• 대한기계학회논문집B
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• 제22권1호
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• pp.61-69
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• 1998

Vapor Axial Deposition (VAD), one of optical fiber preform fabrication processes, is performed by deposition of submicron-size silica particles that are synthesized by combustion of raw chemical materials. In this study, flow field is assumed to be a forced uniform flow perpendicularly impinging on a rotating disk. Similarity solutions obtained in our previous study are utilized to solve the particle transport equation. The particles are approximated to be in a polydisperse state that satisfies a lognormal size distribution. A moment model is used in order to predict distributions of particle number density and size simultaneously. Deposition of the particles on the disk is examined considering convection, Brownian diffusion, thermophoresis, and coagulation with variations of the forced flow velocity and the disk rotating velocity. The deposition rate and the efficiency directly increase as the flow velocity increases, resulting from that the increase of the forced flow velocity causes thinner thermal and diffusion boundary layer thicknesses and thus causes the increase of thermophoretic drift and Brownian diffusion of the particles toward the disk. However, the increase of the disk rotating speed does not result in the direct increase of the deposition rate and the deposition efficiency. Slower flow velocity causes extension of the time scale for coagulation and thus yields larger mean particle size and its geometric standard deviation at the deposition surface. In the case of coagulation starting farther from the deposition surface, coagulation effects increases, resulting in the increase of the particle size and the decrease of the deposition rate at the surface.

• 한국의사학회지
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• 제19권2호
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• pp.29-47
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• 2006

Because the size of population was directly related to the power of the nation in the Chosun Dynasty, various efforts were exerted to maintain the size stable and the keys to the efforts were a high birth rate and a low death rate. However, in addition to wars, epidemic diseases had an enormous effect on the death rate. Particularly during the mid Chosun Dynasty, epidemic diseases were more prevalent than ever due to the abnormal climate called the little ice age. To cope with them, the government executed several medical relief policies and published medical books. In Chinese epidemiology, infectious diseases mean sicknesses caused by hot weather, but in Korean epidemiology, they indicate large-scale infectious sicknesses caused by both hot and cold weather. Therefore, as treatment methods for diseases from the cold were not applicable to the pathology of epidemic diseases, China developed separate epidemiology. In Korea, however, the main concern was how to prevent epidemic diseases, whether from hot or cold weather, that drove many lives into death. The characteristics of Korean epidemiology are as follows. First, whenever epidemic diseases were prevalent, in order to cope with them, translated medical books were promptly published including Ganibyeokonbang, Bunmunonyeokihaebang, Sinchanbyeokonbang, Byeokyeoksinbang and Byeokonsinbang. Second, those books were annotated in Korean so that people could read easily and accurately. Third, as an extension of the Hyangyak movement from the late Koryo Dynasty, Danbang was used a lot to treat and prevent epidemic diseases with less financial burden, and things obtainable easily according to individuals' situation were mentioned for anybody to overcome the emergent situation of epidemic diseases. Fourth, methods for praying to God were suggested for practitioners to work with sincere spirit and to keep themselves from epidemic diseases.

• 화훼연구
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• 제19권2호
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• pp.119-125
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• 2011

창포는 한국에 자생하는 수생식물로 약용뿐만 아니라 phytoremediation과 수질정화 식물로도 알려져 있다. 본 연구에서는 창포의 기내 식물체에 다양한 선량(20-500 Gy)의 감마선을 조사하여, 방사선의 효과 및 감수성을 확인하기 위해 2달후 생존율, 신초형성율 및 생장율을 측정하였다. 생존율과 신초형성율은 감마선 선량이 증가할수록 현저하게 감소하였다. 기내에서 저선량을 조사한 식물체의 생장율은 대조구에 비해 오히려 증가하였으나, 250 Gy 이상에서는 생장이 멈추거나 유의하게 감소하였으며, 반치사선량($LD_{50}$)은 240 Gy로 다른 식물종의 $LD_{50}$보다 훨씬 높은 선량이었다. 창포에서 저선량을 조사하였을 때 생장율이 증가하는 방사선호메시스(radiation hormesis) 효과를 확인하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제32권4호
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• pp.519-526
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• 2019

Objective: We determined the risk factors limiting first service conception (FSC) rate in dairy cows and their economic impact. Methods: Data were collected from 790 lactations regarding cow parity, peri- and postpartum disorders, body condition score (BCS), reproductive performance, and expenses associated with reproductive management (treatment, culling, and others). Initially, we identified the risk factors limiting FSC rate in dairy cows. Various biological and environmental factors, such as herd, cow parity, BCS at 1 month postpartum and first artificial insemination (AI), resumption of cyclicity within 1 month of calving, year, AI season, insemination at detected estrus or timed AI, peri- and postpartum disorders, and calving to first AI interval, were evaluated. Next, we evaluated the economic impact of the success or failure of FSC by comparing the expense associated with reproductive management until conception between cows that did or did not conceive at their first service. Results: Cows with BCS <3.0 had a lower probability of conceiving at first insemination (odds ratio [OR] = 0.64, p<0.05) than cows with $BCS{\geq}3.0$. Cows inseminated during summer were less likely to conceive (OR = 0.44, p<0.001) than cows inseminated during spring. Cows with peri- or postpartum disorders were less likely to conceive (OR = 0.55, p<0.001) than cows without disorders. Survival curves generated using MedCalc showed an 81 day extension in the mean interval between calving and conception in cows that failed to conceive over those that did conceive at first insemination. Cows failing conceive required additional expenditure on reproductive treatment ($55.40) and other management ($567.00) than cows that conceived at first insemination. Conclusion: Lower BCS, hot weather at first insemination, and peri- and postpartum disorders are risk factors limiting FSC, which result in an economic loss of $622.40 per dairy cow.

• 대한두경부종양학회지
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• 제37권2호
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• pp.25-31
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• 2021

Background/Objectives: Although thyroid lobectomy recently is considered as sufficient for low-risk papillary thyroid carcinoma (PTC), completion thyroidectomy is required due to the insufficiency of the preoperative evaluation. The aim of this study was to investigate recurrence rate and disease free survival depending on the gross extrathyroidal extension (gETE) or the number of metastatic lymph node identified in patients with PTC. Materials & Methods: We assessed 3373 patients with PTC who underwent lobectomy at Seoul St. Mary's Hospital (Seoul, Korea) between January 2009 and December 2014. Clinicopathological characteristics and long-term surgical outcomes were retrospectively analyzed through complete chart reviews. The mean follow-up duration was 97.1 ± 21.4 months. Results: The rate of recurrence was higher in gETE group (1.8% vs. 6.0%, p=0.004), leading to decreased disease free survival in Kaplan-Meier analysis (log-rank p<0.001). N1 group (n=1389) was analyzed into two groups whether the number of positive nodes is more than 5 or less. For the group of the more metastatic nodes, the recurrence rate higher compared to the other group (3.0% vs. 9.3%, p<0.001). DFS was longer in the group that had lesser metastatic nodes (log-rank p<0.001). However, in terms of N1 group over 1cm (n=492), No statistical difference was observed according to the number of positive lymph nodes (4.5% vs. 9.1%, p=0.092) Conclusion: When it comes to node positive PTC, Despite the number of positive lymph nodes was over 5, follow-up with no further surgery can be an option.

• 여성건강간호학회지
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• 제10권3호
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• pp.244-251
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• 2004

Purposes: This study was to examine the effects of postpartum exercise on pressure of the pelvic muscle contraction, body composition and physical fitness of postpartum mothers. Method: A nonequivalent pre-test, post-test control group study was conducted. Fifty-two postpartum mothers(experimental group, 26; control group, 26) admitted to a postpartum ward in a Busan mother-baby clinic were recruited. Data was analyzed using mean, $x^2$-test, and t-test by SPSS 10.0. Result: Body fat mass(t=-3.196. p= .002), body fat rate (t=-3.831, p= .000), and fat distribution(t=-3.026, p= .004) of body composition increased significantly in the experimental group after the postpartum exercise as compared with the control group. After an 8 week exercise program, the pressure of the pelvic muscle contraction in the experimental group was significantly higher than in the control group(t=3.329, p=.002). In the change of physical fitness, grip strength of the hand, back muscle strength, and trunk flexion forward were not significantly changed, but trunk backward extension in the experimental group significantly increased(t=1.950, p=.050). Conclusion: Postpartum exercise affects pelvic muscle contraction, body composition, and physical fitness of the postpartum mother.

• Journal of Communications and Networks
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• 제17권1호
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• pp.47-57
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• 2015

With the ever growing demand of data applications, the joint macro-relay networks are emerging as a promising heterogeneous deployment to provide coverage extension and throughput enhancement. However, the current cellular networks are usually designed to be performance-oriented without enough considerations on the traffic variation, causing substantial energy waste. In this paper, we consider a joint macro-relay network with densely deployed relay stations (RSs), where the traffic load varies in both time and spatial domains. An energy-efficient scheme is proposed to dynamically adjust the RS working modes (active or sleeping) according to the traffic variations, which is called traffic-aware relay sleep control (TRSC). To evaluate the performance of TRSC,we establish an analytical model using stochastic geometry theory and derive explicit expressions of coverage probability, mean achievable rate and network energy efficiency (NEE). Simulation results demonstrate that the derived analytic results are reasonable and the proposed TRSC can significantly improve the NEE when the network traffic varies dynamically.

• 자원환경지질
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• 제46권4호
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• pp.313-327
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• 2013

본 연구에서는 캐나다 아사바스카 지역의 맥머레이층에 대한 3차원 지구통계 모사를 실시하였으며 모사 결과를 바탕으로 심부지열회수방법을 통한 경제적 산출 가능 지역을 가늠하고자 하였다. 비투멘의 효율적인 생산을 위하여 SAGD 공법의 최적 입지를 선정하는데 있어 스팀챔버의 충분한 수직적 연장성을 확보하는 것은 중요한 사항이다. 연구지역에서 획득한 110개의 시추공 자료에 대하여 마르코프 전이 확률 기반의 분석을 실시하였으며 이를 바탕으로 맥머레이층 구성 암상에 대한 추계론적 예측을 실시하였다. 추계론적 모사를 통하여 획득한 다중재현을 기반으로 앙상블 확률 분포도를 제작하였으며 이는 각 암상이 분포 할 수 있는 포텐셜을 보여준다. 앙상블 확률 분포도를 이용하여 투수성 퇴적층(역질 퇴적층 및 사질 퇴적층)에 대한 누적 층후도를 구성하였으며 이를 바탕으로 SAGD 공법이 적용될 수 있는 최적 입지를 선정하였다. SAGD 최적 입지 선정을 위한 추가적인 분석을 실시하기 위하여 전이율을 바탕으로 한 단일 퇴적층의 평균적인 수직 및 수평적 연장성을 산정하였다. 투수성 퇴적층의 평균적인 수직적 연장성은 대체로 투수성 퇴적층에 대한 누적층후도 분포도와 유사한 분포 양상을 보이나 일부 누적 층후가 큰 위치에서 유사하지 않은 양상을 보인다. 이는 누적 층후도와 평균적인 수직적 연장성 분포 양상이 유사하지 않은 지역은 투수성 퇴적층과 다른 암상과의 교호성은 매우 크나 투수성 퇴적층의 수직적인 연장성은 좋지 않음을 의미한다. 따라서 누적층후도 뿐 만 아니라 투수성 퇴적층의 수직적 연장성 또한 충분히 고려하였을 때 건전한 SAGD 최적 입지를 선정하는데 충분히 신뢰성 있는 결론을 도출 할 것으로 판단된다.

• 대한두경부종양학회지
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• 제20권2호
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• pp.123-127
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• 2004

Objectives: The tall cell variant is an uncommon variant and has been known as more aggressive form of papillary thyroid carcinoma (PTC). Owing to the rarity of these thyroid cancers, their clinical behavior remains incompletely understood. To elucidate the clinicopathologic characteristics of tall cell variant, we retrospectively reviewed our surgical experience of patients with tall cell variant. Methods: Between August 1993 and July 2004, a total of 11 consecutive patients who were pathologically diagnosed with tall cell variant of papillary thyroid carcinoma were enrolled in this study. All patients underwent total (8 cases) or subtotal thyroidectomy (3 cases) with central compartment node dissections. The lateral neck dissection was added in 6 patients. After the operation, neck ultrasound and serum thyroglobulin were checked regularly during the follow-up period. Results: The mean age of the patients was 56.6years (range, 30-74years) at the time of diagnosis. 3 patients were men, and 8 were women. The mean diameter of tumor was 3.7cm(range, 1.5-6.0cm), and 6 patients had lateral neck node metastasis. Extrathyroidal extension was seen in 5 patients (45%). Loco-regional recurrence was found in 2 patients (18%), and distant metastasis in 1 patient (9%). The 5-year disease free survival rate was 68%. Conclusion: The tall cell variant of papillary thyroid carcinoma is an uncommon disease. Clinicopathologic feature and prognosis of this disease show more aggressive behaviors than ordinary papillary thyroid carcinoma. More aggressive treatment and close follow-up should be undertaken in the tall cell variant of papillary thyroid carcinoma.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1997년도 추계학술대회논문집
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• pp.406-413
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• 1997

근전도(EMG:Electromyogram)를 사용하여 국부 근육 피로(Localized Muscle Fatigue)를 정량화으로 분석 하기 위해 널리 이용되고 있는 AR(Autoregressive)모델의 1차 계수, RMS(Root Mean Square), ZCR(Zero Crossing Rate), MPF(Mean Power Frequency), MF(Median Frequency)를 선택하여, 근육이 발휘하는 힘과 시간의 흐름에 따라 근육 피로의 정도를 민감하게 나타내는 매개변수를 규명하였다. 피실험자 10명의 좌우 척추세움근(Erector Spinae Muscle)을 대상으로 등장수축(Sustained Isometric Contraction)조건에서 허리의 신전(Extension)운동을 실시하였다. 이때 발휘해야 하는 힘의 수준은 15%, 30%, 45%, 60%, 75% MVC 로 정하였고 각 수준마다 20초 동안 근전도를 측정하 였다. 데이터 분석은 총20초 구간의 근전도를 0.5초 간격으로 나누어 매개변수들을 각각 구하고 분석을 실시하였다. 시간의 흐름에 대한 피로도 분석 결과, AR 모델의 1차 계수와 MPF가 유의한 차이를 보였으며, 낮은 수준의 %MVC에서는 AR 계수가, 높은 수준에서는 MPF가 민감한 반응 결과를 나타냈다. 그리고 근육이 발휘하는 힘의 정도를 분석하기 위해 주로 사용되고 있는 RMS 보다는 더 AR 계수가 모든 수준에서 뚜렷하게 차이를 보인 것이 확인되었다. 따라서 AR 모델의 1차 계수가 근육의 피로 정도와 힘의 수준을 다른 매개변수에 비해 더욱 민감하게 구별함이 입증되었다. 이러한 결과는 다른 분야에서도 근육 피로를 정량적으로 측정하는데 사용될 수 있을 것으로 생각되며, 개인적 변이도를 고려한 확률 기법을 사용한다면 보다 정확한 근전도 분석이 이루어질 것으로 기대된다.있음을 알 수 있었다. 사료된다.의 결과는 자전거 에르고노미터의 결과가 트레드밀의 결과에 87.60%정도 나타났다.음을 관찰하였다. 특히 vitamin C와 E의 병용투여는 상승적으로 적용하여 간세포손상을 더욱 억제시킴을 알 수 있었다.mance and on TFP(Total Factor Productivity) growth which is a pure measure of firm performance. To utilize the advantage of panel data, FEM(Fixed Effect Model) and REM(Random Effect Model) were used. The empirical result shows that the entropy index as a measurement of inter-business relatedness is not significant but technological relatedness index is significant. OLS estimates on pooled data were considerably different from FEM or REM estimates on panel data. By introducing interaction effect among the three variables for business portfolio properties, we obtained three findings. First, only VI (Vertical integration) has a significant positive correlation with ROS. Second, when using TFP growth as an dependent variable, both TR(Technological Relatedness) and f[ are signif