• Journal of KSNVE
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• v.10 no.6
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• pp.971-976
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• 2000

High level random vibration environments induced while launching of spacecraft can damage sensitive electronic equipment, unless the equipment is properly packaged. Thus careful consideration on the launch environment, especially for high level random vibration, is required in the design stage of electronic equipment of spacecraft. This paper describes the development process of Solar Array Regulator for KOMPAT-2, which is designed and tested by Korean engineers. Both analytical and experimental techniques are introduced in this paper.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.460-471
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• 2019

The aim of this study was to examine the scale and market share of Chinese's research facility & equipment in the domestic research equipment market of basic and analytical science field for analyzing the difference of the number and amount of construction by year of acquisition, national research facility equipment standard classification code, and type of institution based on the information of the research equipment invested by the Korean government for the past 14 years. In addition, we analyzed the correlation among the year of acquisition, equipment standard classification code, and type of institution variables. As of January 1 2019, from 2005 to 2018, 50 Chinese's research facilities & equipments (main equipment with a construction cost of 30 million won or more) built in the basic and analytical science fields were selected for this study and their number of construction, amount of construction, year of acquisition, type of institution, and standard classification code were analyzed. Differences of the number and amount of construction with-in and by year of acquisition, standard classification code, and type of institution were tested using a single sample Chi-square test, Mann-Whitney U test, and Kruskal-wallis test. The correlation among the three variables was analyzed by using the Chi-square test of cross-tabulation analysis. And there was a statistically significant correlation among the year of acquisition, standard classification code, and type of institution (p<.05). Compared to the 2000s, in the 2010s, high-priced Optical Electronics/Video Equipment was installed at private universities, private enterprises, and government-affiliated research institute. Therefore, the domestic construction status of Chinese's research facility & equipment in the basic science and analytical science field is less than that of the domestic ones, but the number and the amount of construction are increasing statistically. So it is necessary for the government to be able to recognize the possibility that the Chinese's research facility and equipment can encroach on the domestic research industry market and to prepare related provision.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.6
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• pp.808-812
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• 2010

This paper studies the finite element modeling and analytical parameters for the numerical evaluation of dynamic stiffness of large foundation for shipboard equipments such as marine diesel engine. For the purpose, numerical method and procedure to evaluate the dynamic stiffness are established based on the impact test method, which are applied for the dynamic stiffness evaluation of a real diesel generator foundation of ship. Numerical investigations compared with the measured data are carried out to evaluate the effects of modeling ranges of ship substructure, finite element sizes, lower support structures and damping coefficients. From the results, modeling and analytical parameters for proper evaluation of dynamic stiffness of large foundation of shipboard equipment are suggested.

• The monthly packaging world
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• s.327
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• pp.84-93
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• 2020

• Journal of Information Processing Systems
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• v.16 no.6
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• pp.1271-1280
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• 2020

The yield and quality of a micromanufacturing process are important management factors. In real-world situations, it is difficult to achieve a high yield from a manufacturing process because the products are produced through multiple nanoscale manufacturing processes. Therefore, it is necessary to identify the processes and equipment that lead to low yields. This paper proposes an analytical method to identify the processes and equipment that cause a defect in the plastic ball grid array (PBGA) during the manufacturing process using logistic regression and stepwise variable selection. The proposed method was tested with the lot trace records of a real work site. The records included the sequence of equipment that the lot had passed through and the number of faults of each type in the lot. We demonstrated that the test results reflect the real situation in a PBGA manufacturing process, and the major equipment parameters were then controlled to confirm the improvement in yield; the yield improved by approximately 20%.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.4 s.121
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• pp.317-323
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• 2007

Non-contact underwater explosions against surface ships could cause extensive equipment damage and render the ship inoperative. As an analytical method, DDAM(dynamic design and analysis method) is used for ship shock design. In this paper, in order to verify the finite element model of large shipboard equipment, modal test of equipment was performed. Major objective of this paper is to describe shock analysis methodology for large shipboard equipment attacked to the top and bottom foundations.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.3
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• pp.868-876
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• 1995

This study deals with a position control of an electro-hydraulic servo system which consist of cylinder and high speed on-off valves operated by microcomputer. The merits of PWM control of hydraulic equipment are the robustness of the high spee on-off valve, its low price and the direct control without D/A converter. In the PWM control of high speed on-off valve, the time lag and switching time existing between the input and output signals of valve are considered as demerit points. To get analytical results, the effects of these demerits have to be clarified in detail. The object of this study is to propose a mathematical model for the behavior of high speed on-off valve and to get analytical results of this system. The dynamic characteristics of this system is examined by digital computer simulation analytically and compared with experimental results to varify the proposed mathematical model.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.69
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• pp.1-12
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• 2001

In this paper, the consumable concurred spare parts requirement determination problem of newly procured equipment systems is considered. The problem is formulated as the operational availability maximization problem with any given fund limitation. the that the failure of a part follows a Poisson process and part failure rate is constant in spite of the decrease of number of equipments during operational period, an analytical method is developed to obtain spare part requirements using the generalized Lagrange multipliers method, The numerical examples show that analytic solution is mostly equal to the realistic solution obtained from simulation regardless of assumptions about part failure rate. It is expected that the analytical method developed in the paper can be effectively used to make a budget for provisioning the concurrent spare parts of newly procured equipment system.

• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.1
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• pp.1-9
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• 2009

This study presents an analytical model of an automotive steering hose containing tuner(flexible spiral metal tube) to reduce the ripple pressure induced by steering vane pump. The double-wall side branch composed in a steering hose containing tuner was analogically considered as a filter in a conduit. Specialized test equipment was manufactured for the estimation of speed of sound in a conduit and measurement of amplitude ratio between the propagated ripple pressures of inlet and outlet of the steering hose. Experimental data of entire frequency ranges can be obtained through the test once in short time. The results of three points' measurement method and cross-correlation method to estimate the speeds of sound in a hose, tuner, and side branch respectively reveal that cross-correlation method can be used practically. The results of simulation and experiment were so close, especially in the range of engine idling speed, that the proposed analytical model in this study was validated. Sensitivity analyses and experiments show that longer tuner is preferable, and that the positive-positive composition of the steering hoses containing tuner is superior to others to attenuate ripple pressure.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.100-105
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• 2021

This paper proposes the polydimethylsiloxane (PDMS) blade coating method for fabrication of paper-based analytical device (PAD) that is able to monitor the disease diagnosis and progress without special analytical equipment. The mold that has PAD design is easily modified by using laser cutting technique. And the fabricated mold is used for hydrophobic barrier formation by blade coating. We have optimized the stable formation of PDMS hydrophobic barrier as blade coating condition, which is established by analyzing the structure of the PDMS hydrophobic barrier and change of hydrophilic channel size as thickness of the ink and contact time with the chromatography paper. Based on optimal condition, we demonstrate that PAD as biosensor can apply to detect protein, glucose, and metal ion without special analysis equipment.