• International Journal of Naval Architecture and Ocean Engineering
• /
• v.8 no.6
• /
• pp.563-576
• /
• 2016

The flight deck of an aircraft carrier is relatively vulnerable compared to its hull, as the damage of some subsystems on the flight deck may cause the carrier losing its operational capability. Therefore, this work aims to represent a simulative method for evaluating the resistance of the flight deck's operational capability in the condition that the aircraft carrier is together with its strike group and the enemy uses the anti-ship missiles with the cluster warheads to attack. In the simulations, the susceptibility of the carrier and the vulnerability of the aircraft guarantee resources are gained. Then, with the help of the closed queuing network, the residual sortie generation rate can be solved, which reflects the flight deck's residual operational capability. The results have proven that the flight deck is of strong resistance to these attacks while it is very sensitive to the loss of some key aircraft guarantee resources.

• 한국신재생에너지학회:학술대회논문집
• /
• 2006.06a
• /
• pp.419-423
• /
• 2006

Basic studies on natural gas hydrates in the East Sea were been carried out by the Korea Institute of Geoscience and Mineral Resources (KIGAM) from 2000 to 2004 involving 2D multichannel seismic lines and piston coring. 27 piston cores recovered from the deed-water Ulleung Basin of the East Sea were analyzed in this study. In piston cores cracks generally developed parallel to bedding suggest significant gas content. The core analyses showed high total organic carbon (TOC) content, sedimentation rate and heat flow of sediments. The cores recovered from the southern study area show also high residual hydrocarbon gas concentrations for the formation of natural gas hydrates. This study indicates that there is the potential for the generation of biogenic gas and the formation of natural gas hydrates in the near seafloor sediments of the study area.

• Korean journal of applied entomology
• /
• v.31 no.4
• /
• pp.536-542
• /
• 1992

Control effects of carbofuran soil incorporation just before transplanting on the early occur-ring rice insect pests were studied in the rice field. Also, its residual effects on the brown planthopper (BPH) were studied by pot experiments. Carbofurn soil incorporation in late May was much more effective in controlling the early occurring rice insect pests such as small brown planthopper, green leafhopper and rice stem borer than carbofuran broadcasting or diazinon (3G) + BPMC (50% EC) treatment in mid June. Residual effects of carbofuran soil incorportaion on the female adult BPH decreased ca. a half one month after treatment. However, its residual effects on the next generation of the BPH lasted much longer; control effects on the next generation were above 90 and 70% on 37 and 46 days after treatment, respectively. From these results, it is thought that carbofuran soil incorporation just before rice transplanting can be a good control method to the early occurring rice insect pests and the brown planthopper immigrating during June. Also, it can suppress immigrating BPH popula¬tion moderately in early July.

• Journal of the Korean Society of Industry Convergence
• /
• v.7 no.1
• /
• pp.55-62
• /
• 2004

The presence of cutting fluid for cutting tool and workpiece leads a temperature decrease, and reduces tool wear and residual stress. Moreover, it disposes chips from cutting area, and reduces thermal distortion. However, in manufacturing, cutting fluid used in cutting process is undesirable for both human and environmental aspect. Also, it's not economic for cutting cost. This paper studied experimentally the effects of cutting parameters on the characteristics of mist generation in turning. The results of experiment are as follows: 1) The more severe cutting conditions the more mist generate, 2) The ratio of weight concentrations of cutting fluid nearly have no an effect on the amounts of mist generation 3) The size of SMD is not affected by cutting parameters.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.40 no.5
• /
• pp.535-546
• /
• 2020

Land cover maps are derived from satellite and aerial images by the Ministry of Environment for the entire Korea since 1998. Even with their wide application in many sectors, their usage in research community is limited. The main reason for this is the map compilation cycle varies too much over the different regions. The situation requires us a new and quicker methodology for generating land cover maps. This study was conducted to automatically generate land cover map using aerial ortho-images and Landsat 8 satellite images. The input aerial and Landsat 8 image data were trained by Residual U-Net, one of the deep learning-based segmentation techniques. Study was carried out by dividing three groups. First and second group include part of level-II (medium) categories and third uses group level-III (large) classification category defined in land cover map. In the first group, the results using all 7 classes showed 86.6 % of classification accuracy The other two groups, which include level-II class, showed 71 % of classification accuracy. Based on the results of the study, the deep learning-based research for generating automatic level-III classification was presented.

• Journal of Broadcast Engineering
• /
• v.17 no.5
• /
• pp.734-741
• /
• 2012

A new lossless intra coding method based on residual transform is applied to the next generation video coding standard HEVC (High Efficiency Video Coding). HEVC includes a multi-directional spatial prediction method to reduce spatial redundancy by using neighboring samples as a prediction for the samples in a block of data to be encoded. In the new lossless intra coding method, the spatial prediction is performed as samplewise DPCM (Difference Pulse Code Modulation) but is implemented as block-based manner by using residual transform and secondary residual transform on the HEVC standard. Experimental results show that the new lossless intra coding method reduces the bit rate by approximately 6.45% in comparison with the lossless intra coding method previously included in the HEVC standard.

• Journal of Institute of Control, Robotics and Systems
• /
• v.9 no.11
• /
• pp.883-890
• /
• 2003

Two GOS (Generalized Observer Scheme) type Fault Detection Isolation Schemes (FDIS), employing the bank of unknown input functional observers (UIFO) as a residual generator, are proposed to make the practical use of the multiple observer based FDIS. The one is IFD (Instrument Fault Detection) scheme and the other is PFD (Process Fault Detection) scheme. A design method of UIFO is suggested for robust residual generation and reducing the size of the observer bank. Several design objectives that can be achieved by the FDI schemes and the design methods to meet the objectives are described. An IFD system is constructed for the Boeing 929 Jetfoil boat system to show the effectiveness of the propositions. Major contributions of this paper are two folds. Firstly, the proposed UIFO approaches considerably reduce the size of residual generator in the GOS type FDI systems. Secondly, the FDI schemes, in addition to the basic functions of the conventional observer-based FDI schemes, can reconstruct the failed signal or give the estimates of fault magnitude that can be used for compensating fault effects. The schemes are directly applicable to the design of a fault tolerant control systems.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.6 no.4
• /
• pp.108-117
• /
• 1997

A continuum analysis has been performed for the application to the thermo-elasto-plastic behavior in a discontinuous metal matrix composite. an FEM (Finite Element Method) analysis was implemented to obtain the internal field quantities of composite as well as overall composite behavior and an experiment was demonstrated to compare with the numerical simulation . As the procedure, a reasonably optimized FE mesh generation, the appropriate imposition of boundary condition , and the relevant post processing such as elastoplastic thermomchanical analysis were taken into account. For the numerical illustration, an aligned axisymmetric single fiber model with temperature dependent material properties and precipitation hardening effect has been employed to assess field quantities. It was found that the residual stresses are induced substantially by the temperature drop during the thermal treatment and that the FEM results of the vertically and horizontally constrained model give a good agreement with experimental data.with non-woven carbon mat is about 24% higher than that of composite materials without non-woven carbon mat. Transverse tensile strength and torughness also increase by inserting non-woven carbon mat between layers.

• Journal of Korea Foundry Society
• /
• v.40 no.1
• /
• pp.1-6
• /
• 2020

Many studies involving a thermal stress analysis using computational methods have been conducted, though there have been relatively few experimental attempts to investigate thermal stress phenomena. Casting products undergo thermal stress variations during the casting process as the temperature drops from the melting temperature to room temperature, with gradient cooling also occurring from the surface to the core. It is difficult to examine thermal stress states continuously during the casting process. Therefore, only the final states of thermal stress and deformations can be detemined. In this study, specimens sensitive to thermal stress, were made by a casting process. After which the residual stress levels in the specimens were measured by a hole drilling method with Electron Speckle-Interferometry technique. Subsequently, we examined the thermal stresses in terms of deformation during the casting process by means of a numerical analysis. Finally, we compared the experimental and numerical analysis results. It was found that the numerical thermal stress analysis is an effective means of understanding the stress generation mechanism in casting products during the casting process.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.41 no.1
• /
• pp.29-36
• /
• 2017

The paper presents a basic investigation for the development of cleaning technology employing an annular nozzle ejector for application to cleaning water supply and air bubble generation. The quantitative flow characteristics of the primary and suction flows, the qualitative visualization behavior of the mixed jet, and the percentage concentration of pesticide residual at different values of the ejector screw pitch were investigated. It was seen that the primary flow rate increased, while the mass ratio decreased with increase in screw pitch. Further, the mixed jet behaved like a buoyancy jet or horizontal bubbly jet, and the residual concentration of pesticide first decreased and then increased with increase in screw pitch.