• 설비공학논문집
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• 제19권6호
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• pp.470-475
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• 2007

The present study has been conducted economic analysis through actual operation of electric heat pump (EHP) and gas engine driven heat pump (GHP) which are installed at the same building in the university. Cost items, such as initial cost, annual energy cost and maintenance cost of each system are considered to analyze life cycle cost (LCC) and economical efficiencies are compared. The initial cost is considered on the basis of actual cost, and annual energy cost is converted into the cost after measuring electricity and gas consumption a day LCC applied present value method is used to assess economical profit of both of them. Variables used to LCC analysis are electricity cost escalation rate, natural gas cost escalation rate, interest rate, and service lives when each of them are 4%, 2%, 8%, and 20 years. The result shows that EHP (148,257,306 won) is more profitable than GHP (161,239,296 won) by 8.05% (12,981,990 won).

• Journal of Periodontal and Implant Science
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• 제46권3호
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• pp.166-175
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• 2016

Purpose: Decision-making by dental and medical experts can be influenced by their biases, interests, and experiences, and academic arguments about controversial issues may additionally be considered indirect experiences capable of affecting decision-making. This study reports on the use of interactive communication devices to evaluate preferences and flexibility in decision-making among dental care providers who attended two distinct academic conferences. Methods: Two debates were presented by a team of two lecturers at two academic conferences (focusing on periodontology and implant dentistry, respectively) and the audience members of each session were surveyed. Before each lecture, two case modules about the diagnosis and treatment of multirooted molar lesions were provided, and interactive communication devices were used to collect responses about decision-making preferences in treatment planning immediately before and after a debate about treatment strategies. Results: In total, 81 and 84 completed answers from both conferences were obtained for the first and second case modules, respectively. The preferred treatment plan differed significantly according to the focus of the conference, and a tendency emerged for the clinicians participating in each conference to express uniform preferences. However, attending the debates resulted in significant changes in decision-making preferences regardless of the conference focus or the characteristics of the participants. Conclusions: Our findings suggest that providing continuing education via debates on controversial issues may be effective in widening conceptual knowledge and reducing biases among experts in the dental and medical fields.

• Journal of Periodontal and Implant Science
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• 제41권5호
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• pp.242-247
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• 2011

Purpose: The purpose of this study was to characterize the osseointegration of the fibronectin-coated implant surface. Methods: Sand-blasted, large-grit, acid-etched (SLA) surface implants, with or without a thin calcium phosphate and fibronectin coating, were placed in edentulous mandibles of dogs 8 weeks after extraction. All dogs were sacrificed forhistological and histomorphometric evaluation after 4- and 8-week healing periods. Results: All types of implants were clinically stable without any mobility. Although the bone-to-implant contact and bone density of the SLA implants coated with calcium phosphate (CaP)/fibronectin were lower than the uncoated SLA implants, there were no significant differences between the uncoated SLA surface group and the SLA surface coated with CaP/fibronectin group. Conclusions: Within the limits of this study, SLA surfaces coated with CaP/fibronectin were shown to have comparable bone-to-implant contact and bone density to uncoated SLA surfaces.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제31권6호
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• pp.505-509
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• 2009

Purpose: To evaluate the properties of antibiotic and NSAIDs administration before extract of the impacted mandibular third molar. Materials & Methods: No patient showed any sign of pain, inflammation, or swelling at the time of removal. A group of 50 patients was classified in Group 1(preemptive and oral medication was carried out for 3 days postoperatively, N=23) and Group 2(oral medication was carried out for 3 days postoperatively, N=27) subgroups. Clinical and radiologic factors were recorded for each case, and the rationale for assigning the patients to the groups was strictly random. The surgical technique was the same in all cases, and the follow-up period was 1 week. Parameters that were evaluated were infection, swelling, pain and differences in mouth opening. Results: We could not find any significant difference between the 2 groups regarding the evaluated parameters. Conclusion: The results of our study show that antibiotic and NSAIDs administration before the removal of lower third molars does not contribute to a decrease infection, swelling, pain or increase mouth opening. Therefore antibiotic and NSAIDs administration before the removal of lower third molars is not recommended for routine use.

• 대한치과교정학회지
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• 제48권5호
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• pp.304-315
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• 2018

Objective: The purpose of this study was to analyze initial displacement and stress distribution of the maxillofacial complex during dentoskeletal maxillary protraction with various appliance designs placed on the palatal region by using three-dimensional finite element analysis. Methods: Six models of maxillary protraction were developed: conventional facemask (Type A), facemask with dentoskeletal hybrid anchorage (Type B), facemask with a palatal plate (Type C), intraoral traction using a Class III palatal plate (Type D), facemask with a palatal plate combined with rapid maxillary expansion (RME; Type E), and Class III palatal plate intraoral traction with RME (Type F). In Types A, B, C, and D, maxillary protraction alone was performed, whereas in Types E and F, transverse expansion was performed simultaneously with maxillary protraction. Results: Type C displayed the greatest amount of anterior dentoskeletal displacement in the sagittal plane. Types A and B resulted in similar amounts of anterior displacement of all the maxillofacial landmarks. Type D showed little movement, but Type E with expansion and the palatal plate displayed a larger range of movement of the maxillofacial landmarks in all directions. Conclusions: The palatal plate served as an effective skeletal anchor for use with the facemask in maxillary protraction. In contrast, the intraoral use of Class III palatal plates showed minimal skeletal and dental effects in maxillary protraction. In addition, palatal expansion with the protraction force showed minimal effect on the forward movement of the maxillary complex.

• 한국통신학회논문지
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• 제39C권8호
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• pp.681-687
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• 2014

최근 몇 년 간 스마트 폰과 같은 개인 스마트 디바이스들의 확산으로 인해 인터넷 트래픽이 급증하고 있다. 이는 지상에 있는 기지국뿐만 아니라 건물, 버스, 철도, 선박 등에 설치된 AP(Access Point)나 기지국에도 심각한 과부하를 야기한다. 따라서 이를 해소하기 위해 크루즈선과 같은 선박 내부에서 효과적인 콘텐츠 분배를 위한 통신시나리오를 제안한다. 또한 제안한 시나리오 안에서 기존의 단말 간 직접통신(D2D: Device-to-Device)을 확장하여 다중 단말 간(MD2MD: Multi-Device-to-Multi-Device) 직접 통신 네트워크를 구성하고 이에 적합한 전송기법을 제시한다. 제안한 선박 내 다중 단말 간 직접통신 방식은 STBC(Space-Time Block Coding) 전송기법, SM(Spatial Multiplexing) 전송기법, 그리고 하이브리드 STBC-SM 기법을 비교분석하여 전송률(throughput) 관점에서 향상된 성능을 보인 전송기법을 채택했다. 제안한 방식은 선박 내 통신 특히 사용자의 수가 많아 트래픽이 심하여 선박 내 설치된 AP의 과부하가 심할 경우 이를 분배하고 사용자들에게 효율적으로 보다 질 높은 콘텐츠를 제공할 수 있는 기술로 기대된다.

• 전자공학회논문지SC
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• 제48권6호
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• pp.71-81
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• 2011

일반적인 내연기관 자동차와는 달리, 전기자동차는 파워트레인을 구성하는 배터리, 인버터, 모터 등의 전기 동력 시스템들이 차량의 주행성능과 동역학 특성에 직접적인 영향을 준다. 따라서 전기 차량의 최종 운동 및 동특성을 예측하기 위해서, 기계 및 전기전자 복합 시스템을 세부적으로 모델링하고 이를 통한 전체 파워트레인의 해석이 필요하다. 본 논문에서는 전기자동차의 최종 출력 성능을 예측하고 분석하기 위한 전기자동차의 파워트레인 시스템의 동적 모델을 유도하였다. 전기적인 신호로부터 최종 기계 동력 시스템으로 전달되는 입출력 변수의 상관관계를 수학적으로 모델링하여 개발하였다. 또한, 전기자동차의 동특성을 시뮬레이션 할 수 있는 기준모델을 Matlab/Simulink 플랫폼 기반으로 개발하였으며, 이를 이용하여 유도된 수학적 분석 모델을 검증하였다. 이를 통하여 속도, 가속도, 추진력 등의 주요 차량 주행성능을 비교 분석하였다.

• The Journal of Advanced Prosthodontics
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• 제6권5호
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• pp.395-405
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• 2014

PURPOSE. This study aims to investigate the degree of subjective pain and the satisfaction of patients who have undergone an implant treatment using a computer-guided template. MATERIALS AND METHODS. A survey was conducted for 135 patients who have undergone implant surgery with and without the use of the computerguided template during the period of 2012 and 2013 in university hospitals, dental hospitals and dental clinics that practiced implant surgery using the computer-guided template. Likert scale and VAS score were used in the survey questions, and the independent t-test and One-Way ANOVA were performed (${\alpha}=.05$). RESULTS. The route that the subjects were introduced to the computer-guided implant surgery using a surgical template was mostly advices by dentists, and the most common reason for which they chose to undergo such surgery was that it was accurate and safe. Most of them gave an answer that they were willing to recommend it to others. The patients who have undergone the computer-guided implant surgery felt less pain during the operation and showed higher satisfaction than those who have undergone conventional implant surgery. Among the patients who have undergone computer-guided implant surgery, those who also had prior experience of surgery without a computer-guided template expressed higher satisfaction with the former (P<.05). CONCLUSION. In this study, it could be seen that the patients who have undergone computer-guided implant surgery employing a surgical template felt less pain and had higher satisfaction than those with the conventional one, and the dentist's description could provide the confidence about the safety of surgery.

• Journal of Periodontal and Implant Science
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• 제44권5호
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• pp.251-258
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• 2014

Purpose: The preferred material for bone augmentation beyond the envelope of skeletal bone is the bone block graft, due to its dimensional stability. We evaluated the necessity of rigid fixation for the bone block graft, and compared the bone regeneration and volume maintenance associated with grafting using a synthetic hydroxyapatite block (HAB) and an autogenous bone block (ABB) without rigid fixation on rabbit calvaria over two different periods. Methods: Cylinder-shaped synthetic HAB and ABB were positioned without fixation on the rabbit calvarium (n=16). The animals were sacrificed at 4 or 8 weeks postoperatively, and the grafted materials were analyzed at each healing period using microcomputed tomography and histologic evaluation. Results: Integration of the graft and the recipient bed was observed in all specimens, although minor dislocation of the graft materials from the original position was evident in some specimens (six ABB and ten HAB samples). A tendency toward progressive bone resorption was observed in the grafted ABB but not in the grafted HAB, which maintained an intact appearance. In the HAB group, the area of new bone increased between 4 and 8 weeks postoperatively, but the difference was not statistically significant. Conclusions: The nonfixed HAB was successfully integrated into the recipient bed after both healing periods in the rabbit calvaria. In spite of limited bone formation activity in comparison to ABB, HAB may be a favorable substitute osteoconductive bone material.

• 한국게임학회 논문지
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• 제6권3호
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• pp.67-76
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• 2006

본 연구에서는 온라인 게임의 이용자의 게임 몰입도가 PPL의 효과에 미치는 영향을 알아보고자 한다. 간접 광고 효과에 영향을 미치는 요인으로는 노출 빈도, Brand의 배치 형태, 식역하 지각에서의 자극, 제품에 대한 관여도, PPL에 대한 사전지식을 고려해 볼 수 있다. 본 연구에서는 이러한 변인요소들을 통제하고 게임매체의 특성인 몰입 정도를 조절하기 위하여 게임을 통해 광고에 노출된 그룹과 같은 자극을 영상을 통해 노출된 그룹으로 나누어 두 그룹의 PPL인지와 제품에 대한 태도변화에 대해 알아보았다. 게임몰입이 클 경우 광고에 대한 정보처리는 방해를 받았으며, 따라서 미디어에 삽입된 PPL광고의 인지율이 떨어졌다. 그러나 PPL의 배치요인에 따라서는 인지에 차이를 보였다. 이를 이용하여 고몰입 상태의 초점시각의 움직임에 따른 이미지 인식의 정확성을 조사하여 사용자의 인지에 따른 PPL 디자인 법을 제안하였다. 본 연구는 게임 내 PPL을 통한 수익구조의 잠재적 효과를 조명하며 전략적으로 게임내의 PPL을 디자인 하는 방법 에 대한 논의를 포함한다.