• International Journal of Automotive Technology
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• v.7 no.7
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• pp.821-826
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• 2006

This paper describes a rollover index (RI)-based rollover mitigation control (RMC) system. A rollover index which indicates an impending rollover has been developed by a roll dynamics phase plane analysis. The rollover index is calculated using the roll angle, the roll rate, the lateral acceleration and time to wheel lift (TTWL). A differential braking control law based on a 2-D bicycle model has been designed using the direct yaw control (DYC) method. An RMC threshold has been determined from the rollover index. The performance of the RMC scheme and the effectiveness of the proposed rollover index are illustrated using a vehicle simulator.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5B
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• pp.415-429
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• 2011

Quantitative evaluation indexes for flood control effect of a multi-purpose reservoir used widely in Korea are the discharge control rate, reservoir release rate, reservoir storage rate, and flood control storage utilization rate. Because these indexes usually use and compare inflow, release, and storage data directly, the uncertainties included in these data are not considered in evaluation process, and the downstream flood control effects are not assessed properly. Also, since the acceptable partial failure in a design of water resources system is not considered, the development of a new flood control effect evaluation index is required. Fuzzy set theory is therefore applied to the development of the index in order to consider the data uncertainty, the downstream flood control effect, and the acceptable partial failure. In this study, the flood control effect of a multi-purpose reservoir is evaluated using the flood control effect index developed by applying fuzzy set theory. The Chungju reservoir basin was selected as a study basin and the storm events of July, 2006 are used to study the applicability of the developed index. The related factors for flood control effect are fuzzified, the acceptable failure region is divided from the system state to evaluate the flood control effect using developed flood control effect index. The flood control effect index were calculated by applying to the study basin and storm events. The results show that the developed index can represent the flood control effect of a reservoir more realistically and objectively than the existing index.

• International Journal of Control, Automation, and Systems
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• v.3 no.1
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• pp.100-108
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• 2005

This work presents a novel control index to regulate the pump speed of an axial flow blood pump for the left ventricular assist device (LVAD). The control index is based on the characterization of pump operating conditions such as normal or suction status. The pump operating characteristics reveal that a certain pulsatility relationship between the pump pressure difference and the pump flow is a unique index to identify the pump operating status under the diverse pump operating environments.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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• pp.1996-2005
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• 2010

This paper proposes a new method for constant control of the output AC voltage of a voltage-fed three phase Z-source inverter (ZSI), in case of Z-network DC voltage variation or heavy change of load. The modulation index for the reference output AC voltage of ZSI can be calculated by the basic definition of ZSI, the input DC voltage and capacitor voltage of Z-network. And, the output AC voltage of ZSI is controlled by the modified space vector modulation (SVM) with the calculated modulation index. By the proposed method, the modulation index of output AC voltage is closely following in the reference modulation index. The validity of the proposed method is verified using PSIM simulation. In case which the input DC voltage of ZSI is heavily changed from 100[V] to 70[V] (or to 150[V]) and in case which load is changed from $30[\Omega]$ to $10[\Omega]$, we confirmed that the output AC voltage of ZSI is constantly controlled by the proposed method because the modulation index of ZSI is also simultaneously changed. Finally, FFT and %THD of the output voltage and current of ZSI by the proposed method are analyzed.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.13 no.1
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• pp.19-30
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• 2013

Recently, the constrained index tracking problem, in which the task of trading a set of stocks is performed so as to closely follow an index value under some constraints, has often been considered as an important application domain for control theory. Because this problem can be conveniently viewed and formulated as an optimal decision-making problem in a highly uncertain and stochastic environment, approaches based on stochastic optimal control methods are particularly pertinent. Since stochastic optimal control problems cannot be solved exactly except in very simple cases, approximations are required in most practical problems to obtain good suboptimal policies. In this paper, we present a procedure for finding a suboptimal solution to the constrained index tracking problem based on approximate dynamic programming. Illustrative simulation results show that this procedure works well when applied to a set of real financial market data.

• Journal of the Korean Society of School Health
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• v.12 no.1
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• pp.27-44
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• 1999

Obesity in children is a major concern of public health. This study was performed to illuminate its effect on weight control program and the associated factors of obesity-related habits and obesity index in primary school obese children. Weight control program consisted of behavioral modification, nutrition education and exercise during 17 weeks. The sample consisted of treatment group(n=42) and control group(n=41). There was no statistical difference between the two groups in obesity index, socioeconomic status and grade. To assess the effects of weight control program, the subjects were given pre-test and post-test such as the measurement of anthropometric values and self-reporting questionnaire. This result of this study were as follows; 1. After weight control program was applied, there was a significant decrease in obesity index among the treatment group. Obesity-related habits score of the treatment group increased significantly, While there was not much difference between the pre-test and the post-test among the control group. But exercise habit didn't increase significantly in the both groups. 2. Correlation between obesity-related habits and obesity index were not evident. 3. After application of weight control program, the factors associated with change of eating habit were children's past experience of weight control, motivational change toward weight control program and friends' support for treatment group. The factors associated with change of exercise habit were post-test motivation score and friends' support. Motivational change toward weight control and pre-test self-efficacy of exercise behavior were counter-related to exercise habit. For change of other obesity-related habits, initial obesity index, motivational change, post-test self-efficacy score of exercise behavior and paternal educational status were closely associated. But post-test self-efficacy score of eating behavior was unrelated. 4. Only the factor of experience of weight control was associated with change of obesity index. 5. For the both groups, the factors associated with change of eating habits were post-test self-efficacy of eating behavior and family's support. The factors associated with change of exercise behavior were self-efficacy changes of exercise behavior and friends' support. The factors associated with change of other obesity-related habits were self-efficacy change of eating behavior. Initial obesity index was associated with change of obesity index. 6. The rate of dropouts from weight control program was 28.6% (12/42) in treatment group. Initial obesity index, other obesity-related habits except eating exercise habits, friend's support were associated with dropout. In conclusion, these results indicated that weight control program in primary school settings was effective. Direct exercise regimen and practice was demanded. In addition to the program itself, much of the success is dependent on the degree of motivation of the children involved and support provided by their parents and friends. Further study need to be performed under the condition that the weight control progrom is applied for a longer period.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1515-1522
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• 2011

This paper proposes the algorithm for the output AC voltage control of Z-source inverter by the detection of the input DC voltage and Z-network capacitor voltage. The actual modulation index of the proposed method is detected by the capacitor voltage in Z-network and input DC voltage of three-phase Z-source inverter. Control modulation index for the output voltage control is calculated by the detected actual modulation index and reference modulation index. And, calculated control modulation index is applied to the modified space vector modulation (SVM) for control the output voltage of Z-source inverter. To verify the validity of the proposed method, PSIM simulation was achieved and a DSP controlled 1[kW] three-phase Z-source inverter was producted. The simulation and experiment were performed under the condition that the load was changed in case of the constant input DC voltage and the input DC voltage was changed in case of the load was constant. As a result, we could know that the output phase voltage of Z-source inverter followed to the reference voltage 70[VRMS] despite the load or the input DC voltage were suddenly changed.

• Journal of radiological science and technology
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• v.43 no.2
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• pp.115-121
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• 2020

In a digital radiation system using a Flat Panel Detector, we attempted to the quality control of digital radiography system using the Exposure Index and Deviation Index. Calibration was performed with the radiation quality suggested by the International Electrotechnical Commission, and through an experiment using a phantom, appropriate inspection radiation conditions applicable to medical institutions were selected. The study was conducted using the selected radiation conditions. Through those chest posterior anterior image, information such as examination conditions and exposure index was obtained. The deviation index was derived by analyzing the exposure index based on the target exposure index calculated by the phantom study. As for the analyzed exposure index, 97.1% was distributed within the range of ± 2.0 based on the deviation index. Quality control of medical images should be performed through management of inspection conditions through exposure index and deviation index and management of medical images.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.4
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• pp.237-243
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• 2012

This paper proposes quantitative investment strategies for KOSPI200 index futures using VKOSPI and control chart. Stochastic control chart is employed to decide when to take a position as well as what position out of long and short should be taken by monitoring whether VKOSPI or difference of VKOSPI touches the control limit lines. The strategies include 4 approaches, which are traditional control chart and 2-Area control chart coupled with VKOSPI and its difference, respectively. Computational experiments using real KOSPI200 futures index for recent 3 years are conducted to show the excellence of the proposed investment strategies under control chart framework.

• Journal of Acupuncture Research
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• v.30 no.3
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• pp.27-38
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• 2013

Objectives : This study was designed to evaluate patient satisfaction of Korean medicine therapy using treatment tool by psychological type. Methods : 48 subjects were participated in this study. Before a treatment, we analyzed a patient's phychological type first by using a questionnaire. And then we divided 3 groups which were called a rational sympathy module group, emotional sympathy module group, control group. Manner of medical consultation according to patient's phychological type was carried out in all groups. After all treatment, we conducted a survey about medical service perception index, patient happiness index, medical satisfaction index. To evaluate a satisfaction degree, we analyzed results of survey statistically. Results : The results of the analysis, both rational sympathy module group and emotional sympathy module group got a higher score than control group statistical significantly on medical service perception index. Emotional sympathy module group got a higher score than control group statistical significantly on patient happiness index and medical satisfaction index. But rational sympathy module group only had a higher tendency than control group on patient happiness index and medical satisfaction index. Emotional sympathy module group got a higher score than rational sympathy module group on medical service perception index, patient happiness index and medical satisfaction index. Conclusions : Korean medicine therapy using treatment tool by psychological type consisted of patient's phychological type questionnaire and manner of medical consultation could improve a patient's satisfaction. It was more effective in emotional sympathy module group than rational sympathy module group.