• Journal of Institute of Control, Robotics and Systems
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• v.16 no.9
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• pp.827-832
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• 2010

Many researchers have tried to detect the falling and to reduce the injury associated with falling. Normally the method of detection of a loss of balance is more efficient than that of a compensatory motion in order to predict the falling. The detection algorithm of the loss of balance was composed of three main parts: parts of processing of measured data, construction of an internal model and detection of the loss of balance. The internal model represented a simple dynamic motion balancing with two rear legs of a four-legged chair and was a simplified model of a central nervous system of a person. The internal model was defined by the experimental data obtained within a fixed time interval, and was applied to the detecting algorithm to the end of the experiment without being changed. The balancing motion controlled by the human brain was improved in process of time because of the experience accruing to the brain from controlling sensory organs. In this study a reconstruction method of the internal model was used in order to improve the success rate and the detecting time of the algorithm and was changed with time the same as the brain did. When using the reconstruction method, the success rate and the detecting time were 95 % and 0.729 sec, respectively and those results were improved by about 7.6 % and 0.25 sec in comparison to the results of the paper of Ahmed and Ashton-Miller. The results showed that the proposed reconstruction method of the internal model was efficient to improve the detecting performance of the algorithm.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.758-771
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• 2021

This paper presents a novel control scheme for the three-dimensional (3D) path following of underactuated Autonomous Underwater Vehicle (AUVs) subject to unknown internal and external disturbances, in term of the time scale decomposition method. As illustration, two-time scale motions are first artificially forced into the closed-loop control system, by appropriately selecting the control gain of the integrator. Using the singular perturbation theory, the integrator is considered as a fast dynamical control law that designed to shape the space configuration of fast variable. And then the stabilizing controller is designed in the reduced model independently, based on the time scale decomposition method, leading to a relatively simple control law. The stability of the resultant closed-loop system is demonstrated by constructing a composite Lyapunov function. Finally, simulation results are provided to prove the efficacy of the proposed controller for path following of underactuated AUVs under internal and external disturbances.

• Journal of Digital Convergence
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• v.19 no.2
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• pp.51-60
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• 2021

In this study, Based on the analysis of the correlation between internal control quality and earnings management, this article discusses the correlation between internal control quality and real activity earnings management and accrued earnings management. For this study, by introducing the concept, classification, measurement method and model of internal control and earnings management, the research hypothesis of this article was proposed. In this analysis, Use the relevant measurement model to calculate the actual activity earnings management level and accrued earnings management level of the enterprise, as the explained variable, establish a model for regression and were analyzed. Also, this study could find the final results draws a conclusion through empirical research: there is a significant negative correlation between the internal control quality of listed companies, real activity earnings management, and accrued earnings management. On the basis of this conclusion, the analysis of possible causes provides a basis for the development of internal control theory and the supervision and control of earnings management behavior in the future.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.1
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• pp.82-89
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• 2003

A robust motion control method is proposed fur the point-to-point position control of a XY positioning system which consists of a base cart, elastic ben and moving mass. The horizontal motion controller consists of the feedforward controller to suppress the single mode vibration of the elastic beam and the feedback controller to get the high-accuracy positioning performance of the base cart. Input preshaping vibration suppression method based on system modeling with analytic frequency equation is proposed and integrated into the robust internal-loop compensator(RIC) to increase the robustness of the whole closed-loop system The vertical motion controller is proposed based on the dual RIC structure. Through experiments, it is shown that the proposed method can stabilize the system and suppress the vibration in the presence of uncertainties and disturbances.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.3
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• pp.236-241
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• 2003

This paper addresses the optimal design of dividing wall distillation column which is rapidly applied in a variety of chemical processes over recent several years because of its high energy saving efficiency. A general dividing wall column model which can cope with the heat transfer through the dividing wall is developed using rigorous computer simulation. Based on the simulation model, the effects of the internal recycle flow distribution around the dividing wall and the heat transfer across the dividing wall on overall system performance are investigated. An improved column design method is suggested to utilize the heat transfer through the wall. The suggested method is compared with the existing method via simulation study in which the proposed design shows improved energy saving result.

• Journal of Mechanical Science and Technology
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• v.19 no.8
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• pp.1554-1567
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• 2005

When multiple robotics systems with several sub-chains grasp a common object, the inherent force redundancy provides a chance of utilizing internal loading. Analysis of grasping space based internal loading is proposed in this work since this method facilitates understanding the physical meaning of internal loadings in some applications, as compared to usual operational space based approach. Investigation of the internal loading for a triple manipulator has been few as ,compared to a dual manipulator. In this paper, types of the internal loading for dual and triple manipulator systems are investigated by using the reduced row echelon method to analyze the null space of those systems. No internal loading condition is derived and several load distribution schemes are compared through simulation. Furthermore, it is shown that the proposed scheme based on grasping space is applicable to analysis of special cases such as three-fingered and three-legged robots having a point contact with the grasped object or ground.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.6
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• pp.450-456
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• 2000

In this paper, we proposed a novel control method which uses the internal impedance angles as a control parameter to drive traveling wave type ultrasonic motor. An impedance characteristic of the ultrasonic motor is obtained by analysis of the equivalent circuits including the external inductor used to generate the coupled resonance. The phase angle of internal impedance to achieve optimal control performance is derived. For the tracking of impedance angle, an information of phase difference is obtained from the applied voltage and current. The high speed phase difference detector is designed to monitor the phases of ultrasonic motor. The effectiveness of the proposed control scheme is clarified by experiments.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.3
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• pp.240-249
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• 2009

HRSG(Heat Recovery Steam Generator) building is large enclosed structure included various heat sources. This building needs to appropriately keep internal air temperature for worker's safety and operability of control devices. In this study, ventilation analysis is performed to find proper ventilation method for temperature control. Ventilation analysis is applied to entire internal space of the building with standard $k-{\varepsilon}$ model and enhanced wall treatment because of large size of the structure. And the ventilation method is considered natural and forced convection with two louver structures which has damper or not. Louver structure affect directly air circulation in near HRSG and lower region of the building. Forced ventilation provides strong inertial force which cause upward airflow. From the analysis, it is found that design requirement for internal air temperature can be satisfied by forced ventilation method with louver structure without damper.

• The Journal of Internal Korean Medicine
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• v.31 no.3
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• pp.526-538
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• 2010

Objective : This study was performed to investigate the effect of Sunhwangigagambang(SHG) on hyperlipidemia in SD rats induced by high cholesterol diet. Method : After treatment with SHG, cytotoxicity, body weight, liver weight, AST, ALT, ALP, total cholesterol, LDL-cholesterol, HDL-cholesterol, triglyceride, glucose, albumin, total protein in serum, malondialdehyde, and gene expression for ACAT and HMG-CoA reductase in hepatic tissue were analyzed. Result : 1. SHG didn't show any cytotoxicity in both human fibroblast cell line and SD rats. 2. SHG significantly inhibited the increase of liver weight by high cholesterol diet compared to the control group. 3. SHG significantly ameliorated the increase of total cholesterol, LDL-cholesterol, and triglyceride and reduction of HDL-cholesterol compared to the control group. 4. SHG significantly reduced glucose level in serum compared to the control group. 5. SHG significantly reduced malondialdehyde in hepatic tissue compared to the control group. 6. SHG significantly down-regulated gene expression of ACAT and HMG-CoA reductase compared to the control group. Conclusion : These results suggest that SHG might be effective in treatment and prevention of hyperlipidemia.

• The Korean Journal of Nuclear Medicine
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• v.16 no.2
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• pp.63-70
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• 1982

To evaluate the diagnostic usefulness and significance of quantitative sacroiliac joint scintigraphy in the assessment of sacroiliitis, we measured Sacroiliac Joint/Sacrum Uptake Ratio(SIS Ratio) by region of interest(ROI) method using $^{99m}Tc-methylene$ diphosphonate. The observed results were as follows: 1. Using ROI method, the SIS ratios for the control group of 65 persons were $1.05{\pm}0.08$(left) and $1.06{\pm}0.07$(right) which were narrower in range than those of slice method $(mean{\pm}S.D.)$. 2. The effects of age, gender and laterality on SIS ratio were not significant. 3. In left side, one of 6 patients with rheumatoid arthritis had SIS ratio in excess of 2 standard deviation of normal control group, and remainder had SIS ratios within normal limit. In right side, 3 patients had SIS ratios in excess of 2 standard deviation of normal control group, and remainder, within normal limit. 4. In both sacroiliac joint, 2 of 3 patients having sacroiliitis clinically with Reiter's syndrome whose pelvis A-P X-ray findings showed normal had high SIS ratios (left/right; 1.31/1.69, 1.90/1.80), but SIS ratio of one patient who had no evidence of sacroiliitis clinically was within normal limit. 5. In 6 patients with ankylosing spondylitis in both sacroiliac joints, 4 whose pelvis A-P Xray findings showed severe sclerotic change of sacroiliac joints had SIS ratio within normal limit or below that of normal control group, and SIS ratios of 2 patients whose pelvis A-P X-ray findings showed were increased. 6. 4 of 5 patients with low back pain of which cause could not be evaluated clinically and radiologically had SIS ratios in excess of that of normal control group. It would be concluded that quantitative sacroiliac joint scintigraphy is useful and sensitive screening method in the diagnosis as well as in the assessment clinical activity of sacroiliitis.