• 한국토양비료학회지
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• 제48권5호
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• pp.413-420
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• 2015

Objective of this study was to investigate adsorption characteristics and kinetic models of $NH_4-N$ to biochar produced from rice hull in respective to mitigation of greenhouse gases. $NH_4-N$ concentration was analyzed by UV Spectrophotometer. For the experiment, the soil texture used in this study was sandy loam soil, and application rates of chemical fertilizer and pig compost were $420-200-370kgha^{-1}$ (N-P-K) and $5,500kgha^{-1}$ as recommended amount after soil test for corn cultivation. Biochar treatments were 0.2-5% to soil weight. Its adsorption characteristic was investigated with application of Langmuir isotherm, and pseudo-first order kinetic model and pseudo-second order kinetic model were used as kinetic models. Adsorption amount and removal rates of $NH_4-N$ were $39.3mg^{-1}$ and 28.0% in 0.2% biochar treatment, respectively. The sorption of $NH_4-N$ to biochar was fitted well by Langmiur model because it was observed that dimensionless constant ($R_L$) was 0.48. The maximum adsorption amount ($q_m$) and binding strength constant (b) were calculated as $4.1mgg^{-1}$ and $0.01Lmg^{-1}$ in Langmuir isotherm, respectively. The pseudo-second order kinetic model was more appropriate than pseudo-first order kinetic model for high correlation coefficient ($r^2$) of pseudo-second order kinetic model. Therefore, biochar produced from rice hull could reduce $N_2O$ by adsorbing $NH_4-N$ to biochar cooperated in sandy loam soil.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.927-931
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• 2003

In this paper, a new Recursive Least-Squares(RLS) algorithm based on matrix pseudo-inverses is presented. The aim is to use the proposed new RLS algorithm for not only the over-determined but also the under-determined estimation problem. Compared with previous results, e.g., Jie Zhou et al., the derivation of the proposed recursive form is much easier, and the recursion form is also much simpler. Furthermore, it is shown by simulations that the proposed RLS algorithm is more efficient and numerically stable than the existing algorithms.

• Smart Structures and Systems
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• 제25권1호
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• pp.47-56
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• 2020

This paper proposes a model-based approach for structural damage identification and quantification. Using pseudo modal strain energy and mode shape vectors, a damage-sensitive objective function is introduced which is suitable for damage estimation and quantification in shear frames. Whale optimization algorithm (WOA) is used to solve the problem and report the optimal solution as damage detection results. To illustrate the capability of the proposed method, a numerical example of a shear frame under different damage patterns is studied in both ideal and noisy cases. Furthermore, the performance of the WOA is compared with particle swarm optimization algorithm, as one the widely-used optimization techniques. The applicability of the method is also experimentally investigated by studying a six-story shear frame tested on a shake table. Based on the obtained results, the proposed method is able to assess the health of the shear building structures with high level of accuracy.

• 감성과학
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• 제15권4호
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• pp.441-452
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• 2012

최근 들어 청각 장애인들에게 정상인들이 소리로부터의 느끼는 청감과 유사한 느낌을 전달하기 위한 방안으로써 시각은 물론 진동감과 같은 촉감을 활용하는 연구가 시도되고 있다. 특히 시각 정보의 보조 감각으로써 스피커나 진동 모터를 이용한 촉감이 제공되는 경우 생동감은 상당히 개선되는 측면이 있으나 정서감 측면에서는 그 효과가 거의 없는 것으로 보고되었다. 따라서 본 연구에서는 유사 청감을 재현할 수 있는 또 하나의 보조 감각으로서 열감을 설정하고 열감이 유사 청감 재현 효과를 가질 수 있는가에 관하여 조사하였다. 이를 위해 열감을 효과적으로 재현할 수 있는 열감 재현 모듈을 구현하였다. 그리고 실험 대상자들에게 시각 정보와 더불어 청각 정보, 진동 촉감, 그리고 열감을 혼합한 다양한 형태의 자극을 제공한 실험을 수행하였다. 실험에서 얻어진 데이터 통계 분석을 통하여 i) 영상과 함께 열감 자극을 제공하거나 또는 ii) 영상과 함께 열감 자극과 진동 자극을 동시에 제공하는 경우가 영상만을 제공하는 경우보다 실험 대상자들이 영상과 소리로부터 느끼는 실제 열감에 더 가까운 유사 열감을 느낄 수 있다는 사실을 확인하였다. 결론적으로 실험 대상자의 피부에 제공되는 열감이 유사 청감 재현 보조 매체로서의 활용 가능성이 있음을 확인할 수 있었다.

• Applied Microscopy
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• 제29권1호
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• pp.95-103
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• 1999

Pseudo-brookite 구조의 $MgTi_2O_5$와 이와 유사한 구조를 갖는 $(In_{0.36}Zn_{1.09})Ti_2O_{5.64}$에 관한 미세구조를 200kV에서 작동되는 고분해능 투과전자현미경을 사용하여 관찰하였다. 변조구조는 $MgTi_2O_5$에서는 발견되지 않았으나, $(In_{0.36}Zn_{1.09})Ti_2O_{5.64}$에서는 복잡한 구조가 발견되었다. $(In_{0.36}Zn_{1.09})Ti_2O_{5.64}$ 구조의 전자회절패턴은 $MgTi_2O_5$와 fundamental 회절점들은 유사하나 4가지 형태의 초격자 회절점이 더 존재하였다. 변조구조의 주기는 [220] 방향으로 3.63nm, 0.79nm, 그러고 0.64 nm를 이루고 [420] 방향으로는 0.81nm를 이룬다. 미세구조 관찰중 전자빔에 의하여 상전이가 야기되어 변조된 구조에서 좀 더 단순화된 변조없는 구조로 가역적으로 전환한다. 가해지는 전자빔에 의한 손상기구는 ledge 구조의 kink에서 void가 형성되어 작은 결정들로 갈라지고 손상이 커지면, 최종적으로 결정성을 잃게 된다.

• Journal of Astronomy and Space Sciences
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• 제38권3호
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• pp.165-173
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• 2021

Apophis is a near-Earth object with a diameter of approximately 340 m, which will come closer to the Earth than a geostationary orbit in 2029, offering a unique opportunity for characterizing the object during the upcoming encounter. Therefore, Korea Astronomy and Space Science Institute has a plan to propose a space mission to explore the Apophis asteroid using scientific instruments such as a laser altimeter. In this study, we evaluate the performance metrics of a laser altimeter using a pseudorandom noise modulation technique for the Apophis mission, in terms of detection probability and ranging accuracy. The closed-form expression of detection probability is provided using the cross correlation between the received pulse trains and pseudo-random binary sequence. And the new ranging accuracy model using Gaussian error propagation is also derived by considering the sampling rate. The operation range is significantly limited by thermal noise rather than background noise, owing to not only the low power laser but also the avalanche photodiode in the analog mode operation. However, it is demonstrated from the numerical simulation that the laser altimeter can achieve the ranging performance required for a proximity operation mode, which employs commercially available components onboard CubeSat-scale satellites for optical communications.

• 인지과학
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• 제35권2호
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• pp.97-112
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• 2024

한글에서 글자는 단어를 구성하는 주요한 단위이다. 본 연구는 한글 글자의 속성(글자의 빈도, 모음의 유형, 받침의 유무, 글자의 위치)이 단어와 비단어의 명명에 영향을 미치는지를 알아보고자 하였다. 선형혼합 효과분석 결과 단어는 첫째 글자의 빈도가 증가할수록 명명시간이 감소하였으며, 첫째 글자에 받침이 있을 때 명명시간이 감소하였다. 또한, 단어가 횡모음 유형일 때보다 종모음 유형일 때 명명 정확률이 더 높았으며 첫째 글자에 받침이 없을 때보다 있을 때 명명시간이 감소하였다. 비단어는 첫째 글자의 빈도와 둘째 글자의 빈도가 각각 증가할수록 명명시간이 감소하였으며 명명 정확률이 더 높았다. 비단어도 횡모음 유형일 때보다 종모음 유형일 때 명명 정확률이 더 높았다. 본 연구에서 둘째 글자의 빈도 효과는 단어와 비단어에 따라 달랐지만, 첫째 글자의 빈도효과와 모음 유형의 효과는 일관되게 나타났다. 시각단어재인에 대해 연구 결과의 함의를 논의하였다.

• Journal of applied mathematics & informatics
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• 제5권2호
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• pp.475-488
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• 1998

Wolfe and Mond-Weir type duals for multiobjective con-trol problems are formulated. Under pseudo-invexity/quasi-invexity assumptions of the functions involved, weak and strong duality the-orems are proved to relate efficient solutions of the primal and dual problems.

• Environmental Engineering Research
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• 제25권4호
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• pp.479-487
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• 2020

Current assumptions are used in the formulation of pseudo-first (PFO) and second-order (PSO) models to describe the kinetic data of filtration based on ideal operating conditions. This paper presents a new model developed with pseudo n^th order and based on real assumption. A comparison was performed between PFO, PSO and the new model to highlight their performance and the optimisation of the pseudo-order equation, using MATLAB software. Adsorption characteristic of bovine serum albumin adsorption on the track-etched membrane are used as a medium based on protein filtration data were extracted from the literature for different concentrations to demonstrate the comparison between PFO/PSO and the new model. The pseudo first and second-order kinetic models were applied to test the experimental data and they did not provide reasonable values. The results show that the predicted values are consistent with experimental values giving a good correlation coefficient R² = 0.997 and a minimum root mean squared error RMSE = 0.0171. Indeed, the experimental results follow the new model and the optimal pseudo equation order n = 1.115, the most suitable curves for the new model. As a result, we used different experimental adsorption data from the literature to examine and check the applicability and validity of the model.

• Journal of Power Electronics
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• 제4권3호
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• pp.127-137
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• 2004

This paper introduces a hybrid induction motor control using a genetically optimized pseudo-on-line method. Optimization results from the use of a look-up table based on genetic algorithms to find the global optimum of an unconstrained optimization problem. The approach to induction motor control includes a pseudo-on-line procedure that optimally estimates parameters of a fuzzy PID (FPID) controller. The proposed hybrid genetic fuzzy PID (GFPID) controller is applied to speed control of a 3-phase induction motor and its computer simulation is carried out. Simulation results show that the proposed controller performs better than conventional FPID and PID controllers. The contribution of this paper is the introduction of a high performance hybrid form of induction motor control that makes on-line and real-time control of the drive system possible.