filter) with TDL(Tapped-Delay Line) structure modelling the echo path uses the LMS(Least Mean Square) algorithm to compute the coefficients, and NET detector using energy comparison method prevents the ADF to update the coefficients during the periods of the NET signal presence. The convergence speed of the LMS algorithm depends on the eigenvalue spread ratio of the reference signal and NET detector using the energy comparison method yields poor detection performance if the magnitude of the NET signal is small. This paper presents a new adaptive echo canceller which uses the pre-whitening filter to improve the convergence speed of the LMS algorithm. The pre-whitening filter is realized by using a low-order lattice predictor. Also, a new NET signal detection algorithm is presented, where the start point of the NET signal is detected by computing the cross-correlation coefficient between the primary input and the ADF output while the end point is detected by using the energy comparison method. The simulation results show that the convergence speed of the proposed adaptive echo canceller is faster than that of the conventional echo canceller and the cross-correlation coefficient yields more accurate detection of the start point of the NET signal.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 추계학술대회
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• pp.474-476
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• 2009

반향제거 또는 채널등화와 같은 무선통신 시스템에서 적응필터링은 매우 실용적이다. 적응필터의 계수갱신을 위해 사용되는 적응 알고리즘의 수렴성능은 입력신호의 상관도와 적응필터의 길이에 의존한다. 높은 입력상관도와 긴 길이의 적응필터는 수렴성능을 저하하므로 이러한 문제점을 해결하기 위해 최근 부밴드 구조에서 입력상관도를 사전제거하고 적응필터 계수를 갱신하는 부밴드 AP 알고리즘이 제안되었다. 본 논문에서는 다중제한조건을 갖는 부밴드 AP 알고리즘의 수렴성능 해석방법을 제시한다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.159-159
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• 2022

Soil represents a substantial component within the global carbon cycle and small changes in the SOC stock may result in large changes of atmospheric CO₂ particularly over tens to hundreds of years. In this study, we aim to (i) evaluate the SOC stock in the topsoil 0 - 15 cm from soil physical and chemical characteristics and (ii) find the correlation of SOC and soil organic matter (SOM) for national-scale in South Korea. First of all, based on the characteristics of the soil to calculate the soil hydraulic properties, SOC stock is the SOC mass per unit area for a given depth. It depends on bulk density (BD-g/cm³), SOC content (%), the depth of topsoil (cm), and gravel content (%). Due to insufficient data on BD observation, we establish a correlation between BD and SOC content, sand content, clay content parameter. Next, we present linear and non-linear regression models of BD and the interrelationship between SOC and SOM using a linear regression model and determine the conversion factor for them, comparing with Van Bemmelen 1890's factor value for the country scale. The results obtained, helps managers come up with suitable solutions to conserve land resources.

• Journal of information and communication convergence engineering
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• 제13권2호
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• pp.105-112
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• 2015

The estimation of missing sensor values is an important problem in sensor network applications, but the existing approaches have some limitations, such as the limitations of application scope and estimation accuracy. Therefore, in this paper, we propose a new estimation model based on a spatial-temporal correlation analysis (STCAM). STCAM can make full use of spatial and temporal correlations and can recognize whether the sensor parameters have a spatial correlation or a temporal correlation, and whether the missing sensor data are continuous. According to the recognition results, STCAM can choose one of the most suitable algorithms from among linear interpolation algorithm of temporal correlation analysis (TCA-LI), multiple regression algorithm of temporal correlation analysis (TCA-MR), spatial correlation analysis (SCA), spatial-temporal correlation analysis (STCA) to estimate the missing sensor data. STCAM was evaluated over Intel lab dataset and a traffic dataset, and the simulation experiment results show that STCAM has good estimation accuracy.

• 융합정보논문지
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• 제7권6호
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• pp.79-87
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• 2017

본 연구의 목적은 융복합 수강생의 의사소통 인식과 의사소통능력, 의사소통 자기효능감의 관계를 확인하기 위한 융합연구이다. 2017년 3월13일부터 24일까지 S대학 융복합 수강생을 대상으로 자발적으로 동의한 학생에게 연구목적과 방법을 설명하고 128부의 설문지를 수집하였다. 분석은 IBM SPSS 21.0 프로그램을 이용하여 기술통계, T-test, ANOVA, Spearman correlation coefficient를 이용하였고 도구는 Likert 5점 척도이다. 연구결과 연구대상자의 의사소통 인식 5점 만점 평균 $3.50{\pm}.41$, 의사소통 능력 $3.32{\pm}.38$, 의사소통 자기효능감 $3.00{\pm}.40$으로 나타났다. 연구대상자의 의사소통 인식과 의사소통 능력(r=.633, p<0.01), 의사소통 인식도와 자기효능감(r=.336, p<0.01), 의사소통 능력과 자기효능감(r=.480, p<0.01) 모두 유의한 양의 상관관계를 나타냈다. 따라서 융복합수강생의 자기효능감 수준을 향상시키는 프로그램이 적용된다면 의사소통 능력을 더 높일 수 있을 것으로 기대한다.

• 융복합기술연구소 논문집
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• 제4권2호
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• pp.27-33
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• 2014

To well design the solar energy system using solar energy, the correlation to calculate solar irradiation is basically needed. So, this study was performed to reveal the relationships between the solar irradiation and four meteorological observation data(dry bulb temperature, relative humidity, sunshine duration, and cloud cover) which are different from previous other researches. And then, we finally proposed the first order non-linear correlation from the measured solar irradiation using four meteorological observation data with MINITAB. To show the deviation of the solar irradiation between measured and calculated, this study compared using the daily total solar irradiance and the maximum peak value. From those results, the calculation error was estimated about maximum 25.4% for the daily total solar irradiance. The error of the solar irradiation between measured and calculated was made from the curve fitting error. So, solar irradiation prediction correlation with higher accuracy can be obtained using 2nd or higher order terms with four meteorological observation data.

• Structural Engineering and Mechanics
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• 제20권3호
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• pp.293-312
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• 2005

In this paper, free vibration of rotating beam with random properties is studied. The cross-sectional area, elasticity modulus, moment of inertia, shear modulus and density are modeled as random fields and the rotational speed as a random variable. To study uncertainty, stochastic finite element method based on second order perturbation method is applied. To discretize random fields, the three methods of midpoint, interpolation and local average are applied and compared. The effects of rotational speed, setting angle, random property variances, discretization scheme, number of elements, correlation of random fields, correlation function form and correlation length on "Coefficient of Variation" (C.O.V.) of first mode eigenvalue are investigated completely. To determine the significant random properties on the variation of first mode eigenvalue the sensitivity analysis is performed. The results are studied for both Timoshenko and Bernoulli-Euler rotating beam. It is shown that the C.O.V. of first mode eigenvalue of Timoshenko and Bernoulli-Euler rotating beams are approximately identical. Also, compared to uncorrelated random fields, the correlated case has larger C.O.V. value. Another important result is, where correlation length is small, the convergence rate is lower and more number of elements are necessary for convergence of final response.

• 한국운동역학회지
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• 제30권3호
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• pp.217-223
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• 2020

Objective: The purpose of this study was to analyze the effect of postural sway on the kinematic variables of the putter head during golf putting and to provide information to the importance of postural sway control in the putting stroke for novice golfers. Method: The center of pressure (CoP) and Kinematics variables of the putter head were calculated during 2 m flat golf putting using 8 motion capture cameras (250 Hz) and 2 force plate (1,000 Hz). SPSS 24.0 was used to perform Pearson's correlation coefficient and simple regression analysis, and the statistically significance level was set to .05. Results: As a result of analyzing the correlation between CoP variables and the putter head rotation angle, the CoP moving length, CoP moving range (ML direction), and CoP moving velocity (ML direction) showed a positive correlation with the putter head rotation angle (yaw axis) and were statistically significant. Conclusion: Therefore, In order to perform the accurate putting stroke maintaining the ball's directionality, it is determined that it is important to control posture sway in the ML directions by minimizing the movement and velocity of the CoP.

• 국제물리치료학회지
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• 제12권1호
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• pp.2286-2294
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• 2021

Background: Exercise is necessary for the health of companion dogs. It is necessary to determine the relationship between height, weight, age and amount of exercise for the purpose of companion dog's health. Objectives: A survey was conducted in this study to small-dog owners living in Yongin city, Gyeonggi-do about their canine healthcare awareness. Design: Questionnaire design. Methods: The questionnaire was composed of exercise amount, type of exercise, and the necessity of exercise, general health condition, and environment. A total of 139 survey results were obtained. The average value of each item was analyzed and expressed in terms of frequency and percentage. Then, Pearson's correlation coefficients were used to find the relationship between these items. Results: The weight and height were not shown to have a significant difference in the amount of exercise in the results. The weight had a weak positive correlation with "exercise time of canine per day". The age had a weak negative correlation with "the number of canine exercise per week" and "frequency of canine exercise per day", while it had a weak positive correlation with "self-assessment of canine lack of exercise". Conclusion: Based on this study, it is believed that in the future, various environments where dogs can exercise are believed to be necessary for the era of convergence.

• International journal of advanced smart convergence
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• 제12권4호
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• pp.407-417
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• 2023

The purpose of this study is to identify the level of safety perception, ethical awareness, and safety activities of nursing students for patients, and to identify the correlation and impact between them. The research design is a descriptive survey study, and the subject of the study were 197 nursing college students in G City. Safety perception, ethical awareness, and safety activity tools were used for, and the data collection period was from October 17 to 28 in 2022. T-test, one-way ANOVA, Pearson's correlation coefficient, Regression analysis were used to analyze data. The result of the study indicated that the average level of safety perception of nursing students was 3.72 points, the average ethical awareness of patients, professional work, and cooperators perceived by nursing students was 3.04 points, and the safety activities of nursing students were 4.20 points. In the case of safety awareness and ethics awareness, r=.327, a significant positive correlation, in the case of safety awareness and safety activities, r=.399, significant positive correlation, ethics awareness and safety activities as r=.296. And so on these results showed that high safety perception increases safety activities, and high ethical awareness increases safety activities. Therefore, we need practical and step-by-step convergence education to equip nursing students with patient safety nursing capabilities. To this end, a safer environment will be created if the social support network for the systematic application of safety education is well formed.