• Journal of The Korean Association of Information Education
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• v.8 no.3
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• pp.335-349
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• 2004

Recently, there is change the environment of education due to development of Science Technology Specially, As education information on web increased by internet, using education web data by mean of medium that aids learning by computer. Also It studied method that used the Computer as learning medium through the CAI(Computer Assisted Instruction), ICAI(Intelligent CAI), and ITS(Intelligent Tutoring System). But legacy system are not support efficient method that learns to vary learner suitable learning method by individual level. Specially It is not suitable the education course to direct current course of education, and not consider different of student capability, aptitude, need, interesting, not maximized the individual growable power and effect of education. To solve the this problem, our paper suggest the web-based self-directed MITS(Multimedia ITS) that supply the needed the information on web, make the environment that can self-directed learning. To maximized effect of individual learning, our paper structured coursed, characterized, related learning contents in region of numeral at mathematics of primary school. And then integrated contents and class, design and implement the web-based MITS that consist of 4 module to escape from limitation of learner grade, learning time, learning place.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.1
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• pp.7-19
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• 2019

This study was conducted in order to improve opening efficiency of the miniaturized small-scale net for anchovy boat seine gear to reduce the fleet size. Field experiment was performed to observe geometry of nets by catcher boats. When the distance between the two ships was 150, 300 and 450 m and the speed of towing nets was 0.6, 0.9, and 1.2 kt, the vertical opening and actual opening of each part of the miniaturized small-scale net was as follows: the front part of the wing net, 6.8-9.5 m, 45-63%; the middle part of the wing net, 16.1-30.7 m, 34-65%; the entrance of the inside wing net, 21.6-41.2 m, 44-84%; the square and bosom, 17.4-34.0 m, 38-75%; the entrance of the body net, 16.5-29.4 m, 36-64%; the entrance of the bag net, 14.5-21.9 m, 70-106%; the flapper, 6.7-7.7 m, 81-83%, and the end of the bag net, 8.6-10.9 m, 64-81%. The tension of towing nets was measured to be 2,734-6,812 kg approximately, which indicates that the fleet can tow nets with 350 hp, the standard engine horse power. The fishing operation time was shortened comparing to existent net with the large-scale buoy attachment operation. It was also possible to operate the ship without fish detecting boat.

• Journal of Ocean Engineering and Technology
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• v.31 no.3
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• pp.202-207
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• 2017

This paper presents the results of an experimental study on the motions and mooring characteristics of a floating vertical axis wind turbine system. Based on a comparison of regular wave experiment results, the motions of structures with different types of mooring are almost the same. Based on the tension response results of a regular wave experiment with a catenary mooring system, the mooring lines in front of the structure have a larger tension effect than the back of the structure by the drifted offset of the structure. The dynamic response spectrum of the structure in the irregular wave experiments showed no significant differences in response to differences in the mooring system. As a result of the comparison of the tension response spectra, the mooring lines have a larger value with a drifted offset for the structure, as shown in the previous regular wave experiment. The results of the dynamic response of the structure under irregular wave and wind conditions showed that the heave motion response is influenced by the coupled effect with the mooring lines of the surge and pitch motion due to the drifted offset and steady heeling. In addition, the mooring lines in front of the structure have a very large tension force compared to the mooring lines in back of the structure as a result of the drifted offset of the structure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10A
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• pp.760-768
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• 2009

In this paper, we propose the energy efficient transmission parameter selection method for Wireless Personal Area Network (WPAN) system which is applied to e-Navigation system considering various ship models environment. An appropriate selection of transmission parameters of HR-WPAN system is very essential to be considered for saving WPAN devices' energy consumption, when HR-WPAN system is applied to ship area network (SAN). Therefore, we propose an energy consumption model for a ship area network employing IEEE 802.15.3 based CSMA/CA HR-WPAN model and analyze the effect of transmission parameter selection on the performance of energy consumption. In particular, the path loss is the major performance decision parameter for the SAN employing HR-WPAN system, since it varies according to the material of shipbuilding such as steel(for large ship), FRP(for medium size ship) and compound wood(for small ship). Thus, we analyze and demonstrate that the proper transmission parameter selection of transmit power, PHY data rate and fragment size for each ship model could guarantee energy efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.12
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• pp.2765-2772
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• 2015

In Korea MVNO was introduced in 2011 when twenty seven years had passed since Korea Mobile Telecom(now SK Telecom) started mobile phone service. MVNO can make competition more effective to lower communication costs through the alternatives. In the early 2000s, the need for the introduction of the MVNO has been raised already by scholars in Korea. But it wasn't until the late 2000s when rate cuts appeared to be a major policy issue, and Korean government introduced MVNO. In April 2015, MVNO's market share reached 8.8%, but Korea does not have a firm system yet. This rapid growth of MVNO market in Korea was made possible by consumers' demand for cheaper services and late introduction of MVNO. And telecom companies(MNO) abuse their supreme power against small and medium firm MVNOs and reserved market share using their subsidiary companies. Thus proper regulation is necessary. However, the government authorities should have recognized global MVNO flow quickly and have to make a sufficient effort to establish proper competition condition of the mobile telecom market.

• Journal of Sensor Science and Technology
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• v.24 no.4
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• pp.264-269
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• 2015

An infrared (IR) bolometer measures the change of resistance by absorbing incident IR radiation and generates a signal as a function of the radiation intensity. Since a bolometer requires temperature stabilization and light filtering except for the infrared rays, it is essential for the device to be packaged meeting conditions that above mentioned. Minimization of heat loss is needed in order to stabilize temperature of bolometer. Heat loss by conduction or convection requires a medium, so the heat loss will be minimized if the medium is a vacuum. Therefore, vacuum packaging for bolometer is necessary. Another important element in bolometer packaging is germanium (Ge) window, which transmits IR radiation to heat the bolometer. To ensure a complete transmittance of IR light, anti-reflection (AR) coatings are deposited on both sides of the window. Although the transmittance of Ge window is high for IR rays, it is difficult to use frequently in low-price IR bolometer because of its high price. In this paper, we fabricated IR window by utilizing silicon (Si) substrate instead of Ge in order to reduce the cost of bolometer packaging. To enhance the IR transmittance through Si substrate, it is textured using Reactive Ion Etching (RIE). The texturing process of Si substrate is performed along with the change of experimental conditions such as gas ratio, pressure, etching time and RF power.

• Proceedings of the Korea Contents Association Conference
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• 2004.05a
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• pp.241-260
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• 2004

Trade portal site is one of the tools which makes it possible for small and medium-sized enterprises(SMEs) to manage international trade activities more efficiently by using the newest information and telecommunication technology. So Korean SMEs should utilize trade portal sites more actively to promote global competitive power. Based on the theory of service quality and an existing research related to using information technology. this research analyzed the primary factors which affect user's utilization satisfaction in using trade portal sites. According to the results of the empirical study on actual users of the representative trade portal sites by using multiple regression analysis, The primary factors, such as service quality, government policy and cost have affected user's utilization satisfaction in using trade portal site. and user's utilization satisfaction have positive effect on continuous using intention. These research results will provide many useful insights to the managers of trade portal sites, e-trade system developers and government policy makers.

• The Journal of the Korea Contents Association
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• v.4 no.3
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• pp.21-40
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• 2004

Trade portal site is one of the tools which make it possible for small and medium-sized enterprises(SMEs) to manage international trade activities more efficiently by using the newest information and telecommunication technology. So Korean SMEs should utilize trade portal sites more actively to promote global competitive power. Based on the theory of service quality and existing researches related to using information technology, this paper analyzed the primary factors which affect user's utilization satisfaction in using trade portal sites. According to the results of the empirical study on actual users of the representative trade portal sites by multiple regression analysis, the primary factors, such as service quality, government policy and cost factor have affected user's utilization satisfaction in using trade portal sites. And user's utilization satisfaction have positive effect on continuous using intention. These research results will provide many useful insights to trade portal site managers, e-trade system developers and government policy makers.

• Journal of Korea Multimedia Society
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• v.13 no.10
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• pp.1494-1505
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• 2010

A variety of sounds take place in medium and small-sized manufactories producing many kinds of parts in a small quantity with one press. We developed the identification system for the quality of parts using HTM(Hierarchical Temporal Memory)-based sound recognition. HTM is the theory that the operation principle of human brain's neocortex is applied to computer, suggested by Jeff Hopkins. This theory memorizes temporal and spatial patterns hierarchically about the real world, which is known for its cognitive power superior to the previous recognition technologies in many cases. By applying the HTM model to the sound recognition, we developed the identification system for the quality of molding parts. In order to verify its performance we recorded the various sounds at the moment of producing parts in the real factory, constructed the HTM network of sound, and then identified the quality of parts by repeating learning and training. It reveals that this system gets an excellent and accurate results at the noisy factory.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.1
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• pp.189-194
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• 2021

With the recent increase in the proportion of single-person households, starting in 2016, the domestic shared personnel mobility market such as electric kickboards and electric wheels has grown rapidly. Personal transportation means such as electric kickboards are power devices using electricity and are eco-friendly, lightweight, and do not occupy a separate parking space. Above all, it has the advantage of being convenient to travel short and medium distances, so it has been able to obtain a lot of demand from younger users who pursue reasonable consumption, and accordingly, the related market has grown rapidly. However, as absence of the charging station for electric kickboards, electric kickboards are left everywhere on the road, and are emerging as a threat to safety as well as aesthetics. Therefore, this paper aims to research and propose a new IoT management system for efficient recovery of shared electric kickboards. Through this system, it is expected that the high recovery rate of the electric kickboard can be maintained, and in conclusion, the safety of the user and the surrounding environment can be improved.