• Title/Summary/Keyword: Input Capacity

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Channel Capacity of BLAST based on the Zero-Forcing criterion (Zero-Forcing 기반의 BLAST 채널 용량)

  • Lee, Heun-Chul;Kim, Hee-Jin;Lee, In-Kyu
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.12
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    • pp.34-41
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    • 2008
  • In this paper, we present an asymptotical analysis of channel capacity of Bell labs layered space-time (BLAST) architectures based on a zero-forcing (ZF) criterion in the sense of signal-to-noise ratio (SNR). We begin by introducing a new relationship related to multi-input multi-output (MIMO) channel capacity. We prove that Diagonal Bell Labs Space-Time (DBLAST) attains the lower bound for MIMO channels when interference nulling is carried out based on the ZF-criterion. An exact closed-form expression for the probability density function of the channel capacity is analyzed. Based on the asymptotic behavior of the channel capacity of each layer, closed-form expressions for the asymptotic ergodic capacity are derived for BLAST. Based on the analysis presented in this paper, we gain an insight on the channel capacity behavior for a MIMO channel. Computer simulation results have verified the validity and accuracy of the proposed analysis for a wide range of antenna array sizes.

Optimal Number of Base Station Antennas and Users in MF Based Multiuser Massive MIMO Systems (MF 기반 다중 사용자 Massive MIMO 시스템의 최적 기지국 안테나 수 및 사용자 수 분석)

  • Jung, Minchae;Choi, Sooyong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.8
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    • pp.724-732
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    • 2013
  • In this paper, we analyze a performance of multiuser massive multiple-input and multiple-output (MIMO) system. We derive the ergodic cell capacity based on a downlink frame structure and analyze the ergodic cell capacity with respect to the number of base station (BS) antennas and the number of users. This paper shows that the ergodic cell capacity is a concave function with respect to the number of BS antennas and the number of users, and also derives the optimal numbers of BS antennas and users for the maximum cell capacity. The simulation results verify the derived analyses and show that the derived numbers of BS antennas and users provide the maximum cell capacity.

Cost-based optimization of shear capacity in fiber reinforced concrete beams using machine learning

  • Nassif, Nadia;Al-Sadoon, Zaid A.;Hamad, Khaled;Altoubat, Salah
    • Structural Engineering and Mechanics
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    • v.83 no.5
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    • pp.671-680
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    • 2022
  • The shear capacity of beams is an essential parameter in designing beams carrying shear loads. Precise estimation of the ultimate shear capacity typically requires comprehensive calculation methods. For steel fiber reinforced concrete (SFRC) beams, traditional design methods may not accurately predict the interaction between different parameters affecting ultimate shear capacity. In this study, artificial neural network (ANN) modeling was utilized to predict the ultimate shear capacity of SFRC beams using ten input parameters. The results demonstrated that the ANN with 30 neurons had the best performance based on the values of root mean square error (RMSE) and coefficient of determination (R2) compared to other ANN models with different neurons. Analysis of the ANN model has shown that the clear shear span to depth ratio significantly affects the predicted ultimate shear capacity, followed by the reinforcement steel tensile strength and steel fiber tensile strength. Moreover, a Genetic Algorithm (GA) was used to optimize the ANN model's input parameters, resulting in the least cost for the SFRC beams. Results have shown that SFRC beams' cost increased with the clear span to depth ratio. Increasing the clear span to depth ratio has increased the depth, height, steel, and fiber ratio needed to support the SFRC beams against shear failures. This study approach is considered among the earliest in the field of SFRC.

Clamped capacitance control of a piezoelectric single crystal vibrator using a generalized impedance converter circuit (범용 임피던스 변환회로를 이용한 압전 단결정 진동자의 제동용량 제어)

  • Kim, Jungsoon;Kim, Moojoon
    • The Journal of the Acoustical Society of Korea
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    • v.37 no.1
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    • pp.46-52
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    • 2018
  • The piezoelectric single crystals used in piezoelectric transformers have a problem that power transfer capacity is comparatively low due to their high input impedance. In this study, we suggest a method to improve the power transfer capacity by reducing the high input impedance of the piezoelectric single crystal vibrator by connecting a capacitance increasing circuit to the electrical terminals of the piezoelectric single crystal vibrator where the circuit is a GIC (Generalized Impedance Converter) circuit using operational amplifiers. The result of measuring driving characteristics after applying the designed capacitance increasing circuit to the $128^{\circ}$ rotated Y-cut $LiNbO_3$ crystal vibrator confirmed that the input impedance decreased by 25 %, electromechanical coupling factor increased by 30 %, and the power transfer capacity increased by about 17 to 30 times in voltage conversion characteristics.

A Effect of Unreliable Default Parameter in Forecasting Delay and Level of Service of Signalized Intersection (초기변수의 불확실성이 신호교차로 지체모형 및 서비스수준 예측에 미치는 영향 분석)

  • Kim, Sung-Deuk;Park, Won-Kyu;Kim, Kyung-Kyu
    • Journal of Navigation and Port Research
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    • v.27 no.4
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    • pp.471-478
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    • 2003
  • In the Signalized Intersection, the capacity analysis is conducted with a large amount of input data such as road way, traffic and signal condition. but the level of service(LOS) is determined by delay estimated as a measure of effectiveness (MOE) based on this procedure. However, It is under the circumstances which are not considered for the errors caused by the uncertainty of input data in the field(the turing volumes, lane geometry, signal timing, grade of approach lane, percentage heavy vehicles, peak hour factor and arrival type etc.) as become the bases in the determination of the capacity and LOS. It includes the problem of reliability which is not verified for the capacity and LOS estimated. So, this study is to suggest the minimization of their influences by examining whether the uncertainty of input data such as the traffic volume, percentage of heavy vehicles and roadway geometry on the approach lane in the intersection under the study affects the capacity analysis and LOS determination.

Modeling and Optimization of RMS Pulse Width for Transmission in Dispersive Nonlinear Fibers

  • Lee, Jong-Hyung
    • Journal of the Optical Society of Korea
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    • v.7 no.4
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    • pp.258-263
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    • 2003
  • Simple algebraic expressions are derived to approximate the optimal input RMS pulse width and the resulting output RMS pulse width in single-mode fibers. The results are compared with the previously published methods and with numerical results by the split-step Fourier method. In addition, for a transform-limited Gaussian input pulse, it is shown that there is no optimum input pulse width to minimize the output spectrum width. Finally, with fiber nonlinearity, it is shown mathematically that there is not an optimum input pulse width to minimize the product,${\sigma}_t{\sigma}_{\omega}$, which is inversely proportional to the transmission capacity of WDM systems.

The Influence of Innovative Capacity on Regional Economic Performance (지역혁신역량이 지역경제 활성화에 미치는 영향)

  • Huh, Dongsuk
    • Journal of the Korean Geographical Society
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    • v.49 no.6
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    • pp.884-896
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    • 2014
  • This study aims to identify the factors that contribute to the regional innovative capacity and to analyze the effects on the regional economic development including newly-established corporation and job creation. The results are as follows. First, as a result of factor analysis, the 14 variables were grouped into 3 factors, i.e. innovative input, infrastructure, and linkage. Second, the panel models were developed using the above factor scores and economic performance variables such as the number of newly-established corporation and employees. As a result, innovative capacity factors positively contributed to the newlyestablished corporation and job creation. The innovative input was the most influential factor determining the regional economic performance, followed by linkage and infrastructure. This study suggests several policy implications for the reinforcement of innovative capacity and regional competitiveness.

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Modelling of System Air-Conditioner for Dynamic Simulation (동적시뮬레이션을 위한 시스템 멀티에어컨의 모델링)

  • Lee, Yoon-Jong;Kim, Chan-Jung;Moon, Je-Myung;Kim, Cheol-Woo;Seo, Hyeong-Joon;Kim, Gyoung-Rok;Shin, Haeng-Cho;Hong, Hi-Ki
    • Proceedings of the SAREK Conference
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    • 2007.11a
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    • pp.328-333
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    • 2007
  • The purpose of this study is modelling of system air-conditioner for TRNSYS. System air-conditioner is operated by a variable capacity compressor and accommodated by multiple evaporators. By reason of these feature, realizing performance of system air-conditioner for TRNSYS was incomplete. In this study performance data of system air-conditioner and control logics are used to make system air-conditioner module for TRNSYS. Performance data contains total capacity, power input and capacity index of system air-conditioner. The simulation was carried out in a mode of temperature level control using TRNSYS 16. The simulation shows that the system air-conditioner model operate variable capacity and can compute capacity index and power input of system.

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Capacity Evaluation of Multi-Carrier CDMA System in Correlated MIMO Fading Channel (상관 MIMO 페이딩 채널에서 Multi-Carrier CDMA 시스템의 용량 평가)

  • Roh, Jae Sung;Cho, Sung Joon;Kim, Choon Gil
    • Journal of Advanced Navigation Technology
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    • v.7 no.1
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    • pp.51-58
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    • 2003
  • Generally, multi-path is viewed as an undesirable feature of wireless communications. Therefore, diversity reception and adaptive array schemes are proposed to mitigate its effects. Recently, to increase the spectrum efficiency and the link reliability, multiple-input multiple-output (MIMO) scheme is devised to exploit multi-path in a scattering wireless channel. In this paper, we have evaluated the channel capacity of MIMO Multi-Carrier CDMA system in path correlation fading channel. And, the channel capacity of MIMO system is compared with single-input single-output (SISO) system. From the results, the MIMO multi-carrier CDMA system with path correlation yields better performance with respect to channel capacity than a SISO system.

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An Efficiency Evaluation of Korea's Electric Power Generation Industries using DEA model (DEA 모형을 활용한 국내 발전회사의 효율성 평가)

  • Koh, Seung-Churl;Sim, Gwang-Sic;Kim, Jae-Yun
    • Journal of the military operations research society of Korea
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    • v.34 no.1
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    • pp.61-77
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    • 2008
  • Data Envelopment Analysis(DEA) is a promising methodology to evaluate the relative efficiency of the decision-making units. We have compared the efficiency of six electric power generation companies in Korea using DEA. The analysis results by input-oriented CCR and BCC models are summarized as follows: first, different results were acquired between using input factors as total capacity of generators and as sub-totals of generator capacity based on primary energy sources. It is the result influenced by input factors which are characterized by the proportion of fixed costs(generating facilities) and variable costs(generation costs for primary energy), Second, the efficiency will be increased if the input factors selected, according to primary energy sources discussed in this research, are used during long-term expansion of electric power capacity plans. It is expected that this approach can give a feedback for management of electric power generation companies.