• Journal of the Institute of Convergence Signal Processing
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• v.2 no.2
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• pp.103-110
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• 2001

To reduce the traffic congestion and parking problems in urban areas tall and narrow vehicles have interested as a means to increase the utilization of existing freeways and parking facilities. The stability problem for those narrow vehicles which might be caused can be reduced by tilting the body toward the inside of the turn. The Direct Tilt Control(DTC) system and the Steering Tilt Control(STC) system have been proposed for those narrow vehicles. In this paper, as one of the performance improvement for that kind of vehicle a new control system to use the merits of both the DTC system and the STC system is proposed. Because two different control systems fight each other, the switching control scheme is applied as a means to prevent fighting. Also, the method in order to achieve the smoothly changed control system when the system is switched from the DTC to the STC or from the STC to the DTC, the appropriate type of control gain is designed.

• YAKHAK HOEJI
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• v.46 no.6
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• pp.411-415
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• 2002

We compared the hypoglycemic effects of Ginseng Radix Alba (GRA) and Mori Folium (MF) in multiple low dose (MLD) streptozotocin(STZ)-induced diabetic rats. In order to induce hyperglycemic state 25 mg/kg of STZ was injected intraperitoneally for 5 consecutive days. SD rats were randomly divided into diabetic control and treatment groups. Treatment groups were administered with either 500 mg/kg of GRA (G500), 500 mg/kg of MF (M500), or 250 mg/kg of GRA mixed with same dose of MF (GM250) for 3 weeks. Blood glucose level and body weight were measured every 5th day. G500 and M500 both significantly reduced blood glucose levels as compared to the diabetic control group (diabetic control, 458.3$\pm$25.4 mg/dl; G500, 275.0$\pm$12.0; M500, 278.0$\pm$15.4; GM250, 324.0$\pm$18.4). While body weight in diabetic control group was decreased slightly after 3 weeks, treatment groups showed gradual increases of body weight during 3 week-period. Plasma insulin level was increased by treatment with GRA, but those levels in M500 and GM250 groups were similar to the diabetic control (normal control, 32.0$\pm$13.9 $\mu$IU/mι; diabetic control, 12.4$\pm$1.9; G500, 17.5$\pm$3.4; M500, 11.1$\pm$3.2; GM250, 10.5$\pm$t3.7). Urine glucose levels were also remarkably reduced in all treatment groups (normal control, 0.0$\pm$0.0 g/day; diabetic control, 11.4$\pm$2.5; G500, 4.9$\pm$0.2; M500, 5.7$\pm$1.6 ; GM250, 8.2$\pm$0.2). At the second and third week of the treatment, food and water intakes were determined. At the third week, food and water intakes were significantly decreased in all treatment groups. Taken together, we may conclude that GRA and MF alone may prevent or delay the development of hyperglycemia, however, synergistic hypoglycemic activity was not be seen in group treated with mixed formula of GRA and MF when compared to GRA or MF alone.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.105-110
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• 2017

This paper introduces a heave compensation system for offshore crane when it subjected to unexpected disturbances such as ocean waves, tidal currents or winds and their external force. The dynamic model consists of a crane which is considered to behave in the same manner as a rigid body, a hydraulic driven winch, an elastic rope and a payload. To keep the payload from moving upwards and downwards, PD(Proportional-Derivative) control was applied by using linearization. In order to achieve a better performance, the sliding mode control and the nonlinear generalized predictive control algorithm was applied according to the time-delay. As a result, the oscillating amplitude of the payload was reduced by the control algorithm. Considering the time-delay involved in the system to be one second, nonlinear generalized predictive controller with a robust controller was a suitable control algorithm for this heave compensation system because it made the position of te payload reach the desired position with the minimum error. This paper presented a control algorithm using the robust control and its simulation results.

• Journal of Power Electronics
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• v.19 no.3
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• pp.784-793
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• 2019

Two objectives can be pursued simultaneously with the ${\delta}$ control of a single-phase electric spring (ES). These objectives are the stabilization of the voltage across the critical load (CL) of a power system, and the achievement of a specific functionality similar to the pure compensation of reactive power or the correction of the power factor. However, existing control systems implementing the ${\delta}$ control do not cope with non-ideal operating conditions, such as line voltage distortions, and exhibit a somewhat sluggish regulation of the CL voltage. In an effort to improve both the steady-state and transient performances of an ES power system, this paper proposes implementing the ${\delta}$ control by means of a control system built up on the repetitive control and assisted by state feedback with pole assignment. This paper starts by analyzing the dynamics of an ES power system in terms of its poles and zeros. After that, a reduced second-order model of the dynamics is formulated to avoid a notch filter in the pole assignment. A repetitive control for an ES power system is then designed to meet the two above mentioned objectives. Experimental tests carried out on a laboratory setup demonstrate the effectiveness of the proposed control system in significantly improving the ES power system performance, while reaching the two objectives. In particular, the tests outline the large mitigation of harmonics in the CL voltage under line voltage distortions and its fast stabilization action.

• Korean Journal of Veterinary Service
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• v.30 no.1
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• pp.133-144
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• 2007

This study was conducted to determine the effective environmental control measures in preventing calf diarrheal disease in farms. It was found that the high numbers of calves in a cow house was directly related with the high incidence rate of diarrheal diseases. When the number of calves was increased in a cow house, it was difficult to reduce the diarrheal diseases of calves. It was revealed that the incidence rates of calf diarrheal disease were dramatically reduced when the delivery house which faced south. The periodical changes of bedding materials seemed beneficial good to control the possible resident infectious agents, including pathogenic viruses and bacteria. The control of the delivery time was important for reduction of calf diarrhea. It was revealed that September and October were the best time as the delivery period. In order to use old cow house as a delivery house, it should be sterilized by the disinfectant and the flame. When the diarrheal feces were removed as soon as possible, the transmission of diarrheal diseases among calves In the same house was reduced. When the diarrheal feces were not disposed, the incidence rate of diarrhea reached up to 50%. When the morbid calves were not quarantined, the incidence rate of diarrhea was 100%. In contrast, when the diseased calves were quarantined from other calves, the incidence rate of diarrhea was reduced, remarkably. The mean recovery time from the diarrhea of the treated calves in the southern cow house was much faster than that in the north cow house. The treatment of calves in a clean and well-ventilated cow house with dry bedding was more effective than that in a cold, wet, and dark house. It could be postulated that the most important environmental factor in the reduction of diarrheal diseases of calves is the blocking of the entry of the infectious agents. The complete sanitation and control of the delivery house in the using farm is more important than building a new cow house, for prevention of calf diarrheal diseases.

• Nuclear Engineering and Technology
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• v.32 no.4
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• pp.350-360
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• 2000

In Korea, the dose limits are reduced and are set at the ICRP-60 iimits. However, derived limits tabulated as MPC in air and water are still specified in Notice No.98-12. There are some discrepancies between the primary dose limits and MPCs in air and water. Therefore, in order to accept ICRP-60 recommendations fully, derived limits such as ALI, DAC, ECL for radiological protection against ionizing radiation based on ICRP-60 recommendations were calculated using modified methods of those of 10 CFR part 20, dose limits and committed effective dose coefficients of the Basic Safety Standards of the IAEA. The derived limits in this study were also compared with those prescribed in 10 CFR part 20 as well as MPCs of Notice No. 98-12 in order to analyze the impact of implementing derived limits on nuclear facilities. ECLs in air and water for the control of radioactive discharge into the environment in this study are shown to have lower values (i.e. more conservative), for most part, than those in Notice No. 98-12. Especially, for uranium elements, ECLs in water are approximately a magnitude in the order of two lower than those in Notice No.98-12.

• Steel and Composite Structures
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• v.37 no.1
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• pp.99-115
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• 2020

This article deals with the dynamic analysis in pad concrete foundation containing Silica nanoparticles (SiO₂) subject to seismic load. In order to control the foundation smartly, a piezoelectric layer covered the foundation. The weight of the building by a column on the foundation is assumed with an external force in the middle of the structure. The foundation is located in soil medium which is modeled by spring elements. The Mori-Tanaka law is utilized for calculating the equivalent mechanical characteristics of the concrete foundation. The Kevin-Voigt model is adopted to take into account the structural damping. The concrete structure is modeled by a thick plate and the governing equations are deduced using Hamilton's principle under the assumption of higher-order shear deformation theory (HSDT). The differential quadrature method (DQM) and the Newmark method are applied to obtain the seismic response. The effects of the applied voltage to the smart layer, agglomeration and volume percent of SiO₂ nanoparticles, damping of the structure, geometrical parameters and soil medium of the structure are assessed on the dynamic response. It has been demonstrated by the numerical results that by applying a negative voltage, the dynamic deflection is reduced significantly. Moreover, silica nanoparticles reduce the dynamic deflection of the concrete foundation.

• Journal of the Korean Institute of Gas
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• v.3 no.2 s.7
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• pp.62-69
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• 1999

This paper presents a design method of dynamic positioning control system(DPS) for floating Platform with rotatable and retractable thrusters using H$\infty$ servo control design method. The norm band of uncertainty is captured by multiplicative perturbation between nominal model and reduced order model. A controller robust to the uncertainty is designed applying H$\infty$ synthesis. The control law satisfying robust stability and nominal performance condition is determined through the mixed sensitivity approach. The control algorithm was evaluated on the basis of computer simulation for a proposed DPS design method and experiments was carried out with an image processing method for measurement of DPS position in a water tank The results of overall experiments show that proposed control method will be good to keep at a specified position. And they are compared with the experimental results by LQG synthesis and H$\infty$ optimal control design method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.5
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• pp.830-837
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• 2015

A study which is to develop the low-cost urban railway system for low-density line such as Gwang-ju subway Line 2 is in progress, and its TCS(Train Control System) is required as an economic system which is able to train operation suitable in low-density line. We have developed the signaling equipment which is configured with automatic block system between stations, and the control center's equipment in order to meet the requirements of TCS mentioned above. In this paper, we propose the control procedure of ATS to be required for train operation management in the low-density line such as Gwang-ju subway Line 2. The control procedure of ATS considered all features such as the requirements analysis for train operation management, the functions of train control system to be applied and the block type. Also, it considered the station(interlocking, passenger, turn-back) type, station control(stop, route, departure, turn-back departure, turn-back) type, and train operation management for exiting and entering depot. The ATS control procedure proposed in this paper has an advantage in the cost and efficiency through unification and optimization of its function. And in cost of operating and maintenance, the ATS system has a feature that can be significantly reduced.

• The Journal of Korean Medicine
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• v.27 no.4
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• pp.191-197
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• 2006

Objectives : The aim of this study was to evaluate the anti-depressant effect of Chilbokum on rats under the forced swimming test (FST) Methods : The rats were treated with the herbal extract, Chilbokum. In order to induce depression-like symptoms, the FST was conducted afterwards. The immobility time was measured during a 5-min experimental session. The alterations of the 5-HT level in the hypothalamus and hippocampus and the change of corticosterone level in the blood induced by FST were determined in the rats. Results : The results were as follows: 1. The immobility time during 5 min of FST in the drug administration group showed significant decreases compared with the control group (p<0.05). 2. The FST+Chilbokum group had significantly increased 5-HT levels of the hypothalamus and hippocampus, compared with the control group (p<0.05, respectively). 3. The FST+Chilbokum group had significantly decreased corticosterone levels, compared with the control group (p<0.05). Conclusions : These results demonstrate that the reduced immobility time by Chilbokum may be mediated by the increase in 5-HT level in the hypothalamus and hippocampus, suggesting that Chilbokum has a potential therapeutic efficacy for human depression.