• Journal of applied mathematics & informatics
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• 제16권1_2호
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• pp.53-68
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• 2004

Numerical solutions for the viscous Cahn-Hilliard equation are considered using the Crank-Nicolson type finite difference method which conserves the mass. The corresponding stability and error analysis of the scheme are shown. The decay speeds of the solution in $H^1-norm$ are shown. We also compare the evolution of the viscous Cahn-Hilliard equation with that of the Cahn-Hilliard equation numerically and computationally, which has been given as an open question in Novick-Cohen[13].

• Journal of applied mathematics & informatics
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• 제22권1_2호
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• pp.49-65
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• 2006

A robust numerical method for a singularly perturbed second-order ordinary differential equation having two parameters with a discontinuous source term is presented in this article. Theoretical bounds are derived for the derivatives of the solution and its smooth and singular components. An appropriate piecewise uniform mesh is constructed, and classical upwind finite difference schemes are used on this mesh to obtain the discrete system of equations. Parameter-uniform error bounds for the numerical approximations are established. Numerical results are provided to illustrate the convergence of the numerical approximations.

• Journal of applied mathematics & informatics
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• 제39권5_6호
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• pp.623-641
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• 2021

In this paper, numerical treatment of singularly perturbed parabolic delay differential equations is considered. The considered problem have small delay on the spatial variable of the reaction term. To treat the delay term, Taylor series approximation is applied. The resulting singularly perturbed parabolic PDEs is solved using Crank Nicolson method in temporal direction with non-standard finite difference method in spatial direction. A detail stability and convergence analysis of the scheme is given. We proved the uniform convergence of the scheme with order of convergence O(N^-1 + (∆t)²), where N is the number of mesh points in spatial discretization and ∆t is mesh length in temporal discretization. Two test examples are used to validate the theoretical results of the scheme.

• 대한한의학회지
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• 제30권1호
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• pp.83-94
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• 2009

Background and Objectives: The skin barrier protects skin against a harmful environment. Its function includes an antimicrobial barrier as well as a physical barrier. Stress is harmful to the skin barrier and there are many studies on this, but there are few about the effect of stress during pregnancy on the skin barrier of offspring. The aim of this study was to investigate the effect of stress during pregnancy on the skin barrier of offspring by examination with the naked eye, cortisol, weight, TEWL and histologic tests. Materials and Methods: Male hairless mice ten weeks old were coupled with females for three days. After twelve days the females were divided into two groups. We stressed one group and not the other group. The offspring from the non-stressed (N group) and stressed (S group) grew up until four weeks. The S group was exposed to chronic mild stress using the chronic stress model protocol modified method of Wilner and Towell for a week. We made examinations with the naked eye, assessment of cortisol, weight, TEWL, and histologic test to contrast the S group with the N group. Statistical analysis was performed by using Mann-Whitney and Friedman test. Statistical significance was achieved if the probability was less than 5% (p<0.05). Results: 1. By making an examination with the naked eye, S group showed papules, creases and dryness on their skin, but N showed no change compared with normal skin. 2. There was no statistically significant difference between S group and N group in cortisol (p>0.05). 3. There was no statistically significant difference between S group and N group in weight. N group had less weight than S group (p<0.05). 4. There was no statistically significant difference between S group and N group in TEWL (p>0.05). 5. There was no statistically significant difference between S group and N group in TEWL recovery (p>0.05). 6. In TEWL and TEWL recovery, there was statistically significant difference by time between S group and N group (p<0.005). Histologically, S group showed a thicker epidermis and epidermal crest than N group. Conclusions: We found that stress during pregnancy has negative effects on the skin barrier of offspring. Though there were no statistically significant differences between S group and N group in TEWL recovery, we found evidence that the recovery of skin barrier function is interrupted by stress during pregnancy by examination with both the naked eye and histology.

• 원예과학기술지
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• 제28권6호
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• pp.1066-1071
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• 2010

자기보고식 설문평가와 컴퓨터 기반 심박변이도(Heart rate variability, HRV) 분석평가를 통해 원예치료가 우울증 환자의 정서개선에 미치는 효과를 알아보았다. 자기보고식 설문 평가는 정신적 스트레스, 신체적 스트레스, 불안, 우울 등 4가지 평가도구를 사용하였다. HRV 분석평가는 standard deviation of the N-N intervals(SDNN), square root of mean squared difference of successive N-N intervals(RMSSD), total power(TP), low-frequency/high-frequency ratio(LF/HF ratio)의 4개 분석지표를 이용하였다. 동일한 병원 소속 우울증 환자 30명을 대상으로 실험을 수행하였다. 이 가운데 실험군 15명을 대상으로 주 1회씩 12회 원예치료 프로그램을 실시하였고, 대조군에는 실시하지 않았다. 그 결과, 원예치료를 실시 한 실험군의 경우 자기보고식 설문평가는 물론 HRV 분석평가에서도 원예치료 후 우울 정서 개선 효과가 확인되었다. 특히 자기보고식 평가에서는 정신적 스트레스, 불안, 우울 척도에서 통계적으로도 유의한 효과가 나타났으며($p$<0.001), HRV 분석평가의 경우 TP 지표에서 통계적 유의성이 확인되었다($p$<0.05). SDNN, RMSSD, LF/HF ratio 지표 역시 눈에 띄게 호전되었으나 통계적 유의성은 없었다. 비록 HRV의 모든 분석지표들이 통계적 유의성을 나타내지는 않았지만, 이 연구를 통해 HRV 측정으로 원예치료 효과를 객관화된 수치로 제시할 수 있는 가능성을 확인하였다. 또한 주관적 평가와 객관적 평가를 도입한 본 실험 결과 원예치료가 우울증 환자의 심리적, 신체적 재활에 효과적임이 입증되었다.

• 정보보호학회논문지
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• 제10권3호
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• pp.37-48
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• 2000

서울Visual cryptography scheme is a simple method in which can be directly decoded the secret information in human visual system without performing any cryptographic computations. This scheme is a kind of secret sharing scheme in which if a secret of image type is scattered to n random images(slides) and any threshold (or more) of them are stacked together the original image will become visible. In this paper we consider (2, n) visual cryptography scheme and propose a new construction method in which the number of expanded pixels can be reduced by using the sample matrix. The proposed scheme can futhermore distribute the multiple secret image to each group according to the difference of relative contrast.

• 대한화학회지
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• 제16권6호
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• pp.369-372
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• 1972

메탄올, N, N-dimethylformamide 및 acetonitrile속에서 이염기성 카르복시산 $(HOOC(CH_2)_nCOOH$, n=0∼4)의 해리상수를 유리전극을 사용하여 전위차법으로 측정했다. 두 용매간에서 각 산의 전해리상수의 차는 거의 일정한 값이 되며, 이 값은 일염기성 카르복시산의 해리상수의 차와 거의 일치했다. 그리고 $K_1/K_2$의 값은 양성자성용매인 물과 메탄올에서보다 반양성자성용매인 N,N-dimethylformamide와 acetonitrile에서 훨씬 더 크다.

• 대한한방체열의학회지
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• 제3권1호
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• pp.60-66
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• 2004

Purpose This study is to examine of Neurometer for the diagnosis of cold hypersensitivity Method Among patients who visited the oriental gynecological department in Kangnam Korean Hospital from October. 2000 to December. 2000, 37 women were diagnosed as cold hypersensitivity by D.I.T.I. We measured the limbs' temperature by D.I.T.I. and Current perception threshold(CPT) of median N., ulnar N., radial N., peroneal N., sural N., tibial N., saphenous N. by neurometer Patients were divided into mild and severe group depending on the temperature difference between proximalis and distalis in limbs Result and Conclusion 1. In severe group, CPT of median N., ulnar N., radial N. was higher on 250Hz and 200Hz. 2. In severe group, Mean CPT of peroneal N., sural N., tibial N., saphenous N. was higher on every Hz.

• Child Health Nursing Research
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• 제14권1호
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• pp.14-21
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• 2008

Purpose: The aims of this study were to evaluate effects of massage therapy and the attachment promotion program with autistic children. Method: A quasi-experimental design was conducted with a convenience sample of 44 autistic children. The experimental group (n= 23) attended the massage therapy and the attachment promotion program for 4 months. The control group (n=21) only had the attachment promotion program. Measurements were made twice for both groups using the social maturity scale and child autism rating scale. Recording of mother-child attachment was done for 15 minutes in only the experimental group twice using video equipment. Results: After 4 months of interventions, there was significant difference on social maturity (F=9.01, p=.005) between the groups. However, there was no significant difference on CARS ((F=2.47, p=.124). The total scores of mother-child attachment between pre- and post-interventions showed a significant difference (Z=-3.42, p=.001). Conclusion: The results showed that massage therapy and the attachment promotion program might be an effective way for providing a chance to increase social maturation and to increase attachment between mother and autistic child.

• Journal of applied mathematics & informatics
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• 제26권3_4호
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• pp.689-706
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• 2008

In this paper, a fifth order numerical method is presented for solving singularly perturbed two point boundary value problems with a boundary layer at one end point. The two point boundary value problem is transformed into general first order ordinary differential equation system. A discrete approximation of a fifth order compact difference scheme is presented for the first order system. An asymptotically equivalent first order equation of the original singularly perturbed two point boundary value problem is obtained from the theory of singular perturbations. It is used in the fifth order compact difference scheme to get a two term recurrence relation and is solved. Several linear and non-linear singular perturbation problems have been solved and the numerical results are presented to support the theory. It is observed that the present method approximates the exact solution very well.