공기 포일 베어링으로 지지되는 터보 압축기의 공력 불안정성이 로터에 미치는 진동 영향

김태호,이용복,김창호,이남수,김광호,신유환,Kim, Tae-Ho,Lee, Yong-Bok,Kim, Chang-Ho,Lee, Nam-Soo,Kim, Kwang-Ho,Shin, You-Hwan 한국유체기계학회 2003 한국유체기계학회 논문집 Vol.6 No.2

An oil-free turbo-compressor supported by compliant foil bearings which remove oil-contamination by elimination of a conventional ball bearing and oil lubrication systems is presented. Turbo-compressor makes two individual air compressions with two impellers at a operating speed of 39,000 rpm. In this study, the rotordynamic effects caused by aerodynamic instability were investigated with variable mass flow rates. Correlations between frequencies of pressure fluctuation in two diffusers and those of excitation forces on rotor were clearly observed in an aerodynamic unsteady region. Thus, these results show that it is beneficial to design high-speed rotating turbomachinery by considering coupling effect between aerodynamic instability and rotordynamic force.

콘크리트 양생을 위한 열차진동 평가사례

김태호,김욱종,김효락,Kim, Tae-Ho,Kim, Ook-Jong,Kim, Hyo-Rak 한국공간구조학회 2011 한국공간구조학회지 Vol.11 No.2

2D 어레이 다이오드 검출기를 통한 IMRT 계산선량의 정확성 평가 및 효용성 연구

김태호,오승종,김민주,정원균,정진범,김재성,김시용,서태석,Kim, Tae-Ho,Oh, Seung-Jong,Kim, Min-Joo,Jung, Won-Gyun,Chung, Jin-Beom,Kim, Jae-Sung,Kim, Si-Yong,Suh, Tae-Suk 한국의학물리학회 2011 의학물리 Vol.22 No.2

2D 어레이 다이오드 검출기를 이용하여 전립선과 두경부 IMRT 환자(전립선 2사례, 두경부 2사례)를 대상으로 선량계산 격자 크기(calculation grid size)에 따른 계산선량 정확성(dose calculation accuracy)을 평가했으며, 그 결과를 바탕으로 2D 어레이 다이오드가 IMRT 계산선량과 조사선량 검증에 적합한지 여부를 확인했다. 치료계획장치(treatment planning system, TPS)에서 제공되는 4종류의 격자 크기(1.25 mm, 2.5 mm, 5 mm, 10 mm) 별로 계산된 선량과 2D 어레이 다이오드 검출기를 이용하여 얻어진 측정선량을 감마 분석방법을 이용, 비교하는 방식으로 실험을 진행하였으며, 선량분포의 변화 범위에 따른 정확성 변화 또한 확인했다. 3 mm/3%의 평가기준(acceptance criteria)을 적용한 감마 분석방법에서는 10 mm를 제외한 격자 크기 별 평균 통과율(pass rate)에 뚜렷한 차이를 확인할 수 없었으나, 평가기준을 3 mm/3%, 2mm/2%, 1 mm/1%로 세밀하게 적용하였을 경우, 1.25 mm를 제외한 격자크기의 통과율이 각각 5%와 20%, 31.53% 감소하는 것을 확인할 수 있었다. 격자 크기에 따른 선량계산시간은 1.25, 2.5, 5, 10 mm 격자 크기에서 각각 11.5, 4.77, 2.95, 1.5 min 소비됐으며 격자 크기가 2배 증가할수록 선량계산시간은 약 1/2로 감소되는 결과를 확인할 수 있었다. 또한 저경사도영역(low gradient area)과 고경사도영역(high gradient area)을 구분하여 격자 크기영향을 평가하였으며, 격자 크기가 계산선량 정확성에 미치는 효과는 low gradient area보다 high gradient area에서 더 크게 작용한다는 결과를 확인했다. 본 연구의 결과를 종합해 봤을 때 2.5 mm의 격자 크기로 선량계산을 수행하는 것이 계산선량 정확성과 계산시간 면에서 적절한 것으로 여겨지며, high gradient area에 있어서는 가능한 세밀한 격자크기(1.25 mm)를 적용할 것이 권장된다. 또한 이상의 결과가 기존 연구의 이론 및 필름을 이용한 측정과 동일함을 고려해 봤을 때 2D 어레이 다이오드 검출기가 IMRT 계산선량과 조사선량 검증에 적합함을 확인할 수 있었다. In this study, we evaluated the effect of grid size on dose calculation accuracy using 2 head & neck and 2 prostate IMRT cases and based on this study's findings, we also evaluated the efficiency of a 2D diode array detector for IMRT quality assurance. Dose distributions of four IMRT plan data were calculated at four calculation grid sizes (1.25, 2.5, 5, and 10 mm) and the calculated dose distributions were compared with measured dose distributions using 2D diode array detector. Although there was no obvious difference in pass rate of gamma analysis with 3 mm/3% acceptance criteria for the others except 10 mm grid size, we found that the pass rates of 2.5, 5 and 10 mm grid size were decreased 5%, 20% and 31.53% respectively according to the application of the fine acceptance criteria, 3 mm/3%, 2 mm/2% and 1 mm/1%. The calculation time were about 11.5 min, 4.77 min, 2.95 min, and 11.5 min at 1.25, 2.5, 5, and 10 mm, respectively and as the grid size increased to double, the calculation time decreased about one-half. The grid size effect was observed more clearly in the high gradient area than the low gradient area. In conclusion, 2.5 mm grid size is considered acceptable for most IMRT plans but at least in the high gradient area, 1.25 mm grid size is required to accurately predict the dose distribution. These results are exactly same as the precious studies' results and theory. So we confirmed that 2D array diode detector was suitable for the IMRT QA.

세계 최초 드롭형 거푸집 공법 개발을 통한 시공생산성 향상 및 환경친화적 공사수행 사례

김태호,김욱종,이도범,김한기,Kim, Tae-Ho,Kim, Uk-Jong,Lee, Do-Beom,Kim, Han-Gi 한국건설관리학회 2010 건설관리 : 한국건설관리학회 학회지 Vol.11 No.4

통화시장체계의 대체성 검정

김태호,Kim, Tae-Ho 한국데이터정보과학회 2011 한국데이터정보과학회지 Vol.22 No.1

PCS 3사의 동시 서비스가 제공되면서 유무선 통화 수요는 초기의 보완관계에서 대체관계로 전환되었고, 이후 유선 시외전화 시장은 이동전화에 의해 잠식되어 매출액이 매년 감소해 왔다. 본 연구에서는 통화시장의 변환기 동안 유선 시외전화 시장과 이동전화 시장 간 상호 역학관계를 분석하고, 이동통화의 확산이 과연 시외통화 매출 감소의 직접적인 요인이었나를 통계적으로 검정하였다. 검정결과는 이동전화 이용과 시외전화 매출 간 직접적 대체관계의 증거를 발견하기는 어려우며 일반적 인식과는 달리 초기의 보완관계가 상당기간 유지되었음을 입증해준다. After the launch of PCS in 1997, the mobile telephone industry has achieved a remarkable growth in market share and sales, and substituted for long-distance wire communication market. This study investigates the interrelationships between the two markets in transition and attempts to perform the statistical tests if the diffusion of mobile telephone was the direct factor for the reduction in sales of long-distance communication industry. The evidence of the direct substitution effect between the two markets is not likely to be found. Unlike the general expectations, the test result seems to prove the sustained initial complementary relation for awhile.

Direct Medical Costs for Patients with Type 2 Diabetes and Related Complications: A Prospective Cohort Study Based on the Korean National Diabetes Program

김태호,전기홍,Hae Jin Kim,Seung Jin Han,김대중,Jiyeong Kwak,김영설,우정택,박용수,남문석,백세현,안규정,이관우 대한의학회 2012 Journal of Korean medical science Vol.27 No.8

We analyzed the direct medical costs for Korean patients with type 2 diabetes according to the type of complications and the number of microvascular complications. We analyzed costs for type 2 diabetes and associated complications in 3,125 patients. These data were obtained from the Korean National Diabetes Program (KNDP), a large, ongoing,prospective cohort study that began in 2005. The cost data were prospectively collected,using an electronic database, for the KNDP cohort at six hospitals. The costs were analyzed according to complications for 1 yr from enrollment in the study. Among 3,125 patients,918 patients had no vascular complications; 1,883 had microvascular complications only;51 had macrovascular complications only; and 273 had both complications. The annual direct medical costs for a patient with only macrovascular, only microvascular, or both macrovascular and microvascular complications were 2.7, 1.5, and 2.0 times higher than the medical costs of patients without complications. Annual direct medical costs per patient increased with the number of microvascular complications in patients without macrovascular complications. The economic costs for type 2 diabetes are attributable largely to the management of microvascular and macrovascular complications. Proper management of diabetes and prevention of related complications are important for reducing medical costs.

시설원예농가의 재생에너지 적용가능성평가 -지열.태양광의 경제성 분석을 중심으로-

김태호,윤성이,Kim, Tae-Ho,Yoon, Sung-Yee 한국유기농업학회 2012 韓國有機農業學會誌 Vol.20 No.3

In this study, RPS system, one of the renewable energy support systems, is utilized for economic analysis of solar generation equipment and the fuel cost savings plan for controlled horticulture farms with high fuel-cost dependency and facility applicability were evaluated. On the exterior of the upper layer of glass greenhouse (9917$m^2$) of controlled horticulture farms using bunker C oil, half of the area (4958$m^2$) was utilized for theoretical installation and operation of 450kW-level solar power generator, and as the result, first, the effect of investment cost only of solar generation system was found to be quite excellent, but it was analyzed that there were limits to saving the fuel costs of the controlled horticulture farms. Second, when geothermal system was first introduced in the farm and solar system was additionally introduced, it was analyzed that the effect of introducing solar system was excellent. In order to apply such effects to the sites of farming, partial supplementation of RPS system which is being uniformly applied regardless of the purpose of renewable energy is necessary. When the subject of use directly install facilities where it is directly connected to national added-value such as food security created by the farming industry, it is necessary to introduce appropriate system that corresponds to such. Moreover, it was studied that the quick development of demonstrative complex that can practically evaluate the applicability of renewable energy in farming industry and interest and preparation of related institutions in financial support structure for its site application would lead to success.

120G/T톤급 대형기선 저인망어선(선미식) 건조에 즈음하여

김태호,Kim, Tae-Ho 선박안전기술공단 1980 漁船 Vol.5 No.-

건강관리코너 - 고혈압이야기

김태호,Kim, Tae-Ho 한국화재보험협회 2004 防災와 保險 Vol.104 No.-

최근서구화된 식이 및 생활 습관과 급변하는 사회적 환경으로 인한 스트레스 증가 등으로 협심증, 심근경색, 뇌졸증 등의 심혈관 질환의 급격한 증가가 가장 중요한 한국인 성인 사망 원인으로 떠오르고 있다. 또한 국내 성인의 약 20~25%가 고혈압을 가지고 있는 것으로 조사되고 있는 현 시점에서 심혈관 질환의 중요한 요인인 고혈압에 대하여 간단히 살펴보기로 한다.

구조안전성 및 사용성을 위한 공장 진동 평가

김태호,김효락,Kim, Tae-Ho,Kim, Hyo-Rak 한국공간구조학회 2011 한국공간구조학회지 Vol.11 No.4