• 대한수학교육학회지:수학교육학연구
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• 제22권4호
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• pp.495-515
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• 2012

본 연구에서는 평면도형의 넓이에 대한 교사의 교수학적 내용 지식(PCK)을 설문지와 수업 관찰을 통해서 분석하였다. 연구 결과, 다음과 같은 4가지 결론을 얻을 수 있다. (1) PCK의 '수학 내용 지식' 영역에서 교사는 넓이의 개념, 넓이와 길이의 속성 구분을 정확히 이해하고 배열구조를 지도의 대상으로 인식하여야 한다. (2) PCK의 '수학과 교수 방법 및 평가에 대한 지식' 영역에서 교사는 교과 목표를 넓이의 개념 이해와 공식의 이해를 균형적으로 설정하고 평가해야 한다. (3) PCK의 '수학 학습에 대한 학생 이해 지식' 영역에서 교사는 설명 위주의 오류수정 보다 넓이의 개념의 이해에 대한 활동을 제시해야 한다. (4) PCK의 '수학과 수업 상황에 대한 지식' 영역에서 교사는 교과서에 대한 주체적 의식을 가지고 교과서의 활동을 보완하여야 한다.

• 한국농공학회논문집
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• 제62권5호
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• pp.93-103
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• 2020

In this study, we estimated soil moisture values using the Deep Neural Network(DNN) scheme at the mountainous regions. In order to test the sensitive analysis of DNN scheme, we collected the measured(at the soil depths of 10 cm and 30 cm) soil moisture and DNN input(weather and land surface) data at the Pyeongchang-gun(relatively flat) and Geochang-gun(steep slope) sites. Our findings indicated that the soil moisture estimates were sensitive to the weather variables(5 days-averaged rainfall, 5 days precedent rainfall, accumlated rainfall) and DEM. These findings showed that the DEM and weather variables play the key role in the processes of soil water flow at the mountainous regions. We estimated the soil moisture values at the soil depths of 10 cm and 30 cm using DNN at two study sites under different climate-landsurface conditions. The estimated soil moisture(R: 0.890 and RMSE: 0.041) values at the soil depth of 10 cm were comparable with the measured data in Pyeongchang-gun site while the soil moisture estimates(R: 0.843 and RMSE: 0.048) at the soil depth of 30 cm were relatively biased. The DNN-based soil moisture values(R: 0.997/0.995 and RMSE: 0.014/0.006) at the soil depth of 10 cm/30 cm matched well with the measured data in Geochang-gun site. Although uncertainties exist in the results, our findings indicated that the DNN-based soil moisture estimation scheme demonstrated the good performance in estimating soil moisture values using weather and land surface information at the monitoring sites. Our proposed scheme can be useful for efficient land surface management in various areas such as agriculture, forest hydrology, etc.

• 문화기술의 융합
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• 제10권3호
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• pp.349-358
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• 2024

본 연구는 2010년부터 2023년까지 담화를 주제로 연구한 연구들을 중심으로 담화 연구에 대한 언어병리학의 전반적인 흐름 살펴보고자 문헌 분석을 실시하였다. 논문 25편을 선정하여 연구의 현황, 연구 대상(연령 및 대상자 유형), 연구 방법(유형 및 과제) 측면에서 분석하였다. 그 결과 첫째, 담화 연구의 연도별 현황을 살펴보면 2015년을 기점으로 2010년 ~ 2014년에 비해 증가하고 있음을 확인할 수 있었다. 둘째, 연구 대상자는 대상자의 연령과 실험연구의 실험집단 및 통제집단의 유형을 살펴보았다. 먼저 대상자의 연령을 분석해 보면, 학령기(12편, 48.00%) 대상으로의 연구가 활발히 진행되었다. 연구대상자 유형 분석 중 실험집단 대상자 유형 분석을 살펴보면 Normal 집단의 연구가 4편(19.04%)으로 가장 많았고, 통제집단 대상자 유형 또한 Normal을 통제집단으로 설정하고 진행한 연구가 13편(61.90%)으로 가장 많았다. 셋째, 연구 방법 분석에서 연구 유형의 경우 실험연구가 21편(84.00%)으로 매우 편중되어 있음을 알 수 있었다. 시간 관점의 연구 유형은 횡단연구가 21편(84.00%)으로 비중이 높게 나타났으며 담화능력을 평가하기 위하여 비중 높게 사용된 연구 과제는 담화 산출로 총12편(48.00%)이었다. 본 연구는 언어발달 및 언어장애와 관련 있는 담화 관련 연구를 종합적으로 살펴보고 최근의 동향에 대한 경향성과 함께 담화 관련 연구가 나아가야 할 방향을 도모해 보고자 하였다. 본 연구는 국내 논문으로 제한하여 분석하였다. 후속 연구에서는 담화와 관련된 국외 연구까지 포함하여 연구의 흐름을 파악하고 논의가 이루어질 것을 바란다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2000년도 추계학술발표회 초록집
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• pp.3-4
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• 2000

Many researchers are interested in the synthesis and characterization of carbon nitride and diamond-like carbon (DLq because they show excellent mechanical properties such as low friction and high wear resistance and excellent electrical properties such as controllable electical resistivity and good field electron emission. We have deposited amorphous carbon nitride (a-C:N) thin films and DLC thin films by shielded arc ion plating (SAIP) and evaluated the structural and tribological properties. The application of appropriate negative bias on substrates is effective to increase the film hardness and wear resistance. This paper reports on the deposition and tribological OLC films in relation to the substrate bias voltage (Vs). films are compared with those of the OLC films. A high purity sintered graphite target was mounted on a cathode as a carbon source. Nitrogen or argon was introduced into a deposition chamber through each mass flow controller. After the initiation of an arc plasma at 60 A and 1 Pa, the target surface was heated and evaporated by the plasma. Carbon atoms and clusters evaporated from the target were ionized partially and reacted with activated nitrogen species, and a carbon nitride film was deposited onto a Si (100) substrate when we used nitrogen as a reactant gas. The surface of the growing film also reacted with activated nitrogen species. Carbon macropartic1es (0.1 -100 maicro-m) evaporated from the target at the same time were not ionized and did not react fully with nitrogen species. These macroparticles interfered with the formation of the carbon nitride film. Therefore we set a shielding plate made of stainless steel between the target and the substrate to trap the macropartic1es. This shielding method is very effective to prepare smooth a-CN films. We, therefore, call this method "shielded arc ion plating (SAIP)". For the deposition of DLC films we used argon instead of nitrogen. Films of about 150 nm in thickness were deposited onto Si substrates. Their structures, chemical compositions and chemical bonding states were analyzed by using X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and infrared spectroscopy. Hardness of the films was measured with a nanointender interfaced with an atomic force microscope (AFM). A Berkovich-type diamond tip whose radius was less than 100 nm was used for the measurement. A force-displacement curve of each film was measured at a peak load force of 250 maicro-N. Load, hold and unload times for each indentation were 2.5, 0 and 2.5 s, respectively. Hardness of each film was determined from five force-displacement curves. Wear resistance of the films was analyzed as follows. First, each film surface was scanned with the diamond tip at a constant load force of 20 maicro-N. The tip scanning was repeated 30 times in a 1 urn-square region with 512 lines at a scanning rate of 2 um/ s. After this tip-scanning, the film surface was observed in the AFM mode at a constant force of 5 maicro-N with the same Berkovich-type tip. The hardness of a-CN films was less dependent on Vs. The hardness of the film deposited at Vs=O V in a nitrogen plasma was about 10 GPa and almost similar to that of Si. It slightly increased to 12 - 15 GPa when a bias voltage of -100 - -500 V was applied to the substrate with showing its maximum at Vs=-300 V. The film deposited at Vs=O V was least wear resistant which was consistent with its lowest hardness. The biased films became more wear resistant. Particularly the film deposited at Vs=-300 V showed remarkable wear resistance. Its wear depth was too shallow to be measured with AFM. On the other hand, the DLC film, deposited at Vs=-l00 V in an argon plasma, whose hardness was 35 GPa was obviously worn under the same wear test conditions. The a-C:N films show higher wear resistance than DLC films and are useful for wear resistant coatings on various mechanical and electronic parts.nic parts.