• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.12
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• pp.848-855
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• 2019

Eco-friendly gas turbine combustors are getting attention due to emission regulations. Swirler is important design factor for flame stability and flashback inside the combustor. Design methods of the axial swirler and the radial swirler were discussed and the suitability of the swirl number calculation considering the geometric design variables and the flow loss was examined in the radial swirl for gas turbine combustor. The swirl number of flow was calculated by computational fluid dynamics and compared with swirl number according to each design method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10B
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• pp.919-927
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• 2008

The growing availability of broadband multimedia applications are providing strict real-time services and enabling users to feel much interactivity as well as 'sense of presence'. In that sense, there would be increased demand for what network and system have to do to fulfill the user expectations. In this paper, we implement a real-time multimedia application which make use of real-time DXT CODEC and investigate what the challenges of networking and system are. We carry out various experiments over a research network test-bed to evaluate the performance of our proposals.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.2
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• pp.206-216
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• 2000

In this paper, the linear tapered slot(LTS) antenna and linear constant tapered slot(LCTS) antenna are optimized for millimeter-wave antenna by the finite difference time domain(FDTD) method and then fabricated and measured. The microstrip-to-slot transition is proposed with the widen $\lambda$/4 open stub as feeder for wide bandwidth of 16.5GHz($VSWR\leq2$). The results of the calculation and measurement, the bandwidth of LTS antanna is 8.3GHz(26.47%) and 7.1792GHz(22.4%) respectively. Also, the bandwidth of LCTS antenna is 8.1GHz(26.47%) and 6.3243GHz(20.43%) respectively.

• Journal of the Korean Data and Information Science Society
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• v.22 no.4
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• pp.735-740
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• 2011

In recent, electronic devices were able to develop and focus for ultra-compact size, intelligence, multifunction and broadband. Their SMPS is realized to ultra-compact size, light weight, high efficiency, high reliability, low noises. The power module which can be used to supply DC output from a commercial power supply (85 to 265 VAC). A switching power supply can be made easily by adding simply external circuit, such as microcontroller, a relay, etc. It would be apply to mostly electronic devices, and fit the global project "Saving energy". But we need to statistical analysis for a quality and performance about a load and an output voltage in product.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.346-351
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• 2001

A new analysis method was proposed, where the even . odd-mode theory for a symmetrical coupled-line directional coupler was applied to a transformer-type directional coupler. In addition, the tap-offs were analyzed by the proposed theory, which are widely used in CATV (Cable Television), DBS (Direct Broad- casting Satellite), CS (Communication Satellite) systems. By comparing the calculation results to the measured ones using the even . odd-mode reflection coefficients only, the validity of the proposed analysis method was confirmed. Then, the tap-off has been broadened from 5 MHz over 4,000 MHz by adopting the proposed theory.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.125-129
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• 2002

In the multimedia age, the development of Internet/Intranet circumstances makes Required Traffic per user be gradually larger. And the more demand getting many pieces of information quickly increases, the more required the rapid network is as a necessary consequence. This is why we need the advanced Ethernet. Gigabit Ethernet has many advantages in many respects. For example, it increases the capacity of network and makes network highly efficient in the existing Ethernet circumstance. Thus, Gigabit Ethernet becomes a counterproposal that can resolve Required Traffic per internet user. Present study inquires the concepts and the characteristics connected with Gigabit Ethernet Technology and analyses the Link efficiency with a hypothetical modeling.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.464-467
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• 2001

There nay be fierce debate over the nature of the medium that will herald the brave new world copper, fiber, wireless or satellite there is little doubt that future networks will be broadband in their capabilities. The Republic of Korea is a significant exception and leads the world, at present, in terms of number of subscribers with broadband access via ADSL. In order to further drive the growth in the broadband Internet access market, the government is scheduled to implement open access for ISPs and unbundling of the local loops of incumbent public telecom operators during the course of 2001. By the Way, Should incumbent telecommunication operators be obliged to provide unbundled access to the local loop\ulcorner

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.983-990
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• 2010

In this paper, we designed and implemented the MIMO antenna for LTE(Long Term Evolution), supposed to be a next generation communications network, DCS1800, DCS1900 and WCDMA. Using conventional monopole antenna with MD material results in good characteristics, miniaturization for LTE band and as well as broadbanding for DCS, WCDMA band. The performance of the proposed MIMO antenna shows VSWR < 2, under -10 dB of isolation and the gain is -1.66 ~ 1.33 dBi for LTE(Long Term Evolution), DCS1800, DCS1900 and WCDMA, which has omnidirectional radiation pattern.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.12B
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• pp.1013-1021
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• 2004

Recently, there have been the rapid increasing needs to integrate high-speed communications and digital TV in home network. To realize the integration of those services, the MIC formulated the broadband convergence network (BcN) plan as one of the new growth engines. The BcN will be implemented by FTTH solutions and these solutions are designed to support digital home network. To develop and promote the BcN, we need to find the bandwidth requirements for home network. This paper will examine the bandwidth requirements in detail to accommodate data traffics for high-speed communications and TV at building intra network and home intra network.

• Proceedings of the KIEE Conference
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• 2005.07e
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• pp.6-11
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• 2005

디지털 경제시대의 웰빙주거문화생활을 위한 욕구 충족추세에 따라서 정보통신서비스는 광대역화 및 이동성을 지향하며 발전하고 있으며, 서비스 및 기기의 융합이 가속화 될 것으로 전망되고 있다. 디지털기술에 의한 서비스, 단말기, 네트워크등 융합의 시발점은 가정이며, 가정에서 정보를 편안하게 이용하고, 즐길 수 있도록 제공하는 방법이 주거용 건물의 디지털 네트워크 구축기술이라 할 수 있다. 이와 같은 디지털 융합 패러다임에 의해, 전개되는 새로운 정보통신환경에 적극적으로 대응하기 위해서 정보통신부에서는 세계 최고의 IT 인프라 환경을 기반으로 국민의 삶의 질과 정보화의 혜택을 극대화 할 수 있도록 정보화촉진전략을 추진한 결과, 수요자 정보인프라는 기존 정부정책에서 일부 소외되어 왔음을 보여준다. 이제부터는 디지털경제의 공급측면의 인프라 수준만큼 수요측면의 양적 질적 성장을 끌어올리는 일만이 남아있다. 기술과 시장 변화는 무엇보다도 정부정책 및 규제의 변화를 필요로 한다. 따라서 디지털홈의 정보가전 기기간 상호운용성이 보장되는 표준화로 네트워크가 구축되어야 하며, 표준과 연계된 기술이 지속적으로 개발되어야 한다. 본 발표내용에서는 최근 발표된 정보통신부의 초고속정보통신 건물인중기준과 각 지방자치단체에서 실시하는 정보통신설비 사용전검사기준에 적합한지 여부에 관해 문제점을 검토 기술하였다.