• Journal of applied mathematics & informatics
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• v.27 no.3_4
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• pp.475-487
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• 2009

This paper studies the iteration method of solving a type of second-order three-point boundary value problem with non-linear term f, which depends on the first order derivative. By using the upper and lower method, we obtain the sufficient conditions of the existence and uniqueness of solutions. Furthermore, the monotone iterative sequences generated by the method contribute to the minimum solution and the maximum solution. And the error estimate formula is also given under the condition of unique solution. We apply the solving process to a special boundary value problem, and the result is interesting.

• Journal of applied mathematics & informatics
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• v.28 no.3_4
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• pp.763-772
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• 2010

This paper deals with the existence of triple positive solutions for the nonlinear second-order three-point boundary value problem z"(t)+a(t)f(t, z(t), z'(t))=0, t $\in$ (0, 1), $z(0)={\nu}z(1)\;{\geq}\;0$, $z'(\eta)=0$, where 0 < $\nu$ < 1, 0 < $\eta$ < 1 are constants. f : [0, 1] $\times$ [0, $+{\infty}$) $\times$ R $\rightarrow$ [0, $+{\infty}$) and a : (0, 1) $\rightarrow$ [0, $+{\infty}$) are continuous. First, Green's function for the associated linear boundary value problem is constructed, and then, by means of a fixed point theorem due to Avery and Peterson, sufficient conditions are obtained that guarantee the existence of triple positive solutions to the boundary value problem. The interesting point is that the nonlinear term f is involved with the first-order derivative explicitly.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1420-1428
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• 2017

It is difficult to guarantee the reliability of the algorithm due to the difference of the sampling frequency among the various ECG databases used for the R wave detection in case of applying to different environments. In this study, we propose an optimal threshold setting method for R wave detection according to the sampling frequency of ECG signals. For this purpose, preprocessing process was performed using moving average and the squaring function based the derivative. The optimal value for the peak threshold was then detected according to the sampling frequency by changing the threshold value according to the variation of the signal and the previously detected peak value. The performance of R wave detection is evaluated by using 48 record of MIT-BIH arrhythmia database. When the optimal values of the differential section, window size, and threshold coefficient for the MIT-BIH sampling frequency of 360 Hz were 7, 8, and 6.6, respectively, the R wave detection rate was 99.758%.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1266-1266
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• 2001

Pasture composition, an important attribute determining sward condition and value, is normally assessed by hand separation, drying and measuring weight contribution of each species in the mixture. This is a tedious, time and labour consuming procedure. NIRS has demonstrated the potential for predicting botanical composition of swards, but most of the work has been carried out on dry samples. The aim of this work was to evaluate the feasibility of developing NIR models for predicting the white clover and ryegrass content in fresh or dry mixtures artificially prepared from pure samples of both species. Mixtures from pure stands of white clover(Trifolium repens) and perennial ryegrass (Lolium perenne) were prepared with different proportions (0 to 100%) of each species (fresh weight). A total of 55 samples were made (11 mixtures,5 cuts). Spectra (400 to 2500 nm) were taken from fresh chopped (rectangular cuvettes, transport sample module) samples, in a NIR Systems 6500 scanning monochromator controlled by the software NIRS 3 (Infrasoft International), which was also utilized for calibration development. Different math treatments (derivative order, subtraction gap and smooth segment) and a scatter correction treatment of the spectra (SNV and Detrend) were tested. Equations were developed by modified partial least squares. Prediction accuracy evaluated by cross-validation, showed that percentage of clover or ryegrass, as contribution in dry weight, can be successfully percentage of clover or ryegrass, as contribution in dry weight, can be successfully predicted either on fresh or dried samples, with equations developed by different math treatments. Best equations for fresh samples were developed including a first, second, or third derivative, whereas for dry samples best equations included a second or third derivative. Standard errors of ross validation were about 6% for fresh and 3.6% for dry samples, Coefficient of determination of cross validation (1-VR) were over 0.95 times the value of SECV for fresh samples and over 8 times the value of SECV for dry samples. Scatter correction (SNV and Detrend) in general improved prediction accuracy. It is concluded more precise on dried and ground samples, it can be used with an acceptable error level and less time and labour, on fresh samples.

• Journal of applied mathematics & informatics
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• v.31 no.1_2
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• pp.221-228
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• 2013

The method of upper and lower solutions and the generalized quasilinearization technique is developed for the existence and approximation of solutions to boundary value problems for higher order fractional differential equations of the type $^c\mathcal{D}^qu(t)+f(t,u(t))=0$, $t{\in}(0,1),q{\in}(n-1,n],n{\geq}2$ $u^{\prime}(0)=0,u^{\prime\prime}(0)=0,{\ldots},u^{n-1}(0)=0,u(1)={\xi}u({\eta})$, where ${\xi},{\eta}{\in}(0,1)$, the nonlinear function f is assumed to be continuous and $^c\mathcal{D}^q$ is the fractional derivative in the sense of Caputo. Existence of solution is established via the upper and lower solutions method and approximation of solutions uses the generalized quasilinearization technique.

• Bulletin of the Korean Mathematical Society
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• v.51 no.2
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• pp.329-338
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• 2014

In this paper, we study the method of upper and lower solutions and develop the generalized quasilinearization technique for the existence and approximation of solutions to some three-point nonlocal boundary value problems associated with higher order fractional differential equations of the type $$^c{\mathcal{D}}^q_{0+}u(t)+f(t,u(t))=0,\;t{\in}(0,1)$$ $$u^{\prime}(0)={\gamma}u^{\prime}({\eta}),\;u^{\prime\prime}(0)=0,\;u^{\prime\prime\prime}(0)=0,{\ldots},u^{(n-1)}(0)=0,\;u(1)={\delta}u({\eta})$$, where, n-1 < q < n, $n({\geq}3){\in}\mathbb{N}$, 0 < ${\eta},{\gamma},{\delta}$ < 1 and $^c\mathcal{D}^q_{0+}$ is the Caputo fractional derivative of order q. The nonlinear function f is assumed to be continuous.

• Journal of applied mathematics & informatics
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• v.28 no.5_6
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• pp.1323-1329
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• 2010

In this paper, a new fixed point theorem in cone is applied to obtain the existence of at least one positive pseudo-symmetric solution for the second order three-point boundary value problem {x" + f(t, x, x')=0, t $\in$ (0, 1), x(0)=0, x(1)=x($\eta$), where f is nonnegative continuous function; ${\eta}\;{\in}$ (0, 1) and f(t, u, v) = f(1+$\eta$-t, u, -v).

• Journal of Pharmaceutical Investigation
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• v.40 no.3
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• pp.175-180
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• 2010

Albumin-modification has been viewed as one of the most effective ways of extending the short in vivo lifetimes of peptide drugs by delaying glomerular filtration. In this study, we describe a new type 2 anti-diabetic exendin-4 (Ex4) peptide derivative with significant binding ability to human serum albumin (HSA). This exendin-4 derivative consists of a 4-branched polyethylene glycol $(PEG)_{5k}$ (Mw: 20 kDa) modified with three stearylamines ($C_{18}-NH_2$) and one exendin-4 on its branches. PEG and stearylamine were selected to provide functionality to increase molecular size and bind to albumin, respectively. This derivative ($3C_{18}-4PEG_{5k}$-Ex4) was shown to have larger molecular size (Ca. 152 kDa) than actual (25.0 kDa) when subjected to size-exclusion chromatography, and the fluorescein-tagged $3C_{18}-4PEG_{5k}$-Ex4 displayed significant binding to the HSA-immobilized Sepharose CL-4B resin using confocal laser scanning microscopy. Furthermore, $3C_{18}-4PEG_{5k}$-Ex4 was found to have acceptable anti-hyperglycemic efficacy via three consecutive oral glucose tolerance testings (OGTT) in fasted type 2 diabetic db/db mice. The $HD_{total}$ value ($57.6{\pm}12.3%$) of $3C_{18}-4PEG_{5k}$-Ex4 at a 50 nmol/kg dose was 2-fold greater than that ($31.0{\pm}8.7%$) of native exendin-4 in non-fasted db/db mice. Especially, the blood glucose levels in the mice group treated with $3C_{18}-4PEG_{5k}$-Ex4 did not rebound to ~150 mg/dL until 24 h after the injection, which obviously shows the extended hypoglycemia. We believe that this derivative has great pharmaceutical potential as a novel long-acting type 2 anti-diabetic injection treatment.

• The Korean Journal of Pesticide Science
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• v.2 no.1
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• pp.24-31
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• 1998

Chemical derivative synthesis of ricinine, an active compound of Ricinus communis which showed high mortality against brown planthopper (Nilaparvata lugens), was performed to improve its pesticidal activity and the toxicity of 12 synthetic derivatives against major insect pests and phytopathogenic fungi were examined. Carbamate derivatives of ricinine could be synthesized from the precursor of ricinine, chloronorricinine and norricinine, whereas the derivatives were not synthesized from chlororicinic acid and ricinic acid having ketone group of pyridine ring. In organophosphates, reaction with oxon type of phosphate gave better yield than thiono type. Among the organophosphate derivatives of ricinine, thiono type of derivative structure gave $96.3%{\sim}100%$ mortality of the brown planthopper and the two-spotted spider mite (Tetranychus urticae) at 500 ${\mu}g/ml$ level. On the other hand, carbamate derivatives did not show insecticidal activity. In the fungicidal activity of ricinine derivatives, the derivative having amino radical at the 2 position of ricinine gave 85 to 100% of mycelium growth inhibition effect against ten major plant pathogens at the 200 ${\mu}g/ml$ level. In particular, the control value of the derivative on the rice blast (Pyricularia grisea) and barley powdery mildew (Erysiphe graminis) at the 250 ${\mu}g/ml$ level in vivo under greenhouse conditions was 92% and 96%, respectively.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.140-144
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• 1990

On force control of robot, the transient response of the force is as important as the steady state value. We analyze the force for an 1 d.o.f. model. Based on the analysis, we finds out a desirable condition of the control system parameters for stability of the force. We propose a force rate feedback control for implementation. Through experiments we shows that the force can be controlled stably for an arbitrary environment.