• Structural Engineering and Mechanics
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• v.66 no.4
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• pp.515-529
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• 2018

Multiple hazards (multihazard) conditions may cause significant risk to structures that are originally designed for individual hazard scenarios. Such a multihazard condition arises when an earthquake strikes to a bridge pre-exposed to scour at foundations due to flood events. This study estimates the impact spectrum of flood-induced scour on seismic vulnerability of bridges. Characteristic river-crossing highway bridges are formed based on the information obtained from bridge inventories. These bridges are analyzed under earthquake-only and the abovementioned multihazard conditions, and bridge fragility curves are developed at component and system levels. Research outcome shows that bridges having pile shafts as foundation elements are protected from any additional seismic vulnerability due to the presence of scour. However, occurrence of floods can increase seismic fragility of bridges at lower damage states due to the adverse impact of scour on bridge components at superstructure level. These findings facilitate bridge design under the stated multihazard condition.

• Proceedings of the Korea Multimedia Society Conference
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• 2012.05a
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• pp.26-27
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• 2012

Reflection considered as the view disturbing noise in optical systems, such as stereo camera in autonomous vehicles especially in night. Reflection caused by the street light or due to rainwater under adverse weather conditions. A blur image detected by the camera that results in wrong guidance to vehicle for detecting its track. A vehicle guidance approach through stereo vision can be same in day and night time. However it cannot be guided with same image analysis due to diverse illumination conditions. We develop the technique that shows its efficacy with illustrations of reflection removal off the camera lens and vehicle tracking control.

• Journal of Welding and Joining
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• v.21 no.2
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• pp.70-75
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• 2003

Spot welding is a process that sheet metals are joined in one or more spot by heating at the faying interface. In this process, the spatter is dispersed from melted area. It has been reported that spatter generation has adverse effects on weld quality. However, no systematic study has been carried out to find out its effect on weld quality in resistance spot welding processes. In this study, specially designed specimen are used to perform experimental investigation of spatter generation and its effect. Major finding of this study show trends in tensile-shear strength for various amounts of spatter generated during spot welding process. Thus, optimum welding conditions are proposed in view of spatter generation and tensile-shear strength. (Received December 11, 2002)

• International Journal of Aeronautical and Space Sciences
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• v.15 no.3
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• pp.232-240
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• 2014

Transonic flow past a NASA SC(2)-0710 airfoil with deployments of a spoiler up to $6^{\circ}$ was studied numerically. We consider angles of attack from $-0.6^{\circ}$ to $0.6^{\circ}$ and free-stream Mach numbers from 0.81 to 0.86. Solutions of the unsteady Reynolds-averaged Navier-Stokes equations were obtained with a finite-volume solver using several turbulence models. Both stationary and time-dependent deployments of the spoiler were examined. The study revealed the existence of narrow bands of the Mach number, angle of attack, and spoiler deflection angle, in which the flow was extremely sensitive to small perturbations. Simulations of 3D flow past a swept wing confirmed the flow sensitivity to small perturbations of boundary conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.353-357
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• 2000

A dimensioning system in a manufacturing process is often complex, especially when a lot of operations are involved in the process. Determination of operational dimensions and tolerances becomes even more complicated if there exist inconsistencies between operational and design relationships among operational dimensions in machining. This chart furnishes a record of the relationships in an easy-to-grasp form, proves that sufficient stock for a cut is available even under adverse conditions, and also proves that separate operations, when taken together, will harmonize as desired. In this paper, various existing roles of the chart have been extended to an operational routing sheet by generating it automatically, providing machining conditions, and verifying operational tolerances.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.4
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• pp.387-392
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• 1995

Though a variety of non-conventional feedstuffs have been successfully evaluated in research stations in Asian countries, there had been little adoption of these technologies at the small farm level. The methodology and results of three separate on-farm trials evaluation the possible use of some non-conventional feedstuffs in broiler diets under small farm conditions in Sri Lanka are reported in this paper. In all trials, the commercial mash, that in normally used in the farms, served as the control. In trials 1 and 2, 5 and 10% cassava leaf meal, respectively, was substituted (w/w) for the commercial mash and fed to broilers for six weeks. In trial 3, several non-conventional feedstuffs (cassava leaf meal, rubber seed meal, ipil ipil leaf meal and died poultry manure) were substituted (w/w) for the commercial mash at levels of 15-20%. The results demonstrated that these non-conventional feed resources can be used in broiler diets under small farm conditions, with no adverse effects on performance. The salient features of on-farm animal research are highlighted.

• Journal of the Semiconductor & Display Technology
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• v.8 no.4
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• pp.59-63
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• 2009

This paper presents two dimensional simulation results of an inductively coupled $Ar/O_2$ plasma reactor. The effects of operating conditions on the plasma properties and the uniformity of atomic oxygen near the wafer were systematically investigated. The plasma density had the linear dependence on the chamber pressure, the flow rate of the feed gas and the power deposited into the plasma. On the other hand, the electron temperature decreased almost linearly with the chamber pressure and the flow rate of the feed gas. The power deposited into the plasma nearly unaffected the electron temperature. The simulation results showed that the uniformity of atomic oxygen near the wafer could be improved by lowering the chamber pressure and/or the flow rate of the feed gas. However, the power deposited into the plasma had an adverse effect on the uniformity.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.42-51
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• 2003

The global demand for underground facilities has increased substantially in the past decades, and a substantial number of underground projects have had to deal with challenging ground conditions in urban environments. Particularly challenging are weak and unstable water bearing soils. Advancements in shielded TBM tech-nology have led to significant improvements regarding the ability to control ground deformations in soft ground. Nonetheless, ground collapse may occur even when the most advanced TBM designs are employed if unexpected adverse ground conditions are encountered or if insufficient stabilizing pressure is transferred to the tunnel face. This paper reviews common approaches for face stability and face pressure transmission calculations, and provides an overview of some of the latest technological developments and considerations for soft ground TBM applica-tions.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.951-955
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• 1999

The effects of restricting feed [60% of ad libitum (AL) intake] (FR) or water provided from 0900 h to 1600 h, daily) (WR) or both (FWR) from 14 to 42 days of age on heterophil/lymphocyte (H/L) response and performance in broiler chickens under the hot humid tropical conditions were determined. Feed and/or water limitation retarded growth, but had no adverse effect on overall feed conversion ratio and survivability. The trend for total feed and water consumption was similar to body weight pattern with AL>WR>FR>FWR. The nutritional regimens had significant effect on overall water:feed ratios with FR>(AL=WR)>FWR. Restriction of feed and/or water resulted in marked elevation of H/L ratios. As measured by H/L ratios, the effect of adapting to FR dissipated between 16 to 21 days after the onset of feed restriction. The H/L ratios of WR and FWR birds remained elevated throughout the duration of the experiment.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.20 no.1
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• pp.19-25
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• 2012

The air traffic situation variables were emphasized in this research to review the awareness level of job performance of military air traffic controllers in application of air traffic situation variables such as detection of aircraft identification, type of aircraft, position ,speed, altitude, determination of separation between departing and arriving in-trail aircraft, physical airport conditions, adverse weather conditions, NAVAID outage and ATC facilities' operational status. In this respect, This study was conducted under the auspice of ATC facility operating agencies and devoting air force air traffic controller's participation by answering the questionnaires from nine radar approach control facilities and other air traffic control towers.