• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.1
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• pp.44-57
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• 2016

Rectification is used as a preprocessing to reduce the computation complexity of disparity estimation. However, rectification also requires a complex computation. To minimize the computing complexity, rectification using a lookup-table (R-LUT) has been introduced. However, since, the R-LUT consumes large amount of memory, rectification with compressed LUT (R-CLUT) has been introduced. However, the more we reduce the memory consumption, the more we need decoding overhead. Therefore, we need to attain an acceptable trade-off between the size of LUT and decoding overhead. In this paper, we present such a trade-off by adaptively combining simple coding methods, such as differential coding, modified run-length coding (MRLE), and Huffman coding. Differential coding is applied to transform coordinate data into a differential form in order to further improve the coding efficiency along with Huffman coding for better stability and MRLE for better performance. Our experimental results verified that our coding scheme yields high performance with maintaining robustness. Our method showed about ranging from 1 % to 16 % lower average inverse of compression ratio than the existing methods. Moreover, we maintained low latency with tolerable hardware overhead for real-time implementation.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.2
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• pp.58-63
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• 2002

One of the important problems of OFDM system is the large PAPR of the output signal, which can result the significant signal distortion in presence of nonlinear amplifiers. To reduce the PAPR, we use fundamentally the level clipping and propose the modified mapping/demapping method for effective reducing the PAPR of the OFDM signals with level clipping. We can significantly improve the BER performance characteristics for the OFDM system. We discussed, through extensive computer simulations, the effects of level clipping and modified mapping/demapping method on the performance of OFDM system including the trade off between bandwidth expansion and BER performance and between bandwidth efficiency and BER performance.

• International Journal of Naval Architecture and Ocean Engineering
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• v.2 no.2
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• pp.104-111
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• 2010

The complete avoidance of cavitation, as a result of gap flow between the fixed and movable portion of a horn type rudder system, is difficult. To reduce gap flow, it is a common practice to attach a half round prismatic bar that protrudes beyond the concave surface of the horn facing the gap and laid along the centerplane of the rudder. However the employment of such a device does not always yield satisfactory results. Previously, the authors have shown that a pair of blocking bars, attached on the convex surface of the movable portion, better enhance the blocking ability of gap flow to that of a single centre bar installed on the concave surface. This also circumvents difficulties that might occur in practical applications. In the present study, a series of numerical computations show that flow injected into the gap of a rudder may also block the flow within, without employment of any physical devices, such as a half circular bar. This study also shows that the combination of flow injection and blocking bars may result in the synergic augmentation of blocking efficiency of gap flow, as demonstrated in computations for a three dimensional rudder system.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.5
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• pp.415-420
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• 2018

The development of sail gas has increased the production of ethane as well as natural gas. The decline in the market price for ethane has led to a change in the petroleum-based ethylene production process into an ethane-based ethylene production process and an increase in the ethane/ethylene trade volume. Large-scale ethane/ethylene carrier have been needed due to an increase in long-distance trade from the US, and cargo type change have leaded to consider a liquefaction process to re-liquefy Boil-Off gas generated during the voyage. In this paper, the liquefaction system of Liquefied Ethane Gas carrier was evaluated with Low-GWP (Low-Global Warming Potential) refrigerant and process parameters, Boil-Off Gas pressure and expansion valve outlet pressure, were optimized. Low-GWP refrigerants were propane (R290), propylene(R1270), carbon dioxide(R744) was considered at two type of liquefaction process such as Linde and cascade cycle. The results show that the optimal pressure point depends on the individual refrigerant and the highest liquefaction efficiency of carbon dioxide (R744) - propane (R290) refrigerant.

• Journal of Communications and Networks
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• v.18 no.4
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• pp.580-588
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• 2016

Energy efficiency is the main objective in the design of a wireless sensor network (WSN). In many applications, sensing data must be transmitted from sources to a sink in a timely manner. This paper describes an investigation of the trade-off between two objectives in WSN design: minimizing energy consumption and minimizing end-to-end delay. We first propose a new distributed clustering approach to determining the best clusterhead for each cluster by considering both energy consumption and end-to-end delay requirements. Next, we propose a new energy-cost function and a new end-to-end delay function for use in an inter-cluster routing algorithm. We present a multi-hop routing algorithm for use in disseminating sensing data from clusterheads to a sink at the minimum energy cost subject to an end-to-end delay constraint. The results of a simulation are consistent with our theoretical analysis results and show that our proposed performs much better than similar protocols in terms of energy consumption and end-to-end delay.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.50-54
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• 2010

A Container Security Device (CSD) which is different existing RFID Tag strengthens the physical security as mounted inside the container and the information security as encrypts doubly a data. CSD must use the resources efficiently in order to operate with the battery. Therefore, it needs low-power mechanism which repeats the sleep period and channel scan period. However, by adjusting these periods, the trade-off occurs between energy efficiency and network connectivity. In this paper, we implement low-power CSD and resolve this problem by adjusting beacon period and channel scan time. As a result, We guarantee the network connectivity 95% or more and maximum life up to 16 days using common AA batteries.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.153-154
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• 2019

본 논문에서는 사물인터넷(Internet of Things, IoT)에 적용되어 사용될 수 있는 다중 게이트웨이 환경에서 각 게이트웨이의 자원 상황에 따라 종단 노드를 클라우드 단으로 직접 트레이드하여 처리함으로서 게이트웨이의 자원 소모를 줄이고 높은 처리량을 요구하는 종단 노드를 빠르게 처리 가능한 기법을 제안한다. 본 논문에서는 해당 기법의 효율성 입증을 위하여 클라우드 컴퓨팅이라는 대규모 환경을 가정하여 실험을 진행하였으며, 해당 실험의 결과에 따르면 높은 처리량을 요구하는 종단 노드를 클라우드 단에 트레이드하여 직접 처리함으로서 클라우드 단 하부의 다중 게이트웨이의 자원 소모율 감소 및 데이터 처리 속도가 증대 되었음을 확인할 수 있다.

• Korea Trade Review
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• v.44 no.6
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• pp.345-361
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• 2019

In recent years, Chinese firms have explosively increased outward foreign direct investment (oFDI). While state-owned enterprises (SOEs) are still dominant in Chinese oFDI, privately-owned enterprises (POEs) are also accelerating their internationalization. These two types of Chinese firms differ in their behavior regarding oFDI. The objective of this paper is to analyze the differences in the choice of oFDI locations between Chinese SOEs and POEs by considering host country factors. By integrating the literature on Chinese firms' oFDI and on FDI locations, we developed six hypotheses concerning how host country factors affect their choice of location. We tested our hypotheses by conducting multiple regression analysis with recent secondary data on 413 Chinese MNEs in 88 countries between 2005 and 2016. The results of the test show that in selecting oFDI locations, Chinese SOEs invest relatively more in countries with richer natural resources, more abundant strategic assets, less production efficiency, higher political risk, and lower institutional quality compared with Chinese POEs. It is our hope that the empirical results of this paper will contribute to research on Chinese oFDI.

• Korea Trade Review
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• v.44 no.3
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• pp.25-42
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• 2019

This research examined the mediation effect of Workforce Agility (WA) on the relationship between environmental uncertainty and operational performance. We manipulated the control variables that are known to be affected by employment flexibility. Employment flexibility is caused by idiosyncratic characteristics of Korean port system. The analysis was tested by Baron & Kenny's method. The result indicates that each path of the proposed model is significant. Furthermore, the mediation effect was checked with the Sobel Test. The research revealed that environment uncertainty poses an indirect effect on operational performance. Both supply/demand uncertainty and technological uncertainty affected operational performance through the mediation effect of WA. Most of the distribution centers located in Busan Newport Distripark are operated in a bimodal labor (human resource) system which includes both permanent employees (workers) and temporary employees (workers). This empirical research provides theoretical and managerial implications by suggesting ways to increase efficiency in distribution center operation through WA enhancement, and to improve the unloading labor system.

• Korea Trade Review
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• v.43 no.1
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• pp.25-45
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• 2018

International commercial arbitration is an inseparable part of today's international commerce. International transactions are becoming increasingly complex. Problems brought by multi-party and multi-contract arbitration pose problems for traditional arbitration systems. The Korean Commercial Arbitration Board(KCAB) has released updated International Arbitration Rules(2016 Rules) and has adopted innovations similar to those introduced in the rules of major international arbitration institutions in recent years. The changes in the 2016 Rules are intended to increase the efficiency of the arbitral process, and introduce the process for consolidation of claims. For international commerce contracts, it would be appropriate, and necessary, to adopt a multi-party arbitration clause, as consolidated arbitration provides effective resolutions for multi-party disputes.