• Journal of the Korea Society for Simulation
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• v.26 no.3
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• pp.73-86
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• 2017

Environmental data plays an important role to enhance the reliability of experimental results in M&S(Modeling and Simulation). Especially in Military M&S, extreme weather events can be used for virtual training and simulation importantly. However, the environmental data is huge and it is dispersed among multiple organizations. It is difficult for M&S operators to select the date and area where the weather phenomenon occurs in the real environmental data and to acquire them. Environmental data retrieval technology based on Fuzzy criteria is one of the important technologies for developing Environmental Scenario Generator. As a result of this study, a fuzzy retrieval algorithm composed of four main parameters(RV, MF, FRA, and MRV) was presented. This study suggests that the RV can be used as 14 m/s for wind speed and 80 mm/d for precipitation to search the date of storm accompanied by high wind. The MF, the FRA, and MRV can be used sigmoid, 0.2, and 1 respectively. The algorithm proposed in this study is expected to be very useful for searching the date on which weather phenomena necessary for simulation occurred.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.10
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• pp.3438-3457
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• 2022

As location-based services (LBS) are widely used in vehicular ad-hoc networks (VANETs), location privacy has become an utmost concern. Spatial cloaking is a popular location privacy protection approach, which uses a cloaking area containing k-1 collaborative vehicles (CVs) to replace the real location of the requested vehicle (RV). However, all CVs are assumed as honest in k-anonymity, and thus giving opportunities for dishonest CVs to submit false location information during the cloaking area construction. Attackers could exploit dishonest CVs' false location information to speculate the real location of RV. To suppress this threat, an edge-assisted Trusted Collaborative Anonymity construction scheme called TCA is proposed with trust mechanism. From the design idea of trusted observations within variable radius r, the trust value is not only utilized to select honest CVs to construct a cloaking area by restricting r's search range but also used to verify false location information from dishonest CVs. In order to obtain the variable radius r of searching CVs, a multiple linear regression model is established based on the privacy level and service quality of RV. By using the above approaches, the trust relationship among vehicles can be predicted, and the most suitable CVs can be selected according to RV's preference, so as to construct the trusted cloaking area. Moreover, to deal with the massive trust value calculation brought by large quantities of LBS requests, edge computing is employed during the trust evaluation. The performance analysis indicates that the malicious response of TCA is only 22% of the collaborative anonymity construction scheme without trust mechanism, and the location privacy leakage is about 32% of the traditional Enhanced Location Privacy Preserving (ELPP) scheme.

• Journal of The Korean Astronomical Society
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• v.56 no.2
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• pp.195-199
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• 2023

This paper is written as a follow-up observations to reinterpret the radial velocity (RV) of HD 36384, where the existence of planetary systems is known to be ambiguous. In giants, it is, in general, difficult to distinguish the signals of planetary companions from those of stellar activities. Thus, known exoplanetary giant hosts are relatively rare. We, for many years, have obtained RV data in evolved stars using the high-resolution, fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) at the Bohyunsan Optical Astronomy Observatory (BOAO). Here, we report the results of RV variations in the M giant HD 36384. We have found two significant periods of 586 d and 490 d. Considering the orbital stability, it is impossible to have two planets at so close orbits. To determine the nature of the RV variability variations, we analyze the HIPPARCOS photometric data, some indicators of stellar activities, and line profiles. A significant period of 580 d was revealed in the HIPPARCOS photometry. H_α EW variations also show a meaningful period of 582 d. Thus, the period of 586 d may be closely related to the rotational modulations and/or stellar pulsations. On the other hand, the other significant period of 490 d is interpreted as the result of the orbiting companion. Our orbital fit suggests that the companion was a planetary mass of 6.6 M_J and is located at 1.3 AU from the host.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.2
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• pp.361-370
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• 2024

In this paper, a method was studied for applying a series resonant type fault current limiter that can be manufactured at low cost to the smart grid distribution system. First, the impact of the harmonic components of the short-circuit fault current injected into the series resonance circuit of the fault current limiter on the peak value of the transient response was analyzed, and a methodology for determining the steady-state response was studied using percent impedance-based fault current computation method. Next, the effectiveness of the method was verified by applying it to a test distribution line. The test distribution system using the designed current limiter was modeled using EMTP_RV, and a three-phase short-circuit fault was simulated. In the fault simulation results, it was confirmed that the steady-state response of the fault current accurately followed the design target value after applying the fault current limiter. In addition, by comparing the fault current waveform before and after applying the fault current limiter, it was confirmed that the fault current was greatly suppressed, confirming the effect of applying the series resonance type current limiter to the distribution system.

• Pediatric Infection and Vaccine
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• v.21 no.3
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• pp.181-190
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• 2014

Purpose: This study was performed to investigate the epidemiological trend of rotavirus acute gastroenteritis (RV-AGE) in children. Methods: A retrospective review was performed in patients (1 month to 18 years of age) with acute gastroenteritis at KEPCO Medical Center from September 2004 to August 2013. Comparative analyses were performed based on periods: pre-vaccine (2004-2006) and post-vaccine (2008-2012) in all patients; 2004-2006 (period A), 2007-2009 (period B) and 2010-2012 (period C) in patients under 5 years of age. Results: Proportion of RV-AGE decreased from 25.0% (337/1,346) in pre-vaccine period to 20.8% (459/2,210) in post-vaccine period (rate ratio (RR), 0.83 [95% CI, 0.73-0.93]; P=0.0029). The median age of patients with RV-AGE in post-vaccine period (2.6 years) was significantly (P<0.0001) higher than that in pre-vaccine period (1.6 years). In patients hospitalized with AGE, proportion of RV-AGE was significantly reduced in patients 6 to 23 months old (RR, 0.62 [95% CI, 0.51-0.75]; P<0.0001). Significant decline in proportion of RV-AGE was observed in patients under 5 years of age: period A, 26.9% (308/1,144); period B, 22.7% (295/1,299); period C, 20.6% (186/902) (P =0.0007). After the introduction of rotavirus vaccine, a significant decreasing trend of RV-AGE proportion was observed in patients 6 to 11 months old (P =0.0018) and 12 to 23 months old (P =0.0152). Conclusion: Decrease in RV-AGE proportion and increase in age of patients with RV-AGE were observed after the introduction of rotavirus vaccine in this single center study. Continued and systematic surveillance is needed to assess the impact of rotavirus vaccine.

• Clinical and Experimental Pediatrics
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• v.51 no.8
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• pp.834-841
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• 2008

Purpose : This study was perfomed to analyze in detail the viral etiology of acute lower respiratory tract infections (ALRI) in Cheunan, Korea by multiplex RT-PCR, including human rhinovirus (hRV) and newly identified viruses such as human metapneumovirus (hMPV) and human coronavirus (HCoV-OC43, HCoV-229E/NL63). Method : Nasopharyngeal aspirates (NPA) were collected from 863 hospitalized children with ALRI on the first day of admission at Soonchunhyang University Cheonan Hospital and analyzed by multiplex RT-PCR from December 2005 to November 2006. Results : Viral agents were detected from 474 subjects (54.9%). The identified viral pathogens were hRV 9.2%, hMPV 6.8%, HCoV-229E/NL63 1.4%, and HCoV-OC43 2.1%. Coinfections with ${\geq}2$ viruses were observed in 108 patients (22.8%). The major period of viral ALRI was the first year of life. Clinical diagnoses of viral ALRI were pneumonia (59.5%), bronchiolitis (24.7%), tracheobronchitis (11.4%), and croup (4%). The most common causes of bronchiolitis was respiratory syncytial virus B (RSV B), whereas hMPV, hRV, HCoV-229E/NL63, and HCoV-OC43 were commonly found in patients with pneumonia. The number of hMPV infections peaked between March and May 2006. HCoV-OC43 was prevalent from November to February 2006, whereas HCoV-229E and hRV were detected throughout the year. Conclusion : Although the study was confined to one year, hMPV was not detected during winter and peaked between March and April, which was not consistent with previous studies'. This present study indicates that HCoV is a less common respiratory pathogen in cases of ALRI in Korean children

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.90-95
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• 2004

The probabilistic fracture analysis is used to determine the effects of uncertainties involved in material properties, location and size of flaws, etc, which can not be addressed using a deterministic approach. In this paper the probabilistic fracture analysis is applied for evaluating the RV(Reactor Vessel) under PTS(Pressurised Thermal Shock). A semi-elliptical axial crack is assumed in the inside surface of RV. The selected random parameters are initial crack depth, neutron fluence, chemical composition of material (copper, nickel and phosphorous) and $RT_{NDT}$. The deterministically calculated $K_I$ and crack tip temperature are used for the probabilistic calculation. Using Monte Carlo simulation, the crack initiation probability for fixed flaw and PNNL(Pacific Northwest National Laboratory) flaw distribution is calculated. As the results show initiation probability of fixed flaw is much higher than that of PNNL distribution, the postulated crack sizes of 1/10t in this paper and 1/4t of ASME are evaluated to be very conservative.

• Journal of Chest Surgery
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• v.20 no.1
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• pp.202-208
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• 1987

Congenital coronary artery fistula is a rare condition, and with widespread use of cardiac catheterization, angiography and selective coronary arteriography are being recognized with increasing frequency. Fistula originating from the right coronary artery are more common then those from the left coronary artery. The fistula empties into the right side of the heart in 90% of the cases with the right ventricle being the most common recipient chamber followed by the right atrium and the pulmonary artery. Recently we experienced two cases of congenital coronary artery fistula which originated from the left coronary artery each other. The first case was 17 moth-old-male, who have had the symptoms of frequent URI, dyspnea and continuous murmur in physical examination. The fistulous communication was noted between the left circumflex coronary artery and the right ventricle with aneurysmal dilation of RV wall. The proximal opening of the fistulous tract was directly close with partial aneurysmorrhaphy of RV wall. Also the termination site of fistulous tract in RV chamber was closed. The second case was 35-year-old female, who have had the symptom of exertional dyspnea and continuous murmur in physical examination. The tortuous and dilated fistulous tract was noted between the left anterior descending coronary artery and the pulmonary artery. The proximal opening of the fistula was ligated near the left anterior descending coronary artery with preservation of normal continuity of coronary artery. And the dilated tortuous vessel was excised. Also the terminal site in pulmonary artery was directly closed just above the pulmonic valve. Postoperative hospital courses of two patients were uneventful without any specific complications and discharged without problems.

• Journal of Species Research
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• v.5 no.3
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• pp.547-550
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• 2016

Hemicycliophora litoralis is newly collected from Korea. Korean population is well matched and within a range of original description and additional record from Solomon island in de Man's of L, b, c, V, R, Rex, Ran, Roes, RV (ant), annule, excretory pore, stylet length, and tail length. Differences are observed in RV and RVan. RV and RVan of original description was 55 (48-69) and 14 (10-19) but Korean population is 68 (61-76) and 22 (19-24), respectively. H. litoralis described from Solomon island has RVan of 19.6 (17-23) and is similar to Korean population. H. litoralis from Solomon island has slight higher Rst value of 39 (35-59) compared to Korean population of 33.5 (29-38). The measurements of MB (%), s, G1, G2 values are newly given.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.77.1-77.1
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• 2012

We present high-resolution radial velocity measurements of K2 giant ${\varepsilon}$ CrB from February 2005 to January 2012 using the fiber-fed Bohyunsan Observatory Echelle Spectrograph at Bohyunsan Optical Astronomy Observatory. We find that the RV measurements for ${\varepsilon}$ CrB exhibit a periodic variation of 418 days with a semi-amplitude of 129 m/s. There is no correlation with RV measurements and inhomogeneous surface features by examining chromospheric activity indicator (Ca II H region), the Hipparcos photometry, and bisector velocity span. Thus, Keplerian motion is the most likely explanation, which suggests that the RV variations arise from an orbital motion. Assuming a possible stellar mass of 1.7 $M_{\odot}$, for ${\varepsilon}$ CrB, we obtain a minimum mass for the planetary companion of 6.7 $M_{Jup}$ with an orbital semi-major axis of 1.3 AU, and an eccentricity of 0.11. We support that more massive stars harbor more massive planetary companions in giant hosting planetary companions (Dollinger et al. 2009), as well as, we discuss the frequency of detected planetary companions with the metallicity distribution in giant (Pasquini et al. 2007; Quirrenbach et al. 2011).