• 한국연소학회:학술대회논문집
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• 한국연소학회 2013년도 제46회 KOSCO SYMPOSIUM 초록집
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• pp.83-85
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• 2013

With an increase in the use of low rank coals in power plants, various operational issues were raised in the fuel storage and supply, combustion, boiler and flue gas treatment systems. In the fuel storage and supply system, the main issue is the self-heating propensity of low rank coals leading to spontaneous combustion in yard storage, transport and pulverization. This study evaluated the reactivity of various sub-bituminous and bituminous coals with oxygen at low temperatures by analyzing the temperature increase characteristics of coals under a constant flow rate of oxygen supply. The results were quantified to a self-heating index and the relation with the fuel properties were evaluated.

• Journal of Power Electronics
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• 제8권2호
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• pp.192-199
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• 2008

This paper is mainly concerned with a high frequency soft-switching PWM inverter suitable for consumer induction heating systems. The proposed system is composed of a soft switching chopper based boost PFC converter stage with passive snubber and phase shifted PWM controlled full bridge ZVZCS high frequency inverter stage. Its fundamental operating performances are illustrated and evaluated in the experimental results. Its effectiveness is substantially proved on the basis of the experimental results from a practical point of view.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1205-1210
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• 2004

The 4-20mA analog signal used in the various industrial fields to interface sensor in distributed process control has been replaced with relatively simple digital networks, called "fieldbus, and recently by Ethernet. Significant advances in Internet and computer technology have made it possible to develop an Internet based control, monitoring, and operation scheduling system for heating, ventilation and air-conditioning (HVAC) systems. The seamless integration of data networks with control networks allows access to any control point from anywhere. Field compatible field devices become so-called "smart" devices, capable of executing simple control, diagnostic and maintenance functions and providing bidirectional serial communication to higher level controller. The most important HVAC of BAS has received nationwide attention because of higher portion of more than 40% in building sector energy use and limited resources. This paper presents the Internet-based monitoring and control architecture and development of LonWorks control modules for AHU (air handling units) of HVAC in viewpoint of configuring BAS network. This article addresses issues in architecture section, electronics, embedded processors and software, and internet technologies.

• 대한기계학회논문집
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• 제8권1호
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• pp.1-9
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• 1984

In the utilization of solar energy most often a flat solar collector is used for solar heating, system. Since solar energy is absorbed through this solar collector, it is considered to be a most important part in the whole solar heating system. The purpose of the present investigation is to evaluate the influence of varying design parameters for thermal performances of flat-plate solar collector. By analysing these parameters, optimum design of solar collector would become possible. Specification of the existing solar collector are utilized in calculation as a starting point. Analysis is carried out numerically for "Unit Solar Collector" which is composed of fin and tube. Among design parameters. such parameters as mass flow rate per unit area, tube spacing and fin thickness are selected as variables in the computer simulation model. Results are presented for thermal performances of flat-plate solar collector for each important design parameters, so that predictions become possible through numerical analysis without performing experiments whenever it is required. required.

• 한국주거학회논문집
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• 제10권1호
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• pp.75-84
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• 1999

The purpose of this study is to identify the characteristics of the thermal environment, and to analyze the relationship between the thermal reactions and the skin temperatures in the lying position in the radiant floor heating system. The results are as follows: 1) The globe temperature was nearly equal to the operative temperature in the room. 2) The floor surface temperature and the globe temperature were 26.4$^{\circ}C$ and 23.6$^{\circ}C$, respectively when the whole body temperature was at neutral point. 3) The mean temperature of the six skin parts was 31.3$^{\circ}C$ (cold thermal environment); 34.1$^{\circ}C$ (neutral thermal environment); 35.1$^{\circ}C$ (hot thermal environment).

• 설비공학논문집
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• 제19권1호
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• pp.77-85
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• 2007

One of the most common approaches to achieve better thermal comfort with the radiant floor heating system is supply water temperature control, which is that supply water temperature is varied with outdoor air temperature. But the application of this control method was not easy, because there has been no way to determine the supply water temperature. So in this study, a comprehensive, yet simple calculation method to find out the required supply water temperature is suggested by combining the building heat loss equation and the heat emission model of hydronic radiant floor heating system for single zone. And then using this calculation method, the multizone control method is suggested and confirmed through the thermal simulation. It is shown that indoor air temperature is stably maintained around the set point.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1776-1779
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• 2002

In this paper, we measured the heating time on the key measuring point of the meridian of the human body's left and right by using heating machine. Then, based on the fuzzy theory, this study diagnosed the each meridian's strength and weakness, After that, both the strengthening and weakening stimulus of magnetic field was applied to the dominant direction to find out how the degree of strength and weakness of the meridian changed. Ultimately, the magnetic therapy that can stimulate the magnetic field at the time of diagnosis and thereby balancing the interactive of a five system has been materialized. For the stimulation of magnetic field, a stimulating device which can change the direction and time on a specific part of the key measuring points has been developed and used. The therapeutic method is as follows. first, the strength and weakness of the meridian has been determined. Second, both the extremely weak meridian of Yin(Shade) and Yang(Shine), and the extremely strong meridian of Yin and Yang were adjusted by applying appropriate ascending and descending stimuli respectively.

• 한국지열·수열에너지학회논문집
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• 제11권1호
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• pp.7-14
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• 2015

This study has been purposed to provide thermal comfort range in accordance with the residential style of radiant floor heating space, and to compare it with the thermal comfort range at predicted mean vote. The survey for the thermal sensation vote to the subjects and the measurement of environmental factors has been executed, and regression analysis has been performed. It is interpreted that the combination of the physical factor and the psychological factor results lower neutral point of the floor sitting style than that of the chair sitting style. There are some difference between the measured predicted mean vote and the thermal sensation vote via survey, which appears to be caused by distinctive heat transfer characteristic of floor radiant heating space, such as, high radiant temperature and contact thermal sensation of floor surface.

• 전력전자학회논문지
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• 제7권1호
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• pp.48-54
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• 2002

본 논문에서는 간접 유도가열 되는 DPH시스템과 주파수 범위가 20kHz에서 50kHz사이에서 작동되는 전압형 직렬공진 고주파인버터를 이용하여 열 기체를 발생시키는 전압형 공진형 인버터에 관하여 설명하였다. 얇은 스텐레스 판재가 서로 스폿 용접되어 연결되어 있고 미세한 많은 구멍을 갖고있는 적층형 충진발열테로 특수하게 설계된 유도 가열기는 외부에 워크 코일로 감겨져 있는 불소수지계의 절연용기 안에 삽입되어 있다. 이 워크 코일은 공진형 인버터와 연결되어 있으며 유도가열기를 통해 흐르는 관 유체를 1단가열부에서 저압의 포화증기를 2단가열부에서 열방사성 증발유체를 생성하는 본 DPH시스템의 성능 및 효용성을 실용적인 측면에서 논의하고 평가 할 것이다.

• 대한조선학회논문집
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• 제46권6호
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• pp.675-687
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• 2009

In general, the forming process of the curved hull plates consists of sub tasks, such as roll bending, line heating, and triangle heating. In order to complement the automated curved hull forming system, it is necessary to develop an algorithm to classify the curved hull plates of a ship into standard shapes with respect to the techniques of forming task, such as the roll bending, the line heating, and the triangle heating. In this paper, the curved hull plates are classified by four standard shapes and the combination of them, or saddle, convex, flat, cylindrical shape, and the combination of them, that are related to the forming tasks necessary to form the shapes. In preprocessing, the Gaussian curvature and the mean curvature at the mid-point of a mesh of modeling surface by Coon's patch are calculated. Then the nearest neighbor method to classify the input plate type is applied. Tests to verify the developed algorithm with sample plates of a real ship data have been performed.