• Journal of the Korea Society of Computer and Information
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• v.18 no.9
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• pp.121-129
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• 2013

This paper proposes a linear-time algorithm that has been designed to obtain an accurate solution for Dominating Set (DS) problem, which is known to be NP-complete due to the deficiency of polynomial-time algorithms that successfully derive an accurate solution to it. The proposed algorithm does so by repeatedly assigning vertex v with maximum degree ${\Delta}(G)$among vertices adjacent to the vertex v with minimum degree ${\delta}(G)$ to Minimum Independent DS (MIDS) as its element and removing all the incident edges until no edges remain in the graph. This algorithm finally transforms MIDS into Minimum DS (MDS) and again into Minimum Connected DS (MCDS) so as to obtain the accurate solution to all DS-related problems. When applied to ten different graphs, it has successfully obtained accurate solutions with linear time complexity O(n). It has therefore proven that Dominating Set problem is rather a P-problem.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.2
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• pp.219-226
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• 2019

This paper describes the development of a 500W DC/DC converter for use with a thermoelectric module(TEM). A thermoelectric device is a structure in which a P-type semiconductor and an N-type semiconductor are electrically connected in series and thermally connected in parallel. There is a feature that an electromotive force is generated by making a temperature difference between both surfaces of a thermoelectric element. This feature can be used as a renewable power source without the need for fossil energy. The proposed converter boosts the low generation voltage of the thermoelectric element to secure the voltage for the grid connection. This converter is a combination of a resonant converter for boosting and a boost-converter for output voltage control. This structure has an advantage that a voltage can be stepped up at a high efficiency and precise output voltage control is possible. We carry out simulations and experiments to verify the validity.

• Journal of the Korea Computer Industry Society
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• v.5 no.5
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• pp.761-770
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• 2004

The multicarrier direct sequence code-division (MC-DS/CDMA) is a well-known multiple access and data transmission scheme that is applicable for various mobile and wireless communications. Particularly for modern, smart vehicles equipped with multiple sensors, MC-DS/CDMA is one of the possible means for giving the sensors to get connected one another for sending and receiving messages and control information. For intra-vehicalur communicaiton and networking applications, we have proposed a novel MC-DS/CDMA multiple access and data transmission scheme incorporating a new idea of inserting sub-symbol based cyclic prefixes for compromising inter-symbol interference. In the performance investigation of our MC-DS/CDMA, we have looked into system performances related to bandwidth utiltzation, coding gain, and multiple number of sensors. Since the channel delay is comparatively shorter inside of vehicle than any other general mobile channels, the proposed scheme can be a successful candidate for networking wireless sensors simultaneously operting in an intelligent vehicle.

• Journal of the Korea Computer Industry Society
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• v.2 no.12
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• pp.1541-1548
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• 2001

In this paper, We propose a new Kerberos certification mechanism that improve certification service based on PKINIT that announce in IETF CAT Working Group. Certification between area connected by chain through PKINIT that use X.509 and DS/DNS mutually for service. In order to provide regional services used private key and public key, X.509 of PKINIT is employed on session part and Kerberos's private key on actual authentication part. New mechanism be reduced communication overload doing to simplify certification formality between Client and remote KDC by KDC's certificate use to get ticket in remote sacred ground and remote KDC's reaffirmation process omitted.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2006.11a
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• pp.179-182
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• 2006

This project is for a Branch clinic of DS Skin Clinic who currently runs two other skin clinics in Daejeon Province. The major consideration of the project is to provide the high quality space appropriate for the unique medical services compared to any other skin clinics. The concept of the design is 'spaciousness of the past' and actual design elements used in this space is 'Frame', 'Smooth Traffic Pattern', 'Eye Flow', 'Faded looking finishes and colors of material' Overall space is divided into 2 areas, which are Dermatology Department providing medical service and Skin Clinic Department providing skin and body care. Those 2 areas are connected to each other through a circular reception area for administration, storage, and public area.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.28 no.3
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• pp.115-120
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• 2005

In this paper, we propose a personal-computer-based wireless data access system, which use DS/SS(Direct Sequence Spread Spectrum) method and the ISM band of 2.44GHz radio frequency. By applying hi-directional transmission between wireless handy terminals and PCs or servers, it can be easily connected with any kinds of database systems such as Oracle, MS-SQL and MS-ACCESS. Therefore, it could be economically adopted as peripheral equipments for ERP or SCM systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.539-542
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• 2005

In this paper, we propose a wireless data access system, which used direct sequence spread spectrum method and the ISM band with 900MHz radio frequency. By applying bi-directional transmission between wireless transmitter and receiver, it can be effectively connected with any kinds of RF-ID with 900MHz ISM band. Therefore it could economically be used as peripheral equipments for RF-ID system.

• Journal of Sensor Science and Technology
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• v.12 no.4
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• pp.149-155
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• 2003

A PMOSFET photodetector for highly-sensitive active pixel sensor(APS) is presented. This sensor uses 5V power supply and has been designed and fabricated using I-poly and 2-metal $1.5{\mu}m$ CMOS technology. The feature of a PMOSFET photodetector is that the polysilicon gate of the PMOSFET was connected to n-well, in order to increase the photo sensitivity. The designed MOS photodetector has similar $I_{DS}-V_{DS}$ characteristics with a standard MOSFET. One dimensional image sensor with 16 pixels based on the PMOSFET photodetector has also been designed and fabricated. Unit pixel of the designed sensor consists of a PMOSFET photodetector and 4 NMOSFETs. Unit pixel area is $86{\mu}m{\times}90.5{\mu}m$ and its fill factor is about 12%.

• Bulletin of the Korean Mathematical Society
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• v.41 no.2
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• pp.337-345
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• 2004

In allelic model X = ($\chi_1\chi$_2ㆍㆍㆍ, \chi_d$), M_f(t) = f(p(t)) - ${{\int^t}_0}\;Lf(p(t))ds$ is a P-martingale for diffusion operator L under the certain conditions. In this note, we can show existence and uniqueness of solution for stochastic differential equation and martingale problem associated with mean vector. Also, we examine that if the operator related to this martingale problem is connected with Markov processes under certain circumstance, then this operator must satisfy the maximum principle.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.4
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• pp.331-341
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• 2002

It is expected that the SCM (Subcarrier Multiplexing) optical link system, in which a number of small scale base stations with only antenna and RF transceiver are connected to central station through optical fiber, is in demand. In order to analyze the performance of SCM optical link system fur RF signal transmission, MZ(Mach-Zehnder) modulator's transfer function is modelled as nonlinear form with the cube of input signal. And considering the multiple access interferences occurred In the demodulation of other users'CDMA signals with multipath components after passing through MZ modulator, the BER performance is analyzed.