• Current Photovoltaic Research
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• v.3 no.3
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• pp.97-100
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• 2015

The kesterite $Cu_2ZnSnSe_4$ (CZTSe) thin film solar cells were synthesized by selenization of sputtered Cu/Sn/Zn metallic precursors on Mo coated soda lime glass substrate in Ar atmosphere. Cu/Sn/Zn metallic precursors were deposited by DC magnetron sputtering process with 30 W power at room temperature. As-deposited metallic precursors were placed in a graphite box with Se pellets and selenized using rapid thermal processing furnace at various temperature ($480^{\circ}C{\sim}560^{\circ}C$) without using a toxic $H_2Se$ gas. Effects of Selenization temperature on the morphological, crystallinity, electrical properties and cell efficiency were investigated by field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD), J-V measurement system and solar simulator. Further details about effects of selenization temperature on CZTSe thin films will be discussed.

• Korean Journal of Materials Research
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• v.18 no.2
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• pp.61-64
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• 2008

Electrical optical switching and structural transformation of $Ge_{15}Sb_{85}$, $Sb_{65}Se_{35}$ and N2.0 sccm doped $Sb_{83}Si_{17}$ were studied to investigate the phase change characteristics for PRAM application. Sb-based materials were deposited by a RF magnetron co-sputtering system and the phase change characteristics were analyzed using an X-ray diffractometer (XRD), a static tester and a four-point probe. Doping Ge, Se or Si atoms reinforced the amorphous stability of the Sb-based materials, which affected the switching characteristics. The crystallization temperature of the Sb-based materials increased as the concentration of the Ge, Se or Si increased. The minimum time of $Ge_{15}Sb_{85}$, $Sb_{65}Se_{35}$ and N2.0 sccm doped $Sb_{83}Si_{17}$ for crystallization was 120, 50 and 90 ns at 12 mW, respectively. $Sb_{65}Se_{35}$ was crystallized at $170^{\circ}C$. In addition, the difference in the sheet resistances between amorphous and crystalline states was higher than $10^4{\Omega}/{\gamma}$.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1904-1911
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• 2010

LRT projects pursue fully automated manless operating system with an aim to achieve a minimum availability of 99%. System performance is required to be guaranteed by verified SE procedures to meet user requirements for maintaining system availability above 99%. Configuration Management is one of the most practical SE application methods that manage various changes that may have a major influence on system performance on the process of undertaking assigned projects and find out problems in the system through future tracking systems. This paper discusses further use of Configuration Management in the areas concerned after examining the cases that apply Configuration Management, one of SE application methods, to the ongoing local LRT projects.

• Journal of the Korean Society of Systems Engineering
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• v.7 no.1
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• pp.43-51
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• 2011

SE generally defines approaching ways of conducting identification, verification and integration of an optimized product and process solution to meet customer's needs by leveraging organizational competency in engineering and management. To successfully develop a new product under mass production contract, it is important to efficiently carry out the program by ensuring that three major competencies are secured; core technology, system integration, and program management. For successful implementation of tasks in the three areas, systematic execution is called for, which requires identifying risk factors in advance. In particular, comprehensive risk management role and responsibility is required for program management. Success of a development program is determined by complex elements of human resources, organization culture, and overall competency of an organization in technology and program management, including capability of the program manager. In this paper, a risk management solution is suggested to lead a program to success with a more efficient way through actual risk management by the concept of SE around the above three areas.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.392-392
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• 2006

• Journal of the Korean Society of Systems Engineering
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• v.16 no.1
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• pp.78-83
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• 2020

Recently, the use of domestic products securing domestic technology is encouraged, because of export restrictions of the countries or DMSMS(diminishing manufacturing sources and shortages). Domestic weapon systems are actively focused on the parts localization process of R&D projects based on Systems Engineering. However, it is the only way to do technical review for Systems Engineering process up to now. There is a case of application in Localization with Systems Engineering process, but the SE activity is not enough. This study is how to apply Systems Engineering process to Localization effectively based on real cases.

• Journal of Engineering Education Research
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• v.9 no.2
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• pp.52-70
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• 2006

Systems Engineering(SE), as a special discipline evolved from multidisciplinary and interdisciplinary design knowledges and practical lessons learned from development practices, is required to develop today's ever-growing large complex systems. As computer speed and analytic sophistication accelerate their applications, modern society's needs have become increasingly varied and complex. Rapid advances in Systems Engineering and its education programs among the developed countries demonstrate their needs as an alternative to what is lacking from traditional disciplinary engineering to meet new challenges of our changing social environments. Systems Engineering is an interdisciplinary approach that includes both management and technical processes. Its processes, methods, and tools are used to evolve, define, and verify an integrated, life-cycle balanced set of system solution that satisfy customer needs and requirements. The process methodology offers a top-down comprehensive, iterative and recursive problem solving process which includes the stating the problems, investigating the alternatives, architecting and modeling the system, integrating and operating the system, assessing and re-evaluating the system performances. The purpose of this paper is to research the cases of SE educational programs for both domestic and other developed countries and to propose recommendations for the domestic SE educational programs in the future.

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.130-131
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• 1998

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.458-464
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• 2008

The objective of this paper is to seek an alternative to figure out appropriate ways since difficulties lie in the introduction of LRT system to be operated by governments and self-governing local governments in the country. This situation can act as a main cause of breakdown in domestic railway industry by deepening of outflow of national wealth and technological dependency. Policy makers are required to get awareness of justification and necessity of Project management such as project strategy, goals, operating budgets, risks, investment revenue prior to preparing the outline of the introduction of LRT system shall consider securing budget in light of performance, reliability, and safety withe the help of system engineering activities during the entire project cycle such as design, construction, quality management, and commissioning before mapping out the basic plans for LRT project. In view of the current domestic conditions, the first time within the country, Seoulmetro is training professional as trust education of specialist training about LRT system, SE and PM education. This study leads to participating in PM/SE business by human power who finished from education of domestic specialist for LRT introduction corporation and businesses, it is published for introduction of specialist education and business revitalization.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.1079-1084
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• 2002

Systems engineering technology development program for Korea next-generation high-speed railway(KNHR) system in progress is a national large-scale system development program that is not only a large-size and complex but also multi-disciplinary in nature. Using the RDD-IOO, a systems engineering tool, the KNHR program can establish requirements traceability and development process management in the course of development. This paper presents the results from a computer-aided systems engineering application to KNHR system technology development project over the three years of activities. The traceability among the system design database in the vertical direction of SE process, as the results of the first year and the second year research was accomplished. The database in both the requirement management domain and the project management domain was developed and set up the traceability between them in the horizontal direction of the SE process in the V model as the results of the third year research. Therefore, KNHR design database was built to support the life-cycle management of the system as well as to reuse the knowledge in future programs. In the following development phase, this database will be utilized to accomplish the test and integration activities providing a baseline database. The outcome of the study contributes to the establishment of the model-based systems engineering approach as a best practice in the accumulation and advancement of systems engineering technology for railway system development.