• 한국시뮬레이션학회논문지
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• 제12권3호
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• pp.41-53
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• 2003

The major components of an engine are engine block (or cylinder block), cylinder head, crank shaft, connecting rod and cam shaft. Thus the engine shop usually consists of six sub-lines, five machining lines and one assembly line. Flow line is the typical concept of layout for machining these parts, especially for engine block. In order to design an engine block machining line, several factors should be considered such as yearly production target, working hours, machines, tools, material handling equipments and so on. If the designers of manufacturing line were unaware of some factors those would be influenced on the system performance, it would make greater problems in the phase of mass production. Therefore the initial design of engine block machining line should be verified carefully. Simulation is the most powerful tool for analyzing the initial layout. This paper introduces the major factors those should be considered for designing the machining line and their effects on the system performance. 3D simulation models are developed with QUEST. Using the simulation model developed the initial layout is analyzed, and we suggest some ideas for improvement.

• 천문학회지
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• 제29권spc1호
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• pp.119-122
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• 1996

The case for a massive black hole in the center of the Galaxy is reassessed using improved modeling techniques and observational data. A dark mass of ${\~}{\times} 10^6$ Mo is present within 0.2 pc of the Galactic center. However, the available data can be modeled, without appealing to a massive black hole, using an extended distribution of dark stellar remnants (neutron stars and stellar mass black holes) provided that the stellar initial mass function in the central parsec is deficient in stars less massive than $\~$1 Mo. Such a situation may be a natural consequence of repeated gas build-up followed by starbursts in the central region. A clear distinction between this and the massive central black hole model cannot be made using red giant tracers outside 0.2 pc due to uncertainties in the radial velocity dispersion distribution. The cluster of massive early-type emission-line stars in the central parcsec more effectively probe the mass distribution close to Sgr A $\ast$, but their small number and partial rotational support complicate mass determinations. Proper motion determinations for stars within 0.5' of Sgr A$\ast$ may be the most effective means of unambiguously determining the mass distribution in the immediate vicinity of the Galactic center.

• Mass Spectrometry Letters
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• 제7권1호
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• pp.1-11
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• 2016

Various efforts have been developed to improve sample preparation steps, which strongly depend on hands-on processes for accurate and sensitive quantitative proteome analysis. In this study, we carried out heating the sample prior to trypsin digestion using an instrument to improve the tryptic digestion process. The heat shock generated by the system efficiently denatured proteins in the sample and increased the reproducibility in quantitative proteomics based on peptide abundance measurements. To demonstrate the effectiveness of the protocol, three cell lines (A human lung cancer cell line (A549), a human embryonic kidney cell line (HEK293T), and a human colorectal cancer cell line (HCT-116)) were selected and the effect of heat shock was compared to that of normal tryptic digestion processes. The tryptic digests were desalted and analysed by LC-MS/MS, the results showed 57 and 36% increase in the number of identified unique peptides and proteins, respectively, than conventional digestion. Heat shock treated samples showed higher numbers of shorter peptides and peptides with low inter-sample variation among triplicate runs. Quantitative LC-MS/MS analysis of heat shock treated sample yielded peptides with smaller relative error percentage for the triplicate run when the peak areas were compared. Exposure of heat-shock to proteomic samples prior to proteolysis in conventional digestion process can increase the digestion efficiency of trypsin resulting in production of increased number of peptides eventually leading to higher proteome coverage.

• 한국의류산업학회지
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• 제12권2호
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• pp.162-171
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• 2010

This study aims to discuss what changes Korean clothing companies and manufacturers have undergone with production facilities moving abroad due to offshore outsourcing and examine what conditions the clothing manufacturers are facing and how the clothing companies recognize those manufacturers. For these purposes, in-depth interviews were conducted with 24 firms with annual production capacity of more than 200,000 pieces among clothing brands for the domestic market, clothing exporters and promotion agencies. Those interviewed firms were the companies who were found to produce more than 200,000 pieces of clothing per year, and the interview-based survey was conducted from December 18, 2008 to January 30, 2009. The key findings from this study are as follows; first, a high percentage of interviewed firms were producing only a small number of items in Korea with a large part of their production line transferred abroad or outsourcing all of their production abroad only with their headquarters in Korea. Second, many were employing contractors rather than their own factories. Third, when asked about the wage levels of clothing manufacturers, many of the clothing companies gave responses such as: 'They are just our contractor, so we respect their decision,' 'We don't know because it's none of our business,' or 'We don't know at all.' Fourth, when asked about the work environment of clothing manufacturers, the clothing companies gave responses such as: 'We know in part,' 'To our knowledge, they conform to the Labor Standards Law,' or 'We don't know at all.' Fifth, the production line of clothing manufacturers featured straight-line systems, specialization, pairing and compounding/mixing. Sixth, it was found that clothing companies had interest in mass customization but their preparations were not satisfactory.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.656-659
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• 2003

Although Hereafter a mass production will claim for patterning nano sized thickness or line in micro-nano industry. existent lithography fabrication has many usable fields, it has complex fabrication steps, expensive values and row work rates. Development of Dip-pen type nano plotter using polymer actuator can construct row cost mass production system because it will change existent lithography fabrication more simple and easy.

• 대한두경부종양학회지
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• 제20권1호
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• pp.52-54
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• 2004

Ectopic cervical thymic tissue is rarely reported in medical literature, but it should be included in the differential diagnosis of neck masses, especially in children. It occurs in the line of descent of the thymus from the angle of the mandible to the superior mediastinum. A preoperative diagnosis is seldom considered and is often misdiagnosed as a possible tumor or a lymph node. We present a case of a 2-month-old infant with an asymptomatic enlarging right neck mass. Patient underwent complete excision of the mass.

• 천문학회보
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• 제45권1호
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• pp.61.1-61.1
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• 2020

We examine the HI gas kinematics and distribution of galaxy pairs in group or cluster environment from high-resolution Australian Square Kilometre Array Pathfinder (ASKAP) WALLABY pilot observations. We use 22 well-resolved galaxies in the Hydra cluster of which 4 galaxies are visually identified as pairs and others are isolated ones. We perform profile decomposition of HI velocity profiles of the galaxies using a new tool, BAYGAUD which enables us to separate a line-of-sight velocity profile into an optimal number of Gaussian components based on Bayesian MCMC techniques. All the HI velocity profiles of the galaxies are decomposed into kinematically cold or warm gas components with their velocity dispersion, 4~8 km/s or > 8 km/s, respectively. We derive the mass fraction of the kinematically cold gas with respect to the total HI gas mass, f = log10(M_cold / M_HI), of the galaxies and correlate them with their dynamical mass. The cold gas reservoir of the paired galaxies in the Hydra cluster is found to be relatively higher than that of the isolated ones which show a negative correlation with the dynamical mass in general.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.859-863
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• 1995

Presented in the paper are a review of sorting and buffering system(SBS), the design procedure of a SBS and an analytical model for the initial alternative generation. SBS is an automated material handling system in which incoming items of different part types are automatically sorted and buffered so that the processing machines can process the part in lots. SBSs play a key role in modern manufacturing systems ans are widely found in mass fabrication lines, packaging and palletizing, and disribution centers.

• Tribology and Lubricants
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• 제16권4호
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• pp.289-294
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• 2000

This paper present the contact stresses, which considers the shear stress at the cam and follower interface in the direct acting type valve train system of a high speed engine. To determine the contact condition, the normal contact forces are calculated by using the lumped mass dynamic modeling. The line contact is considered between the cam and follower interface. The variations of dynamic stresses are presented as a function of camshaft rotational angle. Also the effects of various design parameters are investigated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.74-76
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• 1995

This paper describes the precise position control of the linear DC motor for carrier. We analyze the switching line of seek mode control and propose the modified switching line according to the mass and distance. Experimental results demonstrate that good performance is achieved by the proposed controller.