• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.606-607
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• 2008

환경문제에 대한 관심이 전 세계적인 이슈로 고조됨에 따라 여러 산업의 패러다임에도 큰 변화가 요구되고 있다. 특히 지구 온난화 문제의 심각성에 의해 선진국을 주축으로 온난화의 주범인 화석연료 사용을 줄이려는 노력이 나타나고 있다. 이에 따라 화석연료를 주로 사용하는 전력산업에서도 친환경적 에너지인 신재생에너지를 보급하기 위한 노력들이 늘어나고 있다. 따라서 본 논문은 신재생에너지를 포함한 분산전원을 효과적으로 운영할 수 있는 마이크로그리드 시스템의 관점에서 환경비용 및 운용방식을 고려한 경제성 평가를 시행하였다. 경제성 평가는 여러 가지 경우를 고려하여 최적화 프로그램인 GAMS를 이용하여 모의하였다.

• Journal of the Korea Society of Computer and Information
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• v.9 no.3
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• pp.127-133
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• 2004

This study was carried out develope a temperature control system of temperature control by used K-thermocouple. This system was producted a stable voltage regulator 22Bit of digital converter and 22Bit of resolution. It was producted a micro voltage of 25 times amplification and controlled a DC0.1V~DC4.7V within 0～120$0^{\circ}C$. We designed block-diagram of hardware and software by PIC16C74 in a micro-controller, we are made up of a VFD function and can be used interface of a power block.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.80-82
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• 2008

This paper deals with the design of an 870 krpm class high-speed permanent magnet synchronous generator (PMSG) applied to micro turbine system. Since space where the high-speed PMSG coupled with the micro turbine occupies in the system is strictly limited, the work described in this paper is motivated by the desire to make maximum output power of the generator considering the rotor and stator structures, winding methods and bearing system under restricted space.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.24-27
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• 2003

This paper discusses practical strategies for transition from a pinching to a power grasping, where a multi-fingered hand mounted on a robotic arm envelops a cylindrical object on a table. When the manipulation system grasps a cylindrical object like a pen on a desk, a complete enveloping is not impossible in the initial configuration. The system firstly pinches the object only with two or three fingers and then grasp it with fingers and a palm after regrasping. In this pinching-grasping transition maneuver, human unconsciously selects proper strategy according to some conditions including object dimensions and initial pinching positions. In this paper we therefore develop six possible strategies for this pinching-grasping transition and then investigate their performances for some objects with various dimensions and various grasping positions, using numerical simulations. Based on their results, effective strategies are implemented by using a hand-arm system.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.649-651
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• 1999

This paper presents SNMP remote management system for power plants using micro-controller. Control board supporting LAN-based remote monitor and control is produced and MMI program on PC is also constructed. To expand into Internet, SNMP(Simple Network Management Protocol), the standard network management protocol of TCP/IP protocol suite, is ported to this control board consisted of micro-controller, 80c196KC, and LAN controller, Am7990DC. To overcome the constraints of CPU performance and memory capacity, TCP/P protocol suite is simplified and informations needed to management were implemented in accordance with MIB(Management Information Base) specified in RFC. Also monitoring software is constructed by Visual Basic.

• Journal of Power System Engineering
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• v.19 no.3
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• pp.55-62
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• 2015

This paper discusses a new model for investigating the micro-mechanical behavior of beam-like structures composed of various elastic moduli and complex geometries varying through the cross-sectional directions and also periodically-repeated along the axial directions. The original three-dimensional problem is first formulated in an unified and compact intrinsic form using the concept of decomposition of the rotation tensor. Taking advantage of two smallness of the cross-sectional dimension-to-length parameter and the micro-to-macro heterogeneity and performing homogenization along dimensional reduction simultaneously, the variational asymptotic method is used to rigorously construct an effective zeroth-order beam model, which is similar a generalized Timoshenko one (the first-order shear deformation model) capable of capturing the transverse shear deformations, but still carries out the zeroth-order approximation which can maximize simplicity and promote efficiency. Two examples available in literature are used to demonstrate the consistence and efficiency of this new model, especially for the structures, in which the effects of transverse shear deformations are significant.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.534-535
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• 2006

This study attempts to develope the micro-turbine generators which is expected to run efficiently even in very low head and small flow rate, so that the limitations on the conventional small scale hydropower could be alleviated and competition with other alternative energy sources in the changable design conditions could be attained. The micro turbine generator of a new concept was designed based on changable design conditions, hydrodynamics and theory of power transmission.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.7
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• pp.351-363
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• 2001

This paper presents an experimental investigation on the heat trensfer characteristic of micro pipe (MHP) array with 38 triangular microgrooves. A heat pipe is an effective heat exchanger operating without external power. The heat pipe transfers heat by means of the latent heat of vaporization and two-phase fluid flow driven by the capillary force. The overall size of the MHP array can be put undermeath a microelectonic die and integrated into the electrronic package of a microelectronin device to dissipate the heat from the die. The MHP array is fabricated by micromachining with a silicon wafer and a glass substrate. The MHP was filled with water and sealed. The experimental results show the temperature decrease of 12.1$^{\circ}C$ at the evaporator section for the input power of 5.9 W and the improvement of 28% in the heat transfer rate.

• Communications for Statistical Applications and Methods
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• v.10 no.1
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• pp.211-224
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• 2003

Good's lambda test, a permutation test used to detect the changes of microorganism composition under two pathological conditions, has been quite popular for studying the micro-flora responsible for periodontal disease. A vast number of different micro-flora in the mouth renders the traditional chi-square test inapplicable. The main purpose of this paper is to evaluate the power of this test so that the sample size can be determined at the design stage. The robustness of this test and its comparison to two other intuitive tests are also presented. It is found that a permutation test based on likelihood ratio is more powerful than the lambda test in our simulated cases.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.185-185
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• 2014

In this study, we investigated surface characteristics of hydroxyapatite coated surface on nano/micro pore structured Ti-35Ta-xNb alloys. This paper was focus on morphology and corrosion resistance of Anodic oxidation. To prepare the samples, Ti-35Ta-xNb (x= 0, 10 wt. %) alloys were manufactured by arc melting and heat-treated for 12 h at $1050^{\circ}C$ in Ar atmosphere at $0^{\circ}C$ water quenching. Micro-pore structured surface was performed using anodization with a DC power supply at 280 V for 3 min, nanotube formed on Ti-35Ta-xNb alloys was performed using DC power supply at 30 V in 60 min at room temperature. Surface morphology and structure were examined by field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction.