• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권4호
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• pp.575-594
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• 2010

In this study, we propose a space search algorithm (SSA) and then introduce a hybrid optimization of fuzzy inference systems based on SSA and information granulation (IG). In comparison with "conventional" evolutionary algorithms (such as PSO), SSA leads no.t only to better search performance to find global optimization but is also more computationally effective when dealing with the optimization of the fuzzy models. In the hybrid optimization of fuzzy inference system, SSA is exploited to carry out the parametric optimization of the fuzzy model as well as to realize its structural optimization. IG realized with the aid of C-Means clustering helps determine the initial values of the apex parameters of the membership function of fuzzy model. The overall hybrid identification of fuzzy inference systems comes in the form of two optimization mechanisms: structure identification (such as the number of input variables to be used, a specific subset of input variables, the number of membership functions, and polyno.mial type) and parameter identification (viz. the apexes of membership function). The structure identification is developed by SSA and C-Means while the parameter estimation is realized via SSA and a standard least square method. The evaluation of the performance of the proposed model was carried out by using four representative numerical examples such as No.n-linear function, gas furnace, NO.x emission process data, and Mackey-Glass time series. A comparative study of SSA and PSO demonstrates that SSA leads to improved performance both in terms of the quality of the model and the computing time required. The proposed model is also contrasted with the quality of some "conventional" fuzzy models already encountered in the literature.

• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2377-2386
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• 2021

To model the atmospheric dispersion of radionuclides released from nuclear accident is very important for nuclear emergency. But the uncertainty of model parameters, such as source term and meteorological data, may significantly affect the prediction accuracy. Data assimilation (DA) is usually used to improve the model prediction with the measurements. The paper proposed a parameter bias transformation method combined with Lagrangian puff model to perform DA. The method uses the transformation of coordinates to approximate the effect of parameters bias. The uncertainty of four model parameters is considered in the paper: release rate, wind speed, wind direction and plume height. And particle swarm optimization is used for searching the optimal parameters. Twin experiment and Kincaid experiment are used to evaluate the performance of the proposed method. The results show that the proposed method can effectively increase the reliability of model prediction and estimate the parameters. It has the advantage of clear concept and simple calculation. It will be useful for improving the result of atmospheric dispersion model at the early stage of nuclear emergency.

• Asian-Australasian Journal of Animal Sciences
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• 제27권8호
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• pp.1150-1156
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• 2014

This trail was conducted to study the effect of L-proline on the growth performance, and blood parameter in the weaned lipopolysaccharide (LPS)-challenged pigs. Thirty six pigs ($9.13{\pm}0.85$ kg) were assigned randomly to dietary treatments in a $2{\times}3$ factorial arrangement in a 20-d growth assay. Factors were intraperitoneal injection with saline or LPS, and three dietary L-proline supplement levels (0%, 0.5%, or 1.0%). On d 10, blood samples were collected at 3 h after LPS (100 ${\mu}g$ LPS/kg body weight [BW]) or saline injection. On d 20 of the trial, all pigs were orally administrated D-xylose (0.1 g/kg BW) at 2 h, and blood samples were collected at 3 h after LPS or saline injection. As a result, dietary supplementation with 0.5% proline had a tendency to increase average daily gain (ADG) in piglets during d 10 to 20 (p = 0.088). Without LPS challenge, dietary supplementation with 1.0% proline had no effect on growth hormone (GH) concentrations on d 10 (p>0.05), but decreased it after LPS challenge (p<0.05). There was LPS challenge${\times}$proline interaction for GH concentrations on d 10 (p<0.05). Dietary supplementation with 1.0% proline decreased glucagon concentration on d 10 after LPS challenge (p<0.05). In addition, dietary supplementation with proline increased superoxide dismutase (SOD) activity significantly on d 10 and 20 (p<0.05), and 1.0% proline increased heat shock proteins-70 concentration on d 10 (p<0.05). Moreover, proline supplementation increased diamine oxidase (DAO) concentrations after LPS challenge (p<0.05). There was LPS challenge${\times}$proline interaction for DAO (p<0.05). Furthermore, dietary supplementation with 1.0% proline increased the D-xylose level when no LPS challenge (p<0.05). These results indicate that proline supplementation could improve growth performance, increase SOD activities, and has a positive effect on the gastrointestinal tract digestibility in early weaned pigs.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.408-416
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• 2002

Hydraulic performance of the pump with an inducer was predicted by 3-D Navier-stokes calculation. The evaluated pump was the single-stage centrifugal pump with a separated inducer to pressurize fuel (LCH4) in Turbo-pump system with a specific speed (Ns) of approximately 0.3[rad/s, m3/s, J/kg] and a suction specific speed(s) of 15[rad/s, m3/s, J/kg]. That conventional pump was designed with the combination of 1-D theory and empirical correlation. In this study, preliminary design to select key parameters such as inlet flow coefficient was reviewed by investigating sets of the known design methods to achieve appropriate suction performance, and the performance of newly designed inducer and impeller was compared with the old one, using CFD method. The numerical results showed that the hydraulic efficiency of the new pump was predicted $5.5\%$ higher than that of the conventional one, through design parameter re-selection, configuration improvement and blade loading control

• 한국군사과학기술학회지
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• 제13권4호
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• pp.612-618
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• 2010

In order to successfully manage of the state-of-the-art weapon system R&D program which are under the limited budget and schedule but also has a high level of technical risks, it is gaining weights to use such a scientific program management tool as TPM. Therefore, the purpose of this research is to review the concept of the TPM and its relation among MOE, MOP and TPM, and introduce an application method of TPM mainly focusing on helicopter development program. It has the organized structure, detailed procedure and 282 parameters for performance management through the TPM.

• 전자공학회지
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• 제42권7호
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• pp.45-53
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• 2015

Power 소자 기술은 digital & mixed signal device와 on-chip 구현을 위해서 CMOS 공정에 대한 기본 이해가 필요하다. CMOS 공정 기반 위에 power device 공정을 추가하면서 다양한 operation voltage의 power 소자를 구현하고, passive device 들을 동일 공정에서 구현하여 다양한 components 들로 power IC 제품을 design 할 수 있도록 modular process를 제공하는 것이 중요하다. 또한 power device로 주로 사용되는 LDMOS 소자에 대한 performance 개선을 위해 simulation을 통해 key device parameter들의 특성을 예측하고, 구조를 설계하는 것이 Si process 전에 중요한 일 중의 하나이다. 아울러 power management가 potable power, consumer electronics 및 green energy에서 가장 빠르게 성장하는 분야이므로, 차별화된 power 소자 기술을 확보하여 급변하는 시장 환경에 대응하는 것이 필요하다.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.30-40
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• 2015

For a shunt power quality controller (SPQC) the DC side voltage value which is closely related to the compensation performance is a significant parameter. Buy so far, very little discussion has been conducted on this in a quantitative manner by previous publications. In this paper, a method to design the DC side voltage of SPQC is presented according to the compensation performance in the single-phase system and the three-phase system respectively. First, for the reactive current and the harmonic current compensation, a required minimal value of the DC side voltage with a zero total harmonic distortion (THD) of the source current and a unit power factor is obtained for a typical load, through the equivalent circuit analysis and the Fourier Transform analytical expressions. Second, when the DC side voltage of SPQC is lower than the above-obtained minimal value, the quantitative relationship between the DC side voltage and the THD after compensation is also elaborated using the curve diagram. Hardware experimental results verify the design method.

• Asian-Australasian Journal of Animal Sciences
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• 제26권4호
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• pp.579-587
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• 2013

A total of 288 crossbred (Duroc${\times}$Landrace${\times}$Yorkshire) growing pigs were used in two experiments to investigate the effects of adding ${\beta}$-mannanase to corn-soybean meal-based diets on pig performance and apparent total tract digestibility (ATTD). Both experiments lasted 28 d and were split into two phases namely 1 to 14 days (phase 1) and 15 to 28 days (phase 2). In Exp. 1,144 pigs weighing $23.60{\pm}1.59$ kg BW were assigned to one of four corn-soybean meal-based diets containing 0, 200, 400 or 600 U/kg ${\beta}$-mannanase. Increasing the level of ${\beta}$-mannanase increased weight gain (quadratic effect; p<0.01) and feed efficiency (linear and quadratic effect; p<0.01) during the second phase and the overall experiment. However, performance was unaffected (p>0.05) by treatment during phase 1. Increasing the amount of ${\beta}$-mannanase in the diet improved (linear and quadratic effect; p<0.05) the ATTD of CP, NDF, ADF, calcium, and phosphorus during both phases. Based on the results of Exp. 1, the optimal supplementation level was determined to be 400 U/kg and this was the level that was applied in Exp. 2. In Exp. 2, 144 pigs weighing $23.50{\pm}1.86$ kg BW were fed diets containing 0 or 400 U/kg of ${\beta}$-mannanase and 3,250 or 3,400 kcal/kg digestible energy (DE) in a $2{\times}2$ factorial design. ${\beta}$-Mannanase supplementation increased (p<0.01) weight gain and feed efficiency while the higher energy content increased (p<0.01) feed intake and feed efficiency during both phases and overall. Increased energy content and ${\beta}$-mannanase supplementation both increased (p<0.05) the ATTD of DM, CP, NDF, ADF, phosphorus, and GE during both phases. There were no significant interactions between energy level and ${\beta}$-mannanase for any performance or digestibility parameter. In conclusion, the ${\beta}$-mannanase used in the present experiment improved the performance of growing pigs fed diets based on corn and soybean. The mechanism through which the improvements were obtained appears to be related to improvements in ATTD.

• International Journal of Aeronautical and Space Sciences
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• 제18권3호
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• pp.535-544
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• 2017

In-flight aircraft engine performance estimation is one of the key techniques for advanced intelligent engine control and in-flight fault detection, isolation and accommodation. This paper detailed the current performance degradation estimation methods, and an improved hybrid Kalman filter via velocity-based LPV (VLPV) framework for these needs is proposed in this paper. Composed of a nonlinear on-board model (NOBM) and VLPV, the filter shows a hybrid architecture. The outputs of NOBM are used for the baseline of the VLPV Kalman filter, while the system performance degradation factors on-line estimated by the measured real system output deviations are fed back to the NOBM for its updating. In addition, the setting of the process and measurement noise covariance matrices' values are also discussed. By applying it to a commercial turbofan engine, simulation results show the efficiency.

• Smart Structures and Systems
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• 제26권6호
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• pp.693-701
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• 2020

The conventional Kalman Filter (KF) provides a promising way for structural state estimation. However, the physical parameters of structural systems or models should be available for the estimation. Moreover, it is not applicable when the loadings applied to the structures are unknown. To circumvent the aforementioned limitations, a two-stage KF with unknown input approach is proposed for the simultaneous identification of structural parameters and unknown loadings. In stage 1, a modified observation equation is employed. The structural state vector is estimated by KF on the basis of structural parameters identified at the previous time-step. Then, the unknown input is identified by Least Squares Estimation (LSE). In stage 2, based on the concept of sensitivity matrix, the structural parameters are updated at the current time-step by using the estimated structural states obtained from stage 1. The effectiveness of the proposed approach is numerically validated via a five-story shearing model under random and earthquake excitations. Shaking table tests on a five-story structure are also employed to demonstrate the performance of the proposed approach. It is demonstrated from numerical and experimental results that the proposed approach can be used for the identification of parameters of structure and the external force applied to it with acceptable accuracy.