• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.1
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• pp.9-16
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• 2016

A position control system composed of the PMLSM(Permanent Magnet Linear Synchronous Motor), unlike conventional linear permanent magnet synchronous motor is fixed to the permanent magnet moving coil rails (permanent magnet = stator, coil = mover), the coil is fixed, moving the permanent magnet, we propose a position control system (permanent magnet = mover, coil = stator) structure. Position is measured not using conventional encoder or resolver but by adopting vector control method using 2 hall sensors generating rectangular signal. This method estimate the velocity and position of mover by using the quadruple of two hall sensor signal instead of encoder signal. Vector control of PMLSM using 2 hall sensor generating rectangular wave is proved to control the system stable and efficiently through simulation. Also hardware experiment reveals that the position control performance is measured within the range of $30{\sim}50{\mu}m$ in the accuracy of $10{\sim}20{\mu}m$, which is improved twice to the conventional method. The proposed method exhibits its economical efficiency and practical usefulness. The vector control technique using two hall sensors can be installed in narrow place, accordingly it can be implemented on the system where the conventional encoder or resolver cannot operate.

• Journal of Korea Game Society
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• v.9 no.3
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• pp.107-119
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• 2009

Online games belong to a technology-oriented service industry that has emerged from the assimilation of game contents and communication networks in the respective realms of culture technology (CT) and information technology (IT). This study examines the individual acceptance of online games as entertainment-oriented technology based on the belief-attitude-intention paradigm and the underlying hedonic and utilitarian motivations. To measure the latent variables influencing the acceptance process, a structured questionnaire was developed based on the existing Technology Acceptance Model. Research model analysis and hypothesis testing were carried out using a structural equation model. Results indicated that latent variables reflecting hedonic and utilitarian characteristics had a significant influence on user behavior in the acceptance of online games. By uncovering the core factors in! fluencing the acceptance of online games and thereby theoretically verifying the latent variables influencing the acceptance of entertainment-oriented technology, this study provides strategic implications for business models by game companies aimed at attracting a large user base and dominating the market.

• Journal of Digital Convergence
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• v.13 no.4
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• pp.191-203
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• 2015

In foreign language, vocabulary is the most essential and fundamental elements. Traditional language learning methods that are to understand and to memorize the English contents can only be obvious limitations. In this paper, we proposed the speaking-centered learning methods based on cognitive strategies and speech recognition considering the learner characteristics. We have designed and implemented the cognitive strategy-based speaking training system for acquisition elementary English vocabulary. We were divided into control group and the experimental group and applied to the system to analyze the learning effect. The result of Analysis, the proposed system is increased motivation and achievement of learners. In addition, the proposed system is improved an academic learning participation, Project accomplish, self-interesting and leadership skills. Through this study, we expect that students improve the ability of practical skills in speaking English.

• Industry Promotion Research
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• v.5 no.1
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• pp.53-62
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• 2020

This study reviewed the structural and operational systems of two professional learning communities in Korean society and analyzed their strengths and weaknesses: the Association of Korean History Teachers and the Communities of Elementary School Classroom Management. In order to analyze these cases, Robey's organizational change model was used as a theoretical frame. Two research methods were mainly employed for this study: literature review and on-site interviews. The analysis found several strengths (easy accessibility, led by teachers' initiative and autonomous will, abundant and practical teaching solutions) and weaknesses (financial burden, lack of theoretical background, sporadic participants). In conclusion, this study suggests three strategies for an educational leader who has an important role in developing a teacher's professionalism: 1) Make an institutional effort to stimulate teachers' motivation to learn, 2) Create a strong network of university professors and other experts for career advice, 3) Build a synthesized and consolidated system.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.12
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• pp.36-45
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• 1998

In this paper, a method of on-line PI gain-tuninng is proposed for the speed control of brushless D.C. motor by investigating the pattern of input and output without estimating parameter. Proportional gain is tuned in the process to obtain a fast speed response by supplying the maximum constant input. And integral gain is appropriately tuned in the process of proportional control so that the response may be stably converged and the overshoot may be prevented. Therefore because both control and gain-tuning are executed concurrently, additional works that estimate parameters and so on aren't required in the proposed method. In the proposed method, both fast-response and overshoot problem are well solved, and it is more useful and convenient than existing auto-tuning methods in the speed control of D.C. motor. It is illustrated by simulations and experimental results that the proposed method is useful and stable.

• The Journal of the Korea Contents Association
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• v.16 no.3
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• pp.305-318
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• 2016

Perceptions of organizational politics(POPs) have stress-based effect as job demand and lead to employee's negative attitudes and behaviors. According to job demand resource model, burnout develops when high job demand deplete employee's resources, which lead employees to low levels of motivation and high levels of cynicism and frustration. Currently, in studying the relationship between POPs and burnout there is a lack of researches on certain settings and conditions. The present study examined a model in which relationship between POPs and burnout was mediated by psychological need satisfaction. And also, this study tested moderating role of psychological capital between POPs and need satisfaction. A total of 220 employees in telco and electronic manufacturing company in South Korea participated in this study. The result of this study showed that need satisfaction works as mediating variable between POPs and burnout and psychological capital had moderating effect between POPs and need satisfaction. This study proposes a new framework of POPs by examining linking mechanism of need satisfaction and psychological capital. The results of this study provide practical insight to HR practitioners and business leaders.

• Journal of Internet Computing and Services
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• v.17 no.3
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• pp.45-54
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• 2016

Medical images are an effective means to identity medical abnormalities.. Patients typically have medical images taken at different clinics during lifetime, and they often wish to have second interpretation on medical images showing substantial diseases. At present, since personal medical images are distributed to multiple clinics, there is a bit discomfort that patients directly bring their images by hands to get the second interpretation from another physician. With these two motivations, we design a cloud service for archiving medical images and interpreting medical images by physicians. We present the design and implementation of the service, and show its practical value as low-cost personal healthcare service. By using the service, patients can retrieve and review their medical images anytime and have a convenience of acquiring second opinions on their medical images at low-cost without visiting a clinic.

• Journal of Internet Computing and Services
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• v.7 no.6
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• pp.157-174
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• 2006

Ajax interaction model changes the posture of web application to become a stateful over HTTP. Ajax applications are long-lived inthe browser. XMLHTTPRequest (XHR) is used to facilitate the data exchange. Using HTTPS over this interaction is not viable because of the frequency of data exchange. Moreover, switching of protocols form HTTP to HTTPS for sensitive information is prohibited because of server-of-origin policy. The longevity, constraint, and asynchronous features of Ajax application need to hove a different authentication and session fondling mechanism that invoke re-authentication. This paper presents an authentication and session management scheme using Ajax. The scheme is design lo invoke periodic and event based re-authentication in the background using digest authentication with auto-generated password similar to OTP (One Time Password). The authentication and session management are wrapped into a framework called AWASec (Ajax Web Application Security) for coupling to avoid broken authentication and session management.

• Korean journal of communication and information
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• v.56
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• pp.156-174
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• 2011

Empathic concern is a major psychological factor which activates motives for help. This study investigates how the impact of empathic concern, as a personal trait, and the interaction with positive/negative framing influences responses towards help campaigns. Experiments with 176 subjects were conducted and the data were analyzed focusing on the role of anticipated emotions(satisfaction and guilt). The results were that people high in empathic concern showed larger anticipated satisfaction and behavioral intention compared to people low. The main effect was weak for anticipated guilt. Evidence suggests that anticipated satisfaction mediate the influence of the interaction of empathic concern and framing on behavioral intention. Anticipated guilt did not appear to act as an mediating variable. The theoretical and practical implications are discussed.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.6
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• pp.793-799
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• 2018

The CCD camera is easily deteriorated by radiation, and an integrated camera using an image pickup tube is used in a high radiation area. We implemented a radiation camera system which is divided into a camera head using radiation-resistant electronic components and a remote control using weak radiation-resistant electronic components such as TR, IC, etc. According to the experimental results, the first damage of the electronic parts was IC for horizontal and vertical sync generation, and it was confirmed that if the radiation of $2{\times}10^5{\sim}10^6rad$ is accumulated, the normal function is lost. In addition, the signal transmission cable for remoteization has added an input/output buffer circuit and reduced the closed loop area of the shield and the cable to eliminate signal loss correction and noise. Therefore, it is expected that the maintenance cost will be greatly reduced and practical because only the camera head part can be used instead of replacing the entire system.