• Vacuum Magazine
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• v.3 no.3
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• pp.4-9
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• 2016

Nanowires have excellent properties such as high crystallinity, good mechanical properties, quantum confinement effect and high chemical activity, and thus are promising building blocks for many applications. Here we firstly review the fabrication of nanowires by top-down and bottom-up process. We then review nanowires as building blocks for bio applications including bio sensing, cell signaling and cell stimulating. It shows that nanowires are promising for the development of advanced bio technologies that can address ultrahigh sensitivity, and long term cell signaling and stimulating without cell damages.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.722-729
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• 2007

The methodology for maintenance system development should overall be considered with all of task characteristic, schedule, and the technical condition of investment sources. This research applies Waterfall model to methodology for the development and construction of maintenance system through customizing the CD (Custom Development) procedure of "HSDM (Hyundai System Development Methodology)" based on information engineering. The waterfall model called as classic life cycle paradigm is defined for the sequent development procedure, which make progress a next step after that a previous step is admitted with thorough review. This model which is popular and the oldest paradigm is used for system development by four steps; demands analysis, design, construction, and maintenance. This methodology advances higher abstract step from higher lower step using top-down approach from concept definition to construction, which notices the end of a step whenever a step is over. Therefore, each step is exactly divided, and consequently the output is clearly yielded.

• ETRI Journal
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• v.17 no.3
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• pp.1-16
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• 1995

An advanced real-time satellite simulator (ARTSS) has been developed to support the ground operations activities of the ETRI satellite control system, such as testing of the system facilities, validation of flight control procedures, verification of satellite commands as well as training of the ground operators. The design of ARTSS is based on the top-down approach and makes use of a modular programming to ensure flexibility in modification and expansion of the system. Graphics-based monitoring and control facilities enhance the satellite simulation environment. The software spacecraft model in ARTSS simulates the characteristics of a geostationary communication satellite using a momentum bias three-axis stabilization control technique. The system can be also interfaced with a hardware payload subsystem such as Ku-band communication transponder to enhance the simulator capability. Therefore, ARTSS is a high fidelity satellite simulation tool that can be used on low-cost desk top computers. In this paper, we describe the design features, the simulation models and the real-time operating functions of the simulator.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.819-829
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• 2008

Fatigue cracking occurs over long time period because dynamic strength of slab continuously decreases by vehicle loading repetitively applied to the concrete pavement. To more accurately predict the fatigue life of the concrete pavement, the stress due to environmental loading should be considered prior to calculating the stress due to the vehicle loading because the stress due to temperature and moisture distribution always exists within the slab. Accordingly, a new fatigue model considering the environmental loading was developed in this research by evaluating factors of existing fatigue models most widely used and by making data points from the models. The applicability of the new model was evaluated by performing a fatigue analysis on the general concrete pavement structure using local climatic and traffic conditions in Korea. It was concluded that the top-down cracking due to the tensile stress at top of the slab is dominant cause of the fatigue failure than the bottom-up cracking occurred at bottom of the slab. More advanced fatigue analysis considering vehicle speed is expected by developing this study.

• International Journal of Contents
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• v.15 no.2
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• pp.38-43
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• 2019

Recently, bottom-up information systems (BUIS), developed according to the requirements of individual user departments, have become popular. However, effective management of BUIS projects is not enough, with many organizations having experienced integration challenges with such individual projects. BUIS projects are relatively small and limited in scope, as opposed to the large, complex systems developed through traditional top-down information system development projects. Due to these differences in characteristics, the control modes as well as the aspects to improve development performance in each type of project are also different. Therefore, it is difficult to apply the results of prior research on control in system development projects to improve BUIS project performance. The purpose of this study is to derive a new theory of control to improve BUIS project performance. The results contribute to the improvement of firm performance through effective control of BUIS projects in modern enterprises.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.1
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• pp.22-29
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• 1999

Biological and chemical characteristics and trophodynamics in the frontal zone were investigated in the southern waters of Korea, Temperature, nutrients (dissolved inorganic nitrogen, $PO_4^{3-}-P$, and $SiO_2^{-}-Si$) chlorophyll a and zooplankton were collected and analyzed along the two transects, the frontal zone and the non-frontal zone, in April, 1994. Nutrients were higher in the non-frontal zone than in the frontal zone. But chlorophyll a concentration was high in the frontal zone, particularly at the 20 m depth of the main frontal station (St. TII-2), where was located at the junction between the stratified layer and the non-stratified layer with the lowest nutrients. Zooplankton was more abundant in the frontal zone than in the non-frontal zone, particularly at the innermost station of the frontal zone. Copepods showed high composition rate more than $90\%$ at all stations except the main frontal station (St. TII-2). At the main frontal station (St. TII-2), euphausiids and siphonophores were dominated. Chlorophyll a revealed a significant relationships with $SiO_2^{-}-Si$ in both transects and copepods in the non-frontal zone. Copepods also showed very close relationship with siphonophores in the frontal zone. This suggests that the abundance of copepods could be controlled as bottom-up in the non-frontal zone and as top-down in the frontal zone.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.3
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• pp.44-51
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• 2001

In general, the realization of spaceborne system is constrained by its space environment. In this paper, we suggest chirp stitching technique which generates and processes wideband radar signal with minimum hardware, design and implement transmit/receive equipments and operating programs to satisfy the requirement of this spaceborne high resolution SAR(Synthetic Aperture Radar). We apply the top down design approach to this system, and divide hardware into equipment, module and circuit levels, and software into SR(Software Requirement), AD(Architecture Design), DD(Detailed Design) and coding levels, and then extract each requirement to satisfy the wideband requirement of this spaceborne high resolution SAR. We, at first, test the hardware functions, confirm the wideband handling capability of this system with 85MHz wideband signals generated from two 42.5MHz narrow band signals, and show that this system can be used in spaceborne high resolution SARs.

• Journal of Korean language education
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• v.29 no.1
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• pp.109-137
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• 2018

The purpose of teacher education is to improve the professionalism of teachers above the current level. The type of teacher education to improve the professionalism of experienced teachers is broadly divided into top-down education and bottom-up education. So far, studies on top-down education were commonly conducted in the field of Korean language education. However, there has been an increasing number of studies emphasizing the need for bottom-up education, driven by the voluntary participation of teachers in recent years. The purpose of this study is to suggest the direction of reflective teacher education for experienced Korean language teachers. For this purpose, a survey was conducted of 71 Korean language teachers who had more than 5 years of experience. The contents of the survey consisted of opinions regarding existing teacher education, the need for reflective teacher education, and the perception of teaching professionalism. The results showed that experienced Korean language teachers had a positive perception of the existing teacher re-education experience. Also, 91% of the respondents said they intend to participate in the reflective teacher education program. In particular, respondents showed high demands for 'peer coaching', 'peer observation', and 'teaching portfolios' among reflective teacher education programs. Lastly, many respondents selected 'development and utilization of teaching materials', 'encouraging learner's utterances', and 'leading learner's interest and motivation' as sub-elements of teaching professionalism that they wish to improve through teacher re-education.

• Health Policy and Management
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• v.29 no.3
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• pp.245-247
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• 2019

Although 19 years have passed since the enforcement of the Framework Act on Health and Medical Services, the Plans for Development of Health and Medical Services has not been established. This Plan is a 5-year basic long-term plan that covers the whole of health and medical services. This Plan should point to the direction of 30 long-term plans of healthcare, and this Plan should serve as a combination and coordination of 30 long-term plans and 22 related laws. The United States, the United Kingdom, and Japan have established long-term healthcare plans (4-, 10-, and 20-year plans, respectively). The long-term health plan of the United States has been approached bottom-up, those of the United Kingdom and Japan have been approached top-down. The rapid environmental changes that Korea is and will be experiencing emphasize urgently the need for establishing the Plan for Development of Health and Medical Services.

• Journal of the Korean Society of Visualization
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• v.12 no.1
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• pp.18-24
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• 2014

The Korea Atomic Energy Research Institute (KAERI) has a scaled-down moderator test program to simulate the CANDU6 moderator circulation phenomena during steady state operation and accident conditions. In the present work a preliminary experiment using a 1/8 scaled-down moderator tank has been performed to identify the potential problems of the flow visualization and measurement in the scaled-down moderator test facility. With a transparent moderator tank model, a velocity field is measured with a Particle Image Velocimetry (PIV) technique under an isothermal state. The flow patterns from the inlet nozzles to the top region of the tank are investigated using PIV for a 1/8 scale moderator tank.