• Imaging Science in Dentistry
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• v.34 no.3
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• pp.129-136
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• 2004

Purpose: To evaluate whether cone beam computed tomography can depict the distribution, position, frequency, relative vertical dimension, and the diameter of the lingual foramen and direction of lingual bone canal. Materials and Methods : Cone beam computed tomography of mandible was performed on 25 males and 25 females with no history of any orthodontic treatments or any other dental surgeries. A statistical comparison was done on the mean values of males and females. Results: In the location and distribution of lingual foramina, median lingual foramen was found in all subjects and lateral lingual foramen in 58%. In the lateral lingual foramen, bilateral type was found in 28% and unilateral type in 30%. In the number of lingual foramina, median lingual foramen had two foramina and lateral lingual foramen had one foramen, mostly. In the relative mean vertical dimension of lingual foramina, median lingual foramen was 0.03±0.08, and both lateral lingual foramina was 0.20±0.04. The mean diameter of lingual foramina, median lingual foramen was 0.9mm±0.28, right lateral lingual foramen was 0.92mm±0.23, and left lateral lingual foramen was 0.88mm±0.27. The most frequent direction of the lingual bone canals, median lingual bone canal proceeded in anteroinferior direction and lateral lingual bone canal in anterosuperolateral direction. Conclusion : Cone beam computed tomography can be helpful for surgery and implantation on the mandibular area. Radiologist should be aware of this anatomical feature and its possible implications.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.5
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• pp.59-67
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• 2004

Gait is defined as a manner or characteristics of walking. Recently, the study on extracting features of the gait to identify the individual has been progressed actively, within the computer vision community. Even if the camera is fixed, gait features extracted from images are varied according to the direction of walking. In this paper, we propose the method which compensates for the drawback of the gait recognition which is dependant on the direction. First, we search a direction of walking and estimate the planar homography with simple operations. Through synthesizing canonical viewed images by using the estimated homography, viewpoint variation by the direction of walking is compensated. In this paper, we segment gait silhouette into sub-regions and use averaged feature and its variation of each region to recognition experiment. Experimental results show that the proposed method is robust for directional variation of the gait.

• Korean Journal of Remote Sensing
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• v.36 no.5_2
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• pp.989-1006
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• 2020

Building change monitoring based on building detection is one of the most important fields in terms of monitoring artificial structures using high-resolution multi-temporal images such as CAS500-1 and 2, which are scheduled to be launched. However, not only the various shapes and sizes of buildings located on the surface of the Earth, but also the shadows or trees around them make it difficult to detect the buildings accurately. Also, a large number of misdetection are caused by relief displacement according to the azimuth and elevation angles of the platform. In this study, object-based building detection was performed using the azimuth angle of the Sun and the corresponding main direction of shadows to improve the results of building change detection. After that, the platform's azimuth and elevation angles were used to detect changed buildings. The object-based segmentation was performed on a high-resolution imagery, and then shadow objects were classified through the shadow intensity, and feature information such as rectangular fit, Gray-Level Co-occurrence Matrix (GLCM) homogeneity and area of each object were calculated for building candidate detection. Then, the final buildings were detected using the direction and distance relationship between the center of building candidate object and its shadow according to the azimuth angle of the Sun. A total of three methods were proposed for the building change detection between building objects detected in each image: simple overlay between objects, comparison of the object sizes according to the elevation angle of the platform, and consideration of direction between objects according to the azimuth angle of the platform. In this study, residential area was selected as study area using high-resolution imagery acquired from KOMPSAT-3 and Unmanned Aerial Vehicle (UAV). Experimental results have shown that F1-scores of building detection results detected using feature information were 0.488 and 0.696 respectively in KOMPSAT-3 image and UAV image, whereas F1-scores of building detection results considering shadows were 0.876 and 0.867, respectively, indicating that the accuracy of building detection method considering shadows is higher. Also among the three proposed building change detection methods, the F1-score of the consideration of direction between objects according to the azimuth angles was the highest at 0.891.

• Journal for History of Mathematics
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• v.18 no.2
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• pp.23-30
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• 2005

Intuition has played an important role in process of invention of mathematics and given understanding of mathematical truth and the direction of solution. So, I review about intuition in history of mathematical philosophy and mathematics because we need systematic research about intuition for search of the methods for enhancement of intuition in mathematics education. According to the research of scholars who emphasize intuitive education, intuition is common feature which everybody hold and is not special feature which particular person hold. In addition, intuition is universal ability that can enhance by proper instruction. So, we have to emphasize the importance of the development of intuition and education which emphasize creative thought via intuition.

• International Journal of Precision Engineering and Manufacturing
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• v.2 no.3
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• pp.41-46
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• 2001

This paper discusses the feasibility of improving micro-machining accuracy by using two-dimensional(2-D) vibration cutting. Vibration cutting is generated by two piezo actuators arranged orthogonally : one is actuated by a sine curve voltage input, and the other is actuated by a phase-shifted sine curve voltage. A tool attached to the vibrator oscillates in a 2-D elliptical motion, depending on the frequencies, amplitudes, and the phase shifts of two input signals and the workpiece feedrate. Along the elliptical tool locus, cutting is done in the lower part, and non-cutting is done in the upper part. By this way a unique feature of 2-D vibration cutting, that is, air lubrication between a tool and chips, is caused. Another unique feature of 2-D vibration cutting was experimentally verified, that is, some negative thrust force occurs as the direction of chip movement on a tool rake face is reversed. Those features not only help chips flow smoothly and continuously but also reduce cutting force, which results in a higher quality machined surface. Through tool path simulations and experiments under several micro-machining conditions, the 2-D vibration cutting, compared to conventional cutting, was found to result in a great decrease in the cutting force, a much smoother surface, and much less burr.

• The Journal of the Korea Contents Association
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• v.20 no.8
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• pp.359-367
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• 2020

WSNs as the main technology of IoT often deliver information or authenticate based on location. Thus, verifying location information is essential. This paper aims to present the comprehensive analysis and classification of location verification techniques in WSN. For this, classification criteria are suggested based on the result of feature analysis of existing techniques. In addition, the existing techniques are classified according to the suggested criteria, and each characteristic and development direction are described. The result of this paper is expected to be a useful reference material when designing a new technique.

• The Journal of Korea Robotics Society
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• v.7 no.2
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• pp.120-128
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• 2012

The loop closure problem is one of the most challenging issues in the vision-based simultaneous localization and mapping community. It requires the robot to recognize a previously visited place from current camera measurements. While the loop closure often relies on visual bag-of-words based on point features in the previous works, however, in this paper we propose a line-based method to solve the loop closure in the corridor environments. We used both the floor line and the anchored vanishing point as the loop closing feature, and a two-step loop closure algorithm was devised to detect a known place and perform the global pose correction. We propose an anchored vanishing point as a novel loop closure feature, as it includes position information and represents the vanishing points in bi-direction. In our system, the accumulated heading error is reduced using an observation of a previously registered anchored vanishing points firstly, and the observation of known floor lines allows for further pose correction. Experimental results show that our method is very efficient in a structured indoor environment as a suitable loop closure solution.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.149-152
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• 2009

Spray characteristic parameters such as droplet mean velocity, diameter, and volume flux are measured at various locations of spray in order to investigate the evolutionary feature of droplets exiting from a direct-injection type thruster nozzle-orifice. The experimental results indicate that the large droplets with high velocity at the center of upstream are broken-up into smaller droplets with low velocity due to their continuous momentum loss to surrounding air along with spray evolution toward downstream. Also it is found that the high volume flux expands its distribution in radial direction as a results of spray spreading and dispersion.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.453-454
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• 2015

IoT is field that to create a globally huge added value is expected. In the game field, a game have appeared utilizing a variety of platforms based on the IoT. This paper aims to research on developed in IoT based platform, and to understand the feature of the released games in domestic. After many literature related to IoT reviewed, we understanded feature how the case studies that have been applications in IoT based games. In this study, become the guideline of game research of IoT-based platform, expect to present the direction of the IoT based game development.

• Convergence Security Journal
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• v.14 no.7
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• pp.23-28
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• 2014

This study proposes the design and implementation of the system for a facial expression recognition system. LDP(Local Directional Pattern) feature computes the edge response in a different direction from a pixel with the relationship of neighbor pixels. It is necessary to be estimated that LDP code can represent facial features correctly under various conditions. In this respect, we build the system of facial expression recognition to test LDP performance quickly and the proposed evaluation system consists of six components. we experiment the recognition rate with local micro patterns (LDP, Gabor, LBP) in the proposed evaluation system.