• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.22 no.1
• /
• pp.121-126
• /
• 2022

This study is about an antenna implemented in the form of a monopole having a hexagonal symmetric pattern by simplifying the modified Hilbert curve fractal monopole structure. The modified Hilbert curve fractal monopole structure was simplified and miniaturized, and the radiator was implemented in a hexagonal symmetrical pattern to improve performance. The dielectric constant of substrate is 4.7, and the total line length with a meander-shaped symmetrical structure is 59 mm. The size of the antenna is 10 mm × 10 mm × 0.8 mm, and the line width is 0.4 mm. The size of the antenna measuring jig is 64 mm × 21 mm × 1 mm. The resonant frequency is 1.57 GHz, and the frequency range is 1.51 to 1.615 GHz. The frequency bandwidth is 105 MHz. As for the antenna gain, the measurement gain of the YZ-plane was 2.32 dBi, and that of the XZ-plane was -1.03 dBi. As a result, we confirmed that antenna miniaturization is possible using a hexagonal symmetric pattern fractal structure. In addition, we confirmed that the antenna performance can be easily improved by changing the structure of the radiator.

• Journal of the Korean Institute of Gas
• /
• v.25 no.6
• /
• pp.7-13
• /
• 2021

Various research has been done on fires and explosions at gas stations at home and abroad. However, only studies of off-site damage in the event of fire at the gas station were conducted, and research on fire at the auxiliary facilities in the gas station was insufficient. The gas station is a place where anyone can easily access dangerous goods. As the risk of fire increases due to the recent increase of auxiliary facilities such as convenience stores and car repair shops in gas stations, it is important to detect the effects of fire on the main oil refinery in case of fire and to verify the validity of existing regulations. In this thesis, we conducted a study to find out the effect of radiation heat on the separation between fixed and fixed oil reactors in the event of fire at an auxiliary facility. Simulation was modelled using FDS 5.5.3 Version, and the size of the fire source was configured with 13 fire assessment devices and the heat emission rate per unit area was entered. Simulation shows that the separation distance of 2 m does not secure the safety of the gas pump in the event of fire at the auxiliary facilities, and radiation heat does not damage at the separation distance of at least 4 m. Accordingly, facilities that can block radiant heat in the event of fire at auxiliary facilities, and measures to limit the use of auxiliary facilities or to re-impose the separation between buildings and fixtures will be needed.

• Proceedings of the Korean Society for Information Management Conference
• /
• 1994.12a
• /
• pp.173-176
• /
• 1994

최근 정책적 한계점에 직면한 서울시 새마을 이동문고의 운영 실태분석을 통한 활성화방안을 제시하고자 한다. 운영방법은 봉사대상 계층을 다양화, 전문화하고 순회시기는 지역별에서 이용자 확대를 위해 AM10-12. 50.6% PM 2-4, 38.2% 비율을 보인다. 순회지역은 유효봉사 반경기준을 200m로 제한 할것과 문고 차량에 컴퓨터, FAX, 복사기, 전화, CD-ROMㆍ리더기 등 탑재할 것을 요청하고 있다. 이동문고당 대출실적 아파트지역 76%, 일반주택 12%, 신규이용율 18%, 재이용 33% 증가되었다. 운영부서는 일정비율을 할당할 것등을 분석결과로 밝히고 있다.

• Journal of Advanced Marine Engineering and Technology
• /
• v.18 no.1
• /
• pp.32-40
• /
• 1994

The radiative heat transfer analysis in particle layer has an inherent difficulty in treating the governing integro-differential equations, which are derived from the remote effects. Most of the existing analyses are limited to the one dimensional system, taking into account only absorption or isotropic scatting of solid particles. Fortunately, a new Monte Carlo Simulation method is recently developed to analyse multidimensional radiative heat transfer in particles with anisotropically scatting. By this method, the present study analyses the radiative heat transfer in dispersed particles through the numerous droplets in the liquid droplet radiator to develop a technique of liquid droplet radiator. Consequently, knows that the radiative heat flux in particle layer is influenced by exitinction coefficient, optical thickness and surface area of particles in the system.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.35S no.1
• /
• pp.105-113
• /
• 1998

A new image processor is implemented for high-speed digital copiers and facsimiles. The imgage processor performs CCD and CIS interface, pre-processing, enlargement andreduction of gray level image, and various halftoning algorithms. Implemented halftoning algorithms are simple thresholding, fuzzy based mixed mode thresholding, dithering, and edge enhanced error diffusion. The result of binarization is transferred to a printer with serial or paralel output ports. Line by line pipelined data prodessing architecture is employed with time sharing access of the external memory. In receiving mode, it converts the resolution of received binary image for compatibility with conventional facsimile. In copy mode, a line of A3 paper with 400 dpi is processed with in 2.5 ms. The prototype of image processor was implemented usig Laser Programmable Gate Array (LPGA) with 0.8.mu.m technology.

• The Optical Journal
• /
• s.108
• /
• pp.57-61
• /
• 2007

국내 광산업은 80년대 카메라, 복사기 등 결상기기 중심에서 90년대 이후에는 결상기기와 더불어 레이저가공기, 광정보기기, 광통신기기 등 광응용기기로 확대되고 있다. 2005년 기준으로 볼때 국내 광산업은 세계시장의 약 5.5%를 차지했으며, 정밀 광산업 기술로드맵과 직접 관련되는 광정밀기기, 광정보기기, 광학기기분야의 수입은 68%, 수출이 90%를 차지해 수출역점산업임을 알 수 있다. 따라서 2010년에는 광산업 세계 시장 규모가 400조원 수준에 이를 것으로 예상되는 가운데 이에 대비하여 국내 광산업의 성장기틀을 다질 때이다. 본 고는 한국광학기기협회에서 작성한 정밀광학기기 분야의 기술로드맵 내용중 국내 광산업 시장 전망과 국내 기술 현황에 대한 내용을 발췌, 정리한 것이다.

• Proceedings of the SAREK Conference
• /
• 2008.11a
• /
• pp.330-333
• /
• 2008

The hybrid air-conditioner, where air is cooled both by convection and radiation, is developed. The indoor unit of the air-conditioner consists of radiation panel and dehumidification coil, where refrigeration R-134a is supplied by independent refrigeration cycles. Optimum refrigerant charge was 750g for both cycles. Optimum evaporation pressure was 3.7 bar for the radiation panel cycle and 3.9 bar for the dehumidification cycle. The cooling capacity of the radiation panel was 1.01 kW and that of the dehumidification coil was 0.94kW, which yielded COP of 3.3.

• The Korean Journal of Zoology
• /
• v.37 no.1
• /
• pp.104-112
• /
• 1994

한국산 야생 생쥐(Mus muscurus subspecies)와 동계교배 계통인 BALB/c의 정모세포에서 감수분열에 따른 염색체의 chiasma 말단화 여부와 chiasma 빈도, X-Y 염색체의 조기 분리 빈도 등을 조사하였다 한국산 야생 생쥐에서는 chiasma 말단화가 일어나지 않는 것으로 나타나 말단 chiasma는 말단 부위에 특이적으로 생긴 chiasma로 생각되며, chiasma 빈도의 감소와 univalent 빈도의 증가에 관한 ageing의 영향도 관찰되지 않았다. 불임개체에서 X-Y 염색체 조기 분리가 낮은 빈도로 나타나 동계교배 계통과는 다소 상반된 결과를 보였고, chiasma 빈도는 한국산 야생 생쥐가 동계교배 계통에 비해 다소 높게 나타났으며 복사기, 이동기 및 중기 1을 거치는 동안 거의 일정한 수준을 보여주었다. 또한 한국산 야생 생쥐에서 특징적으로 개재 chiasma 빈도 보다 말단 chiasma 빈도가 높게 나타났으며 이에 대해서는 부가적인 연구가 뒤따라야 할 것으로 사료된다.

• Aerospace Engineering and Technology
• /
• v.6 no.1
• /
• pp.222-229
• /
• 2007

Environmental tests should be carried out to show that design performance is in an operational condition in an actual operational environment to assure maintainability and reliability. Aero-products electromagnetic compatibility tests are performed mainly for the individual parts and Specifications MIL-STD-461E and RTCA DO-160E are developed for the military and commercial parts tests respectively. The MIL-STD-461E which is a military environmental test standard is targeting all munitions and that user can apply by selecting applicable requirements from this specification. On the other hand, requirements are applied exclusively for the Avionics Equipments in commercial test standard.

• Proceedings of the Korean Information Science Society Conference
• /
• 2001.04a
• /
• pp.133-135
• /
• 2001

본 논문에서는 MPEG-2 프로그램 스트림(Program Stream)을 위한 A/V(Audio/Video) 편집기를 제안하고 구현하였다. 이 편집기에서는 사용자가 일반 문서를 편집하듯이 간단한 조작만으로 스트림(Stream)을 복사(Copy), 자름(Cut), 삭제(Delete), 붙이기(Paste)가 가능하며, 또한 스트림 내에서 임의로 조합하여 새로운 스트림을 생성할 수 있는 조합기능도 제공된다. 기존 편집기의 복잡성을 감소시키고 사용자가 접근하기 쉽도록 제작되었으며, 계산량을 현저히 줄임으로써 보다 향상된 성능을 제공할 수 있다.