• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.9 no.4
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• pp.131-140
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• 2010

Recently, mobile wireless data traffic has been dramatically increased due to not only the popularization of digital convergence devices including smart phone, Net-book, and Tablet PC, but also the vitalization of wireless Internet related eco-systems such as AppStore. In addition, it is expected that a tremendous increase in mobile data is caused by the release of unlimited mobile data plans (flat-fee). In order to deal with such mobile data traffic explosion, it is necessary that network operators should make efforts to offload wireless data traffic. This paper reviews the condition of mobile wireless data traffic in domestic and international telecommunication industry and looks for various action plans to overcome the difficulty of network operators.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.259-262
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• 2009

본 연구에서는 석탄광산 선탄장설비와 국소배기시스템의 일부를 모형화하여 포집특성과 유동특성실험을 수행하였으며 동일조건에서 수치해석을 수행하여 그 결과를 비교 검토하였다. case 5가 46.35%의 가장 높은 포집효율을 보였으며 실험의 3가지 변수 중 고무 커튼의 사용유무가 국소배기시스템의 포집효율에 가장 큰 영향을 미치는 것으로 판단된다. 또한 case 1, 5, 6에 대해 포집된 입자크기 확인 결과, 포집성능이 우수한 case 5가 입경 $20{\mu}m$ 초과 입자들이 약 55%로 가장 많이 포집된 것을 알 수 있었다. 따라서 제어거리는 0.5m 이상이 적절한 것으로 판단된다.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.864-867
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• 1992

This paper describes optimum conditions for depositing Langumuir Blodgett(LB) films. $\pi$-A isotherm characteristics were studied with the following species, $C_{18}$-Quinolium(TCNQ), $C_{22}$-Quinolium(TCNQ), Azobenzene, Arachidic Acid, by varing length of alkyl chains, temperacture, pH, spreading amount, barrier moving speed and etc. We have observed the change of $\pi$-A isotherm depending on the above variations. From there we investigate the depositing conditions of LB films for each material.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.4
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• pp.357-364
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• 2017

Metal casting is a process in which molten metal or liquid metal is poured into a mold made of sand, metal, or ceramic. The mold contains a cavity of the desired shape to form geometrically complex parts. The casting process is used to create complex shapes that are difficult to make using conventional manufacturing practices. For the optimal casting process design of sleeve parts, various analyses were performed in this study using commercial finite element analysis software. The simulation was focused on the behaviors of molten metal during the mold filling and solidification stages for the precision and sand casting products. This study developed high-life sleeve parts for the sink roll of continuous hot-dip galvanizing equipment by applying a wear-resistant alloy casting process.

• Korean Journal of Pharmacognosy
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• v.31 no.1
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• pp.39-44
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• 2000

A sterol mixture, 3-O-glucosides of these sterols, 6'-O-fattyacyl ester of these sterol glucosides, kaempferol, quercetin and isoquercitrin were isolated from the whole plants of Hypericum ascyron L. The sterols were found to be a mixture of ${\beta}-sitosterol$, campesterol and stigmasterol by GC-MS. The kinds of fatty acids linked at 6'-OH of sterol glucoside ester mixture were shown to be palmitic acid, stearic acid, oleic acid and linoleic acid by GC-MS. Three flavonoids were identified by spectroscopic methods and comparisons of mixed mp and co-TLC with authentic specimens.

• Design & Manufacturing
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• v.8 no.2
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• pp.7-11
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• 2014

The Core-Shift is often generated on injection mold which have thin and long core. And Core-Shift brings out problems for thickness variation and product ejecting process. In this study, analysis of Core-Shift was performed according to change of materials of core(steel P-20, Be-Cu) and various polymers(PP, PC) by using MoldFolw MPI 6.1 which is commercial injection molding analysis program. As the results of analysis, the magnitude of Core-Shift was increased as being use polymer had lower fluidity and lower rigidity core. In the future, we will study the relationship between amount of Core-Shift and ejecting force.

• Proceedings of the KOSOMBE Conference
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• v.1990 no.05
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• pp.51-55
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• 1990

In this study, a peripheral auditory model used as a frequency feature extractor and a recurrent network which has recurrent links on input nodes is constructed in order to show the reliability of the recurrent network as a recognizer by executing recognition tests for 4 Korean placenames and syllables. As a result of this study, a refined weight compensation method is proposed and, using this method, it is possible to improve the system operation. The recurrent network in this study reflects well time information of temporal speech signal.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1395-1398
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• 2007

MgO thin films were deposited by e-beam evaporator using the 2-step method for alternate current plasma display panels (AC-PDPs). Glancing angle deposition (GLAD) method was employed to produce various surface geometry of the thin film; the bottom layer was deposited on a substrate by normal e-beam evaporation method and the top layer was deposited on bottom layer with $85^{\circ}$ by GLAD method. Results show that firing and sustain voltages improved as the sharpness of surface and isolated columnar structures increases, respectively.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1322-1325
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• 1987

In this study, the excitation pattern, which can be sensated by a man having hearing loss due to the damage of inner ear, is extracted, and the procedure of the auditory speech signal processing is simulated with the computer. Therefore, the excitation pattern is extracted by the neural tuning model satisfying the physiological characteristic of the inner ear and by the infor.ation extracted from speech signal. The firing pattern is also extracted by inputting this excitation pattern to the auditory neural model. With this extracted firing pattern, the possibility that the patient can sensate the speech signal is studied by the computer simulation.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.123-126
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• 2006

We propose a new-focusing method for test handlers of compact camera module (CCM), The MMD (max-min difference) method is applied to calculate the focus value quickly considering the noisy output of CCM. Also, the fuzzy search method is applied to find the maximum focus value effectively. We design a fuzzy processor to control the lens position by focus values and brightness values, which improves the focusing performance in the sense of speed and processor memory. The proposed method is implemented by program and installed at the CCM test handler machines. The simulation results are presented to verify the usefulness of the proposed method.