• Journal of Drive and Control
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• v.16 no.1
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• pp.29-35
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• 2019

The control performance of hydraulic systems is basically influenced by the performance of electrohydraulic servo valve incorporated in a hydraulic control system. In this study, a control design was proposed to improve the control performance of a servo valve with a non-contact eddy current type position sensor. A mathematical model for the valve was obtained through an experimental identification process. A PI-D control together with a feedforward (FF) control was applied to the valve. To further improve the dynamic response of the servo valve, an input shaping filter (ISF) was incorporated into the valve control system. Finally, the effectiveness of the proposed control system was verified experimentally.

• The Journal of Korean Academic Society of Nursing Education
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• v.23 no.2
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• pp.135-145
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• 2017

Purpose: The purpose of this study was to develop a program outcomes assessment system based on Course Embedded Assessment for nursing education. Methods: This study was conducted in accordance with the procedures of the developmental research method. Results: The major results are as follows. 1) The program outcomes were measured according to the Analytic Hierarchy Process. 2) The Course Embedded Assessment matrix was made according to program outcomes' weight, the curriculum-organizing principle, and achievement levels. 3) The Course Embedded Assessment rubric was developed in logical process, and consisted of a performance criterion, and rating scale. The content validity index of the Course Embedded Assessment rubric was 0.85. 4) An evaluation guideline and 12 documents were developed to facilitate the performance of the assessment system. 5) The average content validity index of the Course Embedded Assessment-based program outcomes assessment system was as high as 0.89. Conclusion: A Course Embedded Assessment-based program outcomes assessment system is more suitable for accreditation of nursing education than previous studies. Because this system evaluates the process of achievement as well as program outcomes, the results can also serve as immediate feedback to improve the educational process. Above all, this system facilitates that students check their achievements and strive to acquire core competencies in nursing.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.2
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• pp.132-139
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• 2009

Yield is a very important measure that can expresses simply for productivity and performance of company. So, yield is used widely in many industries nowadays. With the development of the information technology and online based real-time process monitoring technology, many industries operate the production lines that are developed into automation system. In these production lines, the product structures are very complexity and variety. So, there are many multi-variate processes that need to be monitored with many quality characteristics and associated process variables at the same time. These situations have made it possible to obtain super-large manufacturing process data sets. However, there are many difficulties with finding the cause of process variation or useful information in the high capacity database. In order to solve this problem, neural networks technique is a favorite technique that predicts the yield of process for process control. This paper uses a neural networks technique for improvement and maintenance of yield in manufacturing process. The purpose of this paper is to model the prediction of a sub process that has much effect to improve yields in total manufacturing process and the prediction of adjustment values of this sub process. These informations feedback into the process and the process is adjusted. Also, we show that the proposed model is useful to the manufacturing process through the case study.

• Journal of the Korean Society for information Management
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• v.32 no.1
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• pp.7-22
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• 2015

This paper describes a Web search optimization study that investigates both static and dynamic tuning methods for optimizing system performance. We extended the conventional fusion approach by introducing the "dynamic tuning" process with which to optimize the fusion formula that combines the contributions of diverse sources of evidence on the Web. By engaging in iterative dynamic tuning process, where we successively fine-tuned the fusion parameters based on the cognitive analysis of immediate system feedback, we were able to significantly increase the retrieval performance. Our results show that exploiting the richness of Web search environment by combining multiple sources of evidence is an effective strategy.

• Information Systems Review
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• v.16 no.1
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• pp.1-15
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• 2014

Despite the sizable growth of the group buying market, consumer complaints have recently raised skepticism about the future of these sites. Thus, building a trustworthy transaction environment has become a critical issue. In exploring a trust-building mechanism, we pay particular attention to the role of merchandisers who specialize in finding products or services and marketing them to potential buyers on group buying sites. The purpose of this study is to examine whether providing merchandiser feedback comments and performance profiles on group buying sites leads consumers to evaluate the community of merchandisers more favorably and makes them more likely to purchase products or services. Research hypotheses were tested with data obtained from 124 subjects who participated in a laboratory experiment. The results empirically demonstrate that merchandiser feedback comments and performance profiles enhance buyers' trust in the community of merchandisers participating in a group buying site. This enhanced trust, in turn, increased buyers' intention to purchase products or services through the group buying site.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.237-242
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• 1993

In the cluster tool, it is necessary to precisely control the vacuum pressure for the wafer transportation between transport module and cassette or process with the range of 10 $^{-4}$ to 5*10 $^{-5}$ torr. So we have designed the pressure control system for the transport module of the cluster tool and have evaluated its performance. Digital PID is utilized with the weighted sum of both three previous errors and one current error. The feedback signal is put into the nitrgen mass flow controller using the transport module controller. This pressure control system can prevent the transport module from the particle generation and backstreaming of hazardous process gases of the process chamber.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.11
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• pp.963-969
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• 2005

An advanced method of Relaxed Static Stability (RSS) is utilized for improving the aerodynamic performance of modem version supersonic jet fighter aircraft. The flight control system utilizes RSS criteria in both longitudinal and lateral-directional axes to achieve performance enhancements and improve stability. The T-50 advanced trainer employs the RSS concept in order to improve the aerodynamic performance and the flight control law in order to guarantee aircraft stability, The T-50 longitudinal control laws employ the dynamic inversion and proportional-plus-integral control method. This paper details the design process of developing longitudinal control laws for the RSS aircraft, utilizing the requirement of MIL-F-8785C. In addition, This paper addresses the analysis of aircraft characteristics such as damping, natural frequency, gain and phase margin about state variables for longitudinal inner loop feedback design.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.10
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• pp.1772-1777
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• 2003

This paper presents the design, fabrication, and calibration of a piezoelectric polymer-based sensorized microgripper. Electro discharge machining technology is employed to fabricate super-elastic alloy based micro gripper. It is tested to present improvement of mechanical performance. For integration of force sensor on the micro gripper, the sensor design based on the piezoelectric polymer PVDF film and fabrication process are presented. The calibration and performance test of force sensor integrated micro gripper are experimentally carried out. The force sensor integrated micro gripper is applied to perform fme alignment tasks of micro opto-electrical components. It successfully supplies force feedback to the operator through the haptic device and plays a main role in preventing damage of assembly parts by adjusting the teaching command.

• Korean Management Science Review
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• v.26 no.3
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• pp.37-54
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• 2009

E-learning is a networked phenomenon allowing for instant revisions and distribution, and goes beyond training and instruction to the delivery of information and tools to improve performance. The proponents of e-learning emphasizes that students learn more effectively when they interact and are involved with other students participating in similar endeavors. The paper outlines the process of development and design of e-learning based Management Sciences course, with the aim of ensuring widespread use, in undergraduate business program. Experiences in introducing students to e-learning course are reported. Feedback from students has been very positive but also indicates the need for ongoing support and direction. In addition, a survey was used to identify the determinants of students' academic performance of Management Science, and PLS based model is developed to analyze the results. Statistical results concerning the hypothesized model are provided.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1997.11a
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• pp.181-186
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• 1997

Transcoding is the key technique to further reduce the bit-rate of a previously compressed video. The performance of the transcoding is evaluated by the two factors, the accuracy on the target bit-rate and the complexity of the implementation. In this paper, were propose a new rate control algorithm which has very accurate bit-rate control performance and much smaller computational complexity. For the accuracy problem, we empirically observe the relationship between the quantization step size and generated bits in requantization process and then find that the relationship can be characterized as the new piece-wise linear model. For the complexity problem, we reduce the role of feedback rate control. The simulation results show that the proposed method gives the better performance in the accuracy with the same picture quality than conventional rat control algorithm.