• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.305-310
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• 1999

본 논문에서는 기존의 선형 견인 어레이 방법인 FFTSA기법에서의 여러 가지 환경적 요인에 대한 입사각 추정 성능의 변화에 대해서 고찰하여 보았다. 즉, 시간 및 공간적 코히어런스 주기 변화에 대한 추정 성능 변화와 견인 센서 어레이가 가져야 하는 직선 경로에서 주위의 환경적 요인으로 인해 직선 방향을 중심으로 이탈된 발진 경로, 또는 진동경로가 발생되는 시스템 에러주기 변화에 대한 추정 성능의 변화에 대해 컴퓨터 시뮬레이션을 통하여 입사각 추정 성능의 변화를 살펴보았다. 또한 비선형 특성을 지니는 견인 배열 센서 어레이인 Conformal array를 FFTSA기법에 적용했을 경우 환경적 요인에 의한 입사각 추정 성능의 변화를 컴퓨터 시뮬레이션을 통하여 기존의 FFTSA기법과 비교하여 보았다.

• Journal of Sasang Constitutional Medicine
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• v.8 no.1
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• pp.247-294
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• 1996

By means of the statistical data which has been collected with newly revised QSCC made use of the outpatient group examined at Kyung-Hee Medical Center and an open ordinary person group, the author proceeded statistical analysis for the validation study of the revised questionnaire itself. First, check the accurate discrimination rate by performing discriminant analysis on the statistical data of the patient group. And next, sought T-score by applying the norms gained in process of standadization of the open ordinary person group to the Sasang scale score of the outpatient group and investigated the distinctive feature between the subpopulations which was devided in the process of multivarite cluster analysis. The result was summarized as follows ; 1. The validity of the questionnaire was established through the fact that the accurate discrimination rate the ratio between predicted group and actual group was figured out 70.08%. 2. At the profile analysis the response to the relevant scale showed notable upward tendency in each constitutional group and therefore it seems to be pertinent in the field of constitutional discrimination. 3. In the observation of the power of expression through the profile analysis of each constitutional group the Soyang group demonstrated the most remarkable outcome, the Soeum group was the most inferior and the Taieum group revealed a sort of dual property. 4. What is called the group of seceder out of three subpopulation of each constitutional group distinguished definitely from the contrasted groups at the point of the distinctive profile feature and the content is like following description. (1) The seceder group of Soyang-in showed considerably passive disposition differently from general character of ordinary Soyang group and an appearance attracting the attention is that they demonstrated comparatively higher response at Soeum scale (2) The seceder group of Taieum-in gained low scores in general that informed the passive disposition of the group and the other way of the general property of Taieum group which showed accompanied ascension in Taiyang-Taieum scales they demonstrated sharply declined score at Taiyang scale (3) The seceder group of Soeum-in demonstrated distinctive property similar to the profile feature of Soyang group and it notifies that the passive property of Soeum group was diluted for the most part. According to the above result, the validity of newly revised questionnaire has been proven successfully and the property of seceder groups could be noticed to some degree through the profile analysis on the course of this study. The result of this study is expected to use as a research materials to produce next edition of the questionnaire and it is regarded that further inquisition about the difference between the seceder group and the contrasted group is required for the promotion of the questionnaire as it refered several times in the contents of the main discourse.

• The tire
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• s.96
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• pp.38-40
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• 1981

세계의 자동차용 타이어업계는 "확대"냐 "철퇴"냐 하는 두갈래 길에 놓여있다. 과거 세계적으로 손꼽히던 큰 타이어 메이커로는 미국의 Goodyear, Firestone, Goodrich, Uniroyal ,General의 5대 메이커와 프랑스의 Michelin, 또 영국ㆍ이탈리아의 Dunlop-Pirelli 연합이었다. 그러나 73년과 78년의 2회에 걸친 석유파동을 겪은 후, 각사의 타이어 사업에 대한 계획이 첫째, 끝까지 주요생산품종으로 사업을 계속 확대한다. 둘째, 점차 타이어로부터 철퇴한다는 두 방향으로 흐르고 있다. Radial 타이어의 생산대비지연에다 세계적인 불황이 겹쳐 철퇴하는 방향을 택하고 있는 기업이 나타나고 있으므로 세계적으로 타이어 시장이 재편성 되는 실정에 있다.<편집자주>

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.11
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• pp.2289-2294
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• 2009

In this paper, we proposed a fuzzy controller for racing of a line trace vehicle. Sensor values are computed by statuses of line detecting sensors attached to the line trace vehicle and these sensor values are used for fuzzy inference rules of steering angle control to decide steering angle as output. The decided steering angle is also used for fuzzy inference rules of motor speed control to decide motor speed as output. We experimented and analyzed two proposed methods - one is fuzzy control of steering angle only and the other is fuzzy control of both steering angle and motor speed. In the experiment, we verified that the second proposed method was more efficient in racing speed.

• Journal of Industrial Convergence
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• v.19 no.4
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• pp.103-109
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• 2021

The purpose of this study was to compare the health behaviors of North Korean refugee women according to their health cognition level. The tools were selected through focus group interviews of researchers and respondents to carry out the purpose of the study while being as brief as possible, and to secure content validity by the expert group. Based on this, the health cognition level was divided into three stages and organized into groups, and health behavior was composed of nutrition, exercise, and sleep as three factors to help actual behavior change. For data analysis, one-way ANOVA was used to compare health behaviors according to each health cognition level, and the following conclusions were obtained. First, there was a significant difference in nutrition and sleep of health behavior according to the level of physical health awareness, but there was no significant difference in exercise. Second, there were significant differences in nutrition, exercise, and sleep of health behavior according to psychological health cognitive level. Third, there was a significant difference in nutrition and sleep of health behavior according to social health cognitive level, and there was no significant difference in exercise.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.888-896
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• 2023

When an aircraft is landing, it is expected that the aircraft will follow a specified approach procedure and then land at the airport. However, depending on the airport situation, neighbouring aircraft or the instructions of the air traffic controller, there can be a deviation from the specified approach. Detecting aircraft approach patterns is necessary for traffic flow and flight safety, and this paper suggests clustering techniques to identify aircraft patterns in the approach segment. The Gaussian Mixture Model (GMM), one of the machine learning techniques, is used to cluster the trajectories of aircraft, and ADS-B data from aircraft landing at the Gimhae airport in 2019 are used. The aircraft trajectories are clustered on the plane, and a total of 86 approach trajectory patterns are extracted using the centroid value of each cluster. Considering the correlation between the approach procedure pattern and overshoots, the distribution of overshoots is calculated.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.7
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• pp.506-511
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• 2009

Insect flight is adapted to cope with each circumstance by controlling a variety of the parameters of wing motion in nature. Many researchers have struggled to solve the fundamental concept of insect flight, but it has not been solved yet clearly. In this study, to find the most effective flapping wing dynamics, we conducted to analyze CFD data on fixing some of the optimal parameters of wing motion such as stoke amplitude, flip duration and wing rotation type and then controlled the deviation angle by fabricating wing tip motion. Although all patterns have the similar value of lift coefficient and drag coefficient, pattern A(pear-shape type) indicates the highest lift coefficient and pattern H(pear-shape type) has the lowest lift coefficient among four wing tip motions and three deviation angles. This result suggest that the lift and drag coefficient depends on the angle of attack and the deviation angle combined, and it could be explained by delayed stall and wake capture effect.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.12
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• pp.25-33
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• 2003

A burr has been defined as undesirable projection of material formed as a result of plastic flow from a cutting or shearing operation. It is unavoidable in all kinds of machining operation. As a result, burr makes troubles on manufacturing process due to deburring cost, quality of products and productivity. In this study, the primary interest is about exit burr. The burr formation mechanism in each type of burr is classified. Data bases are developed to predict burr formation result. In the milling operation, we develop an algorithm to analyze the burr formation mechanism by the geometrical analysis on the multi featured workpiece with multi cutting path. The algorithm includes three steps, i. e., the feature identification, the cutting condition identification, and the analysis on exit burr formation. We can predict which portion of workpiece would have the exit burr in advance so that we can manage to find a way to minimize the exit burr formation in an actual cutting. Also, this algorithm can be implemented in a commercial CAM package so that we can simulate the NC code to review the burr formation in advance.

• Korean journal of applied entomology
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• v.36 no.1
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• pp.43-47
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• 1997

This study was carried out in the laboratory to clarify effects of different temperature of Protopulvinaria mangiferae(Green) on development, survivorship and reproduction. Developmental period of the mango shieldscale from crawlers to preoviposition adult decreased as temperature increased. The threshold temperature andthermal constants for the development of one generation were 11.7"C and 1000.0 day-degrees, respectively. At25$^{\circ}$C and 30$^{\circ}$C, survival rate from egg to preoviposition adult were 82% and 6096, respectively. Hatchability ofeggs was more than 99% at both condition. The reproductive period overaged 50 days(2SnC) and 33 days(30$^{\circ}$C). After mature adult began to reporduce, and more than 50% of the crawlers emerged during the firsthalf of their life time. The net reproduction rate per generation(R), mean length of a generation0 and intrinsicrate of natural increase(r, ) were higher at 25$^{\circ}$C than at 30"C, and the values measured at 25$^{\circ}$C were 132.6, 76.2 and 0.064/female/day, respectively.

• Nuclear Engineering and Technology
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• v.27 no.4
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• pp.503-517
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• 1995

A mechanistic model for forced convective transition boiling has been developed to predict transition boiling heat flux realistically. This model is based on a postulated multi­stage boiling process occurring during the passage time of an elongated vapor blanket specified at a critical heat flux condition. Between the departure from nucleate boiling (DNB) and the departure from film boiling (DFB) points, the boiling heat transfer is established through three boiling stages, namely, the macrolayer evaporation and dryout governed by nucleate boiling in a thin liquid film and the unstable film boiling. The total heat transfer rate during the transition boiling is the sum of the heat transfer rates after the DNB weighted by the time fractions of each stage, which are defined as the ratio of each stage duration to the vapor blanket passage time. The model predictions are compared with some available experimental transition boiling data. From these comparisons, it can be seen that the transition boiling heat fluxes including the maximum heat flux and the minimum film boiling heat flux are nil predicted at low qualities/high pressures near 10 bar.