• Title/Summary/Keyword: Omega Methods

Search Result 261, Processing Time 0.022 seconds

Failure Time Prediction by Nonlinear Least Square Method with Deformation Data (계측 자료의 비선형최소자승법을 이용한 파괴시간 예측)

  • Yoon, Yong-Kyun;Kim, Byoung-Chul;Jo, Young-Do
    • Tunnel and Underground Space
    • /
    • v.19 no.6
    • /
    • pp.558-566
    • /
    • 2009
  • Time-dependent behavior is a basic mechanical property of rocks. Predicting the failure time of rock structures by analyzing the time-dependent characteristic is important and problematic. It is tried to predict the failure time of tunnel, slope & laboratory creep test specimen from measured displacement(or strain) and rate with relationship suggested by Voight($\ddot{\Omega}=A\dot{\Omega}^\alpha$, where $\Omega$ is a measurable quantity such as strain & displacement and A & $\alpha$ are constants). A & $\alpha$ are estimated through applying the nonlinear least square method to the single and double integrated Voight's equations and utilized to predict the failure time. Predicted failure time is in accordance with real one except minor error. Linear inverse rate method applied to creep strain and rate yields a poor linear correlation of data and precision of predicted failure time is not better than methods using strain and rate.

Effect of the Sheath Layer Ground of Telecommunication Cable to Induced Voltage Measurement (통신 케이블 쉬스 층 접지가 전력선 전자유도 전압 측정에 미치는 영향)

  • Lee, Sangmu
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.16 no.1
    • /
    • pp.713-719
    • /
    • 2015
  • The change in induced voltage according to the relationship of ground connection between the aluminum sheath layer and a conductor pair in a general telecommunication cable is analyzed. When a measurement is practiced under the condition of separated sheath grounds with an averaged ground resistance of $42.6{\Omega}$, the induced voltage decreases 10 % to the induced voltage without sheath grounds. The induced voltage decreases approximately 50 % in the case of a one-sided common ground and decreases by more than 90 % in the case of a both-sided common ground. This experimental result is similar to the values calculated using the methods of the ITU Directives. In addition, according to a comparison analysis utilizing this ITU method, the measurement error range will be below 10 % in the state of ground resistance of central office less than $10{\Omega}$ and for the terminal side with $100{\Omega}$ less or more.

Evaluation of Major Nutrients of Domestic Farmed Eels Anguilla japonica (국내 양식 뱀장어 (Anguilla japonica)에서의 주요 영양학적 성분의 평가)

  • Cho, Hye-Sun;Choi, Jong-Hwan;Ko, Hong-Beom;Seo, Jae-Sung;Ahn, Jun-Cheul
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.44 no.3
    • /
    • pp.237-242
    • /
    • 2011
  • To evaluate the proximate composition and main nutritive ingredients (vitamin A, $V_A$; vitamin E, $V_E$; cholesterol; the composition of fatty acids) between eels cultured in different domestic eel farms, we analyzed edible parts of eels that were cultured in three "Water Recirculation System (WRS)" farms and three "Still-Water System (SWS)" farms. We found differences in crude protein, crude lipids and the ash content of eel meat between the farms, but water content showed no significant difference. $V_A$ and $V_E$ contents did not show meaningful differences between the two culture methods, but there was a noticeable distinction between the eel farms. In particular, $V_E$ content showed significant differences between the eels of each farm (highest farm, about 25 mg/100 g dry wt; lowest farm, about 1 mg/100 g dry wt). The fatty acids of cultured eels were composed of monoenes (MUFA, 55-60%), saturates (SFA, 30-33%), $\omega$-6 highly unsaturates (HUFA, 1.6-2%) and $\omega$-3 HUFA (8-9.2%). The MUFA content of WRS eels ($59.9{\pm}1.97%$) was higher than that of SWS eels ($55.8{\pm}0.48%$). The contents of other fatty acids were higher in SWS eels (SFA, $33.0{\pm}0.52%$; $\omega$-6FUFA, $1.98{\pm}0.2%$; $\omega$-3 HUFA, $9.2{\pm}0.67%$) than in WRS eels (SFA, $30.5{\pm}1.34%$; $\omega$-6 HUFA, $1.62{\pm}0.19%$; $\omega$-3 HUFA, $8.0{\pm}0.5%$).

Association between fish and shellfish, and omega-3 PUFAs intake and CVD risk factors in middle-aged female patients with type 2 diabetes

  • Kim, Hyesook;Park, Seokyung;Yang, Hyesu;Choi, Young Ju;Huh, Kap Bum;Chang, Namsoo
    • Nutrition Research and Practice
    • /
    • v.9 no.5
    • /
    • pp.496-502
    • /
    • 2015
  • BACKGROUND/OBJECTIVES: This study was performed to investigate the association between the dietary intake of fish and shellfish, and omega-3 polyunsaturated fatty acids (PUFAs) and cardiovascular disease (CVD) risk factors in the middle-aged Korean female patients with Type 2 diabetes (T2D). SUBJECTS/METHODS: A cross-sectional analysis was performed with 356 female patients (means age: 55.5 years), who were recruited from the Huh's Diabetes Clinic in Seoul, Korea between 2005 and 2011. The dietary intake was assessed by a validated semi-quantitative food frequency questionnaire and analyzed using the Computer Aided Nutritional Analysis program (CAN-Pro) version 4.0 software. RESULTS: In a multiple regression analysis after the adjustment for confounding factors such as age, BMI, duration of diagnosed T2D, alcohol consumption, fiber intake, sodium intake, and total energy intake, fish and shellfish intake of the subjects was negatively associated with triglyceride and pulse wave velocity (PWV). Omega-3 PUFAs intake was negatively associated with triglyceride, systolic blood pressures, diastolic blood pressures, and PWV. The multiple logistic regression analysis with the covariates showed a significant inverse relationship between the omega-3 PUFAs consumption and prevalence of hypertriglyceridemia [OR (95% CI) for greater than the median compared to less than the median: 0.395 (0.207-0.753)]. CONCLUSIONS: These results suggest that the consumption of fish and shellfish, good sources of omega-3 PUFAs, may reduce the risk factors for CVD in the middle-aged female patients with T2D.

Effect of omega-3 plus methylphenidate as an alternative therapy to reduce attention deficit-hyperactivity disorder in children

  • Mohammadzadeh, Soleiman;Baghi, Narmin;Yousefi, Fayegh;Yousefzamani, Bahar
    • Clinical and Experimental Pediatrics
    • /
    • v.62 no.9
    • /
    • pp.360-366
    • /
    • 2019
  • Background: Attention deficit-hyperactivity disorder (ADHD) is one of the most common chronic behavioral disorders in school-aged children. Purpose: This study aimed to evaluate the effect of omega-3 supplementation as an alternative therapy for ADHD, which can be caused by vitamin and mineral deficiencies. Methods: This was a double-blinded clinical trial study. Sixty-six children with ADHD (aged 6-12 years) referred to our child and adolescent psychiatric educational and therapeutic clinic were selected based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision criteria. Instruments including the Parent ADHD Rating Scale were used to assess ADHD at 0, 2, 4, and 8 weeks during the study. Results: The results showed no statistically significant difference between the methylphenidate with omega-3 group and methylphenidate with placebo group based on the Parents ADHD Rating Scale between week 0 ($P{\geq}0.96$) and week 8 ($P{\geq}0.75$). There were no significant intergroup differences between the Inattention ($P{\geq}0.48$) and hyperactivity/impulsivity ($P{\geq}0.80$) subscale scores on the Parents ADHD Rating Scale. The most common drug complications in the methylphenidate with placebo and methylphenidate with omega-3 groups were anorexia (27 [54%] vs. 41 [60.29%], respectively) and diarrhea (10 [20%] vs. 8 [11.76%], respectively), but the differences were not statistically significant (P>0.05). Conclusion: Our results demonstrate that a specific dose of omega-3 for 8 weeks had no effect on ADHD.

THE TRAPEZOIDAL RULE WITH A NONLINEAR COORDINATE TRANSFORMATION FOR WEAKLY SINGULAR INTEGRALS

  • Yun, Beong-In
    • Journal of the Korean Mathematical Society
    • /
    • v.41 no.6
    • /
    • pp.957-976
    • /
    • 2004
  • It is well known that the application of the nonlinear coordinate transformations is useful for efficient numerical evaluation of weakly singular integrals. In this paper, we consider the trapezoidal rule combined with a nonlinear transformation $\Omega$$_{m}$(b;$\chi$), containing a parameter b, proposed first by Yun [14]. It is shown that the trapezoidal rule with the transformation $\Omega$$_{m}$(b;$\chi$), like the case of the Gauss-Legendre quadrature rule, can improve the asymptotic truncation error by using a moderately large b. By several examples, we compare the numerical results of the present method with those of some existing methods. This shows the superiority of the transformation $\Omega$$_{m}$(b;$\chi$).TEX>).

MAX-NORM ERROR ESTIMATES FOR FINITE ELEMENT METHODS FOR NONLINEAR SOBOLEV EQUATIONS

  • CHOU, SO-HSIANG;LI, QIAN
    • Journal of the Korean Society for Industrial and Applied Mathematics
    • /
    • v.5 no.2
    • /
    • pp.25-37
    • /
    • 2001
  • We consider the finite element method applied to nonlinear Sobolev equation with smooth data and demonstrate for arbitrary order ($k{\geq}2$) finite element spaces the optimal rate of convergence in $L_{\infty}\;W^{1,{\infty}}({\Omega})$ and $L_{\infty}(L_{\infty}({\Omega}))$ (quasi-optimal for k = 1). In other words, the nonlinear Sobolev equation can be approximated equally well as its linear counterpart. Furthermore, we also obtain superconvergence results in $L_{\infty}(W^{1,{\infty}}({\Omega}))$ for the difference between the approximate solution and the generalized elliptic projection of the exact solution.

  • PDF

MULTIPLICITY RESULTS OF CRITICAL LOCAL EQUATION RELATED TO THE GENUS THEORY

  • Mohsen Alimohammady;Asieh Rezvani;Cemil Tunc
    • Communications of the Korean Mathematical Society
    • /
    • v.38 no.4
    • /
    • pp.1045-1061
    • /
    • 2023
  • Using variational methods, Krasnoselskii's genus theory and symmetric mountain pass theorem, we introduce the existence and multiplicity of solutions of a parameteric local equation. At first, we consider the following equation $$\{-div[a(x,{\mid}{\nabla}u{\mid}){\nabla}u]\,=\,{\mu}(b(x){\mid}u{\mid}^{s(x)-2}-{\mid}u{\mid}^{r(x)-2})u\;in\;{\Omega},\\u\,=0\,on\;{\partial}{\Omega},$$ where Ω⊆ ℝN is a bounded domain, µ is a positive real parameter, p, r and s are continuous real functions on ${\bar{\Omega}}$ and a(x, ξ) is of type |ξ|p(x)-2. Next, we study boundedness and simplicity of eigenfunction for the case a(x, |∇u|)∇u = g(x)|∇u|p(x)-2∇u, where g ∈ L(Ω) and g(x) ≥ 0 and the case $a(x,\,{\mid}{\nabla}u{\mid}){{\nabla}u}\,=\,(1\,+\,{\nabla}u{\mid}^2)^{\frac{p(x)-2}{2}}{\nabla}u$ such that p(x) ≡ p.

Synthesis of Dinitro ${\alpha},{\omega}$--Diols from ${\alpha},{\omega}$--Diols (${\alpha},{\omega}$-디올로부터 디니트로 ${\alpha},{\omega}$--디올의 합성)

  • Kyoo-Jyun Chung;Il-Gyo Park
    • Journal of the Korean Chemical Society
    • /
    • v.37 no.2
    • /
    • pp.244-248
    • /
    • 1993
  • Nitroalcohols were prepared by a substitution reaction from the corresponding bromoalcohols. The second nitro group was introduced via different methods depending on the carbon chain length. 3,3-Dinitro-1-propanol was obtained by an intramolecular varient of the alkaline nitration method. Whereas 5,5-dinitro-1-pentanol was given by the catalytic oxidative nitration. 3,3-Dinitro-1-propanol and 5,5-dinitro-1-pentanol were converted to 3,3-dinitro-1,6-hexanediol and 4,4-dinitro-1,8-octanediol via Michael reaction with acrolein followed by the reduction of the resulting aldehydes. Acetyl group was a good protecting group for the substitution reaction while THP was for the catalytic oxidative nitration.

  • PDF

EXISTENCE OF POSITIVE SOLUTIONS FOR A CLASS OF QUASILINEAR ELLIPTIC SYSTEM WITH CONCAVE-CONVEX NONLINEARITIES

  • Yin, Honghui;Yang, Zuodong
    • Journal of applied mathematics & informatics
    • /
    • v.29 no.3_4
    • /
    • pp.921-936
    • /
    • 2011
  • In this paper, our main purpose is to establish the existence of weak solutions of a weak solutions of a class of p-q-Laplacian system involving concave-convex nonlinearities: $$\{\array{-{\Delta}_pu-{\Delta}_qu={\lambda}V(x)|u|^{r-2}u+\frac{2{\alpha}}{\alpha+\beta}|u|^{\alpha-2}u|v|^{\beta},\;x{\in}{\Omega}\\-{\Delta}p^v-{\Delta}q^v={\theta}V(x)|v|^{r-2}v+\frac{2\beta}{\alpha+\beta}|u|^{\alpha}|v|^{\beta-2}v,\;x{\in}{\Omega}\\u=v=0,\;x{\in}{\partial}{\Omega}}$$ where ${\Omega}$ is a bounded domain in $R^N$, ${\lambda}$, ${\theta}$ > 0, and 1 < ${\alpha}$, ${\beta}$, ${\alpha}+{\beta}=p^*=\frac{N_p}{N_{-p}}$ is the critical Sobolev exponent, ${\Delta}_su=div(|{\nabla}u|^{s-2}{\nabla}u)$ is the s-Laplacian of u. when 1 < r < q < p < N, we prove that there exist infinitely many weak solutions. We also obtain some results for the case 1 < q < p < r < $p^*$. The existence results of solutions are obtained by variational methods.