• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.61-67
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• 2016

With the current high distribution rate of smart devices and the recent development of computing technology, user interest in multimedia, such as photos, videos, and so on, has rapidly increased, which is a departure from the simple pattern of information retrieval. Because of these increasing interests, image processing techniques, which generate and process images for diverse applications, are being developed. In entertainment recently, there are some techniques that present a celebrity's image as a mosaic comprising many small images. In addition, studies into the mosaic technique are actively conducted. However, conventional mosaic techniques result in a long processing time as the number of database images increases, because they compare the images in the databases sequentially. Therefore, to increase search efficiency, this paper proposes an algorithm to generate a mosaic image using a discrete cosine transform (DCT) hash. The proposed photo mosaic-generation algorithm is composed of database creation and mosaic image generation. In database creation, it first segments images into blocks with a predefined size. And then, it computes and stores a DCT hash set for each segmented block. In mosaic generation, it efficiently searches for the most similar blocks in the database via DCT hash for every block of the input image, and then it generates the final mosaic. With diverse experimental results, the proposed photo mosaic-creation algorithm can effectively generate a mosaic, regardless of the various types of images and sizes.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.9
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• pp.415-423
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• 2001

Recently, there are many attempts to reproduce real world fine art pieces in digital forms. The digital representations are convenient to store and/or transmit. In contrast, mobiles, or moving sculptures, such as those designed by Alexander Calder cannot to reproduced realistically by usual reproduction techniques. Since mobiles are originally designed to generate motions in response to external forces applied to it, people could not fully enjoy them through photographs or static images. We present a virtual mobile system where use can easily control the mobile and can feel the impressions that the artist originally intended to provide. A real-world mobile is reconstructed in a three-dimensional physically-based model. and then virtual wind is generated to give motions to it. The motions of the mobile are generated by constraint dynamics and impulse dynamics techniques, which are modified to fully utilize the characteristics of the mobile, and finally give interactive displays on the PC platforms. The techniques presented can easily be extended to simulate other interactive dynamics systems.

• Journal of the Korean Arthroscopy Society
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• v.8 no.2
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• pp.115-118
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• 2004

Purpose: The purpose of this study is to measure the internal and external rotation of shoulder and compare with normal volunteer and patients diagnosed as SLAP lesion. Materials and Methods: Thirty-eight cases (group 1) who had SLAP lesions at shoulder arthroscopy and fourty young volunteers(group 2) were analyzed retrogradely with medical record, intra-operative arthroscopic photo & video for SLAP lesions and the ROM of shoulder Under the interscalene anesthesia, the range of motion of internal rotation and external rotation were measured on flxed scapula and 90 degree abduction of shoulder, and the same method for group 2. We analyzed the results with two sample T-test and Wisconsin signed ranks test. Results: There was a significant difference between group 1 and group 2 for the ROM of shoulder. (IR; p<0.001,ER; p<0.001).For the group 1, internal and external rotation with the arm abducted 90 averaged 50 and 64 degrees and for the group 2, internal and external rotation averaged 77 and 90 degrees with significant difference(IR; p<0.001,ER; p<0.001).Conclusion: The range of motion of shoulder, especially internal and external rotation significantly decreased in SLAP lesions. Our results suggest that a limited rotational motion of shoulder closely related with SLAP lesion.

• Korean Journal of Remote Sensing
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• v.24 no.2
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• pp.141-152
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• 2008

The 3D building modeling is one of crucial components in constructing 3D geospatial information. The existing methods for 3D building modeling depend mainly on manual photogrammetric processes, which indeed take great amount of time and efforts. In recent years, many researches on 3D building modeling using aerial LiDAR data have been actively performed to aim at overcoming the limitations of existing 3D building modeling methods. Either techniques with interpolated grid data or data fusion with digital map and images have been investigated in most of existing researches on 3D building modeling with aerial LiDAR data. The paper proposed a method of 3D building modeling with LiDAR data only. Firstly, octree-based segmentation is applied recursively to LiDAR data classified as buildings in 3D space until there are no more LiDAR points to be segmented. Once octree-based segmentation is completed, each segmented patch is thereafter merged together based on its geometric spatial characteristics. Secondly, building model components are created with merged patches. Finally, a 3D building model is generated and composed with building model components. The experimental results with real LiDAR data showed that the proposed method was capable of modeling various types of 3D buildings.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.2
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• pp.160-167
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• 2021

The purpose of this study was to investigate the prevalence and characteristics of pre-eruptive intracoronal radiolucencies (PEIR) from panoramic radiographs in Korean children and adolescents. This study examined panoramic radiographs of 3,000 patients aged between 5 and 14 years old who visited ten dental hospitals in Korea. The age and gender of the patients, the tooth type, the number of intracoronal radiolucent lesions, and the location and size of the lesions were recorded. The overall prevalence of patients with PEIR was 2.5%. The difference in the presence of PEIR between both genders was not significant. Within each tooth type, the mandibular first molar showed highest prevalence of PEIR (29.6%). The central part of the crown was the most frequently observed location of PEIR (56.8%). The size of the PEIR lesions was mostly limited to less than one-third of the thickness of coronal dentin.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.1
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• pp.31-41
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• 2021

The aim of this retrospective study was to evaluate the correlation between the midpalatal suture maturation and skeletal maturation in growing children aged 7 - 15 years and predict the maturational stages of the midpalatal suture corresponding to skeletal maturity assessed by the skeletal maturation indicators (SMI) and middle phalanx of the third finger (MP3) stages. The group of this retrospective study was consisted of randomly selected 132 male and 135 female in age from 7 - 15 years. The maturation of the midpalatal suture was evaluated by using images from cone-beam computed tomography (CBCT) while the skeletal age was assessed by hand-wrist radiography. CBCT images and hand-wrist radiographs used in this study were obtained from all subjects for orthodontic diagnosis before orthodontic treatment. The maturational stages of the midpalatal suture showed strong correlations with both SMI and MP3 stages. The correlation between the midpalatal suture maturation and SMI (Spearman's correlation coefficient, ϒ_S = 0.905, p < 0.05) was slightly greater than that of MP3 stages (ϒ_S = 0.830, p < 0.05). There was a positive significant correlation between the midpalatal suture maturation and chronological age (ϒ_S = 0.868,p < 0.05). CBCT for evaluation of the midpalatal suture maturational stages may be unnecessary in every pediatric patients because SMI and MP3 stages were both replaceable useful methods for assessing maturation of the midpalatal suture before orthopedic treatment. In this retrospective study, the diagnostic reliability of the SMI method for estimating midpalatal suture maturation showed better reliability than the MP3 method.

• Cross-Cultural Studies
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• v.49
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• pp.59-93
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• 2017

This paper provides an in-depth examination of the relationship between cinema and Giorgio Agamben's aesthetics and philosophy. Intersecting Agamben's key concepts including gesture, mediality, biopolitics, historicity, and profanation with historical and aesthetic dimensions of cinema, I argue for his ambivalent view on cinema and visual media. On the one hand, Agamben linked cinema and visual media to his discussion on biopolitics and spectacle as he considered them as apparatus for capturing and controlling gestures. On the other hand, he also argued that cinema could restore the image with capacity to preserve and recuperate gestures based on his consideration of montage as cinema's key aesthetic and technical component (an operation of profanation) and his Benjaminian thought on the ways in which montage suspended linear flow of images and activated an alternative memory of them. Drawing on history of cinema and optical devices in the 19th and early 20th centuries as well as examples of found footages of filmmaking predicated upon stoppage and repetition of images, I argue that Agamben's concept of potentialities can be extended into his thought on cinema and visual media apparatuses in general.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.323-328
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• 2019

In order to construct 3D geospatial information about the terrain, current measurement using a total station, remote sensing, GNSS(Global Navigation Satellite System) have been used. However, ground survey and GNSS survey have time and economic disadvantages because they have to be surveyed directly in the field. In case of using aerial photographs and satellite images, these methods have the disadvantage that it is difficult to obtain the three-dimensional shape of the terrain. The terrestrial LiDAR can acquire 3D information of X, Y, Z coordinate and shape obtained by scanning innumerable laser pulses at densely spaced intervals on the surface of the object to be observed at high density, and the processing can also be automated. In this study, terrestrial LiDAR was used to analyze slope displacement. Study area slopes were selected and data were acquired using LiDAR in 2016 and 2017. Data processing has been used to generate slope cross section and slope data, and the overlay analysis of the generated data identifies slope displacements within 0.1 m and suggests the possibility of using slope LiDAR on land to manage slopes. If periodic data acquisition and analysis is performed in the future, the method using the terrestrial lidar will contribute to effective risk slope management.

• Journal of Digital Convergence
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• v.17 no.11
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• pp.21-27
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• 2019

The study empirically analyzed the effects of content attitudes and recall on digital signage advertising appeal (information appeal vs. image appeal) and interactivity level (low vs. high). As a result, first, it was found that a moderately low level of interactivity had a positive effect on content attitudes and recall than when the level of digital signage was extremely high. In addition, at moderately low levels of interactivity, information appeals had higher content attitudes and recalls than image appeals. Second, the content of image appeal has a positive effect on attitude when the digital signage level of interactivity is high, and the image recall ad and information appeal ad have negative effects on recall. Third, the low level of interactivity of digital signage has a positive effect on the content attitude and recall of information appeal. With the advent of digital media in recent years, concerns about how to construct the level of interactivity and information content on a strategic level are increasing in practice. The results of this study are expected to suggest the direction of the strategic grounds for this.

• Journal of Digital Convergence
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• v.19 no.2
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• pp.245-251
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• 2021

As the trend of steadily increasing the number of single or double household, there is a growing demand to see who is the outsider visiting the home during the free time. Various models of face recognition technology have been proposed through many studies, and Harr Cascade of OpenCV and Hog of Dlib are representative open source models. Among the two modes, Dlib's Hog has strengths in front of the indoor and at a limited distance, which is the focus of this study. In this paper, a face recognition visitor access system based on Dlib was designed and implemented. The whole system consists of a front module, a server module, and a mobile module, and in detail, it includes face registration, face recognition, real-time visitor verification and remote control, and video storage functions. The Precision, Specificity, and Accuracy according to the change of the distance threshold value were calculated using the error matrix with the photos published on the Internet, and compared with the results of previous studies. As a result of the experiment, it was confirmed that the implemented system was operating normally, and the result was confirmed to be similar to that reported by Dlib.