• Transactions of Materials Processing
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• v.8 no.1
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• pp.65-77
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• 1999

In recent years, the quality requirements from the customers of hot rolled steel strip have been steadily increasing in diversity and strictness. To meet these quality requirements as well as to improve productivity, steel mills have been doing their efforts for developing high performance Automatic Gauge Control (AGC) system. However, it is very time consuming and also needs a lot of money to develop the new technologies of AGC in actual mill. So, there has been a demand for developing the Dynamic Hot Rolling Simulator since late 80's. It is a kind of software packages and can analyze the dynamic behaviors of hot finishing rolling process without laborious experiments in actual mill. It can also be used as a designing tool of Automatic Gauge Controller. In this work, the Dynamic Hot Rolling Simulator which is applicable to 6 sands hot strip mill rolling was developed. The MATLAB with SIMLINK was used as a software developer for making the main part of simulator because it is very powerful tool for modeling, integrating, controller design, and simulation. In this paper, the structures and the mathematical models of the simulator were briefly described and the results of simulation on the transient phenomena of hot rolling process with actual mill data were also presented.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.281-285
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• 2009

This paper is to simulate a solar hot water heating system used in a medium-scale office building using the dynamic simulation. This study is focused chiefly on the annual variation of energy performance, the solar fraction with respect to the difference of hot water load temperature. For this purpose the simple model of a solar hot water heating system has been considered with TRNSYS program and the simulations were performed with the weather data in Seoul, Korea. The share ratio of solar hot water system of the summer season appeared higher than the winter season because that the decrease of the domestic hot water load was far despite the relative decrease of the solar radiation. As the temperature was lower from $60^{\circ}C$ to $50^{\circ}C$, the solar fraction increases 8.1 percent due to 20-percent decrease of annual hot water load.

• The Journal of Engineering Geology
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• v.30 no.3
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• pp.379-397
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• 2020

In this study, Long-term change of water quality in Donrae Hot Spring was characterized using water quality data from 1922 to 2019. According to Mann-Kendall analysis and Sen's slope using long-term water quality data of Dongnae Hot Spring from 1922 to 2019, temperature, Ca, SiO₂, and HCO₃ show an increasing trend whereas EC, Na, K, Mg, Cl, and SO₄ show a decreasing trend or negligible trend. In addition, the water type of Dongnae Hot Spring stably belongs to Na-Cl type over time. The spatial distributions of water temperature and chemical constituents in 2004, 2009, 2014, and 2019 show variable patterns with showing some difference depending on sampling locations in different years. These results indicate that despite the long-term pumping of the hot spring water, the water quality is quite stable during the entire study period.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.2
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• pp.117-129
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• 2008

Data synchronization between data stored in mobile communication terminals and data in a central server is one of essential tasks for efficient mobile communication environments. Since, however, manufacturers of mobile terminals have their proprietary data synchronization mechanisms, data interoperability can hardly be achieved. In this paper, an integrated data synchronization gateway based SyncML is designed and implemented. SyncML data synchronization is one of open standards proposed by OMA(Open Motile Alliance). In other words, by constructing a data synchronization gateway which can transform various proprietary data into SyncML data and vice versa, data interoperability between mobile terminals which use different data synchronization mechanisms can be achieved. With an integrated data synchronization gateway system implemented in this work, interoperability among WinCE-based ActiveSync data, PalmOs-based HotSync data and OMA SyncML data can be achieved.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.90.1-90.1
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• 2015

Almost hot-Super Earths ($R_p$~1 to $4R_{earth}$ orbital period < 100 days) are around Sun-like stars. But our solar system does not have hot-Super Earth. Andre et al. 2015 has explained this phenomenon by that Jupiter blocks migration of super earth. We have found a multi-planetary system KOI-94 with exo-Jupiter and hot-Super Earth from NASA exoplanet archive data (http://exoplanetarchive.ipac.caltech.edu). In this study, within multi-planetary systems including hot-Super Earth, we compared those with and without exo-Jupiter using their host star and exoplanet parameters, such as metallicity [Fe/H], $T_{eff}$ and $R_*/R_p$.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.197-201
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• 2001

Output and cost efficiency in the production of hot-rolled strip depend to a large content on the uniformity of geometric and mechanical properties over the length and width of the rolled end product. To ensure the homogeneous temperatures required for this during the rolling process a system to measure and evaluate the transverse temperature profile was developed and implemented in production. The systems used consist of temperature scanners and computers for measurement and data evaluation. The systems have been installed in Kwangyang hot strip mills, in the cases at the exit of the finishing train and at the entry of the coiler. They are used in production to determine the effect of the finishing train and the cooling zone on the technological properties of the hot rolled strip.

• Journal of Powder Materials
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• v.12 no.4 s.51
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• pp.255-260
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• 2005

Direct solid state synthesis by hot pressing has been applied in order to produce high efficiency $Zn_4Sb_3$ bulk specimens. Single phase $Zn_4Sb_3$ with 98.5% of theoretical density was successfully produced by direct hot pressing of elemental powders containing 1.2 at.% excess Zn. Thermoelectric properties as a function of temperature were investigated from room temperature to 600 K and compared with results of other studies. Transport properties at room temperature were also evaluated. Thermoelectric properties of single phase $Zn_4Sb_3$ materials produced by direct synthesis were measured and are comparable to the published data. Direct solid state synthesis by hot pressing provides a promising processing route in this material.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.663-666
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• 2002

Hard disk drived (HDD) in computer are used extensively as data storage capacity. The trend in the computer industry to produce smaller disk drives rotating at higher speeds requires an improved understanding of fluid motion in the space between disks. The distribution of pressure disturbance on disks has relation to flow structure. To investigate the flow structure, time-resolved hot-wire measurements of the circumferential velocity component were obtained for the flow between the center pair of four disks of common radius $R_2$ coretating at angular velocity ${\Omega}$ in a fixed cylindrical enclosure. Hot-wire supporter acts as an obstruction in this case. The effects of rotating speed and size of hot-wire supporter diameter between disks on the flow driven by disks were investigated. Velocity spectra at the fixed space were measured to obtain the structure of inner and outer region in flow field.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.2
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• pp.10-17
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• 2001

Drilling is one of the most important operations performed in the machining industry. And the material of the workpiece has a profound effect on the tool life, the surface finish produced and the overall economy of the process. Hot-rolled high strength steels have been used for automobile structural material, owing to high hardness and machinability of the material. However, in the drilling of hot-rolled high strength steels, the current knowledge of tool wear and machinability are insuf-ficient. There, it is desirable to monitor drill wear status and hole quality changes during the hole drilling process. Accordingly, this paper deals with the cutting characteristics of the hot-rolled high strength steels using common HSS drill. The performance variables include the drilling thrust, torque and drill wear data obtained from drilling experiments con-ducted on the workpiece. Also drill were is measured by acoustic emission system and computer vision system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.5
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• pp.510-517
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• 2004

A fine hot-wire is used both as a heating element and a temperature sensor in transient hot-wire method. The traditional sensor system is unnecessarily big so that it takes large fluid volume to measure the thermal conductivity. To dramatically reduce this fluid volume, a new sensor fabrication and a data processing method are proposed in this article. Contrast to the conventional and most popular two wire sensor, the new sensor system is made up of divided multiple long and short wires. Through validation experiments, it is found that the measured thermal conductivities of the glycerin are exactly same each other between the conventional and proposed new method. Also some technical considerations in arranging the multiple wires are briefly discussed.