• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.4
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• pp.1008-1018
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• 1996

For assigning channel in a cellular sireless network, we purpose satisfying constraints with a related probability between cells and channels on the channel interference matrix formed by m terminals and n channels. And we purpose to get efficient channel assigning to limited channels in a wireless cell using parallelism of neural networks. In this paper, we solve the problem according to the number of requeirements when channel change with 11-533 procession elements. We demonstrate efficiency of proposed algorithm through same simulations in a specific time period.

• The Journal of Fisheries Business Administration
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• v.46 no.3
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• pp.143-161
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• 2015

This study presents a comparative analysis on mackerel distribution process and price formation process, and investigation of price and margin between traditional markets and Large-scale discount store distribution channel. Through this, the study investigated distribution efficiency of each channel, and examined whether a difference of distribution efficiency leads to a difference of performance through the investigation of a difference of function and role between members of a wholesale market and vendor of Large scale discount store. The following are the results of this study. As a consequence of investigating supply and sum by distribution channel of mackerel, it appeared that mackerels shipped from port market are distributed into 9 consumption sites(Wholesale market, Large scale discount store, Institutional Food Service, etc.). In the comparison of distribution efficiency between traditional retail store and Large scale discount store 52.0% margin is formed in traditional retail store distribution channel and 43.1% margin is formed in Large scale discount store, and a distribution cost rate consists of 19.4% cost in a traditional retail store for fishery products and 18.1% cost in a Large-scale discount store. To analyze a difference of performance, the study examine a difference of role and function between vendor and Wholesale market company, wholesaler and middleman. Wholesale market company and middleman of wholesale market for consumer have slightly high or similar score in collection function, sorting function, evaluation function and financial function which are traditional and original. However, it was confirmed that vendor has a better score in other functions, that is, newly-demanded functions(ex : market frontier function, product development function, Integral Distribution Function, etc.).

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.36 no.4
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• pp.138-148
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• 2024

Multi-resonance wave energy converter can generate efficient power generation by complexly utilizing the resonance phenomenon of waves even when waves propagate normally. As the wave is amplified by resonance, the power generation efficiency of the multi-resonance wave energy converter increases, and the shape of the resonance part needs to be optimized to maximize power generation efficiency. The multi-resonance wave energy converter amplifies waves in the seiche resonance part and the channel resonance part. In this study, CFD numerical experiments were performed under various conditions such as the length and location of the channel resonance part to analyze the sensitivity for each condition and derve the optimal shape of the channel resonance part.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.395-398
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• 2001

Studies on quantity discounts have been in two directions since Buchanen[1] published that suppliers provide quantity discounts for price discrimination and for channel efficiency. The quantity discounts for price discrimination have been treated in economics. On the contrary, the quantity discounts for channel efficiency have been studied in production management with assumptions and focuses different from economics. In this paper, the differences in each area are analyzed and purchasing situations that supplier's motivation on quantity discounts occurs is analyzed and the purchasing situations for two-stage quantity discounts are specified. In conclusion, we suggest that suppliers can enhance channel coordination through two stage quantity discounts in these purchasing situations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.2 no.4
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• pp.209-221
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• 2008

In this paper, we propose a subcarrier allocation method and a composite linear minimum mean square error (LMMSE) channel estimator to increase spectrum efficiency in orthogonal frequency division multiplexing (OFDM) transmit diversity. The pilot symbols for OFDM transmit (Alamouti) diversity are exclusively allocated in two OFDM symbols in different antennas, which causes serious degradation of spectrum efficiency. To reduce the number of pilot symbols, our subcarrier allocation method uses repetition-coded data symbols, and the proposed channel estimator maintains good bit error rate (BER) performance.

• Journal of information and communication convergence engineering
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• v.14 no.4
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• pp.227-232
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• 2016

In this study, the performance of a 32-quadrature amplitude position modulation (QAPM) system is analyzed under a Rician fading channel condition when the maximal ratio combining (MRC) diversity technique is used in the receiver. The fading channel is modeled as a frequency non-selective slow Rician fading channel corrupted by additive white Gaussian noise (AWGN). QAPM is available to improve BER performance without amplifying transmit power, and MRC diversity makes the performance improvement of QAPM system even bigger by intentionally maximizing SNR. Error performances are shown for the 32-QAPM system and a 32-phase silence shift keying (PSSK) system in order to examine the effects of fading severity, for various values of the Rician parameter, K. The dependence of error rates on MRC diversity is also analyzed. The simulation results show that the BER performance of the 32-QAPM system is better than that of the 32-PSSK system under the above mentioned conditions.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.4
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• pp.379-389
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• 2002

In this paper, we study the competition between two kinds of suppliers, a bricks and mortars(B&M) and a clicks and mortars(C&M). Using the circular spatial market model, we derive and analyze the Nash and Stackelberg equilibria as a function of offline market share and efficiency of online channel of the C&M supplier. The result can be summarized as follows: (1) Stackelberg equilibrium is always superior to the Nash equilibrium, (2) Under certain conditions, the price of online channel can be higher than that of offline channel, (3) It is impossible for the C&M supplier to encroach on all of the B&M supplier's market, (4) In some cases, the C&M supplier has incentive to lower the efficiency of its online channel for more profit.

• Journal of Power Electronics
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• v.15 no.2
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• pp.319-326
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• 2015

In this paper, a cost-effective single switch multi-channel LED (light emitting diode) driver is proposed. While conventional LED drivers require as many non-isolated DC/DC converters as the number of LED channels, the proposed LED driver needs only one power switch and several balancing capacitors instead of expensive non-isolated DC/DC converters. Therefore, the proposed driver features a simpler structure, with a lower cost and a higher efficiency. Because its power switch can be turned off under the zero current switching condition, it has very desirable advantages such as improved electromagnetic interference characteristics and high efficiency. Moreover, it uses only a small number of DC blocking capacitors with no additional active devices for the current balancing of multi-channel LEDs. As a result, the proposed driver exhibits high reliability and is cost effective. To confirm the validity of the proposed driver, a theoretical analysis is performed, and design considerations and experimental results obtained from a prototype that is applicable to a 46" LED-TV are presented.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.275-281
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• 2005

In this work, Scalar Passive code in Lattice Boltzmann Method was employed to simulate mixing performance of Passive mixer in a micro-channel. It physically analyzed stream line and Pressure drop for passive mixer in a micro-channel. The flow characteristics in a micro-channel was a function of Peclet number. The results indicated that the size of static element was more effect on the mixing than the number of static element and the distance of static elements.

• ETRI Journal
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• v.45 no.4
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• pp.557-569
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• 2023

Traditional deterministic channel modeling is accurate in prediction, but due to its complexity, improving computational efficiency remains a challenge. In an alternative approach, we investigated a multilayer artificial neural network (ANN) to predict large-scale and small-scale channel characteristics in metro tunnels. Simulated high-precision training datasets were obtained by combining measurement campaign with a ray tracing (RT) method in a metro tunnel. Performance on the training data was used to determine the number of hidden layers and neurons of the multilayer ANN. The proposed multilayer ANN performed efficiently (10 s for training; 0.19 ms for prediction), and accurately, with better approximation of the RT data than the single-layer ANN. The root mean square errors (RMSE) of path loss (2.82 dB), root mean square delay spread (0.61 ns), azimuth angle spread (3.06°), and elevation angle spread (1.22°) were impressive. These results demonstrate the superior computing efficiency and model complexity of ANNs.