• Advances in environmental research
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• 제2권4호
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• pp.291-308
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• 2013

In the present study, an experimental design methodology was used to optimize the adsorptive removal of Basic Yellow 13 (BY13) using Turkish coal powder. A central composite design (CCD) consisting of 31 experiments was employed to evaluate the simple and combined effects of the four independent variables, initial dye concentration (mg/L), adsorbent dosage (g/L), temperature ($^{\circ}C$) and contact time (min) on the color removal (CR) efficiency (%) and optimizing the process response. Analysis of variance (ANOVA) showed a high coefficient of determination value ($R^2=0.947$) and satisfactory prediction of the polynomial regression model was derived. Results indicated that the CR efficiency was not significantly affected by temperature in the range of $12-60^{\circ}C$. While all other variables significantly influenced response. The highest CR (95.14%), estimated by multivariate experimental design, was found at the optimal experimental conditions of initial dye concentration 30 mg/L, adsorbent dosage 1.5 g/L, temperature $25^{\circ}C$ and contact time 10 min.

• 한국해양공학회지
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• 제36권5호
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• pp.295-302
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• 2022

The initial response to a marine accident can play a key role to minimize the accident. Therefore, various decision support systems have been developed using sensors, simulations, and active response equipment. In this study, we developed an algorithm to predict damage locations using ship motion data with bidirectional long short-term memory (BiLSTM), a type of recurrent neural network. To reflect the low frequency ship motion characteristics, 200 time-series data collected for 100 s were considered as input values. Heave, roll, and pitch were used as features for the prediction model. The F1-score of the BiLSTM model was 0.92; this was an improvement over the F1-score of 0.90 of a prior model. Furthermore, 53 of 75 locations of damage had an F1-score above 0.90. The model predicted the damage location with high accuracy, allowing for a quick initial response even if the ship did not have flood sensors. The model can be used as input data with high accuracy for a real-time progressive flooding simulator on board.

• Structural Engineering and Mechanics
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• 제88권5호
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• pp.405-417
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• 2023

This paper reveals theoretical research to the nonlinear dynamic response and initial geometric imperfections sensitivity of the spinning graphene platelets reinforced metal foams (GPLRMF) cylindrical shell under different boundary conditions in thermal environment. For the theoretical research, with the framework of von-Karman geometric nonlinearity, the GPLRMF cylindrical shell model which involves Coriolis acceleration and centrifugal acceleration caused by spinning motion is assumed to undergo large deformations. The coupled governing equations of motion are deduced using Euler-Lagrange principle and then solved by a combination of Galerkin's technique and modified Lindstedt Poincare (MLP) model. Furthermore, the impacts of a set of parameters including spinning velocity, initial geometric imperfections, temperature variation, weight fraction of GPLs, GPLs distribution pattern, porosity distribution pattern, porosity coefficient and external excitation amplitude on the nonlinear harmonic resonances of the spinning GPLRMF cylindrical shells are presented.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.23-27
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• 2007

Many trials have been used to model room impulse responses, all attempting to provide efficient representations of room acoustics. The traditional model designs for room impulse response seem to fail in accuracy, controllability, or computational efficiency. In time domain, a room impulse response is generally considered as the combination of three parts having different acoustic characteristics, initial time delay, early reflection, and late reverberation. This paper introduces new learning hybrid model for the room impulse response. In this proposed model, those three parts are modeled using different models with learning algorithms that determine the length or boundary of each model in the hybrid model. By the simulation with measured room impulse responses, it was examined that the performance of proposed model shows the best efficiency in views of both the parameter numbers and modeling error.

• International Journal of Control, Automation, and Systems
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• 제2권3호
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• pp.384-389
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• 2004

Recently a method of model reduction for discrete systems has been proposed in the literature based on a new impulse response Gramian. In this method, the system matrix$A_r$ of a reduced model is computed by approximating the reduced-order impulse response Gramian. The remaining matrices $b_r$ and $c_r$ are obtained so that various initial Markov parameters and time-moments of the original system are preserved in the reduced model. In this paper a different approach is presented based on the recursive relationship among the impulse response Gramians.

• Journal of information and communication convergence engineering
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• 제1권4호
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• pp.189-193
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• 2003

A new algorithm is presented for adaptive notch filtering of narrow band or sine signals for embedded among broad band noise. The notch filter is implemented as a constrained infinite impulse response filter with a minimal number of parameters, Based on the recursive prediction error (RPE) method, the algorithm has the advantages of the fast convergence, accurate results and initial estimate of filter coefficient and its covariance is revealed. A convergence criterion is also developed. By using the information of the noise-to-signal power, the algorithm can self-adjust its initial filter coefficient estimate and its covariance to ensure convergence.

• 한국환경과학회지
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• 제20권7호
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• pp.907-917
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• 2011

This study investigated the application of experimental design methodology to optimization of conditions of air-plasma and oxygen-plasma oxidation of N, N-Dimethyl-4-nitrosoaniline (RNO). The reactions of RNO degradation were described as a function of the parameters of voltage ($X_1$), gas flow rate ($X_2$) and initial RNO concentration ($X_3$) and modeled by the use of the central composite design. In pre-test, RNO degradation of the oxygen-plasma was higher than that of the air-plasma though low voltage and gas flow rate. The application of response surface methodology (RSM) yielded the following regression equation, which is an empirical relationship between the RNO removal efficiency and test variables in a coded unit: RNO removal efficiency (%) = $86.06\;+\;5.00X_1\;+\;14.19X_2\;-\;8.08X_3\;+\;3.63X_1X_2\;-\;7.66X_2^2$ (air-plasma); RNO removal efficiency (%) = $88.06\;+\;4.18X_1\;+\;2.25X_2\;-\;4.91X_3\;+\;2.35X_1X_3\;+\;2.66X_1^2\;+\;1.72X_3^2$ (oxygen-plasma). In analysis of the main effect, air flow rate and initial RNO concentration were most important factor on RNO degradation in air-plasma and oxygen-plasma, respectively. Optimized conditions under specified range were obtained for the highest desirability at voltage 152.37 V, 135.49 V voltage and 5.79 L/min, 2.82 L/min gas flow rate and 25.65 mg/L, 34.94 mg/L initial RNO concentration for air-plasma and oxygen-plasma, respectively.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.935-943
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• 2015

Permanent magnetic actuators (P.M.A.s) are widely used to drive medium-voltage-class vacuum circuit breakers (V.C.B.s). In this paper, a method for design optimization of a P.M.A. for V.C.B.s is discussed. An optimal design process employing the response surface method (R.S.M.) is proposed. In order to calculate electromagnetic and mechanical dynamic characteristics, an initial P.M.A. model is subjected to numerical analysis using finite element analysis (F.E.A.), which is validated by comparing the calculated dynamic characteristics of the initial P.M.A. model with no-load test results. Using tables of mixed orthogonal arrays and the R.S.M., the initial P.M.A. model is optimized to minimize the weight of the permanent magnet (P.M.) and to improve the dynamic characteristics. Finally, the dynamic characteristics of the optimally designed P.M.A. are compared to those of the initially designed P.M.A.

• 한국화재소방학회논문지
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• 제32권5호
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• pp.57-66
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• 2018

29명이 사망하고 40명이 부상을 입은 제천 스포츠센터 화재 사례에 대해 다수 사상자가 발생한 원인을 초기대응과 관리적인 측면을 중심으로 분석하였다. 초기대응 측면은 119신고 지연, 2층 세신사 비상구로 피난유도를 하지 않음, 1층과 3층 비상계단쪽 방화문 개방 상태 유지, 3층 주계단실 쪽 방화문 닫지 않음, 비상방송을 하지 않음으로 분석하였다. 관리적인 측면은 1층의 스프링클러설비 알람밸브 폐쇄, 소방펌프 제어반에서 기동 정지 위치에 놓음, 주차장 반자 안 누수 및 누전 방치, 2층 여탕의 휴게실 피난구유도등이 가려져 있고 비상구에 물건이 적치됨, 2층 자동문의 조작버튼 불량상태로 방치, 형식적인 소방안전관리, 소방시설 부실한 자체점검, 방화셔터와 배연창 미작동으로 분석하였다.

• 약학회지
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• 제26권4호
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• pp.239-251
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• 1982

The rate of deterioration of contractile force of isolated hearts from control and panax ginseng treated rats was determined and response of contractile force of the hearts from ginseng treated rats to several autonomic and other drugs was investigated. Rats weighing 150-250g were administrered orally with ginseng ethanol extract (100mg/kg) and total ginseng saponin (50mg/kg/day) for a week. Ginsenoside Rb$_{1}$ (5mg/kg/day) and ginsenoside Re (5mg/kg/day) were administered respectively for a week. The isolated hearts from rats were perfused with Krebs-Henseleit solution by using Langendorff perfusion apparatus. The control group was only able to maintain approximately 75.5% of their initial strength after 60 min of perfusion, whereas ginseng ethanol extract, total ginseng saponin treated hearts were able to sustain nearly their initial strength even after 60 min. Ginsenoside Rol treated hearts also sustained 93% of their initial strength, but there was no significant difference in the deterioration percentage of the contractile force of ginsenoside Re treated hearts. Experiments were conducted to study the response to perfusion of ginseng treated animal heart with epinephrine, isoproterenol, propranolol, and phenobarbital. The isolated hearts were perfused with Krebs-Henseleit solution containing epinephrine (10$^{-6}$ M), isoproterenol ($10^{-7}$M), propranolol ($10^{-6}$M) and phenobarbital (7{\times}10^{-3}M$) respectively. The maximum inotropic effect of epinephrine and isoproterenol was observed after 2~3 minutes of drug perfusion. Effect of epinephrine on ginseng ethanol extract and total ginseng saponin treated hearts was reduced compared with control. On the other hand, this phenomenon was not observed in ginsenoside Re treated rats but on ginsenoside $Rb_{1}$ treated rats. The positive inotropic effect of isoproterenol was reduced in the hearts from ginseng treated rats compared with control heart, Propranolol or phenobaribital decreased the contractile force in the control rats. The depressant effect of propranolol and phenobarbitat on ginseng treated rat hearts was less than those of control rat hearts. The result suggest that ginseng ethanol extract , ind total ginseng saponin and ginsenoside $Rb_{1}$ may protect the deterioration of contractile force of the heart and may attenuate the response to several drugs on hearts.