• Journal of the Korean Society of Food Science and Nutrition
• /
• v.30 no.5
• /
• pp.854-857
• /
• 2001

Electron spin resonance (ESR) spectroscopy was used to detect free radicals in irradiated dried vegetables. Dried carrot, mushroom and green onion were irradiated with doses of 0, 1, 3, 5 and 7 kGy at room temperature using a Co-60 irradiator. Free radicals were detected in irradiated dried carrot, green onion and mushroom, while those were not detected in non-irradiated samples. Since concentration of free radicals linearly increased with applied doses (1~7 kGy), highly positive correlation coefficients ($R^2$=0.9747~0.9919) were obtained between irradiation doses and free radical concentrations right after irradiation. Although concentration of free radicals slowly decreased with storage time, the characteristic ESR signals of free radicals slowly decreased with storage time, the characteristic ESR signals of free radical in irradiated samples were observed even after 3 months of storage at room temperature.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.15 no.3
• /
• pp.527-532
• /
• 2020

In this paper, we presented the results of analysis through EEG measurement for the purpose of checking the frequency band of EEG signals that can be used for personal authentication. The measurement status was divided into the open-eye state and the closed-eye state depending on the presence or absence of an optical task. The data measured in the EEG experiments was divided into seven frequency bands : delta waves, theta waves, alpha waves, SMR waves, mid-beta waves, beta waves and gamma waves to identify the frequency band with the smallest power fluctuation over time. In our results, there was no significant difference between the open-eye state and the closed-eye state, and the SMR waves and mid-beta waves related to human concentration had the smallest fluctuation in power over time, and were a highly reproducible frequency band.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.05a
• /
• pp.958-961
• /
• 2015

Emotional expression is universal and emotional state impacts important areas in our life. Until now, analyzing the acquired EEG signals under circumstances caused by invoked feelings and efforts to define their emotional state have been made mainly by psychologists based on the results. But, recently emotion-related information was released by research results that it is possible to identify mental activity through measuring and analyzing the brain EEG signals. So, this study has compared and analyzed emotional expressions of human by using brain waves. To get EEG difference for a particular emotion, we showed specific subject images to the people for changing emotions that peace, joy, sadness and stress, etc. After measured EEG signals were converged into frequence domain by FFT signal process, we have showed EEG changes in emotion as a result of the performance analyzing each respective power spectrum of delta, theta, alpha, beta and gamma waves.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.05a
• /
• pp.951-953
• /
• 2015

Learning for thinking says the behavior of the organism changes as a result of practice or experience. It is very difficult to identify focusing ability objectively when students study. But, brain of the body is not so. EEG signal means continuously electric records of brain potential variation between two points on the scalp when brain activities take place. In types of EEG, there are delta(0~4Hz), theta(4~8Hz), alpha(8~13Hz), beta(13~30Hz) and gamma waves(30~50Hz). SMR waves and Mid-beta waves appear when focused for studying. Part for the most influence on concentrating reported that Mid-beta waves. In relation to brain activities, EEG has been actively researched for evaluating brain focus index system during learning and study. So, By using Biopac system for this study, measured brain wave was converted into FFT for extracting Mid-beta domain signals that are related to learning after giving focus invoked subjects to a small number of people. When concentrating, we measured the change in the power of the Mid-beta frequency domain and presented a correlation. Based on these results, we analyzed whether students are concentrated objectively on learning or not. and hope to offer more efficient learning method.

• Journal of Science Education
• /
• v.43 no.1
• /
• pp.157-172
• /
• 2019

The purpose of this study is to analyze the influence of number of targets on common knowledge generation and brain activity during the common life science discovery task performance. In this study, 35 preliminary life science teachers participated. This study was intentionally made a block designed for EEG recording. EEGs were collected while subjects were performing common discovery tasks. The sLORETA method and the relative power spectrum analysis method were used to analyze the brain activity difference and the role of activated cortical and subcortical regions according to the degree of difficulty of common discovery task. As a result of the study, in the case of the Theta wave, the activity of the Theta wave was significantly decreased in the frontal lobe and increased in the occipital lobe when the difficult difficulty task was compared with the easy difficulty task. In the case of Alpha wave, the activity of Alpha decreased significantly in the frontal lobe when performing difficult task with difficulty. Beta wave activity decreased significantly in the frontal lobe, parietal lobe, and occipital lobe when performing difficult task. Finally, in the case of Gamma wave, activity of Gamma wave decreased in the frontal lobe and activity increased in the parietal lobe and temporal lobe when performing the difficult difficulty task compared to the task of easy difficulty. The level of difficulty of the commonality discovery task is determined by the cingulate gyrus, the cuneus, the lingual gyrus, the posterior cingulate, the precuneus, and the sub-gyral where it was shown to have an impact. Therefore, the difficulty of the commonality discovery task is the process of integrating the visual information extracted from the image and the location information, comparing the attributes of the objects, selecting the necessary information, visual work memory process of the selected information. It can be said to affect the process of perception.

• Science of Emotion and Sensibility
• /
• v.16 no.3
• /
• pp.387-396
• /
• 2013

In this study, the influence of classroom smells (foot odor, hair smell, sour smell, and sweat smell) of male high school and sweat smell and the offensive odor substance (ammonia and butyric acid) on the electroencephalography (EEG) activities of 20 female volunteers, ranging in age from 30 to 50 were studied. The representative response of brainwave index by these smells stimuli was most pronounced on temporal lobes among the brain lobes. By comparison with background EEG activities on temporal lobes, the smells reduced the relative alpha band power (0.04~0.13) and increased the relative beta band power (0.02~0.06) and the relative gamma band power (0.03~0.09). The alpha wave was deactivated, high beta (18~30Hz) and gamma (30~50Hz) waves were remarkably activated. The order of EEG fluctuation caused by the smell stimulus is as follows; hair smell > butyric acid > foot odor, sour smell > ammonia > sweat smell. It means that the classroom smells cause an excessive brain arousal and straining and may be reducing one's attention and learning ability.

• The Journal of Engineering Geology
• /
• v.27 no.3
• /
• pp.323-330
• /
• 2017

For the formation identification, surface geological survey, drill core analysis, core description and well log analysis are widely used. Among them well log analysis is a popular method with drill core analysis, since it measures continuously physical properties at in-situ. In this study we calculated Thomsen anisotropic parameters (${\varepsilon},\;{\delta},\;{\eta}$) after applying Backus averaging method to the P wave velocity, S wave velocity, and density logs. The well log data application of Blackfoot, Canada, shows the formation could be divided by 12 layers. This shows that Thomsen anisotropic parameters for identifying formation using anisotropic parameters is useful if there is no natural gamma log that is widely used for the formation identification.

• Sleep Medicine and Psychophysiology
• /
• v.10 no.2
• /
• pp.100-107
• /
• 2003

Objectives: Periodic leg movements in sleep (PLMS) might be subdivided based upon whether or not they are associated with visible EEG microarousals (MA). MA is considered to be responsible for nonrestorative sleep and daytime fatigue. The American Sleep Disorders Association's (ASDA) scoring rules for MA based on visual analysis of the EEG changes suggest that MA should last more than 3 seconds. However, it has been suggested that visual analysis may not detect some changes in EEG activity. This study is aimed at measuring changes in EEG spectra during PLMS without MA in order to better understand the arousing response of PLMS. Methods: Ten drug-free patients (three men and seven women) diagnosed with PLMS by polysomnography were studied. Spectral analysis of the EEG was performed in each patient on 30 episodes of PLMS without MA, chosen randomly across the night in stage 2 non-REM sleep. We applied stricter criteria for MA compared to ASDA, by defining it as a return to alpha and theta frequency lasting at least 1 second. Results: The mean PLMS index was $16.7{\pm}10.0$. The mean PLMS duration was $1.3{\pm}0.7$ seconds. Comparison of 4-second EEG activity both before and after the onset of PLMS without MA using independent t-test showed that the movements were associated with significant increase of relative activity in the delta band (p=0.000) and significant decrease of activity in the alpha (p=0.01) and sigma (p=0.000) bands. No significant decrease in the theta (p=0.05), beta (p=0.129), or gamma (p=0.062) bands was found. Conclusion: PLMS without MA was found to be associated with EEG change characterized by increase in the delta frequency band. This finding seems to be compatible with the hypothesis of an integrative hierarchy of arousal responses of Sforza's. Considering that the subjects had lower PLMS index and shorter PLMS duration than those of the previous study, it is suggested that an even less severe form of PLMS without MA could induce neurophysiologic change, which may potentially be of clinical significance.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.14 no.1
• /
• pp.127-132
• /
• 2010

Purpose: Because of limitation of image acquisition method and acquisition time, scatter correction cannot perform easily in SPECT study. But in our hospital, could provide to clinic doctor of scatter corrected images, through introduction of new generation gamma camera has function of simple scatter correction. Taking this opportunity, we will compare scatter corrected and non-scatter corrected image from image quality of point of view. Materials and Methods: We acquisite the 'Hoffman brain phantom' SPECT image and '1mm line phantom' SPECT image, each 18 times, with GE Infinia Hawkeye 4, SPECT-CT gamma camera. At first, we calculated each contrast from axial slice of scatter corrected and non-scatter corrected SPECT image of 'Hoffman brain phantom'. and next, calculated each FWHM of horizontal and vertical from axial slice of scatter corrected and non-scatter corrected SPECT image of '1mm line phantom'. After then, we attempted T test analysis with SAS program on data, contrast and resolution value of scatter corrected and non-scatter corrected image. Results: The contrast of scatter corrected image, elevated from 0.3979 to 0.3509. And the resolution of scatter corrected image, elevated from 3.4822 to 3.6375. p value were 0.0097 in contrast and <0.0001 in resolution. We knew the fact that do improve of contrast and resolution through scatter correction. Conclusion: We got the improved SPECT image through simple and easy way, scatter correct. We will expect to provide improved images, from contrast and resolution point of view. to our clinic doctor.

• Journal of Food Hygiene and Safety
• /
• v.4 no.2
• /
• pp.119-132
• /
• 1989

Gamma irradiation as a new physical treatment was applied to comparative investigates with a conventional ethylene oxide fumigant on the microbiological and physicochemical qualities of selected spices and dry vegetables such as powdered red pepper, black pepper, welsh onion, onion, garlic, carrot, korean cabbage and instant ramyon soup. The microorganisms contaminated in the sample, including total viable count, thermophilic bacteria, aerobic spore and fungi counts between the $10^4\;to\;10^6/g$ range. Coliforms were found only in black pepper and welsh onion powder as the $10^2\;to\;10^3/g$ level. A radiation dose of 7 to 10 KGy were sterilized completely to the contaminated microorganisms, while ehthylene oxide (E.O.) fumigation reduced of them to the $10^3/g$ level. An optimum dose of irradiation was less detrimental than E.O. fumigation to the physicochemical properties of the sample. Sensory evaluation after three months of storage at room temperatures showed that the overall acceptability of irradiated sample was higher than that of the non treated control as well as E.O. fumigated samples. Comparison gamma irradiation with E.O. gas treatment showed that E.O. treatment was less effective than radiation in cotrolling microbial contamination of spices and vegetables.