• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2002년도 ITC-CSCC -3
• /
• pp.1590-1593
• /
• 2002

We propose a dynamic location management scheme and named it Virtual Dynamic Location Area(VDLA) scheme. It allocates LA on the basis of terminal mobility, VDLA consists of two phases: VLA allocation and final LA selection phases. In the first phase it allocates primary and secondary VLAs to the terminal. In the second phase the terminal selects one of them using LA selection criterion. Cost analysis of the proposed scheme is peformed and its location management cost is compared with those of FLA and DBLA.

• 천문학회보
• /
• 제37권2호
• /
• pp.87.2-87.2
• /
• 2012

The HI absorption against bright continuum source provides a unique opportunity to measure spin temperature of the neutral hydrogen gas. We find three cases among the sample of the VIVA (VLA Imaging of Virgo galaxies in Atomic gas) study with self absorption of strong central continuum by galactic HI gas. Using the HI flux ratio of emission and absorption, we constrain the spin temperature of the neutral hydrogen gas on their disk. The HI absorption is marginally resolved in these galaxies, which also allows us to probe the kinematics of the absorbing gas. All three galaxies are severely stripped in HI due to the intra cluster medium (ICM). We discuss the influence of environmental processes on the temperature and kinematics of HI in these galaxies.

• 천문학회보
• /
• 제36권1호
• /
• pp.51.2-51.2
• /
• 2011

The Spitzer Public Legacy Survey of the UKIDSS Ultra Deep Survey (SpUDS) has been carried out with four IRAC bands and one MIPS band (24um). SpUDS surveys 1 square degree of the UDS field, that has been covered by one of the deepest near IR surveys and by various multiwavelength observations from X-ray to radio (XMM, GALEX, Subaru, SCUBA, VLA). We present a summary of the photometric data including number counts derived at 3.6-24 microns. In conjunction with extensive multiwavelengh data, we are able to show the multiwavelenght color distribution of MIR sources, and how different SED types contribute to the number counts.

• 천문학회지
• /
• 제29권spc1호
• /
• pp.77-78
• /
• 1996

We perfom a large project for complex study of Blue Compact Galaxies (BCGs) with strong star formation, which includes optical spectroscopy, BVR CCD photometry and HI 21 cm radio survey. The most interesting galaxies are studied also with HST and VLA. In the frame of this project we began the study of H$\alpha$ morphology of BCGs with 6-m telescope. We present and discuss here the results for the first 6 galaxies. We found the noticeable variety of forms for H$\alpha$ morphology comparing to broad band images: from very compact HII region in very center of stellar body (Mark 996, possible dwarf post-merger, old galaxy experiencing strong star formation burst), to very extended gas emission encompassing the whole area traced by stars (SBS 0335-052, the most probable young galaxy in formation).

• 천문학회보
• /
• 제45권1호
• /
• pp.65.2-65.2
• /
• 2020

We present NIR spectroscopic data of young radio quasars obtained from Flamingos-2 (F2) at Gemini-South. The targets are originally selected from Wide-Field Infrared Survey Explorer survey in combination with radio survey data, such as FIRST and NVSS. Our goal is to find observational evidence of jet-driven outflows, which is expected to be present in young luminous quasars from the theoretical studies. While 16 targets were observed with F2, narrow emission lines ([O III] or Hα) were detected in 7 targets. FWHM of the emission lines (up to 2500 km/s) were remarkably broad compared to ordinary quasars, revealing the presence of strong outflows. The black hole mass estimated from Eddington limit ranges from ~108 to 109 solar mass, indicating that the target quasars are likely to be progenitors of massive galaxies. Finally, we present the comparisons between the outflow velocity and the physical properties of radio jets derived from the VLA radio imaging data, in order to investigate the physical connection between the ionized outflows and radio jets.

• 천문학회보
• /
• 제45권1호
• /
• pp.35.2-35.2
• /
• 2020

Submillimeter galaxies (SMGs) have played an important role in the understanding of galaxy evolution and cosmic star formation history at high redshift because they are known as being located at z ~ 2 and harbor a vigorous star formation. Therefore studying properties of SMGs can lead us to understand evolution of massive and actively star forming galaxies and distribution of cosmic star formation density. Recently we detected 548 SMGs near North Ecliptic Pole with JCMT/SCUBA-2 from the JCMT large program covering about 2 deg2 so far. To derive their physical parameters, we compiled a multi-wavelength photometry ranging from optical (0.3 ㎛) to submillimeter (850 ㎛) by cross-identifying counterparts at different wavelengths. In order to find counterparts, we used either VLA-1.4 GHz image and/or Spitzer/IRAC 3.6 ㎛, 4.5 ㎛ image. The number of SMGs with relatively robust counterparts is 349. In this talk, we present photometric redshifts, stellar mass, star formation rates, total infrared luminosity, and AGN fraction of these 349 SMGs derived through SED fitting analysis.

• 천문학회보
• /
• 제46권2호
• /
• pp.39.3-40
• /
• 2021

The Faraday rotation measure (RM) of extragalactic radio sources is one of tools that can explore the magnetic field in the cosmic web. We have investigated the statistical properties of the RM using the data of simulations for the large-scale structure formation of the universe. Various modelings for the cosmic magnetic field including the redshift dependence, and the intrinsic RM of radio sources have been considered. We here present the structure functions (SFs) of simulated RMs for small angular separations, and compare the SFs with observations, specifically those from the NRAO VLA Sky Survey (NVSS) and LOFAR Two-Metre Sky Survey (LoTSS). We then discuss the implications of our work.

• 천문학회보
• /
• 제46권2호
• /
• pp.69.1-69.1
• /
• 2021

We present preliminary results of the VLA archival HI data of local AGN hosts. The sample consists of the galaxies selected from the Swift-BAT hard X-ray survey. The main goal is to probe the gas environment of the sample in order to verify the role of gas accretion as one of the major AGN triggering mechanisms. HI, as a mostly diffuse and extended gas component in many galaxies, is a sensitive tracer to explore the impact of the surroundings on galaxies. In this work, we therefore probe the HI imaging data of a subsample of BAT-BASS AGN hosts, starting with the cases for which relatively high HI fluxes have been reported from the past single-dish observations. Based on their resolved HI properties, we will discuss the possibility of gas accretion and its role in powering AGNs in these examples.

• Tuberculosis and Respiratory Diseases
• /
• 제42권6호
• /
• pp.823-830
• /
• 1995

연구배경: 결핵감염시 세포매개성 면역반응이 관여하여 말초혈액내 조력 T 세포가 감소하는 것으로 알려저왔다. 그러나 말초혈액내 표지물질을 가진 세포의 수적 감소가 세포매개성 면연반응의 저하라고 할 수있지 여부가 앞으로 해결해야 될 문제인 것으로 지적되고 있다. 이에 저자들은 폐결핵 환자들의 말초혈액에서 활성화된, 또는 활성화 되고 있은 세포의 수적변화를 관찰하기 위하여 본 연구를 시행하였다. 방법: 객담 결핵균 양성인 폐결핵 환자 22명을 대상으로 말초혈액에서 IL-2R, VLA-1, TLiSAI의 활성화 표지에 대한 단세포군 항체를 면역조직 화학법으로 측정하였다. 결과: 1) 폐결핵 환자의 말포혈액에서 $T_1$(+) 세포 및 그 아형들의 단위 부피당 절대수는 $T_4$(+) 세포는 유의하게 감소하였고 $T_8$(+) 세포는 증가하였다(p<0.05). 2) 폐결핵 환자에서 전체 T임파구의 비율은 감소되어 있으며 $T_4$(+) 세포, $T_8$(+) 세포비율은 각각 유의하게 감소, 증가하였다. 또한 $T_4(+)/T_8(+)$ 비율도 유의한 감소가 있었다(p<0.05). 3) 폐결핵 환자에서 activated T cell의 단위 부피당 절대수는 대조군에 비해 모두 유의한 증가를 보였다(p<0.05). 4) 폐결핵 환자에서 activated T cell 비율은, IL-2R, VLA-1, TLiSAI, 각각 6.45+1.56%, 7.64+1.34%, 10.45+1.16%로 모두 대조군에 비해 모두 유의한 증가를 보이며 특히 TLiSAI 항체가 가장 많이 관찰 되었다. 결론: 폐결핵 감염시 말초혈액 임파구의 일부만이 활성화되어 세포매개성 면역반응에 참여하는 것으로 사료된다.

• 한국음향학회지
• /
• 제23권1호
• /
• pp.8-16
• /
• 2004

천해환경에서 저주파 광대역신호와 수직선배열을 이용하여, 퇴적층의 지음향인자(층두께, 종파속도, 종파감쇠계수, 밀도)를 역추정하였다. 역산방법은 모델 기반의 역산으로 유전알고리즘 (Genetic Algorithm)을 이용한 일관적 광대역 정합장처리(Coherent Broadband Matched Field Processing)기법을 사용하였다. 저주파 광대역음원으로 사용된 상업용 전구의 내폭신 호는 짧은 시간동안 많은 변화를 포함하는 천이신호이기 때문에, 분석시 시간과 주파수에 따른 창함수의 조절이 요구되는데, 주기신호분석에 주로 사용되는 퓨리에 기반의 분석방법은 이러한 점에서 많은 어려움이 있다. 본 논문에서는 해양도파관에서 근거리 음파전달 시 계측된 시계열신호로부터 다중경로성분을 구분하고 추출하기 위하여 시간-주파수영역에서 창함수의 크기조절이 가능한 웨이블릿 변환을 통한 신호 분석을 수행하였고, 분석된 실측음장과 계산된 복제음장의 연속웨이블릿 계수를 상호상관 시킴으로써 비용함수를 정의하였다. 비용함수의 전역최고점을 찾는 최적화 과정을 통하여 각 퇴적층의 지음향인자들을 역추정하였다. 특히 역산인자의 민감도에 따른 퇴적층별, 인자별, 분리연산을 수행함으로써 최적화과정에서 참값으로의 수렴효율을 높였다. 역산의 결과 실험해역 퇴적물 상층부에는 두께 44.43m, 음속 1549 m/s의 모래-실트-점토질(sand-silt-clay)층이 존재하고, 그 하부에는 12.28m 음속 1993 m/s의 거친모래질(Coarse sand)층의 존재를 추정해 내었다. 또한 역산 결과를 시추자료 및 탄성파 자료와 비교함으로써 본 논문에서 제안한 역산 방법의 유효성을 확인하였다.