• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.147-150
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• 2006

The influences of injection conditions and recess configuration of liquid-liquid swirl coaxial injector on spray characteristics were investigated. The characteristics of the coaxial spray in internal mixing injection region were mai y controlled by the merging phenomenon and momentum balance between two liquid sheets, but those in internal mixing injection region were influenced by the impingement phenomenon as well as momentum balance between two liquid sheets.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.3
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• pp.1-8
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• 2006

The influences of injection conditions and recess configuration of liquid-liquid swirl coaxial injectors on spray characteristics were investigated. The characteristics of the coaxial spray in internal mixing injection region were mainly controlled by the merging phenomenon and momentum balance between two liquid sheets, but those in internal mixing injection region were influenced by the impingement phenomenon as well as momentum balance between two liquid sheets.

• Journal of Korea Multimedia Society
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• v.13 no.5
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• pp.651-662
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• 2010

This paper describes a method to identify objects for autonomous navigation of an outdoor mobile robot. To identify objects, the robot recognizes the object from an image taken by moving robot on outdoor environment. As a beginning, this paper presents the candidates for a segment of region to building of artificial object, sky and trees of natural objects. Then we define their characteristics individually. In the process, we segment the regions of the objects included by preprocessing using multiple features. Multiple features are HSI, line segments, context information, hue co-occurrence matrix, principal components and vanishing point. An analysis of building identifies the geometrical properties of building facet such as wall region, windows and entrance. The building as intersection in vertical and horizontal line segment of vanishing point extracts the mesh. The wall region of building detect by merging the mesh of the neighbor parallelograms that have similar colors. The property estimates the number of story and rooms in the same floors by merging skewed parallelograms of the same color. We accomplish the result of image segmentation using multiple features and the geometrical properties analysis of object through experiments.

• Applied Biological Chemistry
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• v.39 no.6
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• pp.488-493
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• 1996

As a first step of pesticide runoff studies, runoff losses of captafol were measured under natural rainfall conditions in apple orchard area. The maximum concentration of captafol was 180 ppb at 5 th sampling period when the rainfall occurred within 24 hours after captafol was applied, and the concentration of samples from other periods was below than 20 ppb. Total runoff loss of captafol was below 0.1%. About 10 fold of dilution factor was observed at the merging point with stream near outlet from orchard and about 50 fold was observed at the next merging point which is located further down. Therefore, captafol will not harm the aquatic organisms due to dilution factor$(10{\sim}50\;fold)$ and rapid hydrolytic degradation rate even when it was run off into a stream nearby.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.5
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• pp.229-236
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• 2023

Since 3D printed medical implant parts usually have surface defects, it is necessary to inspect the surface after manufacturing. In order to automate the surface inspection, it is effective to 3D scan the implant and reconstruct it as a scan model such as a point cloud. When constructing a scan model, the characteristics of the shape and material of the implant must be considered because it has characteristics different from those of general 3D printed parts. In this paper, we present a method to reconstruct the 3D scan model of a 3D printed metal bone-plate that is one kind of medical implant parts. Multiple partial scan data are produced by multi-view 3D scan, and then, we reconstruct a scan model by alignment and merging of partial data. We also present the process of the scan model reconstruction through experiments.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.10
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• pp.2779-2786
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• 1994

This study presents an experimental investigation of the effect of the wake on mass transfer about a circular cylinder in crossflow. The flat-plate wake was generated by merging two mirror images of turbulent boundary layers that were well developed along the both sides of flat plate with a sharp trailing edge. The velocity field was measured by a hot-wire system and the mass transfer rate by a naphthalene sublimation method. The mixing and developing stages of the wake were addressed to identify flow conditions. The mass transfer effects of different developing stages of the wake was discussed in detail. It is noted that a local maximum appears not at the front stagnation point but at a point a little downstream when the cylinder is located in the nearwake region and much more elevated mass transfer rate is obtained compared to effect of free-stream turbulence.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.6
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• pp.102-108
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• 2011

The flow characteristics of unventilated dual impinging jets were experimentally investigated. Two nozzles with an aspect ratio of 20 were separated by 6 nozzle widths. The Reynolds number based on nozzle width and nozzle exit velocity was set to 5,000. A Particle Image Velocimetry (PIV) was used to measure turbulent velocity components. It was found that, when an impingement plate was installed in the converging region, there was a stagnation region in the inner area between nozzles. However, when it was installed in the combined region, both jets were merged and collided into the plate, showing single-jet characteristics. In addition, at a dual impinging jet, as the distance between a nozzle and an impingement plate decreased, the spanwise turbulent intensity at the plate increased.

• Journal of Conservation Science
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• v.28 no.1
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• pp.87-94
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• 2012

This study was focused on digital restoration and surface depth modeling applying the three-dimensional laser scanning system of the Haeundae Stone Inscription. Firstly, the three-dimensional digital restoration carried out acquiring of point cloud using wide range and precision scanner, thereafter registering, merging, filtering, polygon mesh and surveyed map drawing. In particular, stroke of letters, inscribed depth and definition appearing the precision scanning polygon was outstanding compared with ones of the wide range polygon. The surface depth modeling completed through separation from polygon, establishment of datum axis, selection of datum point, contour mapping and polygon merging. Also, relative inscribed depth (5~17mm) and outline by the depth modeling was well-defined compared with photograph and polygon image of the inscription stone. The digital restoration technology merging wide range and precision scanning restored the total and detailed shape of the Stone Inscription quickly and accurately. In addition, the surface depth modeling visibly showed unclear parts from naked eye and photograph. In the future, various deteriorations and surrounding environment change of the Stone Inscription will be numerically analyze by periodic monitoring.

• Journal of Korean Society of Transportation
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• v.27 no.4
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• pp.115-126
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• 2009

The lane-change behavior usually consists of discretionary lane-change and mandatory lane-change types. For the first type, drivers change lanes selectively to maintain their own driving condition and the second type is the case that the drivers must change the current lane, which can occur in recurrent congestion sections like merging and weaving sections. The mandatory lane-change behavior have a great effect on the operation condition of freeway. In this paper, we first generate data such as traffic volumes, speeds, densities, and the number of lane-change within the merging and weaving sections using the data of individual vehicle collected from time-lapse aerial photography. And then, the data is divided into the stable and congested flow by analyzing the speed variation pattern of individual vehicles. In addition, the number of lane-changing from ramp to mainline within every 30-meter interval is investigated before and after traffic congestion at study sites and the distribution of lane-changing at each 30-meter point is analyzed to identify the variation of lane-changing ratio depending on the stable and congested flows. To recognize the effect of mainline flow influenced by ramp flow, this study also analyzes the characteristics of the lane-changing distributions within the lanes of mainline. The purpose of this paper is to present the basic theory to be used in developing a lane-changing model at the merging and weaving sections on freeways.

• Journal of the Korean earth science society
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• v.31 no.6
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• pp.555-562
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• 2010

Three-dimensional laser scanner was used to accurately measure any possible strain on a slope under pertaining stress with the time difference of 7 months. The laser scanner has the ability to measure the 3-D coordinate of a target point by calculating the travel time of laser beam between the laser device and the target point, and has been proved to be effective for analysis of the displacement of slopes or large construction. The scanning data measured with time difference were analyzed to find any strain by approaches of plane angle change, curvature variation, twist of frame, displacement of merging point, etc. From the analysis, some weak points showing heavily distorted shape were detected, which was used to design the reinforcement.