• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.2
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• pp.58-69
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• 1998

A contrp; suste, fpr SCARA robot is designed for implememting a robust dynamic control algorithm. this study forcuses on the use of DSPs in the design of joint controllers and interfaces in between the host cotroller and four joint controllers and in between the joint controllers and four servo drives. The mechanical body of SCARA robot and the servo drives are selected from the commercially available ones. The four joint controllers, assigned to each joint one by one, are combined into a common system through a mother board hardwarewise and through the global memeory softwarewise. The mother board is designed to connect joint controllers onto the board through the slots adopting PC/104 bus structures. And, the global memory stores the common data which can be shared by joint controllers and the host computer directly, which virtually combines the whole system into one. To demonstrate the performance and efficienty of the sytem, a robust inverse dynamic algorithm is proposed and implemented for a faster and more precise control. The robust inverse dynamic algorithm is basically derived from an inverse dynamci algorithm and a PID compensator. Based upon the derived dynamic equitions of SCARA robot, the inverse dynamic algorithm is intitially implemented within 0.3 msec of the control cycle in this system. The algoithm is found to be not accurate enough for the high speed and precision tasks due to inherent modelling errors and time-varying factors. Therefore, a variable PID algorithm is combined with the inverse dynamic algorithm to support robustness of control performance. Experimental datfor the proposed algorithm are presented and compared with the result obtained from PID and inverse dynamic algorithm.

• Journal of the Korea Convergence Society
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• v.6 no.3
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• pp.65-71
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• 2015

Based on Technology Threat Avoidance Theory, this study explains the process that the users cope with IT Threat and accomplish IS outcome. To empirically test the proposed model, data were collected through a survey of respondents who have the experience of using IS, and analyzed by using structural equations modelling. The result shows IT Threat had negative effects on Problem-Focused Coping and IS Appropriation. Also Problem-Focused Coping had significant effects on IS Appropriation and IS Appropriation had positive relation on IS Performance. In conclusion the study proposed that IT users improve Convergence Information System Performance by Problem-Focused Coping when they perceive IT Threat.

• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.111-120
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• 1999

Leachate flow behavior due to intermediate cover soil of low hydraulic conductivity and the applicability of pumping method for reducing the leachate level in the landfill are analyzed with the numerical flow model, MODFLOW. Using the hydraulic conductivity and storativity data obtained from the field pumping and slug tests(Jang and Cho, 1999), the hydraulic condition within the landfill is validated. The optimum rate of pumping, the radius of influence, and the efficiency of horizontal drain are analyzed for reducing the leachate level in the landfill. From the results of the analyses, the barrier effect that the buried cover soil of low hydraulic conductivity prevents the vertical movement of leachate flow through the cover soil, which is found from the in-situ geotechnical studies(Jang and Cho, 1999), is identified again. Also, the installation of horizontal drains to the pumping well can increase the pumping rate from 120 ton/day per a well to 300 ton/day. The length of horizontal drain did not influence significantly on the drawdown-time curve of leachate in the landfill.

• Journal of Venture Innovation
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• v.1 no.1
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• pp.113-127
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• 2018

The purpose of this study was to investigate the determinants of organizational trust and its effect on organizational effectiveness in the public organizations. This study examined five factors of organizational competencies, consideration, fairness, organizational morality and organizational social responsibility as the determinants of organizational trust and job satisfaction, organizational commitment and intend to leave as the indicators of organizational effectiveness. For this study, data were collected from 323 public officials in Gyeonggi Province with structured questionnaires and analyzed using structural equation modelling technique. This study found that organizational competencies, consideration, fairness, organizational morality and organizational social responsibility made significant contributions to the formation of organizational trust and that organizational trust impacted positively organizational effectiveness measured in terms of job satisfaction, organizational commitment and intend to leave.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.264-273
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• 2013

The importance of the robots has emerged as the means of minimizing the casualties in the future war, and, thus, the biomimetic robots mimicking the optimized organisms has been actively studied. The robot inspired lizard is suitable for reconnaissance and the surveillance in narrow areas. In this paper, we analyzed the locomotion of a lizard by motion capture system using the infrared markers. We attached 21 markers to the joints of the lizard. By considering the measured data, we analyzed the walking motion of the lizard which trots in a sprawled posture. Moreover, we proposed the 25 dof kinematic model which was able to reproduce the gait of the lizard faithfully. The model was verified by simulations.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.3
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• pp.192-197
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• 2005

The effects of macronutrients $(NO_3^-,\; NH_4^+\;and\;PO_4^{3-})$ on cell growth and triterpenoids production in Centella asiatica cell suspension cultures were analyzed using the Box­Behnken response surface model experimental design. In screening and optimization experiments, $PO_4^{3-}$ as a single factor significantly influenced cell growth where increasing the phosphate level from 0.1 to 2.4 or 2.6 mM, elevated cell growth from 3.9 to $14\~16g/L$. The optimum values predicted from the response surface model are 5.05mM $NH_4^+$, 15.0mM $NO_3^-$ and 2.6mM $PO_4^{3-}$, yielding 16.0g/L cell dry weight with $99\%$ fitness to the experimental data. While the $NH_4^+-NO_3^-$ interaction influenced cell growth positively in the optimization experiment, $NH_4^+$ and $NO_3^-$ as single factors; and interactions of $NO_3^--PO_4^{3-},\;NH_4^+-PO_4^{3-}$ and $NH_4^+-NO_3^-$ were all negative in the screening experiment. Cell growth and the final pH level were positively affected by $PO_4^{3-}$, but negatively affected by $NH_4^+\;and\;NH_4^+-PO_4^{3-}$ interactions. The different effects of factors and their interactions on cell growth and final pH are influenced by a broad or narrow range of macronutrient concentrations. The productions of triterpenoids however were lower than 4mg/g cell dry weight.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.4
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• pp.385-392
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• 2005

This paper describes an accuracy analysis of newly developed gravimetric geoid and an improvement of developed geoid using GPS/Levelling data. We developed the KGEOID05 model corrected with the correction term. The correction term is modelled using the difference between GPS/Levelling derived geoidal heights and gravimetric geoidal heights. The stochastic model used in the calculation of correction term is the least squares collocation technique based on second-order Markov covariance function. 373 GPS stations were used to model the correction term. The standard deviation of KGEOID05 is about 11 cm and it indicates that we can be determined accurate heights ($2{\sim}3\;cm$) when we made precise modelling using KGEOID05 and a few GPS measurements for the local area.

• The Korean Journal of Applied Statistics
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• v.19 no.3
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• pp.481-504
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• 2006

VaR, a tail-related risk measure is now widely used as a tool for a measurement and a management of financial risks. For more accurate measurement of VaR, recently we are particularly concerned about the approach based on extreme value theory rather than the traditional method based on the assumption of normal distribution. However, many studies about the approaches using extreme value theory was done only for the univariate case. In this paper, we discuss portfolio risk measurements with modelling multivariate extreme value distributions by combining copulas and extreme value theory. We also discuss the estimation of ES together with VaR as portfolio risk measures. Finally, we investigate the relative superiority of EVT-copula approach than variance-covariance method through the back-testing of an empirical data.

• Communications for Statistical Applications and Methods
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• v.15 no.6
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• pp.859-873
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• 2008

Job satisfaction impacts on the turnover intention of employee, which affects the turnover behavior. This paper concerns with the impact of job satisfaction on the turn over behavior. Since turnover intention is highly correlated with job satisfaction, salary, employment status and etc, we should pay careful attention for modelling of those variables as independent variables and the turnover behavior as a dependent variable in the empirical study for the impact of factors on turnover behavior. We detect significant variables which effect the turnover behavior using 2-stage logistic regression inserting the turnover intention, an independent variable, with the chance estimates derived from the instrumental variables in Graduates Occupational Mobility Survey.

• Journal of Korea Multimedia Society
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• v.13 no.4
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• pp.504-511
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• 2010

In this paper, we propose the face region recognition system for City-Security CCTV(Closed Circuit Television) using hippocampal neural network which is modelling of human brain's hippocampus. This system is composed of feature extraction, learning and recognition part. The feature extraction part is constructed using PCA(Principal Component Analysis) and LDA(Linear Discriminants Analysis). In the learning part, it can label the features of the image-data which are inputted according to the order of hippocampal neuron structure to reaction-pattern according to the adjustment of a good impression in a dentate gyrus and remove the noise through the auto-associative memory in the CA3 region. In the CA1 region receiving the information of the CA3, it can make long-term memory learned by neuron. Experiments confirm the each recognition rate, that are shape change and light change. The experimental results show that we can compare a feature extraction and learning method proposed in this paper of any other methods, and we can confirm that the proposed method is superior to existing methods.