• Journal of Electrical Engineering and information Science
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• v.1 no.1
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• pp.45-50
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• 1996

This paper mainly describes the wind load assumption of 765kV transmission towers. We analyzed wind velocity data a meteorological observatories to get the wind velocity of 50 years return period by using Gumbel I type extreme value distribution. By multi-correlative regression analysis method, wind velocity at no observation site was obtained. Reference dynamics wind pressure map was obtained from above analysis and the wind pressure was classified as three regio in high temperature season.

• Journal of the Mineralogical Society of Korea
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• v.31 no.3
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• pp.161-172
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• 2018

Multi-anvil press (MAP) is one of the high pressure apparatuses and often generates the pressure-conditions ranging from 5 to 25 GPa and temperature-conditions up to $2,300^{\circ}C$. The MAP is, therefore, suitable to explore the pressure-induced structural changes in diverse earth materials from Earth's mantle and the bottom of the mantle transition zone (~660 km). In this study, we present the experimental results for pressure-load calibration of the 1,100-ton multi-anvil press equipped in the authors' laboratory. The pressure-load calibration experiments were performed for the 14/8 step, 14/8 G2, 14/8 HT, and 18/12 assembly sets. The high pressure experiments using ${\alpha}$-quartz, wollastonitestructure of $CaGeO_3$, and forsterite as starting materials were analyzed by powder X-ray diffraction spectroscopy. The phase transition of each mineral indicates the specific pressure that is loaded to a sample at $1,200^{\circ}C$: a transition of ${\alpha}$-quartz to coesite at 3.1 GPa, that of garnet-structure of $CaGeO_3$ to perovskite-structure at 5.9 GPa, that of coesite to stishovite at 9.2 GPa, and that of forsterite to wadsleyite at 13.6 GPa. While the estimated pressure-load calibration curve is generally consistent with those obtained in other laboratories, the deviation up to 50 tons is observed at high pressure above 10 GPa. This is partly because of the loss of oil pressure at high pressure resulting from the differences in a sample chamber, and the frictional force between pressure medium and second anvil. We also report the ${\sim}200^{\circ}C/mm$ of thermal gradient in the vertical direction of the sample chamber of 14/8 HT assembly. The pressure-load calibration curve and the observed thermal gradient within the sample chamber can be applied to explain the structural changes and the relevant macroscopic properties of diverse crystalline and amorphous earth materials in the mantle.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.289-292
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• 2009

Injector dynamics of multi swirl injectors in an annular combustor have been investigated by LES(Large Eddy Simulation) turbulent model with MPI parallel computation technique. The present study employs the LM6000 lean premixed swirl-stabilized annular combustor. Real shape combustor is simulated in order to investigate the detail interaction mechanism among multi-injectors. The strong vortex breakdown occurs at the impinging surface between the adjacent injectors so that the complex and strong oscillatory pressure propagates inside of the combustor. Tangential pressure fluctuation mode was captured by including multi injectors in computational domain.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.546-552
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• 2012

This paper is a study on squeal noise simulation under the consideration of temperature and pressure dependent material properties of friction material. For this, data of pressure and temperature dependent material properties of lining is achieved by using lining data base and exponential curve fit. Complex eigenvalue analysis is performed for predicting squeal noise frequency and instability and chassis dynamo test is performed for achieving squeal noise frequency, sound pressure level, occurrence temperature & pressure. Initial multi models are composed for considering complex interface conditions such as pad ear-clip, piston-housing and guide pin-torque member. The simulation result of base models is compared with the test result. Squeal noise simulation under the consideration of temperature and pressure dependent material properties of friction material is performed and analyzed using multi models. And additional condition is disc material property variation. Entire simulation conditions are combined and analyzed. Finally, this paper proposes direction of the warm squeal noise model.

• Journal of the Semiconductor & Display Technology
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• v.13 no.1
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• pp.43-49
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• 2014

Zinc-tin oxides (ZTO) thin film transistors have been fabricated at different process pressure via re sputtering technique. TFT properties were improved by depositing channel layers at lower pressure. From the analysis of TFTs comprised of multi layer channel, deposited consecutively at different sputtering pressure, it was suggested that the electrical characteristics of TFTs were mainly affected by interfacial layer due to their high conductance, however, the stability under the NBIS condition was influenced by whole bulk layer due to low concentration of positive charges, which might be generated by the oxygen vacancy transition, from Vo0 to $Vo^{2+}$. Those improvements were attributed to increasing sputtered target atoms and decreasing harmful effects of oxygen molecules by adopting low sputtering pressure condition.

• The KIPS Transactions:PartA
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• v.19A no.1
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• pp.45-50
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• 2012

The demand for faster execution time and lower energy consumption has compelled architects of embedded processors to customize it to the needs of their target applications. These processors consequently provide a rich set of specialized instructions in order to enable programmers to access these features. Such an instruction is typically a $multi$-$output$ $instruction$ (MOI), which outputs multiple results parallely in order to exploit inherent underlying hardware parallelism. Earlier study has exhibited that MOIs help to enhance performance in aspect of instruction counts and code size. However the earlier algorithm does not consider the register pressure. So, some selected MOIs introduce register spill/reload code that increases the code size and instruction count. To attack this problem, we introduce a novel iterated instruction selection algorithm based on the register pressure of each selected MOIs. The experimental results show the suggested algorithm achieves 3% code-size reduction and 2.7% speed-up on average.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.478-481
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• 1995

This paper presents the system demonstrator for an optical fiber sensor system developed as a technological evaluator suitable for generic sensric sensing applications. The new type of fiber-optic sensor employed a diaphragm displacement transforms pressure into optical intensity. Form this sensing technique, we can know the variation of source intensity, the loss of a optical fiber, and the reflectivity of the diaphragm surface. Experimental results are applied to the low-pressure transducer suitable for measuring miniature pressure.

• Journal of the Korea Society of Computer and Information
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• v.25 no.3
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• pp.155-162
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• 2020

Among the fourth industrial revolution technologies, products related to healthcare using IoT and sensors are currently being developed. We design and develop an interaction system based on user standing posture recognition using multi-channel large area pressure sensors in this paper. To this end, first of all we investigate major sensor markets of the sensor industry and review technology trends and the current and future of smart healthcare. Based on this survey, we examine and compare cases developed at home and abroad for multi-channel large-area pressure sensors, which are key components of the system that we want to develop. We recognize the standing posture status of the user through the developed system and experiment with how effective it is actually in user posture calibration and apply the research results to various healthcare devices' medical fields based on this.

• The Journal of Engineering Geology
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• v.29 no.3
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• pp.201-209
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• 2019

Bottom-up multi-stage pressure grouting is widely applied to domestic slopes and tunnels. It involves injecting earth from the ground to the surface after drilling. Various reports of construction performance have demonstrated its wide applicability. However, little research has studied top-down multi-step pressure grouting in Korea, which involves injection from the surface. This paper compares the grouting effect of both the established bottom-up method and the top-down method in soil box and field tests. The soil box test showed that the bulb volume of the top-down method is ~24% less than that of the bottom-up method. The field test confirmed that the top-down method has a wider grouting range and a higher injection density per area than the bottom-up method.

• Journal of the Korean Institute of Gas
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• v.27 no.2
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• pp.57-64
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• 2023

As the meter reading method of gas meters develops, smart gas meters capable of remote meter reading (leak checking meters and multi-function safety meters) are being used. These meters have a function to judge leakage by utilizing the flow rate and pressure data collected as an additional function. Leakage judgment function using flow rate data has valid cases in the actual field, but the pressure data-based leakage judgment standard is based on not only the pressure value change due to leakage but also various factors (pressure regulator pressure, connection with adjacent meters, usage of adjacent houses, location of meters, etc.). There is a problem with pressure magnitude changes (levels). In this paper, as a technique that can judge leaks by using pressure data collected from smart gas meters, it was developed through preprocessing of pressure data, criteria for pressure value ranges related to leaks, leak judgment techniques, and application case verification.