• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.80.2-80.2
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• 2014

We present the results of high resolution (R>35,000) optical spectroscopic monitoring observations of a new FU Orionis-like young stellar object, HBC 722. We observed HBC 722 with the Bohyunsan Optical Echelle Spectrograph (BOES) and Hobby-Eberly Telescope (HET) since November 26, 2010. HBC 722 is the FU Orionis-like object best characterized for the pre-outburst phase, and it provides the first opportunity to profile the burst phase of accretion across all wavelengths. We detected a number of lines such as $H{\alpha}$, $H{\beta}$, Fe II ${\lambda}$ 5018, Mg I ${\lambda}$ 5183, Na I D doublets, and metallic photospheric lines. In this work, we focus on the time variations of those spectral lines to understand the accretion process of HBC 722.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.89.1-89.1
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• 2017

In this poster, we present standard calibration processes and results for photometry of $H-{\alpha}$ filter using broadband filters. We took data from a night in stable weather condition. And we derived parameters for band pass calibration including color terms. The corrected photometry results from broadband filters like V and R filters showed high correlation enough to replace instrumental $H-{\alpha}$ magnitude. We plan to extend these standardizing processes to another narrowband filters and flux calibration of narrowband filters from photometry of PNe.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.49.2-49.2
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• 2018

Flux calibration for narrow band photometric data gives us an opportunity to get a line flux of extended targets. We developed flux calibration processes for narrow band photometry using broad band filters as a continuum indicator. We derived parameters for color correction and zero point correction including color terms. Applying our method, we successfully subtracted continuum emissions and calibrated the emission lines from an FU Ori type object, V960 Mon.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.88.1-88.1
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• 2014

국립고흥청소년우주체험센터는 2014년 11월에 1,040mm의 반사망원경을 도입할 예정이다. 그 사전 준비로 천체관측소 10m돔에 150mm 굴절망원경과 1K CCD카메라를 설치하고, 이를 통합 제어할 원격관측시스템을 구축하였다. 원격으로 제어가 가능한 이 시스템은, 망원경 구동부, CCD, 돔을 제어할 수 있는 소프트웨어, 각 기기를 원격에서 조정 작동할 수 있는 장비, 기상과 하늘의 실시간 상황 및 망원경의 상태를 확인 할 수 있는 원격 모니터링 카메라 등으로 구성되어 있다. 구축 이후 M67 산개성단과 SA98 표준성 영역을 원격으로 관측하였다. 이를 통해, 관측시에 발생할 수 있는 문제점과 장애요인을 분석하여 보완 개선하였고, 시범관측으로 확보한 자료를 활용하여 관측환경을 정량화하는 중이다. 최우선 과제는 센터가 위치한 내나로도 지역의 시상정보를 검증하고 축적하는 일이다. 센터는 천체관측소에 시상 관측기 설치하여 자료를 축적하고 있다. 이 정보의 신뢰성을 확보하기 위해 150mm 굴절망원경으로 얻어진 시상정보와 비교 검증하고자 한다. 또한 이 과정에서 센터 천체관측소에 구축된 망원경으로 관측 가능한 한계등급을 얻을 수 있었고, 표준계 변환작업을 통해 1차와 2차 소광계수를 구해 보았다. 추가적으로 관측 가능한 일수를 지속적으로 기록하여, 계절별, 월별 관측 가능일 수를 조사할 예정이다.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.51.1-51.1
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• 2018

Based on the DOAO/eShels observations, we have derived radial velocity curves of the three Algol-type spectroscopic binary systems : Algol, ${\beta}$ Aur, and ${\varepsilon}$ Per. The radial velocity amplitudes of the primary and the secondary (K1 and K2) were consistent within a few % of the values from the previous studies. Mass ratios between the two stars that constitutes each system ranges ~1 to ~10. In addition to the orbital elements derived, we discuss about the spectroscopic ability of the DOAO/eShels instrument.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.60.2-60.2
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• 2019

Based on our experience on exoplanet transit observation, we propose the exoplanet science cases with Small Telescope Network. One is the follow-up observation for validation of exoplanet candidates. TESS(Transiting Exoplanet Survey Satellite) is pouring out exoplanet candidates in bright stars(V<15) on all the sky. Since Small Telescope Network will consist of 0.5-1m telescopes, we will expect to produce promising outcomes from the follow-up observation of bright candidates. Next is the transit time observation. By spectroscopy of space and large telescopes during transit event, it can be possible to find the bio signatures in exoplanet atmosphere. So, in terms of cost, it is critical to determine the exact time of transit event. In addition, detecting the variation of transit time can reveal another exoplanet and exomoon in the system. In order to determine the transit time and its variation, the accumulation of transit event data is more important than the quality of photometric data. We expect that it can be a challenging project of Small Telescope Network.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.48.3-48.3
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• 2021

SomangNet is a project that started in 2020 with a network of ten 0.4 to 1.0 m telescopes owned by Korean institutes. By coordinating observations with multiple facilities around the world, we hope to maximize the usefulness of small telescopes which are still competitive for carrying out time-domain astronomy projects. In this talk, we will give an overview of the project, outlining SomangNet facilities, its organization, and current science projects. We hope to open SomangNet for common use in 2021B, and we will present our plan regarding the use of SomangNet.

• International Journal of Computer Science & Network Security
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• v.24 no.5
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• pp.205-211
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• 2024

The increasing number of botnet attacks incorporating new evasion techniques making it infeasible to completely secure complex computer network system. The botnet infections are likely to be happen, the timely detection and response to these infections helps to stop attackers before any damage is done. The current practice in traditional IP networks require manual intervention to response to any detected malicious infection. This manual response process is more probable to delay and increase the risk of damage. To automate this manual process, this paper proposes to automatically select relevant countermeasures for detected botnet infection. The propose approach uses the concept of flow trace to detect botnet behavior patterns from current and historical network activity. The approach uses the multiclass machine learning based approach to detect and classify the botnet activity into IRC, HTTP, and P2P botnet. This classification helps to calculate the risk score of the detected botnet infection. The relevant countermeasures selected from available pool based on risk score of detected infection.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.2
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• pp.67-80
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• 2020

This study has been conducted at a time when Korean government continues to extend support for youth startups as part of its policy to create jobs and the focus moves from career and employment to youth startups with a growing interest in the field of youth startups. Against this background, this study aims to identify difficulty factors of youth startups in areas besides the Seoul Metropolitan Area, seek ways to overcome difficulty factors, and propose policy implications. To this end, this study set five criteria and 25 sub-criteria to evaluate the difficulties of youth startups by reviewing previous studies and conducting literature review, and performing brainstorming method. The empirical analysis of the evaluation criteria was performed, using the analytic hierarchy process (AHP) method, on youths aged 19 to 39 in Gunsan area. The analysis results showed that the largest difficulty factors facing local youths include business model establishment, business administration and management, and startup funding in the criteria. As for sub-criteria, the largest difficulty factors are market information acquisition, technology commercialization, project feasibility, technology development, and new market pioneering in descending order. Local youths have much difficulty about the process of turning a business item into a product and commercializing it. According to a comparative analysis by gender, men were a relatively high difficulty in commercializing business models than women. men were a relatively high difficulty in commercializing business models than women. On the other hand, women were higher than men in all factors (management management, entrepreneurship, improvement of entrepreneurship system, and improvement of entrepreneurship awareness) except for factors affecting business model. In addition, the factors of entrepreneurship were found to be relatively different among young people (college students, prospective entrepreneurs, entrepreneurs). In conclusion, it was suggested that in order to revitalize youth entrepreneurship in the region, it is necessary to actively resolve the difficulties of business model commercialization rather than entrepreneurship funds. In addition, it is necessary to strategically support customized entrepreneurship support and situational administrative services because gender and hierarchical difficulties are different than general solutions. This study presented practical priorities and derivation methods for the entrepreneurship difficulties faced by local youth, and suggested measures and improvements for vitalizing local youth entrepreneurship in the future.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.31 no.1
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• pp.33-40
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• 2020

Objectives: There is an increasing number of North Korean adolescents in South Korea. These adolescents need clinical attention as they experience a high risk of suicidal behavior because of the childhood adversity and acculturative challenges that they face before and after arriving in South Korea. This study assessed the risk of suicide attempts among North Korean adolescents compared to South Korean adolescents, and investigated the contributing factors for each group. Methods: We used data from the Korean Youth Risk Behavior Web-Based Survey (KYRBS) spanning 2011 to 2018, in which 404 adolescents had a father and/or mother who was a North Korean native. Data on 1,212 propensity-matched South Korean adolescents were extracted from the 2011 to 2018 KYRBS. Prevalence was calculated and compared by group. Separate odds ratios were calculated by group. Results: The North Korean group had a significantly higher suicide attempt rate [unadjusted odds ratio (OR)=8.27; adjusted OR=8.45]. Multivariate analysis indicated that having a low or high socioeconomic status and depressive symptoms were significantly associated with suicide attempts in North Korean adolescents, while being female, having a high socioeconomic status, alcohol use, and depressive symptoms were significantly related to suicide attempts in South Korean adolescents. Conclusion: The results found similarities and differences in the factors associated with the likelihood of suicide attempts in the two groups. From these results, different approaches are needed when planning interventions for each group.