• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.1
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• pp.27-38
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• 1992

The paper presents a digital speed control approach of induction motor systems by using a digital redesign method and adopting a well known 2nd order model as the system model equation. The basic concept using the modeling equation is induced from the control theory stand point such that we can describe usually the motor system connected by inverter, generator and load etc. just as a mechanical system to be controlled. The concept does not demand us the complicated vector-based modeling equation adopted in the traditional methods for the speed control of induction motor. The effectiveness of the servo control system composed by the above mentioned design concept is illustrated by the experimental results in the presence of step reference change and generator load variation. It is observed from the experimental results that the steady state error of the experimental set up becomes zero after some regulation time and the induction motor system is robust in spite of reference signal change and load variation of generator.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.7
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• pp.1096-1103
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• 2015

Electromagnetic levitation system(EMLS) is one of the well known nonlinear systems due to its high degree of nonlinearities. Moreover, when there are uncertain parameters in EMLS, it is not easy to have an accurate control of EMLS. In this paper, we first apply a standard input-output feedback linearzing controller to EMLS and investigate the possible control error caused by uncertain coil resistor. Then, as a remedy, we design and apply a robust controller using Lyapunov redesign technique to deal with this uncertain coil resistor in the system. The validity of our robust controller is verified via system analysis and experimental results.

• Journal of Korean Institute of Industrial Engineers
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• v.23 no.1
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• pp.77-94
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• 1997

Reengineering, also known as a business process redesign, involves a fundamental rethinking, and often a radical redesign, of an entire business process or a set of process to achieve dramatic improvements. The central paradox of reengineering is that its own advantages constitute the greatest threat to its success. For reengineering to be the right choice, the organization must have real capacities to embrace changes across the board. The key is to begin with, and to preserve, a vision of the new order, which drives this structured approach, and is in turn calibrated by that approach. However, in most cases of these calibrations, the empirical evidences on the effect of determinants in the reengineering are required. Seemingly, the research results in this area are scarcely verified. This article tried to search the effect of four dimensions of the reengineering toward the performance of reengineering. The results showed that the factors of the organization behavior and of the methodology/operation had more affected on the performance.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.645-649
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• 2005

In this study, redesign of a vaporizer sea-water pump has been carried out using computational fluid dynamics. The flow field of the specified pump model is simulated and analyzed. In the flow analysis full pump model has been used, and multi-block grids are employed to solve the governing equations. In order to improve pump efficiency, systematic redesign has been performed to remove the flow recirculation near the hub of the diffuser vanes. The modified model shows about 4 % improvement in pump efficiency compared to the given model.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.4-4
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• 2000

In this paper, the backstepping control method that is useful for cascade systems is applied to the slew maneuver of the spacecraft. The quaternion is used for representing the attitude of the spacecraft, because the reference trajectory of angular velocity has simple mathematical form. The conventional backstepping control has severa] problems such as slow convergence, trivial cancelling of nonlinear terms, and excessive control input. To overcome these problems, the modified backstepping control method which is redesign of Lyapunov function is proposed. To design a tracking function for angular velocity, it is necessary to estimate the process of maximum angular velocity, and therefore the estimation procedure using Bellman-Gronwall inequality is developed. To verify the effectiveness of the proposed control law, numerical simulation is performed and the results are compared with the exiting control scheme.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.4
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• pp.351-361
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• 2001

In this paper, a generalized framework called as robust internal-loop compensator(RIC) is presented, and by using this, a structural design method of sliding of sliding mode controller is proposed. First, a general sliding mode controller is derived and a stabilizing control input is designed based on Lyapunov redesign for the system in the presence of uncertainty and disturbance. And adopting the internal model following control, RIC is proposed. Next, using the structural characteristics of the proposed RIC, disturbance attenuation characteristics are analyzed and the performance of the closed-loop system is predicted. Through this analysis, it is shown that if the control gain of RIC is increased by N times, the magnitude of error is reduced to its 1/N. the proposed method is verified through experiments using a high-precision positioning system and the performance is evaluated.

• International Journal of Contents
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• v.15 no.4
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• pp.50-58
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• 2019

Baotu Spring Park, a must-visit place in Jinan, China, has been rated as the country's highest-level scenic spot by the Chinese government. However, social media that highly reflects public opinions tends to express a lower evaluation of Baotu Spring Park. Thus, this paper employs service design thinking methods to identify the problems of Baotu Spring Park and provide solutions from the perspective of visitors. Based on desk research, tourist behavior tracking, contextual interviews, and a customer journey map, it was found that the service gap of Baotu Spring Park lacks a unified and effective instruction system. Also, the activities, parking, and high-quality tourist souvenirs are deficient, and there is no online information delivery platform. Finally, five suggestions are made,-respectively:,- redesign the sign system, enhance the participation of tourists, redesign the tourist souvenirs and display space, offer parking areas and shuttle buses, as well as set up a dedicated application.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.954-957
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• 2002

The objective of design process modeling is a systematic support of rapid redesign process fur a modified input data. The design process modeling is realized by storing key parameters or geometric entities used in the intermediate design steps and reusing them for change of the designed parts or assemblies according to the modified input. In this paper, we adopted and implemented the design process modeling approach to our injection mold design system developed based on the Unigraphics system. It was proved that the productivity of mold redesign process is raised highly by introducing the design process modeling technique mold design system.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.6
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• pp.64-78
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• 1998

In this paper, on the basis of factory rationalization, the detection and evaluation system of weak assembly process was developed to analyze the processes for improvement of assembly productivity in the current assembly system. Using this detection and evaluation system of weak assembly process, the weak degrees of assembly process were quantitatively calculated. In this system, the improved design rules were constructed for assemblability and the redesign alternative was Presented for elimination of weak Process. After review of the redesign alternative, it was applied to the actual assembly system.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.442-451
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• 2015

Smartphone users are 15 billion in all round the world, and Korean smartphone users are estimated at 40million people to 83% of the Korean population. Selfie stick is most popular item among 20, 30's age users. And they use smartphones more than 90%. In survey they express inconvenience of using selfie stick. Inconveniences are as follows. * Heavy * Handle is inconvenient. * Mistiming during taking pictures * the range of shooting is not enough. In this paper the first improvement was that rod strength is slightly stronger. The second we divide a grip into 3 parts. If 3 parts are unfolded, these can use for tripod. We use deflection Interpretation for main Finite Elements Method program.