• International journal of advanced smart convergence
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• v.9 no.3
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• pp.49-58
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• 2020

Non-orthogonal multiple access (NOMA) has been recognized as a significant technology in the fifth generation (5G) and beyond mobile communication, which encompasses the advanced smart convergence of the artificial intelligence (AI) and the internet of things (IoT). In NOMA, since the channel resources are shared by many users, it is essential to establish the user fairness. Such fairness is achieved by the power allocation among the users, and in turn, the less power is allocated to the stronger channel users. Especially, the first and second strong channel users have to share the extremely small amount of power. In this paper, we consider the power optimization for the two users with the small power. First, the closed-form expression for the power allocation is derived and then the results are validated by the numerical results. Furthermore, with the derived analytical expression, for the various channel environments, the optimal power allocation is investigated and the impact of the channel gain difference on the power allocation is analyzed.

• Journal of Information Technology Applications and Management
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• v.23 no.2
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• pp.239-261
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• 2016

Wide use of smart and high performing mobile device makes consumers use diverse distribution channels, composed of online and offline channel. Smart companies are trying to deploy omni channel. In order to successfully integrate these diverse channels, it is necessary to understand consumers' preference of channel choice. Thus, this study was focused on the influencing factors of channel preference such as price sensitivity, consumer innovativeness, time pressure, and need-for-touch. And this study compared these influencing factors between Korea and China, and drew meaningful message for e-commerce companies and offline distribution companies.

• Transactions of Materials Processing
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• v.14 no.3 s.75
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• pp.263-268
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• 2005

Heating channel layout design and evaluation technology for SMC molding system was investigated in this work. Traditional rules of cooling channel design in injection molding were applied to the present work. Finite element thermal analysis with $ANSYS^{TM}$ was performed to evaluate the temperature distribution of SHC mold surface. SMC mold was manufactured to evaluate the effect of a proposed heating channel layout system on the temperature distribution of SMC mold surface and infrared camera was applied to a measurement of temperature distribution. It was shown that infrared camera application was possible in a measurement of temperature distribution on SHC mold surface.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.4
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• pp.302-310
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• 2008

This paper puts forward an advanced consideration on the design of scaled multiple-gate FET (MuGFET); the aspect ratio ($R_{h/w}$) of the fin height (h) to fin width (w) of MuGFET is considered with the aid of 3-D device simulations. Since any change in the aspect ratio must consider the trade-off between drivability and short-channel effects, it is shown that optimization of the aspect ratio is essential in designing MuGFET's. It is clearly seen that the triple-gate (TG) FET is superior to the conventional FinFET from the viewpoints of drivability and short-channel effects as was to be expected. It can be concluded that the guideline of w < L/3, where L is the channel length, is essential to suppress the short-channel effects of TG-FET.

• Journal of Communications and Networks
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• v.14 no.3
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• pp.237-242
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• 2012

One of the major problems for accurate channel estimation in power line communication systems is impulsive noise. Traditional channel estimation algorithms are based on the assumption of Gaussian noise, or the need to locate the positions of impulsive noise. The algorithms may lose optimality when impulsive noise exists in the channel, or if the location estimation of impulsive noise is inaccurate. In the present paper, an effective channel estimation algorithm based on a robust cost function is proposed to mitigate impulsive noise. The proposed method can provide a closed-form solution, and the application of robust estimation theory enables the proposed method to be free from localization of impulsive noise and thus can guarantee that the proposed method has better performance. Simulations verified the proposed algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.3
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• pp.855-868
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• 2012

In this paper, we consider the discrete memoryless user relaying channel (DMURC) in which a user-relay switches its operational mode symbol-by-symbol. In particular, we obtain upper and lower bounds on the channel capacity for the general DMURC and then show that these the upper and lower bounds coincide for degraded DMURC. It is also shown that the capacity of the degraded DMURC can be achieved using two separate codebooks corresponding to the two UR states. While the UR is assumed to switch states symbol-by-symbol, the results in this paper is the same as when the UR switches states packet-by-packet.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.5
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• pp.1588-1603
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• 2014

In space diversity combining, conventional methods such as maximal ratio combining (MRC), equal gain combining (EGC) and selection combining (SC) are commonly used to improve the output signal-to-noise ratio (SNR) provided that the channel is perfectly estimated at the receiver. However, in practice, channel estimation is often imperfect and this indeed deteriorates the system performance. In this paper, diversity combining techniques based on two evolutionary algorithms, namely genetic algorithm (GA) and particle swarm optimization (PSO) are proposed and compared. Numerical results indicate that the proposed methods outperform the conventional MRC, EGC and SC methods when the channel estimation is imperfect while it shows similar performance as that of MRC when the channel is perfectly estimated.

• Journal of the Korean Society of Marine Environment & Safety
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• v.3 no.1
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• pp.15-31
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• 1997

This work aims at examining the navigational safety of the entrance channels of Masan harbour and suggesting the way to improve ships' navigational safety through the channels. It has been found, from the on-scene investigation of the navigational safety at Masan, that the depth of the Budo-Sudo channel is not deep enough to cater for the largest vessel visiting the harbour, and that the No.2 navigational channel is not wide enough for the vessel. An additional new waterway, therefore, has been recommended to be established in the south of the Budo-Sudo channel so that the deep draft vessel can detour. The No.2 navigational channel has been recommended to be widen. The width of the channel was suggested to be 280 meters. A waterway design simulation methodology has been applied to examine the safety of the newly suggested channels. New channels have been proved to be safe from the experiment.

• Journal of Ship and Ocean Technology
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• v.4 no.2
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• pp.24-37
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• 2000

The purpose of this paper is to study the upstream waves in front of an advancing arbitrary hull shape in a restricted water channel. Conventionally, in a restricted water channel, shallow water effects are amplified because of the finite water depth and width. When the effects of shallow water and the restricted channel width are severe, upstream waves propagate forward from the fore-body of the advancing hull. In this study, numerical simulations are carried out for the relevant analysis of the flow phenomena by the draft variation of advancing hull in a restricted water channel. Numerical simulations are done with a finite-difference method based on the MAC scheme in a rectangular grid system.

• Transactions on Electrical and Electronic Materials
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• v.7 no.3
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• pp.99-102
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• 2006

The electrical characteristics of CMOS inverter with LDMOSFET are studied for high power and digital circuit application by using two dimensional MEDICI simulator. The simulation is done in terms of voltage transfer characteristic and on-off switching properties of CMOS inverter with variation of channel length and channel doping levels. The channel which surrounds a junction-type source in LDMOSFET is considered to be an important parameter to decide a circuit operation of CMOS inverter. The digital logic levels of input voltage show to increase with increase of n-channel length and doping levels while the logic output levels show to the almost constant.