• Korean Journal of Optics and Photonics
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• v.23 no.1
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• pp.36-41
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• 2012

Total external reflection (TER), which does not occur on a dielectric interface, is a unique feature of surface plasmon-polaritons (SPP). We propose an SPP-TER waveguide structure consisting of low-index dielectric nanocore covered with high-index dielectric on a flat metal surface. The SPP mode confined in the nanocore by the TER effect has a mode size much smaller than wavelength scale. Numerical comparison of mode characteristics between the SPP-TER waveguides and other total-internal-reflection-based waveguides such as metal or high-index dielectric nanowires show that the SPP-TER structures can possess higher modal gain for applications of nanocavity lasers.

• Journal of the Korean Society of Safety
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• v.30 no.4
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• pp.135-141
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• 2015

At the end of 2014, ordering organizations, 25 general contractors and 80 specialty contractors were certified by the KOSHA 18001 for the establishment of safety & health management system. However, safety management departments in the certified companies have been disrupted due to the financial difficulty and CEO's indifference, which has resulted in the cancellation of more than 30% of the certifications. Furthermore, the KOSHA 18001 due to the shortage of internal evaluators in KOSHA and the increase of applications for new certification & the extension of the certification is placed in a difficult situation in the near future. Therefore, it is necessary to enhance the KOSHA 18001 by solutions such as introducing outside evaluators, which is the key point of this study. This study was performed through the questionnaire survey & the interviews with the construction companies, ordering organization and KOSHA 18001 specialists The content is centered on the introduction of external evaluators. As a result, the introduction of external evaluators is necessary through amending certification regulation because only internal evaluators cannot afford to process all the new application and the extension of existing certifications.

• 연구논문집
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• s.28
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• pp.73-87
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• 1998

A pneumatic control system of compressed air as a working fluid has a variety of advantages such as low price, high respondence, non-explosion and good control performance and thus has many applications in the field of automobile, electronic and semiconductor industry. However, it has a difficulty in contolling a precise position due to quick response of system and compressibility of working fluid and. in particular, shock stress may occur due to an external load, resulting in fracture of a cylinder cap unless cushion device is equipped in the linear actuator. To avoid this, a cushion device should be installed for damping effect of the external load and the supply pressure as well as for decreasing shock stress and vibration caused by high speed rotation. Previous studies include dimensionless analyses and computer simulations of cushion capability and experiments of horizontally-mounted cylinder performances. A new attempt is experimentally made in this study using a vertically-mounted cylinder under an operation condition of 4, 5 and 6 (bar) as supply pressure and 40, 70 and 100 (kgf) as external load. It turns out that the cushion pressure is mainly a function of the external load rather than the supply pressure. The cushion characteristics was also revealed in the meter-in circuit.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.389.2-389.2
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• 2016

The flexible solid state device has been widely studied as portable and wearable device applications such as display, sensor and curved circuits. A zero-bias operation without any external power consumption is a highly-demanding feature of semiconductor devices, including optical communication, environment monitoring and digital imaging applications. Moreover, the flexibility of device would give the degree of freedom of transparent electronics. Functional and transparent abrupt p/n junction device has been realized by combining of p-type NiO and n-type ZnO metal oxide semiconductors. The use of a plastic polyethylene terephthalate (PET) film substrate spontaneously allows the flexible feature of the devices. The functional design of p-NiO/n-ZnO metal oxide device provides a high rectifying ratio of 189 to ensure the quality junction quality. This all transparent metal oxide device can be operated without external power supply. The flexible p-NiO/n-ZnO device exhibit substantial photodetection performances of quick response time of $68{\mu}s$. We may suggest an efficient design scheme of flexible and functional metal oxide-based transparent electronics.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.134-144
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• 2017

This paper presents an adaptive control strategy for the speed control of a four-phase switched reluctance motor (SRM) in automotive applications. The main objective is to minimize the torque ripples, despite the unstructured uncertainties, time-varying parameters and external load disturbances. The bound of perturbations is not required to be known in the developing of the proposed adaptive-based control method. In order to achieve a smooth control effort, some properties are incorporated and the proposed control algorithm is constructed using the Lyapunov theorem where the closed-loop stability and robust tracking are ensured. The effectiveness of the proposed controller in rejecting high perturbed load torque with smooth control effort is verified with comparing of an adaptive sliding mode control (ASMC) and validated with experimental results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.51-56
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• 2010

AC loss is main issue for power applications using YBCO coated conductor. The striated YBCO CC(Coated Conductor) has been proposed by several researchers to decrease a magnetization loss. A continuously transposed coated conductor (CTCC), suggested by our research group before, could be very useful for lower magnetization loss of large current power applications. In this paper, an AC loss reduction effect by the stack, striation and transposition of YBCO CCs under a time varying external magnetic field. To estimate the reduction effects for perpendicular magnetization loss, several CTCC samples were prepared and tested. Also, we measured angular dependency of magnetization losses of various CTCC samples.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.7
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• pp.563-566
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• 2009

This paper presents a motor drive IC for automotive applications. The drive IC is dedicated to control and drive external MOSFETs which directly drive 3-phase motor with a high current. In case of driving high-side power switches, the bootstrap topology is widely used. however, it requires three bootstrap diode and three capacitor respectively. And it needs a minimum charging time to maintain high-side voltage. The motor drive IC uses a charge-pump circuit for all three high-side voltage with various protection schemes for automotive applications.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.304-307
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• 2015

Virtualization lacks capabilities for enabling the application to scale efficiently because of new applications components which are raised to be configured on demand. In this paper, we propose an architecture that affords mobile app based on nomadic smartphone using not only mobile cloud computing-cloudlet architecture but also a dedicated platform that relies on using virtual private mobile networks to provide reliable connectivity through Long Term Evolution (LTE) wireless communication. The design architecture lies with how the cloudlet host discovers service and sends out the cloudlet IP and port while locating the user mobile device. We demonstrate the effectiveness of the proposed architecture by implementing an android application responsible of real time analysis by using a vehicle to applications smart phones interface approach that considers the smartphones to act as a remote users which passes driver inputs and delivers outputs from external applications.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.223-227
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• 2003

A new flexible electronic packaging technology and its medical applications are presented. Conventional silicon chips and electronic modules can be considered as "mechanically rigid box." which does not bend due to external forces. This mechanically rigid characteristic prohibits its applications to wearable systems or bio-implantable devices. Using current MEMS (Microelectromechanical Systems) technology. a surface micromachined flexible polysilicon sensor array and flexible electrode array fer neural interface were fabricated. A chemical thinning technique has been developed to realize flexible silicon chip. To combine these techniques will result in a realization of truly flexible sensing modules. which are suitable for many medical applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.41-42
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• 2009

This paper presents a motor drive IC for automotive applications. The drive IC is dedicated to control and drive external MOSFETs which directly drive 3-phase motor with a high current. In case of driving high-side power switches, the bootstrap topology is widely used. However, it requires three bootstrap diode and three capacitor respectively. And it needs a minimum charging time to maintain high-side voltage. The motor drive IC uses a charge-pump circuit for all three high-side voltage with various protection schemes for automotive applications.