• Current Optics and Photonics
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• v.1 no.3
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• pp.221-227
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• 2017

To apply a square-shaped beam homogenizer to laser shock peening, it should be designed with a long working distance and by considering metal targets with various shapes and textures. For long working distances, a square-shaped beam homogenizer with a long depth of focus is required. In the range of working distance, the laser beam is required to have not only high efficiency but high uniformity, in other words, a good peening quality is guaranteed. In this study, we defined this range as the working distance for laser shock peening. We have simulated the effect of some parameters on the working distance. The parameters include the focal length of the condenser lens, pitch size of the array lens, and plasma threshold of the metal. The simulation was performed through numerical analysis by considering the diffraction effect.

• The Journal of Society for e-Business Studies
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• v.12 no.1
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• pp.73-87
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• 2007

To survive in a global competition, many companies are trying to standardize and visualize Business Process (BP) by implementing Business Process Management (BPM). Recently, enhancing business process efficiency has become one of critical success factors. In this paper, we introduce a two-phase perspective of BP efficiency: Process Engine Perspective (PEP) and Task Performer Perspective (TPP). The former is related to allocation function of BP engine; it is mainly concerned with efficient task allocation to users. The latter phase influences efficiency depending on how users execute tasks assigned to them. Instead of considering each phase separately, we develop a comprehensive method considering the two-phase together, which is more effective for the BP efficiency. We carry out simulation experiment to show the combinational effect of the two phases.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1253-1258
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• 2006

As a global effort to conservate the environment, life cycle assessment(LCA) which considers the environmental impact through the life cycle of a product, from acquiring of resources to scrapping, has been actively applied. The LCA is a tool to calculate quantitatively the environmental impacts caused by products or services through their life cycles. Eco-efficiency need that express value of environmental impact provision EMU and develops in two forms according to use target of Eco-efficiency as a tool that environmental impact of EMU. It is a strategic instrument which assists stakeholders to understand which products, processes or services to target with future investments and which are not by comparing economic and ecological values. The results stand for aggregated information on economical value and environmental impact. Also, In this method, it is important to derive EPI(Environmental Performance Index) and SPI(Service Performance Index) from the sources available. The following is used as one of Eco-efficiency tools to achieve the target performance of processes, products and services for designer or projector. According to the eco-efficiency methodology for EMU developed in this study, the user definition and the DB design were carried out as a basic design of eco-efficiency S/W.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.3
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• pp.146-154
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• 2023

Efforts have been made to reduce the greenhouse gas emissions from ships by limiting the energy efficiency index, and net zero CO₂ emission was proposed recently. The most ideal measure to achieve zero emission ship is electrification, and fuel cells are considered as a practical power source of the electrified propulsion system. The electric efficiency in the electrochemical reaction of fuel cells can be achieved up to 60% practically. The remaining energy is converted to heat energy but most of them are dissipated by cooling. In the author's previous research, a hybrid propulsion system utilizing not only electricity but also heat was introduced by combining electric motor and steam turbine. In this article, long term efficiency is evaluated for the introduced hybrid propulsion system by considering a virtual 24,000 TEU class container carrier model. To reflect a more practical operating condition, the actual navigation data of a similar real ship in the real world were collected from automatic identification system data and applied. From the result, the overall efficiency of the hybrid propulsion system is expected to be higher than a conventional electric propulsion fuel cell ship by 30%.

• Korea Trade Review
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• v.47 no.6
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• pp.135-171
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• 2022

This study is to find out how psychological characteristics and management capabilities of small manufacturers influence business performance through parameters including self-efficiency, network, and collaboration strategies. The survey was implemented between December 26, 2017 and January 15, 2018. The final 439 valid questionnaires were collected and used for analysis. The results were followed. First, the relationship between psychological characteristics and self-efficiency, and the path coefficient for psychological characteristics and network were significant. Second, management capabilities was related to self-efficiency, and the path factor for managing capability and network relationships was significant. Lastly, the path coefficients for self-efficiency and collaboration strategies were not significant, and the path coefficients for network and collaboration strategies were significant.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.9-16
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• 2020

Wireless charging has been considered an essential part of recent mobile devices. Moreover, various wireless charging systems have emerged through many studies. Among the systems, in the 2D flat coil system, the transmitter coil and receiver coil are arranged horizontally as close as possible to improve the charging efficiency. Nowadays, the 3D coil system has been proposed by adding some slope to flat 2D coils to reduce the volume. On the other hand, the 3D coil system has a lower charging efficiency than the 2D system that decreases rapidly with increasing distance. This paper proposes a new system that improves the low efficiency and charging freedom, which are the drawbacks of the existing 3D systems. The proposed system was designed in three-dimensions, and another transmitter coil was added to the transmitter coil to improve the transmission efficiency and flexibility. The measurement showed that the charging efficiency of the proposed system was 40.10% when the distance between coils was 8 mm, which is 20.5 % improvement over the existing one. The proposed method can be applied when new wireless charging systems are designed and improve charging efficiency can be improved.

• Journal of Internet Computing and Services
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• v.12 no.1
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• pp.85-98
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• 2011

Recently, the world faces a global environmental crisis by the increase of energy consumption and global warming. Since the crisis directly affects political, economic, social, and environmental areas, many countries prepare Green ICT policy to overcome it. However, although Green IT policy provides many benefits by solving environmental pollution and increasing energy efficiency, Korean government did not prepare measures by the policy. The purpose of this study is to suggest priorities of political goals for maximizing the efficiency after introducing Green ICT policy in Korea. Major variables are drawn for the analysis, and they are eco-friendliness, technology evolution, economic efficiency, energy efficiency, and stable supply of energy. The variables are suggested based on 'Low Carbon, Green Growth Act', then the survey was conducted to policy expert using AHP(Analytic Hierarchy Process) and ANP(Analytic Network Process) for prioritizing variables. As a result of the AHP, it is derived in the order of eco-friendliness, technology evolution, economic efficiency, energy efficiency, and stable supply of energy. The ANP result shows in the order of technology evolution, energy efficiency, economic efficiency, eco-friendliness, and stable supply of energy. The research is conducted to analyze the priorities of goals for Green IT policy, and the analysis results are possible to use as a practical guideline for establishing associated policies in the future.

• Ocean and Polar Research
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• v.37 no.3
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• pp.235-247
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• 2015

The main purpose of procuring the oceanographic research vessel with state-of-the-art technology is to provide a floating laboratory to conduct field work on the global oceans. The vessel should be properly utilized to locate and evaluate unexplored natural resources as well as to contribute international efforts to better understand and manage global environmental issues. Top priorities in the vessel design are high safety standards, noise and vibration control efficiency, and effective application of research equipment. For the accomplishment of all activities, the vessel length over all should be extended ~100 m with a gross tonnage of ~5,900 ton. In particular, the dynamic positioning system II will essentially operate at sea state 6. The high efficiency emissions reduction system will also be adopted in preparation for entry into force of 3rd exhaust emission control (Tier III). About 130 navigational and scientific instruments will be installed. The final design and model test of the new research vessel were reviewed and completed, respectively, in 2014. Currently, the ship is being built on schedule and expected to be delivered in December 2015. Within the near future, the new vessel will assume the role of carrying out multidisciplinary oceanographic researches of the highest standards in a technologically advanced and environment friendly manner.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.8
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• pp.761-767
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• 2011

Free and forced vibration analysis of the global ship structure using the 3-dimensional finite element(FE) method requires not only the specialized knowledge such as ship structure interacted with fluid, damping and various excitations due to propulsion system but also time-consuming manual tasks in FE modeling, analysis and response evaluation. As a result, the quality of the vibration analysis highly depends on engineer's expertise and experience. In this study, a framework system to improve the efficiency of global ship vibration analysis is introduced. The system promising the utilization of MSC/Patran and MSC/Nastran consists of various modules to support data management, FE modeling of ship structure and loading, input deck generation for free and forced vibration analysis, data extraction and evaluation of analysis results, and databases for FE models of marine diesel engines and vibration criteria. The system may be useful for pursuing standardization of uncertain analysis factors as well as reducing time, cost and human dependency in ship vibration analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.779-784
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• 2011

Free and forced vibration analysis of the global ship structure using the 3-dimensional finite element(FE) method requires not only the specialized knowledge such as ship structure interacted with fluid, damping and various excitations due to propulsion system but also time-consuming manual tasks in FE modeling, analysis and response evaluation. As a result, the quality of the vibration analysis highly depends on engineer's expertise and experience. In this study, a framework system to improve the efficiency of global ship vibration analysis is introduced. The system promising the utilization of MSC/Patran and MSC/Nastran consists of various modules to support data management, FE modeling of ship structure and loading, input deck generation for free and forced vibration analysis, data extraction and evaluation of analysis results, and databases for FE models of marine diesel engines and vibration criteria. The system may be useful for pursuing standardization of uncertain analysis factors as well as reducing time, cost and human dependency in ship vibration analysis.