• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.1
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• pp.82-96
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• 2024

While analyzing traffic flow, speed, traffic volume, and density are important macroscopic indicators, and acceleration and spacing are the important microscopic indicators. The speed and traffic volume can be collected with the currently installed traffic information collection devices. However, acceleration and spacing data are necessary for safety and autonomous driving but cannot be collected using the current traffic information collection devices. 'You Look Only Once'(YOLO), an object recognition technique, has excellent accuracy and real-time performance and is used in various fields, including the transportation field. In this study, to measure acceleration and spacing using YOLO, we developed a model that measures acceleration and spacing through changes in vehicle speed at each interval and the differences in the travel time between vehicles by setting the measurement intervals closely. It was confirmed that the range of acceleration and spacing is different depending on the traffic characteristics of each point, and a comparative analysis was performed according to the reference distance and screen angle to secure the measurement rate. The measurement interval was 20m, and the closer the angle was to a right angle, the higher the measurement rate. These results will contribute to the analysis of safety by intersection and the domestic vehicle behavior model.

• Journal of The Korean Association For Science Education
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• v.34 no.5
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• pp.437-447
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• 2014

Learning progressions (LP), which describe how students may develop more sophisticated understanding over a defined period of time, can inform the design of instructional materials and assessment by providing a coherent, systematic measure of what can be regarded as "level appropriate." We developed LPs for the nature of matter for grades K-16. In order to empirically test Korean students, we revised one of the constructs and associated assessment items based on Korean National Science Standards. The assessment was administered to 124 Korean secondary students to measure their knowledge and submicroscopic representations, and to assign them to a level of learning progression for the particle nature of matter. We characterized the level of students' understanding and models of the particle nature of matter, and described how students interpret various representations of atoms and molecules to explain scientific phenomena. The results revealed that students have difficulties in understanding the relationship between the macroscopic and molecular levels of phenomena, even in high school science. Their difficulties may be attributed to a limited understanding of scientific modeling, a lack of understanding of the models used to represent the particle nature of matter, or limited understanding of the structure of matter. This work will inform assessment and curriculum materials development related to the fundamental relationship between macroscopic, observed phenomena and the behavior of atoms and molecules, and can be used to create individualized learning environments. In addition, the results contribute to scientific research literature on learning progressions on the nature of matter.

• Journal of the Mineralogical Society of Korea
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• v.28 no.1
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• pp.61-69
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• 2015

While the macroscopic properties and eruption style of basaltic and phonolitic melts are different, the microscopic origins including atomic structures are not well understood. Here we report the atomic structure differences of glass in diopside-anorthite eutectic composition (basaltic glass) and phonolitic glass using high-resolution 1D and 2D solid-state Nuclear Magnetic Resonance (NMR). The $^{27}Al$ MAS NMR spectra for basaltic glass and phonolitic glass show that the full width at half maximum (FWHM) of Al for basaltic glass is about twice than phonolitic glass, suggesting the topological disorder of basaltic magma is larger than that of phonolitic magma. The $^{27}Al$ 3QMAS NMR spectra for basaltic glass and phonolite glass show much improved resolution than the 1D MAS NMR, resolving Al and Al. Approximately 3.3% of Al is observed for basaltic glass, demonstrating the configurational disorder of basaltic magma is larger than phonolitic magma. This result confirms that the topological disorder of Al in basaltic glass is larger than that of phonolitic glass. The observed structural differences between basaltic glass and phonolitic glass can provide an atomistic origin for change of the macroscopic properties with composition including viscosity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3176-3183
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• 2010

A multi-scale fatigue life prediction methodology of composite pressure vessels subjected to multi-axial loading has been proposed in this paper. The multi-scale approach starts from the constituents, fiber, matrix and interface, leading to predict behavior of ply, laminates and eventually the composite structures. The multi-scale fatigue life prediction methodology is composed of two steps: macro stress analysis and micro mechanics of failure based on fatigue analysis. In the macro stress analysis, multi-axial fatigue loading acting at laminate is determined from finite element analysis of composite pressure vessel, and ply stresses are computed using a classical laminate theory. The micro stresses are calculated in each constituent from ply stresses using a micromechanical model. Three methods are employed in predicting fatigue life of each constituent, i.e. a maximum stress method for fiber, an equivalent stress method for multi-axially loaded matrix, and a critical plane method for the interface. A modified Goodman diagram is used to take into account the generic mean stresses. Damages from each loading cycle are accumulated using Miner's rule. Monte Carlo simulation has been performed to predict the overall fatigue life of a composite pressure vessel considering statistical distribution of material properties of each constituent, fiber volume fraction and manufacturing winding angle.

• Journal of Cadastre & Land InformatiX
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• v.47 no.1
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• pp.127-142
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• 2017

The purpose of this study is to examine the status of urbanization of Namyangju-Si from 2001 till 2008, analyze the correlation of the change of surrounding land use according to the change of accessibility and analyze the correlation of the change of land use. Based on the result from correlation analysis, I simulated from the view point of interactions between agents of land use and transportation accessibility by using MAS. I tried to forecast, based on space, the change of surrounding land use caused by the change of accessibility. I conducted landscape analysis by using a land registration map. Also, I conducted GIS analysis statistical analysis simulation analysis of traffic data, land use data in order to analyze the correlation of the change of surrounding land use according to the change of accessibility. I could find out a certain pattern that new roads and railroads causes the within 500m adjacent land to change into urban land use, which led me to construct a system through which land use changing phenomenon can be expected according to the change of accessibility. It is expected that it can make the best use of selecting the location where new transportation facilities are constructed.

• Proceedings of the SOHE Conference
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• 1999.10a
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• pp.85-101
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• 1999

새천년에 대한 미래를 생각해보면 우리에게 회망과 동시에 웬지 모를 불안올 주기도 한다. 발전지향적으로 살아 온 우리 인간의 지혜로 말미암아 현대에 살고 있는 우리는 과 거 우리 조상 어느 시대 못지 않게 첨단 과학 기술의 혜택으로 물질적 풍요와 함께 사 상적으로도 신분계급이나 남녀문제나 이데올로기의 극심한 차별이 사라져가는 그야말 로 자유스러운 생활올 맛보고 있다. 그러나 한편으로는 이러한 혜택과 이익을 얻는 대 신 지나친 물질의 생산과 사용의 과다는 우리 환경을 파괴하고 나아가 정신적으로도 물질의 지배를 받게 되는 즉, 물질의 소유와 사용에 따른 삶과 사람의 평가가 횡행하 는 기이한 구조에 우리 자신도 모르는 사이에 말려 들어가 피폐된 정신환경의 진행을 우려하지 않올 수 없다. 누구든지 공감하는 이러한 부분이 아마도 다가올 21세기에 대 한 불안이 아닐까 생각한다. 우리의 주거생활도 반세기도 채 안되는 이 시점에 그동안 놀라운 변모를 거듭하여 비교적 선진국과 가까운 수준에 육박하고 있다. 그렇다면 지금 이 시점에서 다가올 주 생활에 대한 이야기는 잘못되어지는 불안을 막고 더 멋지고 쾌적한 주거환경올 창출하 여 주거의 질을 높히기 위한 선도적 쟁점이 되어야 할 것이다. 이러한 의미에서 본고 에서는 새천년의 주거생활문화에 대한 주제를 거시적이고 개념적인 정책적 내용보다는 생활과학의 한 맥락에서 미시적이고 구체적이며 실천지향적인 뜩변에서 나아가야 할 쟁점이 무엇인지를 함께 생각해 보고자 하며 학술 이론적 내용보다는 평이한 사례를 중심으로 함께 생각해 보고자 한다. 밝혀졌다. 그러나, 생산계획시스템에서 1주 간격으로 계획오더를 이송할 때는 Order Release 방법을 적용하여 작업현장에서의 평균 리드타임과 리드타임의 변동, 공정중재고가 줄어드는 결과를 보였고, 가동률 수준이 높을수록 ORR 방법간의 차이가 크게 나타났다. 그리고 부하평준화 기능은 Order Release 정책의 유효성에 별 영향을 주지 않는 것으로 나타났다. 결론적으로, Order Release 방법은 우선순위규칙간의 성능차이를 줄이거나, 대체할 수 통제 기법이라기보다는 우선순위규칙을 보완하여 공정중재고와 작업현장에서의 리드타임, 리드타임의 편차를 줄여주는 역할을 한다고 볼 수 있다. 그리고, 계획시스템이 존재하여 계획오더가 일정기간간격으로 이송되는 환경에서 특히 유용하다는 결론을 얻었다. 알 수 있었다. 것인데, 제조업에서의 심각한 고비용, 저효율 문제 를 해결하기 위해 필수적으로 도입해야만 하는 실정이다. 또한 소비자의 다양한 요구로 인 하여 제품의 종류와 사양면에서 심한 변동을 보이는 시장 수요에, 신속한 정보처리로 대응 하는데도 크게 기여하고 있다. 이에 본 연구에서는, 자동차 Job Shop의 동기화 생산방식을 지원하는 동기화 생산시스템의 구축 모델을 제시하고자 한다.과로 여겨지며, 또한 혈청중의 ALT, ALP 및 LDH활성을 유의성있게 감소시키므로서 감잎 phenolic compounds가 에탄올에 의한 간세포 손상에 대한 해독 및 보호작용이 있는 것으로 사료된다.반적으로 홍삼 제조시 내공의 발생은 제조공정에서 나타나는 경우가 많으며, 내백의 경

• 한국노년학
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• v.29 no.3
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• pp.805-822
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• 2009

This study aims to investigate the mental health level of the elderly people living alone and examine the difference in mental health level by socio-demographic factors and analyze the factors impacting on mental health level. The study subjects were 131 elderly people living alone who lived in "G" city. Symptom Check List-90-Revision(SCL-90-R) was used to measure mental health level. The results of this study were as follows. First, the study subjects' mental health level(3.53, 5 rating scale) was very severe and this means the mental health level of elderly people living alone is more severe than the mental health level of general elderly people. The study subjects showed depression symptom most seriously and also had severe somatization symptom. Second, there was significant difference in mental health level by gender and education level among socio-demographic factors. Third, in the final regression model, statistically significant factors impacting on the mental health level of the elderly people living alone were life satisfaction, ADL, IADL, welfare service support, informal support, contact frequency with children, duration of living alone, subjective state of economy. And comprehensive(macro and micro) implications were recommended.

• Journal of Korea Port Economic Association
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• v.40 no.1
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• pp.87-118
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• 2024

Coastal ports play an essential role in developing a country and a city. Port efficiency is an important factor affecting port trade, and the importance of port efficiency for port performance has been recognized in previous literature. DEA (Data Envelopment Analysis) and SFA (Stochastic Frontier Analysis) are widely used in this field of research. However, these two methods are limited in selecting input and output variables. In addition, the literature studies on Chinese coastal ports mainly focus on the study of port clusters in local areas, which lacks a holistic approach and generally lacks up-to-date data. Therefore, to fill the gap in this area of research, this paper introduces a model combining principal component analysis and data envelopment analysis to analyze the operational efficiency of the top 17 coastal ports in China in terms of throughput based on the most recent data available in 2021. This paper identifies container throughput as the output variable, and 13 second indicators are selected as input variables from four primary indicators: land, capital, labor, and infrastructure. Four principal components were selected from 13 second indicators using PCA.After that, DEA (BBC) and DEA (CCR) were used to analyze the 17 ports, among which five were Shanghai, Ningbo-Zhoushan, Guangzhou, Xiamen, and Dongguan, respectively, DEA efficient, and the remaining 12 ports were non-DEA efficient. Finally, improvement directions for each port are derived, and brief suggestions are made. This paper provides some reference value for developing and constructing coastal ports in China.