• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.999-1008
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• 1996

The development and improvement of the originally designed direct rice sowing machine were carried out for the specific purpose of saving labor and increasing the efficiency of field operations in rice cultivation in the northern part of Japan. the prototype super wide spreader has a unique mechanism which propels rice seeds by compressed air and spreads them from the pivoting nozzle while the machine is in motion. The effective field capacity of sowing operation is about 6 ha/h. This spreader can also handle granular chemicals such as fertilizers, herbicides, pesticides and insecticides.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.10a
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• pp.345-357
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• 2011

Recently increasing eco-efficiency of natural dyeing has become an important topic. The purpose of this study was to manufacture colored Wall paper for interior materials by combining color therapy and natural dyeing. For this purpose, through experiments with water-bleed, K/S value and chroma changes of samples in Wall paper for interior materials.

• Geomechanics and Engineering
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• v.14 no.4
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• pp.325-336
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• 2018

Deformation of rock masses is not only related to rock itself, but also related to discontinuities, the latter maybe greater. Study on crack propagation at discontinuities is important to reveal the damage law of rock masses. DDARF is a discontinuous deformation analysis method for rock failure and some modified algorithms are proposed in this study. Firstly, coupled modeling methods of AutoCAD-DDARF and ANSYS-DDARF are introduced, which could improve the modeling efficiency of DDARF compared to its original program. Secondly, a convergence criterion for automatically judging the computation equilibrium is established, it could overcome subjective drawbacks of ending one calculation by time steps. Lastly but not the least, relationship between the super relaxation factor and the calculation convergence is analyzed, and reasonable value range of the super relaxation factor is obtained. Based on these above modified programs, influences on crack propagation of joint angle, joint parameters and geo-stresses' side pressure are studied.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.916-921
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• 1998

This study describes the result for the placement of the super flowing concrete(SFC) in under-pinning-top-slab which is located Inchon subway section 1-10 where, due to heavy reinforcements and limited working space, it was difficult to place concrete. After placing 600㎥, smooth construction and quality control were possible due to the good flow-ability, self-fillingability, and the resistance of segregation of the SFC itself. Furthermore, economical efficiency was obtained through not only the reduction of the works, labors, and site noise but also the efficient construction control. Because of the crack prevention, high strength, and a fine concrete surface, this study could be considered as a momentum to be adopted generally for applying the proposed method to the difficult subway construction area in the near future.

• Journal of Power Electronics
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• v.9 no.4
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• pp.575-581
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• 2009

In this paper two modes of operating a wound rotor induction machine as a generator at sub-and super-synchronous speeds in wind energy conversion systems are investigated. In the first mode, known as double fed induction generator (DFIG), the rotor circuit is fed from the ac mains via a controlled rectifier and a forced commutated inverter. Adjusting the applied rotor voltage magnitude and phase leads to machine operation as a generator at sub-synchronous speeds. In the second mode, the machine is operated in a slip recovery scheme where the slip energy is fed back to the ac mains via a rectifier and line commutated inverter. This mode is described as double output induction generator (DOIG) leading to increase the efficiency of the wind-to electrical energy conversion system. Simulated results of both modes are presented. Experimental verification of the simulated results are presented for the DOIG mode of operation, showing larger amount of power captured and better power factor when compared to conventional induction generators.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2064-2069
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• 2004

The main reason to analyze heat transfer in boiler inside through the performance test in fossil power plant is to increase plant high efficiency and energy saving movement in the government. Tins study intends to have trend and analyze the boiler heat transfer through the performance test, so it may give us the heat distribution in boiler inside in super-critical and sub-critica1 pressure type power plant

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1082-1089
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• 2017

Negative output elementary super lift Luo converter (NOESLLC), which has the significant advantages including high-voltage transfer gain, high efficiency, high power density, and reduced output voltage/inductor current ripples when compared to the traditional DC-DC converters, is an attractive DC-DC converter for the field of negative DC voltage applications. In this study, in consideration of the voltage across the energy transferring capacitor changing abruptly at the beginning of each switching cycle, the improved averaged model of the NOESLLC operating in continuous conduction mode (CCM) is established. The improved DC model and transfer functions of the system are derived and analyzed. The current mode control is applied for this NOESLLC. The results from the theoretical calculations, the PSIM simulations and the circuit experiments show that the improved DC model and transfer functions here are more effective than the existed ones of the NOESLLC to describe its real dynamical behaviors.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.119-125
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• 2002

The concept of dwelling space is tend to be changed not only to have reasonable mobility but also to have high quality of indoor air with psychologicaa satisfaction and comfortable. Moreover, recent constructed buildings have a big problem because of exhausted pollution gas and particles from building materials. More serious problem occurs from its high air tightness reducing the ventilation for saving the energy and superior adiabatic insulators to have high heat efficiency. Indoor air quality in super high-rise dwelling house was investigated by measuring pollutants such as $CO_2,=;CO,\;MO_2,\;R_n,\;TSP,\;PM_{10}$, HCHO, Offensive ordor. Subjective evaluation of residential environment is processed for the inhabitants who live in research space by testing environmental load in accordance with environment morphology, exterior environmental factor and post occupancy correlation and influence of attention.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.378-380
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• 2007

대화면 LCD TV (40인치 이상 LCD TV)에서 LCD 인버터의 가격 경쟁력을 위해 인버터 하나로 다수의 램프를 병렬 구동하면서 Two Stage System 구조인 Super IP Board 형태의 인버터 회로가 많이 사용되고 있다. 본 논문에서는 기존 Super IP Board의 인버터 구동 방식인 PWM 제어 방식을 분석하고, 문제점으로 제기되었던 Half-Bridge단 스위치의 하드 스위칭과 과도한 Circulating Energy 등의 문제를 해결한 새로운 Pulse Count Modulation (PCM) 방식을 적용한 인버터를 제안하고 이론적 및 실험적 검증을 통해 제안된 방식의 우수성을 확인하였다.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.814-819
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• 2006

This research is on the design and introducing of integrated thermal performance of super energy saying building, called 3 Liter house which can be sustained with 3 liter oil(kerosene) per $yr.m^2$. 3 liter houses(Passive houses) offer extended living comfort with only 15 to 20% of the space heating demand of conventional new building. To achieve this purpose, the efficiency of building components is improved, such as walls, windows or ventilation system and the construction technology is improved, such as the prevention of thermal bridge and the air tightness. The fuel cell is used as alternative energy. Energy consumption of 3L house is 2.08 [liter/$yr.m^2$] in monitoring result of $2006/2/1{\sim}2/7$ and ACH50 is 0.67 in result of Blow Door Test, therefore 3L House is well- insulated and well- airtighted house.