• 한국수학교육학회지시리즈D:수학교육연구
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• 제1권2호
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• pp.127-137
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• 1997

수세기는 초등 수학교육의 기초로서 보통 유치원 과정 이전부터 시작된다. 그러나, 서수와 기수의 구별된 사용의 중요성은 미국의 "학교 수학의 교과 과정과 평가 기준" (NCTM 1989)에서 뿐만 아니라 학교 교육의 현장에서도 많이 간과되고 있는 실정이다. 일반적으로 사용되는 수직선 (Number line)과 다르게 구조적으로 개발된 Hasse's structured number line을 사용하여 학생들에게 수세기의 의미와 기술을 가르친다면 구체적 경험을 통해 수학적 사고 능력을 키우고 개발하는데 도움이 된다. 만약 Hasse 의 9가지 수준에 따라 다양한 학습 활동을 개발하여 수업 계획을 세워서 학습을 진행한다면 수업은 역동적이며 매우 흥미로워 질 것이다. 학생들은 말로 나타내기(Verbalization)와 상상(Imagination)의 충분한 경험을 바탕으로 정신적 표현(Mental representation)을 개발하여 수세기 기초를 확립하고 나아가 연산을 쉽게 수행할 수 있을 것이다. 여기에 소개된 교구들과 학습 활동들은 초등 수학 교육이 암기 위주의 문답식이 아니며 얼마나 역동적이고 흥미로울 수 있나를 보여준다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권6호
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• pp.564-570
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• 2005

In the present study, the protective effects of Bcl-2 over-expression in a suspension culture (without any adaptation) and spent medium (low nutrient and high toxic metabolite conditions) were investigated. In the suspension culture without prior adaptation, the viability of the control cell line fall to 0% by day 7, whereas the Bcl-2 cell line had a viability of 65%. The difference in the viability and viable cell density between the Bcl-2 and control cell lines was more apparent in the suspension culture than the static culture, and became even more apparent on day 6. Fluorescence microscopic counting revealed that the major mechanism of cell death in the control cell line in both the static and suspension cultures was apoptosis. For the Bcl-2 cell lines, necrosis was the major mode of cell death in the static culture, but apoptosis became equally important in the suspension culture. When the NS0 6A1 cell line was cultured in spent medium taken from a 14 day batch culture, the control cell line almost completely lost its viability by day 5, whereas, the Bcl-2 still had a viability of 73%. The viable cell density and viability of the Bcl-2 cell line cultivated in fresh medium were 2.2 and 2.7 fold higher, respectively, than those of the control cultures. However, the viable cell density and viability of the Bcl-2 cultivated in the spent medium were 8.7 and 7.8 fold higher, respectively, than those of the control cultures. Most of the dead cells in the control cell line were apoptotic; whereas, the major cell death mechanisms in the Bcl-2 cell line were necrotic.

• 한국학교수학회논문집
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• 제11권1호
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• pp.97-115
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• 2008

고등학교 수학 수업에서는 실수 전체의 집합에서 뺄셈은 빼는 수의 덧셈의 역원을 더하고 나눗셈은 나누는 수의 곱셈의 역원을 곱하는 형식적인 관점으로 다룬다. 본 논문에서는 정수의 사칙계산 지도에 있어서 중학교 수학 수업에서 사용되는 직관적 모델(수직선 모델, 셈돌 모델)과 고등학교 수학 수업에서 제시되는 형식적 관점과의 연계에 대하여 논의하고자 한다. 직관적 모델을 이용하여 정수의 뺄셈을 덧셈을 이용하여 나타내는 방법의 의미를 재조명하고 이를 바탕으로 (음수)${\times}$(음수)가 양수임을 지도하는 새로운 방안을 제안하고자 한다. 직관적 모델의 일관성 있는 활용에 바탕을 두고 Treffers(1986)와 Freudenthal(1991)이 제안한 수평적 수학화(horizontal mathematization)의 과정을 통하여 정수의 사칙계산을 지도하는 이 방법은 중학교와 고등학교에서 정수의 사칙계산 수업에 참여하는 교사와 학생들 모두에게 나타날 수 있는 단절(박임숙, 2001)을 제거할 수 있는 방안이 될 것이다. 또 이것은 중 고등학교에서 다루는 수 체계들이 대학과정 대수학에서 다루는 추상적인 수 체계(group, ring, field)와 계통성을 가진 하나의 개념구조를 형성한다는 사실을 학생들이 인지할 수 있는 밑바탕이 될 것이다.

• 한국초등수학교육학회지
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• 제20권3호
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• pp.431-456
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• 2016

본 연구는 수직선의 적절한 도입 시기와 활용 방법을 탐구하여 초등학생들의 수개념 학습 지도를 위한 시사점을 제공하고자 하였다. 이를 위하여 수 개념 형성을 위한 수학적 모델인 수직선, 빈 수직선, 이중 수직선과 수 세기와 수 개념의 발달유형에 대하여 고찰하였고, 실제 초등학생들의 수직선 도입 시기와 활용 방법에 대한 사례 연구 결과를 분석하였다. 첫째, 수직선 도입을 2학년부터 실시하여 수직선의 은유적 개념에 대한 이해를 통해 이어지는 수 개념 학습에 도움이 될 수 있도록 조정할 필요가 있다. 둘째, 덧셈과 뺄셈과 같은 연산과정에서 다양한 사고 전략을 시각적으로 그려낼 수 있는 수학적 모델인 빈 수직선과 곱셈적 비교 상황이나 나눗셈이 이루어지는 상황인 등분제와 포함제, 비율이나 비례배분의 이해를 위한 시각적 모델인 이중 수직선을 적극적으로 도입하고 활용할 필요가 있다. 셋째, 수직선이나 빈 수직선, 이중 수직선을 도입할 때, 수직선의 은유적 개념을 충분히 이해할 수 있도록 구체적인 안내와 활용 방법에 대한 학습의 필요성을 제안하였다.

• International Journal of Ocean System Engineering
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• 제3권4호
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• pp.209-217
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• 2013

This paper presents a mooring design procedure for a floating offshore wind turbine. Offshore environmental data for Jeju are taken from KHOA (Korea Hydrographic and Oceanographic Administration) and used for the environmental conditions in numerical analyses. A semi-submersible-type floating wind system with a 5-MW-class wind turbine studied by the DeepCwind Consortium is applied. Catenary mooring with a studless chain is chosen as the mooring system. Design deliverables such as the nominal sizes of chain and length of the mooring line are decided by considering the long-term prediction of the breaking strength of the mooring lines where a 100-year return period is used. The designed mooring system is verified using a fatigue calculation based on rain-flow cycle counting, an S-N curve, and a Miner's damage summation of rule. The mooring tension process is obtained from time-domain motion analyses using ANSYS/AQWA.

• 한국해양공학회지
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• 제27권4호
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• pp.22-32
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• 2013

This paper presents the conceptual design procedure for the taut-leg mooring lines of a floating-type combined renewable energy platform. The basic configuration of the platform is determined based on an understanding of floating offshore plants. The main dimensions and mass distribution are determined based on a hydrostatic calculation. To identify the motion history of the floating platform and the tension history of the mooring lines, a hydrodynamic analysis is executed using Ansys.Aqwa. This helps in the selection of the best configuration for the mooring system such as the number of mooring lines, wire types, anchored positions, etc. In addition, the fatigue life of the mooring lines can be predicted from the tension history using the rain-flow cycle counting method.

• 대한한방내과학회지
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• 제24권1호
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• pp.134-143
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• 2003

Objectives : We performed this study to understand the molecular basis of the antitumor effect of Saussurea lappa, Pharbitis nil, Plantago asiatica and Taraxacum mongolicum, which have been used for cancer treatment in Korean traditional medicine. Design: We analyzed, the effect of these medicinal herbs on proliferation and apoptosis of tumor cells and its association with gene expression, We performed semi-quantitative reverse transcription-polymerase chain reaction(RT-PCR) analysis of cell cycle- and apoptosis-related genes using a gastric cancer cell line AGS. Results : Cell counting assay and $[^3H]thymidine$ uptake analysis showed that Saussurea lappa and Pharbitis nil strongly inhibit cell proliferation of AGS in a dose-dependent manner. Interestingly, gene espression assay revealed that mRNA espression levels of c-Jun, c-Fos, c-Myc, and Cyclin D1 were markedly decreased by Saussurea lappa and Pharbitis nil. Furthermore, Saussurea lappa was identified to activate expression of the p53 tumor suppressor and its downstream effector $p21^{Wafl}$, which leads to $G_1$ cell cycle arrest and apoptosis. These observations suggest that the anticancer effect of Saussurea lappa and Pharbitis nil might be associated with their regulatory capability of tumor-related gene expression.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1999년도 춘계 학술발표회 논문집
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• pp.171-176
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• 1999

Nondestructive inspection and accompanying life analysis based on fracture mechanics were the major conventional methods for evaluating remaining life of critical high temperature components in power plants. By using these conventional methods, it has been difficult to perform in-service inspection for life prediction. Also, quantitative damage evaluation due to unexpected abrupt changes in operating temperature was almost impossible. Thus, many efforts have been made for evaluating remaining life during operation of the plants and predicting real-time life usage values based on the shape of structures, operating history, and material properties. In this study, a core software for on-line life monitoring system which carries out real-time life evaluation of a critical component in power boiler(high temperature steam headers) is developed. The software is capable of evaluating creep and fatigue life usage from the real-time stress data calculated by using temperature/stress transfer Green functions derived for the specific headers and by counting transient cycles. The major benefits of the developed software lie in determining future operating schedule, inspection interval, and replacement plan by monitoring real-time life usage based on prior operating history.

• 전기학회논문지
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• 제65권7호
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• pp.1257-1262
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• 2016

The purpose of this study is to evaluate whether to take a medicine based on a measuring data using textile proximity sensor. We developed a proximity sensor of ring type using conductive textile, and acquired a data in accordance with the quantity of each pills. To evaluate our approach, we designed an experimental protocol that is counting pills subtracting the one which contains range of 0 T(Tablet, 4,100mg) from 20 T. And, The experiments were performed a nine times in the same way. In order to remove a noise and smoothen data, data preprocessing were performed using resampling method and moving average filter which has ten points. Then, we calculated a linear trend line equation, and analyzed a correlation between pill quantity and trend line equation. As a results, correlation coefficient was shown at 0.833 through using a Spearman's correlation method and we could be determined that data was continuos decreases when take a medicine.

• 한국환경보건학회지
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• 제30권5호
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• pp.469-480
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• 2004

The radon concentrations were measured to survey distribution of radon concentrations in Seoul subway stations. The radon concentrations in air and water were measured at seventeen subway stations(Mapo, Chungjongno, Sodaemun, Kwanghwamun, Chongno3ga, Ulchiro4ga, Tangdaemun, Sangildong on Line 5;Nowon, Chunggye, Hagye, Kongnung, Taenung, Mokkol, Chunghwa, Sangbong, Myomok on Line 7) using the $RAdtrak^{TM}$ radon gas detector, Pylon AB-5 continuous passive radon detector and liquid scintillation counting method from January to May 1999. The major results obtained from this study were as follows: The long-term mean concentrations of radon were $61.8\;Bq/m^3$ in office, $78.9\;Bq/m^3$ in platform, $38.2\;Bq/m^3$ in concourse and $20.1\;Bq/m^3$ in outdoor, respectively. These levels were less than the action level ($148\;Bq/m^3$) of the U.S. EPA. The highest level of short-term mean concentrations was $116.55\;Bq/m^3$ at Chongno3ga station on the 5th line subway stations, while the lowest mean concentration was $19.55\;Bq/m^3$ at Mokkol station on the 7th line subway stations. The highest concentration of radon in the road water and storing underground water in the subway stations was $234.7\;KBq/m^3\;and\;155.5\;KBq/m^3$ in Sodaemun subway station, respectively. The results suggest that radon concentration in subway stations seems to be affected by ventilation and radon concentratin in underground water in the subway stations.