• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.6
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• pp.348-352
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• 2016

In this paper, GaN film was grown on AlN/PSS by hydride vapor phase epitaxy compared with GaN on planar sapphire. Thin AlN layer for buffer layer was deposited on patterned sapphire substrate (PSS) by metal organic chemical vapor deposition. Surface roughness of GaN/AlN on PSS was remarkably decreased from 28.31 to 5.53 nm. Transmittance of GaN/AlN grown on PSS was lower than that of planar sapphire at entire range. XRD spectra of GaN/AlN grown on PSS corresponded the wurzite structure and c-axis oriented. The full width at half maximum (FWHM) values of ${\omega}$-scan X-ray rocking curve (XRC) for GaN/AlN grown on PSS were 196 and 208 arcsec for symmetric (0 0 2) and asymmetric (1 0 2), respectively. FWHM of GaN on AlN/PSS was improved more than 50% because of lateral overgrowth and AlN buffer effect.

• The Korean Journal of Emergency Medical Services
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• v.19 no.2
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• pp.83-97
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• 2015

Purpose: Although appointed as a national competency standards (NCS) based reserves department, the department of emergency medical technology, an NCS-based emergency department, is mainly focused on subject deduction for a NCS-based curriculum. Methods: Job models were formed and verified by combining the competency unit of NCS and the duty of Developing a curriculum (DACUM) based on the development procedure indicated in the guidelines for a NCS-based curriculum. The mapping method of the subject was performed by deducting necessary competency units (duty) and competency unit elements (task) by connecting with the composition items of NCS and DACUM. Results: Job models combined with job analysis for the NCS and DACUM were reduced to 13 competency units (duty) and 79 competency unit elements (task). A modified method such as the 1:N method was mainly applied as a subject-matching method with consideration of the competency level and size of the competency unit. Conclusion: It would be a desirable direction to develop a NCS-based curriculum in the center of the practice subject in consideration of the size of the competency unit and competency level of the competency unit element. The existing curriculum should be promoted as a field-oriented curriculum at the complementary level.

• Geomechanics and Engineering
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• v.14 no.2
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• pp.141-149
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• 2018

In this paper, the creep behavior of bolted rock was analyzed by using the unconfined creep tests and the numerical results. Based on the test results, the Bolted Burgers creep model (B-B model) was proposed to clarify the creep mechanism of rock mass due to rock bolts. As to the simulation of the creep behaviour of bolted rock, a new user-defined incremental iterative format of the B-B model was established and the open-source $FLAC^{3D}$ code was written by using the object-oriented language (C++). To check the reliability of the present B-B creep constitutive model program, a numerical model of a tunnel with buried depth of 1000 m was established to analyze the creep response of the tunnel with the B-B model support, the non-support and the bolt element support. The simulation results show that the present B-B model is consistent with the calculated results of the inherent bolt element in $FLAC^{3D}$, and the convergence deformation can be more effectively controlled when the proposed B-B model is used in the $FLAC^{3D}$ software. The big advantage of the present B-B creep model secondarily developed in the $FLAC^{3D}$ software is the high computational efficiency.

• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.559-564
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• 2024

Since the era of industrial revolution, the waste volume has continued to grow; waste management has thus become one of the major global environmental challenges facing humanities today. Waste treatment and management issues trigger NIMBY movements, and disputes among states, governments, and social actors over the issues have been accelrating. At the level of states and sub-states, various measures including institutions, laws, regulations, market-oriented methods, consensus and collaborative governance have been introduced to address various problems associated with waste. More recently, science and technology has been applied to the waste treatment and management under the notion of circular economy. However, societal support for addressing waste problems still remains inadequate, calling for new approaches and alternative pathways. In this context, this study examines two cases of urban incineration plants designed by Hudertwasser, Austria-born artist and architect: Spittelau, Austria, and Osaka, Japan. Through these case studies, I demonstrate how creative and innovative culture-technology convergence can shed new light on challenging environmental issues such as an urban waste problem.

• Journal of Space Technology and Applications
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• v.4 no.2
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• pp.87-104
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• 2024

CubeSats are being utilized in various fields such as Earth observation, space exploration, and verification of space science and technology due to their low cost, short development period, enhanced mission-oriented performance, and ability to perform various missions through constellation and formation flights. Recently, as the availability of CubeSats has increased and their application areas have expanded, the demand for high-speed transmission of large amounts of data obtained by CubeSats has increased unprecedentedly. Laser-based free space optical communication technology is capable of transmitting large amounts of data at high speeds compared to the existing radio communication methods, and provides various advantages such as use of unlicensed spectrum, low cost, low power, high security characteristics, and of use a small communication platform. For this reason, it is suitable as a high-performance communication technology to support CubeSat missions. In this paper, we will present the core components and characteristics of CubeSat-based space laser communication system, and recent research trends, as well as representative technology development results.

• The Korean Journal of Ceramics
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• v.6 no.2
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• pp.120-123
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• 2000

The geopolymer technique may be a future-oriented technology for saving energies and resources. This technique requires 3 fundamental elements so-called filler, hardener and geopolymer liquor being generally an alkaline silicate solution. Quartz powder, water quenched granulated blast furnace slag and sodium silicate solution prepared from $Na_2O\cdot2SiO_2$were chosen for these three elements. After mixing these starting materials in appropriate proportions, monoliths were prepared by casting at room temperature. Strength tests showed the following results for 28d age speciment: 7.9-12.7 MPa in flexural strength and 20.2-32.8 MPa in compressive strength, depending on geopolymer liquor/solid ratio, P/S and fineness of the quartz powders used.

• Macromolecular Research
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• v.12 no.6
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• pp.564-572
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• 2004

Modem applications could benefit from multifunctional materials having anisotropic optical, electrical, thermal, or mechanical properties, especially when coupled with locally controlled distribution of the directional response. Such materials are difficult to engineer by conventional methods, but the electric field-aided technology presented herein is able to locally tailor electroactive composites. Applying an electric field to a polymer in its liquid state allows the orientation of chain- or fiber-like inclusions or phases from what was originally an isotropic material. Such composites can be formed from liquid solutions, melts, or mixtures of pre-polymers and cross-linking agents. Upon curing, a 'created composite' results; it consists of these 'pseudofibers' embedded in a matrix. One can also create oriented composites from embedded spheres, flakes, or fiber-like shapes in a liquid plastic. Orientation of the externally applied electric field defines the orientation of the field-aided self-assembled composites. The strength and duration of exposure of the electric field control the degree of anisotropy created. Results of electromechanical testing of these modified materials, which are relevant to sensing and actuation applications, are presented. The materials' micro/nanostructures were analyzed using microscopy and X-ray diffraction techniques.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.7 no.2
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• pp.154-158
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• 2007

As the technology developed, the system is being developed as the structure that is adapted to the intelligent environment. Therefore, the existing situation information system couldn't provide satisfactory service to the user as it provides service only by the information which it received from the sensor. This paper analyzed the problems of the existing user intention awareness system and suggested user intention awareness system to provide a stable and efficient service that fits to the intention of the user compensating this. This paper has collected the behavior data based on the scenario of the sequential behavior course of the user that occurs at breakfast time in the kitchen which is the home domain environment thai is closely related to our lives. This scenario course also showed the flow that the goal intentional user intention awareness system acted that it suggested, and showed the sequential course processing the user behavior data by tables and charts.

• Proceedings of the Korea Association of Information Systems Conference
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• 2003.05a
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• pp.169-181
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• 2003

As growth of the web-based applications, the requirements of the users who have been very familiar to the web-based user interfaces and customer-oriented services on the Internet would become more knowledge-intensive and higher technology involved in a more convenient and polite way of service delivery. Therefore, the service quality of information system department should be considered as a very important factor influencing success of information systems. The objective of this study is to provide the relationship between service quality of IS department and its impacts such as use, user satisfaction and job performance. For this purpose, we provide a research model for it and test it empirically for the users of the corporate portal in one of main telecommunication service providers in Korea. In result, our model with satisfiable validity and reliability shows not only importance of IS departments' service quality but also two-faced characteristics of service quality. That is, while technical competence which means with knowledge and expertise of IS department staffs is more related with user satisfaction on information systems, personal service which means the way and manner of service delivery is more related with use of it.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1434-1439
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• 2011

The purpose of this study is based on the optimize the system life cycle cost apply to the advanced systems engineering techniques consideration thought to the system life cycle for the power system which is the one of the major component of the light rail transit system. Generally, the systems engineering techniques apply to the LRT's power systems are not optimize the whole life cycle cost of the power systems because systems engineering management activities are concentrate in performing the key-technology oriented at the construction stage of the dedicated power systems for light rail transit. Through this study, All the stakeholders can be utilize a this advanced systems engineering techniques which is fully considered the life cycle cost through the considering in whole system life cycle (such as concept, design, operation, maintenance and dispose stage as well as construction stage) and adopted by KSX ISO/IEC 15288 system life cycle processes.