• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.47-55
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• 2015

This paper proposes the installation of a new modular multilevel converter based high-voltage direct current (MMC-HVDC) system to connect between mainland and Jeju island power systems in Korea in 2020. The purpose is to combine with two old line-commutated converters (LCC)-based HVDC system to achieve a stability of the Jeju island power system. The operation of the overall system will be analyzed in three cases: (i) wind speed is variable, (ii) either one of the LCC-HVDC systems is shutdown because of a fault or overhaul, (iii) a short circuit fault occurs at the mainland side. The effectiveness of the proposed control method is confirmed by the simulation results based on a PSCAD/EMTDC simulation program.

• International journal of advanced smart convergence
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• 제2권2호
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• pp.23-26
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• 2013

Social networking services that connect a person to other people are attracting people's attention and various types of services are provided on the Internet. Library has been playing a role of social media by providing us with materials such as books and magazines, and with a place for reading, studying, getting lectures, etc. In this paper, we present a method for finding candidates of groups of the library's patrons who share interest areas by utilizing the loan records, which are obtainable in every library. Such a homogeneous group can become a candidate for a study group, a community for exchange ideas, and other activity group. We apply the method to a collection of loan records of a university library, find some problems to be solved, and propose measures for more detailed solutions. Even though the potential group finding problem still remains a lot of issues to be solved, its potential importance is very high and thus to be studies even more for future applications.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3391-3396
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• 2012

Two-dimensional infrared (2D-IR) spectroscopy can probe the fast structural evolution of molecules under thermal equilibrium. Vibrational frequency fluctuation caused by structural evolution produced the time-dependent line shape change in 2D-IR spectrum. A variety of methods has been used to connect the evolution of 2D-IR spectrum with Frequency-Frequency Correlation Function (FFCF), which connects the experimental observables to a molecular level description. Here, a new method to extract FFCF from 2D-IR spectra is described. The experimental observable is the time-dependent frequency shift of maximum peak position in the slice spectrum of 2D-IR, which is taken along the excitation frequency axis. The direct relation between the 2D-IR peak shift and FFCF is proved analytically. Observing the 2D-IR peak shift does not need the full 2D-IR spectrum which covers 0-1 and 1-2 bands. Thus data collection time to determine FFCF can be reduced significantly, which helps the detection of transient species.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1391-1396
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• 2014

In the present study, ten metal free non-linear optical (NLO) compounds have been designed. These compounds have designed by structural modification of (2-cyano-5-(4-(phenyl(4-vinylphenyl)amino)phenyl) penta-2,4-dienoic acid (TC4). Density functional theory was used for structure optimization and determination of photo-physical properties. These compounds contain triphenylamine as electron-donor and cyanoacrylic acid as acceptor. Five ${\pi}$-spacers are used to connect the donor and acceptor. Two auxiliary donors are also used to assist the donor. Results of this study indicate that stronger electron-donating auxiliary groups and longer ${\pi}$-conjugation enhance NLO response. Major absorption peaks of all systems were in the visible region. These absorption peaks are associated with the ${\pi}-{\pi}^*$ transitions of the entire molecule. From calculations it is clear that all system will be good NLO material. The present calculations will provide new ways for experimentalists to synthesize high-performance NLO material.

• 전자공학회논문지D
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• 제34D권8호
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• pp.1-7
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• 1997

In ahigh power amplifier design, power combiner/divider is used to connect low power amplifiers in parallel. The raidal structure of the powe combiner/divider has not only a good characteristics of port-to-port isolation but also an advantage of giving a redundancy to the structure itself by using RF switches. The parastics of a power resistor, that would be a problem in design process, are removed by both slot lines and cavity resonators, and the comon node in the circuit is rdesigned as a planar topology, and thus a new type of 4-way radial power combiner/divider is accomplished at 1840 ~ 1870 MH PCS frequency band. The insertion loss, reflection, and isolation characteristics of 40way radial power combiner/divider which can be adaptable to PCS system in this thesis are -0.3dB, -24dB,a dn -27dB respectively.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(1)
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• pp.123-126
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• 2004

Demands on dealing with multimedia data through the network have been increased, and networking multimedia devices require processing, transmitting , and receiving the digital data. In order to implement the network for high performance and low cost, we may have to integrate the dedicated hardware into a system on a chip by spending an extra amount of silicon resource. In this paper, we describe hardware implementation of TCP/IP protocol stack which is now popular to connect multiple PCs and peripherals by means of networks. For evaluation we used ALTERA APEX 20K600EBC652 FPGA with 600,000 gates. The operating frequency is estimated 29.9MHz and it used area of $26\%$.

• East Asian mathematical journal
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• 제27권4호
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• pp.381-389
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• 2011

The flexible mathematical thinking - the ability to generate and connect various representations of concepts - is useful in understanding mathematical structure and variation in problem solving. In particular, the flexible mathematical thinking with the inventive mathematical thinking, the original mathematical problem solving ability and the mathematical invention is a core concept, which must be emphasized in all branches of mathematical education. In this paper, the author considered a case of flexible mathematical thinking with an inventive problem solving ability shown by his student via real analysis courses. The case is on the proofs of the equivalences of three different definitions on the concept of limit superior shown in three different real analysis books. Proving the equivalences of the three definitions, the student tried to keep the flexible mathematical thinking steadily.

• Asian Journal of Innovation and Policy
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• 제5권1호
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• pp.55-77
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• 2016

This paper focuses on how an integrated or systemic approach is needed to both investigate and connect different kinds of interdisciplinary inquiry and knowledge within and beyond universities to encourage more productive collaboration with the other three ‘macro stakeholders’ - government, business, and the wider community. In this way universities can and should provide a greater leadership role in sustainability, innovation and policy studies. Such a framework is needed to also help to change the view of many that academics should just play a supporting role of providing specialised technical expertise only to the other macro stakeholders. The interdisciplinary and collaborative framework developed here is applied to the on-going water crisis in Malaysia - an exemplary complex problem-solving basis for seeking sustainable policy solutions to diverse challenges. As further discussed, this was applied also in practice to a multi-stakeholder seminar on addressing the difficult policy challenges of the Malaysian water industry and sector.

• International Journal of Internet, Broadcasting and Communication
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• 제4권1호
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• pp.3-7
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• 2012

Traditionally SCADA is connected only in a limited private network. With new technology and facilities, there are also demands of connecting SCADA though the internet. The internet SCADA facility has brought a lot of advantages in terms of control, data viewing and generation. Aside from connecting SCADA to the internet, there are also operators who want to connect their system wirelessly. This can save budget for communication lines. Along with the advantages it brings, are security issues regarding wireless internet SCADA. In this paper, we discuss internet SCADA, its connection through wireless communication and the security issues surrounding it. To answer the security issues, a symmetric-key encryption for internet SCADA is proposed.

• 수산해양교육연구
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• 제27권6호
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• pp.1832-1841
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• 2015

With the rapid development of global economy and trade, international logistics has made great progress in the past few years. As an irreplaceable part in China's foreign trade industry, ocean shipping, especially. ports management has played a crucial role in the development of China. In 2008, The Qingdao Qianwan bonded port was built in China, and has developed in to a door to connect China to the world. This paper introduced and compared the similarities and differences among the Yangshan Bonded Port, Dalian Dayawan Bonded Port, Tianjin Dongjiang Bonded Port and Qingdao Bonded Port. According to SWOT analysis, a further discussion was then made on the potential problems of Qingdao Bonded Port. At last, some development strategies are given accordingly.