• The Journal of the Acoustical Society of Korea
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• v.24 no.8
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• pp.469-480
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• 2005

There have been always some difficulties in target setting and conditioning of acoustic performances or the Korean traditional music hall due mainly to the lack of the information on the sound radiation characteristics of Korean musical sources. As the 2nd experiment succeeding the previous study[1], the radiation characteristics of eight typical Korean traditional musical sources were investigated if precision. The selected musical sources were Geomungo, Haegeum (string), Piri, Taepyeongso (woodwind), Buk, Kwaengguari, Jing (drum), and male Pansori Chang (vocal Performance). The results show that the directivity pattern of each instrument is different and has their own directivity characteristics. Measured directional and spectral characteristics of traditional Korean music sources were implemented into the computation of architectural acoustic measures. Significant differences in the acoustic measures at receiver positions were observed between the results in using the omni-directional source and the directional one. In order to investigate the acoustical characteristics of the instruments depending on the spatial variation four different shapes of halls were introduced including rectangular, fan. horse-shoe and geometrical shapes. Room acoustical parameters such as RT, SPL, C80, LF, STI were calculated at each type or hall. As the results, It was found that the rectangular hall has the most high clarity. lateral energy and STI values among low shapes of halls. It is thought that the suggested source data and design method can be used as a basic reference in the future acoustic design of performance halls for the Korean traditional music.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1432-1435
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• 2006

We report on carbon nano-fibers (CNFs) for applying to epoxy as a highly thermal conductive adhesive. In order to fabricate CNFs, electro-spinning process was performed with polyacrylonitrile (PAN) solutions. The sample was stabilized at the annealing temperature of $360^{\circ}C$, and carbonized from 900 to $1100^{\circ}C$. It is shown that the synthesized CNFs have a good thermal conductivity of several hundred W/m K. LED backlight units (BLUs) fabricated with MPCB using CNF-mixed epoxy give a better heat dissipation and higher performance than normal LED BLUs. On the basis of SEM, XRD, and FTIR, the characteristics of CNFs are described.

• The Journal of Korea Robotics Society
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• v.3 no.2
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• pp.131-136
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• 2008

This paper proposes a method to extract the personal information using a microphone array. Useful personal information, particularly customers, is age and gender. On the basis of this information, service applications for robots can satisfy users by offering services adaptive to the special needs of specific user groups that may include adults and children as well as females and males. We applied Gaussian Mixture Model (GMM) as a classifier and Mel Frequency Cepstral coefficients (MFCCs) as a voice feature. The major aim of this paper is to discover the voice source parameters of age and gender and to classify these two characteristics simultaneously. For the ubiquitous environment, voices obtained by the selected channels in a microphone array are useful to reduce background noise.

• Journal of the Korean Geographical Society
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• v.37 no.1
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• pp.41-60
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• 2002

It has been ten years since Daily Living Information Newspapers are first circulated as an useful local information source for everyday life in Korea. The circulation region is formed by the population size according to each type and sometimes, everyday life space across the boundaries of metropolitan area or province. The Daily Living Information Newspapers published in the area where corporations are located are distinguished from the others by region-attached advertisements. And their circulation regions of them are more detailed.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.428-437
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• 2007

Along with the development of network, more and more functions and services are required by users, while traditional network fails to support all of them. Although overlay is a good solution to some demands, using them in an efficient, scalable way is still a problem. This paper puts forward a framework on how to construct an efficient, scalable overlay mesh in real network. Main differences between other overlays and ours are that our overlay mesh processes some nice features including class-of-service(CoS) and traffic engineering(TE). It embeds the end-to-end optimal traffic control law which can distribute traffic in an optimal way. Then, an example is given for better understanding the framework. Particularly, besides good scalability, and failure recovery, it possesses other characteristics such as routing simplicity, self-organization, etc. In such an overlay mesh, an applicable source routing scheme called hierarchical source routing is used to transmit data packet based on UDP protocol. Finally, a guideline derived from a number of simulations is proposed on how to set various parameters in this overlay mesh, which makes the overlay more efficient.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.3
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• pp.25-34
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• 2018

This paper presents a heating source of carbon nanofibers for the efficiency and the drying performance of laundry dryer, and focuses on the applicability-evaluation of its source. To design the proposed heating module, experiments were conducted in terms of surface temperature and surface temperature distribution characteristics of carbon nanofiber lamps. The surface temperature of the lamps increased linearly with increment of a current to flow a lamp and revealing the increasing pattern as the length of the ramps is shorter. The proposed heating source was evaluated based on drying efficiency, moisture evaporation rate at laundry, and internal temperature of a drum during drying process. The drying efficiency satisfied a 45% which is specified in KS C 9319. The moisture evaporation rate and the internal temperature of the drum were respectively 98.88% and $61.1^{\circ}C$, which are similar to that of S's company dryer. From the evaluation and actual drying test results, the proposed carbon nanofiber lamp heating module is considered to be applicable as a heat source for laundry dryer in terms of drying efficiency and drying performance. it is possible to obtain a heat source at a high temperature, an excellent calorific value, an improvement in drying performance, and an effect of sterilizing laundry due to the emission of far-infrared rays. In addition to the applicability, the difference of the drying efficiency between the dryers was analyzed in detail based on the power consumption of the heat sources.

• Journal of Satellite, Information and Communications
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• v.8 no.1
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• pp.45-53
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• 2013

An electrostatic discharge (ESD) protection device, so called, N-type extended drain silicon controlled rectifier (NEDSCR) device, was analyzed for high voltage I/O applications. A conventional NEDSCR device shows typical SCR-like characteristics with extremely low snapback holding voltage. This may cause latch-up problem during normal operation. However, a modified NEDSCR device with proper junction/channel engineering using counter pocket source (CPS) ion implantation demonstrates itself with both the excellent ESD protection performance and the high latch-up immunity. Since the CPS implant technique does not change avalanche breakdown voltage, this methodology does not reduce available operation voltage and is applicable regardless of the operation voltage.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1200-1203
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• 2002

A temperature compensated Crystal Oscillator is widely used for the stable frequency source of mobile communication equipments. Recently, it has become necessary to reduce power consumption of TCXOs. In this paper, we have proposed a TCXO using weak inversion MOS transistors and have evaluated its fundamental characteristics.

• Journal of the Korean Professional Engineers Association
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• v.41 no.2
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• pp.68-74
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• 2008

Asian Dust is a seasonal phenomenon which affects much of East Asia mostly in spring. The dust and sand storm originate in the deserts of Mongolia. northern China, and Kazakhstan. Asian Dust is carried eastward by prevailing winds, and pass over China, the Korean Peninsula. and Japan. In recent years, Republic of Korea, China, and Japan have participated in projects associated with implementation of observation network and reforestation in the source region. The information of Asian Dust can be exchanged in real time among the east Asian countries through the international co-operation.

• Journal of Electrical Engineering and information Science
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• v.1 no.2
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• pp.109-118
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• 1996

This paper deals with a new multi-level high voltage source inverter with GTO Thyristors. Recently, a multi-level approach seems to be the best suited for implementing high voltage conversion systems because it leads to harmonic reduction and deals with safe high power conversion systems independent of the dynamic switching characteristics of each power semiconductor device. A conventional multi-level inverter has some problems; voltage unbalance between DC-link capacitors and larger blocking voltage across the inner switching devices. To solve these problems, the novel multi-level inverter structure is proposed.