• The Journal of Information Systems
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• v.17 no.4
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• pp.301-319
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• 2008

The display market has been replaced by the FPD (Flat Panel Display) from the CRT (Cathode-Ray Tube) since the late 1990s. In the FPD production line, the most equipment has high price. Thus, when the equipment has multi-function, the repetitive process is arranged for the equipment. However, such disposition of equipment results in more complicated process flow owing to repetitive operations. This reduces the production capacity and increases lead-time in turn. In this paper, we develop an AutoMod simulation system that derives to information about the quantity, production lead-time, utilities of facilities, and occupation rates of racks. In this simulation system, we consider the situation where the equipment might be broken and suspended randomly. For the developed system, we first evaluate a production plan with current layout and then, propose a revised alternative plan. Using the same simulation scheme, we investigate comparing the production quantity and lead-time with the two plans. In addition, for a proposed alternative, we try to forecast the most adequate rule between the two job dispatching rules which are FOR (Fewest Operation Remaining) and FCFS (First Come First Serve) through simulation.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.12
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• pp.597-600
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• 2002

Film Bulk Acoustic wave Resonator (FBAR) using thin piezoelectric films can be made as monolithic integrated devices with compatibility to semiconductor process, leading to small size and low cost, high Q RF circuit elements with wide applications in communications area. This paper presents a MMIC compatible suspended FBAR using surface micromachining. Membrane is composed $Si_3N_4SiO_2Si _3N_4$ multi layer and air gap is about 50${\mu}{\textrm}{m}$. Firstly, We perform one dimensional simulation applying transmission line theorem to verify resonance characteristic of the FBAR. Process of the FBAR is used MEMS technology. Fabricated FBAR resonate at 2.4GHz, $K^2_{eff}$ and Q are 4.1% and 1100.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.7
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• pp.997-1008
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• 2010

The mooring line tension and motion response of a floating fish reef system were analyzed using a Morison equation type numerical model. The reef structure was constructed with pipe and suspended up from the bottom with a single, high tension mooring. Input forcing parameters into the model consisted of both regular and random waves, with and without currents. Heave, surge and pitch dynamic calculations were made, along with the tension response in the mooring lines. Results were analyzed in both the time and frequency domains and where appropriate, linear transfer functions were calculated. In addition, damped and natural periods of the system were determined to examine a resonating situation.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.67-68
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• 2006

A suspended microstrip line structure over mushroom-like SMPs is designed and is applied to a dual-frequency and dual-polarization microstrip patch antenna. This structure has a distinctive and sharp rejection band and provides near 0 dB insertion loss outside the rejection band. Applying the structure to the conventional DFDP antenna enhanced the isolation between the two ports more than 20 dB. The structure is expected to have a wide range of applications in antennas and filters due to its compactness and integrability in circuits.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.7
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• pp.687-692
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• 2002

The design of broadband patch antenna with the new feeder structure is proposed in this paper. The antenna operates in the center frequency 5.8 GHz. Proposed the new feeder structure has also broadband characteristic and reduced antenna size. To confirm broadband characteristic, compared with probe feeder antenna. After designing and manufacturing, the antenna bandwidth enhanced by 34.5 % and the patch size reduced by 45 %.

• 한국해양학회지
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• v.20 no.3
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• pp.55-61
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• 1985

Two hundred suspended-matter samples were collected from the continental shelf off the southeast coast of Korea during September, 1981, March, 1982 and April 1983. Superficial bottom sediments on the shelf were also taken. Based on the alalyses of TSM distribution and concentration patterns, it is considered that finegrained suspended matters are restricted to nearshore-inner shelf showing a band or zone paralleling with coastal morphology. This fact suggests a limitation of "modern" fine grained sediments to a nearshore and inner shelf band. The sand deposits with the lower value of mud content (<5%) adjacent to the shelf break and on the outer shelf would probably be "relict" sediments (old beach sediments) deposited in response to a lower stand of sea level during the Pleistocene ice age. The transgression did little to alter the distribution of sand on the outer shelf in this particular study area. The progress of shore line was so rapid that a given locality was in the beach zone and subject to rapid longshore drift and extensive reworking only for a few years. Probably the most pronounced effect of the transgression was sorting of the sand, and at least partial winnowing out of the finer fractions.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.6
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• pp.593-604
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• 2017

The suspended particulate matter(PM) was measured in subway tunnel of Seoul Line 1 to 9 in order to evaluate the pollution degree and characteristics of the PM in the subway tunnel. Also, to analyze the effect of outdoor aerosol concentration on the PM concentration of subway tunnels, the ambient PM concentration around the subway station was extracted by spatial analysis using $PM_{10}$ data of Seoul air pollution monitoring network. Finally, in order to understand pollution pattern in the Seoul subway tunnels, cluster analysis was performed based on input data set such as PM levels in tunnel, tunnel depth, length, curvature radius, outdoor ambient air pollution levels and so on. The average concentration of $PM_{10}$, $PM_{2.5}$, and $PM_1$ on subway tunnels were $98.0{\pm}37.4$, $78.4{\pm}28.7$, and $56.9{\pm}19.2{\mu}g/m^3$, respectively. As a result of the cluster analysis, tunnels from Seoul subway Line-1 to Line-9 were classified into five classes, and the concentrations and physical properties of the tunnels were compared. This study can provide a method to reduce PM concentration in tunnel for each pollution pattern and provide basic information about air quality control in Seoul subway tunnel.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.318-323
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• 1995

To improve wastewater treatment in a confectionery factory and to optimize chemical coagulation process, this study was performed. $COD_{Mn}$ and total solid of untreated wastewater were $200{\sim}820ppm\;and\;860{\sim}1350ppm$, respectively. Composition of total solid was sugar 40%, protein 10%, hexane-soluble 20%, and ash 30%. Turbidity at 650 nm and the amount of suspended solid (SS) showed correlation, thus turbidity could be used for the on-line measurement of SS. The most effective combination of coagulants for the removal of $COD_{Mn}$ and SS was that of $Al_2(SO_4)_3\;and\;Ca(OH)_2$. The optimal concentration of $Al_2(SO_4)_3\;and\;Ca(OH)_2$ was 480 ppm and 200 ppm, respectively. Optimal retention time of wastewater for $Al_2(SO_4)_3$ addition $Ca(OH)_2$ addition : flocculation was 2 : 2 : 10 min. Multiple treatment of $Al_2(SO_4)_3:Ca(OH)_2$ overcame coagulation inhibition by gelatin and detergent, and addition of microbial sludge reduced it.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.436-440
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• 2008

Monorail is a type of LRT that a train, made with $2{\sim}4$ cars runs on single track. Monorail can be divided into two types - straddled type, running on track beam and suspended type, running suspended from track beam. After Wuppertal, world's first monorail in German, many monorails are currently operated in Australia, U.S.A, Japan etc. In macountry, it was decided to introduce monorail to 3rd line of Daegue. Daegue's 3rd line is public financial project and supported about 60% of total project cost by central government. The central government announced a standard for rubber-wheel type LRT and steel-wheel type LRT. It becomes a guide to local government willing to introduce this type of LRT. The standard for monorail hasn't announced yet although the necessity of research has grown. Korea Railroad Research Institute which has been asked to research by Ministry of Land Transport and Maritime Affairs has carried out research on standard of monorail considering domestic condition. The on-going research is described in this paper. We wish that it becomes national standard and a good guide for local government.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.1
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• pp.56-59
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• 2020

Porcelain insulators are typically exposed to surface discharge and lightning impulse in service. This study investigates the insulation characteristics of the external and internal discharges of a porcelain insulator with respect to its flashover for a 154 kV transmission line. The experiments are also conducted using a wet flashover test and an impulse test based on the external discharge and the internal penetration, to classify the flashover voltage-time curve of the porcelain insulator. When an impulse with a strength of 2,500 kV/㎲ was applied three times to 6.5 mm ceramic samples, electrical penetration of approximately 70% occurred. The impulse experiment confirmed that the electrical penetration inside the porcelain insulator coincided with the area where the electric field was concentrated. The wet flashover voltage test revealed that the flashover threshold voltage increases by approximately 7% after cleaning of the surface.