• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.9
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• pp.786-791
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• 2012

This paper presents a depth boundary sharpening method for improved view synthesis in 3D video. In depth coding, distortion occurs around object boundaries, degrading the quality of synthesized images. In order to encounter this problem, the proposed method estimates an edge map for each frame to filter only the boundary regions. In particular, a window-based filter is employed to choose the most reliable pixel as the replacement considering three factors: frequency, similarity and closeness. The proposed method was implemented as post-processing of the deblocking filter in JMVC 8.3.Compared to the conventional methods, the proposed method generated 0.49 dB PSNR increase and 16.58% bitrate decrease on average. The improved portions were subjectively confirmed as well.

• Journal of Information Technology Services
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• v.15 no.4
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• pp.97-109
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• 2016

The rapid deployment of millions of mobile sensors and smart devices has resulted in high demand for opportunistic encounter-based networking. For the cooperative video surveillance of dashboard cameras in nearby vehicles, a fast and energy-efficient asynchronous neighbor discovery protocol is indispensable because a dashboard camera is an energy-hungry device after the vehicle's engine has turned off. In the existing asynchronous neighbor discovery protocols, all nodes always try to discover all neighbors. However, a dashboard camera needs to discover nearby dashboard cameras when an event is detected. In this paper, we propose a fast and energy-efficient asynchronous neighbor discovery protocol, which enables nodes : 1) to have different roles in neighbor discovery, 2) to discover neighbors within a search range, and 3) to report promptly the exact discovery result. The proposed protocol has two modes: periodic wake-up mode and active discovery mode. A node begins with the periodic wake-up mode to be discovered by other nodes, switches to the active discovery mode on receiving a neighbor discovery request, and returns to the periodic wake-up mode when the active discovery mode finishes. In the periodic wake-up mode, a node wakes up at multiples of number ${\alpha}$, where ${\alpha}$ is determined by the node's remaining battery power. In the active discovery mode, a node wakes up for consecutive ${\gamma}$ slots. Then, the node operating in the active discovery mode can discover all neighbors waking up at multiples of ${\beta}$ for ${\beta}{\leq}{\gamma}$ within ${\gamma}$ time slots. Since the proposed protocol assigns one half of the duty cycle to each mode, it consumes equal to or less energy than the existing protocols. A performance comparison shows that the proposed protocol outperforms the existing protocols in terms of discovery latency and energy consumption, where the frequency of neighbor discovery requests by car accidents is not constantly high.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.6
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• pp.405-413
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• 2019

Deployable structures are widely used for space mission because of their advantages in storage and transportation coming from its transformability of configuration. The space structures should be designed with high stiffness to withstand the various types of disturbance that they encounter during operation. Especially for the deployable structures, the internal forces loaded on the component or the stiffness at its deployed configuration should be analyzed since they usually consist of the thin and light structures. In this paper, a dynamic model of the scissors structure is established and its deployment behavior is analyzed, especially focusing on the deployment speed and the internal force on each joint. In addition, modal analysis is carried out for the 1-stage and 2-stage scissors structures in order to analyze the stiffness of the scissors structure based on its deployed configuration. The fundamental mode shapes and natural frequencies are analyzed and discussed.

• Korean Journal of Community Nutrition
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• v.26 no.1
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• pp.1-11
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• 2021

Objectives: This study was conducted to assess the eating behavior, growth, and dietary practices of children aged 3~5 years living in the Seoul and Gyeonggi Provinces. Methods: Self-administered questionnaires were completed by 237 mothers of preschool children between April and June 2018. Z-scores for weight-for-age, height-for-age, and BMI-for-age were calculated to determine the children's growth status. Dietary practices were evaluated using the nutrition quotient for Korean preschoolers (NQ-P). Results: In our study, 29.5% of children were in the eating-small-amounts group, 46.8% of children were in the neophobic behavior group, and 61.2% of children were in the refusal-of-specific food group. Specific foods found to have a high frequency of rejection are listed in descending order as follows: shellfish, soy, mushroom, shrimp, vegetables, milk, eggs, yogurt, seaweed, meat, fruits, and fish. The eating-small-amounts group had lower Z-scores for weight-for-age, height-for-age, and BMI-for-age than the non-picky eaters' group. Compared to the non-picky eaters' group, the eating-small-amounts group of picky eaters had lower scores on the moderation and environment items of the NQ-P, the neophobic behavior group had lower scores on the balance and environment items of the NQ-P, and the refusal-of-specific food group had lower scores on the balance, moderation, and environment items of the NQ-P. Conclusions: Children classified with picky eating behavior had lower growth and development, lower diet diversity, less balanced food intake, and had greater difficulty in abstaining from eating unhealthy foods than non-picky eaters. Therefore, a lot of patience and intensive efforts are needed to encourage children to encounter, experience, and accept unfamiliar food. It is more effective to provide eating behavior guidance by gently encouraging children, than by being strict and forceful. Besides, since the eating behavior of children is influenced maximally by the dietary lifestyle at their homes, it is important to ensure that a healthy dietary lifestyle is maintained at home.

• Journal of Korean Public Health Nursing
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• v.12 no.2
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• pp.172-184
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• 1998

This study was to examine the characteristics of aggressive behaviour of dementia patients. It was based on the observation of the patients in a facility for dementia patients. Observation continued for two days from 9a.m. to 5p.m .. aggressive behavior was recorded using the instrument of Ryden. The result of this study is as follows. 1. appearance rate of aggressive behaviour During two days $74\%$ of the patients did aggressive behaviour(first day-$41.8\%$. second day-$62.8\%$). The average aggressive behaviour per person was 1.65. 2. types of aggressive behaviour Aggressive behaviour was the most frequent in verbal domain(157 case; $52.5\%$). Physical domain was the second$(136case;\;45.5\%)$, and sexual domain was the last$(6 case;\;2.0\%)$. More concretely, abusive/vulgar language$(74case;\;24.7\%)$ was more than anything else. Aggressive language$(65case;\;21.7\%)$, pushing$(39case;\;13.0\%)$, intimidating posture$(21case;\;7.0\%)$. slapping $(18case;\; 6.0\%)$ followed it. 3. correlation to other factors such as sex. age etc. The average aggressive behaviour of female(2.07) was higher than that of male(1.23) (p=.05). Age also had meaningful correlation to the frequency of aggressive behaviour(p=.04). All the other factors-the period of living in facility, the seriousness of dementia. movements in daily life. CAPE, emotional state. the extent of trouble in cognition- have nothing to do with the frequency of aggressive behaviour. 4. the time, place and the target of aggressive behavior Aggressive behaviour appeared more frequently in the afternoon $(138case;\;46.4\%)$ than in the morning or at lunch time. The patient's room ranked the first in the list of places where aggressive behaviour took place $(162case;\; 54.5\%)$. Nursing personnel topped in the target of aggressive behaviour$(119case;\; 39.8\%)$. 5. the preceding causes of the aggressive behavior the most frequent preceding causes of the behavior was the stimulus of another residents $(133case, 44.4\%)$ and that of nsg personnel was few relatively$(65 cases,\; 21.7\%)$. 6. Nursing personnel used verbal reaction most frequently$(40 cases,\; 51\%)$ and in a behavioral reaction they used physical restraint $(12 cases,\; 17.1\%)$ most frequently. In the reactions of nsg personnel. the rate of undesired reaction was high$(41cases,\; 44.28\%)$. and in that of the attacked residents, the usual reaction was most frequent $(80cases,\; 65.0\%)$. In the future it is needed to investigate the characteristics of aggressive behavior of dementia patients, and based on this the method of intervention must be developed. Today the number of dementia patient increases so nurses must strive to encounter aggressive behavior more desirably.

• Ecology and Resilient Infrastructure
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• v.3 no.2
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• pp.117-125
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• 2016

Current cities encounter various types of water problems due to rapid urbanization and climate change. The increasing significance of urban water problems calls for the establishment of resilient alternatives to prevent and minimize social loss that results from these phenomena. As a background research for establishing resilient infrastructures for the mitigation of urban water problems, we evaluated the robustness of structural alternatives for urban flood as a representative case. Combining the robustness index (RI) and the cost index (CI), we suggested the robustness-cost index (RCI) as an indicator of the robustness of structural alternatives, and applied the index to assess the existing infrastructures and structural alternatives (i.e., sewer network expansion, additional storage tank construction, and green roof construction) at a site prone to floods located around Gangnam-station, Seoul, Korea. At a rainfall intensity frequency range of 2 to 20 years, the usage of a storage tank and a green roof showed relatively high RCI value, with a variation of an alternative showing greater RCI between the two depending on the size of design rainfall. For a rainfall intensity frequency of 30 years, installing a storage tank with some green roofing was the most resilient alternative based on the RCI value. We proposed strategies for establishing resilient infrastructures for the mitigation of urban floods by evaluating the robustness of existing infrastructures and selecting optimal structural alternatives with the consideration of scales of design disaster.

• Journal of Preventive Medicine and Public Health
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• v.30 no.2 s.57
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• pp.356-368
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• 1997

In effort to determine whether aircraft noise can have health effects such as hearing loss, hypertension and psychological stress, a total of 111 male professors and administrative officers working a college near a military airport in Korea(exposed group) and a total of 168 males and 112 females matched by age groups(control groups) were analyzed. Personal noise exposure and indoor and outdoor sound level of jet aircraft noise were measured at the exposed are3. And pure tone, air conduction test and measurement of blood pressure were given to the exposed(males) and matched control groups (males and females). BEPSI(Brief Encounter Psychological Instrument) and psychological response to aircraft noise were examined for the exposed group. The noise dosimetry results revealed time-weighted averages(TWAs) that ranged from 61 to 68 dBA. However the levels encountered during taking off jet airplanes reached 126 dBA for two half minutes time period. Th, audiometric, test showed that mean values of HTL(hearing threshold level) in exposed group at every frequency(500, 1,000, 2,000, 4,000, and 8,000 Hz were much lower than them of male and female control groups. And in old age groups, interaction of age and noise was observed at 8,000 Hz in both ears(p<0.05). Conclusively, aircraft noise does not appear to induce hearing loss directly in high frequency, but may decreased hearing threshold level by interaction of aging process and noise exposure. However, difference of mean values of exposed and control groups on blood pressure was not significantly. In psychological test, annoyance was the most severe psychological response to noise in exposed group, but mean value of BEPSI was not correlated with job duration in exposed group.

• Geophysics and Geophysical Exploration
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• v.5 no.4
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• pp.272-279
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• 2002

During field survey of ground penetrating radar or borehole radar, we often encounter some problems which could be solved easily by modifying structure of the system such as antenna length, shape or array. In addition, it is necessary that the user could easily modify configuration of the radar system na test various array of antennas in order to verify and confirm numerical modeling results concerning radar antennas. We have developed network-analyzer-based, stepped-frequency georadar system. This system had been comprised with coaxial cable to confirm possibility of the system, then we have upgraded the system to use optical cable that is composed of optical/electric transducers, electric/optical transducers, amp, pre-amp and antennas. The software for the aquisition of data has been developed to control the system automatically using PC with GPIB communication and to display the obtained data graphically. We have tested the system in field survey na the results have been compared with those of RAMAC/GPR system.

• Journal of The Korean Association For Science Education
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• v.41 no.1
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• pp.11-18
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• 2021

The purpose of this study is to analyze the questions generated by elementary school pre-service teachers when reading the teacher's guide for the refraction of light, and to analyze the difficulties in understanding the concept and in making instructional plans. A total of 592 meaningful questions were generated by 283 elementary school pre-service teachers after reading the teacher's guide of 'light and lens' unit in the 6th grade of the 2015 revised curriculum. Of these, 306 questions are for understanding the concept of physics and 286 are pedagogical questions. As a result of the analysis, in terms of understanding the concept of physics, the elementary school pre-service teachers encounter difficulties in understanding the concept of the 'cause' of the phenomenon suggested in the textbook, such as the cause of refraction, the reason for scattering light, and the cause of the image change depending on the focal length of the convex lens. In terms of instructional planning, it was followed by questions about how to explain concepts, questions about not being able to explain concepts to elementary school students and having to teach only phenomena, specific explanation methods for specific concepts, and experimental methods. Although the teacher's guide contains various explanations and supplementary materials to help teachers understand the concept, it can be seen that there are many elementary pre-service teachers who cannot answer questions about some concepts even after reading the guide. For concepts with a high frequency of questions, it is necessary to prepare a tutorial that is more understandable. In the instructional plan, there were many questions about teaching methods and experimental methods, so it is necessary to provide more examples and specific experimental methods for explaining concepts in the teacher's guide.

• The Korean Journal of Ecology
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• v.17 no.3
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• pp.299-310
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• 1994

Intraspecific clonal interactions have important influences on a population structure of the cellular slime mold (CSM). This study was to investigate whether or not evolutionary change in a population could be induced by clonal competition, and to elucidate how various clones in a population evolve in a homogeneous environment of laboratory culture. The characteristic clones of Polysphondylium pallidum which had different resource consumption rates (RCR) and mating types I and II were selected for study. Investigation was conducted for 4 experimental time interval $(T_0-T_4)$; one experimental time interval took almost 10-14 days from inoculation to havest of fruiting bodies. Two sets of 50 clones were cultured from 50 clones at To, and RCR variations of the population were compared between $(T_0\;and\;T_4)$ for each set of clones. Each clone of the CSM had a diverse resource consumption rate, or growth rate, in a homogeneous and limited Cerophyl agar plate despite the passage of 48-56 generations from the beginning of the experiment. Diverse clones with different growth rate could coexist in one site of the homogeneous agar plate as well as heterogeneous soil microenvironment. When there was high clonal diversity of RCR, a clone in a population had high chances to encounter other clones with resultant increased clonal competition. In one set, 26 of 37 clones of mating type I were changed to mating type Il for the 4 experimental time intervals, which indicated that the rate of competitive exclusion among clones during total experiment from $(T_0\;to\;T_4)$ was 0.703. In another set, 31 of 37 clones of mating type I were changed to mating type II , having the rate of competitive exclusion 0.838. The frequency of each of mat~ng types changed by 0.93-1.29% in each successive generation. The competitive exclusion among clones occurred by 1.26-1.75% when approximately $2.6{\times}10^8$ bacterial cells were provided as food and thereafter one generation of myxamoebae of CSM elapsed at room temperature. This finding implicated that in the vegetative state of P, pallidurn there was 1.26-1.75% probabil~ty of evolutionary change per generation changing from one clone to another clone.