• Journal of Bio-Environment Control
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• v.26 no.2
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• pp.123-132
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• 2017

This study was aimed to investigate the effect of 1)irradiation with several different ratios using red, green, and blue LEDs and 2)various pulsed light irradiation with 50% duty ratio using red and blue LEDs on the growth and morphogenesis of three lettuce cultivars (Lactuca sativar L. cv. 'Jukchukmeon', 'Lolo Rosa', and 'Grand Rapid') in hydroponics culture system for 4 weeks after transplanting. Seeds were sown in rock-wool plug trays and they were placed in a culture room which was controlled at $23{\pm}1^{\circ}C/18{\pm}1^{\circ}C$ temperature and 50-60/70-85% for day and night, respectively, during cultivation period. Irradiated RGB ratios with LEDs were 6:3:1, 5:2.5:2.5, 3:3:4, 2:2:6, and 1:1:8 with $110{\pm}3{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD on the surface of cultivation bed. The frequencies of pulsed lighting was 50, 100, 500, 1,000, 5,000, 10,000, 25,000Hz (20, 10, 0.1, 0.04 ms) with red and blue LEDs and 50% duty ratio. At the RGB ratio of 6:3:1, the average fresh weight of 'Jukchukmeon' was significantly higher than that of other RGB treatments, but no significant difference compared to the fluorescent treatment. The average fresh weight at 1:1:8 RGB ratio in 'Lolo Rosa' was significantly lower than that of other RGB treatments. Leaf number and fresh weight of 'Grand Rapid' were significantly lower in the control and 1:1:8 RGB treatments, compared to the other RGB treatments. As the ratio of blue light increased, leaf length decreased and leaf shape became round in three lettuces. Although there is little change in growth, it could not be found any tendency to affect the growth and morphogenesis of three lettuces caused by increasing or decreasing frequency of pulsed lighting with 50% duty ratio at the $72{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.126-134
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• 2017

There have been numerous studies on extracting the R-peak from electrocardiogram (ECG) signals. However, most of the detection methods are complicated to implement in a real-time portable electrocardiograph device and have the disadvantage of requiring a large amount of calculations. R-peak detection requires pre-processing and post-processing related to baseline drift and the removal of noise from the commercial power supply for ECG data. An adaptive filter technique is widely used for R-peak detection, but the R-peak value cannot be detected when the input is lower than a threshold value. Moreover, there is a problem in detecting the P-peak and T-peak values due to the derivation of an erroneous threshold value as a result of noise. We propose a robust R-peak detection algorithm with low complexity and simple computation to solve these problems. The proposed scheme removes the baseline drift in ECG signals using an adaptive filter to solve the problems involved in threshold extraction. We also propose a technique to extract the appropriate threshold value automatically using the minimum and maximum values of the filtered ECG signal. To detect the R-peak from the ECG signal, we propose a threshold neighborhood search technique. Through experiments, we confirmed the improvement of the R-peak detection accuracy of the proposed method and achieved a detection speed that is suitable for a mobile system by reducing the amount of calculation. The experimental results show that the heart rate detection accuracy and sensitivity were very high (about 100%).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.3
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• pp.93-105
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• 1993

In this paper, the maximum scour depths at piers located in the Bo Cheong Stream, which is a tributary in the Geum River System, were calculated and compared using 24 local pier scour equations. The equations were classified as six groups by non-dimensional types of equations. The geometric data in the stream bed and pier data at San Seong, Yi Pyung and San Gye, which are IHP data collection stations, were utilized for applying the scour equations. The geometric data in the stream bed were obtained by analyzing the bed material sampled in three stations which are in the left side, middle and right side for stream direction. The maximum flow velocities at maximum flow depths which were measured from 1982 to 1991, were used as the hydraulic flow data. The pier data for predicting pier scour depths were measured in the fields. The maximum pier scour depths calculated using the equations were compared with the held scour depths measured in the streams or rivers in the world. Arunachalam, Shen-Karaki III, Jain-Fischer equations are selected as the proper local scour equations for predicting the maximum local scour depths at piers in the Bo Cheong Stream. Inglis-Lacey and Shen-Karaki II equations are applicable in case of rapid flows conditions in which Froude number is over 0.3. Froehlich, Laursen I, Laursen II, Neill, Melville equations are applicable in the slow flow conditions in which Froude number is less than 0.3. Blench equation or Inglis-Poona equation varies rapidly by changing Froude numbers. Therefore the equations should not be used without careful considerations in selecting the applicable ranges. The maximum local scour depths calculated using Sarma-Krishnamurthy, Ahmad, Coleman, Varzeliotis, Larras, Bata, Chitale, Venkatadri, Basik-Basamily-Ergun, U.S.G.S., Shen I equations are usually less than the scour depths measured in the fields.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.4
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• pp.206-216
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• 2017

The temporal distribution of the turbulence kinetic energy (TKE) and the vertical component of Reynolds stresses ($-{\bar{u^{\prime}w^{\prime}}}$) was measured during one wave period under high wave energy conditions. The wave data were obtained at Hujeong Beach in the east coast of Korea at January 14~18 of 2017 when an extratropical cyclone was developed in the East Sea. Among the whole thousands of waves measured during the period, hundreds of regular waves that had with similar pattern were selected for the analysis in order to give three representing mean wave patterns using the ensemble average technique. The turbulence properties were then estimated based on the selected wave data. It is interesting to find out that $-{\bar{u^{\prime}w^{\prime}}}$ has one clear peak near the time of flow reversal while TKE has two peaks at the corresponding times of maximum cross-shore velocity magnitudes. The distinguished pattern of Reynolds stress indicates that vertical fluxes of such properties as suspended sediments may be enhanced at the time when the horizontal flow direction is reversed to disturb the flows, supporting the turbulence convection process proposed by Nielsen (1992). The characteristic patterns of turbulence properties are examined using the CADMAS-SURF Reynolds-Averaged Navier-Stokes (RANS) model. Although the model can reasonably simulate the distribution of TKE pattern, it fails to produce the $-{\bar{u^{\prime}w^{\prime}}}$ peak at the time of flow reversal, which indicates that the application of RANS model is limited in the prediction of some turbulence properties such as Reynolds stresses.

• Economic and Environmental Geology
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• v.49 no.5
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• pp.381-388
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• 2016

The purpose of this study is to integrate and visualize using mapping techniques based on precise seabed geomorphology, seafloor backscattering images and high-resolution underwater images of the nearshore area around the Dokdo, in the East Sea. We have been obtained the precise topography map using multibeam echosounder system around the nearshore area(~50 m) of the southern part of the Seodo. Side scan sonar survey for analysis seafloor backscattering images was carried out in the same area of topography data. High-resolution underwater images(zone(a), zone(b), zone(c)) were taken in significant habitat scope of the nearshore area of the southern part of the Seodo. Using the results of bathymetry, seafloor backscattering images, high-resolution underwater images, we performed an integrated visualization about the nearshore area of the Dokdo. The integrated visualizing techniques are possible to make the seabed characteristic mapping results of the nearshore area of the Dokdo. The integrated visualization results present more complex and reliable information than separate geological products for seabed environmental mapping study and it is useful to understand the relation between seafloor characteristics and topographic environments of the study area. The integrated visualizing techniques and mapping analysis need to study sustainably and periodically, for effective monitoring of the nearshore ecosystem of the Dokdo.

• Journal of the Korean Society of Radiology
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• v.14 no.4
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• pp.467-475
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• 2020

The purpose of this study is to assess doses to ¹⁸F-FDG, a radioactive drug, during PET examinations, to alleviate anxiety about radiation in patients and carers, to minimize the indiscriminate examination progress caused by medical institution personnel and space clearance problems, and health examination. The dose assessment was measured using a thermo-fluorescent dosimeter (TLD) and an electronic personal dosimeter (EPD) at the location of the cervical (hypothyroid), thorax (heart), and lower abdomen (breeding line) which are the three highest tissue areas of the radiation tissue weighting. In addition, spatial dose rates and radioactivity in urine were measured using GM counters and ion boxes. The results are as follows: First, the personal dosimeter TLD was measured 0.0425±0.0277 mSv in the cervical region, 0.0440±0.0386 mSv in the thorax and 0.0485±0.0436 mSv in the lower abdomen, with little difference in the heart dose depending on radiation sensitivity. The EPD was measured at 0.942±0.141 mSv/h immediately after the cervical position, and 0.192±0.031 mSv/h after 120 minutes. Immediately after the thorax position, 0.516±0.085 mSv/h, 120 minutes later 0.128±0.040 mSv/h. Immediately after the lower abdomen position, 0.468±0.091 mSv/h, and after 120 minutes 0.105±0.021 mSv/h were measured. The spatial dose rate at the GM counter was measured immediately at 0.041±0.005 mSv/h, 120 minutes later at 0.014±0.002 mSv/h. The radioactivity in urine using ion chamber was measured at 0.113±0.24 MBq/cc after 60 minutes and 0.063±0.13 MBq/cc after 120 minutes. As a result, ¹⁸F-FDG should be administered, dose re-evaluated two hours after the PET test is completed, and caregivers should be avoided. In addition, it is deemed necessary to provide patients and carers with sufficient explanations and expected values of exposure dose to avoid reckless testing. It is hoped that the data tested in this study will help patients and families relieve anxiety about radiation, and that the radiation workers' exposure management system and institutional improvements will contribute to the development of medical radiation.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.5
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• pp.401-409
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• 2008

Purpose: Recently multi-modal imaging system has become widely adopted in molecular imaging. We tried to fabricate animal-specific positioning molds for PET/MR fusion imaging using easily available molding clay and rapid foam. The animal-specific positioning molds provide immobilization and reproducible positioning of small animal. Herein, we have compared fiber-based molding clay with rapid foam in fabricating the molds of experimental animal. Materials and Methods: The round bottomed-acrylic frame, which fitted into microPET gantry, was prepared at first. The experimental mice was anesthetized and placed on the mold for positioning. Rapid foam and fiber-based clay were used to fabricate the mold. In case of both rapid foam and the clay, the experimental animal needs to be pushed down smoothly into the mold for positioning. However, after the mouse was removed, the fabricated clay needed to be dried completely at $60^{\circ}C$ in oven overnight for hardening. Four sealed pipet tips containing $[^{18}F]FDG$ solution were used as fiduciary markers. After injection of $[^{18}F]FDG$ via tail vein, microPET scanning was performed. Successively, MRI scanning was followed in the same animal. Results: Animal-specific positioning molds were fabricated using rapid foam and fiber-based molding clay for multimodality imaging. Functional and anatomical images were obtained with microPET and MRI, respectively. The fused PET/MR images were obtained using freely available AMIDE program. Conclusion: Animal-specific molds were successfully prepared using easily available rapid foam, molding clay and disposable pipet tips. Thanks to animal-specific molds, fusion images of PET and MR were co-registered with negligible misalignment.

• Korean Journal of Food Science and Technology
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• v.41 no.3
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• pp.302-306
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• 2009

The principal objective of this investigation was to identify adequate species for the harvest of Perilla frutescens leaves, which provide profound antioxidant activities, and harbor abundant caffeic acid and rosmarinic acid. Namchun, Donggeul-2, Bora, Sae-bora and Neul-bora variants of the plant were assessed herein. In this study, we evaluated the antioxidant effects of these plants, and utilized an HPLC system to verify their caffeic acid and rosmarinic acid contents. Dried Perilla frutescens leaves were boiled at a temperature of $100^{\circ}C$ for three hours, and were lyopholized in a freezedryer. The extracts were then processed in order to confirm their antioxidant activities via 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging activity assay, ferric-reducing antioxidant power (FRAP) assay, total flavonoid content and total polyphenol content assays. According to the observed antioxidant results of the five tested species of Perilla frutescens leaves, Bora and Donggeul-2 were shown to have more potent antioxidant activities than the other tested variants. The scavenge 50% of DPPH radical ($SC_50$ of DPPH) values were 241 ${\mu}g$ DM/mL in Donggeul-2 and 261 ${\mu}g$ DM/mL in Bora. Based on the results of the FRAP assay, the Bora variant showed a value of 796 mM $FeSO_4$ $7H_2O/g$ DM, and Donggeul-2 exhibited a value of 748 mM $FeSO_4$ $7H_2O/g$ DM, of which the total polyphenol contents were measured as 69.4 g GAE/kg DM and 61.8 g GAE/kg DM, respectively. Moreover, the Bora variant had the highest level of caffeic acid, and Donggeul-2 showed the highest rosmarinic acid content among the tested samples (0.87 mg/100 g wet base and 121 mg/100 g wet base, respectively). According to the results of this experiment, we selected two species, Bora and Donggeul-2, which were both verified to contain adequate and favorable antioxidant activities.

• Journal of Life Science
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• v.21 no.6
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• pp.796-804
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• 2011

Microglia are central nervous system (CNS)-resident professional macrophages that function as the principal immune cells responding to pathological stimulations in the CNS. Activation of microglia, induced by various pathogens, protects neurons and maintains homeostasis in the CNS, but severe activation causes inflammatory responses secreting various neurotoxic molecules such as nitric oxide (NO), prostaglandin $E_2$ ($PGE_2$) and pro-inflammatory cytokines. Allium fistulosum, a member of the onion family, is mainly cultivated for consumption, as well as medicinal use in Oriental medicine. It has been reported that A. fistulosum has various biological effects such as anti-oxidant, anti-platelet aggregation, anti-fungus and anti-cholesterol synthesis, however there has been no research about the anti-inflammatory effects of A. fistulosum extracts. In this study, it was undertaken to explore the functions of A. fistulosum as a suppressor of neuronal inflammation by using BV2 microglia cells. As a result, it was found that four kinds of extracts of A. fistulosum effectively reduced the expressions of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) at both mRNA and protein levels, and also attenuated pro-inflammatory cytokines such as tumor necrosis alpha (TNF-${\alpha}$), interleukin-$1{\beta}$ (IL-$1{\beta}$) and interleukin-6 (IL-6) at the mRNA level in BV2 stimulated by lipopolysaccharide (LPS). In addition, the extracts of A. fistulosum attenuated the release of NO markedly, as well as resulting in slight decreases of TNF-${\alpha}$ and IL-6 production, the effects of which were most significant when treated with ethyl alcohol extract from the whole A. fistulosum. In conclusion, the data indicated that the anti-inflammatory actions of A. fistulosum against BV2 microglia cells is through the down-regulation of iNOS, COX2 and pro-inflammatory cytokines such as TNF-${\alpha}$ and IL-6, and these effects are expected to help in the protection of nerve tissues by suppressions of neuronal inflammation in various neurodegenerative diseases.

• Korean Journal of Ecology and Environment
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• v.44 no.4
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• pp.327-336
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• 2011

Temporal and spatial variations of primary productivity were investigated in the estuary of Youngsan River and Mokpo coastal areas in 2009. After heavy rain, concentrations of ammonium, phosphate, and silicate increased at six stations in August. The torrential rainfall may cause an increase in nutrient concentrations during summer. There is no limitation of nutrients (except for February at the mid-Youngsan estuarine region YS2) but a potential phosphate limitation was apparent at all stations. Silicate depletion was observed at YS2 in February due to a massive diatom bloom. The trophic status of the Youngsan estuary and Mokpo coastal areas were inferred from an assessment of the primary productivity. In February and May, YS1 (upper Youngsan estuary site) and YS2, YS3 (near the Youngsan river estuary barrage), MP1 (upper Mokpo coastal region site) were appropriately assigned to the mesotrophic category. MP2 (mid-Mokpo coastal region site) and MP3 (outer site of Mokpo coastal region) were assigned to the oligotrophic category. All stations were classified to the oligotrophic status in November. In August, after heavy rain, Youngsan estuary stations maintained mesotrophic status. On the other hand, MP1 and MP2 were classified in the eutrophic category and MP3 to mesotrophic status. In particular, primary productivities of MP1 and MP2 were 9 and 7 times higher respectively than the standard of eutrophic status ($1,000-mgC\;m^{-2}d^{-1}$). These results suggest that a massive freshwater discharge from the Youngsan River estuary should be considered a main factor in the occurrence of phytoplankton bloom in Mokpo coastal areas during summer. Seasonal variations of primary productivity are closely related with depth-integrated Chl. a.