• Journal of the Korean Society for Precision Engineering
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• v.14 no.3
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• pp.57-65
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• 1997

In this study, a cutting force in the Ball-end milling process is calculated using Z-map. Z-map can describe any type of cutting area resulting from the previous cutting geometry and cutting condition. Cutting edge of a ball-end mill is divided into infinitesimal cutting edge elements and the position of the ele- ment is projected to the cutter plane normal to the Z axis. Also the cutting area in the cutter plane is obtained by using the Z-map. Comparing this projected position with cutting area, it can be determined whether it engages in the cutting. The cutting force can be calculated by numerical integration of cutting force acting on the engaged cutting edge elements. A series of experiments such as contouring and upward/downward ramp cutting was performed to verify the calculated cutting force.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.04a
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• pp.150-155
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• 1997

Rapid Prototyping(RP) is the technique which is used to make prototypes or functional parts directly using the 3-D solid data. Before building the prototype, several processes such as transfering 3D data from CAD system(STL) determination of build-direction, adding support structure and slicing are required. Among the above processes. determination of build-direction is the target of this study. The build direction is determined by many factors according to the objective of the user, like part accuracy, number of support structure, build time, amount of trapped volume, etc, But it is not easy to determine the build-direction because there are many factors and some factors have dependent properties with one another. So, in this study the part accuracy, the number of support structures and build time are considered as the main factor to determine the optimal build-direction. To determine the optimal build-direction for increasing part accuracy, sum of projected area which caused stairstepping effect was considered. The less the projected area is the better part accuracy is About the optimal build-direction to minimize the amount of support structure, sum of projected area of facets that require support structures was considered. About the build time, we considered the minimum height of part we intended. About the build time, we considered the minimun height of part we intended to make.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.125-129
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• 1996

In this study, a method is proposed for the cutting force prediction of Ball-end milling process using Z-map is proposed. Any types of cutting area generated from previous cutting process can be expressed in z-map data. Cutting edge of a ball-end mill is divided into a set of finite cutting edges and the position of this edge is projected to the cross-section plane normal to the Z-axis. Comparing this projected position with Z-map data of cutting area and determining whether it is in the cutting region, total cutting force can be calculated by means of numerical integration. A series of experiments such as side cutting and upward/downard cutting was performet to verify the simulated cutting force.

• Journal of Korean Society of Rural Planning
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• v.25 no.4
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• pp.99-107
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• 2019

This paper analyzed the characteristics of population change from 2000 to 2018 in 466 mountainous areas using resident registration data from the Ministry of the Interior and Safety, and projected the population in those areas through 2050 with the cohort change ratio method. The population had dramatically decreased from 2000 to 2009. With the slowing population decrease after 2010, the population has increased gradually since 2014. Especially the population of ages over 65 in 2018 had increased 34% compared to 2000, while the working age population had decreased 29%. This shows that population aging becomes serious problems in the mountainous area. Assuming the cohort change ratios from 2010 to 2015 and child-woman ratio in 2015 remain constant, it appeared that the projected population of the mountainous area dropped to 1.26 million in 2030 and 820,000 in 2050. It is expected to have a population with an inverted pyramid structure showing a gender imbalance with more females in 60's and 70's. Although it continues to show the recent population growth in mountainous area, population in mountainous area is expected to consistently decrease. Therefore, it is required to develop policies and strategies to promote an influx of people into mountainous area for maintaining functionality and sustainability of mountainous areas.

• Journal of Animal Environmental Science
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• v.5 no.2
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• pp.93-100
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• 1999

Pig's original image data was transformed to a binary image, an image excluding head and tail portion from the whole binary image, and a projected image associated with pig's height. Then the length of body, width of shoulder, and area of pig were calculated and the relationships among the above characteristics and pig's weight were analyzed. The results obtained from this study were as follows: 1. Whole binary image data was considered to be improper to determine the pig's weight because the movement of pig's head and tail portion affected the image data. 2. Binary image data excluding head and tail portion from the whole binary image showed a better estimation of the pig's weight than the whole binary image. 3. Pig's should width was analyzed to be improper factor to determine the pig's weight. 4. The projected image associated with pig's height showed the highest correlation between the pig's area of the image and pig's weight(R2=0.9965). From this research the projected image associated with pig's height, which is excluding head and tail portion from the whole body of pig's image, was considered to be the prime factor to measure the pig's weight by the noncontact measurement.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.3
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• pp.241-247
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• 2012

The national geodetic reference frame of Korea switched to the International Terrestrial Reference Frame (ITRF) in 2003. In order to study the land area changes, we calculated the entire land area of Korea using the administrative boundaries of census data provided by Statistics Korea. The standard transformation procedure by the National Geographic Information Institute (NGII) was followed. The Transverse Mercator (TM) projected coordinates were transformed into the GRS80-based world geodetic reference frame, and the ellipsoidal and the projected areas were calculated. The provinces that range over two projection origins were divided into two polygons and projected using appropriate origins. After the transformation, all boundaries were shifted in the northwestern direction, resulting in a decreased area of $1.36km^2$ (about 0.0013%) on the projected plane. Moving the boundaries into a high latitude area cancels out the effect of the enlarged ellipsoid. In addition, the rate of change shows that a higher-latitude province is more sensitive to the shift of the boundaries. The data by Statistics Korea is significantly different from those of the Ministry of Land, Transport and Maritime Affairs (MLTM), thus it is urgently recommended that the data are integrated and unified.

• Journal of Biosystems Engineering
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• v.15 no.1
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• pp.23-32
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• 1990

Geometrical characteristics of fruit including perimeter, projected area and length of minor and major axis were calculated by computer programs to be used in fruit sorting by image processing system. The results are summerized as follows. 1. A program calculating perimeter, projected area, and length of minor and major axis by edge detection and chain code was developed. 2. Geometrical characteristics of given figures were calculated to verify the program and the discrepancies from the measured values were about 5%. 3. Regression models for estimating volums of apples were developed and regression coefficients for each variety were found. 4. Abnormal apples could be recognized by comparing the ratio of minor axis to major axis and the standard value was proposed.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.2
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• pp.1-8
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• 2002

Cutting force is obtained as a sum of chip removing force and ploughing force. Chip removing force is estimated by multiplying specific cutting pressure by cutting area. Since ploughing force is caused from dullness of a tool, its magnitude is constant if depth of cut is bigger than a certain value. Using the linearity of chip removing force to cutting area and the constancy of ploughing force regardless of depth of cut which is over a certain limit each force is separated from measured cutting force and used to establish cutting force model. New rotation matrix to convert the measured cutting force in reference axes into the forces in cutter axes is obtained by considering that tool angles are projected angles from cutter axes to reference axes.. Spindle tilt is also considered far the model. The predicted cutting force estimated from the model is in good agreement with the measured force.

• Journal of Multimedia Information System
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• v.1 no.2
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• pp.119-126
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• 2014

We propose a bicycle detection system riding on people based on modified projected local binary pattern(PLBP) for vision based intelligent vehicles. Projection method has robustness for rotation invariant and reducing dimensionality for original image. The features of Local binary pattern(LBP) are fast to compute and simple to implement for object recognition and texture classification area. Moreover, We use uniform pattern to remove the noise. This paper suggests that modified LBP method and projection vector having different weighting values according to the local shape and area in the image. Also our system maintains the simplicity of evaluation of traditional formulation while being more discriminative. Our experimental results show that a bicycle and motorcycle riding on people detection system based on proposed PLBP features achieve higher detection accuracy rate than traditional features.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.9
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• pp.2299-2311
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• 2013

As portable multimedia devices become more popular and smaller, the use of portable projectors is also rapidly increasing. However, when portable projectors are used in mobile environments in which a dedicated planar screen is not available, the problem of geometric distortion of the projected image often arises. In this paper, we present a geometric image compensation method for portable projectors to compensate for geometric distortions of images projected on various types of planar or nonplanar projection surfaces. The proposed method is based on extraction of the two-dimensional (2D) geometric information of a projection area, setting of the compensation area, and prewarping using 2D homography. The experimental results show that the proposed method allows effective compensation for waved and arbitrarily shaped projection areas, as well as tilted and bent surfaces that are often found in the mobile environment. Furthermore, the proposed method is more computationally efficient than conventional image compensation methods that use 3D geometric information.