• 한국추진공학회지
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• 제22권3호
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• pp.40-45
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• 2018

고체 추진기관의 불량 발생 요인 중 가장 큰 부분을 차지하고 있는 추진제 기공 및 크랙은 추진제의 점도와 물성이 큰 영향을 미친다. 본 연구는 혼합형 고체 추진제의 한 종류인 나이트레이트 에스터 폴리이서(Nitrate Ester Polyester; NEPE)계열의 추진제에서 주로 사용되는 RDX의 입도 및 혼합 함량에 따른 추진제 점도, 기계적 물성 및 연소특성 변화를 관찰하였다. RDX 입도와 혼합 함량에 따라 미경화 추진제의 경시적 점도가 크게 변화가 되었으며, 이에 따른 추진제 물성 또한 변화가 있었다. 추진제의 낮은 점도와 안정된 기계적 물성을 동시에 고려할 때, RDX의 입도 및 혼합 함량은 NEPE계 추진제의 주요 인자로 확인할 수 있다.

• 품질경영학회지
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• 제46권4호
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• pp.1001-1014
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• 2018

Purpose: Autonomous driving cars, which are often represent the new convergence product, have been researched since the early years of 1900 but their safety assurance policies are yet to be implemented for real world practices. The primary purpose of this paper is to propose a modular concept based on which a safety assurance system can be designed and implemented for operating autonomous driving cars. Methods: We combine a set of key attributes of CE mark (European Assurance standard), E-Mark (Automobile safety assurance system), and A-SPICE (Automobile software assurance standard) into a modular approach. Results: Autonomous vehicles are emphasizing software safety, but there is no integrated safety certification standard for products and software. As such, there is complexity in the product and software safety certification process during the development phase. Using the concept of module, we were able to come up with an integrated safety certification system of product and software for practical uses in the future. Conclusion: Through the modular concept, both international and domestic standards policy stakeholders are expected to consider a new structure that can help the autonomous driving industries expedite their commercialization for the technology advanced market in the era of Industry 4.0.

• Imaging Science in Dentistry
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• 제54권2호
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• pp.129-137
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• 2024

Purpose: Patients with head and neck cancer (HNC) who undergo dental procedures during radiotherapy (RT) face an increased risk of developing osteoradionecrosis (ORN). Accordingly, new tools must be developed to extract critical information regarding the dose delivered to the teeth and mandible. This article proposes a novel approach for visualizing 3-dimensional planned dose distributions on panoramic reconstruction computed tomography (pCT) images. Materials and Methods: Four patients with HNC who underwent volumetric modulated arc therapy were included. One patient experienced ORN and required the extraction of teeth after RT. In the study approach, the dental arch curve (DAC) was defined using an open-source platform. Subsequently, pCT images and dose distributions were generated based on the new coordinate system. All teeth and mandibles were delineated on both the original CT and pCT images. To evaluate the consistency of dose metrics, the Mann-Whitney U test and Student t-test were employed. Results: A total of 61 teeth and 4 mandibles were evaluated. The correlation coefficient between the 2 methods was 0.999, and no statistically significant difference was observed (P>0.05). This method facilitated a straightforward and intuitive understanding of the delivered dose. In 1 patient, ORN corresponded to the region of the root and the gum receiving a high dosage (approximately 70 Gy). Conclusion: The proposed method particularly benefits dentists involved in the management of patients with HNC. It enables the visualization of a 3-dimensional dose distribution in the teeth and mandible on pCT, enhancing the understanding of the dose delivered during RT.

• 한국의학물리학회지:의학물리
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• 제21권1호
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• pp.99-112
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• 2010

국내에서 방사선치료를 위한 선형가속기 품질관리 프로토콜은 많이 개발되어 왔지만 선형가속기를 기반으로 하는 방사선수술장비의 품질관리 프로토콜 개발은 현재까지 거의 이루어져 있지 않고 있다. 이에 본 연구는 선형가속기 기반 일체형 방사선수술장비인 노발리스의 정확도 및 정밀도를 유지하기 위하여 일간, 주간, 월간, 연간에 주기적으로 시행하여야 하는 노발리스 품질관리 프로토콜을 개발 하고 품질관리 상태의 종합적 확인을 할 수 있는 해부학적 팬텀을 제작하였다. 이를 위하여 국내외의 선형가속기를 이용하는 방사선수술 품질관리 프로토콜의 수집 및 분석을 통해 필수적인 품질관리항목과 각 항목의 허용치를 정하였다. 노발리스 품질관리 항목은 기계적 정확도 부분과 방사선 전달 부분의 2가지로 분리하고 기계적 정확도 부분은 방사선발생 장치부, 보조장치부, 그리고 미세다엽 시준기부의 3가지 부분으로 방사선 전달부분은 치료 중심점 평가와 선량학적 평가의 2가지 부분으로 나누어 작성하였다. 최종적으로 노발리스 품질관리 유지를 위하여 시행하여야 하는 일간, 주간, 월간, 연간의 노발리스 품질관리 항목 표를 완성하였다. 완성된 노발리스 품질관리항목 표는 노발리스가 방사선수술에 적합한 정확도 및 정밀도를 유지하는데 필요한 지표로서 기여 할 수 있을 것이라 생각된다.

• 대한기계학회논문집A
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• 제22권3호
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• pp.644-653
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• 1998

In resistance spot weld, the assurance of weld quality has been a long-standing problem. Since the weld nuggets if resustance spot welding form between the workpieces, visual detection of defects in usually impossible. Welding quality of resistance spot welding can be verified by non destructive and destructive inspections such as X-Ray inspection and testing of weld strength. But these tests, in addition to being time-consuming and costly, can entail risks due to sampling basis. The purpose of this study is the development of the monitoring system based on fuzzy inference, aimed at diagonosis of quality in resistance spot welding. The fuzzy inference system consists of fuzzy input variables, fuzzy membership functions and fuzzy rules. For inferring the welding quality(strength), the experimental data of the spot welding were acquired in various welding conditions with the monitoring system designed. Some fuzzy input variables-maximum, slop and difference values of electrode movement signals-were extracted from the experimental data. It was confirmed that the fuzzy inference values of strength have a .${\pm}$5% error in comparison with actual values for the selected welding conditions(9-10.5KA, 10-14 cycle, 250-300 $kg_f$). This monitoring system can be useful in improving the quality assurance and reliability of the resistance spot welding process.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.521-525
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• 2011

Although the Korean construction industry has risen rapidly, the quality of the buildings is not met with the industry standard compared to the potential of the technology development and the cost of maintenance has been increased. The user's request for quality have been increased, but in the current building construction, the contractors only follow the specifications of design, material and technology, and their main concern is whether they are in right track with the specification or not. Thus, the necessity of developing technology has been ignored and sufficient opportunities for the development have not been provided as well. In the developed countries, in contrast, the quality assurance and the payment regulation system has been utilized for the active response to the changes of users' request. As a result of this, the maintenance cost has been decreased and the development of construction technology has been improved. Therefore the pay adjustment system is needed to create the improvement of the quality of the buildings by the contractors' earnest building construction. In order to introduce the pay adjustment system suitable to the Korean construction industry, this study presented the logical method of adjusting the construction cost and making payment with the pay adjustment index that is created based on the result of the performance test, after making a set of the indicators of the building performance standard and applied them to the targeted building.

• 산업경영시스템학회지
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• 제12권20호
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• pp.91-95
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• 1989

The activities of Quality assurance, in the past, were attached too much importance to the functions and performanced of products. Because of these practices, in general. product safeties were usually minimized corenen more disregarded from the central points. Qualify assurance should he accepted as one of a major management policies to satisfied with the users needs.

• 품질경영학회지
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• 제46권2호
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• pp.193-210
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• 2018

Purpose: The purpose of this study is to escape from the existing defense quality policy focused on government-led quality assurance for mass-produced items and to secure quality reliability of weapon systems through a defense quality policy paradigm shift based on designing a verification systems anchored on reliability through the enhancement of military supply quality control in the development stage, the enhancement of quality responsibility of the manufacturing contractor and other methods. Methods: For the shift to the quality-based defense quality policy, the status and the problems of the status quo are analyzed and the direction of future defense quality policy is suggested based on literature review of the concept of reliability and reliability in the field of defense, on case studies of global corporations and their quality policies, on the background on quality assurance in defense, and on case studies of quality policies in other government organizations, Results: Based on the case studies of quality policies in global corporations and other government agencies, the importance of preventive quality control from the early development stages, quality control based on the reliability of the materials and parts, and shift of the quality policy to a certification system to achieve these objectives were highlighted. Conclusion: To secure reliability of weapon system quality, the quality policy must be shifted to a system focused on reliability-based design and verification and there is a further need to enhance the operational efficiency and capacity of DTaQ based on studies and evaluation of weapon system reliability.

• 디지털콘텐츠학회 논문지
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• 제13권4호
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• pp.625-629
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• 2012

NGN 운용과정의 품질 보증을 위해 어떤 체계하에서 품질이 테스트 되어야 하는지 방법론을 도출하기 위해서 멀티미디어 트래픽을 중심으로 NGN 품질측정 프레임워크를 제시한다. 테스트베드는 NGN 운용과정에서 QoS 측정 메트릭스, 측정구간과 측정계위, 측정도구, 측정장비, 측정방법 및 측정결과 분석에 대한 일련의 프로세스와 방법론을 모델화한다. 이 모델은 향후 NGN 품질보증 활동에 활용토록 한다. 통신서비스 품질은 스스로 보장되지 않으며 끊임없이 측정되고 관리될 때에 만 품질 목표수준 확보가 가능하다. NGN 네트워크기술 패러다임 중요성을 감한할 때 NGN 운용상의 품질관리에 대한 연구는 앞으로 활발하게 추진되어야 할 핵심 소재이다.

• 대한치과의사협회지
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• 제48권11호
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• pp.790-796
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• 2010

Currently, KDA adopted new post-graduated program; advanced education general dentistry(AGD) for 3 years preparation. The AGO program provides the resident the opportunity to deliver the highest quality of comprehensive dental care to the broadest range of the population with a knowledge, comfort, and ease in treating the high risk patient. The purpose of this article is to study the assurance systems of AGO programs in USA and Japan and to suggest a piece of advice whether we choose the way of AGO program assurance system in Korea.