• 한국학교수학회논문집
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• 제2권1호
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• pp.15-30
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• 1999

For the purpose of turning learners' locus of control into internal-controllable variables, counseling materials were developed, and attribution counseling was given. The counseling effects were practically confirmed by way of teaching and evaluation in the actual classes, and furthermore the efforts to provide learners with successful experiences in learning were repeatedly made. As a result, the conclusions are as follows: 1. The procedure of Individual counseling for learning attribution based on individual standard grades and data of the variable order of merit apparently shows learners that if learners are to try their best in learning, they will surely go far in terms of learning in the near future. 2. The procedure of Individual counseling for teaming attribution based on achievement distribution in individual behavior-oriented fields suggests to learners that how to learn is as important as how much effort they make. Surely enough, learners are required to make more effective and efficient efforts, considering their own learning abilities. 3. With the above 1, 2 procedures involved, learners have attributed locus of causality in achievement to their internal-controllable causes. 4. With preparatory assignments according to learner's abilities provided, even slower learners came to be assured that their constant efforts could give rise to success in learning achievement. 5. Above all, it was confirmed that the learners' struggling attitude might well have a significant correlation with achievement success. The learners who are willing to attribute locus of causality in achievement to their internal-controllable causes or strenuous efforts and intrinsic motivation tend to be convinced that they can address themselves to whatever faces them, so they can set up specific learning goals fit for their abilities. Accordingly, they will bit by bit acquire successful experiences (often called 'Aha' experiences) and in turn, feeling the senses of self-efficacy and self-esteem enough to push their efforts even further, they can grow to form a positive self-concept. With one successful experience after another fed back into learners, they are gradually motivated to bring the oncoming achievement expectation to a higher level. To conclude, it is necessary that instruction leading to internal-controllable attribution should be provided, inducing learners to recognize success and failure in learning achievement as a result of their strenuous efforts.

• 한국산학기술학회논문지
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• 제14권6호
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• pp.3052-3060
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• 2013

기존 구조물에 근접하여 터널을 계획 할 때 상부 토괴하중 및 근접 구조물의 작용하중에 따른 이완영역의 범위를 고려하여 구조물 설치 가능범위 및 터널의 보강패턴을 제시하는 안전영역이 제시되고 있다. 그러나 이 안전영역에 대해서는 기존 구조물과의 이격 거리와 하중 조건 등에 대한 규정이 명확하지 않고 지층조건, 근접 구조물의 위치 및 작용하중 조건 등에 따라 안전영역이 달라질 것이지만 이에 대한 이론적 검증이 없는 실정이다. 본 연구에서는 터널굴착을 파악하기 위해 인한 지반 및 구조물의 거동을 2차원 및 3차원 수치해석을 수행하였으며 근접 구조물의 위치, 지반변형계수의 변화에 따른 터널의 안전영역과의 상관관계 및 적정성을 평가하였다. 안전영역의 범위는 지반변형계수가 높을수록 크게 나타나고 있으며 재평가된 안전영역 다이아그램에서 제약조건 아래 시공 가능영역은 전단파괴선이 스프링라인 하부의 인버트 연장선에서 나타나 안전영역이 상당히 확대되는 것으로 나타나고 있다.

• Korea-Australia Rheology Journal
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• 제13권4호
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• pp.205-217
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• 2001

This review article summarizes results of recent viscoelastic and dielectric studies for entangled cis-polyisoprene (PI) chains. The PI chains have the so-called type-A dipoles parallel along the chain backbone, and their slow viscoelastic and dielectric relaxation processes reflect the same global chain motion. However, this motion is differently averaged in the viscoelastic and dielectric properties, the former representing the isochronal orientational anisotropy of individual entanglement segments while the latter detecting the orientational correlation of the segments at two separate times (0 and t). On the basis of this difference, the viscoelastic and dielectric data of the entangled PI chains were compared to elucidate detailed features of the chain dynamics. Specifically, the molecular picture of dynamic tube dilation (DTD) incorporated in recent models was tested for linear and star PI chain. The comparison revealed that the DTD picture was valid for linear PI chains but failed for the star PI chains in the dominant part of the terminal relaxation. The failure for the star chains was related to the pre-requisite for the DTD process, rapid equilibration of successive entanglement segments through their constraint release (CR) motion: For the star chains, the dilated tube diameter expected in the terminal regime was considerably large because of a broad distribution of motional modes of the chains, so that the CR-equilibration required for DTD could not occur in time. The terminal relaxation of the star chain appeared to occur through the CR process before the expected DTD process was completed. The situation was different for the linear chain exhibiting narrowly distributed motional modes. The dilated tube expected for the linear chain was rather thin and the required CR-equilibration occurred in time, resulting in the success of the DTD picture. These detailed features of the chain dynamics was revealed only when the viscoelastic and dielectric properties were compared, demonstrating the importance of this comparison.

• 한국도로학회논문집
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• 제2권4호
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• pp.101-109
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• 2000

본 연구는 아스팔트 덧씌우기 포장에 야기되는 반사균열 실내 시험을 통해 여러 보강된 혼합물의 반사균열 저항성에 따른 피로수명을 추정하기 위해 수행되었다. 아스팔트 개질재로는 LDPE, SBS 및 카본블랙을 이용하였고 보강재로는 합성섬유(PF), 비닐(PV), 그리드 (GG)를 이용하였다. 공시체 몰드 바닥에 보강재를 미리 깐후 배합설계를 통해 얻은 아스팔트 혼합물을 부어 공시체를 제조하였다. 반복하중 하에서 균열이 있는 시멘트 콘크리트 위에 부착된 아스팔트 콘크리트 공시체 하단의 수평변위를 측정하여 각 혼합물별 균열지연에 따른 반사균열 피로수명을 추정하였다. 본 연구의 반사균열 실험 결과를 토대로 균열진전에 따른 각 혼합물별 피로수명에 대하여 이론적인 예측식을 개발 제안하였으며 예측식에 의한 추정치와 실측치와의 상관관계가 상당히 높게 ($r^2=0.95$이상) 나타났다.

• Journal of Chest Surgery
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• 제24권4호
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• pp.323-330
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• 1991

Residual significant tricuspid regurgitation after mitral valve operation may significantly increase postoperative morbidity and mortality. However, routine techniques to detect tricuspid regurgitation preoperatively and postoperatively are not accurate. Doppler echocardiography was performed preoperatively and postoperatively to assess its ability to evaluate and quantify the severity of tricuspid regurgitation. In 34 patients with tricuspid regurgitation secondary to mitral valvular disease the tricuspid regurgitations were semiquantified on a scale of 1 to 3+. The 34 patients were divided into two groups on the basis of severity of tricuspid regurgitation as assessed by preoperative Doppler echocardiography. Group I [8 patients] had mild[1+] regurgitation, and group II [26 patients] had moderate to severe[2 ~ 3%] tricuspid regurgitation. In all studied patients, preoperative Doppler echocardiographic studies for the degree of tricuspid regurgitation were correlated with clinical symptoms[including NYHA class] and hemodynamics[JVP and right ventricular systolic pressure], and used as the indicator to determine whether tricuspid annuloplasty should be performed or not. Patients with significant tricuspid regurgitation[group II ] had greater preoperative right ventricular systolic pressures and NYHA classes, although there was no correlation between them. The 8 patients with mild[1+] tricuspid regurgitation[group I ] didn`t undergo any procedure for the tricuspid regurgitation and their postoperative Doppler echocardiographic studies showed the less than mild[0 ~ 1+] tricuspid regurgitation, and the 26 patients with significant[>2+] tricuspid regurgitation, and the 26 patients with significant[>2+] tricuspid regurgitation[group II ] underwent tricuspid annuloplasty for the tricuspid regurgitation and the postoperative Doppler echocardiographic studies showed the findings similar to group I except 1 patient who underwent Carpentier`s ring annuloplasty and had severe right ventricular failure. Therefore, preoperative Doppler echocardiography can accurately assess the relative severity of tricuspid regurgitation. Importantly, postoperative Doppler echocardiography could conveniently determine the effect of tricuspid annuloplasty for the patients with significant tricuspid regurgitation. Doppler echocardiography may be an important diagnostic method both for evaluating the degree of residual tricuspid regurgitation after left heart operation as well as for determining which patients should undergo tricuspid valve repair.

• 한국수학교육학회지시리즈A:수학교육
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• 제46권1호
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• pp.53-67
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• 2007

During the recent years at a middle level Engineering School located at the local areas in Korea, more than 20 percent of freshmen had failed at their first College Mathematics. In consequence, many of them had hard time to survive at their major curriculums. The purpose of this study is to look for the main reasons of their failure and suggest an alternation of the present curriculum. Using the responses to the questionnaires and placement test scores, we studied the characteristics of the students' Mathematical abilities and analyzed how they were related to their grades of the First College Mathematics at the end of the first semester. The mathematical ability of the students at the middle level Engineering School turned out to range from bottom to top even though most of them revealed their interests towards Mathematics. The students with low scores at the placement test were more likely to fail at their first College Mathematics. Thus we suggest that the school should open a new preparation course ahead of the First College Mathematics for those who achieve low scores at the placement test and also professors should write proper books and develop ways of teaching.

• Restorative Dentistry and Endodontics
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• 제22권1호
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• pp.278-290
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• 1997

The purposes of this study were to evaluate and compare the pulpal anesthesia induced by an inferior alveolar nerve block and that by Gow-Gates technique, and to investigate the relationship between pulpal anesthesia and intraoral soft tissue responses. After one side of mandibule was anesthetized with inferior alveolar nerve block or Gow-Gates technique using 2 % lidocaine with 1 : 100,000 epinephrine in 19 volunteers of ages between 24 and 29 (16 males and 3 females, average age 25.9 yrs.), electric pulp tests were done on the canine teeth of the anesthetized side and contralateral one before, at 1 min, continued at every 5 minutes until 60 min, and every 10 minutes until 100 min after completion of local anesthetic injection. Degree of pulpal anesthesia was classified as anesthetic failure, possible anesthesia and complete anesthesia by the criteria based on the thresholds to electric pulp test of contralateral canine and the currents of the electric pulp tester. Subjective signs on the lower lip and tongue were checked and prick-pin tests were done on the buccal gingiva of the first molar, buccal and lingual gingiva of the canine tooth at 5, 10 and 20 min after the completion of anesthetic injection. Thresholds to electric pulp test, degree of pulpal anesthesia and relationship between the pulpal anesthesia and soft tissue responses were analyzed with SPSS, paired t-test, Wilcoxon matched-pairs signed-ranks test and correlation analysis. The results were as follows : No significant differences were found in the peak thresholds to electric pulp test, in the induction time to it and in the depth of pulpal anesthesia between inferior alveolar nerve block and Gow-Gates technique (p>0.05). There was no significant relationship between pulpal anesthesia and soft tissue responses in both inferior nerve block and Gow-Gates technique.

• 지질공학
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• 제17권3호
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• pp.339-350
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• 2007

암반에 발달하고 있는 단층이나 절리와 같은 불연속면뿐만 아니라 점토의 함량비, 팽창성 점토물질의 협재, 배수특성(drainage) 등은 암반의 붕괴여부를 결정하는 중요한 인자들이다. 특히 점토광물의 성분은 강우에 의한 암반붕괴를 예측할 수 있는 중요한 지표가 될 수 있다. 최근 사면이나 터널의 설계에서도 그 중요성이 점차 증가하는 추세이다. 본 연구는 니질천매암과 사질천매암이 호층을 이루고 있는 OO 터널의 선진시추코어(horizontal boring core)를 이용하여 단층발달에 따른 광물성분의 변화 및 이들이 불연속면의 역학성에 미치는 영향을 파악하고, 암석 구성물질과 파생된 점토광물을 비교하여 암반의 불안정성을 추정하기 위해 수행되었다. 연구방법은 시추코어 중에서 단층의 영향을 받은 구간과 비교적 신선한 구간에서 시료를 채취하여 박편을 제작하여 관찰하였고, 점토광물의 성분 및 함량을 분석하였다. 그리고 야외조사와 실내 시험으로 단층물질의 강도정수를 구하였다.

• 한국건축시공학회지
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• 제20권4호
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• pp.347-355
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• 2020

베트남의 경제 성장률과 도시인구는 꾸준히 증가함에 따라 베트남의 인프라 개발 건설 시장 규모는 더욱 커질 전망이다. 그러나 인프라 개발을 위한 베트남 정부는 재정 및 행정 능력의 한계로 이러한 문제를 해결하기 위한 방안으로 PPP를 채택하고 있다. PPP는 10년 이상 지속되는 장기 사업으로 사업 실패 시 장기적 큰 피해가 될 수 있어 위험관리가 매우 중요하다. 본 연구에서는 리스크 관리에 대한 리스크 요인의 영향과 관리정도 분석에 SOM분석을 제안한다. SOM분석 방법은 시각화 분석으로, 각 리스크 요인의 색상 패턴을 통해 상관 분석이 가능하다. 본 연구는 SOM을 활용하여 베트남 PPP 사업의 위험요인의 우선순위를 결정하고자 한다.

• 한국지반신소재학회논문집
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• 제12권3호
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• pp.55-64
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• 2013

본 연구는 포천석분을 재성형하여 등방압축-팽창시험과 구속압력을 달리한 일련의 비배수삼축압축시험을 실시하여 Lade 단일항복면 구성모델의 토질매개변수를 결정하였으며, 실험결과의 역해석을 통하여 단일항복면 구성모델의 적용성과 포천석분의 거동특성을 확인하였다. 그 결과 포천석분은 축변형률이 증가함에 따라 축차응력이 증가하는 경화현상을 보이고 있으며 큰축변형률에서 파괴되므로 실용적인 파괴기준을 검토할 필요성을 확인하였으며, 구성모델의 11개 토질매개변수를 이용하여 시험치를 역해석한 결과 응력-변형거동을 양호하게 예측하지만 항복함수에 관련된 토질매개변수를 파괴규준에 관련한 상관식과 상수로 역해석한 경우는 다소 상이한 양상을 보이고 있다.