• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2010년도 학술대회 초록집
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• pp.27-27
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• 2010

There have been several studies about empirical relation between seismic source parameters(e.g., focal mechanisms, depths, magnitudes, etc.) and T-wave observation. In order to delineate the relation, numerical and theoretical approaches to figure out T-wave excitation mechanism are required. In an attempt to investigate source radiation and wave scattering effects in the oceanic crust on T-wave envelopes, we perform three-dimensional numerical modeling to synthesize T-wave envelopes. We first calculate seismic P- and SV-wave energy on the seafloor using the Direct Simulation Monte Carlo based on the Radiative Transfer Theory, which enables us to take into account both realistic seismic source parameters and wave scattering in heterogeneous media, and then estimate excited T-wave energy by normal mode computation. The numerical simulation has been carried out considering the following different conditions: source types (strike and normal faults), source depths (shallow and deep), and wave propagation through homogeneous and heterogeneous Earth media. From the results of numerical modeling, we confirmed that T-wave envelopes vary according to spatial seismic energy distributions on the seafloor for the various input parameters. Furthermore, the synthesized T-wave envelopes show directional patterns due to anisotropic source radiation, and the slope change of T-wave envelopes caused by focal depth. Seismic wave scattering in the oceanic crust is likely to control the shape of envelopes.

• 대한수학회보
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• 제59권3호
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• pp.745-756
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• 2022

We study a nonlinear wave equation on finite connected weighted graphs. Using Rothe's and energy methods, we prove the existence and uniqueness of solution under certain assumption. For linear wave equation on graphs, Lin and Xie [10] obtained the existence and uniqueness of solution. The main novelty of this paper is that the wave equation we considered has the nonlinear damping term |u_t|^p-1·u_t (p > 1).

• 한국정보전자통신기술학회논문지
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• 제4권1호
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• pp.17-22
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• 2011

본 연구에서는 부정맥 판독을 위해 심전도 신호로부터 P파의 강조 및 검출 방법을 제안하였다. 이 방법에서는 고전적인 필터나 이동평균필터를 사용하지 않고 하강 기울기의 변곡점을 검출하기에 효과적인 하강 기울기 추적파를 이용하여 고주파 잡음을 무시해 주는 필터 용도로 사용함과 동시에 진폭이 낮고 불명확한 P파와 T파를 강조해 줌으로써 이들의 검출을 용이하게 하였다. 이 강조 및 검출 방법을 MIT/BIH 데이터에 적용하여 구현하였으며 그 실용성을 확인하였다.

• 한국수산과학회지
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• 제22권1호
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• pp.41-47
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• 1989

Using computer simulated irregular waves, variations of ocean wave statistics according to sea state are analyzed, and the reasonable conditions that transform the energy spectrum to individual wave statistics are discussed. Ocean wave statistics varying with sea state are found to respond linearly to the spectral peakedness parameter $Q_p$ and spectrum moments $m_n$ (n = 0, 1, 2${\cdots}{\cdots}\;\infty$ ). It is clarified that the 2nd-order spectrum moment is a reasonable parameter which represents the wave statistics including wave periods, and that the spectrum analysis should be carried out under the conditions of minimum data length of 10 times of peak period $T_p$ with time lag of $7T_p$ to satisfy the stable condition of wave statistics.

• 한국해안·해양공학회논문집
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• 제35권6호
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• pp.146-154
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• 2023

본 연구에서는 서해안 해상기상타워 2기에서 관측된 수면변동자료를 이용하여 해양특성을 구분하는 주요 인자인 첨두주기 T_p와 평균주기 T₀₂와 T_{m-1, 0}를 산정하고 이상자료의 비율, 상관관계 분석 및 최적 확률밀도함수를 추정하였다. 산정된 대표주기 중 첨두주기의 경우, 이상 자료의 비율은 각각의 지점에서 5.73 %, 0.67 %로 나타났으며, T₀₂는 4.35%, 0.01%, T_{m-1, 0}는 2.82%, 0.03%로 나타났다. 한편, T₀₂와 T_p 사이의 관계를 분석한 결과 각 지점별로 0.53, 0.63의 관계로 산정됐으며, T_{m-1, 0}와 T_p의 관계는 각각 1.15, 1.32로 나타났다. T₀₂와 T_{m-1, 0}는 서로 1.18, 1.22의 관계를 보이고 있었다. 산정된 대표주기의 최적 확률밀도함수를 추정한 결과, T_p는 각각의 지점에서 'Lognormal', 'Normal' 분포를 따르고 있었으며, T₀₂는 'Gamma', 'Normal' 분포, T_{m-1, 0}는 각각 'Log-normal', 'Normal' 분포가 우세한 것으로 나타났다. 이러한 결과는 서해안을 대상으로 수행되는 파랑 분석에 기초자료로 사용될 수 있을 것으로 판단된다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.175-176
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• 1998

The automated ECG diagnostic systems that are used in hospitals have low performance of P wave detection when faced with some diseases such as conduction block. So, the aim of this study is the improvement of detection performance in conduction block which is low in P wave detection. Median QRS-T segments were subtracted from the raw data and residual in the QRS-T regions was zeroed. After band pass filtering, we applied approximated length transformation to detect P wave.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 추계학술대회 논문집
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• pp.154-158
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• 2000

Hydraultic experiments were performed in 2-D were flume to investigate the stability o the breakwaters, the destruction of armor blocks and overtopping under irregular wave attack on the structures armored by \`Core-Loc\`. Overtopping rate and stability were examined and compared when armored by Core-Loc and by T.T.P. Results shows both type of blocks are stable and overtopping rates are similar in the adopted experimental condition. Therefore Core-Loc can replace some portion of T.T.P. which is uniquely used in Korea. Further integrated experimental data with Core-loc are need for destruction mechanism or overtopping rate.

• 한국직업건강간호학회지
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• 제29권2호
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• pp.114-122
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• 2020

Purpose: This study aimed to identify the effect of integrated nursing using cognicise and neurofeedback on cognition and α waves among elderly individuals. Methods: This quasi-experimental single group pretest-posttest study included 29 Korean adults aged 65 years or older who participated at a senior welfare center in Y city from February to May 2019. Each integrated nursing session consisted of cognicise (10 minutes) and neurofeedback (20 minutes). Subjects participated twice a week for 10 weeks. Structured questionnaires to assess participants' general characteristics and the Korean version of the Mini-Mental Status Examination for Dementia Screening (K-MMSE-DS) were applied. Alpha waves were measured using BrainMaster. Results: Following the integrated nursing program, alpha waves improved in F3 (t=2.41, p=.023), C3 (t=3.00, p=.006), C4 (t=2.60, p=.015), P3 (t=2.43, p=.022), O1 (t=2.30, p=.029), T3 (t=3.05, p=.005), T4 (t=2.28, p=.030), T5 (t=2.91, p=.007), Fz (t=2.30, p=.029), Cz (t=2.73, p=.011), and Pz (t=2.23, p=.034). Most subjects experienced improvement in concentration after participating in the intervention. Conclusion: This study provides evidence for the use of a neuroscientific approach including brain wave measurement to improve cognitive health among community-living elderly people.

• 한국실내디자인학회논문집
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• 제25권2호
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• pp.59-69
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• 2016

This study aimed to understand the importance of applying finishing materials into interior space, and to add meaning to the creation of functional space, associated interior finishing materials with brain science. To achieve this purpose, brainwave(EEG) experiment was conducted. The brainwave appearing when sensing the surface of interior finishing materials with hands was measured. The locations of the electrode were FP1, FP2, F3, F4, C3, C4, P3, P4, O1, O2, F7, F8, T3, T4, T5, T6, CZ, FZ, and PZ and in addition to these, AFZ was added. Eight(8) kinds of finishing materials: metallic material, film paper, lumbar, stone, glass, silk wallpaper, fabric, and paint were used to measure '${\alpha}$-wave against ${\beta}$ wave.' As a result, it was found that the most activated finishing material in term of relaxation was film paper, followed by metallic, glass, paint, fabric, stone, lumbar, and silk wallpaper. To explain in light of this, (1) '${\alpha}$-wave against ${\beta}$ wave' was the most activated at ch1-FP1 and ch2-FP2, and at ch17-AFZ and ch19-FZ, which indicated that metopic-prefrontal lobe showed the highest activation in relaxation. Film paper, among the finishing materials, showed the highest increase in relaxation. (2) In general, '${\alpha}$-wave against ${\beta}$ wave' relaxation was inhibited at ch13-T3 and ch14-T4, and at ch15-T5 and ch16-T6 and the arousal in the temporal lobe was prominent. Silk wallpaper, among the finishing materials, showed the highest arounsal effect. As a result of measuring the superficial touch on the silk wallpaper, which was regarded as the most rough material among the eight finishing materials, the arousal effect of ${\alpha}$-wave against ${\beta}$-wave, among the brainwave characteristics, was found to be the highest. (3) to judge from the scope of this experiment regarding the tactile sensation over the finishing materials, it is considered that the brainwave reaction sometimes appeared contrastive depending on whether the surface was smooth or rough and there also appeared a difference in relaxation and arousal reaction of the brainwave depending on whether the surface was hot or cold, but the sensation on the surface texture was often evaluated differently depending on who you were. For this reason, this study has some limitations.

• 대한수학회지
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• 제35권2호
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• pp.465-490
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• 1998

In this paper, we consider the existence and asymptotic behavior of solutions of the following problem: $u_{tt}$ -(t, x) - (∥∇u(t, x)∥(equation omitted) ＋ ∥∇v(t, x) (equation omitted)$^{\gamma}$ $\Delta$u(t, x)＋$\delta$│ $u_{t}$ (t, x)│sup p-1/ $u_{t}$ (t, x) = $\mu$│u(t, x) $^{q-1}$u(t, x), x$\in$$\Omega$, t$\in$[0, T], $v_{tt}$ (t, x) - (∥∇uu(t, x) (equation omitted) ＋ ∥∇v(t, x) (equation omitted)sup ${\gamma}$/ $\Delta$v(t, x)＋$\delta$ │ $v_{t}$ (t, x)│sup p-1/ $u_{t}$ (t, x) = $\mu$ u(t, x) $^{q-1}$u(t, x), x$\in$$\Omega$, t$\in$[0, T], u(0, x) = $u_{0}$ (x), $u_{t}$ (0, x) = $u_1$(x), x$\in$$\Omega$, u(0, x) = $v_{0}$ (x), $v_{t}$ (0, x) = $v_1$(x), x$\in$$\Omega$, u│∂$\Omega$=v│∂$\Omega$=0 T > 0, q > 1, p $\geq$1, $\delta$ > 0, $\mu$ $\in$ R, ${\gamma}$ $\geq$ 1 and $\Delta$ is the Laplacian in $R^{N}$.X> N/.