• Title/Summary/Keyword: 다중법

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Advanced Rake Receiver for Multiple Access M-ary Modulation UWB System in the IEEE Multipath Channel (IEEE 다중경로 채널에서 다중접속 M진 변조 초광대역 시스템을 위한 개선된 Rake 수신기)

  • An, Jinyoung
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.12
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    • pp.12-19
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    • 2014
  • In this paper, an advanced UWB (ultra wideband) Rake receiving technique based on the statistical distribution model is studied in the M-ary TH-PPM system with multiple access interference (MAI). In order to improve the performance of the Rake receiver, the stochastic model, which can flexibly express the behavior of MAI-plus-noise, is required and the Laplace distribution and the generalized normal Laplace (GNL) model applied by the curtosis matching method are considered. The performance of Rake receiver based on each probability distribution is evaluated in the IEEE multipath fading channel and compared to that of the conventional Rake receiver. The suggested approach shows a superior BER performance than that of conventional Rake receiver.

A study on the implementation of digital anti-fire monitoring system with multipoint communication protocol (다중포인트 통신 프로토콜을 지원하는 디지털 화재 방지 모니터링 시스템 구현에 관한 연구)

  • Kim, Ki-Jung
    • The Journal of the Korea institute of electronic communication sciences
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    • v.7 no.6
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    • pp.1423-1428
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    • 2012
  • In this paper, we investigated an implementation of anti-fire monitoring system based on the RS-485 communication to support local area coverage within a range of 1 Km range. We developed a Multi Point Communication Protocol supporting input/output information processing and control up to 8128 terminal check points, which provides an interface between the anti-fire monitoring system receiver and multiplex transponders. Additionally, a multiplex transponders controller has been designed for the implemented system to comply with the government regulation on fire protection, especially to monitor, report and control 1016 terminal check points within the time limit.

Application of Seismic Analysis and Design Method on the Bridges by Spectral Analysis Method (스펙트럼해석법에 의한 교량의 지진해석 및 설계방법의 적용)

  • 김운학;유영화;신현목
    • Journal of the Earthquake Engineering Society of Korea
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    • v.1 no.2
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    • pp.17-29
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    • 1997
  • Single-mode spectral analysis method is usually applied to a small-scale bridges with the simple geometric shape and uses only fundamental period to estimate the elastic earthquake forces and the displacements of the substructure. On the other hand, multi-mode spectral analysis method may be used instead if the possibilities of potential damage are developed when considering significance, scale, and geometric shape of briages. Since the dynamic responses of bridge can be significantly different depending on the modeling techniques for the restraint and support conditions etc, it may be misled to the unexpected results. In this study the dynamic analysis program which can model and analyze the bridge as a two- or three-dimensional framed structure is developed and verified with the results of other reliable program. Using this program together with the post processor, the designer can easily and readily obtain the reponses(moments, base shears, and displacements)of bridges necessary to design purpose. And further from the analysis results according to the variations of type, scale, and restraint and supprot conditions of bridges including sectional properties, applications of the effective and desirable seismic design are presented.

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A Study on the Improvment of Engine Performance Simulation Using Multi-Length-Scale Model and MOC (특성곡선법과 다중길이 척도법을 이용한 가솔린 기관의 기관성능시뮬레이션 개선에 관한 연구)

  • 김철수
    • Journal of Advanced Marine Engineering and Technology
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    • v.25 no.3
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    • pp.605-616
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    • 2001
  • Generally, there are two methods in researching internal combustion engines. One is by experimental research and the other is by computer simulation. The experimental research has many merits that researchers can get data for engine performance, but it has also some demerit of cost and time. If there is an engine simulation code with accuracy for the solution, it is very convenient to predict the performance and optimum design value of the engine. In this study, engine performance simulation program has been improved to predict the transient variation of properties of gas in cylinder, intake and exhaust manifolds, There total program code was developed to calculate the pressure, flame factor and turbulent intensity, As a result of present study, the authors could predicted the in-cylinder pressure, intake manifold pressure and the engine performance in various conditions. The authors also could easily prepare the tool if optimum design of manifold and in-cylinder geometry.

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An ultra-compact Wilkinson power divider MMIC with an improved isolation characteristic employing RCR design method (RCR 삽입법에 의해 설계된 높은 절연특성을 가지는 초소형 MMIC용 윌킨슨 전력분배기)

  • Yun, Young
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.1
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    • pp.105-113
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    • 2013
  • In this work, using a ${\pi}$-type multiple coupled microstrip line structure (MCMLS) and RCR (Resistor Capacitor Resistor) structure, we fabricated ultra-compact and high isolation Wilkinson power divider on GaAs MMIC (Monolithic Microwave Integrated Circuit). The line length of the Wilkinson power divider was reduced to about ${\lambda}$/46, and its size was 0.304 [$mm^2$], which is 12.1 % of conventional one. Compared with conventional Wilkinson power divider, isolation characteristic of the proposed Wilkinson power divider was highly improved by using RCR insertion method. The proposed Wilkinson power divider showed good RF performances in C/X band.

Detection of multiple change points using penalized least square methods: a comparative study between ℓ0 and ℓ1 penalty (벌점-최소제곱법을 이용한 다중 변화점 탐색)

  • Son, Won;Lim, Johan;Yu, Donghyeon
    • The Korean Journal of Applied Statistics
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    • v.29 no.6
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    • pp.1147-1154
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    • 2016
  • In this paper, we numerically compare two penalized least square methods, the ${\ell}_0$-penalized method and the fused lasso regression (FLR, ${\ell}_1$ penalization), in finding multiple change points of a signal. We find that the ${\ell}_0$-penalized method performs better than the FLR, which produces many false detections in some cases as the theory tells. In addition, the computation of ${\ell}_0$-penalized method relies on dynamic programming and is as efficient as the FLR.

Multivariate Statistical Analysis and Prediction for the Flash Points of Binary Systems Using Physical Properties of Pure Substances (순수 성분의 물성 자료를 이용한 2성분계 혼합물의 인화점에 대한 다변량 통계 분석 및 예측)

  • Lee, Bom-Sock;Kim, Sung-Young
    • Journal of the Korean Institute of Gas
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    • v.11 no.3
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    • pp.13-18
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    • 2007
  • The multivariate statistical analysis, using the multiple linear regression(MLR), have been applied to analyze and predict the flash points of binary systems. Prediction for the flash points of flammable substances is important for the examination of the fire and explosion hazards in the chemical process design. In this paper, the flash points are predicted by MLR based on the physical properties of pure substances and the experimental flash points data. The results of regression and prediction by MLR are compared with the values calculated by Raoult's law and Van Laar equation.

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A Study on the Optimal Conditions by Means of Experimental Design for Preparation of Starch/PVA Blends 2. Multiplex Mixture Optimal Method (실험계획법을 이용한 전분/PVA 블렌드 제조 최적조건 탐구에 관한 연구 2, 다중혼합물 최적법)

  • Hong, young-Keun;Lee, Myoung-Seok
    • Elastomers and Composites
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    • v.41 no.1
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    • pp.3-9
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    • 2006
  • Optimal conditions for preparation of starch/PVA blends were investigated with the consideration of factors that may influence mechanical properties of the blends. Multiplex mixture optimal method as a statistical method were performed and then tensile strength, strain at break, Young's modulus and tear strength of films of the blends were measured to determine the optimal conditions for preparation. The mechanical properties needed for the degradable agricultural mulch were the target of this experiment. Results showed that although the strain at break was a little insufficient, the other properties were very close to the target. This means that the mechanical properties of the film from this blend as a whole are very compatible with those of the reference mulch.

Performance Analysis Based On Log-Likelihood Ratio in Orthogonal Code Hopping Multiplexing Systems Using Multiple Antennas (다중 안테나를 사용한 직교 부호 도약 다중화 시스템에서 로그 우도비 기반 성능 분석)

  • Jung, Bang-Chul;Sung, Kil-Young;Shin, Won-Yong
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.12
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    • pp.2534-2542
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    • 2011
  • In this paper, we show that performance can be improved by using multiple antennas in the conventional orthogonal code hopping multiplexing (OCHM) scheme, which was proposed for accommodating a larger number of users with low channel activities than the number of orthogonal codewords used in code division multiple access (CDMA)-based communication systems through downlink statistical multiplexing. First, we introduce two different types of OCHM systems together with orthogonal codeword allocation strategies, and then derive their mathematical expression for log-likelihood ratio (LLR) values according to the two different schemes. Next, when a turbo encoder based on the LLR computation is used, we evaluate performance on the frame error rate (FER) for the aformentioned OCHM system. For comparison, we also show performance for the existing symbol mapping method using multiple antennas, which was used in 3GPP standards. As a result, it is shown that our OCHM system with multiple antennas based on the proposed orthogonal codeword allocation strategy leads to performance gain over the conventional system---energy required to satisfy a target FER is significantly reduced.