• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.8
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• pp.99-103
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• 2009

This paper presents equipment that can exchange watt-hour meters without outage for customers, It is simpler than other methods to avoid outage during exchange. Furthermore, it has protective function to ensure customer's facility from engineer mistake. Because of good point mentioned above, it can improve efficiency and safety. Adopting developed equipment can ensure continuous electric power supply to customers.

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.157-159
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• 2008

본 논문에서는 무선 전력 송신용 2400MHz 전력증폭기 설계에 대하여 기술한다. 비선형 설계 방법을 이용하여 먼저 1단 전력증폭기 모듈을 설계하였고, 이에 대한 측정을 통하여 전기적 특성을 확보한 후에 선형성에 대한 고려의 결과로써 3개의 모듈을 직렬 연결하여 3단 전력증폭기를 구성하였다. 제작된 전력증폭기는 선형적 동작 구간에서 25dB 이상의 높은 이득과 1Watt 근처의 출력특성을 보였는데, 30dBm의 출력전력에서 23%의 효율 특성을 나타내었다.

• Kyungpook Mathematical Journal
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• v.56 no.3
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• pp.831-844
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• 2016

In this paper, we consider a discrete predator-prey system with Watt-type functional response and impulsive controls. First, we find sufficient conditions for stability of a prey-free positive periodic solution of the system by using the Floquet theory and then prove the boundedness of the system. In addition, a condition for the permanence of the system is also obtained. Finally, we illustrate some numerical examples to substantiate our theoretical results, and display bifurcation diagrams and trajectories of some solutions of the system via numerical simulations, which show that impulsive controls can give rise to various kinds of dynamic behaviors.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.262-264
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• 2003

This paper develops an ADWHM(Advanced Digital Watt Hour Meter) based on RISK type'8bit micro-controller, which has voltage management data recording function, load management data recording function as well as the existing watt-hour data recording data function. It can enhance greatly the economics of the existing remote meter reading system. Also it can improve highly the quality of power supplied to the electric customer by minimizing the voltage management cost and by enhancing the efficiency of load management.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.8
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• pp.364-369
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• 2005

This paper deals with an automatic optimum design based on a rated output for a synchronous reluctance motor (SynRM). The focus of this paper is the motor design relative to the output power on the basis of rotor shape of a SynRM in each rated watt. And optimization algorithm is used by means of sequential unconstrained minimization technique(SUMT). The coupled Finite Elements Analysis (FEA) & Preisach model have been used to evaluate nonlinear solutions. The proposed procedure allows to define the rotor geometric dimensions according to rated watt starting from an existing motor or a preliminary design.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2526-2528
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• 2001

본 논문은 Full bridge 방식의 LC 병렬구조를 갖는 400watt HID용 전자식 안정기 구조에 대한 해석과 항상 HID 램프가 일정한 출력을 갖도록 하는 제어 방법에 대해 다루었다. 전자식 안정기의 구조는 LC 병렬구조이다. 램프에 흐르는 전류값에 따라서 전자식 안정기의 동작주파수가 가변되는 구조를 가지고 있어, 램프 점등 초기에는 동작 주파수가 높다가 안정상태로 들어가면 주파수가 떨어지는 특성을 지니고 있다.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.3
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• pp.19-23
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• 2015

In this study, two types of Au/TiW bump samples were fabricated by the electroplating process onto Al/Si and SiN/Si wafers for the COG (Chip On Glass) packaging. TiW was used as the UBM (Under Bump Metallurgy) material of the Au bump and it was deposited by a sputtering method under the sputtering powers ranges from 500 to 5000 Watt. We investigated the delamination phenomenas for the prepared samples as a function of the input sputtering powers. The stable interfacial adhesion condition was found to be 1500 Watt in sputtering power. In addition, the SAICAS (Surface And Interfacial Cutting Analysis System) measurement was used to find the adhesion strength of Au bumps for the prepared samples. TiW UBM films were deposited at the 1500 Watt sputtering power. As a results, there was a similar adhesion strengths between TiW/Au interfacial films on Al/Si and SiN/Si wafers. However, the adhesion strength of TiW UBM sputtering films on Al and SiN under films were 2.2 times differences, indicating 0.475 kN/m for Al/Si wafer and 0.093 kN/m for SiN/Si wafer, respectively.

• Journal of the Korean Geotechnical Society
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• v.21 no.6
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• pp.41-52
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• 2005

Because the allowable current loading of buried electrical transmission cables is frequently limited by the maximum permissible temperature of the cable or of the surrounding ground, there is a need fur cable backfill materials that can maintain a low thermal resistivity even while subjected to high temperatures for prolonged periods. Temperatures greater than $50^{\circ}C\;to\;60^{\circ}C$ may lead to breakdown of cable insulation and thermal runaway if the surrounding backfill material is unable to dissipate the heat as rapidly as it is generated. This paper describes the results of studies aimed at the development of backfill material to reduce the thermal resistivity. A large number of different additive materials were tested to determine their applicability as a substitute material. Tests were carried out for Dongrim river sand, a relatively uniform sand of very high thermal resistivity, $50^{\circ}C-cm/watt\;at\;10\%$ water content, $260^{\circ}C-cnuwatt$ when dry, and Jinsan granite screenings, and D-2 (sand and granite screenings mixture), E-1 (rubble and granite screenings mixture), a well-graded materials with low thermal resistivity, about $35^{\circ}C-cm/watt$ when at 10 percent water content, $100^{\circ}C-cm/watt$ when dry. Based on this research, 3 types of backfill materials were suggested for improved materials with low thermal resistivity and the applicability was assessed through field tests.

• Journal of the Korean Geosynthetics Society
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• v.10 no.4
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• pp.113-121
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• 2011

River sand has generally used for the backfill material of underground power cables. The thermal resistivity of it has $150^{\circ}C$-cm/Watt in wet condition and more than double in dry condition. The final goal of this study is to find the backfill material which has a small change in thermal resistivity with various water contents, for example thermal resistivity is $50^{\circ}C$-cm/Watt and $100^{\circ}C$-cm/Watt in wet and dry conditions respectively. In this study it is presented that the comparison of thermal resistivity using stone powder, crush rock, weathered granite soil and Jumunjin sand as well as river sand in the needle method regarding water content, dry unit weight and particle size distribution. As a result, the thermal resistivity of a material is minimized when they have maximum dry unit weight at optimum moisture content and maximum density by appropriately mixing materials for particle size distribution. Therefore thermal resistivity characteristics should be considered two factors: one is the difference between natural dry condition and dry state after optimum moisture content, and the other is the difference between unit weight of raw material and maximum dry density.

• Journal of Navigation and Port Research
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• v.26 no.1
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• pp.22-27
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• 2002

The 25 Watt hybrid MIC SSPA has been developed in the frequency rang from 1.6265 GHz to 1.6465 GHz for uplink of INMARST's earth station. To simplify the fabrication process, the whole system is designed of two parts composed of a friving amplifier and a power amplifier. The Motorolas MRF-6401 is used for driving part, the Motorolas MRF-16006 and MRF-16030 is used the power amplifier. We reduced weight and volume of high power amplifier through arranging the bias circuits in the same housing. The realized SSPA has more than 30 dB for gain within 20 MHz bandwidth, and the voltage standing wave ratios(VSWR) of input and output port are less than 1.7, respectively. The output power of 44 dBm is achieved at the 1 dB gain compression point of 106365 GHz These results reveal a high power amplifier of 25 Watt which is the design target. The Proposed SSPA manufacture techniques in this paper can be applied to the implementation of high power amplifiers for some radars and SCPC.