• Title/Summary/Keyword: $t_f$

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POSITIVE SOLUTIONS FOR NONLINEAR m-POINT BVP WITH SIGN CHANGING NONLINEARITY ON TIME SCALES

  • HAN, WEI;REN, DENGYUN
    • Journal of applied mathematics & informatics
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    • v.35 no.5_6
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    • pp.551-563
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    • 2017
  • In this paper, by using fixed point theorems in cones, the existence of positive solutions is considered for nonlinear m-point boundary value problem for the following second-order dynamic equations on time scales $$u^{{\Delta}{\nabla}}(t)+a(t)f(t,u(t))=0,\;t{\in}(0,T),\;{\beta}u(0)-{\gamma}u^{\Delta}(0)=0,\;u(T)={\sum_{i=1}^{m-2}}\;a_iu({\xi}_i),\;m{\geq}3$$, where $a(t){\in}C_{ld}((0,T),\;[0,+{\infty}))$, $f{\in}C([0,T]{\times}[0,+{\infty}),\;(-{\infty},+{\infty}))$, the nonlinear term f is allowed to change sign. We obtain several existence theorems of positive solutions for the above boundary value problems. In particular, our criteria generalize and improve some known results [15] and the obtained conditions are different from related literature [14]. As an application, an example to demonstrate our results is given.

THE STUDY OF THE SYSTEM OF NONLINEAR WAVE EQUATIONS

  • Jung, Tacksun;Choi, Q-Heung
    • Journal of the Chungcheong Mathematical Society
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    • v.20 no.3
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    • pp.261-267
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    • 2007
  • We show the existence of the positive solution for the system of the following nonlinear wave equations with Dirichlet boundary conditions $$u_{tt}-u_{xx}+av^+=s{\phi}_{00}+f$$, $$v_{tt}-v_{xx}+bu^+=t{\phi}_{00}+g$$, $$u({\pm}\frac{\pi}{2},t)=v({\pm}\frac{\pi}{2},t)=0$$, where $u_+=max\{u,0\}$, s, $t{\in}R$, ${\phi}_{00}$ is the eigenfunction corresponding to the positive eigenvalue ${\lambda}_{00}=1$ of the eigenvalue problem $u_{tt}-u_{xx}={\lambda}_{mn}u$ with $u({\pm}\frac{\pi}{2},t)=0$, $u(x,t+{\pi})=u(x,t)=u(-x,t)=u(x,-t)$ and f, g are ${\pi}$-periodic, even in x and t and bounded functions in $[-\frac{\pi}{2},\frac{\pi}{2}]{\times}[-\frac{\pi}{2},\frac{\pi}{2}]$ with $\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}}f{\phi}_{00}=\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}}g{\phi}_{00}=0$.

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New Record of Thapariella anastomusa (Trematoda: Thapariellidae) Metacercariae in Northern Thailand

  • Phalee, Waraporn;Phalee, Anawat;Wongsawad, Chalobol
    • Parasites, Hosts and Diseases
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    • v.56 no.1
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    • pp.49-52
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    • 2018
  • The family Thapariellidae has been reported in only 3 countries since 1990. The objective of this study was to identify Thapariella anastomusa metacercariae in snails in Thailand based on morphological traits using a light (LM) and a scanning electron microscope (SEM). A total of 94 Filopaludina snails were collected and identified as 50 F. martensi martensi and 44 F. doliaris. Metacercariae of T. anastomusa were recovered from the snails by the crushing method. The overall prevalence was 22.3% (21/94), and the mean intensity was 17.0 per snail. The prevalence in F. martensi martensi was 24.0% (12/50) and F. doliaris 20.5% (9/44) with the mean intensity of 18.8 and 14.8 per snail, respectively. SEM revealed traits such as a concave ventral body and well-developed oral and ventral suckers. This study represents the first report of T. anastomusa in South East Asia. While LM and SEM observations provide novel insights into T. anastomusa metacercarial morphology and life history, the trematode's life cycle remains unclear. To date, there has been no report of T. anastomusa causing infections in humans. However, the snails F. martensi martensi and F. doliaris carrying the infective stages of T. anastomosa are frequently consumed by Thai people. This consumption, particularly uncooked snails, may present a risk of Thapariella infections in humans.

An Acoustic Study of Relative Articulatory Positions of English Vowels and Korean Vowels

  • Ahn, Soo-Woong
    • Speech Sciences
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    • v.8 no.4
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    • pp.171-184
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    • 2001
  • American English vowels and Korean vowels were compared by the plotformant method. For American English vowels, six General American English speakers pronounced English words in the b_t environment. For Korean vowels eight Kyongsang dialect speakers and eight Seoul dialect speakers pronounced Korean words in the environments of k_t, p_t and t_t. The formant plots were obtained by plotting F1/F2 tokens of 13 American English vowels on the F1xF2 plane. In spite of personal variations the 13 vowel spaces of all six American English speakers maintained their relative positions with some overlaps. Clear distinctions were made between i-I, e-$\varepsilon$, u-$\sigma$, and o-c. The domain of c and $\alpha$ overlapped for three American English speakers, but it did not for three other speakers. The 8 Korean vowel spaces of Kyongsang dialect speakers and Seoul dialect speakers were very similar and maintained their relative positions. No distinction was made between e and $\varepsilon$. In contrast with American English e which is a neutral vowel, Korean e was a back vowel. The comparison of 13 American English vowel positions and 8 Korean Vowel positions is expected to shed some light on the errors of English vowel pronunciation of Korean learners.

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ASYMPTOTIC PROPERTY FOR NONLINEAR PERTURBED FUNCTIONAL DIFFERENTIAL SYSTEMS

  • Im, Dong Man;Goo, Yoon Hoe
    • Journal of the Chungcheong Mathematical Society
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    • v.29 no.1
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    • pp.1-11
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    • 2016
  • This paper shows that the solutions to nonlinear perturbed functional differential system $$y^{\prime}=f(t,y)+{\int}^t_{t_0}g(s,y(s),Ty(s))ds+h(t,y(t))$$ have the asymptotic property by imposing conditions on the perturbed part ${\int}^t_{t_0}g(s,y(s),Ty(s))ds,h(t,y(t))$ and on the fundamental matrix of the unperturbed system y' = f(t, y).

A Development of Macroscopic Simulation Model for Interrupted Flow using Shockwave (충격파를 이용한 거시적 단속류 시뮬레이션 모형개발)

  • Lee, Ho-Sang;Jung, Young-Je;Kim, Young-Chan;Kim, Dae-Ho
    • Journal of Korean Society of Transportation
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    • v.26 no.1
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    • pp.191-201
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    • 2008
  • It has been employed TRANSYT-7F and NETSIM to evaluate the validity and effectiveness of improvement on TSM(Transportation Systems Management). But T7F is hard to describe platoon compression and dispersion in actually, and NETSIM takes a long time for network coding, calibration and have difficulty in setting up saturation flow. While Shockwave Model have advantage which can describe platoon compression and dispersion in actually and shorten hours, convenience of application. But Shockwave Model apply unrealistic traffic flow relation ship(U-K curve) and simplify platoon because of difficulty in calculating shockwave's position and cross. For solving limitation of existing shockwave models, It develop new model with 2-regime linear model, New platoon model, Extended shockwave, etc. For verifying the validity of the proposed model, it was compared with delay of T7F and NETSIM by offset variation. In conclusion, it is thought that proposed model have outstanding performance to simulate traffic phenomenon.

Relationship between Body image and Depression of Diabetes Mellitus Patients (당뇨병환자의 신체상과 우울과의 관계)

  • Lee, Myung-Hwa;Song, Myung-Sook
    • The Korean Journal of Rehabilitation Nursing
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    • v.5 no.1
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    • pp.49-59
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    • 2002
  • The purpose of study was to identify relationship between body image and depression of diabetes mellitus patients. The subjects of study were 120 diabetes mellitus patients who were B hospital in Pusan. Data were collected from 15th April to 20th August, 1998. The instrument used for this study were Osgood's body image scale and Zung's depression scale. The collected data were analyzed frequency, percentage, mean, standard deviation, t-test, ANOVA, Scheffe test, Pearson's correlation coefficients. The results were as follows: 1. The mean score of body image was $68.91{\pm}18.04$, and the mean score of depression was $56.18{\pm}11.58$. 2. The score of body image according to marital status(t=-2.434, p=.016), economic status (F=6.252, p=.001), reason of different regular hospital visiting(F=3.017, p=.014), treatment method of diabetes mellitus(F=3.048, p=.013) were significantly difference. ere significantly difference. 3. The score of depression according to sex(t=2.353, p=.020), occupational status(F=4.657, p=.002), marital status(t=-2.325, p=.022), economic status(F=5.536, p=.001), regular hospital visiting(t=2.081, p=.040), reason of different regular hospital visiting(F=3.352, p=.007), treatment method of diabetes mellitus(F=3.102, p=.012), paticipation of diabetes mellitus(t=3.726, p=.000), paticipation of diabetes mellitus visiting(F=4.819, p=.003) were significantly difference. 5. Body image and depression was a significant negative correlation(r=-.679. p=.000). Conclusion: From this study, a relationship between body image and depression inpatients with diabetes mellitus was idetified. Therefore, nursing intervention are needed to promote body image and depression in patients with diabetes mellitus.

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Studies on the Light Fastness of Dyeings (3) Effect of Dye Concentration on the Visual Judgement of Fading (染色物의 日光에 對한 堅牢性에 關한 硏究 (第3報) 染料初濃度가 視覺에 依한 褪色判定結果에 미치는 影響)

  • Ha Wan Shik
    • Journal of the Korean Chemical Society
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    • v.11 no.1
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    • pp.12-16
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    • 1967
  • Fading of Chlorantine Fast Red 5B (C.I. Direct Red 81) on cotton fabric exposed to carbon are light was examined. It was observed that the dye had anomaly in CF curve slope, while normal in CFG one. Auther considered that the reason for discrepancy of the one with the other curve slope might be appeared from Weber-Fechner law, and derived following equation $F_v=[logC_0-log(C_0-C_0F_t/100)]{\times}100/(logC_0+b)$ where $F_t$; the proportion of dye faded after t hour exposure. $F_v$; the proportion of dye faded after t hour exposure, when a pattern is judged by visual method $C_0$; initial dye concentration. b; constant. also, the reason for increasing lightfastness with dye concentration was discussed on view of the above equation.

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Characterization of Fracture Transmissivity for Groundwater Flow Assessment using DFN Modeling (분리단열망개념의 지하수유동해석을 위한 단열투수량계수의 정량화 연구)

  • 배대석;송무영;김천수;김경수;김증렬
    • The Journal of Engineering Geology
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    • v.6 no.1
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    • pp.1-13
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    • 1996
  • The fracture transmissivity($T_f$) is the most important parameter of fracture in assessing groundwater flow in fractured rock masses by using the DFN(Discrete Fracture Network) modeling. $T_f$, the most sensitive parameter m DFN modeling, is dependent upon aperture, size and filling characteristics of each fracture set. In the field test, the accuracy of $T_f$ can be increased with Borehole Acoustic Scanning (Televiewer) and Fixed Interval Length(FIL) test in constant head. $T_f$ values measured from FIL test was modified and estimated by each fracture set on the basis of the Cubic Law and the information of aperture and filling characteristics obtained from Televiewer. The modified $T_f$ results in the increase of confidence and reliability of modeling results including the amount of tunnel inflow.And, this approach would reduce the uncertaintity of the assessment for groundwater flow in fractured rock masses using the DFN modeling.

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Rotatable Anisotropy Field in Exchange Coupled CoFe/MnIr(2.5 nm) Thin Films (교환 결합력을 갖는 CoFe/MnIr(2.5 nm) 박막의 회전 이방성 자기장 특성)

  • Yoon, Seok Soo;Kim, Dong Young
    • Journal of the Korean Magnetics Society
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    • v.27 no.3
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    • pp.77-81
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    • 2017
  • The rotatable anisotropy effect was observed in the ferromagnetic resonance measurement in exchange coupled ferromagnetic/antiferromagnetic thin films and it was due to rotation of antiferromagnetic layer by the exchange coupling energy. We analyzed the CoFe thickness dependence of rotatable anisotropy field and ferromagnetic resonance linewidth in exchange coupled $CoFe(t_F)/MnIr(2.5nm)$ thin films. The rotatable anisotropy field was inversely propositional to the CoFe thickness and it was well fitted by the rotatable anisotropy energy of $0.96erg/cm^2$. The ferromagnetic resonance linewidth were linearly propositional to the rotatable anisotropy field in $t_F$ < 50 nm, while it was more dominated by the eddy current effect in $t_F$ > 50 nm.