• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.5
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• pp.1096-1105
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• 1994

A hypereutectic Aluminum-Silicon Alloy is widely used in the parts of automobile because of high-resistance and good strength. In this study, the cutting of hypereutectic A1-Si alloy for economical production was investigated by simulation. Tool life and the extraction rate of Si particles is inversely proportional to the depth of cut. When decreasing the depth of cut, the reduction of single crystal diamond tool cost and tool change time is achieved.

• Journal of Multimedia Information System
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• v.5 no.3
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• pp.189-194
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• 2018

In this paper, we propose the drowsiness detection method for car driver. This paper determines whether or not the driver's eyes are closed using the depth and infrared videos. The proposed method has the advantage to detect drowsiness without being affected by illumination. The proposed method detects a face in the depth picture by using the fact that the nose is closest to the camera. The driver's eyes are detected by using the extraction of harr-like feature within the detected face region. This method considers to be drowsiness if eyes are closed for a certain period of time. Simulation results show the drowsiness detection performance for the proposed method.

• Proceedings of the Costume Culture Conference
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• 2005.10a
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• pp.48-54
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• 2005

In order to mass-customize clothes, it is essential to take into account individual body shape using computerized 3D body models. This paper describes the development of an interactive body model that can be altered to match individual body perimeter, postures and depth for the purpose of computerized pattern making. Construction of the body model requires the extraction of necessary points, adjustment of coordinate points, linking of points by spline curves, control of section lengths and selectability of various hip types. Front to back depth of the model is adjusted by scaling ratio. We had a great result for controlling perimeter, posture and depth of body shapes. The results support the adaptability and potential usefulness of the posture and depth adjustable body model.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.5
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• pp.408-412
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• 2010

Introduction: This study examined the depth of sedation and the usefulness of the monitoring tool in determining the level of sedation in patients undergoing third molars extraction under conscious sedation with midazolam. Materials and Methods: Twenty two patients undergoing third molars extraction at the department of Oral and Maxillofacial surgery, Ewha Womans Mokdong Hospital from February 2010 to April 2010 were analyzed. All patients were classified as American Society of Anesthesiologist (ASA) class I and had no contraindications tosedation. The bispectral index was recorded continually during surgery using a bispectral monitor. The initial sedation was accomplished using a 3 mg bolus of midazolam followed by a 2 mg bolus of midazolam until the level of sedation, at which the patient’s eyes were closed or the subject was responsive only to loud or repeated calling of their name, was reached. All subjects were surveyed with a postoperative questionnaire to evaluate the level of sedation. Results: The bispectral index (BIS) decreased approximately 5 minutes after midazolam administration, but increased at the local anesthesia injection and odontomy procedure. The amnestic effect was shown effectively in the early stages of surgery. Conclusion: Conscious sedation with intravenous midazolam is effective in achieving the effect of anxiolysis, analgesia and amnesia. The BIS is an objective and useful means of assessing the depth of sedation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.5
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• pp.328-334
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• 2020

Objectives: This study aimed to validate the effectiveness of a recently proposed difficulty index for removal of impacted mandibular third molars based on extraction time and suggest a modified difficulty index including the presence of pathologic conditions associated with third molars. Materials and Methods: This retrospective study enrolled 65 male patients younger than 25 years with third molars. Extraction time was calculated from start of the incision to the last suture. The difficulty scores for third molars were based on spatial relationship (1-5 points), depth (1-4 points), and ramus relationship (1-3 points) using cone-beam computed tomography. The difficulty index was defined as follows: I (3-4 points), II (5-7 points), III (8-10 points), and IV (11-12 points). The modified difficulty score was calculated by adding one point to the difficulty score if the third molar was associated with a pathologic condition. Two modified difficulty indices, based on the presence of pathologic conditions, were as follows: the half-level up difficulty index (HDI) and the one-level up difficulty index (ODI) from the recently proposed difficulty index. Results: The correlations between extraction time and difficulty index and or modified difficulty indices were significant (P<0.001). The correlation coefficient between extraction time and difficulty index was 0.584. The correlation coefficients between extraction time and HDI and ODI were 0.728 and 0.764, respectively. Conclusion: Extraction time of impacted third molars exhibited a moderate correlation with difficulty index and was strongly correlated with the modified indices. Considering the clinical implications, the difficulty index of surgical extraction should take into consideration the pathologic conditions associated with third molars.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.7
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• pp.1369-1375
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• 2016

In this paper, we present a depth extraction method of integral imaging using correlation between elemental images with phase only filter. Integral imaging is a passive three-dimensional (3D) imaging system records ray information of 3D objects through lenslet array by 2D image sensor, and displays 3D images by using the similar lenslet array. 2D images by lenslet array have different perspectives. These images are referred to as elemental images. Since the correlation can be calculated between elemental images, the depth information of 3D objects can be extracted. To obtain high correaltion between elemental images effectively, in this paper, we use phase only filter. Using this high correlation, the corresponding pixels between elemental images can be found so that depth information can be extracted by computational reconstruction technique. In this paper, to prove our method, we carry out optical experiment and calculate Peak Sidelobe Ratio (PSR) as a correlation metric.

• Journal of KIISE:Software and Applications
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• v.31 no.5
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• pp.617-624
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• 2004

This paper describes a new facial feature localization method that uses Adjacent Depth Differences(ADD) in 3D facial surface. In general, human recognize the extent of deepness or shallowness of region relatively, in depth, by comparing the neighboring depth information among regions of an object. The larger the depth difference between regions shows, the easier one can recognize each region. Using this principal, facial feature extraction will be easier, more reliable and speedy. 3D range images are used as input images. And ADD are obtained by differencing two range values, which are separated at a distance coordinate, both in horizontal and vertical directions. ADD and input image are analyzed to extract facial features, then localized a nose region, which is the most prominent feature in 3D facial surface, effectively and accurately.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.41-41
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• 2011

Flash memory에서 tunnel oxide film은 electron tunnelling 현상을 이용하여 gate에 전하를 전달하는 통로로 사용되고 있다. 특히, tunnel oxide film 내부의 charge trap 현상과 불순물이 소자 특성에 직접적인 영향을 주고 있어, 후속 N2O/NO 열처리 공정에서 SiO2/Si 계면에 nitrogen을 주입하여 tunnel oxide film 특성을 개선하고 있다. 따라서 N2O/NO 열처리 공정 최적화를 위해서는 tunnel oxide film 내 N 농도와 분포에 대한 정확한 평가가 필수적이다[1]. 본 실험에서는 low energy magnetic SIMS를 이용하여 N2O로 열처리된 tunnel oxide film 내의 N농도를 보다 정확하게 평가하고자 하였다. 사용된 시료는 Si substrate에 oxidation 이후 N2O 열처리를 진행하여 tunnel oxide를 형성시켰으며, 분석 impact energy는 surface effect최소화와 최상의 depth resolution 확보를 위해 250eV를 사용하였으며, matrix effect와 mass interference를 방지하기 위해 MCs+ cluster mode[2]로 CsN signal를 검출하였다. 실험 결과, 특정 primary beam 입사각도에서 nitrogen depth resolution 저하 현상이 발생하였고, SIMS crater 표면이 매우 거칠게 나타났다. 이에, Depth resolution 저하 현상을 개선하기 위해 극한의 glancing 입사각 조건으로 secondary extraction voltage 변화를 통해 depth resolution이 개선되는 최적의 impact energy와 primary beam 입사각 조건을 확보하였다. 그 결과 nitrogen의 depth resolution은 1.6nm의 depth resolution을 확보하였으며, 보다 정확한 N 농도와 분포를 평가할 수 있게 되었다.

• ETRI Journal
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• v.44 no.1
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• pp.38-50
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• 2022

This paper presents a study on the use of encoder-derived features in decoder-side depth estimation. The scheme of multiview video encoding does not require the transmission of depth maps (which carry the geometry of a three-dimensional scene) as only a set of input views and their parameters are compressed and packed into the bitstream, with a set of features that could make it easier to estimate geometry in the decoder. The paper proposes novel recursive block splitting for the feature extraction process and evaluates different scenarios of feature-driven decoder-side depth estimation, performed by assessing their influence on the bitrate of metadata, quality of the reconstructed video, and time of depth estimation. As efficient encoding of multiview sequences became one of the main scopes of the video encoding community, the experimental results are based on the "geometry absent" profile from the incoming MPEG Immersive video standard. The results show that the quality of synthesized views using the proposed recursive block splitting outperforms that of the state-of-the-art approach.

• Journal of Information Processing Systems
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• v.19 no.4
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• pp.483-497
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• 2023

Depth estimation is one of the most complicated and difficult problems to deal with in the light field. In this paper, a compound attention convolutional neural network (CAttNet) is proposed to extract depth maps from light field images. To make more effective use of the sub-aperture images (SAIs) of light field and reduce the redundancy in SAIs, we use a compound attention mechanism to weigh the channel and space of the feature map after extracting the primary features, so it can more efficiently select the required view and the important area within the view. We modified various layers of feature extraction to make it more efficient and useful to extract features without adding parameters. By exploring the characteristics of light field, we increased the network depth and optimized the network structure to reduce the adverse impact of this change. CAttNet can efficiently utilize different SAIs correlations and features to generate a high-quality light field depth map. The experimental results show that CAttNet has advantages in both accuracy and time.