• 한국인터넷방송통신학회논문지
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• 제13권6호
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• pp.55-61
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• 2013

본 논문은 음성합성에서 사용되는 오디오 부호기/복호기 설계 및 구현을 기술한다. 설계된 회로는 원래 음성 샘플대신에 연속되는 음성 샘플의 차를 부호화하는 방식으로 압축율은 4:1 이다. FPGA를 이용해서 각각의 기능을 검증하고, $0.35{\mu}m$ 표준 CMOS 공정을 이용하여 칩으로 제작해서 성능을 측정하였다. 시스템 클럭 주파수는 16.384MHz를 사용한다. THD(Total Harmonic Distortion)+n은 주파수에 따라서 -40dB에서 -80dB 값을 지니고, 전력 소모는 전원 전압 3.3V에서 80mW로써, 고음질과 저전력 소모를 요구하는 모바일 응용에 적합하다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.74.1-74.1
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• 2011

As a demand for energy, many studies are increasing about energy resource. One of these resources is coal which reserves of underground. A lot of research to use coal is going on as method of IGCC (Integrated Gasification Combined Cycle). In addition, SNG(Substitute Natural Gas) and IGFC (Integrated Gasification Fuel Cell) are also being developed for fuel & electricity. This technology which uses synthesis gas after gasification is to produce electricity from the Fuel Cell. At this point, important thing is the components of synthesis gas. The main objective is to increase the proportion of methane and hydrogen in synthesis gas. The catalytic gasification is suitable to enhance the composition of methane and hydrogen. In this study, Exxon Predevelopment catalyst gasification study was served as a good reference and then catalytic gasification simulation process is conducting using Aspen Plus in this research. For this modelling, kinetic value should be calculated from Exxon's report which is used for modeling catalytic gasification. Catalytic gasification model was performed by following above method and was analyzed by thermodynamic method through simulation results.

• 한국통신학회논문지
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• 제21권3호
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• pp.612-621
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• 1996

In this paper, we propose the low sidelobe digital FIR doppler filter bank synthesis algorithm through the Gradient Descent method and it can be practially appliable to coherent pulse doppler radar signal processing. This algorithm shows the appropriate calculation of tap coefficients or zeros for FIR transversal fiter which has been employed in radar signal processor. The span of the filters in the filter bank be selected at the desired position the designer want to locate, and the lower sidelobe level that has equal ripple property is achieved than one for which the conventional weithtedwindow is used. Especially, when we implemented filter zeros as design parameters it is possible to make null filter gain at zero frequency intensionally that would be very efficient for the eliminatio of ground clutter. For the example of 10 tap filter synthesis, when filter coefficients or zeros are selected as design parameters the corresponding sidelobelevel is reducedto -70db or -100db respectively and it has good convergent characteristics to the desired sidelobe reference value. The accuracy ofapproach to the reference value and the speed of convergence that show the performance measure of this algorithm are tuned out with some superiority and the fact that the bandwidth of filter appears small with respect to one which is made by conventional weighted window method is convinced. Since the filter which is synthesized by this algorithm can remove the clutter without loss of target signal it strongly contributes performance improvement with which detection capability would be concerned.

• 대한화학회지
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• 제3권1호
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• pp.18-22
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• 1954

The cation exchange resins are synthesized from p-phenolsulfonic acid, formalin, and sodium hydroxide catalyser, and the ion exchange properties of them are studied with respect to their reactant ratios. Maximum exchange capacity was 2.06 me/G, much smaller than the theoretical value of 3.42 me/G to be expected for that of the structure: Under the present experimental conditions, much -SO3H radical should have been split away.

• 한국세라믹학회지
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• 제21권1호
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• pp.5-10
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• 1984

$eta$-Sialon synthesis was investigated via the simulataneous reduction and nitriding of Wando pyrophyllite. When Wando pyrophyllite-graphite-$Si_3N_4$ seed mixture was heated at 135$0^{\circ}C$ for as long as 10 hours in 80% $N_2$-20%$H_2$ atomsphere $eta$-$Si_3N_4$ solid solution was mainly formed together with a small amount of $\alpha$-$Si_3N_4$ The value z of the forming $Si_{6-x}Al_2O_2N{8-z}$ was decreased with heating time.

• Journal of Microbiology and Biotechnology
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• 제8권3호
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• pp.287-290
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• 1998

Acarbose effectively inhibited the synthesis of dextran, and the inhibition pattern was a noncompetitive type with a $K_i$ value of 1.35 mM. It also inhibited the disproportionation reaction of dextransucrase with isomaltotriose and decreased the efficiency of the maltose acceptor reaction. Increased concentration of dextransucrase or maltose in reaction digests, however, decreased the degree of inhibition by acarbose.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.621-624
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• 2007

As a new fluoranthene derivative, a synthesis of benzo[k]fluoranthene was suggested, so new blue emitting materials, 7,12-diphenylbenzo[k] fluoranthene [DPBF] and 7,8,10- triphenylfluoranthene [TPF] were synthesized. $EL_{max}$ wavelength of the device using DPBF as an emitting layer was 436 and 454nm in the deepblue region, which are similar values with PL. The device that used DPBF as an emitting layer showed high efficiency of 2.11cd/A and the excellent color coordinate value of (0.161, 0.131) in deep-blue region.

• 한국세라믹학회지
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• 제32권1호
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• pp.71-82
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• 1995

The weathered two-mica granite is widely distributed in Korea and called a kind of ground rock for kaolin. The major minerla compositions are consist of this quartz, feldspar, mica and clay mineral. At present, only a small portion of this granite is used as the material for the low-grade tile industry due to the low S.K. value and the high contents of impurities such as Fe2O3 and FeO. The low S.K. value is caused by feldspars not weathered to clay minerals. The refinement of this thus has been required for the recent shortage of the resources of high-grade one. This paper concerns an optimum hydrothermal treatment condition to refine the low-grade weathered two-mica granite of which impurities are feldspar mineral and Fe2O3. FeO components in using for the main material of ceramic industry. And then, from this result, we tried to fine out the basic formation mechanism of clay mineral from feldspar etc and develope the effectual utilization method of this.

• 한국CDE학회지
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• 제21권2호
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• pp.31-33
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• 2015

This paper deals with synthesis of 4 bar linkage by using optimum design. To design 4 bar linkage, overlay method is proposed and for optimization, genetic algorithm is applied with objective function. The accuracy of this method will be determined by errors between real value and test value. We will use Chebychev spacing to get 3 precision positions of input angles. The output angles will be determined by the function that the designer wants input and output relations to be. It will be applied to example to show the accuracy of this method. The advantages of using this method are that it is fast to get optimal solution and it is simple to use.

• 제어로봇시스템학회논문지
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• 제16권1호
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• pp.77-82
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• 2010

An analytical method for robust design of the multi-loop proportional-integral (PI) controller is proposed for various types of multi-delay processes. On the basis of the direct synthesis and generalized IMC-PID approach, the analytical tuning rules of the multi-loop PI controller are firstly derived for achieving the desired closed-loop response, and the structured singular value synthesis is then utilized for the tradeoffs between the robust stability and performance by adjusting only one design parameter (i.e., the closed-loop time constant). To verify the superiority of the proposed method, the simulation studies have been conducted on a wide variety of multivariable processes. The multi-loop PI controller designed by the proposed method shows a fast, well-balanced and robust response with the minimum integral absolute error (IAE) in compared with other renowned methods.