• Title/Summary/Keyword: Local spectrum

Search Result 334, Processing Time 0.026 seconds

Far Ultraviolet Observations of the Spica Nebula and the Interaction Zone

  • Choi, Yeon-Ju;Park, Jae-Woo;Lim, Tae-Ho;Min, Kyoung-Wook;Seon, Kwang-Il;Jo, Young-Soo
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.37 no.2
    • /
    • pp.99.1-99.1
    • /
    • 2012
  • We report the results of our analysis of far ultraviolet (FUV) observations made for the broad region around the ${\alpha}$ Vir (Spica) including the interaction zone of the Loop I and the Local Bubble. We employed the datasets of the GALEX and the FIMS, which made observations at similar FUV wavelengths. First, we noted that the GALEX image was enhanced in the southern region where the interaction zone exists. We attribute this enhanced FUV emission to dust scattering of the stellar photons, mostly from the background field stars with small contributions from the central star Spica. While the region is optically thin in general, the FUV intensity did not correlate well with the dust extinction level, indicating that the local radiation field has significant fluctuations. On the other hand, the GALEX FUV intensity well with the $H{\alpha}$ intensity as well as the dust extinction level in the northern part. In fact, the neutral hydrogen column density correlated very well with the dust extinction level throughout the whole region in consideration. The relationship between the neutral hydrogen column density and the color excess was estimated to be ${\sim}7{\times}10^{21}atoms\;cm^{-2}$, which is a little higher than the previous observations made for a diffuse interstellar medium. The spectral analyses of the FIMS observations showed the enhanced C IV emission throughout the whole region, indicating that the C IV emission arises by the interaction of the hot gases with the shell boundaries. A simple model showed that a large portion of the C IV emission comes from the Loop I side of the interaction zone, compared to the Local Bubble side. The FIMS spectrum also showed indications of the molecular hydrogen fluorescence lines for the interaction zone.

  • PDF

A Study on the Development Activation Plan of Housing Cultural Center as Local Complex Community Center (주택문화관의 지역복합커뮤니티센터로서의 활용가능성에 관한 연구)

  • Shin, Hae-Chul;Park, Kyung-Nan;Kim, Moon-Duck
    • Proceedings of the Korean Institute of Interior Design Conference
    • /
    • 2008.05a
    • /
    • pp.116-122
    • /
    • 2008
  • As a model house has attempted a role change from a conceptual perspective as a housing cultural center starting from the 90ties, it began to direct the change into a high end building. In particular, large construction companies have recently invested on an unimagined scale, unlike in the past, in building a model house and pursued the construction of new attractions of cities as well as the upgrade of a brand image by hiring and implementing the designs of celebrity architects or designers. In addition, they have been in pursuit of a change by enhancing the satisfaction and pride of residents by offering spaces and programs for various cultural arts for apartment residents or potential customers and having them participate in those programs. This study aims to expound on the possibility of the utilization of a housing cultural center as a local complex community center by analyzing the spatial organization and the operational program of a housing cultural center appearing since the 90ties. With this aim, the study analyzed the cases of a complex community center and the program and the operational method of a housing cultural center within the case study in order to propose the possibilities for the utilization of a local complex community center. The elevation of the cultural and economic level of citizens and a rapid social change are shown as various demands for welfare, and the subsequent social physical change has led to the expansion of a space as a complex community. A housing cultural center is also directed to grow as a complex community center from the perspective of diverse demands and participations of consumers, and prepares a field for a broad spectrum of communications from the perspective of housing and cities.

  • PDF

Lofargram fusion methods based on local anisotropy (국부 비등방성에 기반한 LOFAR그램 융합 방법)

  • Kim, Juho;Ahn, Jae-Kyun;Cho, Chomgun;Lee, Chul Mok;Hwang, Soobok
    • The Journal of the Acoustical Society of Korea
    • /
    • v.38 no.1
    • /
    • pp.128-138
    • /
    • 2019
  • In this paper, we present fusion methods for two different lofargrams. Since the conventional method synthesizes the lofargrams using frequency spectrum, it has limited performance in fusion of tonal signals which have two-dimensional information of the time-frequency domain. Proposed algorithm uses a two-dimensional directional bilateral filter for preprocessing and fuses two lofargrams based on comparison of local anisotropy of the lofargrams. After noise is suppressed and tonals are sharpened, the local anisotropy can be used as a criterion to divide tonals and noise. The experiment results using simulated data and real data showed that the proposed algorithms result in similar or lower noise level of the fused lofargram than conventional algorithms and decrease tonal omission in fusion process.

Physical modeling of dust polarization spectrum by RAT alignment and disruption

  • Lee, Hyeseung;Hoang, Thiem
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.46 no.2
    • /
    • pp.38.1-38.1
    • /
    • 2021
  • Dust polarization depends on the physical and mechanical properties of dust, as well as the properties of local environments. To understand how dust polarization varies with grain mechanical properties and the local environment, in this paper, we model the wavelength-dependence polarization of starlight and polarized dust emission by aligned grains by simultaneously taking into account grain alignment and rotational disruption by radiative torques (RATs). We explore a wide range of the local radiation field and grain mechanical properties characterized by tensile strength. We find that the maximum polarization and the peak wavelength shift to shorter wavelengths as the radiation strength U increases due to the enhanced alignment of small grains. Grain rotational disruption by RATs tends to decrease the optical-near infrared polarization but increases the ultraviolet polarization of starlight due to the conversion of large grains into smaller ones. In particular, we find that the submillimeter (submm) polarization degree at 850㎛(P850) does not increase monotonically with the radiation strength or grain temperature (Td), but it depends on the tensile strength of grain materials. Our physical model of dust polarization can be tested with observations toward star-forming regions or molecular clouds irradiated by a nearby star, which have higher radiation intensity than the average interstellar radiation field. Finally, we compare our predictions of the P850-Td relationship with Planck data and find that the observed decrease of P850 with Td can be explained when grain disruption by RATs is accounted for, suggesting that interstellar grains unlikely to have a compact structure but perhaps a composite one. The variation of the submm polarization with U (or Td)can provide a valuable constraint on the internal structures of cosmic dust

  • PDF

Study of Structural Stability and Seismic Performances of 4-Way Sway Prevention Brace (4방향흔들림방지버팀대의 구조 안정성 및 내진 성능 연구)

  • O, Soo Un;Lee, Hang Jun;Choa, Sung Hoon
    • Journal of the Society of Disaster Information
    • /
    • v.18 no.3
    • /
    • pp.646-659
    • /
    • 2022
  • Purpose: In this study, we developed a 4-way sway prevention brace that efficiently reduces the installation area and has excellent stability and seismic performance compared to the conventionl sway prevention brace used in existing firefighting facilities. The performance and reliability of the developed 4-way way prevention brace were analyzed by the tensile, compression tests and seismic tests. Method: As the static test, 4-way sway prevention braces were installed on the horizontal and vertical pipes to perform the tensile and compression tests based on the KFI certification standard and the maximum movement was measured at the rated load. As a dynamic test, 4-way sway prevention braces were installed in the pipes filled with water, and the test response spectrum to the input excitation wave were measured through the acceleration sensors. After the seismic tests, separation, failure, and local deformation of the pipes, and 4-way sway prevention braces were not observed. Result: The results of the tensile and compression tests indicated that the maximum movement of the pipe during tension and compression was 50% to 70% or less compared to the certification values, indicating that the performances of the 4-way sway prevention braces were very excellent. The results of the the seismic tests indicated that the test response spectrum of the 4-way sway prevention braces is within the required response spectrum. Conclusion: In this study, it was found that the 4-way sway prevention braces satisfied the KFI certification standard and were superior compared to the existing sway prevention brace in terms of the stability, cost, and installation area.

Development of Site Classification System and Modification of Site Coefficients in Korea Based on Mean Shear Wave Velocity of Soil and Depth to Bedrock (기반암 깊이와 토층 평균 전단파속도를 이용한 국내 지반분류 방법 및 지반 증폭계수 개선)

  • Kim, Dong-Soo;Lee, Sei-Hyun;Yoon, Jong-Ku
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.28 no.1C
    • /
    • pp.63-74
    • /
    • 2008
  • Site response analyses were performed based on equivalent linear technique using the local geologic and dynamic site characteristics, which include soil profiles, shear wave velocity profiles and depth to bedrock for 125 sites collected in Korean Peninsula. From the results of site response analyses, 2-parameters site classification system based on the combination of mean shear wave velocity of soil and depth to bedrock was newly recommended for regions of shallow bedrock depth in Korea. First, as the borders of bedrock depth (H) for site classification were determined as 10m and 20m, the soil sites were divided into 3 classes as $H_1$, $H_2$ and $H_3$ sites. And then, the 3 site classes were subdivided into 7 classes based on the mean shear wave velocity of soil ($V_{s,soil}$). The feasibility of new site classification system was verified and the representative site coefficients ($F_a$ and $F_v$) and design response spectrum were suggested by analyzing uniform trend and dispersion of site coefficients for each site class. The suggested site coefficients and the regression curves present the nonlinear characteristics of soils according to the change of rock outcrop acceleration with uniform trend effectively. From the comparison between the mean values of response spectrum which was acquired from the site response analysis and the suggested design response spectrum, there was a little difference in some of site classes and it was verified to adjust the integration interval to make it more suitable for the site condition in Korea.

Edge Enhanced Error Diffusion based on Gradient Shaping of Original image (원영상의 기울기 성형을 이용한 경계강조 오차확산법)

  • 강태하;황병원
    • Proceedings of the IEEK Conference
    • /
    • 2000.06d
    • /
    • pp.70-73
    • /
    • 2000
  • The error diffusion is good for reproducing continuous image to binary image. However the reproduction of edge characteristics is weak in power spectrum analysis of display error. It is suggested for us an edge-enhanced error-diffusion method that is included pre-processing algorithm for edge characteristic enhancement. Pre-processing algorithm is organized horizontal and vertical directional 2nd order differential values and weighting function of pre-filter. The improved Error diffusion using pre-filter, presents a good results visually which edge characteristics is enhanced. The performance of the proposed algorithm is compared with that of the conventional edge-enhanced error diffusion by measuring the RAPSD of display error, the egde correlation and the local average accordance.

  • PDF

Performance Comparison of Wireless Local Area Network Based on Direct Sequence Spread Spectrum and Impulse Radio (직접 수열 확산 스펙트럼 방식과 임펄스 라디오를 기반한 무선 LAN의 성능 비교)

  • 한병칠;이영효;임성빈
    • Proceedings of the IEEK Conference
    • /
    • 2000.09a
    • /
    • pp.589-592
    • /
    • 2000
  • 무선 LAN은 유선 LAN을 대체하기 보다는 기간망과 이동(Mobile) 사용자간의 수십 미터 이내의 종단 연결점을 제공한다는 개념으로 구성되며, 이동성(Mobility)과 확장성(Scalability)을 발휘할 수 있다는 장점으로 많은 응용 분야에서 각광을 받고 있다. 초광대역 시간 도약(ultra wideband time hopping; UWB/TH) 임펄스 무선기술은 기존 시스템의 정상적인 동작에 거의 영향을 미치지 않기 때문에 별도의 주파수 할당이 필요치 않는 새로운 기술이다. 본 논문에서는 IEEE 802.11의 무선 LAN의 프로토콜을 기적으로 사용하고 전송 방식을 직접수열 확산 스펙트럼 방식을 사용하는 기존의 방법과 임펄스 라디오 방식을 사용하는 경우를 비교하였다.

  • PDF

A Formulation Study on the Combined Preparation of Nitroxynil and Levamisole for Subcutaneous Injection (Nitroxynil과 Levamisole의 피하 주사용 복합제제의 설계에 관한 연구)

  • Oh, Soon-Gyun;Oh, Kyoung-Hee;Kim, Chong-Kook
    • Journal of Pharmaceutical Investigation
    • /
    • v.24 no.1
    • /
    • pp.33-40
    • /
    • 1994
  • In order to develop a broad-spectrum veterinary anthelmintic, a combined preparation of nitroxynil and levamisole was formulated for subcutaneous injection. The preformulation studies on solubilization, physicochemical stability and toxicity of combined preparation were performed. The combined preparation of nitroxynil-N-ethylglucamine and levamisole base could be solubilized up to 50.3%(w/v) of active ingredient concentration in propylene glycol/water system. Injectable solutions were most stable at $4^{\circ}C$. Local toxicities such as flare and edema were not shown when the usual dose of the combined preparation was injected subcutaneously to the rats.

  • PDF

Irradiation Induced Defects in a Si-doped GaN Single Crystal by Neutron Irradiation

  • Park, Il-Woo
    • Journal of the Korean Magnetic Resonance Society
    • /
    • v.12 no.2
    • /
    • pp.74-80
    • /
    • 2008
  • The local structure of defects in undoped, Si-doped, and neutron irradiated free standing GaN bulk crystals, grown by hydride vapor phase epitaxy, has been investigated by employing electron magnetic resonance(EMR), Raman scattering and cathodoluminescence. The GaN samples were irradiated to a dose of $2{\times}10^{17}$ neutrons in an atomic reactor at Korea Atomic Energy Research Institute. There was no appreciable change in the Raman spectra for undoped GaN samples before and after neutron irradiation. However, a forbidden transition, $A_1$(TO) mode, appeared for a neutron irradiated Si-doped GaN crystal. Cathodoluminescence spectrum for the neutron irradiated Si-doped GaN crystal became much broader or was much more broadened than that for the unirradiated one. The observed EMR center with the g value of 1.952 in a neutron irradiated Si-doped GaN may be assigned to a Si-related complex donor.