실내 건축음향에서 직접음과 반사음의 상관관계에 관한 연구

전병주 연세대학교 공학대학원 2005 국내석사

The sampling test for the clearness of a sound system by measuring its'' direct and reflected sound was done in a gymnasium that can be used as a multipurpose hall in this study. The height, angle and direction of the sound speakers in the hall was relocated and its'' cabinet was strengthened to measure the inter-relationship of the direct and reflected sound. The following results was obtained from the theoretical approach, experiments and examinations on the sound system to find out if the hall was appropriate for the important events and the lecturing place. The measured value of the reflected sound for the pre-used system was 0.59 in the front location, which was a good clearness. But the measured value of STIRASTI in the middle and rear location was 0.45, which was bad. The ALCONS-% that measures the consonant loss was 3.45~5.35, which was satisfactory. The STIRASTI for the new system was 0.52~0.79 in every locations, which was good. The ALCONS-% was 2.4~4.37, which was good or excellent. It is difficult to determine that the clearness was improved greatly just by measuring the value of STIRASTI or ALCONS-%.But the measured value of C50 that counts the sound within 50ms as the direct sound has some differences. The distribute value of C50 in the pre-used system was -4.15dB ~ -1.23dB, which was extremely bad. But the value in the new system was -1.13dB ~ -5.72dB, which showed improved clearness in every locations except the location ⑤. The above results show that the sound clearness in a gymnasium can be improved to use as a multipurpose hall for general events and lectures by relocating the speakers and strengthening its'' cabinet even if the gymnasium has a long reverberation time and has never been considered for sound facilities. Hereafter, the study on the standard sounding system model for the multipurpose halls that can diffuse sound effectively by just relocating the pre-used systems should be continued. 본 연구에서는 사용용도가 점차 다양해지고 있는 다목적홀 중 대표적인 표본실험이 가능한 체육관을 선별하여 그 공간에서 현재 설치되어 있는 음향시스템의 직접음에 대한 반사음을 측정하여 명료도를 살펴본다. 그리고 홀의 특성을 고려하여 스피커를 재배치(높이, 각도, 방향) 하고스피커 캐비넷을 보강한 다음 직접음과 반사음의 상관관계를 측정하여 중요한 행사나 강연장으로서 사용이 가능한지 적합성을 찾고자 음향시스템에 대한 이론적 접근과 실험 및 고찰을 통하여 다음과 같은 결과를 얻었다. 기존시스템의 경우 직접음에 대한 반사음은 전방지점은 0.59정도로서 명료도가 적당한 수준이나 중앙지점과 후방지점의 STIRASTI를 보면 0.45정도로 명료도가 불량하였으며, 자음손실의 정도를 평가하는 ALCONS-%는 3.45~5.35정도로 양호한 편이었다. 신규시스템에서는 거의 전 지점에서 STIRASTI가 0.52~0.79로 명료도가 양호(GOOD)하였으며, ALCONS-%도 2.4~4.37정도로 명료도가 양호(GOOD)하거나 우수한(EXCELLENT) 상태까지 향상되었다. 여기서 STIRASTI값이나 ALCONS-%값만 비교해 볼때 명료도가 괄목할 정도로 개선되었다고 판단하기는 곤란하다. 그러나, 50ms이내에 도착한 음을 직접음으로 간주하는 C50의 측정값을 비교해 보면 기존시스템의 경우 C50의 측정값 분포는 -4.15㏈~ -1.23㏈로서 명료도가 극히 불량한 결과를 보였으나 신규시스템의 경우 C50측정값 분포가 -1.13㏈~5.72㏈로서 ⑤지점을 제외한 모든 지점에서 명료도가 우수하게 개선되었다. 위의 결과를 토대로 볼때, 건축음향이 전혀 고려되지 않은 체육관 으로 사용할 목적으로 건축된 공간에서 잔향시간이 길더라도 홀의 특성을 고려한 스피커의 배치 및 캐비넷 보강만으로도 명료도가 크게 개선되어 일반적인 행사나 강연 등 다목적 홀로서의 역할을 충분히 할 수 있다는 사실을 알 수 있었다. 향후 연구과제로는 기존시스템의 재배치만으로도 효율적인 음장확산을 할 수 있도록 다목적 홀에 대한 표준 음향시스템 모델 제시에 대한 연구가 지속되어야 하겠다.

베이비붐 세대의 성공적 노화에 미치는 영향요인 : Rowe & Kahn의 이론을 적용하여

전병주 한국교통대학교 일반대학원 2018 국내석사

본 연구는 베이비붐 세대의 성공적 노화 수준과 영향요인을 파악하기 위한 이차자료 분석연구이다. 한국에서 전체 인구의 15%를 차지하는 베이비붐 세대(1955년~1963년)가 노년기에 진입하면서 베이비붐 세대의 성공적 노화는 개인적 차원에서도 중요할 뿐만 아니라 노인 부양에 대한 사회적 부담과 직결되기 때문에 사회적 차원에서도 주요 관심사가 되었다. 그러나 지금까지 성공적 노화에 대한 연구는 이전 노인세대를 중심으로 보고되었고, 베이비붐 세대에 대한 연구는 매우 제한적으로 진행되었다. 이에 본 연구에서는 베이비붐 세대의 성공적 노화에 주목하고, Rowe & Kahn의 이론을 적용하여 베이비붐 세대의 특성을 보다 정확히 이해하고자 했으며, 그에 따른 성공적 노화를 위한 보다 실질적인 방안을 제시하고자 하였다. 이를 위하여 한국고용정보원에서 관리하는 제5차 고령화연구패널조사와 한국고용정보원에서 1962년~1963년 출생자를 추가 모집한 특별조사의 데이터를 결합하여 최종적으로 2,577명의 자료를 분석하였다. 본 연구에서의 자료 분석은 PASW Statistics 18.0을 이용하였으며, 주요 연구결과는 다음과 같다. 첫째, 본 연구에서 베이비붐 세대의 성공적 노화 수준(범위: 0~9점)은 6.36±1.39로 나타났으며, 베이비붐 세대는 6점(25.2%)과 7점(30.0%)에 가장 많이 분포하는 것으로 나타났다. 이와 같이 베이비붐 세대의 성공적 노화 수준은 대체로 높은 것으로 나타나 성공적 노화에 대해 긍정적으로 평가할 수 있다. 하지만, 본 연구와 이전 노인세대를 대상으로 한 선행연구는 성공적 노화의 개념과 측정기준이 다르기 때문에 각각의 연구결과에 대해 직접적으로 비교할 수 없으므로 본 연구결과의 해석에 주의를 요한다. 더욱이 본 연구에서는 성공적 노화의 하위요인에 따라 성공적 노화로 판단된 비율이 크게 다른 것으로 나타났다. 본 연구에서 만성질환 영역(90.6%), 신체적 기능(IADL; 94.8%)과 인지기능(93.9%)은 다른 영역보다 성공적 노화로 판단된 비율이 높은 것으로 나타났지만, 건강행태(15.9%), 주관적 건강상태(55.6%) 그리고 여가활동(57.6%)은 다른 영역보다 성공적 노화로 판단된 비율이 낮은 것으로 나타났다. 특히, 베이비붐 세대의 건강행태 중 금주와 규칙적 운동은 다른 요인보다 크게 취약한 것으로 나타났으며, 베이비붐 세대는 자신의 건강상태를 부정적으로 인식하는 경향이 높은 것으로 나타났다. 둘째, 성공적 노화에 대해 베이비붐 세대의 특성에 따라 집단별 수준 차이를 살펴보기 위해 t/F 검정을 실시한 결과, 조사대상자들의 성별(p<.001), 거주 지역(p<.001), 교육수준(p<.001), 배우자 유무(p<.001), 자녀관계 만족도(p<.001), 가구 순소득(p<.001), 용돈 수준(p<.001), 주거형태(p<.001)에 따라 집단별로 유의미한 차이가 나타났다. 즉, 베이비붐 세대 중에서 남성인 경우, 시 지역에 거주하는 경우, 대학교 졸업 이상인 경우, 배우자가 있는 경우, 자녀관계 만족도가 90점 이상인 경우, 가구 총소득이 생활비보다 많은 경우, 용돈이 21만원 이상인 경우, 자가에서 거주하는 경우에 성공적 노화 수준이 유의미하게 더 높은 것으로 나타났다. 셋째, 베이비붐 세대의 성공적 노화에 영향을 미치는 요인을 파악하기 위해서 다중회귀분석(multiple regression analysis)을 실시할 결과, 조사대상자들의 교육수준(p<.001), 배우자 유무(p=.002), 자녀관계 만족도(p<.001), 가구 순소득(p=.002), 용돈 수준(p<.001), 주거형태(p=.043)가 성공적 노화에 유의미한 영향을 미치는 것으로 나타났으며, 그 설명력은 12.4%로 통계적으로 유의미하게 나타났다(F=19.13, p<.001). 특히, 베이비붐 세대가 21만원 이상의 용돈(β=.20), 대학교 졸업 이상의 교육수준(β=.14), 90점 이상의 자녀관계 만족도(β=.13) 경우에 성공적 노화에 크게 영향을 미치는 것으로 나타났다. 이러한 연구결과는 베이비붐 세대의 성공적 노화를 증진하기 위해서 성공적 노화로 판단된 비율이 낮은 영역을 중심으로 관련 요인을 개선하고 보완하기 위한 방안이 조속히 수립되어야 함을 시사한다. 따라서 베이비붐 세대에게 취약요인으로 나타난 금주, 규칙적 운동 등의 건강행태를 실천하기 위한 중재프로그램을 제공하여 실질적인 건강증진행위를 도모하며, 자신의 건강상태에 대해 긍정적으로 평가할 수 있는 간호중재가 제공되어야 할 것이다. 이 과정에서 베이비붐 세대의 특성을 반영하여 자녀관계와 같이 중재가 가능한 요인을 개선하기 위한 프로그램을 동시에 진행하는 것이 바람직할 것이다. 그리고 베이비붐 세대의 성공적 노화를 위해 주요 영향요인을 강화할 수 있는 방안이 마련되어야 할 것이다. 이 과정에서 조사대상자들의 거주 지역과 용돈 수준 등 개인의 역량으로 극복하기 어려운 요인에 의해서도 집단별로 성공적 노화의 차이가 발생하고 있음을 고려하여 개인적 차원을 넘어 지역사회 차원에서 다각적이고 통합적인 접근이 이루어져야 할 것이다. 나아가 성공적 노화에 대한 보다 엄밀한 개념화를 시도하고, 사회적으로 합의된 측정요인을 발굴하여 베이비붐 세대의 성공적 노화에 대해 보다 정확히 규명해야 할 것이다.

금속3D프린팅 기술을 이용한 맞춤형 의료기기 제작 및 품질향상 방안에 관한 연구

전병주 국립금오공과대학교 대학원 2020 국내박사

본 연구에서는 맞춤형 의료기기 제작 및 품질향상 방안에 대한 연구를 수행하였다. 이를 위하여, 맞춤형 의료기기 제작을 위한 금속 3D프린팅 시스템 설계 및 제작방안을 소개하였다. 또한, 제안한 금속 3D프린팅 시스템을 실제로 제작함으로서 금속출력물의 성능을 분석하고자 하였다. 먼저 금속3D프린팅 시스템 개발을 위하여, 본 연구에서는 1)초고속/고밀도 금속소재 적층이 가능한 장비 제조기술, 2)고속 및 고평탄을 유지하기 위한 분말 도포 시스템, 3)잔류응력 최소화를 위한 공정개발 기술, 4)최적 산소농도 유지공급을 위한 질소-아르곤 가스 챔버 설계기술 등 금속프린팅 시스템 HW 기술을 소개하고자 한다. 본 연구를 위하여, 실제 환자 Data 14건 케이스를 기반으로 기성화된 임플란트와 관절환자 뼈 Data를 비교분석하였으며, 맞춤형 의료기기 개발 필요성을 확인하였다. 이를 위해 본 연구에서는 Co-Cr 계열 금속분말 소재를 활용하여 인공관절을 제작하고자 하였으며, 인공관절 중에서 하중의 무게를 가장 많이 받는 무릎관절 중 ‘피머’ 에 한하여 의료기기 부품기술개발을 진행하고자 하였다. 또한, 본 연구를 위하여, 인장강도, 굽힘강도, 비파괴검사 및 열처리 등의 후처리 공정을 통한 최종 맞춤형 의료기기를 제작하였다. 금속3D프린팅 시스템의 문제로 지적되어 온, 기공결함을 극복하기 위하여, 본 연구에서도 진공열처리를 통한 품질향상방안을 확인하였으며, 금속 3D프린팅 시스템의 품질향상에 대한 전반적인 내용을 서술하고자 하였다. 이를 위해, 본 연구에서는 ‘식약처 3D프린팅 가이드라인’을 적극 활용하여, 의료기기 인허가를 위한 기계적 물성 분석 및 선진 금속프린팅 시스템의 출력물과 비교 분석하였으며, 금속 3D프린팅 기술을 통한 다양한 산업으로의 적용을 실현하고자 하였다. 한편, 본 연구는 맞춤형 의료기기 제작을 위한 실제 환자 DB를 중심으로 인공 무릎관절을 실증적으로 개발-제작하는 사례연구를 수행하였다. 맞춤형 의료기기의 필요성에 대한 많은 의료분야 관심이 고조되면서 3차원 의료영상을 3D Data로 변환하는 실증연구가 주로 연구되어왔으나, 본 연구에서는 환자에서 추출된 의료영상을 3D Data로 변환하고 실제로 3D프린팅 기술을 통해 제작해봄으로서 구체적인 사례연구 및 개발방법론을 제시하였다. 특히, 본 연구는 치수정밀도 및 기계적강도 등의 실증 비교분석에서 맞춤형 의료기기로서의 적용가능성을 입증하였으며, 3D프린팅 맞춤형 의료기기 산업의 사업화를 위한 기초자료를 제공하고자 노력한 점에서 실무적 시사점이 있다고 볼 수 있다. 또한, 본 연구는 금속3D프린팅 품질향상을 위한 간결한 레이저 해칭패턴 적용을 제안 검증하였다. 이를 위하여, 다양한 레이저 해칭 패턴을 적용하여 출력물의 품질을 비교분석하였으며, 잔류응력을 최소화하는 방안을 제시하였다. 따라서, 본 연구는 금속출력물에 대한 잔류응력의 분포를 줄이기 위한 시스템적 방법으로 HW시스템의 고온 효과, SW시스템의 패턴효과를 확인함으로서, 본 연구는 금속3D프린팅 시스템의 품질향상을 위한 실무적, 실증적 연구 시사점을 제시하고 있다. In this study, we conducted to develop customized medical devices and the improvement of quality. For this purpose, we design and introduce metal 3D printing system for the manufacture of customized medical devices. In addition, we manufactured metal 3d printing system actually and analyzed metal printing performance. For this purpose, we introduce Metal 3D Printing HW System 1) Equipment Manufacturing technology for super high-speed / high-density metal material stacking, 2) Powder supply system with high-speed and high-flat maintenance, 3) Process development of the minimizing residual stress, and 4) Design of the Nitrogen-Argon gas chamber for optimal oxygen concentration maintenance. For this study, we compared 14 actual patient 3d data, and we confirmed the necessity of developing customized medical devices. And we developed the final customized medical devices through post-processes such as tensile strength, flexural strength, non-destructive testing, and heat treatment. In order to overcome porous defects, this study also confirmed the improvement of quality through vacuum heat treatment and describe the overall improvement of the quality of the metal 3D printing system.. On the other hand, this study conducted a case study on empirically developing and producing artificial knee joints, focusing on actual patient DBs for the production of customized medical devices. The growing up interest in the medical field, many other studies analyse to convert three-dimensional medical images into 3D data, In this study, we specifically studies the development methodologies which can convert medical images from patients into 3D data and we developed actually metal 3D printing technology. In particular, we demonstrated applicability of customized medical device through comparative analysis of dimensional accuracy and mechanical strength. And we make the effort to provide basic data for the commercialization, so we can say this article have practical implication. In addition, this study has verified the application of simple laser hatching pattern for improving metal 3D printing quality. For this purpose, we compared and analyzed the evidence of various laser hatch patterns and we found the method to minimize residual stress. Therefore, this study confirms the high temperature effect of the HW system and the pattern effect of the SW system as a systematic method to reduce the distribution of residual stress on metal printing output, and this study presents practical and empirical research implications for improving the quality of metal 3D printing system.

이벤트 발생 기반 자동 조절 센서 네트워크를 이용함 홈/빌딩 에너지 관리 시스템 설계 및 구현

전병주 중앙대학교 대학원 2013 국내석사

본 논문에서는, 홈/빌딩 에너지 관리 시스템의 무선 센서 네트워크의 라이프 타임을 연장하기 위하여 이벤트 발생 기반 자동 조절 센서 네트워크를 개발하였다. 또한 이를 이용하여 사용자의 퇴실에 따라 대기전력을 차단하는 에너지 관리 시스템을 개발하였다 이를 위하여 환경 정보를 수집할 수 있는 Interactive Control Monitoring System (ICMS)라는 센서 모듈과 사용 중인 디바이스들의 실시간 전력 소비량을 모니터링 하고 관리할 수 있는 Power Monitoring System (PMS)를 설계 하였다. 또한 무선 센서 네트워크의 라이프 타임을 연장하기 위하여 이벤트 발생 자동 조절 센서 네트워크(ESASN)를 제안하였다. 무선 센서 네트워크에서는 데이터 통신과 환경 정보 센싱 과정에서 많은 전력을 소모한다. ESASN은 장거리 데이터 송신에 사용되는 전력을 기존 전력을 이용하고 상황에 따라 sensing rate를 조절하여 센서 노드의 배터리의 전력을 효율적으로 소비한다. ICMS와 PMS를 이용하여 사용자의 퇴실에 따른 대기전력 차단시스템을 제안하였다. 논문에서 제시 하고 있는 시스템을 실제 물리 공간(중앙대학교 홈네트워크 연구 센터)에서 실험을 실행하였다. 본 연구의 결과물은 차세데 지능형 빌딩 에너지 관리 시스템 개발하는데 기여할 수 있다고 기대된다. This paper suggests event based self-adjusting sensor network (ESASN) to prolong the life-time of wireless sensor network (WSN) for home/building energy management system (EMS). Also, applying ESASN, this paper shows energy management system which cut off the standby power, depending on the existence of user. To implement ESASN and home/building EMS, we developed two end devices. ■ Interactive Control Monitoring System (ICMS) in order to collect inner environmental information. ■ Power Monitoring System (PMS) in order to monitor real-time energy consumption of electrical/household appliances. Also, we designed ESASN to prolong the life-time of WSN. In WSN, a lot of power is consumed for data transmission processing and sensing processing. ESASN reduces battery's power consumption by using adjusting sensing rate and energy efficiency multi-hop routing.

미세캡슐화 isoflavone을 첨가한 우유의 실험동물에 대한 골다공증 개선 효과

전병주 세종대학교 대학원 2007 국내박사

This study was designed to develop the functional milk for preventing and curing the osteoporotic condition. Initially, water-soluble isoflavone which plays a role of estrogen was microencapsulated and it was optimized. As a next step, β-galactosidase which may converse isoflavone glycoside to aglycone form was then microencapsulated and it was done for finding variations of digestion, absorption efficiency and biological effects in vitro study. Finally, animal test was conducted to find the effect of the isoflavone for osteoporosis, and the results of this study are as follows : The first part of this research was the microencapsulation of water-soluble isoflavone and applying into milk. Coating material was medium-chain triglyceride (MCT) and core material was water-soluble isoflavone. The microencapsulation efficiency was 70.2% when the ratio of coating material to core material was 15 : 1. The isoflavone release from microcapsules was 8% at 4 ℃ for 3 day storage. In sensory analysis, the scores of bitterness, astringency, and off-taste in encapsulated isoflavone-added milk were slight different from those in uncapsulated isoflavone-added milk, but not significantly different. In vitro study, microcapsuales of water-soluble isoflavone in simulated gastric fluid at the range of 2 to 5 pHs were released 4.0-9.3%, however, in simulated intestinal fluid at pH 8, 87.6% of isoflavone was released from capsules at 40 min incubation time. Therefore, it was confirmed the fact that MCT is acceptable for a coating material in the microencapsulation of water-soluble isoflavone for application into milk. The second part of the research was designed to find the optimum conditions for conversion of isoflavone glycoside to aglycone form by β-galactosidase, and the optimum conditions for isoflavone or β-galactosidase microencapsulation, and to examine the release efficiency of microcapsules in vitro. Three different kinds of the enzyme were tested and the optimum conditions for enzyme concentration, incubation time, temperature and pH were determined. Before applying the enzyme, isoflavone contained 89.5% of glycoside including daidzin, glycitin and genistin, and only 10.5% of aglycone including daidzein, glycitein and genistein. Among the enzymes, 35% of isoflavone hydrolysis, which was the highest rate, to aglycone was found when 3 unit/g Fungal Lactase (Amano Enzyme) was added. During 5 hr incubation, conversion of glycoside to aglycone increased dramatically from initial (0) to 1 hr, and plauteaued thereafter. And higher incubation temperature resulted in higher rate of hydrolysis along with greater loss of isoflavone mass. Therefore, body temperature (37 °C) could be adequate condition for isoflavone conversion, which 44.9% of hydrolysis with less than 10% mass loss. As expected, higher amount of aglycone was produced at pH 7, compared with those at other pHs. In addition to, coating materials were either medium-chain triacylglycerol (MCT) or polyglycerol monostearate (PGMS) for microencapsulation. The highest rate of microencapsulation was found at 15 : 1 (w/w) ratio of MCT to isoflavone or β-galactosidase as 70.2 or 75.4%, respectively. When PGMS was used as coating material, 91.5% β-galactosidase was microencapsulated with 15 : 1 mixture (w/w). In vitro study, less than 6.3 - 9.3% of isoflavone was released in simulated gastric fluid (pH 2, 3, 4 and 5) during 1 hour incubation. Comparatively, isoflavone release increased dramatically to 87.8% at pH 8 for 1 hour in simulated intestinal fluid and maintained thereafter. The release of β-galactosidase showed a similar trend to that of isoflavone. It was appeared in the range of 12.3 to 15.2% at pH 2-5, however, increased significantly to 80.6% as the highest value at pH 8. Among the released isoflavones, 53.5% was converted into aglycone form of isoflavone at pH 8 for 3 hour incubation. Therefore, the optimum conditions for isoflavone hydrolysis by β-galactosidase were 37 °C, pH 7 and 3 hr for incubation with 3 unit/g Fungal Lactase (Amano Lactase), and total average amount of produced aglycone was in the range of 40 to 47%. Moreover, isoflavone and β-galactosidase could be microencapsulated with fatty acid ester and effectively released in vitro condition. Finally, animal tests were conducted to investigate effects of microencapsulated water-soluble isoflavone and/or calcium and vitamin supplementation in milk on bone metabolism for the third part of the research. Thirty Sprague-Dawley rats of 6 week-old were divided into 2 groups (sham-operated and ovariectomized) and ovariectomized group was subdivided into 4 subgroups: 1) Sham, sham-operated and fed diet without supplement, 2) OVX, ovariectomized and fed diet without supplement, 3) OVX+Vit+Ca, ovariectomized and fed calcium and vitamin D and K supplements added, 4) OVX+Iso, ovariectomized and fed microencapsulated isoflavone added diet, and 5) OVX+Iso+Vit+Ca, ovariectomized and fed microencapsulated isoflavone, calcium, and vitamin D and K supplements added. Above supplements were consumed by dissolving in 1 mL milk. After 19 wk feeding, body weight gain and food intake efficiency ratio were significantly lower in Sham group than those in 4 OVX groups (p < 0.05). The lengths of femur and tibia were not significantly different among all groups, however, femoral weight was slightly but not significantly higher in OVX groups supplemented with isoflavone and/or calcium, vitamin D and K. In blood analysis, the ratio of BALP (bone alkaline phosphatase) to TALP (total alkaline phosphatase) concentration was the highest in OVX group (70.7%) and was the lowest in OVX+Iso+Vit+Ca group (57.4%) which was supplemented with isoflavone, calcium, vitamin D and K. In addition, serum osteocalcin was the highest in OVX+Iso+Vit+Ca but not significantly different among OVX groups (p > 0.05). Serum calcium was higher in Sham group and OVX+Iso+Vit+Ca group such as 11.6 and 11.7 m

Bearing Incipient Fault Detection, Diagnosis, and Unsupervised Prognosis with Failure Thresholding

전병주 서울대학교 대학원 2018 국내석사

Bearings are core components in rotating machines. Thus, early detection of faults and accurate prediction of a machine’s health state is highly desirable throughout the total lifecycle of a bearing. Rolling element bearing failure is one of the critical causes of breakdowns in rotating machinery; these types of failures are common in mechanical systems as well. Such failures can be catastrophic and can result in costly downtime. Particularly in industrial fields, minimization of downtime is critical. Thus, health monitoring of rotating machinery during operation is the focus of significant research interest. Accurate bearing health prediction is needed for these settings. There remains a need for health state prediction that can be accomplished in real-time, without future data. Therefore, a data-driven and real-time algorithm for bearing health monitoring is suggested in this thesis. The research objectives pursued to improve the bearing PHM framework include 1) full-time health monitoring, 2) definition of a failure threshold for rolling elements in general bearings, and 3) life prediction in real-time and in unsupervised situations. To classify the health state of bearings for detection of incipient faults and fault points, the Mahalanobis Distance is applied. For life prediction, previous researchers have experienced severe problems, particularly when the life prediction required analytic assumptions as a prerequisite, for example, those emerged at Particle Filters. To solve this problem, the research outlined in this paper suggests a new model and a threshold decision method that enables prediction of the Remaining Useful Life in real time (i.e., in unsupervised situations). This thesis is organized as follows. Section 1 provides an introduction, including the research motivation and an overview of the research objectives. Next, in Section 2, methodologies for detection of incipient anomalies, fault diagnosis, and failure prognosis are explained, along with a suggested definition and a trend projection model. Then, Sections 3 and 4 validate the suggested threshold and model using data acquired from Schaeffler Korea and Seoul National University, respectively. Finally, Chapter 5 concludes this thesis with a summary of the research contributions and suggestions for future work.

노인의 사회적 배제 특성, 주거 점유형태가 우울 및 생활만족도에 미치는 영향

전병주 충북대학교 2014 국내박사

As Korea's aging rapidly proceeds in stark contrast to other countries, diverse problems have been occurring at individual level as well as national level. The older adults are exposed to many risks which end up resulting in high level of stress, mental health problems, inadequate income maintenance, insufficient social networking, and quite low level of overall life satisfaction. In fact, Korea shows the highest elderly poverty rate and suicide rate among the OECD countries. Since it is difficult to explain various hardship and vulnerabilities which older adults are experiencing by a single factor, it is keenly necessary to have multidimensional investigations of the lives of older adults and to pay great attention to the concept of social exclusion. Meanwhile, older adults have limitations in daily activities due to the poor physical functions, so their area of activities are often constrained to housing. This is why we need to focus on the importance of residence. Although housing problems have a considerable influence on the lives of older adults, there is a lack of academic research on this issue. This study aimed to review the negative influence of multiple exclusion and housing tenure type on depression and life satisfaction, and investigate the potential mitigation effect of social network both on depression and life satisfaction. A total of 4,013 people aged 65 and over were selected as a sample out of the 3rd wave respondents of 2010 Korean Longitudinal Study of Aging. Because older adults are not a homogeneous population, customized policy and differentiated intervention need to be applied based on their intra-specific difference such as marital status and employment status. Divided into four sub-groups by marital status and employment status, relative effects of social exclusion, housing tenure type, and social networks on the depression and life satisfaction of older adults are examined. The main findings are as follows: First, the social exclusion score was 3.5(ranged from 0 to 9) for the entire sample, the single and the unemployed groups showed higher scores. The Married and employed groups showed the higher level of home-ownership. The level of social networks turned out to be 6.3(ranged from 0 to 10), with higher score for the married and employed groups. Second, the level of depression of the total sample was 4.4(ranged from 0 to 10) with higher score for the non-married or the unemployed. Level of life satisfaction showed 57.0(ranged from 0 to 100), with higher levels for the married or the employed groups. Third, social exclusion and social networks were found to be statistically significant variables on depression, while housing tenure type was not. Social exclusion, housing tenure type, and social networks are all verified to have influence on life satisfaction. Fourth, the buffering effect of social network was not proven to be significant for the relationship between independent variables and depression, but significant only for the mid-level depression group. This finding implied that although the negative impact of social exclusion was consistent, the buffering role of social network cannot be ignored, rather should be highlighted. In this study, in the relationship between social exclusion, housing tenure type and life satisfaction, additional explanatory power(△R2) of social network was proven large; the negative influence of the social exclusion and housing tenure type also consistently decreased which indicated a buffering role of the social networks. The contribution of this study is to provide evidence-based results for the practical policy directions for the older adults, focusing on potential buffering nature of social network. Particularly, this study used a composite variable including multiple dimensions of social exclusion, compared to other studies which separately used each domain of social exclusion. This will, I hope, promote better understanding of the older adults' complexity in social exclusion experience. Housing-related problems of older adults, which have not been well studied in the previous research, were examined based on the fact that home-ownership is highly aspired by all Koreans, and the fact that housing is important as one of the basics of independent living in local community lives. Since the negative effect of social exclusion and the potential buffering role of social network were proven to be exist, several proper measures should be taken to relieve older adults' depression and low life satisfaction, especially taking full advantage of social networks.

자동차 블로워 모터 불량 검출을 위한 인공지능 기반의 CNN 검사 시스템 개발

전병주 경남대학교 대학원 2025 국내석사

기존의 머신 비전 기반 불량 검출 방법은 정형화된 작업에는 효과적이나 비정형 결함 검출에는 한계가 있다. 이를 해결하기 위해 본 연구에서는 딥러닝을 활용한 자동차 블로워 모터 결함 검출 시스템을 제안한다. Inception, Xception, VGG19, ResNet 아키텍처를 기반으로 한 CNN 모델의 성능을 평가하고, 4개의 모델을 결합한 소프트 보팅 앙상블 기법을 적용하여 성능을 향상시켰다. 블로워 모터 이미지 데이터에 데이터 증강 기법을 적용하여 모델의 일반화를 강화하였으며, 테스트 결과 앙상블 모델은 단일 CNN 모델 대비 우수한 정확도와 일관된 결함 검출 성능을 달성하였다. Conventional machine vision-based defect detection methods are effective for standardized tasks but have limitations in detecting non-structured defects. To address this issue, this study proposes a deep learning-based defect detection system for automotive blower motors. The performance of CNN models, including Inception, Xception, VGG19, and ResNet architectures, was evaluated, and a soft voting ensemble technique combining these four models was applied to improve detection performance. Data augmentation techniques were applied to blower motor image data to enhance model generalization. Test results demonstrated that the ensemble model achieved superior accuracy and consistent defect detection performance compared to individual CNN models.

유전자 알고리즘을 활용한 녹색건축인증용 경제적 자재선정 모델 개발

전병주 경북대학교 대학원 2020 국내석사

한국 정부는 ‘2030 국가 온실가스 감축 목표 달성을 위한 기본 로드맵’에서 2030년까지 배출전망치 대비 37% 감축을 제시하였다. 또한, 환경부에서는 건물부문의 온실가스 배출량을 2030년까지 배출전망치 대비 32.7% 감축을 목표로 제시하였다. 이러한 목표를 달성하기 위해, 국토교통부는 녹색건축물 기본계획을 수립하여 녹색건축인증의 보급에 힘썼다. 이와 같은 노력에 힘입어 녹색건축인증실적은 매년 꾸준한 증가세를 보이며, 사회적 관심도 커지고 있다. 하지만 고무적인 성과에도 불구하고 녹색건축인증은 현재 대행사를 통해 인증평가를 대행하는 과정에서 보안 등을 이유로 자재안의 자재관리 및 시공성과 공사비에 대한 고려가 부족하며, 절차의 복잡성 때문에 인증과정에 소요되는 시간이 증가한다. 따라서, 본 연구에서는 이러한 문제들을 해결하기 위하여, 유전자 알고리즘을 활용하여, 점수와 공사비를 함께 고려할 수 있는 자재대안 도출을 위한 모델을 개발하고 검증 및 보완하였다. 모델의 개발에는 자재대안을 만들기 위한 데이터베이스와 만들어진 자재대안의 평가 자동화가 필요하다. 모델 자재대안을 구성하기 위한 데이터베이스는 기존 인증자재 목록 중 녹색건축에 관련된 자재목록을 선별하여 인증과 비용정보가 포함된 3,688개의 자재목록을 구성하였다. 자재대안의 평가 자동화에는 알고리즘화한 점수산정 및 비용산출 프로세스를 활용하였다. 이를 유전자 알고리즘과 연계하여 새로운 자재대안을 만들고, 세대를 거치며 개선할 수 있도록 하였다. 개발된 모델은 건축물의 연면적과 기본 자재수량, 요구점수 세가지 정보을 기반으로 최적의 자재대안을 도출하였다. 네가지 사례에 대해 모델의 검증결과 평균 44.75가지의 자재를 사용하여, 컨설팅 자료에 비해 평균 36.5%가량의 비용절감을 달성하여 시공성에 큰 영향을 미치지 않으면서도 공사비 절감을 달성하는 것으로 평가되었다. 본 연구에서 개발한 모델을 통해 경재적 자재대안을 도출하여 시공성과 경제성을 함께 고려한 자재대안 선정에 도움이 될것으로 기대된다. The Korean government had proposed a 37% reduction over the BAU (business as usual) in the '2030 Basic Road-map on National Greenhouse Gas Mitigation'. Ministry of Environment declared a 32.7% reduction in greenhouse gas emissions from construction by 2030. To achieve this goal, the Ministry of Land, Infrastructure, and Transport established a system called Green Standard for Energy and Environmental Design (G-SEED) to secure the environmental efficiency of buildings; which is a basic plan for the Green Building. Social interest in G-SEED is growing, but construction engineers often receive G-SEED certifications through consulting companies. In the process, data sharing and business linkage are not smoothly performed due to security reasons. So it is difficult to secure economic efficiency and constructability. In this study, an economic feasibility model was developed using the GA (Genetic Algorithm) methodology, which considers both the acquisition of the evaluation score on materials and resources. Also, the model was verified and supplemented. The development of the model requires a database to create a material alternative and automate the evaluation of the created material alternative. A database of 3,688 material was used to select a material list that related to green construction from the list of certified materials. Algorithmic scoring and cost calculation processes were used to automate the evaluation of material alternatives. By linking it with the genetic algorithm, new material alternatives were created and improved over generations. The developed model derives the optimal material alternative based on three information: the total building floor area, the material quantity, and the required score. The result of four case studies used to verify the model verification revealed an average cost reduction of 36.5% compared to consulting data using 44.75 types of materials. It is estimated that the reduction of the construction cost was achieved without significantly affecting constructability. It is expected that the model developed in this study will help to select a material alternative considering the construction and economic feasibility by deriving a better material alternative.

건설도급계약에 있어 수급인의 하자담보책임

전병주 충북대학교 2009 국내석사

Processes in construction works are complex with diversified variables based on situations and new skills, requiring experiences, knowledge, and efforts of various people. After basic subjects for construction including the location and size of land, the use and shape of a building, and cost for construction are examined, practical design and consequent construction are followed. All these processes may be progressed by those who are employed by the party concerned, but in many cases part of or the whole construction are done by contractors due to insufficiency in professional knowledge and skills. A contract is an agreement with which a party promises to complete a work and the other party promises to pay for the results of the work. The construction and transportation industries are representatively engaged in such contracts, but the main subject of regulations on the contracts in the Civil Law is construction contracts because the contracts on transportation are detailedly regulated in the Commercial Law due to its significance and particularity. Practically, however, the principles in the Civil Law are being considerably altered to be applied in construction contracts. Although construction contracts are included in contract by legal properties, they are considerably different from pure contract regulated by the Civil Law and various interpretations are possible according to construction works due to the significant differences in laws applied on the basis of scales of construction and those who perform a project. In Korea, the security for defects of contractors in construction contracts is provided in Clause 667 of the Civil Law, but various problems are raised because of legal insufficiency and incompleteness. The author of this study, in order to find solutions to such problems, examined not only cases of legislation and legal cases of major nations but domestic theories, legal cases, and laws and ordinances. Also, the author detected suggestions in problem solution, presented new guide in interpretation, searched legislative approaches, by reviewing foreign systems of security for defects. On the purpose of this study, this study is divided into five chapters as follows. In the first chapter the purpose, scope, and methods of this study are presented generally, and in the second chapter, the author will compare and consider the foreign cases on security of defects of contractors in building contracts from both Anglo-American Laws and Romano-Germanic laws to identify the origins and changes to date of security of defects of contractors. Chapter 3 includes concrete examinations on building contracts and security for defects of contractors. First, the author will review principal contents of the Construction Industry Standard Act related to realization of building contracts, and consider legal appraisement on information presentation and solicitation in negotiation stage before contract establishment that are being discussed recently in the context of consumer protection. Second, the factors of establishing security for defects of contractors in the processes of relevant construction works are searched, and the contents of security for defects regulated in the Civil Law, the Remuneration Right of Maintenance Reduction, and the Remuneration Right of Solatium are reviewed from literature and cases of German and Japan. Also, the contents on individual security for defects in the Construction Industry Standard Act special laws and special laws including the Act on Ownership and Management of Collective Building and insufficiency in such laws are searched and reviewed on revisions of the laws. Third, the housing quality control system of France, England, and Japan that is managed as a practical system of security for defects and, in particular, compulsory building liability insurance scheme of France are examined and measures of introducing such systems to Korea. In Chapter 4, the author will investigate institutional and operational problems including prolongation of period of security for defects and insufficiency in diagnosing facilities on defects related to security of defects of contractors in the existing building contracts, and search reasonable measures to improve through law readjustment and introduction of new systems. Lastly in Chapter 5, the contents of this study are summarized on the whole to present improvements of problems in security of defects of contractors in the existing building contracts and developments in further subjects.