• 제목/요약/키워드: Omega Methods

검색결과 261건 처리시간 0.022초

SUPERCONVERGENCE OF FINITE ELEMENT METHODS FOR LINEAR QUASI-PARABOLIC INTEGRO-DIFFERENTIAL EQUATIONS

  • Li, Qian;Shen, Wanfang;Jian, Jinfeng
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제8권2호
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    • pp.23-38
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    • 2004
  • We consider finite element methods applied to a class of quasi parabolic integro-differential equations in $R^d$. Global strong superconvergence, which only requires that partitions are quasi-uniform, is investigated for the error between the approximate solution and the Sobolev-Volterra projection of the exact solution. Two order superconvergence results are demonstrated in $W^{1,p}(\Omega)\;and\;L_p(\Omega)$, for $2\;{\leq}p\;<\;{\infty}$.

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Electronic Structure of Flavins. Inclusion of Methyl Groups in Molecular Orbital Treatments of Flavins

  • Pill-Soon Song
    • 대한화학회지
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    • 제16권3호
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    • pp.119-134
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    • 1972
  • Various MO methods with differing degrees of sophistication are shown to yield qualitatively consistent results for methyl isoalloxazins. However, with crude methods such as the HMO and ${\omega}$-technique, the choice of Coulomb and resonance integralsis critical, in contrast with simpler molecular systems. The empirical value of ${\omega}$=0.5 appears to be more reasonable than 1.4. Methyl groups in these flaving are best treated by the group orbital approximation. The pseudo-heteroatom approximation overestimates methyl hyperconfiguration with the Pariser-Parrpole SCR MO method. siglet ${\pi}{\rightarrow}{\pi}^*$ transition energies are calculated by the P-P-P method and agree reasonably with the experimental values. 2- and 4-Thioisoalloxazine analogs are also treated. Reactivity indices of the flavin molecule are presented, includeing superdelocalizability. frontier orbital and radical densities. Various aspects of the applications of these indices of the methyl groups on dipolemoments, inozation potentialsm elctron affinities, and spectra are decribed in detail.

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소형 도체면 구조 개루우프 안테나의 임피던스 특성 (Impedance Characteristics of Small Type Conductor Surface Open-loop Antenna)

  • 정주수
    • 한국컴퓨터정보학회논문지
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    • 제9권4호
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    • pp.93-97
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    • 2004
  • 본 논문에서는 수분센서용으로 적합한 구조의 안테나로 소형 도체면 구조의 개루우프 안테나를 모델로 제시하고, 그 동작특성을 모멘트법을 이용하여 수치해석하였다. 수치해석 결과 동작주파수 $300{\sim}500[MHz]$ 대역에서 안테나의 파라미터 값들의 변화에 따라 입력임피던스는 $50[{\Omega}]$으로 정합시킬 수 있었으며, 또한 개루우프 반경, 높이, 폭은 안테나의 공진주파수를 변화시키는 파라미터로 작용하였으며, 부하로 사용되는 인덕턴스 값은 안테나의 입력임피던스를 조절할 수 있는 파라미터로 작용하고 있음을 알 수 있었다.

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Bonhoeffer - van der Pol 오실레이터 모델에서의 미소 파라미터 섭동에 의한 카오스 제어 (A study on Controlling chaos for Bonhoeffer-van der Pol oscillation model by small parameter perturbation)

  • 배영철
    • 한국전자통신학회논문지
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    • 제1권1호
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    • pp.49-55
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    • 2006
  • Applied by periodic Stimulating Currents in Bonhoeffer -Van der Pol(BVP) model, chaotic and periodic phenomena occured at specific conditions. The conditions of the chaotic motion in BVP comprised 0.7182< $A_1$ <0.792 and 1.09< $A_1$ <1.302 proved by the analysis of phase plane, bifurcation diagram, and lyapunov exponent. To control the chaotic motion, two methods were suggested by the first used the amplitude parameter A1, $A1={\varepsilon}((x-x_s)-(y-y_s))$ and the second used the temperature parameterc, $c=c(1+{\eta}cos{\Omega}t)$ which the values of ${\eta},{\Omega}$ varied respectlvly, and $x_s$, $y_s$ are the periodic signal. As a result of simulating these methods, the chaotic phenomena was controlled with the periodic motion of periodisity. The feasibilities of the chaotic and the periodic phenomena were analysed by phase plane Poincare map and lyapunov exponent.

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CONVERGENCE OF THE GENERALIZED IMPLICIT EULER METHOD

  • Yu, Dong-Won
    • 대한수학회보
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    • 제29권1호
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    • pp.31-40
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    • 1992
  • We introduce the generalized Runge-Kutta methods with the exponentially dominant order .omega. in [3], and the convergence theorems of the generalized explicit Euler method are derived in [4]. In this paper we will study the convergence of the generalized implicit Euler method.

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Evidence-based estimation of health care cost savings from the use of omega-3 supplementation among the elderly in Korea

  • Hwang, Ji-Yun;Kim, Wu Seon;Jeong, Sewon;Kwon, Oran
    • Nutrition Research and Practice
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    • 제9권4호
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    • pp.400-403
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    • 2015
  • BACKGROUND/OBJECTIVES: By the year 2050, thirty-eight percent of the Korean population will be over the age of 65. Health care costs for Koreans over age 65 reached 15.4 trillion Korean won in 2011, accounting for a third of the total health care costs for the population. Chronic degenerative diseases, including coronary heart disease (CHD), drive long-term health care costs at an alarming annual rate. In the elderly population, loss of independence is one of the main reasons for this increase in health care costs. Korean heath policies place a high priority on the prevention of CHD because it is a major cause of morbidity and mortality. SUBJECTS/METHODS: This evidence-based study aims to the estimate potential health care cost savings resulting from the daily intake of omega-3 fatty acid supplementation. Potential cost savings associated with a reduced risk of CHD and the medical costs potentially avoided through risk reduction, including hospitalizations and physician services, were estimated using a Congressional Budget Office cost accounting methodology. RESULTS: The estimate of the seven-year (2005-2011) net savings in medical costs resulting from a reduction in the incidence of CHD among the elderly population through the daily use of omega-3 fatty acids was approximately 210 billion Korean won. Approximately 92,997 hospitalizations due to CHD could be avoided over the seven years. CONCLUSIONS: Our findings suggest that omega-3 supplementation in older individuals may yield substantial cost-savings by reducing the risk of CHD. It should be noted that additional health and cost benefits need to be revisited and re-evaluated as more is known about possible data sources or as new data become available.

Distribution of Glutathione S-Transferase Omega Gene Polymorphism with Different Stages of HBV Infection Including Hepatocellular Carcinoma in the Egyptian Population

  • Shaban, Nadia Z;Salem, Halima H;Elsadany, Mohamed A;Ali, Bahy A;Hassona, Ehab M;Mogahed, Fayed AK
    • Asian Pacific Journal of Cancer Prevention
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    • 제17권4호
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    • pp.2145-2150
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    • 2016
  • Background: Infection with hepatitis B virus (HBV) is a major global public health problem, with a wide spectrum of clinical manifestations. Human cytosolic glutathione-S-transferases (GSTs) include several classes such as alpha (A), mu (M), pi (P), sigma (S), zeta (Z), omega (O) and theta (T). The present study aimed to investigate the role of GST omega genes (GSTO1 and GSTO2) in different groups of patients infected with HBV. Materials and Methods: HBV groups were classified according to clinical history, serological tests and histological analysis into normal carriers (N), acute (A), chronic (CH), cirrhosis (CI) and hepatocellular carcinoma (HCC) cases. The study focused on determination of the genotypes of GST omega genes (GSTO1 and GSTO2) and GST activity and liver function tests. Results: The results showed that GSTO1 (A/A) was decreased in N, A, CH, CI and HCC groups compared to the C-group, while, GSTO1 (C/A) and GSTO1(C/C) genotypes were increased significantly in N, A, CH, CI and HCC groups. GSTO2 (A/A) was decreased in all studied groups as compared to the C-group but GSTO2(A/G) and GSTO2(G/G) genotypes were increased significantly. In addition, GST activities, albumin and TP levels were decreased in all studied groups compared to the C-group, while the activities of transaminases were increased to differing degrees. Conclusions: The results indicate that GSTO genetic polymorphisms may be considered as biomarkers for determining and predicting the progression of HBV infection.

하수오(何首烏)의 안트라퀴논 함량분석 (Quantitative analysis of anthraquinones in Polygonum multiflorum Thunberg)

  • 이혜원;박소영;추병길;채성욱;이아영;김호경
    • 한국한의학연구원논문집
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    • 제13권3호
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    • pp.157-163
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    • 2007
  • Objective: Polygonum multiflorum Thunberg (Polygonaceae) has been traditionally used as a tonic and the purgative in China and Korea. The genus Polygonum is a source of a wide range of phenolic compound, flavanoids, anthraquinones, stilbenes and tannins. In this study, three anthraquinones were isolated and quantitative determination of anthraquinones from P multiflorum has been developed for quality standardization. Methods : Three anthraquinone derivatives were isolated from a methanol extract of the radix of P. multiflorum by the chromatographic separation. Their structures were identified as emodin, physcion and ${\omega}$-hydroxyemodin on the basis of spectral data (MS, lH-NMR, 13C-NMR) and chemical analysis. HPLC analysis was performed to determine the contents of emodin, physcion, chrysophanol, rhein and ${\omega}$-hydroxyemodin in P. multiflorum from different specimens were collected from twenty Korean markets. Results: According to the results, the contents of emodin, physcion, chrysophanol, rhein and ${\omega}$-hydroxyemodin were 0.145%, 0.434%, 0.016%, 0.026%, 0.030% by HPLC, respectively. Conclusions : In these results, we have determined the contents of emodin, physcion, chrysophanol, rhein and ${\omega}$-hydroxyemodin in P. multiflorum, respectively. We hope that this study will contribute to the standardization and quality control of herbal medicine.

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Effects of aeration and centrifugation conditions on omega-3 fatty acid production by the mixotrophic dinoflagellate Gymnodinium smaydae in a semi-continuous cultivation system on a pilot scale

  • Ji Hyun You;Hae Jin Jeong;Sang Ah Park;Se Hee Eom;Hee Chang Kang;Jin Hee Ok
    • ALGAE
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    • 제39권2호
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    • pp.109-127
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    • 2024
  • High production and efficient harvesting of microalgae containing high omega-3 levels are critical concerns for industrial use. Aeration can elevate production of some microalgae by providing CO2 and O2. However, it may lower the production of others by generating shear stress, causing severe cell damage. The mixotrophic dinoflagellate Gymnodinium smaydae is a new, promising microalga for omega-3 fatty acid production owing to its high docosahexaenoic acid content, and determining optimal conditions and methods for high omega-3 fatty acid production and efficient harvest using G. smaydae is crucial for its commercial utilization. Therefore, to determine whether continuous aeration is required, we measured densities of G. smaydae and the dinoflagellate prey Heterocapsa rotundata in a 100-L semi-continuous cultivation system under no aeration and continuous aeration conditions daily for 9 days. Furthermore, to determine the optimal conditions for harvesting through centrifugation, different rotational speeds of the continuous centrifuge and different flow rates of the pump injecting G. smaydae + H. rotundata cells into the centrifuge were tested. Under continuous aeration, G. smaydae production gradually decreased; however, without aeration, the production remained stable. Harvesting efficiency and the dry weights of omega-3 fatty acids of G. smaydae + H. rotundata cells at a rotational speed of 16,000 rpm were significantly higher than those at 2,000-8,000 rpm. However, these parameters did not significantly differ at injection pump flow rates of 1.0-4.0 L min-1. The results of the present study provide a basis for optimized production and harvest conditions for G. smaydae and other microalgae.

The effects of the DASH diet education program with omega-3 fatty acid supplementation on metabolic syndrome parameters in elderly women with abdominal obesity

  • Choi, Seung-Hye;Choi-Kwon, Smi
    • Nutrition Research and Practice
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    • 제9권2호
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    • pp.150-157
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    • 2015
  • BACKGROUND/OBJECTIVES: The purpose of this study was to investigate the overall effects of a tailored Dietary Approaches to Stop Hypertension (DASH) nutritional intervention program which included omega-3 fatty acids supplementation, on dietary self-efficacy, dietary knowledge, and dietary behaviors in Korean elderly women with abdominal obesity. Furthermore, we investigated the effects of the program on metabolic syndrome parameters including the antioxidant capacities in these subjects. SUBJECTS/METHODS: A randomized, controlled trial was conducted for 8 weeks. The experimental group (n = 21) received a weekly tailored nutritional program for 8 weeks and the control group (n = 18) received only one educational session. The clinical survey was conducted before and after the intervention period. RESULTS: After the intervention, dietary self-efficacy (P = 0.023), frequency of fruit intake (P = 0.019), and dietary fiber intake (P = 0.044) were higher in the experimental group than in the control group. The oxidative stress (P < 0.001) was lower in the experimental group than in the control group. Moreover, low density lipoprotein (LDL) cholesterol (P = 0.023) had significantly decreased in the experimental group but not in the control group after the intervention. CONCLUSIONS: The intervention program including omega-3 fatty acid supplementation had a positive effect on dietary self-efficacy, dietary behaviors, and oxidative stress among aged women with abdominal obesity.