• 대한수학회지
• /
• 제53권4호
• /
• pp.929-967
• /
• 2016

Let p(t, x) be the fundamental solution to the problem $${\partial}^{\alpha}_tu=-(-{\Delta})^{\beta}u,\;{\alpha}{\in}(0,2),\;{\beta}{\in}(0,{\infty})$$. If ${\alpha},{\beta}{\in}(0,1)$, then the kernel p(t, x) becomes the transition density of a Levy process delayed by an inverse subordinator. In this paper we provide the asymptotic behaviors and sharp upper bounds of p(t, x) and its space and time fractional derivatives $$D^n_x(-{\Delta}_x)^{\gamma}D^{\sigma}_tI^{\delta}_tp(t,x),\;{\forall}n{\in}{\mathbb{Z}}_+,\;{\gamma}{\in}[0,{\beta}],\;{\sigma},{\delta}{\in}[0,{\infty})$$, where $D^n_x$ x is a partial derivative of order n with respect to x, $(-{\Delta}_x)^{\gamma}$ is a fractional Laplace operator and $D^{\sigma}_t$ and $I^{\delta}_t$ are Riemann-Liouville fractional derivative and integral respectively.

• Geomechanics and Engineering
• /
• 제7권6호
• /
• pp.633-647
• /
• 2014

Biopolymers, polymers produced by living organisms, are used in various fields (e.g., medical, food, cosmetic, medicine) due to their beneficial properties. Recently, biopolymers have been used for control of soil erosion, stabilization of aggregate, and to enhance drilling. However, the inter-particle behavior of such polymers on soil behavior are poorly understood. In this study, an artificial biopolymer (${\beta}$-1,3/1,6-glucan) was used as an engineered soil additive for Korean residual soil (i.e., hwangtoh). The geotechnical behavior of the Korean residual soil, after treatment with ${\beta}$-1,3/1,6-glucan, were measured through a series of laboratory approaches and then analyzed. As the biopolymer content in soil increased, so did its compactibility, Atterberg limits, plasticity index, swelling index, and shear modulus. However, the treatment had no effect on the compressional stiffness of the residual soil, and the polymer induced bio-clogging of the soil's pore spaces while resulting in a decrease in hydraulic conductivity.

• 천문학회보
• /
• 제41권1호
• /
• pp.47.2-47.2
• /
• 2016

The protons and helium ions in the solar wind are observed to possess anisotropic temperature profiles. The anisotropy appears to be limited by various marginal instability conditions. One of the efficient methods to investigate the global dynamics and distribution of various temperature anisotropies in the large-scale solar wind models may be that based upon the macroscopic quasi-linear approach. The present paper investigates the proton and helium ion anisotropy instabilities on the basis of comparison between the quasi-linear theory versus particle-in-cell simulation. It is found that the overall dynamical development of the particle temperatures is quite accurately reproduced by the macroscopic quasi-linear scheme. The wave energy development in time, however, shows somewhat less restrictive comparisons, indicating that while the quasi-linear method is acceptable for the particle dynamics, the wave analysis probably requires higher-order physics, such as wave-wave coupling or nonlinear wave-particle interaction. We carried out comparative studies of proton firehose instability, aperiodic ordinary mode instability, and helium ion anisotropy instability. It was found that the agreement between QL theory and PIC simulation is rather good. It means that the quasilinear approximation enjoys only a limited range of validity, especially for the wave dynamics and for the relatively high-beta regime.

• Ocean Systems Engineering
• /
• 제2권2호
• /
• pp.115-135
• /
• 2012

The very low natural frequencies of tension leg platforms (TLP's) have raised the concern about the significance of the action of hydrodynamic wave forces on the response of such platforms. In this paper, a numerical study using modified Morison equation was carried out in the time domain to investigate the influence of nonlinearities due to hydrodynamic forces and the coupling effect between surge, sway, heave, roll, pitch and yaw degrees of freedom on the dynamic behavior of TLP's. The stiffness of the TLP was derived from a combination of hydrostatic restoring forces and restoring forces due to cables and the nonlinear equations of motion were solved utilizing Newmark's beta integration scheme. The effect of wave characteristics such as wave period and wave height on the response of TLP's was evaluated. Only uni-directional waves in the surge direction was considered in the analysis. It was found that coupling between various degrees of freedom has insignificant effect on the displacement responses. Moreover, for short wave periods (i.e., less than 10 sec.), the surge response consisted of small amplitude oscillations about a displaced position that is significantly dependent on the wave height; whereas for longer wave periods, the surge response showed high amplitude oscillations about its original position. Also, for short wave periods, a higher mode contribution to the pitch response accompanied by period doubling appeared to take place. For long wave periods, (12.5 and 15 sec.), this higher mode contribution vanished after very few cycles.

• Bulletin of the Korean Chemical Society
• /
• 제31권2호
• /
• pp.442-446
• /
• 2010

Adenosine 3',5'-cyclic monophosphate (cAMP) is a second messenger responsible for a multitude of cellular responses. In this study, we utilized $\beta$-cyclodextrin ($\beta$-CD) as an artificial receptor with a hydrophobic cavity to elucidate the inclusion kinetics of cAMP in a hydrophobic environment using the ultrasonic relaxation method. The results revealed that the interaction of cAMP with $\beta$-CD followed a single relaxation curve as a result of host-guest interactions. The inclusion of cAMP into the $\beta$-CD cavity was found to be a diffusion-controlled reaction. The dissociation of cAMP from the $\beta$-CD cavity was slower than that of adenosine 5'-monophosphate (AMP). The syn and anti glycosyl conformations of adenine nucleotides are considered to play an important role in formation of the inclusion complex. Taken together, our findings indicate that hydrophobic interactions are involved in the inclusion complex formation of cAMP with $\beta$-CD and provide insight into the interactions of cAMP with cAMP-binding proteins.

• 한국해양학회지
• /
• 제29권3호
• /
• pp.296-303
• /
• 1994

회전하는 원통형 이층 유체에 하층 유체와 동일한 밀도의 유체를 경사진 하층 바 닥의 둘레를 통하여 주입시 하층 내부는 일정한 수직 운동을 하게 되며 이러한 수직운 동은 결국 하층 유체에 Sverdrup type의 운동인 남향의 서안 경계류와 북향의 내부 운 동을 발생시킨다. 이때 $\beta$-효과와 동시에 하층 유체가 상층 경계면과 만나게 하므로써 소위 극전선 효과를 갖고 있는 상층 유체의 운동 특성을 관찰하였다. 서안에서 의 순 압성, 동안에서 의 경압성 운동이 뚜렷하게 나타나고 특히 동안 경계류의 남향과 서안 경계류의 남향은 서안에서 의 이안 현상을 야기시킨다. 상층에 $\beta$-효과를 증가시 서안 경계류의 폭이 감소하는 이안 현상후 내부에 "eddy" 모양의 흐름이 존재한다. 한편 경압성 Rossby wave는 동안 부근에서 뚜렷하게 관측되나 서쪽으로 진행하면서 소멸되 는 현상이 관측되었다. 하층 유체에 국지적 지형 효과서 준 경우 상층수의 서안 경계 류 및 동안 경계류가 민감하게 반응하여 동안에서는 정상파 형태의 운동이 나타나고 서안에서는 이안 현상 없이 경계류의 폭이 증가함을 보인다. 이는 하층의 순압성 운동 이 지형 효과를 느끼는 반면, 그 영향은 상층에 직접전달되지 못하고 있음을 보여주고 있는 것이라 사료된다. 상층의 $\beta$-효과 증가시 internal radius보다 훨씬 큰 규모의 파형이 내부에 존재하는 특성을 보여 주고 있다. 보여 주고 있다.

• 성인간호학회지
• /
• 제25권6호
• /
• pp.644-654
• /
• 2013

Purpose: The purpose of this study was to examine the effects of aroma foot reflexology massage on mood states specifically depression and brain waves of elderly women with osteoarthritis. Methods: The study was a nonequivalent control group non-synchronized design. The participants were 62 elderly women with osteoarthritis. The instruments were the Korean-Profile of Mood States-Brief for mood states and 8-channel EEG (Electroencephalogram) system for brain waves. Data were collected from March to May, 2012. Twenty-six participants were assigned to the treatment group and twenty-six to the comparison group. The data were analyzed using SPSS/WIN 17.0 version program, and included descriptive statistics, t-test, and ANCOVA. The intervention was conducted three times a week for two weeks. Results: There were significantly improvement in reported depression. s. Brain waves (EEG) increased significantly in F3, T3 of ${\alpha}$ wave and in F4, T3, and P4 of ${\beta}$ wave between the two groups. Conclusion: Aroma foot reflexology massage can be utilized as an effective intervention to decrease depression of mood states, increase of ${\alpha}$, and ${\beta}$ brain wave on woman elderly with osteoarthritis.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 학술대회 논문집 정보 및 제어부문
• /
• pp.155-156
• /
• 2008

본 연구는 두피에서 발생하는 EEG(electroencephalog ram)신호를 측정한 후 두뇌활동과 관련된 지표 중 집중도를 추출하여 집중도의 크기에 따라 하드웨어를 제어하는 집중도 무선전송 시스템을 구연하고자 하였다. 뇌파신호를 측정하여 집중도를 추출하기 위해 두피의 좌, 우 두 채널을 사용하였으며 Biopac의 MP-100과 EEG100C을 이용하여 뇌파신호 계측, 증폭 및 필터링을 하였다. 계측된 EEG 신호로부터 특정 주파수 대역 및 스펙트럼을 분석하기 위해서 LabVIEW 8.5를 이용하여 FFT(Fast Fourier Transformation) 처리를 하였다. 이를 통해 ${\alpha}$파, ${\beta}$파, ${\theta}$파, ${\delta}$파 주파수영역으로 분류한 후 집중도 추출 알고리즘을 적용하여 집중도 지표를 추출하였고 추출된 집중도 신호를 무선전송하여 BCI(Brain Computer Interface) 기술에 응용하고자 레고 자동차에 적응하여 보았다.

• 한국소음진동공학회논문집
• /
• 제21권4호
• /
• pp.307-314
• /
• 2011

This study was focused on the influence of soundscape provided to the interior landscape on the improvement of occupants' sound environment. When soundscape was provided to occupants together with the interior landscape rather than simply providing interior landscape, the occupants' satisfaction seemed to be improved. The most preferred sound source among the three sound sources was considered as the sound of the grasshopper. When both of the interior landscape and the landscape substances was provided, the adjectives with the average difference of more than 1 are "Vicissitudinous", "Elegant" and "Cheerful". When the interior landscape and the sound source were provided, such adjectives as "Vicissitudinous", "Complex" and "Cheerful" are extracted. When all the variables were provided, such adjectives as "Vicissitudinous", "Abundant" and "Cheerful" seem to show the difference of more than 1. Regarding "Vicissitudinous", it was possible to know that the average difference of more than 1.5 was the biggest. Regarding the relative values of the ${\alpha}$ wave and the ${\beta}$ wave for each part, it seemed that the highest ${\alpha}$ wave was generated on the left parietal lobe of P3, while the lowest ${\beta}$ wave was generated on the left and right frontal lobes of Fp1 and Fp2. According to this study, it was shown that the soundscape and the interior landscape seemed to influence the improvement of the occupants' sound environment.

• 한국게임학회 논문지
• /
• 제17권2호
• /
• pp.165-174
• /
• 2017

본 연구는 건강 기능성 게임인 흡연시뮬레이션 게임의 몰입을 결정하는 요인에 대해 파악하고 이들 요인들이 몰입에 어떠한 영향을 미치는지 분석하였다. 특히 게임 중에 발생하는 뇌 활동 패턴이 게임몰입과 어떠한 상관관계를 가지는지 뇌파측정과 몰입과의 관계를 규명하고자 하였다. 이를 위해 게임몰입의 정도를 종속변인으로 설정하고 몰입에 영향을 미칠 수 있는 감정이입, 건강관심도, 생리적 지표인 뇌파(${\alpha},{\beta}$)를 독립변인으로 설정하여 회귀분석을 실시하였다. 연구결과 흡연시뮬레이션 게임에서 몰입에 감정이입, 건강관심도, ${\beta}$파는 정적으로 영향을 미치고 있었으며, ${\alpha}$파의 경우 부적으로 영향을 미치고 있음이 확인되었다. 본 연구는 기능성 게임몰입에 영향을 미칠 수 있는 사용자 경험과 신경생리학적 변화에 대하여 자기 보고와 더불어 뇌파측정을 통해 실증적으로 분석하고 게임몰입의 결정요인을 규명하고 있다는 점에서 이론적 의미가 있다.