• Journal of Biomedical Engineering Research
• /
• v.24 no.1
• /
• pp.1-8
• /
• 2003

The job of long distance driving is likely to be fatiguing and requires long period alertness and attention, which make considerable demands of the driver. Driving fatigue contributes to driver related with accidents and fatalities. In this study, we investigated the relationship between the number of hours of driving and driving fatigue using heart rate variability(HRV) signal. With a more traditional measure of overall variability (standard deviation, mean, spectral values of heart rate). Nonlinear characteristics of HRV signal were analyzed using Approximate Entropy (ApEn) and Poincare plot. Five subjects drive the four passenger vehicle twice. All experiment number was 40. The test route was about 300Km continuous long highway circuit and driving time was about 3 hours. During the driving, measures of electrocardiogram(ECG) were performed at intervals of 30min. HRV signal, derived from the ECG, was analyzed using time, frequency domain parameters and nonlinear characteristic. The significance of differences on the response to driving fatigue was determined by Student's t-test. Differences were considered significant when a p value < 0.05 was observed. In the results, mean heart rate(HRmean) decreased consistently with driving time, standard deviation of RR intervals(SDRR), standard deviation of the successive difference of the RR intervals(SDSD) increased until 90min. Hereafter, they were almost unchanging until the end of the test. Normalized low frequency component $(LF_{norm})$, ratio of low to high frequency component (LF/HF) increased. We used the Approximate Entropy(ApEn), Poincare plot method to describe the nonlinear characteristics of HRV signal. Nonlinear characteristics of HRV signals decreased with driving time. Statistical significant is appeared after 60 min in all parameters.

• 대한핵의학회:학술대회논문집
• /
• 1985.05a
• /
• pp.176.1-176.1
• /
• 1985

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2007.06a
• /
• pp.323-324
• /
• 2007

• The Korean Journal of Pharmacology
• /
• v.22 no.2
• /
• pp.115-122
• /
• 1986

To delineate the relationship between subtypes of central alpha-adrenoceptor and central calcium channel, influences of intracerebroventricular (icv) diltiazem and nifedipine on the changes of blood pressure and heart rate by icv methoxamine and clonidine were investigated in urethane-anesthetized rabbits. 1) Methoxamine (1mg, icv) produced pressor and bradycardiac effect and clonidine $(30\;{\mu}g,\;icv)$ produced hypotension and bradycardia. 2) Icv diltiazem and nifedipine elicited dose-dependent deprcssor and bradycardiac responses. The depressor response to nifedipine was more prominent than that to diltiazem but the bradycardiac effect of nifedipine was smaller than that of diltiazem. The depressor responses to icy nifedipine $(35{\mu}g)$ and icv diltiazem $(400{\mu}g)$ were persistent but those to intravenous (iv) nifedipine $(35{\mu}g/kg)$ and diltiazem $(200{\mu}g/kg)$ were transient. 3) The pressor response to methoxamine was little affected by pretreatment with in diltiazem $(400{\mu}g)$ or icv nifedipine $(35,\;350{\mu}g)$ but the bradycardiac response to methoxamine was significantly attenuated by the same pretreatment. 4) The depressor response to clonidine was markedly attenuated by pretreatment with icv diltiazem $(400{\mu}g)$ or icv nifedipine $(35,\;350{\mu}g)$ but not affected by pretreatment with iv diltiazem $(200{\mu}g/kg)$ or iv nifedipine $(20{\mu}g/kg)$. Pretreatment with icv and iv diltiazem or nifedipine reduced the bradycardiac effect of clonidine. 5) Pretreatment with icv clonidine had no effect on the depressor and bradycardiac responses to in diltiazcm or icv nifedipine. These results indicate that diltiazem and nifedipine have no effect on icv methoxamine-induced pressor response elicited by the activation of central alpha-l adrenoceptors whereas the icv clonidine-induccd depressor and bradycardiac effects which result from the activation of central alpha-2 adrenoceptors are inhibited by the calcium antagonists.

• KIPS Transactions on Software and Data Engineering
• /
• v.6 no.2
• /
• pp.91-102
• /
• 2017

Many of the wearable smart fitness devices provide services related to users' heartbeat rates. These services use fixed standards which have been pre-determined based on statistical data. However, because body conditions significantly differ between individuals, the services applying fixed standards to all individuals are not reliable. This paper proposes the Feedback-RFC model which adapts heartbeat standards to individual users' exercise abilities and also proposes a method to implement the model. This paper also shows the effectiveness of the Feedback-RFC model by collecting heartbeat data from 12 participants and evaluating the model with the data.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.1
• /
• pp.615-621
• /
• 2018

To enhance the energy saving and comfort of indoors, this study performed a stimulation of sound fluctuation, color temperature, and aroma. The experiment with EEG, HRV, and Vibra images was conducted in an environmental test room with a temperature of $25[^{\circ}C]$, relative humidity of 50[RH%], air current speed of 0.002[m/s], and illuminance of 1000[lux]. The stimulation experiment set up different sensory stimulation conditions, such as before exposure, single-sensory stimulation of fluctuation a=1.106 jazz music, single-sensory stimulation of RED color lighting, single-sensory stimulation of scent aroma, and multi-sensory stimulation of fluctuation a=1.106 jazz music, RED color lighting, and scent aroma. After the multi-sensory stimulation of fluctuation a=1.106 jazz music, RED color lighting and scent aroma, the capacity for work and attention were increased, and the stress index and fatigue degree were decreased. In addition, multi-sensory stimulation of fluctuation a=1.106 jazz music, RED color lighting, and scent aroma were effective in maintaining a stable heart and health. In addition, the Vibra image appeared to decrease tension/anxiety and stress. The multi-sensory stimulation of fluctuation a=1.106 jazz music, RED color lighting, and scent aroma help increase the Neuro-energy more than that by no exposure and single-sensory stimulation.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.52 no.9
• /
• pp.547-553
• /
• 2003

In this paper, we designed the PC-based analyzer of the power spectral density that could estimate the heart rate variability from time series data of R-R interval. The power spectral density estimated that it applied the autoregressive model to the measured electrocardiogram during a short period. Also, the characteristics of the designed analyzer are that it could process of the signal filtering, the generation and recomposition of time series and the feature extraction at the same time. Especially the analyzer reconstructed which applied the lowpass filter of the time series composed by the linear interpolation so as to enhance the signal-to-noise feature. We could estimate the power spectral density that confirmed a variety of power peak with low frequency range and high frequency rang of autonomic nerve by the heart rate variability.

• Proceedings of the KIEE Conference
• /
• 2002.07d
• /
• pp.2693-2695
• /
• 2002

In this paper, the power spectral analysis of heart rate variability(HRV) was performed to evaluate effects of orthostatic stress with head-up tilt on autonomic nervous system(ANS) for 20 healthy male subjects(age : 245 yr.) and a new method was proposed to assess the autonomic balance. The ECG signals wore recorded for 3 minutes in both the supine and 70 head-up tilt positions, and then the HRV signals underwent power spectrum analysis at each position. The results of this study suggest that cardiac autonomic functions, such as sympathetic tone in autonomic balance with the increment of sympathetic tone and the decrement of parasympathetic tone which occur during head-up tilt position, arc not sufficient to overcome tile orthostatic stress arising in Cerebral Palsy.

• Korean Journal of Psychosomatic Medicine
• /
• v.12 no.1
• /
• pp.3-14
• /
• 2004

In this article, the effects of stress on central nerve system and heart function and the concept of heart rate variability were reviewed. HRV(Heart Rate Variability), the periodical change of the heart rate, is indicated larger in the healthier because they respond flexibly to various sorts of facts influencing on HR. HRV analysis is largely composed of the time domain analysis and the frequency analysis. In the former the flexibility of heart function is analysed, while in the latter autonomic nerve function is examined, which is the degree of sympathetic and parasympathetic nerve activity and the state of balance. Furthermore, existence or nonexistence of disease and/or level of stress can be estimated by measuring the variability and normality of heart rate, and balance of autonomic nerve system, and through HRV biofeedback the symptoms of anxiety disorder or asthma can be reduced.

• The Journal of the Korea Contents Association
• /
• v.9 no.7
• /
• pp.225-232
• /
• 2009

This study conducted the following experiment to examine effects of cardiovascular function on lumbar stabilization exercise(LSE) in floor or swiss ball. This experiment was conducted to compare heart rate, systolic blood pressure, diastolic blood pressure and peripheral vascular oxygen saturation effects by lumbar stabilization exercise in floor or swiss ball with 18 normal adult and it divided 9 subjects. experiment group (1) is applying LSE on floor group and (2) is applying LSE on swiss ball group. Heart rate was measured by portable heart rate manometer, blood pressure was measured by hemodynamometer, and peripheral vascular oxygen concentration was measured using a computerized NURYTEC measuring apparatus analysis. These result lead us to the conclusion that systolic blood pressure and peripheral vascular oxygen concentration were influenced by LSE. but there was not differential effect between each groups. These results suggest that LSE has the capability to improve heart rate, blood pressure, peripheral vascular oxygen concentration. Consequently, LSE would be lead to increment of cardiovascular function.