• Korean Journal of Culture and Social Issue
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• v.15 no.2
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• pp.319-338
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• 2009

This study was intended to recognize whether speed desire frustration influences in driving stress. Stress desire frustration is the difference between prefer speed and normal speed. As a result, driver's the prefer speed is higher than the normal speed on 4 road condition(high-way, urban-way, residential-way, rural-way). Also, driver's speed desire frustration caused statistical effect in driving stress on 4 road condition. speed desire frustration effect Driving Stress Scale(DSS) 5 sub-scale factors(progress obstacle, traffic circumstance, accident & regulation, regulation obedience, time pressure). This is that driver who experience much speed desire frustration creates high driving stress. Speed desire frustration analyzed high driver and low driver's Driving Stress Scale(DSS) score and overspeed regulation and traffic accident experience difference. As analysis result, speed desire frustration high driver driving stress high appear. However, difference of overspeed regulation experience or traffic accident experience by speed desire frustration did not appear.

• Proceedings of the KOR-KST Conference
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• 1998.10a
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• pp.382-388
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• 1998

정상 주행 중에 핸들을 급조향하여 요-마크가 생성되면서 일어난 사고들은 핸들 급조향의 원인을 파악해야 대책 수립이 가능하다. 즉 이들 사고의 속도산정과 차량의 운동과정 및 요-마크 생성 이전의 급 조향 당시 위험 요소를 분석해야 대책에 연결될 수 있으나, 아직 정확한 원인규명이 어려운 실정에 있다. 따라서 본 연구에서는 정상 주행중 핸들을 급조향하는 실험을 통하여 요-마크 생성초기 형상의 특성과 선회과정 및 속도 등을 분석하여 교통사고의 원인에 관하여 고찰하였다.

• Korean Journal of Plant Resources
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• v.10 no.4
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• pp.369-374
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• 1997

Many higher fungi of ascomycetes were collected at Mt.Jiri National Park, Pyonsan Peninsula National Park, Mt. Pangtae of Kangwon-do, Mt. Moak Provincial Park of Chollabuk-do and Mt. Manduck near Chonju city from June 1995 to October 1996. Identification of the revealed that Calycellina, Diatrype and Diatrypella were new genera to Korea and Scutellinia umbrarum, S. pseudoumbarum, Dasyscyphus virgineus. Calycellina punctiformis, Xylaria oxyacanthae, Diatrype disciformis, Diatrypella quercina and D. verrucaeformis were newly to Korea.

• Communications of Mathematical Education
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• v.10
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• pp.59-80
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• 2000

수학 학습 부진아의 지도가 효율적으로 이루어지기 위해서는 먼저 원인의 진단이 선행되어야 하고, 이를 바탕으로 적절한 치료 대책이 이루어져야 하는 바, 교사는 수학 학습에서 부진을 야기하는 여러 가지 복합적인 요인에 대한 지식을 갖출 필요가 있다. 학생들이 수학적 이론의 구조 속에 싸여 있을 때, 수학적 개념과 원리를 잘 이해하는 것처럼, 교사는 수학 학습 부진의 요인에 대한 이론의 구조 속에서 학생들의 행동을 투사함으로써 그들의 행동을 이해하게 되고 진단과 치료가 잘 이루어질 것이다. 이와 같은 관점에서 본 연구는 수학 학습 부진의 요인을 크게 개인적 측면과 환경적 측면으로 나누고, 개인적 측면에서는 인지적 요인, 심동적 요인, 정서적 요인을, 환경적 측면에서는 사회적 요인, 교육적 요인에 대해 고찰한다. 그리고 이들 요인에 대한 정확한 처방을 하기에는 어려움이 많지만, 최선의 교육적 치료 방법을 논의해 보고자 한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.965-966
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• 2014

The range and velocity ambiguities depending on the selected PRF are the serious problems in ultrasonic measurement. Therefore, the PRF selection method in the generation of waveform are analyzed. Also, the effects on measurements are discussed.

• Journal of Convergence for Information Technology
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• v.12 no.2
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• pp.142-148
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• 2022

In this paper, the weight reduction design of the yaw gearbox for wind turbine was performed through the finite element analysis method, and the stability was checked by performing the critical speed analysis. The weight reduction product can improve engine efficiency, save parts materials, and earn economic benefits. The yaw gearbox is lightweighted with the goal of achieving a safety rate of 1.3 or higher for wind turbine as indicated by IEC61400-1. In order to reduce the weight of the carrier, a topology optimization method was performed. The safety factor was verified by performing finite element analysis on the carrier. In addition, the housing and carrier were modeled using the finite element method, and the gear train was modeled using MASTA. For the yaw gearbox, the housing and carrier FE model and the gear train model were connected by the partial structural synthesis method to perform the rotational vibration analysis. Vibration excitation sources are mass unbalance and gear mesh frrequemcy, and as a result of the critical speed analysis, it was found that there was no resonance within the operating speed range.

• 도로교통
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• s.97
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• pp.71-83
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• 2004

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.8 s.179
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• pp.1899-1909
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• 2000

This paper proposes a new $H_{\infty}$ yaw moment control scheme using brake torque switching for improving vehicle performance and stability especially in high speed driving. In the scheme, one wheel is selected, depending on the vehicle states, at which a brake torque for control is applied. Steering angles are modeled as a disturbance to the system and the $H_{\infty}$ controller is designed to minimize the difference between the performance of the vehicle and that of the desired model. Its performance robustness as well as stability robustness to system parameter variations is assured through ${\mu}$-analysis. Various simulations with a nonlinear 8-DOF vehicle model show that proposed controller enhances the vehicle performance and stability under disturbances and parameter variations as well as under the normal driving condition.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.4
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• pp.361-370
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• 2015

There will inevitably be errors and uncertainties in tire yaw mark related critical speed formula, which is derived merely from the relationship between the centrifugal force and the friction force acting on the point-mass vehicle. Constructing and measuring yaw marks through appropriate simulation works have made it possible to perform uncertainty analysis in calculation of critical speeds under variation of variety of conditions and parameters while existing yaw mark experimental tests have not performed properly. This paper does not present only the critical speed analysis results for parametric sensitivity and uncertainty of chord and middle ordinate, coefficient of friction and road grade, but also modeling uncertainty such as variation of braking level during turning and vehicle size. The yaw mark analysis methods and results may be now applied in practice of traffic accident investigation.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.269-273
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• 2015

처음 에디슨 경진대회를 준비할 때 업로드 되어 있는 다양한 프로그램을 보면서 어떤 주제를 선정할 지 고민을 하던 중, 눈에 들어온 프로그램은 서울대학교에서 제작한 Co-rotational Plane beam-Dynamic tip load이란 프로그램이었다. 위 프로그램은 한쪽 단이 고정된 외팔보(cantilever beam)의 끝단에 하중을 시간에 관련된 함수(sin, cos)로 주어 각 절점에서의 변위(X, Y), 속도 그리고 가속도를 알려주는 프로그램이다. 우리는 이 프로그램을 이용해서 외팔보 끝단의 진동 형태와 주기가 어떤 요인(단면의 모양, 재료의 성질, 가하는 하중의 진동수 등)에 의해서 변하는지 분석할 수 있었다. 거기서 더 나아가 하중을 실제 지진상황에서의 크기와 유사하게 주고 위 프로그램에서의 보의 거동(진동 주기, 진동 변위 등)을 건물의 거동이라 가정했을 때 면진 주기를 얼마로 설정해야하는지도 알 수 있었다.