• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.348-349
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• 2006

The plastic deformation behavior of cemented carbides is related to the WC grain boundary strength. Ab initio calculations predict that Co and Mn segregate to WC/WC grain boundaries. To experimentally study the effect of Mn, a WC-Co-Mn material was manufactured and compared to a WC-Co material. The microstructure was studied using scanning electron microscopy (SEM), including electron backscatter diffraction (EBSD). Special attention was paid to the WC grain size and the frequency of special low-energy grain boundaries. Mn was found to have negligible effect on both the WC grain growth and the fraction of $\sum2$ WC/WC boundaries in the as-sintered material.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.95-96
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• 2013

Numerical simulations are conducted to investigate the mechanism of spontaneous ignition of hydrogen within a certain length of downstream pipe released by the failure of pressure boundaries of various geometric assumption. The results show that local ignition is developed in limited area such as boundary layer and the mixing of hydrogen and air is weak at the planar pressure boundary conditions, whereas the flame fronts at the contact region are developed at the pressure boundaries of the spherical shape.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.2
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• pp.63-69
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• 2017

The extraction of attention NPC in a FPS game has emerged as a very significant issue. We propose an efficient FPS game operation method, using the attention NPC extraction with a simple arithmetic. First, we define the NPC, using the color histogram interaction and texture similarity in the block to determine the attention NPC. Next, we use the histogram of movement distribution and frequency of movement of the NPC. Becasue, except for the block boundary according to the texture and to extract only the boundaries of the object block. The edge strength is defined to have high values at the NPC object boundaries, while it is designed to have relatively low values at the NPC texture boundaries or in interior of a region. The region merging method also adopts the color histogram intersection technique in order to use color distribution in each region. Through the experiment, we confirmed that NPC has played a crucial role in the FPS game and as a result it draws more speed and strategic actions in the game.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.4
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• pp.255-262
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• 2020

Grain boundaries play a major role in determining device performance, particularly of polysilicon-based photodetectors. Through the post-annealing of as-deposited polysilicon and then, the analysis of electric behavior for a metal-polysilicon-metal (MSM) photodetector, we were able to identify the influence of grain boundaries. A modified model of polysilicon grain boundaries in the MSM structure is presented, which uses a crystalline-interfacial layer-SiO_x layer- interfacial layer-crystalline system that is similar to the Si-SiO₂ system in MOS device. Hydrogen passivation was achieved through a hydrogen ion implantation process and was used to passivate the defects at both interfacial layers. The thin SiO_x layer at the grain boundary can enhance the photosensitivity of an MSM photodetector by decreasing the dark current and increasing the light absorption.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.05a
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• pp.4-4
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• 2003

Various Cu films were fabricated using sputtering and electroplating with and without additive, and their surface damages after annealing were investigated. After annealing at 43SoC, the difference between damage morphologies of the films was observed. In some films stress-induced grooves along the grain boundaries were observed, while in the others voids at the grain boundary triple junctions were observed. It was also observed that the stress-induced groove was formed along the high energy grain boundaries. It was found out that the difference of the morphologies of surface damages in Cu films depends on not process type but grain boundary characteristics. To explain the morphological difference of surface damages, a simple parameter considering the contributions of grain structures and grain boundary characteristics to surface and grain boundary diffusions is suggested. The effective grain boundary area, which is a function of grain size, film thickness and the fraction of high energy grain boundaries, played a key role in the morphological difference.

• Korean Journal of Remote Sensing
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• v.23 no.3
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• pp.199-209
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• 2007

Traditionally, aerial images have been used as main sources for compiling topographic maps. In recent years, lidar data has been exploited as another type of mapping data. Regarding their performances, aerial imagery has the ability to delineate object boundaries but omits much of these boundaries during feature extraction. Lidar provides direct information about heights of object surfaces but have limitations with respect to boundary localization. Considering the characteristics of the sensors, this paper proposes an approach to extracting buildings from lidar and aerial imagery, which is based on the complementary characteristics of optical and range sensors. For detecting building regions, relationships among elevation contours are represented into directional graphs and searched for the contours corresponding to external boundaries of buildings. For generating building models, a wing model is proposed to assemble roof surface patches into a complete building model. Then, building models are projected and checked with features in aerial images. Experimental results show that the proposed approach provides an efficient and accurate way to extract building models.

• Korean Journal of Remote Sensing
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• v.23 no.3
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• pp.221-227
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• 2007

We present an analysis of urban development and growth with reconnaissance satellite photographs of Columbus metropolitan area acquired by the Corona program in 1965. A two-dimensional polynomial linear transformation was used to rectify the photos against United State Geological Survey (USGS) Large-scale Digital Line Graph (DLG) data georeferenced to Universal Transverse Mercator (UTM) coordinates. The boundaries of the Columbus metropolitan area were extracted from the rectified Corona image mosaic using a Bayesian approach to image segmentation. The inferred 1965 urban boundaries were compared with 1976 USGS Land Use and Land Cover (LULC) data and boundaries derived from 1988 and 1994 Landsat TM images. The urban area in and around Columbus approximately doubled from 1965 to 1994 (${\sim}110%$) along with population growth from 1960 to 1998 (${\sim}50%$). Most of the urban expansion results from development of residential units.

• Korean Journal of Remote Sensing
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• v.11 no.2
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• pp.43-57
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• 1995

This paper presents reconstruction of disparity in images. To achieve this, the algorithm was made up of two different procedures - one is extraction of boundaries for man-made structures and the other is matching of the structures. In the extraction of boundaries for man-made structures, we assume that man-made structures are composed of lines and the lines make up closed polygon. The convertional algorithms of the edges extraction may not perceive man-made structures and have problems that matching algorithms were too complex. This paper proposed sub-pixel boundaries extraction algorithm that fused split-and-merge and image improvement algorithms to overcome complexity. In matching procedure, feature-based algorithm that minimize the proposed cost function are used and the cost fuction considers movement of mid-points for left and right images to match structures. Because we could not obtain disparity of inner parts for the man-made structures, interpolation method was used. The experiment showed good results.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.4
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• pp.114-122
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• 1995

In this paper a computational method is presented to solve the plane problem of wave propagation in linear-elastic plate with zones of different materials. An existing numerical scheme of bicharacteristics for rectangular plate is extended to plates with curvilinear boundaries. In order to show the validity of the employed concept, it is necessary to examine the numerical results whether they reproduce the well-known physical phenomena of stress waves. It seems also desirable to make a comparison between the numerical results and appropriate experimental results for plates with curvilinear boundaries. Also studied are the focusing phenomena induced by reflection and refraction at curved outer boundaries and material interfaces.

• Journal of Magnetics
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• v.18 no.3
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• pp.348-351
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• 2013

Inconel 600 alloy, Ni base alloy, is widely used for steam generator tubings where sensitization occurs at grain boundaries and sensitization will induce tubing failures. This alloy has usually paramagnetic property, however, it transforms into ferromagnetic property along grain boundaries when sensitization occurs: this means NDE using magnetism for sensitization is possible. Therefore, in this study, Inconel 600 alloys were heat treated at 873 K from 0 to 400 hours so as to generate sensitization and their magnetic properties were investigated in detail. The saturation and the residual magnetization increase with increasing heat treatment time and take a maximum. On the other hand, the coercive force decreases with the increase in time of heat treatment. We confirmed that characteristics at only grain boundaries change into ferromagnetic phase by a MFM observation. As a trial for industrial application, heat treated Inconel 600 alloy was scanned by a magnetic field sensor, and the variations in magnetization were obtained nondestructively. The results indicate a feasibility of magnetic NDE for sensitization of Inconel 600 alloy.