• Journal of Mechanical Science and Technology
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• v.17 no.3
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• pp.357-369
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• 2003

Electromagnetic valve (EMV) actuation system is a new technology for improving fuel efficiency and at the same time reducing omissions in internal combustion engines. It can provide more flexibility in valve event control compared with conventional variable valve actuation devices. The electromagnetic valve actuator must be designed by taking the operating conditions and engine geometry limits of the internal combustion engine into account. To help develop a simple design method, this paper presents a procedure for determine the basic design parameters and dimensions of the actuator from the relations of the valve dynamics, electromagnetic circuit and thermal loading condition based on the lumped method. To verify the accuracy of the lumped method analysis, experimental study is also carried out on a prototype actuator. It is found that there is a relatively good agreement between the experimental data and the results of the proposed design procedure. Through the whole speed range, the actuator maintains proper performances in valve timing and event control.

• ETRI Journal
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• v.39 no.1
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• pp.41-50
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• 2017

In connection-oriented data transport services, data loss can occur when a service experiences a problem in its end-to-end path. To resolve the problem promptly, the data transport systems providing the service must quickly modify their internal configurations, which are distributed among different locations within each system. The configurations are modified through a series of problem (event) handling procedures, which are carried out by multiple control processors in the system. This paper proposes a provisioning-to-signaling method for inter-control-processor messaging to improve the time efficiency of event processing. This method simplifies the sharing of the runtime event, and minimizes the time variability caused by the amount of event data, which results in a decrease in the latency time and an increase in the time determinacy when processing global events. The proposed method was tested for an event that required 4,000 internal path changes, and was found to lessen the latency time of global event processing by about 50% compared with the time required for general methods to do the same; in addition, it reduced the impact of the event data on the event processing time to about 30%.

• The Journal of Korean Medicine
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• v.19 no.2
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• pp.313-325
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• 1998

The effect of Holotrichia on natural killer cell activity in normal mouse were studied. 1. The oral administration of Holotrichia increased spleen weight about 21.1% and also cell numbers of spleen compared to control mice group. 2. The cytotoxicity of effector cell was most effectively induced in a ratio of 50 : 1(effector/target cell). 3. Cytotoxicity of effector cells was. increased about 24% as compared with control group in in vivo test. 4. On the other hand, the administration of Holotrichia original solution showed significant increase the cytotoxicity. The cytotoxicity was increased concentration dependently. 5. The cytotoxicity by $^{3}H-thymidine$ incorporation assay showed similar effect with LDH enzyme method. 6. In the purified NK cells, the cytotoxicity was increased about 31% as compared with control group in in vivo system and the ratio of cytotoxicity was generally more increased than that of partially purified NK cell. 7. In vitro experimet of the purified NK cells, the cytotoxicity was increased 11.8% as compared with control group and the ratio of cytotoxicity was also more increased than that of partially purified NK cell. These results suggest that Holotrichia is administrated to mice with malignant tumors, the increase of NK cell activity may occur and affect tumor cells.

• The Journal of Internal Korean Medicine
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• v.22 no.3
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• pp.367-377
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• 2001

Objectives: We aimed to identify. the effect of Jeongcheon-tang(定喘湯) and Cheongsangboha-tang(淸上補下湯) on the transcriptional activities of cytokine IL-4, IL-5, IL-6 and IL-10 involved in asthma model. Materials and Methods: RBL-2H3 cell lines were used. Cells were stimulated with calcium inophore($2{\mu}M$ : Sample group 1, $4{\mu}M$ : Sample group 2) for maximal gene expression. After 3rd treatment of samples and incubation(per 24hours), total cellular RNAs were collected using Trizol solution method. Then transcriptional activities of IL-4, IL-5, IL-6 and IL-10 were measured by RT-PCR with electrophoresis. Results: In IL-4 study, Jeongcheon-tang treated group showed 82.76%(Sample group 1) of transcriptional activities compared to the control group and Cheongsangboha-tang treated groups showed 85.77% (Sample group 1), 89.42% (Sample group 2) of transcriptional activities compared to the control groups. In IL-5 study, Jeongcheon-tang treated groups showed 88.24%(Sample group 1), 98.83%(Sample group 2) of transcriptional activities compared to the control groups and Cheongsangboha-tang treated group showed 73.66%(Sample group 2) of transcriptional activities compared to the control group. In IL-6 study, Jeongcheon-tang treated group showed 92.95%(Sample group 2) of transcriptional activities compared to the control group and Cheongsangboha-tang treated group showed n.40%(Sample group 2) of transcriptional activities compared to the control group. In IL-10 study, Jeongcheon-tang treated group showed 118.46% (Sample group 2) of transcriptional activities compared to the control group. Conclusions: This study shows that Jeongcheon-tang has the inhibitory effect on the transcription of IL-4, IL-5, IL-6 gene expression and the increasing effect on the transcription of IL-10 gene expression, and Cheongsangboha-tang has the inhibitory effect on the transcription of IL4, IL-5 and IL-6 gene expression in RBL-2H3 cell lines. Advanced studies are required to investigate the mechanisms of inhibition or increase by herbal medicine in asthma model.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.443-446
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• 2003

Conventional disturbance rejection methods have to derive the inverse model of a system. However, the inverse model of n nonholonomic system is not unique, because an inverse it changes depending on initial conditions and desired values. A kind of internal model control (IMC) using feedback error learning is discussed for the motion control of nonholonomic mobile robots in this paper, The present method is different from a conventional IMC whose control system consists of an inverse model, a direct model and a filter. The present disturbance rejection method need not use a direct model, where the remaining two elements are composed of the same inverse model based on neural networks.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.6
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• pp.313-320
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• 2015

In this paper, a method to obtain the probability distribution of room temperature and cooling load is presented, when the internal heat generation is applied to the system as a disturbance in the air conditioning system with slab cooling storage. The probability distribution of room temperature and the cooling load due to the disturbance were examined in one room of an office building. When considering only the electric power consumption as a probability component, it was found that the effect on room temperature and cooling load is small, because the probability component of the measured electric power consumption in the building is small. On the other hand, when considering the stochastic fluctuations of electric power consumption together with the heat generated by human bodies, the mean value of the cooling load was about 2,300 W and the ratio of the standard deviations was 19% (10 o'clock in second day). It was revealed that the stochastic effects of internal heat generation acting on the air conditioning system with slab cooling storage are not small.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.1
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• pp.59-67
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• 1997

This paper gives a controller design method by Linear Matrix Inequality(LMI) for internal combustion engine with Continuously Variable Transmission(CVT) which satisfies the given $H_\infty$ control performance and robust stability in the presence of physical parameter perturbations. To the end, the validity and applicability of this approach are illustrated by simulation in the all engine operating regions.

• Korean Journal of Remote Sensing
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• v.14 no.2
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• pp.129-136
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• 1998

This paper deals with a problem encountered in the course of constructing digital elevation model from a contour map. Deficiencies of widely used linear interpolation method is described, and an interpolation method for internal points of a single closed contour is proposed. Control points not on a plane are searched and interpolated. The method is applied to an artificial contour lines and real contour lines. The result shows natural and accurate reconstruction.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.339-346
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• 2017

This paper proposes a sensorless control method to improve the performance of an internal permanent magnet synchronous motor (IPMSM) control by using a full-order flux observer in a wide speed range. The conventional sensorless control method uses a constant gain for high performance at low-speed region. However, this method has drawbacks such as an increased angle error and current ripple in the high-speed region due to the fixed gain value. In order to overcome this problem, the gain of the full-order flux observer is changed by considering the angle error in the whole speed range. The proposed method minimizes the angle error for each region of the speed range by applying a relevant gain value, which improves the current ripple reduction and motor noise cancellation. The validity of proposed sensorless control method is verified by a simulation and an experiment.

• Journal of Korean Academy of Nursing Administration
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• v.13 no.2
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• pp.242-253
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• 2007

Purpose: The aim of this study is to examine the effectiveness of an computer-tailored intervention program to promote breast-feeding. Method: A quasi-experimental design was used assigning forty pregnant women to the experimental group (computer-tailored intervention condition) and the control group (no-intervention control condition). Thirty-three participants completed pretest and posttest questionnaires and 19 participants assigned to intervention condition received personal feedback tailored by computer program. Result: Participants in the experimental group showed higher mean score of 'perception of the importance of breast-feeding'. Significant differences in internal health locus of control was found between the participants in the experimental group and the control group. Participants in the experimental group exceeded controls on intention of breast-feeding. Participants in the control group more often felt that the length of program contents they received was somehow longer. Conclusions: The use of a computer-tailored intervention improved the perception of the importance of breast-feeding and the internal health locus of control. The intention of breast-feeding was increased through the personal feedback tailored by computer even though participants felt that the length of program contents of tailored feedback was not longer.