• Journal of Korea Multimedia Society
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• v.13 no.7
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• pp.933-942
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• 2010

The convergence of the telecommunication industry through the combination of existing network technology and multimedia technology has brought along interactive data services in addition to the traditional broadcast services by providing direct connections between the users and the broadcasters. The interactive data service technology has developed a network which is able to fully support QoS and also a fast enough channel changing technology that is satisfactory to the user, are prerequisites for IPTV success, to provide satisfactory levels of service to exist users. However the current server-client system can't support all increasing needs of users. To overcome these limitations, P2P based IPTV service is currently under researched. Therefore, this thesis proposes a logical view based copy-ahead technique for P2P IPTV to improve the performance of IPTV system.

• The Journal of Information Systems
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• v.10 no.1
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• pp.27-50
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• 2001

The purpose of this study was to examine some of the most important factors for the development of information systems with today's fast-paced, ever-changing, and exciting information system environment. Especially, it was focused to investigate current information technology related to develop information systems, to find some important problems during the development process, and to suggest solutions for the problems. Case research methodology was used because a natural setting was needed and a focus was on contemporary events for this study. Similarly, research phenomena was not supported by a strong theoretical base. The case was the development of an integrated information systems in a specific university. Multiple-case designs were desirable, but single-case study was used because of limitations of site selection. Multiple data collection methods were employed in this study such as documentation, interviews, and direct observation. Some major problems were found during the system development. First, the schedule to complete a project was delayed over six months. Second, the system did not ensure to align organizational goals and information systems goals based on BPR (Business Process Reengineering). Third, there was a difficulty in evaluating request for proposal (RPR) returns and choosing a vendor. Finally, information technology is changing too fast. So, it was very difficult to get the transparency of new technology The study has suggested a few solutions: top management support, matching If planning with business planning, complete project plan and control, user participation, and training Finally, joint application development (JAD) is strongly recommended, which is a workshop that unites management, IT specialists, and knowledge workers to define and specify the logical requirements and technical alternatives for a proposed system.

• Journal of Integrative Natural Science
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• v.15 no.3
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• pp.99-110
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• 2022

Solar photovoltaic (PV) system shows a non-linear current (I) -voltage (V) characteristics, which depends on the surrounding environment factors, such as irradiance, temperature, and the wind. Solar PV system, with current (I) - voltage (V) and power (P) - Voltage (V) characteristics, specifies a unique operating point at where the possible maximum power point (MPP) is delivered. At the MPP, the PV array operates at maximum power efficiency. In order to continuously harvest maximum power at any point of time from solar PV modules, a good MPPT algorithms need to be employed. Currently, due to its simplicity and easy implementation, Perturb and Observe (P&O) algorithms are the most commonly used MPPT control method in the PV systems but it has a drawback at suddenly varying environment situations, due to constant step size. In this paper, to overcome the difficulties of the fast changing environment and suddenly changing the power of PV array due to constant step size in the P&O algorithm, least mean Square (LMS) methods is proposed together with P&O MPPT algorithm which is superior to traditional P&O MPPT. PV output power is predicted using LMS method to improve the tracking speed and deduce the possibility of misjudgment of increasing and decreasing the PV output. Simulation results shows that the proposed MPPT technique can track the MPP accurately as well as its dynamic response is very fast in response to the change of environmental parameters in comparison with the conventional P&O MPPT algorithm, and improves system performance.

• Progress in Superconductivity and Cryogenics
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• v.13 no.1
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• pp.41-45
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• 2011

Hybrid fault current limiters (FCL) have been researched at Yonsei University. The hybrid FCL has advantages such as having a rapid response to a sudden fault situation and a fast recovery time from a quench. It consists of an asymmetric HTS coil, a switching module, and a bypass reactor. The asymmetric HTS coil is wound with two different types of HTS wires in an opposite direction so that it has nearly zero inductance at the superconducting state. When the quench occurs at the fault state, a strong magnetic field is generated from the asymmetric coil because of different quench characteristics of two HTS wires, and then a repulsive force is induced in the switching module. The force opens the switch and the fault current is pushed into the bypass reactor. In this research, we analyzed the cause of the repulsive force and confirmed, experimentally and computationally, that the magnitude of a repulsive force is varied by changing the gap distance between the asymmetric coil and the switching module. By using the FEM simulation, we calculated the repulsive force with respect to the gap distance and verified that the effect of the gap distance. Then, short circuit test was carried out to confirm the correct operation of the fast switch.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.2
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• pp.91-100
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• 2015

The environment of using digital devices has been developed day by day, as mobile communication network has been fast and smart phone and tablet PC have been spread. When the environment changing, the contents consumers prefer have been changing too. The Webtoon became the representative contents of 'Snack culture'. The webtoon has led the growth of cartoon market for years recently instead of the slow comics growth. And it places its elf as contents on a firm basis, as it has been adapted to another genre such as Pay, Flm, TV Drama. Now it's expected to be an extgeneration contents that will lead Han-ryu(Korean wave). Though the webtoon has important and strong presence, there is no digital archive for collecting and preserving the webtoon, Korean Cartoon Contents Agency started making 'webtoon archive', but the groundwork and the study on the webtoon that represents digital culture contents are not enough a lot. In this study, the cases on digital archiving of culture contents in Korea are researched, and the direction on webtoon archiving that has just started is also discussed. The Archiving of webtoon that can't be seperated from digital contents is connected with archiving of digital culture contents in direction where they should be headed to.

• Journal of the Korean Society of Clothing and Textiles
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• v.42 no.4
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• pp.708-725
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• 2018

The advancement of digital technology has made changes in the fashion system and trend development process inevitable. This article clarifies changes in the modern fashion industry system and the causes of comprehensive changes that result from the development of digital technology. The methodology of this study is based on literature and case studies based on the information magazine most used by fashion industry workers. This study classifies fashion systems into 5 types and 14 types in detail. The study results indicate the way to change the fashion style trend schedule per year, fast/ultrafast fashion system, fashion rental system, DTC system and change of fashion system by consumer participation. The causes of the changes in fashion system are indicated that an increase of trend sensitivity due to an increase in the diffusion rate of information, expansion of expression of personality through digital network, increase of possibility of grouping of small number of tastes and change of prosumer possible changes in the environment. This study provides basic data on fashion system research and the construction of an appropriate response strategy for a changing environment.

• Proceedings of the KSCN Conference
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• 2005.10a
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• pp.33-38
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• 2005

During the 20th century, humankind went through the most significant changes in history, from industrial and agricultural revolutions to the invention of the personal computers and the internet, and changes continue to come at an even faster rate. One of notable change is emerging multicultural societies. People tended to live in a monocultural society and new cultures were infused in controlled and confined manners, however, people now live and eat in a continuously changing multicultural society Multicultural societies are emerged from the translocation of people (immigration) and, in a larger sense, globalization. Immigrants are faced with various and different cultures from their own, resulting in excitements and agonies in finding balance among many cultures. People who have not translocated themselves must also deal with various imported foreign cultures from fastfood restaurants to food beliefs. This lecture will use Korean Americans as an example to discuss how immigrants navigate different cultures and environments and how acculturation, the process of adaptation, affects their diet and health. In addition, how globalization has changed people's eatery will be briefly discussed. Understanding impacts of living and eating in a multicultural society is meaningful and useful to find effective approaches to promote healthy lifestyles to people in this fast changing times.

• Journal of Korean Society on Water Environment
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• v.30 no.3
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• pp.304-310
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• 2014

The conventional methods for total residual chlorine such as iodometry and DPD colorimetric can cause secondary pollution due to additional agents, also have a wide error range. As for alternative, electrochemical method can measure TRC(Total residual chlorine), and is not required as additional agents, also very suitable for using the fields of ballast water because test time is relatively fast. Therefore, this study was investigated for changing charge by agitation, salt concentration, and temperature change. Charge showed differences based on changes of reduction peak with or without agitation. In contrast, TRC and charge were well correlated in constant agitation speed. As TRC and charge were analyzed with high correlations in constant salinity and temperature of ocean, thereby conductivity was firstly measured, and charge had high correlation for TRC in spite of changing salinity and temperature Pt electrode revealed high reliability ($r^2=0.960$) because it was rarely effected by TRC, On the other hand, Au electrode appeared inadequate ($r^2=0.767$) to use sensor in less than 1.0 ppm of TRC. For high accuracy and detection of TRC, Pt and Au electrodes for test time were, respectively, 14 and 22 seconds. As a result, Pt electrode was more valuable than Au electrode in terms of response time.

• Korean Institute of Interior Design Journal
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• no.41
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• pp.146-154
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• 2003

The purpose of this study is, According to society changing fast, human life is changing in the direction of complexity and variety, the middle class and multiple structure have been generated in relation between architecture and function. Accordingly, considering the analyzed elements of the main floor space planning and relation of the factors in space planning of Seoul s public libraries. The Public Library is variety of function is abstracted to the plan for Space Composition Form from future public library, analysis of “This point of user, how to composition is the space of different function” and “How to is the connection between the educational function and the other function, complexity of space.” With above distinctive themes and the research, the typology of public library in seoul city, At the first, the research shows that the public library is 8 type, and high in typology of “TYPE 7 (A3-B2-Cl)”. Secondary, There appears public library, such as in the satisfaction of the One-Function-User is high in “TYPE 3 (A1-B2-C3)”, in the satisfaction over the Two-Function-User is high in “TYPE 6 (A3-B1-C1)”

• Journal of Practical Engineering Education
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• v.6 no.1
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• pp.65-70
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• 2014

Nowadays, technologies are changing so fast as due to the advancement of industrial structure, and those situations require the change in the curriculum and educational method of vocational high schools. To satisfy those requirements, field-oriented training program was designed and operated. In this research, we evaluated and analyzed short medium and long term field-oriented training program operated by KOREATECH Human Resource Development Institute (HRDI) in 2013. Evaluation results shows that the satisfaction about field-oriented training is very high, and we propose improvement scheme in order that the field-oriented training can be established as a proper program to cope with the changing industry and technologies.