• 한국인터넷방송통신학회논문지
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• 제11권3호
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• pp.9-15
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• 2011

리플렉트어레이 안테나는 반사경 안테나의 단점을 보완하여 대체할 새로운 형태의 안테나로 대두되고 있다. 하지만 반사판이 단층구조일 경우 대역폭이 매우 좁다는 단점이 있고, 대역폭을 넓히기 위하여 다층구조의 반사판을 사용할 경우 설계가 어렵고 제작 단가가 높아지게 된다. 본 논문에서는 이러한 단점들을 극복하기 위하여 단층구조를 사용하여 제작 단가를 낮추면서 협대역 특성을 극복할 수 있는 정사각형에 U자 모양 슬롯을 낸 패치를 이용하여 리플렉트어레이 안테나를 설계하였다. 제안된 리플렉트어레이 안테나는 12.5 GHz에서 55.5 %의 효율과 14 % 이상의 1 dB gain bandwidth 특성을 갖는다.

• Journal of Computing Science and Engineering
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• 제9권3호
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• pp.134-141
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• 2015

In on-demand multimedia streaming systems, streaming techniques are usually combined with proxy caching to obtain better performance. The patch streaming technique has no start-up latency inherent to it, but requires extra bandwidth to deliver the media data in patch streams. This paper proposes a proxy caching technique which aims at reducing the bandwidth cost of the patch streaming technique. The proposed approach determines media prefixes with high patching cost and caches the appropriate media prefix at the proxy/local server. Herein the scheme is evaluated using a synthetically generated media access workload and its performance is compared with that of the popularity and prefix-aware interval caching scheme (the prefix part) and with that of patch streaming with no caching. The bandwidth saving, hit ratio and concurrent number of clients are used to compare the performance, and the proposed scheme is found to perform better for different caching capacities of the proxy server.

• 한국항해항만학회지
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• 제28권4호
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• pp.299-303
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• 2004

In the Internet, to guarantee transmission rate and delay and to achieve fair bandwidth allocation, many per-flow scheduling algorithms, such as fair queueing, which have many desirable properties for congestion control, have been proposed and designed. However, algorithms based on per-flow need maintain rate state, buffer management and packet scheduling, so that it cost great deal ： implement. Therefore, in this paper, to implement routers cost-effectively, we propose CS-FNE algorithm based on FNE in Core-Stateless network We evaluate CS-FNE comparing with four additional algorithms i.e., CSFQ, FRED, RED and DRR, in several different, configurations and traffic sources. Through simulation results, we show that CS-FNE algorithm can allocate fair bandwidth approximately and is simpler and easier to implement than other per-flow basis queueing mechanisms.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 1999년도 가을 학술발표논문집 Vol.26 No.2 (3)
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• pp.369-374
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• 1999

The problem of bandwidth allocation and routing in VP based ATM networks was studied. A priori reservation of resources for VP's reduces the statistical multiplexing gain, resulting in increased Call Blocking Probability (CBP). The focus of this study is on how to reduce CBP by the efficient bandwidth allocation and routing algorithms. Equivalent capacity concept was used to calculate the required bandwidth by the call. and the effect of traffic dispersion was explored to achieve more statistical gain. A cost-effective traffic dispersion routing algorithm, CED, was designed. The algorithm finds the optimal number of dispersion paths for a call, where the gain balances the dispersion cost. Simulation study showed that CED could significantly reduce the CBP.

• 산업공학
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• 제20권4호
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• pp.427-437
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• 2007

As increasing the Internet traffic, many researches on access network are reported for end-to-end highspeed broadband network, where E-PON (Ethernet-Passive Optical Network) is one of reasonable candidates for the network with respect to cost and bandwidth utilization. For the high-speed access network, E-PON needs an efficient bandwidth allocation method. This paper describes a WFBA (Water-Filling Bandwidth Allocation) algorithm for the efficient bandwidth allocation with various simulation test. Based upon the simulation test, we suggest several ways to improve performance of E-PON.

• 한국통신학회논문지
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• 제39B권11호
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• pp.723-729
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• 2014

본 논문에서는 임의의 선형 재생 부호 앙상블에 대하여 복구 대역폭(Repair bandwidth)과 접속 비용(Repair read cost)의 평균을 유도한다. 한 데이터가 여러 노드에 부호화 되어 분산 저장된 상황에서 하나의 노드가 소실될 경우, 이를 복구하기 위해 필요한 데이터 량을 복구 대역폭, 접속해야 하는 노드 수를 복구 접속 비용이라 한다. 이 때, 선형 재생 부호 앙상블은 데이터 심볼의 수 k와 패리티 심볼의 수 m, 그리고 그들의 차수 분포로 주어진다. 우리는 이러한 부호들이 시스터메틱(Systematic)이며 정확한 복구(Exact repair)를 수행하고 n=k+m개의 모든 저장소(Storages)들이 전부 연결되어 있는 상황을 가정한다. 본 논문의 결과는 파운틴 부호 등과 같이 위와 같은 파라미터들로 랜덤하게 만들어진 부호들에 바로 적용 가능하다. 최종 결과식은 평균 복구 접속 비용이 차수 분포와 n, k에 따라 결정됨을 보여준다.

• ETRI Journal
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• 제24권6호
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• pp.465-468
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• 2002

Ethernet passive optical networks (PONs) are an emerging access network technology that provides a low-cost method of deploying optical access lines between a carrier's central office and a customer site. In this paper, we propose a new algorithm of dynamic bandwidth allocation for multimedia services over Ethernet PONs. To implement the suggested dynamic bandwidth allocation algorithm, we present control message formats that handle classified bandwidths in a multi-point control protocol of Ethernet PONs.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.73-76
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• 2003

The capacity of backbone networks has largely kept pace with the tremendous of growth of Internet traffic. But there has been little progress in the access networks. In this paper, we introduce the access network that is able to offers high bandwidth and its simple protocol. The network architecture is basically multiple ring and use WDM(Wavelength Division Multiplexing), SCM (SubCarrier Multiplexing), and static WADM (Wavelenth Add/Drop Multiplexer) for simplicity, low cost, and offering high bandwidth.

• 전기학회논문지P
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• 제60권4호
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• pp.236-240
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• 2011

Currently one of the most importance issues in industrial sector is energy cost and energy efficiency. The manufacturing plants especially have made many efforts to reduce energy cost by implementing maintenances. But in many cases, they are not aware that how much energy could be saved more. If we know the best energy consumption, which signifies energy baseline, we can control the intensity of maintenances. One way to obtain the baseline is using proper statistics from a specific plant, a sector of industry. Energy bandwidth signifies the gap between actual Specific Energy Consumption(SEC) of a certain plant and minimum SEC of the best plant, and estimate energy saving potential(ESP) is a result of bandwidth analysis. We chose a model plant and implemented some maintenance for a year, and then we obtained ESP. Additionally we could determine the decreased amount of carbon emissions from the plant using Carbon Emissions Factor(CEF) by Intergovernmental Panel on Climate Change(IPCC).

• 한국통신학회논문지
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• 제25권6A호
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• pp.918-926
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• 2000

VoD 서비스를 제공하기 위해서는 대용량의 저장매체와 전송대역이 필요하며 이를 위해서는 막대한 네트워크 구축비용이 필요하다. 이러한 VoD 서비스 구축비용을 줄이기 위한 방법으로 분산 서버 시스템, 멸티캐스트, 프로그램 caching,, 스트림 sharing 등에 관한 연구가 현재 활발히 진행되고 있다. 본 논문에서는 VoD 스트림을 멀티캐스트로 서버스하기 위한 결정기준과 대역폭 감소비율을 도출하였으며, 멀티 캐스트를 이용한 VoD 서비스 시 감소하는 선로 대역폭, 서버의 내부 대역폭과 증가하는 버퍼 용량과의 관계를 분석하여 멀티캐스트의 적용 타당성과 망 구축비용의 감소폭을 비교하였다. 따라서, 본 연구결과는 멀티캐스트를 이용한 VoD 서비스 제공에 적합한 경제적인 선로 설계와 노드 설계에 활용될 수 있을 것으로 기대된다.