• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.10
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• pp.1737-1743
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• 2008

A weather radar extracts the weather information from the return echoes which consist of scattered electromagnetic wave signals from rain, cloud and dust particles, etc. The characteristics of Doppler weather signal and ground clutter should be analyzed to extract the accurate weather information. However, the conventional symmetric weather Doppler model is somewhat inappropriate in representing various weather situations. Therefore, the improved model is suggested to describe the skewness in the Doppler spectrum model. Using the suggested model, many various weather signals can be simulated efficiently in time and spectral domain according to weather situations, operation environment and system characteristics. This simulation method may be very helpful in verifying the accuracy of the weather information extraction algorithms and developing the new system for further performance improvement.

• The Journal of Small Business Innovation
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• v.20 no.3
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• pp.19-30
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• 2017

Today's new engine of economic growth is innovative technology intensive SMEs. However, they have limited access to funding because of asymmetric information problems. Sharing of SME information helps reduce information asymmetry. This paper explains the Korean system of SME technology information sharing, as well as SME credit information sharing. It also provides theoretical analysis about the effects of the SME information sharing on banks' credit analysis activities, based on Karapetyan and Stacescu (2013). Sharing of SME credit and technology information expands the data set of banks and it will enhance their credit analysis. In addition, SME information sharing increases banks' investments in credit analysis activities. To encourage SME information sharing and production, the government can subsidize the production of SME technology information.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.712-714
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• 1999

신규 광대역 멀티미디어 서비스를 효과적으로 제공하기 위한 새로운 망구조 및 전승기술들이 도입되면서, 이러한 시설들 관리할 새로운 시스템들이 요구되고 있다. 본 논문에서는 비대칭 디지털 가입자망을 유지보수관리하기 위한 전산화 방안에 대하여 기술한다. 먼저 성능 감시 및 감독을 위한 객체를 분석하고 이를 바탕으로 시험 관리시스템 및 시험 드라이버의 구조 및 기능을 설계한다. 마지막으로 시험 통신 프로토콜을 정의하고 시험응답의 예를 통한 정보요소 내용을 기술한다.

• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.101-109
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• 2013

Diels-Alder 반응은 유기합성에서 중요하게 다뤄지는 고리형성 반응으로 위치 선택성과 더불어 단일 단계 반응이기에 특이한 입체 선택성을 갖는 것으로 알려졌다. 그러나 실제로는 단계적 반응 경로도 존재할 수 있음을 발견하였는데, 이 경우에 갖는 위치 선택성과 입체 선택성은 달라질 가능성이 높다. Density Functional Theorem(DFT)로 계산한 결과, 비대칭 Diels-Alder 에 대해 단계적 반응의 경우에도 마찬가지로 유사 ortho 형태에 endo 지향성을 나타내었지만 대칭 Diels-Alder 반응에 비해 단계적 반응이 일어나기 힘들다는 결론을 얻을 수 있었다.

• Review of KIISC
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• v.12 no.6
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• pp.12-20
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• 2002

미래의 분쟁은 비대칭적인 형태로 나타날 것이며, 특히 사이버공간에서 사이버수단을 이용하여 전개될 것으로 예측되고 있다. 특히, 군사 강대국들뿐만 아니라 분쟁의 주체가 되는 여러 국가들은 정보전을 새로운 국가 전력의 핵심 요소로 판단하고 관련 능력 확보에 박차를 가하고 있다. 본 고에서는 정보전 위협과 사례를 고찰함으로써 이러한 국제 상황하에서 우리가 대비하여야 할 방향을 정립하는데 도움이 되고자 한다.

• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.361-366
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• 2016

This paper presents an arbitrary impedance transformer with unequal split, based on S- to admittance parameter conversion. When compared even/ odd- mode analysis, the parameter conversion design method constitutes a simple design method to include phase delay information and arbitrary port impedances and asymmetrical configurations. To validate this design method, we designed a 50 to $12.5{\Omega}$ impedance transformer with a 3:1 unequal power split, at an operating frequency of 1 GHz. To implement the proposed impedance transformer, the low impedance transmission lines of calculated result are fabricated by the transmission line connected shunt open stub. Good experimental performances were obtained, in full agreement with simulated results.

• Journal of the Korean Data and Information Science Society
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• v.21 no.5
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• pp.863-871
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• 2010

Until now, many studies related circular data are carried out, but the focuses are mainly on mildly peaked symmetric or asymmetric cases. In this paper we studied a modeling process for sharply peaked asymmetric circular data. By using wrapped Laplace, which was firstly introduced by Jammalamadaka and Kozbowski (2003), and its mixture distributions, we considered the model fitting problem of multi-modal circular data as well as unimodal one. In particular we suggested EM algorithm to find ML estimates of the mixture of wrapped Laplace distributions. Simulation results showed that the suggested EM algorithm is very accurate and useful.

• Journal of the Korean Data and Information Science Society
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• v.21 no.2
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• pp.241-250
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• 2010

Over the past few decades, several studies have been made on the modeling of circular data. But these studies focused mainly on the symmetrical cases including von Mises distribution. Recently, many studies with skew-normal distribution have been conducted in the linear case. In this paper, we dealt the problem of fitting of non-symmetrical circular data with wrapped skew-normal distribution which can be derived by using the principle of wrapping. Wrapped skew-normal distribution is very flexible to asymmetical data as well as to symmetrical data. Multi-modal data are also fitted by using the mixture of wrapped skew-normal distributions. To estimate the parameters of mixture, we suggested the EM algorithm. Finally we verified the accuracy of the suggested algorithm through simulation studies. Application with real data is also considered.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.4
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• pp.655-660
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• 2024

Relay has been applied various communication environments due to its advantages of performance enhancement in communication systems. In this paper, we analyze the performance of a dual-hop communication system which uses one relay by considering asymmetric communication scenarios. The performance is based on bit error rate. Firstly, we compare the overall performance of dual-hop communication system under symmetric and asymmetric, and then analyze the performance depending on the resource allocation. Energy allocation and relay location are considered in the resource allocation. The performance of overall system for each energy allocation and relay location is analyzed. In addition, we analyze the performance of communication system when both energy and relay location are considered simultaneously. Based on the analyzed performance, we discuss the effect of resource allocation for symmetric and asymmetric environments.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1343-1346
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• 2003

상거래와 통신을 위한 주된 매개체로써 등장한 인터넷 뿐 아니라 새로이 대두되는 다양한 유무선 네트워크 환경, 그리고 정보 저장에 있어서 암호화 알고리즘은 보안의 중요한 요소로 자리잡고 있다. 본 논문에서는 대칭 및 비대칭 암호화 알고리즘을 가속시키기 위한 암호화 프로세서의 명령어와 해당 Functional Unit 을 제안하였다. 현재 암호화 알고리즘을 가속시키기 위한 방법으로 사용되는 주문형 반도체(ASIC)는 알고리즘 가속 속도는 빠르지만, 새로운 암호화 알고리즘을 지원할 수가 없고, 지원하는 알고리즘을 사용하지 않는 경우 비효율성을 야기한다. 또한 범용프로세서는 다양하고 새로운 암호화 알고리즘을 지원할 수 있지만 암/복호화 가속속도가 느리다. 이는 암호화 알고리즘이 범용 프로세서에서는 지원하지 연산을 주로 사용하기 때문이다. 따라서 이 논문에서는 대칭 및 비대칭 암호화 알고리즘의 주된 연산을 분석하고, 각각의 연산을 가속시키기 위한 명령어 집합, 그리고 해당하는 Functional Unit을 제안하여 Programmable 한 암호화 프로세서를 설계하기 위한 토대를 마련한다.