• 전자공학회논문지S
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• 제35S권10호
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• pp.144-155
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• 1998

임의의 잡음 환경에서 신호 대 잡음비 (SNR; signal-to-noise ratio) 를 최대화하는 어레이 안테나 소자의 최적 가중치들은 안테나의 설계 구조와 안테나로 유입되는 표적 및 간섭 신호의 방향에 의해 결정된다. 신호 대 잡음비를 최대화시키는 방법을 이용한 기존의 부엽제거기법들은 고-전력 간섭 신호시 주 안테나의 부엽으로 수신된 간섭 신호가 매우 커서 주 안테나 수신 시스템을 포화시키므로 수신 신호 성분이 손실된다. 본 논문에서는 강한 간섭 신호에 의해 주 안테나 수신 시스템이 포화되는 것을 막기 위해 수신기 전단에서 강한 간섭 신호를 일차적으로 제거하는 적응 영 조정 기법(adaptive nulling)을 주 안테나에 적용한다. 또한, 제거할 간섭 신호를 충분히 획득하기 위해 간섭 신호 방향 적응 어레이 기법(adaptive array)을 보조 안테나에 적용한다. 제안한 부엽제거기법은 이 주/보조 안테나의 출력을 부엽제거기(SLC; sidelobe canceller)의 입력으로 사용한다. 적응 영 조정기와 적응 어레이의 결합으로 구성된 제안한 부엽제거기는 강한 간섭 신호에 의해 주 안테나 수신 시스템이 포화되는 것을 막음으로서 주어진 모의 실험 신호에 대해 기존의 부엽제거기들보다 부엽에서 평균 7 dB, 주빔 근처에서 약 20 dB 이상의 신호 대 잡음비를 개선하였다.

• 전기학회논문지
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• 제56권1호
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• pp.188-196
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• 2007

In this paper we propose an efficient offset curve generation algorithm for open and closed 2D point sequence curve(PS curve) with line segments in the plane. One of the most difficult problems of offset generation is the loop intersection problem caused by the interference of offset curve segments. We propose an algorithm which removes global as well as local intersection loop without making an intermediate offset curve by forward tracing of tangential circle. Experiment in computer sewing machine shows that proposed method is very useful and simple.

• Journal of the Optical Society of Korea
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• 제20권2호
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• pp.245-250
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• 2016

In this paper, we demonstrate a self-imaging technique that can visualize longitudinal interference patterns behind periodically-structured objects, which is often referred to as Talbot carpet. Talbot carpet is of great interest due to ever-decreasing scale of interference features. We demonstrate experimentally that Talbot carpets can be imaged in a single exposure configuration revealing a broad spectrum of multi-scale features. We have performed rigorous diffraction simulations for showing that Talbot carpet print can produce ever-decreasing structures down to limits set by mask feature sizes. This demonstrates that large-scale pattern masks may be used for direct printing of features with substantially smaller scales. This approach is also useful for characterization of image sensors and recording media.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권1호
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• pp.112-117
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• 2016

This paper presents a half-rate current-integrating DFE receiver with sub-unit interval (sub-UI) inter-symbol interference (ISI) cancellation. By having a single additional DFE tap in each data path, the proposed DFE receiver can minimize BER degradation due to input pattern dependency and feedback tap latency problems in conventional current-integrating DFE receivers. The proposed DFE receiver was designed and fabricated in a 45 nm CMOS process, whose measurement results indicated that the BER bathtub width is increased from 0.235 UI to 0.315 UI (34% improvement) at $10^{-12}$ BER level.

• 음성과학
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• 제6권
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• pp.7-24
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• 1999

Eleven Korean learners of English took part in an experiment where the production and perception of English /r/ and /l/ in four different word positions was investigated. Overall the subjects made more errors on /l/ in both production and identification tests. The frequency of the subjects' errors was also sensitive to word positions in which the two English liquids occur. Especially the subjects made noticeably fewer errors in intervocalic medial position. It is suggested that the Korean subjects' acquisitional pattern in this particular case of foreign phone learning can be explained more by language particular 'interference' effects rather than 'universal' acoustic arguments such as those given in Dissosway et a1. (1982) and Sheldon and Strange (1982). The results of the experiment also support the minority position among second language educators that in some cases of non-native phone acquisition, learners' production abilities can be developed earlier than their perceptual abilities.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1994년도 춘계공동학술대회논문집; 창원대학교; 08월 09일 Apr. 1994
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• pp.291-300
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• 1994

In this paper we consider the frequency assignment problem (FAP) in a cellular mobile communication system which has a maximal distance of channel interference. This special structure is observed in most cellular systems. To handle the considered FAP, we use the pattern approach which fits naturally to the problem. Based on this approach, we are able to formulate the considered FAP into a manageable optimization problem and propose a two phase heuristic algorithm for the problem. Computational experiments show that our algorithm performs much better in both solution quality and computational time than the recently developed algorithms for FAP. Since the considered FAP well reflects most cellular systems, our algorithm can be applied to many practical situations.

• 정보통신설비학회논문지
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• 제8권4호
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• pp.201-206
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• 2009

The third generation mobile communications system requiring the reliable multimedia data transmission has provided with the reliable voice, data and video services over the variable propagation environment. However the broadband wireless multiple access technologies cause Inter Symbol Interference (ISI) or Multiple Access Interference (MAI) to degrade the performance of W-CDMA (Code Division Multiple Access) system. Constant Modulus Algorithm (CMA) which is frequently used as the adaptive blind equalizers to remove the interfering signal has ill-convergence phenomenon without proper initialization. In this paper, new blind equalization method based on conventional CMA is proposed to improve the channel efficiency, and through computer simulation this is tested over the time varying fading environment of mobile communication system. Consequently, new blind equalization method into concatenated Kalman filter with CMA is verified better than conventional CMA through adopting minimum mean square errors and eye-pattern obtained from algorithm are compared.

• Journal of the Optical Society of Korea
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• 제19권6호
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• pp.555-559
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• 2015

Coherence length (time) is a key parameter in many classical and quantum optical applications. Two interferometers – Michelson and Young’s double-slit – are used to characterize the temporal coherence of single photons emitted from single terrylene molecules. For quantitative analysis, a dispersion-related distortion in the interference pattern of a Michelson interferometer is carefully corrected by a simple dispersion compensation. Additionally, it has been demonstrated that Young’s interferometer can be used in temporal coherence studies at the single photon level with high accuracy. The pros and cons of the two systems are discussed. The measured coherence lengths in the two systems are consistent with one another under the self-interference interpretations.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1956-1959
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• 2002

Power control (PC) on the reverse link of CDMA cellular system is important to increase system capacity. PC eliminates fluctuations in the received signal level and hence reduces the required signal-to-interference ratio. However, both perfect PC and imperfect PC depend on number of interferences as number of users, which by using smart antenna system can decrease number of interferences in any directions except interferences from the main beam direction. In this paper , number of elements in smart antenna system, which directly relates to the main beam pattern, is studied to find the effects on the outage probability , bit energy-to-interference density ratio (Eb/Io) and the capacities of both perfect and imperfect PC.

• Journal of the Optical Society of Korea
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• 제6권3호
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• pp.83-86
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• 2002

Nanoscopic emission from periodic nano-hole arrays in thick metal films is studied experimentally. The experiments give direct evidence for SP excitations in such structures. We show that the symmetry of the emission is governed by polarization and its shape is defined the interference of SP waves of different diffraction orders. Near-Held pattern analysis combined with the far-Held reflection and transmission measurements suggests that the SP eigenmodes of these arrays may be understood as those of ionic plasmon molecules.