• 대한수학회지
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• 제42권2호
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• pp.223-241
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• 2005

Inequalities on the rank of the sum and the product of two matrices over semirings are surveyed. Preferences are given to the factor rank, row and column ranks, term rank, and zero-term rank of matrices over antinegative semirings.

• 한국경영과학회지
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• 제6권1호
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• pp.71-74
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• 1981

The purpose is to discuss the relationship between zero-sum two-person game with vector-payoff and multiple objective linear program. Further this paper shows that game against nature with vector payoff can be reduced to linear program.

• 호남수학학술지
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• 제44권4호
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• pp.618-627
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• 2022

On the setting of the orthogonal complement of the weighted Bergman space, we study the problem of when a finite sum of dual Toeplitz products is compact or zero. Our results extend several known results on the unweighted space to the weighted spaces.

• 대한수학회보
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• 제60권1호
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• pp.161-170
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• 2023

We consider dual Toeplitz operators acting on the orthogonal complement of the Dirichlet space on the unit disk. We give a characterization of when a finite sum of products of two dual Toeplitz operators is equal to 0. Our result extends several known results by using a unified way.

• Communications for Statistical Applications and Methods
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• 제19권4호
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• pp.559-569
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• 2012

Compositional data consist of compositions that are non-negative vectors of proportions with the unit-sum constraint. In disciplines such as petrology and archaeometry, it is fundamental to statistically analyze this type of data. Aitchison (1983) introduced a log-contrast principal component analysis that involves logratio transformed data, as a dimension-reduction technique to understand and interpret the structure of compositional data. However, the analysis is not usable when zero values are present in the data. In this paper, we introduce 4 possible methods to reduce the dimension of compositional data with zero values. Two real data sets are analyzed using the methods and the obtained results are compared.

• 대한수학회보
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• 제51권1호
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• pp.77-82
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• 2014

We prove that if ${\mid}a_1{\mid}$ is large and ${\mid}a_0{\mid}$ is small enough, then every approximate zero of power series equation ${\sum}^{\infty}_{n=0}a_nx^n$=0 can be approximated by a true zero within a good error bound. Further, we obtain Hyers-Ulam stability of zeros of the polynomial equation of degree n, $a_nz^n$ + $a_{n-1}z^{n-1}$ + ${\cdots}$ + $a_1z$ + $a_0$ = 0 for a given integer n > 1.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권7호
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• pp.2371-2388
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• 2015

In this paper, we investigate the performance evaluation of three dimensional (3D) multiple-input multiple-output (MIMO) systems with an adjustable base station (BS) antenna tilt angle and zero-forcing (ZF) receivers in Ricean/Lognormal fading channels. In particular, we take the lognormal shadow fading, 3D antenna gain with antenna tilt angle and path-loss into account. First, we derive a closed-form lower bound on the sum rate, then we obtain the optimal BS antenna tilt angle based on the derived lower bound, and finally we present linear approximations for the sum rate in high and low-SNR regimes, respectively. Based on our analytical results, we gain valuable insights into the impact of key system parameters, such as the BS antenna tilt angle, the Ricean K-factor and the radius of cell, on the sum rate performance of 3D MIMO with ZF receivers.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.400-402
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• 2000

This paper presents a game theoretic approach for power transactions analysis in a competitive market. The considered competitive power market is regarded as PooICo model, and the participating players are restricted by only two generating entities for simplicity in this paper. The analysis is performed on the basis of marginal cost based relations of bidding price and bidding generations. That is, we assume that the bidding price of each player is determined by the marginal cost when the bidding generation is pre-determined. This paper models the power transaction as a two player game and analyzes by applying the Nash eauilibrium idea. The generalized game model for power transactions covering constant-sum(especially zero-sum), and nonconstant-sum game is developed in this paper. Also, the analysis for each game model are performed in the case studies. Here, we have defined the payoff of each player as the weighted sum of both player's profits.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1344-1346
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• 1999

This paper presents a game theoretic approach for power transactions analysis in a competitive market. The considered competitive power market is regarded as PoolCO model, and the participating players are restricted by only two generating entities for simplicity in this paper. The analysis is performed on the basis of marginal cost based relations of bidding price and bidding generations. That is, we assume that the bidding price of each player is determined by the marginal cost when the bidding generation is pre-determined. This paper models the power transaction as a two player game and analyzes by applying the Nash eauilibrium idea. The generalized game model for power transactions covering constant-sum(especially zero-sum), and nonconstant-sum game is developed in this paper. Also, the analysis for each game model are Performed in the case studies. Here, we have defined the payoff of each player as the weighted sum of both player's profits.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권3호
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• pp.1098-1112
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• 2018

Achievable sum rate and energy efficiency (EE) are investigated for the massive multiple-input multiple-output (Massive MIMO) downlink with channel aging in the time varying Ricean fading channel. Specifically, the expression of the achievable sum rate of the system for the maximum ratio transmission (MRT) precoder with aged channel state information (CSI) in the time varying Ricean fading channel is first presented. Based on the expression, the effect of both channel aging and the Ricean factor on the power scaling law are studied. It is found that the transmit power of base station (BS) is scaled down by $1/{\sqrt{M}}$(where M is the number of the BS antennas) when the Ricean factor K is equal to zero (i.e., time varying Rayleigh fading channel), indicating that aged CSI does not affect the power scaling law. However, the transmit power of the BS is scaled down by 1/M for the time varying Ricean fading channel (where $K{\neq}0$) indicating that the Ricean factor affects the power scaling law and sum rate, and channel aging only leads to a reduction of the sum rate. Second, the EE of the system is analyzed based on the general power consumption model. Both the theoretical analysis and the simulations show that the channel aging could degrade the sum rate and the EE of the system, and it does not affect the power scaling law.