• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.2
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• pp.74-80
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• 2003

In this paper, a robust two-degree-of-freedom(TDF) the speed control system using $H_{\infty}$ optimization method and real genetic algorithm is proposed for the robust stability and the robust performance in dc servo motor system. This control system composed of feedback and feedforward controller. The feedback(FB) controller with $H_{\infty}$ optimization method is designed for real genetic algorithm that is model matching problem using mixed sensitivity function. The feedforward(FF) controller with $H_{\infty}$optimization method is minimized the error between transfer function of the optimal model and the overall transfer function. The proposed robust two-degree-of-freedom speed control system is simulated to the dc servo motor. By the simulation, feedback controller can obtain the robust stability property and feedforward controller can obtain the robust performance property under modelling error. The performance of the dc servo motor is analyzed by the experiment setting. The validity of the proposed method is verified through being compared with pid(proportional integrated differential)control system design method for the dc servo motor.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.6
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• pp.789-796
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• 2016

In the Core Technology R&D of the defence area, the development of the related core element technology could be the foundation to develop advanced weapon system in the future. But it might make various problems if you can not accurately define the TRL of the element technology. In other words, if the technology is not sufficiently mature and then the project starts, it might require an increase in the development period and additional cost. Finally the system will be in an incomplete state and result in user dissatisfaction and the project failure. Therefore it is a very important task to properly assess the TRL for a successful project. In this study, We propose the method for risk management of core technology R&D project of the defence area using the QFD process with degree of difficulty and technology readiness level. It is also presented the process to determine the risk level using TRL and Degree of difficulty. Finally We apply this method to UGV system for verifying the result of this study.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.706-713
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• 2014

An enhanced 360-degree integral-floating three-dimensional display system using a hexagonal lens array and a hidden point removal operator is proposed. Only the visible points of the chosen three-dimensional point cloud model are detected by the hidden point removal operator for each rotating step of the anamorphic optics system, and elemental image arrays are generated for the detected visible points from the corresponding viewpoint. Each elemental image of the elemental image array is generated by a hexagonal grid, due to being captured through a hexagonal lens array. The hidden point removal operator eliminates the overlap problem of points in front and behind, and the hexagonal lens array captures the elemental image arrays with more accurate approximation, so in the end the quality of the displayed image is improved. In an experiment, an anamorphic-optics-system-based 360-degree integral-floating display with improved image quality is demonstrated.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.346-349
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• 2015

Generally, in order to verify the degree of tire wear or abnormal wear, a driver or an auto mechanic checks the degree of tire wear and the existence of tire abnormality, directly with the naked eye or by way of using a gauge equipment. In case of such verification, individual subjective judgments may be involved or a driver may suffer heavy burdens to expend the time and cost for using the wheel alignment equipment. Therefore, this thesis will use a number of laser sensors to check the existence of abnormal wear and the degree of wear on each tire and develop a system checking the sides of tires to receive the tire information, so that subjective judgments may be overcome and objective and accurate judgments may be rendered.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.5
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• pp.580-585
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• 2012

In this paper, the cycle performance analysis for condensation and evaporation capacity, total work and efficiency of ocean thermal energy conversion power system using R744 ($CO_2$) is presented to offer the basic design data for the operating parameters of this system. The operating parameters considered in this study include superheating and subcooling degree, evaporation and condensation temperature, pump and turbine efficiency. The main results were summarized as follows : The evaporation capacity of R744 increases with superheating and subcooling degree, but decreases with the increasing condensation temperature. The total work increases with superheating and subcooling degree of R744, but decreases with the increasing evaporating temperature. And, the efficiency increases with subcooling and superheating degree, but decreases with the increasing condensation temperature. Therefore, superheating and subcooling degree, evaporation and condensation temperature and pump and turbine efficiency of R744 OTEC power system have an effect on the evaporation and condensation capacity, total work and efficiency of this system. With a thorough grasp of these effect, it is necessary to design the OTEC power cycle using R744.

• Korean Management Science Review
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• v.20 no.1
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• pp.25-36
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• 2003

Now that many organizations have invested a tremendous amount of money and efforts to operate Web sites on the Internet, there is a strong demand to understand the effectiveness of such investments. In other words, one of most frequent and important questions about their Web sites is "Will the current Web site management policy be effective enough to have more visitors come to our Web site\ulcorner" In this paper, a system which predicts the degree of user interest in the future to Web sites is constructed. The degree of user interest to a Web site is defined to be the visit counts for the Web site in the system. With higher the visit counts, the related site is considered to be more interesting. However, the figures of the visit counts themselves cannot explain properly the degree of user Interest in the future to the related Web sites (i.e. the effectiveness of the related Web sites). Therefore, the system also uses mechanisms which use the concept of the Moving Averages, which have been used frequently in the stock exchanges. In this paper. two prediction mechanisms are proposed and compared. The first mechanism uses the Golden Cross/the Dead Cross of the Moving Averages, while the second mechanism uses the changes of upward/downward direction of the Moving Averages. Experimental results show that the two prediction mechanisms proposed in this paper predict the degree of user interest in the future to the related Web sites very well in most cases. However, the first one is considered to be better than the second one In the sense that the second one is too much sensitive to the changes of visit counts.it counts.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.73-86
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• 1999

This study was performed to find out factors affecting degree of satisfaction with workers' working environment. The study subjects were 165 workers who were working at painting process of twelve furniture manufacturing factories in Incheon area. We used self-administered questionnaire containing general characteristics, working conditions, the degree of satisfaction with working environment, and the degree of satisfaction with working condition. In addition, we measured the exposure levels of occupational hazardous agents. The results were as follows; 1. Correlations between the degree of satisfaction with workers' working environment and the measured of occupational hazardous agents did not affect the degree of satisfaction with workers' working environment. 2. Factors affecting the degree of satisfaction with workers' working environment were not the exposure levels of occupational hazardous agents, but the degree of satisfaction with working condition, size of industry, health status, and types of ventilation system. As the degree of satisfaction with working condition was increased, the degree of satisfaction with working environment was increased. Also, for the workers who had good health status, the degree of satisfaction with work environment was appeared to be high. To increase the degree of satisfaction, with workers' working environment, firstly, effective work management and production control are required. Also, the worker's effort to negotiate continuously with top manager on improving working conditions is required. Secondly, developing heath promotion program to be appropriate for the characteristics of worksite is required. Moreover, leading worker's participation in health promotion program is very important to increase the degree of satisfaction with workers' working environment.

• Journal of Engineering Education Research
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• v.13 no.5
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• pp.61-65
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• 2010

As an activity of one working group for the Good Practice program at Kumamoto University, we proposed a questionnaire survey on the degree in which students understand the uppermost points of importance in their classes in addition to the usual type of class questionnaire. Each class lists three uppermost points of importance which are essential for understanding the class content. The degree of understanding is classified into four levels: full, most, insufficient, and not at all understandings. Through the analysis of questionnaire replies, the degree of understanding for bachelor students in the Department of Engineering was discovered to be meaningfully affected by the degree of difficulty, the effectiveness of audiovisual aids, self-study time, and class attendance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.5
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• pp.745-749
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• 2017

Climate change and energy security are major factors for future national energy policy. To resolve these issues, many countries are focusing on creating new growth industries and energy services such as smartgrid, renewable energy, microgrid, energy management system, and peer to peer energy trading. The financial and economic evaluation of new energy services basically requires energy savings estimation technologies. This paper presents the baseline load estimation method, which is used to calculate energy savings resulted from participating in the new energy program, using moving average model with heating degree days (HDD) and cooling degree days (CDD) adjustment. To demonstrate the improvement of baseline load estimation accuracy, the proposed method is tested. The results of case studies are presented to show the effectiveness of the proposed baseline load estimation method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.6
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• pp.927-934
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• 2017

This paper is concerned with applicability of two-degree-of-freedom controllers to the recently suggested i-PID controllers, in which unknown parts of the plant are taken into account without any modeling procedure. First, i-PID controller with two-degree-of-freedom is applied to a specific model, called Anisochronic model, to confirm the usefulness of this method. Second, using the original examples of i-PID controllers, it is confirmed that performance/robustness of system are to be improved due to two-degree-of-freedom, especially when the input changes suddenly. It is seen that as the desired robustness increases the optimal value of two-degree-of-freedom parameter ${\alpha}_A$ would be negative. It is checked and verified that if this value was limited to 1 or less as is generally known, performance would be degraded.