• Animal Systematics, Evolution and Diversity
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• v.38 no.1
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• pp.14-19
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• 2022

Leptochiton Gray, 1847 is one of the most ancient chiton groups which includes more than 130 species that occur in cold and deep waters worldwide. Due to their small-sized body, they are often confused as juveniles of other chiton species. Moreover, lack of morphological information makes species identification of this group very challenging. To date, only two Leptochiton species(L. fuliginatus and L. rugatus) have been reported from Korean waters. In this study, we found L. hakodatensis(Thiele, 1909) for the first time in Korea and described microscopic morphological characters of valves (tegmentum sculpture), girdle scale, and radula using a scanning electron microscopy (SEM). Leptochiton hakodatensis is morphologically similar to L. fuliginatus and L. rugatus, but differently characterized by having dorso-ventrally rounded (not carinated) intermediate valves, girdle (perinotum) scales sculptured with 4-7 longitudinal ribs, and bicuspid major lateral teeth of radula. In addition to morphological examination, we determined the partial mitochondrial cytochrome c oxidase subunit I(cox1) as a DNA barcode sequence information. This is the first report that describes microscopic characters (tegmentum of valves, girdle structure, and radula) of L. hakodatensis using a SEM. This study provides a morphological basis for describing Leptochiton species and discovery of a "hidden" species of this genus.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.205-205
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• 2021

Surface soil moisture, which governs the partitioning of precipitation into infiltration and runoff, plays an important role in the hydrological cycle. The assimilation of satellite soil moisture retrievals into a land surface model or hydrological model has been shown to improve the predictive skill of hydrological variables. This study aims to improve streamflow prediction with Weather Research and Forecasting model-Hydrological modeling system (WRF-Hydro) by assimilating Soil Moisture Active and Passive (SMAP) data at 3 km and analyze its impacts on hydrological components. We applied Cumulative Distribution Function (CDF) technique to remove the bias of SMAP data and assimilate SMAP data (April to July 2015-2019) into WRF-Hydro by using an Ensemble Kalman Filter (EnKF) with a total 12 ensembles. Daily inflow and soil moisture estimates of major dams (Soyanggang, Chungju, Sumjin dam) of South Korea were evaluated. We investigated how hydrologic variables such as runoff, evaporation and soil moisture were better simulated with the data assimilation than without the data assimilation. The result shows that the correlation coefficient of topsoil moisture can be improved, however a change of dam inflow was not outstanding. It may attribute to the fact that soil moisture memory and the respective memory of runoff play on different time scales. These findings demonstrate that the assimilation of satellite soil moisture retrievals can improve the predictive skill of hydrological variables for a better understanding of the water cycle.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.28.3-29
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• 2021

Galaxies are not just randomly distributed in space; instead, a variety of galaxy alignments have been found over a wide range of scales. Such alignments are the outcome of the combined effect of interacting neighbors and the surrounding large-scale structure. Here, we focus on the spin-orbit alignment (SOA) of galaxy pairs, the dynamical coherence between the spin of a target galaxy and the orbital angular momentum of its neighbor. Based on a recent cosmological hydrodynamic simulation, the IllustrisTNG project, we identify paired galaxies with mass ratios from 1/10 to 10 at z = 0 and statistically analyze their spin-orbit angle distribution. We find a clear preference for prograde orientations (i.e., SOA), which is more prominent for closer pairs. The SOA is stronger for less massive targets in lower-density regions. The SOA witnessed at z = 0 has been developed progressively since z = 2. There is a clear positive correlation between the alignment strength and the interaction duration with its current neighbor. Our results suggest the scenario in which the SOA is developed mainly by interactions with a neighbor for an extended period of time, rather than by the primordial torque exerted by the large-scale structure.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.32.1-32.1
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• 2021

We present the magnetic field strengths of CTA 102 using multi-frequency data at 2.6-343.5 GHz in order to study the physical origins of radio flares. The observations at 22 and 43 GHz were conducted using the single-dish radio telescopes of the Korean VLBI Network (KVN) from December 2012 until May 2018 (MJD 56200-58400). We used multi-frequency data obtained from the Effelsberg 100-m, OVRO 40-m, Metsähovi 14-m, IRAM 30-m, SMA, ALMA, and VLBA telescopes. During the period of the observations, two major flares (R1 and R2) are seen clearly at 15 and 37 GHz during MJD 57500-57800 and MJD 58000-58300, respectively. The source shows typical variability with time-scales ranging from 20-161 days at 15 GHz. The variability Doppler factor is in the range of 11.51-31.23. The quasi-simultaneous radio data are used to investigate the synchrotron spectrum of the source, finding that the synchrotron radiation is self-absorbed. The turnover frequency and the peak flux density of the synchrotron self-absorption (SSA) spectra are in ranges of 38.06-167.86 GHz and 1.49-10.38 Jy, respectively. From the SSA spectra, magnetic field strengths are estimated to be < 10 mG. The equipartition magnetic field strengths are larger than the SSA magnetic field strengths by a factor of > 100. This indicates that the radio flares may be related to a particle energy-dominated emission region.

• Korean Journal of Childcare and Education
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• v.18 no.6
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• pp.75-99
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• 2022

Objective: This study aims to explore ways to empirically analyze and manage childcare teachers' job stress based on their relationship with stress-related physiological indicators measured by a fitness tracker. Methods: The study participants were 27 childcare teachers in Gyeonggi-do and wore Garmin's wearable fitness tracker Vivosmart 4 for 15 days for three months. The collected information was analyzed for mean, SD, ANOVA, and correlation using JAMOVI 2.00. Results: First, among the daily changes of physiological indicators measured by a fitness tracker, the data collected on Mondays were significant. On Mondays, the stress index was high, the duration of the rest period was short, and the sleep time was short. The stress of childcare teachers showed a significant negative relationship with the body battery which was calculated by considering the duration of the rest period, heart rate variability, stress, and activity level. Also, the duration of deep sleep was positively correlated with a low degree of stress. There was a significant relationship between the childcare teachers' psychological indicators and the biomarkers measured by fitness trackers. Conclusion/Implications: Stress research using a fitness tracker is big data, and in-depth analysis is possible. Fitness trackers can collect and utilize repeated measurement data for each individual childcare teacher.

• New & Renewable Energy
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• v.20 no.1
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• pp.79-87
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• 2024

This study introduces a method for estimating Aerosol Optical Depth (AOD) using Broadband Aerosol Optical Depth (BAOD) derived from direct normal irradiance and meteorological factors observed between 2016 and 2017. Through correlation analyses between BAOD and atmospheric components such as Rayleigh scattering, water vapor, and tropospheric nitrogen dioxide, significant relationships were identified, enabling accurate AOD estimation. The methodology demonstrated high correlation coefficients and low Root Mean Square Errors (RMSE) compared to actual AOD₅₀₀ measurements, indicating that the attenuation effects of water vapor and the direct impact of tropospheric nitrogen dioxide concentration are crucial for precise aerosol optical depth estimation. The application of BAOD for estimating AOD₅₀₀ across various time scales-hourly, daily, and monthly-showed the approach's robustness in understanding aerosol distributions and their optical properties, with a high coefficient of determination (0.96) for monthly average AOD₅₀₀ estimates. This study simplifies the aerosol monitoring process and enhances the accuracy and reliability of AOD estimations, offering valuable insights into aerosol research and its implications for climate modeling and air quality assessment. The findings underscore the viability of using BAOD as a surrogate for direct AOD₅₀₀ measurements, presenting a promising avenue for more accessible and accurate aerosol monitoring practices, crucial for improving our understanding of aerosol dynamics and their environmental impacts.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.9
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• pp.2642-2664
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• 2024

In the process of modern traffic management, information technology has become an important part of intelligent traffic governance. Real-time monitoring can accurately and effectively track and record vehicles, which is of great significance to modern urban traffic management. Existing tracking algorithms are affected by the environment, viewpoint, etc., and often have problems such as false detection, imprecise anchor boxes, and ID switch. Based on the YOLOv5 algorithm, we improve the loss function, propose a new feature extraction module to obtain the receptive field at different scales, and do adaptive fusion with the SGE attention mechanism, so that it can effectively suppress the noise information during feature extraction. The trained model improves the mAP value by 5.7% on the public dataset UA-DETRAC without increasing the amount of calculations. Meanwhile, for vehicle feature recognition, we adaptively adjust the network structure of the DeepSort tracking algorithm. Finally, we tested the tracking algorithm on the public dataset and in a realistic scenario. The results show that the improved algorithm has an increase in the values of MOTA and MT etc., which generally improves the reliability of vehicle tracking.

• Nuclear Engineering and Technology
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• v.56 no.10
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• pp.4355-4364
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• 2024

Fluid pipelines, commonly utilized in the oil industry, often face efficiency and reliability issues due to sediment buildup causing erosion, corrosion, and pipe wall thinning. Traditional assessment methods involve disruptive measures like cutting or creating holes and temporarily taking pipelines out of service. A non-destructive alternative, Limited-Number-Detector Computed Tomography (LNDCT), proves cost-effective and superior. Our proposed algorithm enhances data acquisition and projections using discrete detectors, employing Co-60 as a gamma-ray source and thallium-doped sodium iodide, NaI(Tl), detectors in an arc configuration. Monte Carlo simulations aligned closely with experimental data. Optimization involved adjusting the detector aperture angle based on a primary-to-scatter ratio of gamma-ray photons. We investigated the utility of various isotopes (Co-60, Cs-137, Am-241, Ir-192) to determine optimal projection signal amplitude. The algorithm generates a large sinogram matrix, and a filtered back-projection algorithm with a Hamming filter maximizes image quality while ensuring acceptable calculation volume and time. Using four phantoms, including pipelines filled to different scales, our study evaluates LNDCT configuration, performance, and validation. The results highlight its potential for efficiently evaluating sediment in pipelines, confirming the correctness and accuracy of our proposed algorithm.

• Sleep Medicine and Psychophysiology
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• v.13 no.2
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• pp.67-74
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• 2006

Introduction: Excessive daytime sleepiness and cataplexy are key features of narcolepsy. Modafinil is psychostimulant used in the treatment of narcolepsy. In this study, we evaluated effects of modafinil on nocturnal sleep structure and sleep latency in multiple sleep latency test and clinical features. Methods: Twelve narcoleptic patients (7 male, age: $22.9{\pm}2.6\;yrs$) were participated in the study. All of them had done nocturnal polysomnography (nPSG), multiple sleep latency test (MSLT), clinical symptoms scales and have repeated same procedure after taking 200 mg of modafinil. We have done linear mixed model analysis to describe effects of group, medication and nap time on these measures. Results: Modafinil did not affect clinical scales except PSQI which had been reduced after medication. In this study, Modafinil reduced total sleep time, sleep efficiency and increased wake after sleep onset and percent of arousal during sleep in nocturnal polysomnography and prolonged mean sleep latency in multiple sleep latency tests in both group. Discussion: Modafinil has stimulant effect of central nervous system but its effect on night sleep is less than other psychostimulants such as methylphenidate. We ascertained that modafinil affected total sleep time, sleep efficiency and percent of wake during sleep but did not effect on sleep structure. Modafinil was effective in the management of day time sleepiness. Modafinil can enhance alertness of control group without day time sleepiness.

• Animal Systematics, Evolution and Diversity
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• v.5 no.1
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• pp.77-88
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• 1989

Genetic and morphometric comparison between two species of the genus Agkistrodon were performed to estimate the degree of genic variation and to clarify the taxonomic status of Cheju population, a suspected hybrid form between A. blomhoffii brevicaudus and A u ussuriensis. A sum of 147 specimens representing six populations of A.b. brevicaudus and two populations of A ussuriensis was used in this study. Out of the 21 loci examined, 5 loci (Adh, Ldh-2, Mdh-2, Mpi, Pgi) were monomorphic with identical mobility in both species. O Other Sioci (Aco, Gp, Fum, [po and Xdh in A b. brevicaudus; Est, Got-l, Gp, Mdh-l and 6Pgd in A ussuriensis) were highly poplymorphic. The degree of genic variation of Ab. b brevicaudus and A ussuriensis was A=1.SS, P=42.1%, HD=0.096, HG=O.l1S, and A= 1.4S, P = 31.6%, HD=0.117, HG =0.121, repectively. These values are twofold higher t than those of other reptilian species reported (Selander, 1976) including Korean species of Rhabdophis tigrina and Elaphe dione (Paik and Yang, 1986, 1987). The average values of t the genetic similarities among six populations of A b. brevicaudus and two populations of A ussuriensis were S=0.919 and S=0.962, respectively, whereas the value between species was S = 0.662. Presumed divergent time estimate (Nei, 1975) of these two species was about 1 1.8 million years ago. The analysis of the geographic variations of various morphological c characters was based on Gloyd’s criteria (Gloyd, 1972). Coloration of tongue and tail tip, t the number of ventral scales, and the number of subcaudal scales are good diagnostic c characters to identify these two species. The pattern of cross band is, however, highly variable within and between populations of both species. No hybrid was detected and the s suspected hybrid form of Cheju population falls within the range of A. ussuriensis in the g genetic and morphometric analyses.