• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.438-442
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• 2001

Much attention has given to EMI effects created by variable speed ac drive system. This paper focuses on the switching technique to mitigate common mode voltage. Zero switching states of inverter control invoke large common mode voltage. Using inversed carrier wave, zero switching states are removed. In addition, proposed technique is easy to apply to existing 2-level inverter design. And common mode mitigation technique for sinusoidal PWM is also presented. Proposed switching technique is implemented with a 2.2kw 1735rpm induction motor.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.427-434
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• 2000

When a large number of hazardous road cut-slopes are spreaded in widely scattered areas, the effective investigation and evaluation method that is able to decide the risk of hazardous road cut-slopes, is required. Many different evaluation techniques were suggested by many different researchers based on their demands, but there are the limited researches on the experimental evaluation technique which can be utilized by personnel who does not have much experiences on the road cut-slopes. In this study, the appropriate and effective evaluation method of the dangerous slope is suggested and this method can be used by both inexperienced and experienced persons. Therefore, this is the one of the effective ways that can mitigate the possibility of landslides.

• ETRI Journal
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• v.36 no.3
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• pp.367-373
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• 2014

With high bandwidth, low interference, and low power consumption, optical network-on-chip (ONoC) has emerged as a highly efficient interconnection for the future generation of multicore system on chips. In this paper, we propose a new path-setup method for ONoC to mitigate contentions, such as packets, by recycling the setup packet halfway to the destination. A new, strictly non-blocking $6{\times}6$ optical router is designed to support the new method. The simulation results show the new path-setup method increases the throughput by 52.03%, 41.94%, and 36.47% under uniform, hotspot-I, and hotspot-II traffic patterns, respectively. The end-to-end delay performance is also improved.

• Korean Journal of Childcare and Education
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• v.15 no.6
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• pp.169-188
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• 2019

Objective: The purpose of the present study was to examine the mediating role of career calling in the relationship between job stress and burnout as well as the association among job stress, career calling, and burnout. Methods: A sample of three-hundred and seven child care teachers in the metropolitan area of Seoul completed questionnaires on job stress, career calling, and burnout. Results: Correlation and regression analyses indicated that lack of directors' leadership and administrative support, work overload, and career calling significantly predicted child care teachers' burnout. Moreover, the association of lack of directors' leadership and administrative support of burnout was mediated by career calling. Conclusion/Implications: The findings suggest that directors' leadership and seamless administrative support need to be emphasized in order to reduce burnout and mitigate work-related stress among child care teachers. The findings also highlight the important role of career calling in reducing burnout among child care teachers and suggest the consideration of career calling as a target in interventions and educational programs.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.2
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• pp.324-330
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• 2012

In this paper, we presents a robust control system design for compensating hysteresis of a piezoelectric actuator-based actuation unit. First, the dynamics between the input voltage and the output displacement of the actuation unit are unravelled via a non-parametric system identification method. From the dynamic characteristics of those experimental transfer functions, a parametric model is then derived, whose dynamics match those of the non-parametric ones under various conditions on input voltages. A robust controller is constructed on the basis of this parametric model in order not only to effectively compensate the hysteresis of the actuation unit but also to guarantee the robust stability. Extensive experiments show that the proposed robust control system successfully mitigate the effect of the hysteresis and improve the tracking capability of the actuation unit.

• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.1
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• pp.33-54
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• 2010

Providing a secure 3-tier Web application has become a high priority for companies as e-businesses have increased the amount and the sensitivity of corporate information that can be accessed through the web. Web applications become more difficult to secure with this very increase in online traffic and transactions. This paper first reviews the 3-tier of web application, types of attacks that can threaten web application services and security principles. We then are designing and implementing a secure web application with open source software that able to mitigate the web application vulnerable to attack.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.11
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• pp.2928-2940
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• 2013

Key exposure is a major threat to secure cryptosystems. To mitigate the impact caused by key-compromise attacks, a key-insulated cryptographic mechanism is a better alternative. For securing the large message communication in peer-to-peer networks, in this paper, we propose the first novel identity-based key-insulated encryption (IB-KIE) scheme with message linkages. Our scheme has the properties of unbounded time periods and random-access key-updates. In the proposed scheme, each client can periodically update his private key while the corresponding public one remains unchanged. The essential security assumption of our proposed scheme is based on the well-known bilinear Diffie-Hellman problem (BDHP). To ensure the practical feasibility, we also formally prove that the proposed scheme achieves the security requirement of confidentiality against indistinguishability under adaptive chosen-ciphertext attacks (IND-CCA2) in the random oracle model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.2
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• pp.906-918
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• 2018

The advent of the Internet of Things (IoT) technology, which brings many benefits to our lives, has resulted in numerous IoT devices in many parts of our living environment. However, to adapt to the rapid changes in the IoT market, numerous IoT devices were widely deployed without implementing security by design at the time of development. As a result, malicious attackers have targeted IoT devices, and IoT devices lacking security features have been compromised by attackers, resulting in many security incidents. In particular, an attacker can take control of an IoT device, such as Mirai Botnet, that has insufficient security features. The IoT device can be used to paralyze numerous websites by performing a DDoS attack against a DNS service provider. Therefore, this study proposes a scheme to minimize security vulnerabilities and threats in IoT devices to improve the security of the IoT service environment.

• The Journal of Internal Korean Medicine
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• v.24 no.4_2
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• pp.995-1006
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• 2003

Objective: The purpose of this study is to see whether pain in cancer patients is decreased by Eriobotryae Folium Fomentation. Methods: We examined the change in pain among six cancer patients, prescribing Eriobotryae Folium Fomentation. As for evaluating methods, we used the case history of pain, the direct evaluation of pain, the indirect evaluation of pain. The direct evaluation of pain is subdivided by the language expression, the non-language expression, and Visual analog scale(VAS). The indirect evaluation of pain is subdivided by the condition of walking, mood and the condition of sleep. Results: After two weeks, any remarkable pain decrease is not observed in both of the direct evaluation and indirect evaluation.

• Transactions of Materials Processing
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• v.22 no.1
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• pp.42-47
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• 2013

The bicycle is one of the most important eco-friendly transport methods which can mitigate global warming. The portability of a bike on public transportation systems is essential for the wide spread use of bicycles by people in urban environments. In this study, a lightweight urban folding bike was developed with careful consideration of the association with public transport. A folding frame using a moving slide link mechanism made from AL6061 is proposed. Numerical analysis was conducted to evaluate structural safety of the bike in both vertical and pedal loading tests. The proposed urban folding bicycle weights only 10kg and summation of its width, length, and height in the folded configuration is under 158cm.