• Journal of Nutrition and Health
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• 제35권1호
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• pp.12-23
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• 2002

Gender differences in the effects of gonadectomy and high cholesterol diet on body weight and body cholesterol were investigated by using Sprague Dawley rats. Body weight, plasma and liver levels of cholesterol and triglyceride and platelet aggregation were examined in ovariectomized(OVX) or orchidectomized(ODX) rats with their intacts after feeding diet with or without 0.5% cholesterol. Body weight was significantly increased(p < 0.01) in OVX rats and significantly decreased(p < 0.01) in ODX rats compared to their respective intact rats, and cholesterol diet significantly(p < 0.05) decreased body weight in gonadectomized rats. Liver lobes from rats fed cholesterol diet were opaque and larger than those from rats find control dict, resulting in a significant increase(p < 0.01) in LW/BW ratio. Plasma and liver levels of total cholesterol were significantly increased (p < 0.01) in female rats regardless ovariectomy when find 0.5% cholesterol diet, but those levels in male rats were increased only when they were orchidectomized(p < 0.0l). Plasma HDL-cholesterol was significantly decreased(p < 0.05) in both sexes when find cholesterol diet. HDL-cholesterol were higher in female than male rats regardless treatments(p < 0.05). Liver triglyceride was significantly increased(p < 0.05) in both sexes when find cholesterol dict. Plasma level of triglyceride was not different among groups except significant decrease(p < 0.05) in cholesterol find ODX rats. Maximum platelet aggregation in female rats was significantly lower(p < 0.05) than male, but ovariectomy and cholesterol diet caused an increase te the level of male rats. Microscopic examination showed cholesterol diet caused a lipid accumulation in liver. Results indicate that intact female rats have higher response to hypercholestcrolemic diet than intact male rats and orchidectomy causes male rats more responsive to hypercholesterolemic diet. However, ovariectomy causes an increase female food efficiency ratio to the level of male rats, significantly increasing body weight.

• 대한치과보철학회지
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• 제37권5호
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• pp.687-697
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• 1999

A finite element analysis has been utilized to analyze stress and strain fields and design a new configuration in orthopedics and implant dentistry. Load transfer and stress analysis at implant bone interface are important factors from treatment planning to long term success. Bone configuration and quality are different according te anatomy of expecting implantation site. The purpose of this study was to compare the stress distribution in maxilla and mandible accord-ing to implant length and bone engagement types. A three dimensional axi-symmetric implant model(Nobel Biocare, Gothenburg, Sweden) with surrounding cortical and cancellous bone were designed to analyze the effects of bone engagement and implant length on stress distribution. ANSYS 5.5 finite element program was utilized as an interpreting toot. Three cases of unicortical anchorage model with 7, 10, 13 mm length and four cases of bicortical anchorage model with 5, 7, 10 and 13 mm length were compared both maxillary and mandibular single implant situation. Within the limits of study, following conclusions were drawn. 1. There is a difference in stress distribution according to cortical and cancellous bone thickness and shape. 2. Maximum stress was shown at the top of cortical bone area regardless of bone engagement types. 3. Bicortical engagement showed less stress accumulation when compared to unicortical case overall. 4. Longer the implant future length, less the stress on cortical bone area, however there is no difference in mandibular bicortical engagement case.

• 정보처리학회논문지A
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• 제10A권5호
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• pp.453-462
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• 2003

리우터의 IP 주소검색은 라우터에 도착한 IP 패킷의 목적지 주소를 이용하여 적절한 출력링크를 검색하고 결정하는 것이다. IP 주소검색은 라우터 성능의 병목지점 중의 하나로써 고속 백본망에 필요한 초고속 라우터 개발에 필수적인 부분이다. 본 논문은 보통의 펜티엄 CPU에서 능동적인 트라이(Trie) 압축기법을 이용하여 작은 메모리만으로 기가비트급 IP 주소검색을 실시할 수 있는 동적 트라이 압축(Dynamic Trie Compression) 자료구조를 소개한다. DTC 자료구조는 트라이를 압축하여 포워딩 테이블을 만들 때 테이블의 크기와 검색속도의 상관관계를 고려하여 능동적으로 테이블의 크기를 선태할 수 있다. 또한 트라이를 압축할 때 트라이의 구조를 반영하여 자료구조의 크기를 최소화함으로써 포워딩 테이블에 대한 IP 주소검색이 고속의 SRAM 캐시 검색이 되도록 한다. 실험결과에서 DTC 자료구조는 다양한 라우팅 테이블에 대해 능동적으로 최적의 압축을 제공함으로써 보통의 펜티엄 CPU에서 최대 $12.5{\times}10^5$ LPS(Lookup per second)를 기록하였다.

• 한국동물학회지
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• 제23권3호
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• pp.115-123
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• 1980

DNA 회복합성과 염색체이상과의 연관성여부를 추구하기 위하여 CHO 세포를 재료로 MNNG의 농도와 처리후 시간경과에 따른 절제회복율을 조사하고 이들 염색체 이상율과 비교하여 다음과 같은 결과를 얻었따. 1. MNNG에 의한 절제회복율은 $0.5 \\times 10^-5M$에서 $0.5 \\times 10^-5M$까지 농도의 증가에 따른 절제회복율의 증가를 보인다. 또 $1 \\times 10^-5M$ 처리후 0시간째는 절제회복율의 최고치를 보이다가 그후 점자 감소하여 24시간에는 0시간의 66%정도 나타난다. 2. MNNG에 의한 염색체이상은 $1 \\times 10^-5M$ 처리후 6시간에 최대치를 보이며 이상형의 대부분은 염색분체 절단을 나타낸다. 그러나 시간이 경과함에 따라 염색체분체절단은 감소하고 염색분체교환은 증가하여 24시간에는 두종류의 이상율이 비슷하게 이른다. 3. MNNG 처리후 시간경과에 따른 절제회복율은 전체이상율과 대체로 일치한다. 그러나 염색분체교환 또는 염색분체절단과는 어떤 비례관계도 보이지 않는다. 따라서 이같은 결과들은 MNNG에 의한 DNA 상해 및 그 회복은 염색체의 회복 현상과는 연관성이 없음을 암시하는 것이다.

• 대한전자공학회논문지TE
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• 제37권2호
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• pp.69-74
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• 2000

T-모양의 마이크로스트립 급전 구조를 갖는 슬롯 안테나는 정합을 쉽게 이룰 수 있고 대역폭이 기존의 급전 구조의 슬롯 안테나에 비하여 넓었다. 양방향으로 복사체를 갖는 슬롯 안테나가 한 방향으로만 복사하기를 원할 경우, 반사판을 별도로 설치해야 한다. 그러나 본 논문에서 제시한 한 방향으로만 복사체를 갖는 슬롯 안테나는 반사판 설치가 필요 없게 된다. 그래서 반사판을 포함하는 2-층의 유전체 층에 십자형 급전구조를 갖는 마이크로스트립 슬롯 복사체인 새로운 방법을 제시하였다. FDTD 법으로 해석하여 전계분포를 시간 영역에서 계산하였고, 이를 Fourier 변환시켜 슬롯 안테나의 반사손실, 전압 정재파비, 복사패턴을 주파수 영역에서 계산하였다. 그리고 슬롯의 길이(I/sub s/)와 폭(W/sub s/), 수평부 급전선의 길이(I/sub d/), 상측 수직 급전선의 길이(l/sub u/), offset 에 따라 대역폭이 민감하게 변한다. 설계변수들을 최적화한 후에 측정한 결과, 최대 대역폭은 중심 주파수 2.5㎓에서 1,850㎒의 광대역 특성을 얻었다.

• Journal of Biosystems Engineering
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• 제36권1호
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• pp.23-32
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• 2011

In this work, the finite element method was used to investigate the shifts of resonance frequencies and quality factor of whispering-gallery-mode (WGM) for an opto-fluidic ring resonator (OFRR) biosensor. To describe the near-field radiation transfer, the time-domain Maxwell's equations were employed and solved by using the in-plane TE wave application mode of the COMSOL Multiphysics with RF module. The OFRR biosensor model under current study includes a glass capillary with a diameter of 100 mm and wall thickness of 3.0 mm. The resonance energy spectrum curves in the wavelength range from 1545 nm to 1560 nm were examined under different biosensing conditions. We mainly studied the sensitivity of resonance shifts affected by changes in the effective thickness of the sensor resonator ring with a 3.0 mm thick wall, as well as changes in the refractive index (RI) of the medium inside ring resonators with both 2.5 mm and 3.0 mm thick walls. In the bulk RI detection, a sensitivity of 23.1 nm/refractive index units (RIU) is achieved for a 2.5 mm thick ring. In small molecule detection, a sensitivity of 26.4 pm/nm is achieved with a maximum Q-factor of $6.3{\times}10^3$. These results compare favorably with those obtained by other researchers.

• 한국IT서비스학회지
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• 제16권4호
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• pp.15-31
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• 2017

This study analyzes 45 Korea IT service companies from 2012 to 2016 using DEA analysis. Large enterprises, medium enterprises and small and medium enterprises (SMEs). CCR model and BCC model were used for efficiency analysis. Among the various analytical objects, the decision objects which yield the maximum output with minimum input are compared with other analysis objects. The relative inefficiency was measured through this, and Technical Efficiency (TE), Pure Technology Efficiency (PTE), Scale Efficiency (SE), scale profit, reference frequency were analyzed. Also, we analyzed the Technology Gap Ratio (TGR), which is the distance between production function and Meta-Frontier for each firm, using Meta-Frontier analysis. Finally, the Tobit model is used to analyze the sources of efficiency and inefficiency. The inputs are assets, capital, and employees, and the output factor is sales. The analysis shows that large firms are achieving technological achievements more efficiently than small and medium enterprises. As a result, medium-sized enterprises and SMEs can improve efficiency overall through efficient operation of workforce and appropriate combination of inputs such as assets and capital. Also, as a result of the influence factor analysis, it was found that the ratio of the managed asset ratio and the management cost ratio were significant factors influencing the efficiency of the IT service companies. This study suggests the efficiency analysis using DEA for many Korea IT service companies. Inefficient parts of each company are classified according to size and technology. Also, we identify the most efficient companies and analyze the causes of those companies whose profits are lower than their size.

• Journal of Biosystems Engineering
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• 제16권1호
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• pp.83-89
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• 1991

One of the most serious problems in Korean sericulture farms is to improve the adiabatic conditions for the simple silkworm rearing houses which has been widely adapted since early 1980'. Thus, this study is aimed to solve the problems by selecting the thermal screen material and by finding the method of its instalation. For the study, 4 kinds of materials which are (1) TE005,(2) NW60, (3) NW300 and (4) AL110 are selected and 4 different types of methods which are surrounding boundary of rearing bed(type A), surrounding inside of wall and ceiling (type B), installing on inside of wal ony (type C) and installing on ceiling Inly (type D) are installed. Decision criteria of the best combination of screen material and installation methods is made by calculating the heating load coefficients and by testing the application at the simple silkworm rearing houses. The obtained results are summarized as follows ; 1. The effect of thermal screen on reducing the thermal energy is remarkable. It saves energy more 50% than unscreened simple silkworm rearing houses. 2. From a stand point of a good screed material on thermal energy reduction, the NW300, AL110 and PE005 are recommanded materials. However, NW60 and PE005 are regarded as desirable materials from the practical point view. 3. Also, the effect on thermal energy reduction is largely affected by the method of thermal screen installation. The surrounding boundary of the silkworm rearing bed(type A) is the most desirable method to reduce the energy, which saves 56.6% of it. 4. In the practical application, NW60 and type A is considered to be the best combination of material and installation method. By this combination, the level of maximum heating load can be reduced at the rate of 43% for spring season and 40% for autumn season. 5. Another heating method, comparted heating, can be recommended to save the energy.

• 약학회지
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• 제45권2호
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• pp.220-226
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• 2001

A bioequivalence study of Lovastati $n^{TM}$ tablets (Dong Sung Pharmaceutical Co., Korea) to Mevaco $r^{TM}$ tablets (Choong Wae Pharmaceutical Co., Korea) was conducted according to the guidelines (No. 98-56) of Korea Food and Drug Administration (KFDA). Each tablet contained 20 mg of lovastatin. Eighteen healthy Korean male subjects received each formulation at a lovastatin dose of 80 mg (i.e., four tablets) in a 2 $\times$ 2 crossover study. There was a washout period of a week between the dose of the two formulations. Plasma concentrations of lovastatin acid were monitored by a GC/MS method for over a period of 12hr after each administration. The area under the plasma concentration-time curve from time zero to 12hr (AUC) was calculated by a linear trapezoidal method. The maximum plasma drug concentration ( $C_{max}$) and the time to reach $C_{max}$ ( $T_{max}$) were compiled from the plasma drug concentration-time data. Analysis of variance (ANOVA) of these parameters revealed that there are no differences in AUC and $C_{max}$ between the formulations. The apparent differences between the formulations in these parameters were 4.87 and 8.03% for AUC and $C_{max}$, respectively. Minimum detectable differences (%) at $\alpha$=0.1 and 1-$\beta$=0.8 were 17.84 and 15.36% for AUC and $C_{max}$ respectively. The 90% confidence intervals were -15.30~5.56 and -17.02-0.95% for AUC and $C_{max}$, respective1y. Thus, the criteria of the KFDA guidelines for the bioequivalence was satisfied, indicating Mevaco $r^{TM}$ tablets and Dong Sung Lovastati $n^{TM}$ tablets are bioequivalent.ivalent.ent.alent.ent.

• 한국광학회지
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• 제15권5호
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• pp.423-428
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• 2004

320${\times}$240 배열의 중적외선 대역(3.7 $\mu\textrm{m}$∼4.8 $\mu\textrm{m}$) MCT(HgCdTe) 검출기를 이용하여 분해능과 신뢰도가 대폭 향상된 소형$.$고성능의 적외선 열상센서를 설계, 제작하였다. 개발된 열상센서는 1∼20배의 고배율 줌 광학계로 설계하고 미세주사 기법을 적용하여 640${\times}$480의 화소를 재현하여 항공기의 항법 보조로부터 표적획득에 이르기까지 다양한 활용이 가능하다. 적용된 적외선 줌 광학계는 릴레이 형태의 재결상계로 설계되었으며 미세주사 장치의 개발로 7.6 cycles/mrad 까지 분해가 가능하며 최저배율에서 40$^{\circ}$${\times}$30$^{\circ}$의 초광각(super wide field of view)의 시계를 갖는다. 또한 불균일 보정기법과 히스토그램 가변방식의 결합을 통한 첨단 열 영상처리 기법을 제안하여 열상센서에 적용함으로써 고성능의 실시간 디지털 영상처리를 가능케 하였다. 본 신호처리기의 개발을 통해 획득된 열영상의 최소분해가능 온도차는 고배율에서 0.05K(＠1cycles/mrad) 이하의 우수한 결과를 보였다.