• 한국초등과학교육학회지:초등과학교육
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• 제28권2호
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• pp.105-120
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• 2009

Critical Experiments (CE) in science classrooms mean, tentatively, critical situations as comparable to anomalous cases in scientific revolutions where the results of science experiments in schools are unclear, differ from the theory, or students misunderstand the purpose of the experiments. The purpose of this research is to identify what CE occurred during science classes and to investigate how elementary teachers handled them. To analyze how teachers recognized and handled CE, we selected nine typical CE from the $7^{th}$ Korean science curriculum. 125 teachers were selected from 8 districts' elementary schools in a local city. A questionnaire with photos of the nine CE above-mentioned was distributed to these teachers. The focus in this research was the way that each teacher handled the CE. We discovered that there were three basic ways in which teachers handled CE. When CE occurred, 51% of elementary teachers explained the correct result of the experiment (what should have happened) to the students while 40.7% of the teachers repeated to get the correct results. The focuses of handling CE varied. 57 % of the teachers focused on the 'materials' while 30% of the teachers focused on the 'theory'. The other focus was 'thinking'. Only 7.6% of the teachers answered that they gave students a chance to think about the reasons why the CE happened. By analyzing our survey results, we could determine what each teacher did as a follow up to the CE and their focus and reasoning for handling the CE this way. When the CE happened in the science class, few handled the CE with the point of view about purpose of doing experiment. As a result, students could not gain educational experience from the CE. If we use CE as a new method to teach science, it will be a good subject incorporating the nature of science in science education.

• 한국과학교육학회지
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• 제28권8호
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• pp.870-879
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• 2008

이 연구는 26종의 중학교 1, 2, 3학년 과학 교과서에서 '물질' 분야에 제시된 실험 활동에서 요구하고 있는 실험 수행 능력을 조사하고 분석하였다. 물질 분야에는 전체 7 단원에 걸쳐 총 359개의 실험이 제시되었다. 실험수행능력 분석틀에 따라 실험을 분석해 본 결과, 중학교 실험을 수행하기 위해서 다양한 실험수행능력이 필요하고, 학년별로 차이를 보였지만 전체적으로는 유사한 패턴을 가지고 있음이 조사되었다. 전학년에 걸쳐 결과 정리와 자료 해석 및 일반화 능력이 가장 많이 요구되고 대체 실험과 관련된 능력들은 상대적으로 빈도가 낮은 것으로 조사되었다. 3학년의 경우, 1, 2학년 실험과 비교하여 상대적으로, 실험 수행을 위한 세부적인 능력이 골고루 필요로 하는 실험이 많이 포함되어 있었다. 실험 상황 예측, 실험기구 설치, 측정기구사용, 오차원인 분석 능력은 2학년에게 상대적으로 많이 요구되는 것으로 조사되었다. 실험기구 설치 능력은 1, 2학년에서, 안전사고 위험 숙지 능력은 1, 3학년에서 상대적으로 많이 요구되는 능력으로 조사되었다.

• Communications for Statistical Applications and Methods
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• 제7권3호
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• pp.759-766
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• 2000

In order to design fractional factorial experiments which include some debarred combinations, we should select defining contrasts so that those combinations are to be excluded. Choi(1999) presented a method of selectign defining contrasts to construct orthogonal 3-level fractional factorial experiments which exclude some debarred combinations. In this paper, we extend Choi's method to general p-level fractional factorial experiments to select defining contrasts which cold exclude some debarred combinations.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 Asia Navigation Conference
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• pp.226-234
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• 2004

In this study experiments are conducted with a mid-layer type structure. This structure can operate not only at water surface but also in water. Six degrees of freedom oscillations of the structure and mooring force were measured by model experiments. From these experiments, it was shown that the lattice model has two peaks in the surge response curve and the oscillation amplitude and mooring forces increase according to the distance of separation between water level and upper deck.

• 공학교육연구
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• 제13권5호
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• pp.15-19
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• 2010

Upon request from the Tokushima Prefectural Senior High School of Science and Technology, two faculty staff members and eight students of The University of Tokushima visited the high school and set up a chemistry laboratory class for 59 students. Since the participating senior high school students were freshmen, four simple, safe and visual experiments were selected: 1) Water purification, 2) Surface modification, 3) Briggs-Rauscher reaction, and 4) Polymer synthesis and characterization. All experiments received a favorable reception as a follow-up questionnaire verified. Since the high school students enjoyed the experiments it is hoped that the results will strengthen the students' interest in chemistry. It was good opportunity for the observers; they recognized the difficulty of teaching students.

• 한국초등과학교육학회지:초등과학교육
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• 제25권4호
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• pp.396-406
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• 2006

In this study, elementary school students' science learning characteristics together with the levels of inquiry requirement in elementary school science experiment instruction were investigated in terms of the affective domain. We divided seventy-three students of the fifth ade into two groups according to the levels of inquiry requirement. After each instruction had been implemented, the characteristics of the students' learning in terms of the affective domain were compared and analyzed within the context of the levels of inquiry requirement. There were no significant differences between Level 1(LL) and Level 2(HL) groups in terms of the affective characteristics. These results may be caused by the burden imposed by the difficulty in thinking through and setting up the experimental methods. However, the HL group students' levels of interest in science experiments was higher than that of the LL group. In conclusion, the HL instruction contributed little to the improvement of affective characteristics. Some possible reasons might be that students felt difficulties with the somewhat unfamiliar instructions which required them to design and perform experiments. Higher levels of interest in science experiments amongst HL students' implies that well-organized and continuous exercises involving the design and performance of experiments could improve students' scientific affective characteristics.

• 인지과학
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• 제10권1호
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• pp.57-66
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• 1999

과학 분야의 교육에서 실험이 차지하는 비중은 다른 분야에 비하여 매우 크다. 과학실험은 여러 가지 실험구조요소 선택과 배치 및 적절한 실험 행위에 의하여 어떤 실험 상황이 만들어지고 자연법칙에 의해 상태 변화가 발생하여 실험을 진행하게 된다. 과학자 혹은 학생이 실험을 하면서 그 실험에 대한 인지모델을 내부적으로 구축하고 그 모델을 사용하여 시스템행위에 대한 인과추론을 함으로써 실험을 통해 진리 학습과 탐구를 하게 된다. 2차원 모델과 인과추론에 필요한 본체론 적 엔티티의 표현과 더불어 실험에서의 변화를 유도하는 추론방법을 본 연구에서 제시한다. 구현을 위해 화학영역의 실험을 선택하였고, 실험구성요소 (실험 기구와 시약) 및 물리적, 화학적 자연 법칙 뿐만 아니라, 실험 시스템 구조와 각 실험요소의 기능을 고려한 추상지식까지를 지식표현 대상으로 하고 있는 것이 본 연구의 특징이다. 학생이 임의의 실험을 할 수 있고 실세계와 유사한 현상을 보이는 가상 화학실험실을 개발하여 제안된 방법의 적정성을 확인하였다.

• Journal of Biosystems Engineering
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• 제42권2호
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• pp.80-85
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• 2017

Purpose: In this study, we attempted to analyze, by using a high-speed camera, the cutting shape as a function of cutting speed and feed rate. We compared the differences in cutting shape between domestic and foreign combines. Methods: Experiments were performed using plastic straws, and the results of two combine cutting blades, one from the Daedong Industry and one from Kuboda, were compared. The quality and performances of cutting were measured at three cutting positions: center and 68 cm to the left and right of the center. The feed rates were 0.6 m/s, 1.1 m/s, 1.6 m/s, and the cutting speeds were 600 RPM, 990 RPM, 1,380 RPM. For each speed, the cutting shape was measured three times, and the entire procedure was also repeated three times. Results: In the experiments, the domestic cutting blade achieved better results than the Japanese cutting blade. These results were obtained by studying the combination of feed rate and cutting speed, with the domestic combine attaining approximately 80% performance of the Japanese combine. We believe that additional data analysis is required, obtained from field experiments. Conclusions: The domestic cutting knives achieved better results than the Japanese cutting knives. These results are estimated from experiments conducted with different feed rates and cutting speeds; an in-depth analysis will require experiments in the real field with actual combines and a combination of multiple variables. Repeating the investigation on the length differences, broken and cut angle with various combinations of feed rate and cutting speed, will surely help to find the optimal cutting speed.

• 한국군사과학기술학회지
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• 제20권1호
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• pp.129-136
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• 2017

This paper aims to establish a guideline for ridership capacity of different rail vehicles for military passengers. Previous guideline is limited only to a Mungungwha(hauled by diesel locomotive) vehicle, but this paper expands the limitation to ITX- Saemaeul and urban rail vehicles classified to Electric Motivated Unit(EMU). The guideline considers both with and without personal armor conditions, and based on repetitive ridership experiments. The experiments are designed under considerations of the required number of soldiers for the sample spaces of the different rail vehicles. Moreover, the design tries to establish a concept of optimal capacity additionally to a traditional limiting ridership capacity. In order to do this, ridership comfort is questioned to participant soldiers repetitively over the experiments and all answers of them are surveyed as a results of it. The results of the experiments presented by this paper can be referenced to establish a new guideline on ridership capacity for Korean army.

• 대한방사선기술학회지:방사선기술과학
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• 제8권2호
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• pp.77-81
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• 1985

In this experiments the operation of the Geiger-Mueller tube is investigated by measuring the relationship between the count rate and the applied voltages, The length and slope of the plateau are characteristic of the tube. In our experiments, the average plateau length of the tube is extend for about 100 [V] and the slope 0.017 [%/V]. For normal counting purposes the working voltage is usually selected at value about 50 volts larger than the threshold of the plateau. To investigate the absorption of beta particles by matter. We performed an absorption experiments by using the Al absorber and Sr-90 ($0.125{\mu}Ci$) beta source. The maximum range of the beta radiation can be determined by visual extrapolation of the curve after subtraction of the constant background-rate and the maximum beta energy 2.09 [MeV] can be calculated from the range using an experimental relation.