• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.2
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• pp.157-164
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• 2016

The paper studies a comparison analysis of semi-active control strategies for a Macpherson strut type suspension system consisting of MR(magneto-rheological) damper. As a first step, in order to formulate governing, a dynamic full model of a Macpherson strut is developed considering the kinematics. The nonlinear equation of motion of the strut is then linearized around the equilibrium point. A new adaptive moving sliding model controller is developed for fast response of the system. A newly proposed adaptive moving sliding mode control strategy is then compared with conventional sliding mode controller and skyhook controller. The comparison is made for two different types of road inputs; bump and random road profiles showing superior vibration control performance in time and frequency domains.

• International Commerce and Information Review
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• v.8 no.2
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• pp.141-162
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• 2006

This paper focuses on the phenomenon that international payment system is essential as reverse action of delivery or supply of digital goods in global transactions. In order to impose the customs duties on imported goods in global on-line transactions, the imposition of tariff by tracing the payment process when business transaction is occurring is recommended. The purpose of this study is to review the countermeasures for effective tariff imposition system by using the model of the main payment tools in global transactions. Some models reviewed in this paper are as follows : i) a model of withholding taxes at the source by the credit company ii) a model of self declaration by the importer iii)a model of registering by overseas company iv) a model of negotiating after the taxation at the export country This study is different from existing preceding research at the point of view of presenting 4 models and doing appraisal by each model. It should be done more in depth and various study on the model of the tariff imposition system about the models reviewed at this paper. Systematic and reasonable alternatives which are actually adoptable at the system should also be studied and examined carefully. Because it is required that tariff imposition system on the digital goods should be harmonized with that of traditional business in order to obtain effectiveness and rightfulness, and especially, in order to get justness for the imposition a tariff on digital goods, the process of tax imposition should be predictable and be sure to get the fairness by enhancing the equilibrium, impartiality and transparency.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.837-844
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• 2017

The weir to regulate water level in a tide generation tank is above and below carried by two electric cylinders which are mounted on right and left of weir itself. In this case, a movement difference between right and left cylinder causes unbalance of weir and friction between weir and guide. And then, the weir will not be sent to target point. In this study, a synchronous control system is developed to take accurate and quick equilibrium of the weir. The control system based on cross coupled structure consists of two I-PD controllers and a lead compensator. Each of the I-PD controllers is designed in order that the electric cylinder may exactly follow the reference signal without overshoot and input saturation. And the lead compensator is designed to achieve stable and accurate synchronization. Finally, the simulation result shows that the designed synchronous control system is effective for elimination of synchronous error.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.659-664
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• 1994

Waxy rice, Oryza sativa, and foxtail millet, Setaria italitica, and mixture (1 : 1, w/w) of the cereals were saccharified by barley malt. The optimum conditions of saccharification were at $50^{\circ}C$ for 3 hrs on waxy rice and $55^{\circ}C$for 3 hrs on foxtail millet, respectively. The equilibrium of saccharification were reached at $20^{\circ}Brix$ on waxy rice and mixture, and $17^{\circ}Brix$ in foxtail millet. The free sugars in saccharifying liquids were found maltose, glucose and fructose with the contents of ca. 13%, 1% and trace, respectively, by HPLC analysis. The close relationships (r=0.954) between $^{\circ}{Brix}$ and reducing sugar of saccharifying liquids were observed. The result may be useful for the estimation of the end point of the saccharification.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.30.1-30.1
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• 2011

Silicon is one of useful materials in various industry such as semiconductor, solar cell, and secondary battery. The metallic silicon produces generally melting process for ingot type or chemical vapor deposition (CVD) for thin film type. However, these methods have disadvantages of high cost, complicated process, and consumption of much energy. Electrodeposition has been known as a powerful synthesis method for obtaining metallic species by relatively simple operation with current and voltage control. Unfortunately, the electrodeposition of the silicon is impossible in aqueous electrolyte solution due to its low oxidation-reduction equilibrium potential. Ionic liquids are simply defined as ionic melts with a melting point below $100^{\circ}C$. Characteristics of the ionic liquids are high ionic conductivities, low vapour pressures, chemical stability, and wide electrochemical windows. The ionic liquids enable the electrochemically active elements, such as silicon, titanium, and aluminum, to be reduced to their metallic states without vigorous hydrogen gas evolution. In this study, the electrodeposion of silicon has been investigated in ionic liquid of 1-butyl-3-methylpyrolidinium bis (trifluoromethylsulfonyl) imide ([bmpy]$Tf_2N$) saturated with $SiCl_4$ at room temperature. Also, the effect of electrode materials on the electrodeposition and morphological characteristics of the silicon electrodeposited were analyzed The silicon electrodeposited on gold substrate was composed of the metallic Si with single crystalline size between 100~200nm. The silicon content by XPS analysis was detected in 31.3 wt% and the others were oxygen, gold, and carbon. The oxygen was detected much in edge area of th electrode due to $SiO_2$ from a partial oxidation of the metallic Si.

• Journal of the Korean Institute of Gas
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• v.14 no.5
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• pp.32-37
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• 2010

In this study, vapor-liquid equilibrium (VLE) data at several isothermal temperatures for carbon dioxide and ethane binary systems were estimated using binary interaction parameters (BIP's) in Peng-Robinson (PR) equation of state built-in PRO/II with PROVISION (PRO/II) process simulator. Moreover, BIP's in PR equation of state were newly determined by regressing the experimental VLE data for carbon dioxide and ethane systems for each different isothermal temperatures using the summation of squares of the bubble point deviations as an objective function. Comparative works have been performed for absolute average deviation % (AAD(%)) between experimental and predicted bubble pressures using built-in BIP's in PRO/II and newly regressed one, respectively. Our calculation results gave a better estimation result than the simulation result using an existing parameter built-in PRO/II.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.5
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• pp.217-225
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• 2005

In a power system, an out-of-step condition causes a variety of risk such as serious damage to system elements, tripping of loads and generators, mal-operation of relays, etc. Therefore, it is very important to detect the out-of-step condition and take a proper measure. Several out-of-step detection methods have been employed in relays until now. Most common method used for an out-of-step detection is based on the transition time through the blocking impedance area in R-X diagram. Also, the R-R dot out-of-step relay, the out-of-step prediction method and the adaptive out-of-step relay using the equal area criterion (EAC) and Global Positioning Satellite (GPS) technology have been developed. This paper presents the out-of-step detection algorithm using the time variation of the complex power. The complex power is calculated and the mechanical power of the generator is estimated by using the electrical power, and then the out-of-step detection algorithm which is based on the complex power and the estimated mechanical power, is presented. This algorithm may detect the instant when the generator angle passes the Unstable Equilibrium Point (UEP). The proposed out-of-step algorithm is verified and tested by using Alternative Transient Program/Electromagnetic Transient Program (ATP/EMTP) MODELS.

• Environmental Engineering Research
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• v.14 no.3
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• pp.186-194
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• 2009

Understanding the environmental fate of human and animal pharmaceuticals and their risk assessment are of great importance due to their growing environmental concerns. Although there are many potential pathways for them to reach the environment, effluents from sewage treatment plants (STPs) are recognized as major point sources. In this study, the removal efficiencies of the 43 selected priority pharmaceuticals in a conventional STP were evaluated using two simple models: an equilibrium partitioning model (EPM) and STPWIN$^{TM}$ program developed by US EPA. It was expected that many pharmaceuticals are not likely to be removed by conventional activated sludge processes because of their relatively low sorption potential to suspended sludge and low biodegradability. Only a few pharmaceuticals were predicted to be easily removed by sorption or biodegradation, and hence a conventional STP may not protect the environment from the release of unwanted pharmaceuticals. However, the prediction made in this study strongly relies on sorption coefficient to suspended sludge and biodegradation half-lives, which may vary significantly depending on models. Removal efficiencies predicted using the EPM were typically higher than those predicted by STPWIN for many hydrophilic pharmaceuticals due to the difference in prediction method for sorption coefficients. Comparison with experimental organic carbon-water partition coefficients ($K_{ocs}) revealed that log KOW-based estimation used in STPWIN is likely to underestimate sorption coefficients, thus resulting low removal efficiency by sorption. Predicted values by the EPM were consistent with limited experimental data although this model does not include biodegradation processes, implying that this simple model can be very useful with reliable Koc values. Because there are not many experimental data available for priority pharmaceuticals to evaluate the model performance, it should be important to obtain reliable experimental data including sorption coefficients and biodegradation rate constants for the prediction of the fate of the selected pharmaceuticals.

• Journal of KIISE:Software and Applications
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• v.27 no.4
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• pp.422-431
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• 2000

This paper proposes a new codebook generation method, called a PCA-Based VQ, that incorporates the PCA (Principal Component Analysis) technique into VQ (Vector Quantization) codebook design. The PCA technique reduces the data dimensions by transforming input image vectors into the feature vectors. The cluster of feature vectors in the transformed domain is bisectioned into two subclusters by an optimally chosen partitioning hyperplane. We expedite the searching of the optimal partitioning hyperplane that is the most time consuming process by considering that (1) the optimal partitioning hyperplane is perpendicular to the first principal axis of the feature vectors, (2) it is located on the equilibrium point of the left and right cluster's distortions, and (3) the left and right cluster's distortions can be adjusted incrementally. This principal axis bisectioning is successively performed on the cluster whose difference of distortion between before and after bisection is the maximum among the existing clusters until the total distortion of clusters becomes as small as the desired level. Simulation results show that the proposed PCA-based VQ method is promising because its reconstruction performance is as good as that of the SOFM (Self-Organizing Feature Maps) method and its codebook generation is as fast as that of the K-means method.

• Journal of Advanced Navigation Technology
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• v.18 no.3
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• pp.254-260
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• 2014

We studied water level rising of drum versus time in the small hydraulic vertical water turbine system in this paper. The water level rises continuously up to a certain point with the passage of time if the constant incoming water is supplied, while it stops rising and maintains equilibrium state without any more rising because it increases position energy and evatually makes outgoing velocity and outgoing water quantities of runner area. The water level of drum is determined independent of size, height, width, figure of drum or runner configuration. It comes out that the water level is dependent only on the incoming and outgoing water quantities, and the output power has similar behavior. Therefore, desirable water level and output power are not available unless incoming water quantities is abundant. We validate this phenomina through applyng our methodolgies to the real small hydraulic vertical water turbine system under constructing and testing in industrial facilities in Korea.