• 대한안전경영과학회지
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• 제19권4호
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• pp.231-240
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• 2017

The paper explores the relationship among the personnel characters, organizational formalization and organizational commitment in Korean firms in Shandong province of China. In this paper, the employee's personnel characters include the sexual, job, college graduate, collectivism(value attitude), Power distance(value attitude). The results of anaysis shows that College gratuate have negative effects on the organizational commitment, and the collectivism have positive effection on the affective commitment, the perception of organizational formalization have positive effects on the affective commitment. And, the perception of organizational formalization have moderlate effects among the job, college gratuate, collectivism, power distance with organizational commitment. Based on the these results, the paper described the theoretical and practical implications.

• 한국연소학회지
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• 제13권4호
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• pp.26-36
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• 2008

Experimental study is conducted to identify the existence of a shrinking flame disk and to clarify its flame characteristics through the inspection of critical mole fraction at flame extinction and edge flame oscillation at low strain rate flames. Experiments are made as varying global strain rate, velocity ratio, and burner distance. The transition from a shrinking flame disk to a flame hole is verified through gradient measurements of maximum flame temperature. The evidence of edge flame oscillation in flame disk is also provided through numerical simulation in microgravity. It is found at low strain rate flame disks in normal gravity that buoyancy effects are importantly contributing to lateral heat loss to burner rim, and is proven through critical mole fraction at flame extinction, edge flame oscillation, and measurements of flame temperature gradient along flame disk surface.

• 한국정보처리학회논문지
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• 제7권10호
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• pp.3280-3289
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• 2000

본 논문에서는 볼륨데이터와 전역적 형태정보를 이용하여 볼륨렌더링의 질적측면과 속도측면에서 개선할 수 있는 선택적 볼륨렌더링방법을 제안한다. 선택적 볼륨렌더링방법은 관심부위를 구성하는 외곽선으로부터 최소거리를 결정하는 거리변환을 통하여 거리변환볼륨을 생성하고 이를 렌더링하는 방법으로 형태정보를 이용함으로써 서로 다른 객체들간에 비슷한 명암도로 인해 동일 객체로 인식되는 것을 방지하고, 복잡한 형태를 효과적으로 나타낼 수 있다. 실험결과로는 EBCT 심장데이터에 선택적 볼륨렌더링방법을 적용하여 좌심실, 우심실 렌더링 결과영상과 함께 보간법에 따른 선택적 샘플링 방법 적용결과를 제시한다. 본 제안방법은 볼륨데이터로부터 얻은 형태정보로부터 관심객체 표면을 정확하고 빠르게 가시화할 수 있다.

• Geomechanics and Engineering
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• 제37권4호
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• pp.395-418
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• 2024

The epicentral region of earthquakes is typically where liquefaction-related damage takes place. To determine the maximum distance, such as maximum epicentral distance (R_e), maximum fault distance (R_f), or maximum hypocentral distance (R_h), at which an earthquake can inflict damage, given its magnitude, this study, using a recently updated global liquefaction database, multiple ML models are built to predict the limiting distances (R_e, R_f, or R_h) required for an earthquake of a given magnitude to cause damage. Four machine learning models LSTM (Long Short-Term Memory), BiLSTM (Bidirectional Long Short-Term Memory), CNN (Convolutional Neural Network), and XGB (Extreme Gradient Boosting) are developed using the Python programming language. All four proposed ML models performed better than empirical models for limiting distance assessment. Among these models, the XGB model outperformed all the models. In order to determine how well the suggested models can predict limiting distances, a number of statistical parameters have been studied. To compare the accuracy of the proposed models, rank analysis, error matrix, and Taylor diagram have been developed. The ML models proposed in this paper are more robust than other current models and may be used to assess the minimal energy of a liquefaction disaster caused by an earthquake or to estimate the maximum distance of a liquefied site provided an earthquake in rapid disaster mapping.

• 실천공학교육논문지
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• 제16권4호
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• pp.577-585
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• 2024

This study analyzed the relationship between GPS-based physical activity patterns and mental health using Kaggle Student Life data. Data were collected over a 10-week period from 48 students at Dartmouth College through Android smartphones and included GPS, dark, and phone lock data, and measures such as the Patient Health Questionnaire-9 (PHQ-9), Loneliness Scale, the Positive and Negative Affect Schedule (PANAS), and Perceived Stress Scale. Using latitude and longitude data obtained from GPS measurements, various physical activity indicators were calculated, including the total distance traveled, average distance traveled, average distance traveled in the morning, average distance traveled in the afternoon, average distance traveled in the evening, and average distance traveled in the middle of the night. Pearson's correlation analysis was performed to explore the relationship between GPS-based physical activity patterns and mental health. The study results indicated a significant negative correlation between the average distance traveled in the afternoon and PHQ-9 scores. Results indicated that the higher the afternoon activity, the lower the depressive symptoms. There was a positive correlation be-tween the PANAS-Pos score and the average distance traveled in the evening, indicating that positive emotions tended to increase as evening activities increased. This finding suggests a relationship between physical activity at specific times and mental health.

• 한국지역지리학회지
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• 제10권2호
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• pp.356-370
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• 2004

인터넷의 확산과 함께 글로벌 커뮤니케이션을 가로막았던 경제적, 지리적 장벽은 정차 제거되고 있는 상황에서 인터넷을 이용한 국가간 정보교환에 대한 연구, 그리고 정보교환과 지리적 거리와의 상관성 등에 대한 연구는 충분히 이루어 지지 않은 형편이다. 본 연의 목적은 인터넷 상에서 각 국가가 지닌 사이버상의 디지털 위치에 대한 현황과 함께, 이것이 국가간 지리적 경계와 어떤 연관성이 있는가를 검토하는 것이다. 연구 결과에 따르면, 미국이 사이버 공간에서 가장 중심적인(central) 위치를 차지하는 것으로 나타났다. 다음으로 영국, 독일, 호주, 이태리, 프랑스, 캐나다, 일본, 중국이 준중심적인(semi-central) 국가들이었다. 주변적인(peripheral) 국가들은 우루과이, 룩셈부르그, 아람에밀레이트 등으로 나타났다. 둘째로 사이버 공간의 국가별 디지털 위치와 지리적 거리는 통계적으로 유의미한(significant) 상환관계를 보이지 않았다.

• Spatial Information Research
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• 제14권4호
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• pp.433-449
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• 2006

본 연구는 인간이 인지거리를 지도화 함에 있어, 성별, 연령, 학년, 수학기간 등의 개인적인 요인과 거리 추정에 사용된 기준점의 상대적인 위치가 거리 추정에 어떤 영향을 주는 지를 위치정보 시스템을 이용한 현장 실험을 통해 파악하고자 하였다. 연구 방법으로는, 미국 캔자스대학교에 재학 중인 학부생과 대학원생을 대상으로 캠퍼스 방문을 통한 설문조사를 실시하였다. 자료분석 결과, 여학생 그룹의 거리추정 정확도가 인종이나 학년에 관계없이 남학생 그룹에 비해 높았으며, 전체적으로 학년과 연령이 높아지고 수학기간이 길어짐에 따라 거리 추정 정확도의 분산정도가 감소하는 것으로 나타났다. 인지거리 지도화를 위해 제시된 2개 기준점에 가까이 위치한 건물 일수록 거리 추정의 정확도가 높았으며, 설문조사 지점이 기준점에 가까울수록 거리 추정의 오차가 감소하였다. 상관관계 분석 결과, 남학생 그룹의 거리추정 오차값이 여학생 그룹에 비해 건물-기준점 간 거리, 그리고 피실험자-기준점 간 거리와 더 강한 상관관계를 가진 것으로 보아, 남학생이 여학생에 비해 기준점에 근거한 공간적 축척을 더 면밀하게 이용하는 것으로 판단된다.

• 제어로봇시스템학회논문지
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• 제15권7호
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• pp.734-741
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• 2009

A new localization algorithm is proposed for a fast moving mobile robot, which utilizes only one beacon and the global features of the differential-driving mobile robot. It takes a relatively long time to localize a mobile robot with active beacon sensors since the distance to the beacon is measured by the traveling time of the ultrasonic signal. When the mobile robot is moving slowly the measurement time does not yield a high error. At a higher mobile robot speed, however, the localization error becomes too large to locate the mobile robot. Therefore, in high-speed mobile robot operations, instead of using two or more active beacons for localization, only one active beacon and the global features of the mobile robot are used to localize the mobile robot in this research. The two global features are the radius and center of the rotational motion for the differential-driving mobile robot which generally describe motion of the mobile robot and are used for the trace prediction of the mobile robot. In high speed operations the localizer finds an intersection point of this predicted trace and a circle which is centered at the beacon and has the radius of the distance between the mobile robot and the beacon. This new approach resolves the large localization error caused by the high speed of the mobile robot. The performance of the new localization algorithm has been verified through the experiments with a high-speed mobile robot.

• 한국항행학회논문지
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• 제26권6호
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• pp.434-440
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• 2022

ICAO (international civil aviation organization)에서는 전략적인 의사결정과 항공교통관리 평가를 위해 세계항행계획인 GANP (global air navigation plan) 수행을 체약국에게 권고하였다. 본 연구에서는 항공교통관리 평가를 위해 제시된 KPI (key performance indicator) 05 실제 항로 연장에서 항로거리를 구하는 새로운 방법을 제안하였다. 이를 위해 한 달간의 항적 데이터를 수집하고 ICAO에서 제시한 방법과 본 저자가 제시하는 방법으로 각각 항로거리를 산출하였다. ICAO 방법은 반경 40 NM 원형에 대한 원의 방정식과 항적 데이터 내 원에 근접한 내·외부 지점에 대한 직선의 방정식을 통하여 교점을 추정하여야 하고, 네 가지의 비행거리를 계산하여 항로거리를 산출한다. 본 연구에서 제시한 방법은 교점을 추정하지 않고 두 가지의 비행거리를 계산하여 항로거리를 산출한다. 두 방법의 오차를 확인하기 위해 회귀모형 성능평가지표인 RMSE (root mean square error)와 결정계수 R² 를 사용하였다.

• Journal of Korea Trade
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• 제24권8호
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• pp.133-152
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• 2020

Purpose - The purpose of this study is to analyze the determinants of commodity trade in Korea and China and to examine the implications of China's GVC shift from export to domestic market on its impact on Korea's trade. Design/methodology - This study selected 30 major trading partner countries. The dependent variable is the trade volume, and the independent variables are general economic factors such as gross domestic product (GDP), GDP per capita, distance, and FTA. Findings - The trade pattern of Korea's commodities shows that GDP has a positive relationship with trade, import, and export. Distance has a significant negative relationship with total trade, import, and export. FTA is significant for import but it is not significant for total trade and export. The trade pattern of China's commodities shows that GDP has a significant positive relationship with total trade, import, and export. Distance has a negative relationship with trade, import, and export. GDP per capita is not significant for total trade and import, but it is significant for export. FTA is significant for total trade and export, but it is not significant for import. Originality/value - Existing papers were studied mainly in certain industrial sectors such as agriculture, manufacturing, automobile industry and steel industry. This paper attempts to collects vast amounts of data about the 30 countries of Korea and China respectively and analyzes by Random Effect Model dividing the goods (0 to 9) in units of STIC (Rev. 4). The major contribution is that the decision factors affecting commodity trade can be analyzed in SITC units (0-9) to obtain analysis results that are subdivided by product group and organized by product.