• 로봇학회논문지
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• 제10권2호
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• pp.96-103
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• 2015

In this paper, we first point out the limitation of the existing methods in usability evaluation, and propose a new method to find tasks and users that can cause problems in the use of software applications. To deal with object-based applications, we define unit actions and divide a given task into the sequence of unit actions. Then, we propose a new measure to calculate the degree of lostness for the unit actions. In several experiments, we show the proposed method can represent the usability well while the previous method has a problem in object-based applications. We also find that the user's evaluation is more related to the proposed method than the previous method based on execution time through correlation analysis.

• 한국재료학회지
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• 제7권3호
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• pp.203-212
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• 1997

This paper evaluated the feasibility of laser consolidation for improving the properties of the plasma coated layer, Further, the mechanim of the degradation sequence of the chrome carbide layer applied on the turbine blades was postualted. The laser consolidation could be successfully applied for improcing the surface properties of the plasma coated blade, if a proper condition was carefully chosen. The consolidated layer had erosion & corrosion resistance and vond strength superiro to those of the as-plasma coated layer. The properties of the consolidated layer were strongly dependent upon the degree of dilution, especially on the Fe pickup from the substrate. The degradation of the plasma coating layer was thought to be a reault of the repeating action of the solid particle erosion, corrosion penetration through the pores and oxide films formed along the interlayer surface and impact spalling.

• Bulletin of the Korean Chemical Society
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• 제20권10호
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• pp.1153-1158
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• 1999

β-Cyclodextrin, amylose, and cellulose were partially methylated and acetylated in order to examine the relative reactivities of 2-, 3-, and 6-OH groups to alkylation and acylation. The partially methylated samples of the polysaccharides were treated with excess of ethyl iodide and sodium hydroxide in dimethyl sulfoxide to convert all of the free hydroxyl groups to ethyl ether groups. The partially O-ethylated and O-methylated polysaccharides were reductively cleaved with triethylsilane in the presence of trimethylsilyl methanesulfonate and borontrifluoride etherate (5 : 1 by mole) and the resulting 4-OH group was acetylated and benzoylated to form mixtures of eight 4-O-acyl-1,5-anhydroalditols. The relative ratio of the alditol esters were analyzed by gas chromatography to determine the degree of substitution at each position. A similar sequence of reactions was carried out with partially acetylated polysaccharides. The results indicated that the order of relative reactivities for methylation are 2-OH > 6-OH > 3-OH and for acylation are 6-OH > 2-OH > 3-OH regardless of the anomeric configuration.

• Journal of Ship and Ocean Technology
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• 제7권4호
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• pp.41-49
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• 2003

Welding deformation reduces the accuracy of ship hull blocks and decreases productivity due to the need for correction work. Preparing an error-minimizing guide at the design stage will lead to higher quality as well as higher productivity. Therefore, developing a precise method to predict the weld deformation is an essential part of it. This paper proposes an efficient method for predicting the weld deformation of complicated structures based on the inherent strain theory combined with the finite element method. A simulation of a stiffened panel confirmed the applicability of this method to simple ship hull blocks.

• Elastomers and Composites
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• 제54권3호
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• pp.232-240
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• 2019

A superabsorbent hydrogel (SAH) can absorb and retain water weighing more than a hundred times of their dry weight because of their three-dimensional hydrophilic structure. To fabricate an SAH, itaconic acid (IA) and vinyl sulfonic acid (VSA) were subjected to radical polymerization in an aqueous solution, wherein IA and VSA were neutralized, and then, a crosslinker and a thermal initiator were added in sequence. The structure of poly(IA-co-VSA) was characterized using attenuated total reflectance Fourier-transform infrared spectroscopy. We also studied the changes in the absorption properties of the SAH composites according to the polymerization temperature, degree of neutralization, type and content of the initiator used, and type and content of the crosslinker used. Thus, we could determine the effects of some synthetic factors on the absorption properties of the SAH.

• 한국통신학회논문지
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• 제25권3B호
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• pp.510-518
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• 2000

A new video interpolation technique based on variable skip rate of video sequence is proposed in this paper. in the proposed technique. the determination whether a frame is skipped or not is done by the degree of motion complexity of the frame. If the motion complexity of a frame is low the frame is skipped. otherwise it is coded and transmitted. To determine the motion complexity of a frame a new technique using MEF (moving edge in frame),the set of pixels considered as moving edges in a frame. is introduced. In the course of decoding and interpolating of receiver., the motion field is segmented. For the purpose of dividing vector field morphological filtering is applied. Morphological filtering also used to smooth the boundaries between the changed and unchanged region. In the simulation results, the proposed technique shows higher quality and lower fluctuation of picture quality than the conventional techniques on conditioning of the same bit rate.

• 보건교육건강증진학회지
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• 제18권3호
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• pp.37-58
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• 2001

This study placed its objectives in suggesting the basic data for setting up an approach to protect the educational environment, by analyzing the relevance between the misconducts of adolescence and the harmful environment around the school, as an object of study, middle school students and high school students all over the country. Thus, this study carried out the questionnaire survey, by the multi-stage of stratified sampling in 2,114 middle school and high school students from June 29, 2000 through July 29, 2000. And the results of analysis were as follows: 1. In case of the ratio of students using harmful environment, the electronic game room had the highest ratio (78.3％); next, the PC room (75.6％), the singing room (71.6％), and the cartoon room (34.3％). 2. In terms of the experiences of using the harmful environment according to the personal characteristics, high school students used it in a higher ratio, compared with middle school students (p〈0.001); the students, whose father graduated from a high school, comparatively used it much more(p〈0.05). Also, when a school is located near to amusement quarters or shopping centers, students used the harmful environment most highly (p〈0.001). And the differences were found to be statistically significant. 3. In case of the perceived susceptibility factors, the harmful environment was found to be used in lower ratio, by the students who answered “very so” to the question item, The more harmful environment facilities are positioned around school, the more student have the opportunities to use them. (p〈0.001). That is, the findings showed that the higher students' degree of perceived susceptibility factors was the less students used harmful environment facilities. The differences were statistically significant. In terms of the ratio of using harmful environment according to perceived seriousness factors, it was founded out that the students, who answered, “If I use any harmful environment facilities, it will be very harmful to myself.”. had the less opportunities of having used them, compared with the students who did not answer so (p〈0.001). This indicated that the higher the degrees perceived seriousness of students, the less they used harmful environment facilities. And the differences were statistically significant. In the side of the ratio of using harmful environment according to the perceived barriers, it was found out that there were any special large differences. That is, perceived barriers had nothing to do with students' using harmful environment. 4. As the result of having analyzed the factors influencing the behaviors of using harmful environment, the factor to explain the behaviors of using harmful environment was found to be the degree of perceived seriousness, among individual perceiving factors; next, the location of a school - one of personal characteristics, the degree of perceived susceptibility and ages, m sequence. 5. Among students' misconduct experiences, drinking was highest (21.6％), next, smoking (11.9％), drug abuse (4.3％), and sexual relations (1.6％), In sequence. Among other problematic behaviors, excessive waste was highest (14.6％); next, disobedience and lie (10.7％), night wandering (7.8％), and bad dressing and making-up (5.5％), in sequence. 6. In terms of the misconducts according to the behaviors of using harmful environment, compared with the students who did not commit any misconducts, harmful environment facilities were used more highly, by each group of students who experienced drinking (p〈0.00l), smoking (p〈0.001), sexual relations (p〈0.05), excessive waste (p〈0.001), disobedience ＆ lie (p〈0.001), and bad dressing ＆ making-up (p〈0.05). And the differences were statistically significant.

• 한국가정과교육학회지
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• 제17권4호
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• pp.133-156
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• 2005

이 연구는 중등 기술$\cdot$가정교과에서의 교육내용 적정성을 평가하기 위하여, 우선은 교육내용 적정성의 개념을 명료화하고, 이러한 적정성을 교과에서 평가하기 위한 준거를 선행연구를 근거로 하여 구안하였다 즉, 중등 기술$\cdot$가정 교과에서는 교과내용의 학습량, 내용의 난이도, 내용의 타당도, 내용의 연계 등의 4가지 준거를 교육내용의 적정성을 평가하는 준거틀로 설정하고, 적정성 평가에 대한 실증적인 자료를 수집하기 위하여, 학생 교사$\cdot$교수를 대상으로 한 전국적인 단위의 실태조사를 실시하였다. 그 결과, 첫째, 교육내용의 학습량에 대한 평가에서는 6차 교육과정에 비하여 $30\%$가량 감소하였다는 응답이 가장 맡았으나, 중학교 교사들은 '활동 중심인 교과 성격상 수업시수가 부족'하다는 이유를 지적하면서, 기술·가정 수업시간에 배우는 학습량이 '맡다'고 인지하고 있는 것으로 나타났다. 둘째, 교육내용의 난이도에 대한 평가는 전체적으로 '적절하다'는 응답(교사)과 '어렵다'(학생)라는 응답으로 서로 차이가 나타났다. 구체적으로 학생의 이해도가 떨어지는 단원은 중등의 기술 영역에서 중학교의 '제도의 기초', '기계의 이해' 단원, '전기$\cdot$전자 기술', '에너지와 수송기술' 단원이고, 가정 영역에서는 고등학교의 '가정생활의 설계' 단원만이 학생들의 이해정도가 떨어지는 단원으로 나타났다. 세째, 내용의 타당성과 관련해서는 기술·가정과의 교육목표를 고려할 때 중요하지 않다고 응답한 교육내용은 '제도의 기초', '컴퓨터와 정보처리', '자원의 관리와 환경'의 단원으로 나타났다. 넷째, 교육내용의 연계성은 교과 명칭에 대한 조사를 조사항목으로 설정하여 조사를 실시하였는데, 교사는 '기술$\cdot$가정으로 그대로 둔다'의 응답이 가장 많았고, 사대 교수들은 '기술$\cdot$가정으로 그대로 둔다'는 의견$(45.5\%)$보다, 초등 실과교과와의 연계성 확보의 차원에서 제3의 명칭으로의 개칭을 원하는 의견이 다소 많은 것으로$(50.5\%)$ 나타났다. 후속연구에서는, 이 연구에서 제시한 교육내용의 적정성 평가를 위한 준거틀에 대한 분석적이고 비판적인 검토를 통하여, 교과의 성격과 목표에 적합하게 평가 준거틀이 수정$\cdot$보완되고, 이러한 수정된 평가틀에 의하여 적정성 평가 연구가 지속되어, 우리 교과의 교육과정의 질 관리가 체계적으로 이루어져야 할 것이다.

• 한국산림과학회지
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• 제89권2호
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• pp.167-172
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• 2000

국내 5개 지역에서 채집한 비자나무(Torreya nucifera Siev. et Zucc.) 95개체를 대상으로 I-SSR 표지자를 분석하였다. 총 62개의 I-SSR 증폭산물(增幅産物)이 관찰되었으며, 그 중 7개의 증폭산물(增幅産物)은 분석된 95개 개체에서 단형성(單形性)이었다. 관찰된 전체 I-SSR 증폭산물(增幅産物)을 통합(統合)하여 분석한 결과 개체목에 대한 DNA지방판별(指放判別)이 가능하였다. 대부분의 유전다양성(遺傳多樣性)이 임분(林分)내의 개체목 간에 존재하는 것으로 나타났고(90.65%), 전체 5개 임분(林分)에서 유사한 수준의 유전다양성(遺傳多樣性)을 보였다. 집단간의 유전적(遺傳的) 분화(分化)정도는 심하지 않았다(${\phi}_{ST}=9.35%$). UPGMA법에 의한 유집분석(類集分析) 결과 각 집단의 유전적(遺傳的) 유연관계(類緣關係)는 임분(林分)의 지리적(地理的) 분포양상(分布樣相)과 일치(一致)하지 않았으며, 각 교점(交點)의 형성(形成)에 있어서 통계적 유의성이 없었고 따라서 전체 집단들이 유전적(遺傳的)으로 크게 분화(分化)되지 않았음을 알 수 있었다.

• 대한소아치과학회지
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• 제29권3호
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• pp.469-477
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• 2002

복합레진의 중요한 임상적 단점은 낮은 마모 저항성이며, 이와 관련된 하나의 인자로 수복물의 표면하 분해(subsurface degradation)가 고려되고 있다. 본 연구에서는 알카리성 용액(0.1N NaOH)에 현재 구치부 수복에 많이 이용되는 Z100(3M), Clearfil AP-X(Kuraray), Tetric Ceram(Vivadent)의 3종의 복합레진과 흐름성이 뛰어난 Aeliteflo(Bisco) 등 4종의 광중합형 레진을 보관하였을 때 각 제품의 분해저항성을 평가하고자 하였다. 분해저항성은 다음의 지표를 근거로 평가하였다. 1) 무게손실 - NaOH 용액에 노출 전후의 무게 측정, 2) Si 농도 - 시편을 제거한 용액은 ICF-AE분석기를 통하여 용액내로 용출된 Si 이온 정도 평가, 3) 분해층 깊이 - 용액에 보관한 시편을 연마하여 SEM을 이용하여 분해층의 깊이(${\mu}m$)를 측정하여 다음과 같은 결과를 얻었다. 1. 각 제품의 무게손실량은 Z100, TC, CL, AE 순으로 많았으며, AE, CL군과 TC, Z100군 사이에 유의한 차이가 있었다(p<0.05). 2. 각 제품의 표면하 분해층 깊이는 Z100, TC, CL, AE 순으로 깊었으며, AE. CL군과 Z100군 사이에 유의한 차이가 있었다(p<0.05). 3. 각 제품으로부터 용출된 Si 양은 Z100군이 가장 많고, AE, CL, TC순으로 많았다. 4. 무게손실량과 표면하 분해층 깊이 사이에 비교적 높은 상관관계를 보였다(r=0.71, p<0.05).