• Journal of Institute of Control, Robotics and Systems
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• v.16 no.7
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• pp.695-702
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• 2010

This paper presents an image alignment algorithm for application of AOI (Automatic Optical Inspection) based on SIFT. Since the correspondences result using SIFT descriptor have many wrong points for aligning, this paper modified and classified those points by five measures called the CCFMR (Cascade Classifier for False Matching Reduction) After reduced the false matching, rotation and translation are estimated by point selection method. Experimental results show that the proposed method has fewer fail matching in comparison to commercial software MIL 8.0, and specially, less than twice with the well-controlled environment’s data sets (such as AOI system). The rotation and translation accuracy is robust than MIL in the noise data sets, but the errors are higher than in a rotation variation data sets although that also meaningful result in the practical system. In addition to, the computational time consumed by the proposed method is four times shorter than that by MIL which increases linearly according to noise.

• The Journal of the Korea Contents Association
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• v.20 no.2
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• pp.581-593
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• 2020

The purpose of this study was to examine the eye-fixation times on different parts of a student avatar and the virtual presence with two scenarios in the virtual reality-based teaching simulation. This study was to identify user attention while he or she is interacting with a student avatar. By examining where a user is gazing during a conversation with the avatar, we have a better understanding of non-verbal communication. For this study, forty-five college students (21 females and 24 males) participated in the experiment. They had a conversation with a student avatar in a virtual reality-based teaching simulation. The participants had verbal interactions with the student avatar with two scenarios. While they were having a conversation with the virtual character in the teaching simulation, their eye-movements were collected through a head-mounted display with an eye-tracking function embedded. The results revealed that there were significant differences in eye-fixation times. Participants gazed a longer time on facial expression than any other area. The fixation time on the facial expression was more prolonged than on gestures (F=3.75, p<.05). However, the virtual presence was not significantly different in two scenario levels. This result suggested that users focus on the face more than the gesture when they emotionally interact with the virtual character.

• Korean Journal of Remote Sensing
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• v.37 no.6_3
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• pp.2027-2034
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• 2021

Using multi-temporal KOMPSAT-3/3A high-resolution satellite images, the Normalized Difference Vegetation Index (NDVI) for the area around the Fukushima daiichi nuclear power plant was determined, and the pattern of vegetation changes was analyzed. To calculate the NDVI, surface reflectance from the KOMPSAT-3/3A satellite image was used. Satellite images from four years were used, and the zones where the images overlap was designated as the area of interest (AOI) for the study, and by setting a profile passing through highly vegetated area as a data analysis method, the changes by year were examined. In addition, random points were extracted within the AOI and displayed as a box plot to quantitatively indicate change of NDVI distribution pattern. The main results of this study showed that the NDVI in 2014 was low within AOI in the vicinity of the nuclear power plant, but vegetated area continued to expand until 2021. These results were also confirmed in the change monitoring results shown in a profile or box plot. In disaster areas where access is restricted, such as the Fukushima nuclear power plant area, where it is difficult to collect field data, obtaining land cover classification products with high accuracy using satellite images is challenging, so it is appropriate to analyze them using primary outputs such as vegetation indices obtained from high-resolution satellite imagery. It is necessary to establish an international cooperation system for jointly utilizing satellite images. Meanwhile, to periodically monitor environmental changes in neighboring countries that may affect the Korean peninsula, it is necessary to establish utilization models and systems using high-resolution satellite images.

• The Journal of the Korea Contents Association
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• v.19 no.6
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• pp.214-221
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• 2019

Visual perception information acquired through human eyes contains much information on how to view visual stimuli using eye tracking technology, it is possible to acquire and analyze consumer visual information as quantitative data. These measurements can be used to measure emotions that customers feel unconsciously, and they can be directly collected by numerically quantifying the character's search response through eye tracking. In this study, we traced the character's area of interest (AOI) and found that the average of fixation duration, count, average of visit duration, count, and finally the time to first fixation was analyzed. As a result of analysis, it was found that there were many cognitive processing processes on the face than the character's body, and the visual attention was high. The visual attention of attraction factor has also been able to verify that attraction is being presented as an important factor in determining preferences for characters. Based on the results of this study, further studies of more characters will be conducted and quantitative interpretation methods can be used as basic data for character development and factors to be considered in determining character design.

• Journal of Oral Medicine and Pain
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• v.11 no.1
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• pp.57-66
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• 1986

A study of occlusal relationship and TMJ dysfunction, parafunctional relationship and TMJ dysfunction using PRI was investigated in 23 dental students without history of being treated, ranging from 19 to 24 years old. The author used Denar Pantronic and D5-A articulator to study above. The obtained results were as follows : 1. Distribution of PRI in experimental subjects was as follows. None 13%, Slight 43%, Moderate 40%, Severe 4% Prevalance of TMJ Dysfunction was 87% 2. PRI scores of occlusal group Aoi (less than 5 in Helkimo occlusion/articulation index) was $11.72\pm2.32$ , those of occlusal group Boi (more than 5 in Helkimo occlusion/articulation index) 23.0 $\pm$ 8.06. There was a significant difference between group Aoi and group Boi(P<0.01) 3. PRI scores of occlusal group Ald (no eccentric interference, less than 0.5mm in lateral shift of slide in centric) was 12.0 $\pm$ 2.49, those of occlusal group Bld(no eccentric interference, less than 0.5mm in lateral shift of slide in centric) 24.5$\pm$5.33 There was a significant difference between group Ald and group Bld(P<0.05) 4. Prevalance of parafunction subjects(%) was 65.2%. 5. PRI scores of parafunction group was 21.6 $\pm$ 9.48, those of nonparafunctional group 18.7 $\pm$ 9.06. There was not significant difference between parafunctional group and nonparafunctional group(P>0.1)

• Journal of Korea Multimedia Society
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• v.7 no.3
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• pp.388-398
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• 2004

This paper focuses on the reduction method of message traffic occurred when multiple participants collaborate in the distributed virtual environment. It is referred to as filtering method of update message to minimize data traffic exchanged in the virtual environment, and it is the essential process to improve the scalability of the virtual environment. Spatial partitioning method, a popular filtering technique, divides the whole environment into smaller sub-parts in order to make it small the regions to be maintained consistently. However, it is less flexible and adaptable because the information of area of interest must be configured before simulation. In this paper, the concept of dynamic area of interest is proposed, which is highly adaptable by applying dynamic environmental elements to AOI management. It uses multiple layering and multiple consistency algorithms for dynamic management, and makes it possible to consume system resource efficiently. For performance evaluation, experiments are performed with virtual avatars, measuring message traffic. Finally, the proposed model could be applied to the AOI management systems which accommodate massive users like MMORPG, or virtual communities.

• Journal of Environmental Science International
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• v.21 no.12
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• pp.1425-1433
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• 2012

Water temperature in the eastern part of the Yellow Sea (EYS) during winter (JFM) and summer (JJA) from 1964 to 2009 and Siberian High Pressure Index (SHI) and Arctic Oscillation index (AOI) during winter (JFM) from 1950 to 2011 were used to analyze long-term variation in oceanic and atmospheric conditions and relationship between winter and summer bottom water temperature. Winter water temperature at 0, 30 and 50 m had fluctuated highly till the late of 1980s, but after this it was relatively stable. The long-term trends in winter water temperature at both depths were separated with cold regime and warm regime on the basis of the late 1980s. Winter water temperature at 0m and 50m during warm regime increased about $0.9^{\circ}C$ and $1.1^{\circ}C$ respectively compared to that during cold regime. Fluctuation pattern in winter water temperature matched well with SHI and AOI The SHI had negative correlation with water temperature at 0 m (r=-0.51) and 50 m (r=-0.58). On the other hand, the AO had positive correlation with Winter water temperature at 0 m (r=0.34) and 50 m (r=0.45). Cyclic fluctuation pattern of winter water temperature had a relation with SHI and AO, in particular two to six-year periodicity were dominant from the early of the 1970s to the early of the 1980s. Before the late of 1980s, change pattern in winter water temperature at 0 and 50 m was similar with that in the bottom water temperature during summer, but after this, relationship between two variables was low.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.2
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• pp.453-459
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• 2017

Users tend to check in and post their statuses in location-based social networks (LBSNs) to describe that their interests are related to a point-of-interest (POI). While previous studies on discovering area-of-interests (AOIs) were conducted mostly on the basis of density-based clustering methods with the collection of geo-tagged photos from LBSNs, we focus on estimating a POI boundary, which corresponds to only one cluster containing its POI center. Using geo-tagged tweets recorded from Twitter users, this paper introduces a density-based low-complexity two-phase method to estimate a POI boundary by finding a suitable radius reachable from the POI center. We estimate a boundary of the POI as the convex hull of selected geo-tags through our two-phase density-based estimation, where each phase proceeds with different sizes of radius increment. It is shown that our method outperforms the conventional density-based clustering method in terms of computational complexity.

• Education of Primary School Mathematics
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• v.20 no.4
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• pp.305-319
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• 2017

In the process of finding the triangle height, 26 students in the 6th grade were surveyed to understand the students' triangle height through the eye movement data and to investigate the cognitive load of the students. As a result, the correctness rate of the pre-test was significantly increased in the post-test, and the frequency and retention of gaze data were smaller in the post-test than in the AOI of each question. The Participants's subjective cognitive load indicated that it was more difficult to understand the concept of rotated triangles compared with upright triangles that were parallel to the ground. More frequent and more retentions in the eye-tracking data were detected in the right triangles and acute triangles by rotating configuration. Eye movement data show that eye tracking technology can provide an objective measure of students' cognitive load for feedback on instructional design.

• Journal of Internet Computing and Services
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• v.7 no.6
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• pp.51-62
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• 2006

The load of this kind of gores, which is heavier than that of any other precedent, and on enormous seamless virtual world characterize the MMORPG(Massively Multiplayer Online Role-Playing Game) genres. In this seamless environment, gamers can usually accept a set of independent spaces, which is being held by independent game servers, os a single big virtual world. Despite the efforts of some developers, gamers are suffered from huge message traffic which comes from the interaction between client and server and the interaction between fold sowers. In this paper, new gore server architecture using MigAgent is proposed which tries to reduce message traffic. Usually, message traffic reaches the climax when a PC(Player Character) is moving to other field server. MigAgent, designed in this thesis, tries to manage this kind of PCs and to ploy o role of user's agent to prepare for the unexpected situation. Improvement of this system is shown by the analysis of the effect of the size ratio of AOI (Area of Interest) and AC (Adjacent Cell).