• 한국경영과학회지
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• 제32권3호
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• pp.17-31
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• 2007

In this paper, we consider a service system with bi-functional servers, which can switch between the primary service room and the secondary room. A service policy is characterized by the switching paints which depend on the queue length in the primary service room and the service level requirement constraint of the secondary room. The primary service room is modeled as a Markovian queueing system and the throughput of the primary service room is function of the total number of bi-functional servers. the buffer capacity of the primary service room, and the service policy. There is a revenue obtained from throughput and costs due to servers and buffers. We study the problem of simuitaneously determining the optimal number of servers, buffer capacity, and service policy to maximize profit of the service system, and develop an algorithm which can be successfully applied with the small number of computations.

• 대한기관식도과학회지
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• 제3권1호
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• pp.164-168
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• 1997

Multiple primary tumors in the head and neck are not uncommon, however those in the thyroid and the larynx are known to be very rare. In most cases of multiple primary tumors involving the thyroid and the larynx, lesions are observed usually simultaneously and thyroid tumors are found incidentally during the laryngeal tumor surgery. In rare cases, thyroid tumors are found metachronously after radiation therapy of laryngeal cancer. The authors recently experienced a case of multiple primary tumor involving the thyroid and the larynx, in which thyroid papillary carcinoma was the index tumor and the laryngeal squamous carcinoma was the meatachronous second tumor. Both tumors showed aggressive local extension and regional nodal meatastasis with tumor collision in the same node. The patient died of recurrent or of residual squamous carcinoma shortly after main surgical treatment index thyroid cancer.

• 한국초등과학교육학회지:초등과학교육
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• 제32권1호
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• pp.47-59
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• 2013

The purpose of this study is to investigate the perception about STEAM education of primary teachers who have developed and applied STEAM education to their students through teacher training program. For this study, 101 among 172 attendance are responded to questionnaire of three categories consisting of development and application teaching material for STEAM instruction, and spreading STEAM education. The major findings are as follows: First, when primary teachers develop materials for STEAM education, they consider applicabilities in real classes. Second, they feel the burden of time when they develop STEAM material. Third, they think that their own program has significant educational effectiveness and that students enjoyed the program. Especially, they think that STEAM education program can raise students' interest about learning. Fourth, primary teachers point out the constraints for application of STEAM education program, which are lack of expertise and difficulty acquiring class time. Fifth, primary teachers evaluate the effect of STEAM education program on primary education is positive, and they answer that we need many teaching materials for STEAM education, operating as a regular curriculum, and securing budget. In order to spread STEAM education in field of primary education successfully, administrators have to consider and reflect the voice of teachers.

• Journal of Communications and Networks
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• 제16권3호
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• pp.280-292
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• 2014

This article presents a novel cooperative spectrum sharing (CSS) scheme. The primary transmitter transmits a complex Quadrature amplitude modulation (QAM) signal in the first phase, and CSS occurs in the second phase. The secondary transmitter with the largest forwarding channel gain among the nodes that successfully decode the primary signal in the first phase is selected for CSS. This selected node employs a pulse-amplitude modulation (PAM) signal for primary information message (IM) instead of the QAM signal, and it employs a modified PAM signal for the secondary IM. The proposed modified PAM signal depends on the amplitude of the primary PAM signal. This method results in no mutual interference and negligible primary interference constraint and allows a higher degree of exploitation of spatial diversity, thus enabling increase in secondary power to improve primary transmission. The outage performance is enhanced in both the primary and secondary systems. The critical region, in which the primary outage performance is enhanced with the proposed CSS scheme, can be adjusted and widened by varying either the modulation cooperation sharing factor or the number of secondary transmitters.

• 대한소아치과학회지
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• 제11권1호
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• pp.145-150
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• 1984

Author have measured the depth of gingival sulcus of the primary teeth. 333 teeth were selected from the children who attended on the department of pedodontic, College of dentistry, Yonsei University, and kindergarten children at Won Ju city aged from 1 year 8 months to 10 year 2 months. 1998 point were measured. The results were as follows. ; 1. Facial surface was the shallowest in sulcus depth compared with other surfaces. It was 1.56 mm. The depth of sulcus in lingual surface was deeper than facial. 2. The deepest part of each surface was mesial and distal, There were no statistical differences between mesial and distal part of the sulcus depth. 3. The mean sulcus depth of each tooth was as follows. Primary central incisor.....1.71mm. Primary canine....1.75mm. Primary second molar.....2.03mm. 4. The mean sulcus depth of upper was 1.86mm, and the lower was 1.76mg. The upper tooth was deeper than lower in sulcus depth. 5. The lower primary central incisor had the shallowest sulcus and the upper 2nd primary molar had the deepest compared with other tooth. 6. There wasn't specific statistical differences between the age groups of primary dentition and mixed dentition.

• 대한소아치과학회지
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• 제51권1호
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• pp.99-108
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• 2024

Early loss of the primary maxillary second molar can lead to complications in which mesial drift of the adjacent first molar (M1) can disturb eruption of the succedaneous second premolar (P2). This study reports two cases of space loss for P2 caused by early exfoliation of its predecessor. After the eruption of the first premolar, the Jones jig appliance was used to distalize M1 and regain space for the eruption of P2. The appliance was further utilized to align the palatally erupted P2 into the dental arch. In both cases, the space and corrected position of P2 were well maintained. Early exfoliation of the primary second molar caused by mesial encroachment of M1 is a common phenomenon, and pediatric dentists should attend to this during routine examinations. An appropriate intervention should be initiated when the primary second molar is lost during the mixed dentition period. If used with careful anchorage control, the Jones jig appliance can effectively resolve this problem.

• 대한소아치과학회지
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• 제34권4호
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• pp.579-589
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• 2007

본 연구에서는 최근에 개발된 치과용 접착제를 대상으로 유치와 영구치의 법랑질과 상아질에 대한 결합력을 비교 평가하여 임상에서 상아질 접착제를 적절하게 선택하는데 도움을 주고자 시행하였다. 실험재료로 Adper Scotchbond Multi-purpose Plus Adhesive (SM; 3M ESPE, USA), Adper Single bond 2 (SB; 3M ESPE, USA), Clearfil SE Bond (SE; Kuraray Medical Inc., Japan), Adper Prompt L-Pop (PL; 3M ESPE, USA), G-Bond (GB; GC Cooperation Toyko, Japan)를 이용하여 전단결합강도를 평가하여 다음과 같은 결과를 얻었다. 1. 유치 법랑질에서 전단결합강도는 SM이 $28.47{\pm}7.93\;MPa$로 가장 높았고 SB ($28.18{\pm}6.84$), PL ($24.02{\pm}6.14$), SE ($21.70{\pm}6.56$), GB ($17.70{\pm}6.68$) 순이었다. SM과 SB는 SE보다 통계적으로 유의하게 높은 결합강도를 보였으며, SM, SB, PL은 GB보다 높았다(p<0.05). 2. 유치 상아질에서 전단결합강도는 SE가 $28.72{\pm}14.44MPa$로 가장 높았고, PL ($20.10{\pm}6.13$), SM ($17.72{\pm}10.65$), SB ($15.48{\pm}2.66$), GB ($10.10{\pm}5.45$) 순이었으며 SE와 GB간에는 유의한 차이가 있었으나, 다른 군들 간에는 유의한 차이가 없었다. 3. 영구치 법랑질에서의 전단결합강도는 SB가 $28.36{\pm}5.68\;MPa$로 가장 높았고 SM ($22.77{\pm}4.63$), PL ($22.05{\pm}6.57$), SE ($21.74{\pm}4.62$), GB ($15.60{\pm}6.75$)순이었다. SB는 다른 접착제보다 통계적으로 유의하게 높은 결합력을 나타냈으며, GB는 가장 낮은 결합력을 보였다(p<0.05). 4. 영구치 상아질에서의 전단결합강도는 SM이 $28.22{\pm}5.56\;MPa$로 가장 높았고, SB ($21.68{\pm}7.44$), SE ($20.13{\pm}9.88$), GB ($14.30{\pm}6.81$), PL ($14.18{\pm}5.88$)순이었으며, SM은 PL, GB와 유의한 차이가 있었다(p<0.05). 5. 유치의 법랑질과 상아질 간에는 SM, SB, GB에서 유의한 차이가 있었고, 영구치 법랑질과 상아질 간에는 PL에서 유의한 차이가 있었다(p<0.05). 6. 유치 법랑질과 영구치 법랑질 간에는 모든 접착제에서 유의한 차이가 없었으나, 유치 상아질과 영구치 상아질 간에는 SM과 SB에서 유의한 차이가 있었다(p<0.05).

• 대한소아치과학회지
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• 제35권4호
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• pp.642-651
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• 2008

본 연구는 2003년 1월부터 2007년 7월까지 전남대학교 병원 소아치과와 응급실에 치아 외상을 주소로 내원한 환자 570명(치아수: 1394개)을 대상으로 연령, 성별분포, 발생원인 및 장소, 손상 받은 치아의 위치 및 유형, 초진시 처치 등에 대한 조사를 통해 외상에 대한 적절한 진단과 치료에 도움이 되고자 시행하였다. 1. 성별에 따른 발생빈도는 1.9:1로 남자의 비율이 높았고, 나이에 따른 발생 빈도는 1세, $6{\sim}8$세, $17{\sim}18$세 때 높았다. 2. 외상의 원인은 유치열과 혼합치열에는 넘어진 경우가 가장 많았으며 영구치열에서는 교통사고와 싸움으로 인한 손상 빈도가 높았다. 외상을 입은 장소는 유치열은 집에서, 혼합치열, 영구치열에는 길에서 비율이 높았다. 3. 외상시 손상 받은 치아의 위치는 유치와 영구치 모두 상악 중절치의 비율이 높았다. 손상의 유형은 유치와 영구치 모두 치주조직의 손상이 많았는데, 유치는 아탈구, 진탕, 함입 순이었으며, 영구치는 아탈구, 진탕, 완전탈구 순이었다. 4. 초진시의 처치는 특별한 처치 없이 경과를 관찰하는 경우가 대부분이었으며, 유치는 33.1%, 영구치에서는 44.5%의 재 내원률을 보였다. 치주조직 손상 후 유치는 20.3%, 영구치는 26.6%의 치수 괴사율을 보였다.

• Journal of Digestive Cancer Research
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• 제5권1호
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• pp.32-36
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• 2017

In unresectable stage IV colorectal cancer, the role of palliative surgery is not defined clearly. The palliative surgery can be categorized into two surgeries; first, palliative primary tumor resection; second, palliative metastatectomy. Several retrospective studies reported initial palliative systemic chemotherapy in unresectable stage IV colorectal cancer did not increase primary tumor related complications such as obstruction, perforation and hemorrhage, so they insisted that primary tumor resection in asymptomatic stage IV colorectal cancer should be preserved. However, in terms of overall survival and cancer-specific or progression-free survival, several retrospective studies, especially using population-based big data, reported favored survivals in palliative primary tumor resection group. And also several studies reported that palliative metastatectomy such as liver resection without resection of lung metastasis showed better overall survivals. But those results from those studies came from retrospective studies and are likely to be affected by selection bias. Prospective randomized studies are needed to define the benefit of palliative primary tumor resection and metastatectomy in unresectable stage IV colorectal cancer. However, based on the updated evidences, the dogma that palliative primary tumor resection should be preserved in asymptomatic unresectable stage IV colorectal cancer should be questioned.

• 생명과학회지
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• 제10권6호
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• pp.617-620
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• 2000

Methanol extract of Sarcodon aspratus Berk. (S. Ito) was analyzed by thi layer chromatography, gas chromatography and mass spectrophotometer. Nine fractions from primary methanol extract were observed by TLC. Six fractions were observed by the second TLC analysis of the second and the third fractions. 27,28-digydrolanosterol({TEX}$C_{30}H_{52}${/TEX}O), ergost-7-en-3-ol({TEX}$C_{28}H_{48}${/TEX}O) were identified from two fractions of the second TLC analysis by mass spectrophotometer. The molecular weights of 27,28-dihydrolanosterol and ergost-7-en-3-ol were 413 and 400 respectively.