• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.440-440
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• 2012

Nanomaterials have emerged as new building blocks to construct light energy harvesting assemblies. Size dependent properties provide the basis for developing new and effective systems with semiconductor nanoparticles, quantized charging effects in metal nanoparticle or their combinations in 2 and 3 dimensions for expanding the possibility of developing new strategies for photovoltaic system. As top-down approach, we developed a simple and effective method for the large scale formation of self-assembled Cu(In,Ga)$Se_2$ (CIGS) nanostructures by ion beam irradiation. The compositional changes and morphological evolution were observed as a function of the irradiation time. As the ion irradiation time increased, the nano-dots were transformed into a nano-ridge structure due to the difference in the sputtering yields and diffusion rates of each element and the competition between sputtering and diffusion processes during irradiation. As bottom-up approach, we developed the growth of CIGS nanowires using thermal-chemical vapor deposition (CVD) method. Vapor-phase synthesis is probably the most extensively explored approach to the formation of 1D nanostructures such as whiskers, nanorods, and nanowires. However, unlike binary or ternary chalcogenides, the synthesis of quaternary CIGS nanostructures is challenging because of the difficulty in controlling the stoichiometry and phase structure. We introduced a method for synthesis of the single crystalline CIGS nanowires in the form of chalcopyrite using thermal-CVD without catalyst. It was confirmed that the CIGS nanowires are epitaxially grown on a sapphire substrate, having a length ranged from 3 to 100 micrometers and a diameter from 30 to 500 nm.

• Journal of Korean Society of Transportation
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• v.35 no.1
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• pp.37-49
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• 2017

This study proposes an analysis methodology for air quality improvement effect of transport and environment policy that are used for mobile pollution sources. The methodology considers the changes of traffic of road transport sources and air pollutant emission, the changes of atmospheric dispersion of air pollutants and the effects on the health of local residents in response to policy implementation. Especially, the changes to traffic flow must be considered in evaluating the effects on atmospheric environment as it has a direct connection to the effects of the policy in this study. We used bottom-up approach (BUA) based on the travel demand model to reflect the changes of travel behavior in detail in response to the policy implementation compared to the top-down approach (TDA) when calculating the changes of emission level of road transport. We showed the applicability of the proposed analysis methodology through a policy scenario analysis, and the analysis method can be effectively applied to the cases in which travelers' behavior changes are expected.

• Review of Korean Society for Internet Information
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• v.14 no.3
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• pp.68-77
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• 2013

This article consists of 3 parts. Part I is multi stakeholder approach on Internet governance system. Part II is analysis of the Korean Internet governance system. In this part, I explain relevant laws in Korea, including Korean Internet Address Resources Act. Part III is my suggestion on Korean Internet governance system using a multi stakeholder approach. First of all, the keyword of the Internet governance system is decision making process: that is, consensus based versus top-down approach. Then who are major players in Internet governance in national level? Government, or Private sectors such as business and civil society. Korean legal system for Internet governance shows a top-down decision making process. Major players are the government (that is, Ministry of Science, ICT and Future Planning) and KISA affiliated with the government. Other players include Internet Address Policy Committee, Korea Internet Governance Alliance, and NGOs. The key statute for Internet governance in Korea is Internet Address Resources Act of 2004. Articles 3 and 5 require the Ministry of Science, ICT and Future Planning to take a proactive role in Internet governance. The government shall consult with the Internet Address Policy Deliberation Committee for Internet governance. Yet this Committee is established under the control of the Ministry of Science, ICT and Future Planning. All members of this Committee are also commissioned or nominated by the Chairman of the Ministry. Meanwhile, there are also non-official organizations, including Sub-committee on Address & Infrastructure of Korea Internet Governance Alliance. I suggest to reform decision making process of Korean Internet governance system based on BOTTOM-UP process for CONSENSUS BASED DECISION. My suggested system includes the following: (1) The government hands over a major role in Internet governance to INDEPENDENT Internet policy organization. And the government participates in such organization as ONE of the players. (2) Nomination of this committee member must be bottom-up process for a genuine multi-stakeholder model including civil society, commercial organization, end-users and experts. (3) The government should establish plan for supporting the private sector's international activity on the long-term basis.

• Journal of Digital Convergence
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• v.13 no.1
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• pp.227-235
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• 2015

Big data analysis is a means of organizational problem solving. For an effective problem solving, approaches to problem solving should take into account the factors such as characteristics of problem, types and availability of data, data analytic capability, and technical capability. In this article we propose three approaches: logical top-down, data driven bottom-up, and prototyping for overcoming undefined problem circumstances. In particular we look into the relationship of creative problem solving with the bottom-up approach. Based on the organizational data governance and data analytic capability, we also derive strategic issues concerning the sourcing of big data analysis.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.2
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• pp.52-57
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• 2011

The procedures of Continuous Descent Approach(CDA) is designed to minimize the thrust required during landing, thereby reducing fuel consumption, noise and emissions compared to conventional approach procedures. Widespread implementation of CDA would result in significant reductions in the environmental impact and aircraft operation costs. This paper estimated the possible economic effects from the perspective of airliners through cost-benefit analysis, provided that the CDA is introduced. It is now proposed that a more comprehensive analysis model, which includes the reduced ATC communication burden between controllers and pilots, not to mention the economic aspect, should be established for the improvement.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.48-48
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• 2011

We have developed a chemically-driven top-down approach using vapor phase HCl to form various GaN nanostructures and successfully demonstrated dislocation-free and strain-relaxed GaN nanostructures without etching damage formed by a selective dissociation method. Our approach overcomes many limitations encountered in previous approaches. There is no need to make a pattern, complicated process, and expensive equipment, but it produces a high-quality nanostructure over a large area at low cost. As far as we know, this is the first time that various types of high-quality GaN nanostructures, such as dot, cone, and rod, could be formed by a chemical method without the use of a mask or pattern, especially on the Ga-polar GaN. It is well known that the Ga-polar GaN is difficult to etch by the common chemical wet etching method because of the chemical stability of GaN. Our chemically driven GaN nanostructures show excellent structure and optical properties. The formed nanostructure had various facets depending on the etching conditions and showed a high crystal quality due to the removal of defects, such as dislocations. These structure properties derived excellent optical performance of the GaN nanostructure. The GaN nanostructure had increased internal and external quantum efficiency due to increased light extraction, reduced strain, and improved crystal quality. The chemically driven GaN nanostructure shows promise in applications such as efficient light-emitting diodes, field emitters, and sensors.

• Journal of Agricultural Extension & Community Development
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• v.24 no.2
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• pp.143-154
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• 2017

Saemaul Undong (SM U) initiated in Korea in the 1970's is widely acknowledged as a successful model for rural community development, despite its limitations. This paper investigates the success factors of the SMU model and the lessons thereof for Sam Sang Model of Lao PDR, which appears ineffective over the years. Results show that land reforms, social ties among villages, strong institutional support and leadership and incentive system as well as "top-down" and "bottom-up" development approaches are among the factors that significantly contributed to the success of the SMU. However, rural development program would not be effective if residents are unwilling to participate. Therefore, to successfully achieve rural community development in Lao PDR, the government should through the Sam Sang model employ top-down and bottom-up approaches to enhance local participation and address the exact needs of the local people.

• Journal of Engineering Education Research
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• v.6 no.2
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• pp.22-29
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• 2003

The ultimate goal of a hardware design course is to equip the students with the system design ability. However, the majority of the current structures of the design courses are focused on the understanding of the operational principles of each device which is used later as a building block for the design of a system. The shortcomings of this approach are, first, that it is very hard to keep the students motivated to the end of the course where system design concepts are dealt, and, second, the students do not have enough experience of the system design which is usually required in the field. As an alternative to solve these problems, it is necessary to reverse the order of contents of the course. Namely we introduce the high level of the abstract concept of the system design in the very beginning of the course and later by lowering the level of abstraction to the operational principle of the internal devices. In this paper, we propose a new top-down methodology for the introductory hardware design course of logic design, where the design expression and verification in the system-level are introduced first and then detail knowledge on each device is introduced later. Also, we report a case result from a student's working group as part of an extracurricular education in order to verify the validity of our proposed approach

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.21 no.1
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• pp.1-11
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• 2018

The emergence of mucosal healing as a treatment goal that could modify the natural course of Crohn's disease and the accumulating evidence showing that biologics are most effective in achieving mucosal healing, along with the success of early treatment regimens for rheumatoid arthritis, have led to the identification of early Crohn's disease and development of the concept of catching the therapeutic window during the early disease course. Thus, an increasing number of pediatric gastroenterologists are adopting an early biologic treatment strategy with or without an immunomodulator. Although early biologic treatment is effective, cost and overtreatment are issues that limit its early use. Currently, there are insufficient data on who will benefit most from early biologics, as well as on who will not need early or even any biologics. For now, top-down biologics should be considered for patients with currently known high-risk factors of poor outcomes. For other patients, close, objective monitoring and accelerating the step-up process by means of a treat-to-target approach seems the best way to catch the therapeutic window in early pediatric Crohn's disease. The individual benefits of immunomodulator addition during early biologic treatment should be weighed against its risks and decision on early combination treatment should be made after comprehensive discussion with each patient and guardian.

• Journal of Ocean Engineering and Technology
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• v.12 no.3 s.29
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• pp.86-95
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• 1998

CAD/CAM program developers have made substantial progress in enabling engineers to design, analyze, visualize, visualize, and simulate the performance of structures and systems. Many researchers, however, agree that there is still a way to go before the existing commercial computer software can be used in ship structural analysis to their full potential as solvers which can identify opportunities to reduce man-hours and cut costs. CAD systems used for these works in ship yards are general-purposed and not custom-tailored for ship structures, which force end-users to do tiresome and routine works. The new preprocessor "MeshGen" announced in this study can load several ship types and user-friendly generate their FE meshes employing the object-oriented approach based on the parametric and top-down design. Also "MeshGen" reduces dramatically the time required to prepare CAD models under window-based environments on desktop personal computers and makes it much easier and faster for end-users to change topology and material properties.