• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.74.4-75
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• 2015

We investigate the narrow emission-line ratios of 64 radio-loud (log $L_{1.4GHz}$ > 40) AGNs available in the SDSS archive, in order to examine whether there is a systematic difference in the accretion disk condition of radio-loud AGNs compared to radio-quiet AGNs and compact young radio-loud AGNs. The fluxes of narrow-emission lines, [O II], [Ne III], [O III], [O I], [Ar III], are measured for diagnostics. Based on the [O I]/[O III] and [Ar III]/[O III] ratios with photoionization models, we constrain the states of the accretion disk. We will present the results of the emission-line diagnostics.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.419-420
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• 1996

The VLBI Space Observatory Program (VSOP) is a worldwide project of one radio telescope in space with many ground radio telescopes. The concerted space VLBI network enables us to reveal high resolution and high quality images of radio sources. The space radio telescope is anticipated to be launched in January/February 1997, and collaborative observations have been coordinated. The basic parameters of the system and present status are given.

• Publications of The Korean Astronomical Society
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• v.20 no.1 s.24
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• pp.73-83
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• 2005

On-The-Fly (OTF) observation method is developed for the efficient use of 6 M radio telescope at Seoul Radio Astronomy Observatory (SRAO). This technique, in which data and information of antenna position are recorded synchronously while driving a telescope regularly and rapidly across a field, provides more efficient use of telescope time and better calibration of the acquired data than the traditional point-to-point observation method does. For the realization of the method, we (1) added RT-Linux modules to the existing operating system, (2) replaced digital voltmeter with voltage-to-frequency converter, and (3) modified many SRAO observation programs. By observing Moon and G78.2+2.7 using this method and comparing them with previous observations, we verify the successful operation and efficiency of the OTF observation mode.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.453-455
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• 2015

In this paper we introduce the Plasma Physics of Active Galactic Nuclei project, which is an ongoing experiment with Korean VLBI Network (KVN) and KVN and VERA Array (KaVA) to study multi-frequency polarimetric properties on parsec scales of active galaxies. The goal of the project is to improve our understanding of fundamental jet physics, especially evolution of the relativistic outflow coupled with the large-scale magnetic field. We selected six radio-loud AGN as our targets. So far we (i) detected resolved emissions regions at 86 and 129 GHz on VLBI scales, (ii) constructed 2D spectral index maps of the outflows, and (iii) found polarizations at 22 and 43 GHz for a few targets. Here we present spectral index distributions of 3C 120 between 22 and 43 GHz and a linear polarization map of BL Lac at 43 GHz obtained with KVN.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06a
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• pp.101-105
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• 1996

근래에 기존의 텔레비젼이나 라디오 방송에서 영상이나 음성의 방송 외에, 할당된 주파수를 최대한 효율적으로 사용하기 위한 부가방송의 개발이 활발히 이루어지고 있다. KBS에서는 오래 전부터 데이터 방송분야의 개발에 힘써왔으며 라디오에서는 RDS를 이용한 데이터 방송이 실용화 단계에 들어가고 있다. 1995년 하반기부터 KBS 제1라디오(표준FM)를 통하여 전국적으로 RDS 시험 방송을 하고 있으며, 또한 1997년에 문자정보 서비스를 위해 한국 실정에 맞는 새로운 RDS 한글 문자정보 규격을 만들어 서비스를 할 예정이다.

• Journal of Astronomy and Space Sciences
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• v.24 no.4
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• pp.297-308
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• 2007

The AOPOD (Atmosphere Occultation and Precision Orbit Determination) system, the secondary payload of KOMPSAT (KOrea Multi-Purpose SATellite)-5 scheduled to be launched in 2010, shall provide GPS radio occultation data. In this paper, we simulated the GPS radio occultation characteristic of KOMPSAT-5 and retrieved electron density profiles using KROPS (KASI Radio Occultation Processing Software). The electron density retrieved from CHAMP (CHAllenging Minisatellite Payload) GPS radio occultation data on June 20, 2004 was compared with IRI (International Reference Ionosphere) - 2001, PLP (Planar Langmuir Probe), and ionosonde measurements. When the result was compared with ionosonde measurements, the discrepancies were 5 km on the $F_2$ peak height ($hmF_2$) and $3{\times}10^{10}el/m^3$ on the electron density of the $F_2$ peak height ($NmF_2$). By comparing with the Laugmuir Probe measurements of CHAMP satellite (PLP), both agrees with $1.6{\times}10^{11}el/m^3$ at the height of 365.6 km.

• Journal of Broadcast Engineering
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• v.22 no.4
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• pp.462-472
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• 2017

As network technology evolves fast, media contents of particular countries are being consumed in not only the countries but also other countries around the world. Like this, in case that a particular media content is consumed in various country, method for inserting or replacing in-program ads which are appropriate to national/regional environment seems needed. For this, this paper proposes measures to insert in-program ads on hybrid broadcast environment based on MMT, next generation broadcasting standard. This paper analyzed structure of MMT, designed a system for verifying the proposed system and showed the result of experiment.

• Korean journal of communication and information
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• v.16
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• pp.36-70
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• 2001

The purpose of this study is to investigate women's radio talk program and evaluate its possibilities and limitation from the point of feminist perspective. The theoretical framework is based on feminist studies and text analysis of talk show. Existing studies regarding talk show are mainly focused on television. But radio talk show is one of general entertainment and it's influences on minorities are still significant. is the most representative women's radio talk program in Korea. It has been broadcasted over 10 years and very popular among Korean housewives. The audience of this program call themselves schoolfellow, and call the program 'school of women'. The media text of is mainly consisted of letters from women audiences, and they are selected by producers. So the text is made by both audiences and producers. The unique combination of this process produces complicated discourses which contain women's experiences in letters and station's considerations through safekeeping. The problems investigated in this study are as follows: First, What discourses are produced in this program? Second, Alternative possibilities can be seen in this program in feminist perspectives? Text analysis of 1week(2000.9.18-9.24) and interview with producers are accomplished to this purposes. In the text analysis, subject matters, inscribed women's position, values of the letters are revealed. Most of the subject matters are family affairs. Some are socially oriented but family and home are the predominant category of women's letters. And the position of women subject is defined in the domestic network. They are nameless but the mother, wife, daughter, daughter-in-law of other people. In value, family-oriented value and small happiness in everyday life are generally appeared. But these values are essentially coincide with the values of status quo. The answers of the conflict are not public but individualized. And acception the status quo is presented as the wisest decision, But ` has many implications in relation to women's sharing of their experience, and construction of imagined community in media. Women continuously interact each other revealing and discussing their experiences and sometimes their social practices are stirred through this media sphere. So we see the 'emotional union' among women are formed through radio. The limitation of this program is very apparent: it's patriarchic values, acception of status quo, and individualization of the women's problems. But in the same time we can read coexisting it's latent possibilities: the possibilities of women's public sphere. But it is completely alternative women's sphere in feminist perspectives. It renders women opportunities to participate public media and share with other women, and collaborate with their problem.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.314-317
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• 2003

In this paper, a measurement and analysis program is developed, that can be utilized to measure and analyze radio propagation characteristics. This program is able to control the measurement instruments including spectrum analyzer through a GPIB interface, and analyze the measured data to yield mean excess delay and RMS delay spread. The measured path loss can be compared with theoretical path loss in free space or inside tunnels. The measured and analyzed results can also be presented in the forms of graphs. As those tasks can be conducted on the measurement spot, this program is very helpful for performing and verifying measurements.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.73.3-73.3
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• 2019

A Korean VLBI Network $1^{st}$ generation key science program, the Interferometric Monitoring of Gamma-ray Bright AGNs (iMOGABA) program has revealed various natures of gamma-ray flares in active galactic nuclei (AGNs). Here in this presentation, we would like to introduce a new candidate of KVN $2^{nd}$ generation key science program, so called, the AiMOGABA (Astrometric iMOGABA), aiming at studying a wondering radio core effect of relativistic jets from AGNs with high resolution VLBI astrometric monitoring of high-energy bursting AGNs with KVN as well as a Australian millimeter radio telescope MOPRA. The introduction will include the current scientific highlights of the iMOGABA, and the overview of the AiMOGABA.