• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12C
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• pp.1046-1054
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• 2008

Since the high quality digital TV systems are broadly deployed in the market, the digital video contents will be edited and distributed in MPEG-2 MP@HL fonnat. Due to its impressive coding efficiency, the H.264/AVC codec has rapidly replaced the MPEG-4 SP codec for mobile digital video terminal with low quality. For the bro ad distribution of digitial video contents produced in MPEG-2 format, the MPEG-2 to H.264/AVC transcoding is highly necessary nowadays. In this paper, we propose a fast intra MB prediction mode decision method to reduce the computational complexity in the transcoding, which is the main bottleneck in the transcoders. The proposed method is based on the several relationships such as DCT coefficients and edge orientation, correlation between prediction directions in the $Intra16{\times}16$ and $Intra4{\times}4$ modes, correlation between edge-orientations of luminance an d chrominance components. The simulation results show that the proposed method can reduce the computational complexity upto 70% and 40%, compared with the cascaded transcoder and the well-known fast intraframe transc oder, respectively.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.3 s.309
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• pp.43-53
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• 2006

As wireless network technology has advanced, demands for multimedia contents through mobile environment have tendered to upward. Since network situation is changing every moment and types of user terminals are diverse, it is difficult for a content provider to consider network situation and type of user terminal to provide multimedia contents. As one solution, transcoding techniques have been proposed, but those have much complexity. In this paper, in order to reduce computational complexity, we propose a fast mode decision using input modes, motion vectors, and residual energies which are obtained from input bitstream for 2:1 down-scaling spatial transcoding application. The proposed method reduces processing time in mode decision by restricting possible mode types based on input information. Experimental results show that the proposed method achieves about 2.66 times improvement in encoding time compared to the normal encoding process while the PSNR is degraded by about 0.04dB, and bit-rate is increased by 1.6%.

• Journal of Navigation and Port Research
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• v.46 no.2
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• pp.110-120
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• 2022

Spain is Europe's second-largest country with total throughput reaching 16.7 million twenty-foot equivalent units (TEU) by 2020. The purpose of this study was to measure and compare the efficiency of 17 container terminals. As a study method, the DEA-CCR model, undesirable variable, and Malmquist Index (MI) were used for data envelopment analysis (DEA). The study results are as follow: (1) DEA-CCR is used to evaluate basic efficiency. The most efficient terminals are decision-making units DMU 1 (APM Terminals (Algeciras Port)), DMU 2 (Total Terminal International Algeciras (Algeciras Port)) and DMU 5 (Barcelona Europe South Terminal (Barcelona Port)). (2) Undesirable DEA was conducted to suggest inefficiency from the undesirable output. Overall, the efficiency scores were reduced. However, DMU 1, DMU 2, and DMU 5 maintained efficiency scores regardless of the finish factor. (3) Malmquist Index was used to observe technology and efficiency changes dynamically. The changes in TCI affected Spanish container terminals more than the Technical Efficiency Change Index (TECI) in 2018-2019. However, in 2019-2020, the TECI was 2.706, higher than the TCI value, indicating that the change in TECI had more influence on the increase in productivity. This study offers a broader understanding of Spanish container terminals.

• Journal of Korea Port Economic Association
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• v.27 no.1
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• pp.95-109
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• 2011

The aim of this study is to analyze the container terminal operation by considering the key factors that fluctuates the container traffic volume using the System Dynamics (SD) method. The target area of this study is the 'A' container terminal which is located in the Port of Incheon and the simulation period is from 2004 to 2020. As evaluation indexes for container terminal operation, three factors such as 'total sales', 'operating ratio of C/Y' and 'operating ratio of G/C' are selected, and as for the key factors of fluctuating container traffic volume, 'variation ratio of world trade', 'variation ratio of trade among three countries in North-East Asia' and 'variation ratio of won-dollar rate are used. As of 2020, the result of this study is that import-export container traffic volume increases almost 880,000TEU and total sales and operating ratio of G/C each reach 7.1 bilion won and 65 percent. No changes however in loadage and operating ratio of C/Y in 'A' container terminal are indicated. The reason is that capability of C/Y is exceeded. Therefore this study suggest that decision-makers of 'A' container terminal realize the importance of additional space of C/Y.

• Journal of Navigation and Port Research
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• v.31 no.5 s.121
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• pp.361-368
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• 2007

The storage space requirement is a very important decision variable which determines the storage capacity of a container terminal. Generally, the storage space requirement is dependent upon such factors as ship headway, allowable dwell time of containers, loading/winding time per ship, and so on. Until now, the storage space requirement is estimated under the assumption that the factors are deterministic in several studies. However, this study proposes how to estimate a storage space requirement satisfying the required service level under the assumption that a containership's load size is probabilistic. Numerical experiments, which use a simulation show that the proposed method can estimate more adequately the storage space requirement than other methods under a probabilistic environment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.1
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• pp.65-69
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• 2020

The aim of this study is to improve the fault decision ability of FRTU (Feeder remote terminal unit) in DAS (Distribution automation system). FRTU uses the FI (Fault indicator) algorithm based on fault current pickup and operation of the protection device. Even if the inrush current flows or the protection device is sensitive to the transient current, FRTU may indicate incorrect fault information. To address these problems, we propose an improved fault recognition algorithm that can be applied to FRTU. We will detect a specific wave that is indicative of a fault, and use this information to identify a fault wave. The specific wave-detection algorithm is based on the duration and periodicity of the voltage, current, and harmonic variations. In addition, we propose fault recognition algorithms using voltage factor variation analysis and DWT (Discrete wavelet transform). All the wave data used in this study were actual data stored in FRTU.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.330-333
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• 2003

Initial cluster size for clustering of partitioning methods is very important to the clustering result. In K-means algorithm, the result of cluster analysis becomes different with optimal cluster size K. Usually, the initial cluster size is determined by prior and subjective information. Sometimes this may not be optimal. Now, more objective method is needed to solve this problem. In our research, we propose a hybrid genetic algorithm, a tree induction based evolution algorithm, for determination of optimal cluster size. Initial population of this algorithm is determined by the number of terminal nodes of tree induction. From the initial population based on decision tree, our optimal cluster size is generated. The fitness function of ours is defined an inverse of dissimilarity measure. And the bagging approach is used for saying computational time cost.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.76-79
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• 2009

Recently there has been much effort, in both academia and industry, to integrate a plethora of wireless technologies in order to provide seamless connection to mobile users. To support seamless connection on terminal needs fast handover function and location management function. Especially, Performing fast handover has to interact with function of datalink layer and mobility based IP. In this paper, we propose a handover decision mechanism using MIH( Media Independent Handover) in hybrid networks to reduce the delay of transmission for data.

• Food Science and Industry
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• v.51 no.1
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• pp.61-71
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• 2018

The evaluation of food taste is one of the important activities of human consciousness and it is practiced by sensory analysis using 5 terminal sensorial consciousness among many other functions. These consciousness activities may be conducted by 3 way branching transformation (3-WBT) logic, which choose one out of 3 options under the multi-layered consciousness decision making system. On the basis of this logic, cognitive sensory evaluation (CSE) method was developed to carry out questionnaire survey covering objective and subjective issues during consumption of food for pregnant women. The results of the CSE for several food items was presented with the Table-pattern called CSET covering consciousness factors and their effects on the food consumers.

• Journal of the Korea Society of Computer and Information
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• v.11 no.3
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• pp.1-10
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• 2006

It is widely accepted that the coverage with high user densities can only be achieved with small cell such as micro- and pico-cell. The smaller cell size causes frequent handovers between cells and a decrease in the permissible handover Processing delay. This may result in the handover failure. in addition to the loss of some Packets during the handover. In these cases. re-transmission is needed in order to compensate errors, which triggers a rapid degradation of throughput. In this paper, we propose a new handover scheme in the next generation mobile communication systems, in which the handover setup process is done in advance before a handover request by predicting the handover cell based on mobile terminal's current position and moving direction. Simulation is focused on the handover failure rate and Packet loss rate. The simulation results show that our proposed method provides a better performance than the conventional method.