• 한국과학교육학회지
• /
• 제29권8호
• /
• pp.910-922
• /
• 2009

본 연구에서는 물리를 전공하지 않은 중학교 과학 교사들의 '힘과 운동' 영역의 교과내용지식에 대한 전문성의 정도를 서술형 응답 분석 및 심층 면담의 방법을 통해서 조사하였다. 조사 대상으로는 화학, 생물, 지구과학을 전공한 중학교 과학 교사 9명을 선정하였으며, 이들을 대상으로 물리 개념 조사 도구를 투입하여 이들의 서술형 응답 내용의 분석 및 심층 면담 내용의 분석 결과로부터 이들의 '힘과 운동' 내용 지식 영역에서의 전문성을 분석하여 물리를 전공하지 않은 중학교 과학 교사들의 전문성을 유추해 보았다. 연구의 결과, 연구 대상 교사들의 '힘과 운동' 영역개념에 대한 정답률이 높지 않고 일부 교사는 오개념을 가지고 있음을 볼 때, 중학교 수준의 물리 내용 지식, 적어도 힘과 운동 영역의 물리 영역의 전문성이 높다고 보기 어렵고, 따라서 물리 개념을 정확히 설명하는 데 어려움을 겪을 수 있다고 생각되며, 상황이 달라졌을 때 물리 개념을 일관성 있게 적용하지 못한 다든지, 공식을 단순히 적용하여 해결함으로써 문제해결에 대한 정성적인 이해가 부족함을 보임을 볼 때, 학생들에게 물리 개념의 적용 및 심화 적용 능력을 지도하는 데 어려움이 있음을 유추할 수 있다.

• 대한수학교육학회지:수학교육학연구
• /
• 제14권3호
• /
• pp.267-281
• /
• 2004

방정식의 활용 문제로 다루어지는 문장제는 학생들의 흥미를 유도하고 수학의 유용성을 보여줄 수 있는 것이지만, 학생들이 해결하기에는 여러 어려움이 있다. 본 연구는 학생들이 수학 문장제를 해결하는데 영향을 줄 수 있는 요인들을 언어적 측면과 인지적 측면에서 조사하였다. 언어적 요인에는 텍스트 기반, 실세계, 상황 모델이 있었는데, 학생들은 문장의 텍스트 기반에서 방정식의 상황 모델로 해석하는 것을 어렵게 생각하고 있었으며, 상황 모델에서 학생들은 많은 오류를 보였다. 인지적 측면에서는 방정식을 세우는 스키마와 해결 전략, 식의 복잡성 수준을 조사하였는데, 방정식을 세울 때 학생들은 복잡성 수준을 고려하기보다는 교사의 지도 내용에 따라 전략을 선택하는 경향이 있었다. 그리고 설탕의 양이나 농도, 설탕물의 양을 혼동하는 경향이 강했다. 본 연구의 결과를 통해 문장제에서 학생들에게 제시되는 문제가 해결하기에 얼마나 복잡한지, 학생들이 주로 어떤 전략을 선택하는지, 방정식의 문제 유형별로 발생하는 오류에 대해 알 수 있었다.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2005년도 학술발표논문집
• /
• pp.215-218
• /
• 2005

This study was carried out to find problems of the farmland according to the large scale land consolidation projects. Field ramp have problems such as steep slope, narrow width and the difficulty of entering into field and exiting from it. In case of the even ratio of the paddy plot, It showed that the difference of the maximum average level were 8.4cm for the general plots($0.3{\sim}0.4ha$), 12.6cm for the large scale plots($0.8{\sim}1.0ha$), and the level of outlet part was higher than the level of inlet part in some plots. Also, most of presently using inlets are closed and opened manually. It showed that farmers had difficult in the operating of the inlets or the outlets. So it is required the development of the suitable inlets and the suitable outlets.

• 센서학회지
• /
• 제31권1호
• /
• pp.36-40
• /
• 2022

High-power devices, such as LEDs and radars, inevitably generate a large amount of heat, which is the main cause of shortening lifespan, deterioration in performance, and failure of electronic devices. The embedded IC process can be a solution; however, when applied to large-area substrates (larger than 8 in), there is a limit owing to the difficulty in the process after wafer thinning. In this study, an 8-in wafer-level high-power electronic package based on the embedded IC process was implemented with temporary bonding and debonding technology using double-sided thermal release tape. Good heat-dissipation characteristics were demonstrated both theoretically and experimentally. These findings will advance the commercialization of high-power electronic packaging.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.171.2-171
• /
• 2001

This paper presents a force control of a arm of walking training robot. The current gait training apparatus in hospital are ineffective for the difficulty in keeping constant unloading level and constraining patients to walk freely. The proposed walking training robot is designed to unload body weight effectively during walking. The walking training robot consists of unloading manipulator and mobile platform. The manipulator driven with a electro-mechanical linear mechanism unloads body weight in various level. The mobile platform is wheel type, which allows to patients unconstrained walking. Unloading system with electro-mechanical linear mechanism has been developed, which has advantages such as low noise level, light weight, low manufacturing cost and low power consumption. A system model for the manipulator ...

• Journal of Power Electronics
• /
• 제16권2호
• /
• pp.473-479
• /
• 2016

In this paper, the PSC PWM method is chosen as the optimal modulation method for a 20MW VSC HVDC, with consideration of the harmonic distortion of the output voltage, the switching frequency, and the control implementation difficulty. In addition, a new PSC PWM method is proposed in order to achieve an easy application and to solve the redundant control problems encountered in the previous PSC PWM method. To verify the proposed PSC PWM method, PSCAD/EMTDC simulations for an 11-level MMC RTDS HILS test and an 11-level MMC prototype converter test were performed. As can be seen from the results of these tests, the proposed PSC PWM method shows good results in an 11-level MMC with redundant sub-modules.

• 한국지구과학회지
• /
• 제41권4호
• /
• pp.405-414
• /
• 2020

In this study, we analyzed the development of high school students' argumentation through their writings on socio-scientific Issues (SSI) related to the Climate Change Unit in the Earth Science I curriculum. Pre- and post-writing assignments on the two main causes of global warming were analyzed and compared. In addition, an in-depth interview of the focus group was conducted with 7 students who showed a distinct change in the level of argumentation. According to the results, 16 of 52 students remained at the same argumentation level in pre- and post-writing assignments, and students remaining at Level 2 among five levels had difficulty in understanding the Toulmin's argument pattern (TAP) structure. Using the TAP structure, 29 of 52 students demonstrated increased argumentation levels in the post-writing assignments. The conclusions include that writing lessons on SSI using the TAP in Earth science classes can improve the level of high school students' argumentative writing, and that the level of students' argumentation can develop with the elaboration of their level of falsification. Also, it is suggested that the science curriculum should increase students' science writing competencies by specifying science writing as one of the goals.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
• /
• pp.31-35
• /
• 2003

High-Flowability Concrete has many advanced properties and been focused on their workability. Because of the difficulty in understanding of the quality of High-Flowablity Concrete just using slump properties, many studies have been carried out rheological properties influenced on concrete fluidity. In this paper, for the purpose of expecting some level of rheological properties, the change of rheological properties of High-Flowability Concrete with dosages and types of superplasticizer, and various addition amounts addictives were investigated.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
• /
• pp.194-196
• /
• 2013

Recently, It is a fact that the percentage of female field managers has increased in the construction industry. Therefore, this study investigated the percentage of female construction site managers by conducting a survey of current male and female construction site managers and then analyzed the workload, work difficulty, work importance and performance level of female employees in charge of public affairs, which is the most common tasks.

• 한국경영과학회지
• /
• 제9권2호
• /
• pp.46-55
• /
• 1984

The purpose of this parer is to provide a survey of the state of the art of routing methods in store-and-forward computer networks. The survey is carried out in line with a new taxonomy： heuristic methods, user-optimization methods, and system-optimization methods. This taxonomy on routing algorithms is based on two viewpoints： the level of optimization and the relative difficulty for the implementation in real computer networks. Some actual methods implemented in real computer networks are surveyed as well as the theoretical studies in the literature. This paper concludes with some points in need of further researches.