• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.5
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• pp.617-623
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• 2010

In this research an LMI based mixed $H_2/H_{\infty}$ controller for a Wheeled Inverted Pendulum is designed and a numerical simulation of that is carried out. The Wheeled Inverted Pendulum is a kind of an inverted pendulum that has two equivalent points. To keep that the naturally unstable equivalent point, a controller should control the wheels persistently. Dynamic equations of the Wheeled Inverted Pendulum are derived with considering inclined road that is one of the representative road conditions. A Linear Matrix Inequality method is used to construct a controller that is able to stabilize the Wheeled Inverted Pendulum with considering the inclined road condition aggressively. Various numerical simulations show that the LMI based controller is doing well on not only flat road but also inclined road condition.

• Journal of the Korean School Mathematics Society
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• v.25 no.4
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• pp.353-374
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• 2022

The study investigated students' instrumentalization levels and computer programming self-efficacy in mathematics classrooms while using Scratches, to understand the properties of equality. 32 of 7th-grade students from D middle school in Gyeonggi-do participated in the program consisting of 7 lesson units. To investigate individual students' levels of instrumentalization, each worksheet they worked on using Scratches was saved into computers after each lesson. Questionnaires measured self-efficacy regarding computer programming at the study's beginning and the end. The level of students' instrumentalization was revealed to be variously from level 0 to 4. In the beginning, 9% of students corresponded to level 3 or 4, but more than 80% of students reached level 3 or above at the end. In addition, computer programing self-efficacy was improved significantly.

• Communications of Mathematical Education
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• v.24 no.3
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• pp.543-562
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• 2010

The purpose of this thesis is to analyze the error happening in the process of solving the simultaneous inequality with two unknown qualities and to propose the correct teaching method. We first introduce a problem about the simultaneous inequality with two unknown qualities. And we will see the solution which a student offers. Finally we propose the correct teaching method by analyzing the error happening in the process of solving the simultaneous inequality with two unknown qualities. The cause of the error are a wrong conception which started with the process of solving the simultaneous equality with two unknown qualities and an insufficient curriculum in connection with the simultaneous inequality with two unknown qualities. Especially we can find out the problem that the students don't look the interrelation between two valuables when they solve the simultaneous inequality with two unknown qualities. Therefore we insist that we must teach students looking the interrelation between two valuables when they solve the simultaneous inequality with two unknown qualities.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.326-331
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• 2018

Crop growth models are useful tools for understanding and integrating knowledge about crop growth. Models for predicting plant height, net photosynthesis rate, and plant growth of quinoa (Chenopodium quinoa Willd.) as a leafy vegetable in a closed-type plant factory system were developed using empirical model equations such as linear, quadratic, non-rectangular hyperbola, and expolinear equations. Plant growth and yield were measured at 5-day intervals after transplanting. Photosynthesis and growth curve models were calculated. Linear and curve relationships were obtained between plant heights and days after transplanting (DAT), however, accuracy of the equation to estimate plant height was linear equation. A non-rectangular hyperbola model was chosen as the response function of net photosynthesis. The light compensation point, light saturation point, and respiration rate were 29, 813 and $3.4{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. The shoot fresh weight showed a linear relationship with the shoot dry weight. The regression coefficient of the shoot dry weight was 0.75 ($R^2=0.921^{***}$). A non-linear regression was carried out to describe the increase in shoot dry weight of quinoa as a function of time using an expolinear equation. The crop growth rate and relative growth rate were $22.9g{\cdot}m^{-2}{\cdot}d^{-1}$ and $0.28g{\cdot}g^{-1}{\cdot}d^{-1}$, respectively. These models can accurately estimate plant height, net photosynthesis rate, shoot fresh weight, and shoot dry weight of quinoa.

• The Mathematical Education
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• v.61 no.1
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• pp.109-126
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• 2022

The purpose of this study is to explore how well teachers anticipate students to understand and solve equations. For this purpose, a questionnaire of the equal sign was developed, and 20 fourth-grade classes were selected as research participants. Teachers in each class were asked to predict various strategies on how their own students would respond to the questionnaire, and a total of 450 students from the 20 classes solved the questionnaire. As a result of the analysis, the teachers could predict students' computational strategies and relational strategies easily but did not fully understand that some students used both strategies or employed incorrect computational or relational strategies. The students tended to use relational strategies better than the teachers expected. They also employed operational strategies more often than the teachers expected. The teachers predicted that students' strategies would be influenced by the types of the problems such as equation-structure items and equation-solving items, whereas the students were more influenced by the forms of equations in the problems. Based on these results, several implications for the knowledge to which teachers needed to attend were discussed so that elementary school students could enhance the relational understanding of the equal sign.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.183-187
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• 2000

본 논문에서는 불확실성을 가지는 TS 퍼지 시스템을 안정화시킬 수 있는 제어기를 제안하고, 선형행렬부등식(Linear Matrix Inequality : LMI)을 이용한 설계 방법을 제시하였다. 그리고, 간단한 예제를 통하여 제안된 기법의 응용 가능성을 확인하여 보았다.

• The Science & Technology
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• v.28 no.1 s.308
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• pp.72-73
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• 1995

「이달의 과학자」로 선정된 최희준교수는 물리현상 및 공학현상의 수학적 모델인 포물선형 편미분방정식과 변분부등식 해의 행태 등의 연구로 과학기술분야의 균형적 발전에 큰 공을 세웠다.

• The Science & Technology
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• v.29 no.4 s.323
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• pp.76-77
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• 1996

포항공대 최재경교수는 미분기하학으로 박사학위를 받은 후 등주부등식을 연구해온 세계적 수준의 수학자다. 그는 1988년 곡면의 경계가 두개일때 등주부등식이 성립함을 사상 처음으로 증명했다. 이러한 연구결과는 지난 70년동안 수학자들이 해결하지 못했던 주목할만한 연구결과로 높게 평가받고 있다.

• Vending industry
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• v.2 no.4 s.5
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• pp.86-87
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• 2002

자판기 사업에 있어 환상 주입식의 마케팅정책은 이제 달라져야할 시점이 되었다. 자판기 사업은 '황금 알을 낳는 거위'다 라는 등식은 이제 더 이상 주효한 시점이 아니라는 사실을 냉혹히 인정해야 한다. 이 보다는 차라리 일정 고정수입을 보장하는 괜찮은 부업 아이템으로서 자판기 사업을 보는 시각을 가져야 한다. 사업에 대한 거품과 과대포장이 아닌 현실적이고 객관 타당성 있는 사업성이 차라리 보다 큰 대중적 소구력을 갖는다.

• Aerospace Industry
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• v.79
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• pp.26-29
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• 2002

우리나라에서 항공기 착륙장치 - 위아(주)로 통한다. 이러한 등식이 통용되기까지 위아의 노력은 국내 유일의 항공기 착륙장치 전문업체라는 타이틀 이전에 우리나라 항공산업의 발전과정과 그 맥락을 같이 해오고 있다. 그 결과 위아가 보유한 항공기 착륙장치에 관한 제조기술 및 일부 설계기술이 국내 항공기술 축적의 자존심을 지키고 있다. 또한 위아가 항공기 부품사업에서 단계별로 쌓은 기술축적은 항공기 부품의 국산화 과정을 보여주는 대표적인 케이스로도 주목받고 있다.