• The korean journal of orthodontics
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• v.36 no.4
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• pp.263-274
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• 2006

Objective: The purpose of this study was to evaluate clinical and microbiological changes in periodontal tissue around the banded molars after debanding. Methods: This study included 17 young adult patients treated with fixed orthodontic appliances including bands on the last molars more than 1 years. Probing depth and bleeding frequency were measured and plaque samples were collected from the last banded molars in all quadrants of each patient. All the data were collected immediately after debanding and 4 weeks after debanding. Results: Using polymerase chain reaction based on 16S rDNA, the presence of Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola was detected. After debanding, probing depth, bleeding frequency, and prevalance of periodontopathogens were reduced. Probing depth and bleeding frequency were most decreased in the buccal site of the mandibular left molar and were least decreased in the lingual site of the maxillary right molar. Conclusion: The results of this study indicated that proper management of oral hygiene after debanding can recuperate unfavorable periodontal condition caused by orthodontic treatment.

• Clean Technology
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• v.11 no.2
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• pp.91-104
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• 2005

We studied more effective Environmental R&D management system which can be used in the budget allocation of the national R&D budget by the newly opened governmental administration system of science and technology. As a first step, we surveyed classification systems for the environmental technology which can be applied to the analysis of the national R&D budget. Each organization, either inland and oversea, has its own classification system for the environmental technology. However, we found that each systems can lead different results. It would be beneficial if an efficient standard classification system could be generated. The new system classified the environmental technology by the environmental management area(media) like most present systems rather than by the technical characteristics. The new system included all the areas of the environmental management and maintained consistent principles. The new system would help efficient management of the national R&D of the environment technology, if the national standard classification can be changed by the new system. To the researchers and professionals the new system will help them noticing the status of the environmental R&D and avoiding duplicate research, so that they can do research more efficiently and can achieve maximized results.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.6
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• pp.10-18
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• 2010

This paper proposes an image stabilization algorithm for close watching UAV(Unmanned Aerial Vehicle) using motion separation and stabilization mode. The motion of UAV is composed of its actual navigating motion and unwanted vibrating motion so that image sequences obtained from UAV are shaken randomly. In order to stabilize these images we separate the vibrating motion component from UAV motion and remove the effect caused by it from image sequences. In the proposed algorithm the motion and global intensity change of two consecutive images are modeled with 6 motion parameters and 2 intensity change parameters respectively. These modeled parameters are estimated by non-linear least square method based on Gauss-Newton algorithm. The vibrating motion component is separated from the estimated motion using IIR filtering and the geometric deformation caused by it is removed from image sequences. In order to apply the proposed method to real aerial image sequences with many abrupt changes of camera view, we proposed a stabilizing method using two different modes named as stabilizing and non-stabilizing mode. Experimental results show that the accuracy of motion estimation is 99% and the efficiency of removing the vibrating motion component is 90%. We apply the proposed method to real aerial image sequences and verified its stabilizing performance.

• Journal of the Korean Arthroscopy Society
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• v.12 no.2
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• pp.98-101
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• 2008

Purpose: To evaluate the results of arthroscopic removal of calcific deposit depending on the phase-dependent progress of recalcitrant calcific tendinitis of the shoulder. Materials and Methods: From January, 2003 to September, 2007, arthroscopic treatment of calcific tendinitis of the shoulder joint, especially supraspinatus was performed in 27 consecutive patients who had had typical symptoms and failed with the conservative treatment and all patients could be followed up at least 6 months. We evaluated the visual analogue scale at preoperative, postoperative 2 weeks and 6 months. The results were compared according to the arthroscopic findings. Results: 11 cases were chalky calcium deposit of arthroscopic finding and 16 cases were toothpaste-like appearance. The VAS was 8.0 of the group with chalky deposit and 8.3 with toothpaste-like deposit preoperatively, which was not significantly different. However, at postoperative 2 weeks, it was 6.7 with chalky deposit and 2.7 with toothpaste-like, which is significantly different. At postoperative 6 months, the symptoms of all patients were resolved. Conclusion: Resorptive phase is well respond to surgical excision at early postoperative evaluation. The phase of calcific tendinitis is one of important factors for rapid resolution of the shoulder pain and functional improvement after arthroscopic treatment.

• Industry Promotion Research
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• v.5 no.3
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• pp.61-71
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• 2020

The purpose of this paper is to reaffirm the logical framework of the saju analysis method by recreating the saju model of old-law to study and organize the theories of frame in old-law Myeongri, and then by organizing and comparing the logic structure of the saju analysis method of new-law and old-law. Some believe that Myeongri Theory first appeared in the world in the Warring States Period when they were active with Gwigokja and Naknokja as origin, while others believe that it was origin that "Okjokyeong" was written by Kwak-Bak of Eastern Jin after a while. Since then, Myeongri Theory, which had been organized by Won-Cheongang and Yi-Heojung, has undergone a major transformation since reaching the Song Dynasty Seo-Japyeong. Based on this point, the Myeongri Theory of the previous generation is called the Old-law, and the subsequent theory is called the New-law. The changes in the logic structure of the old-law and the new-law leave a big difference and disconnect between those. But comparative studies have confirmed that the philosophy and logic structure due to natural laws that have not changed much such as the symbolic system of nature called Yinyang & five elements and Cheongan-jiji, the idea of a heavenly response projected in the Three Wonders of heaven, earth and human, and the concept of generation and time in the position of year-month-day-time.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.15-23
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• 2019

The sprayable waterproofing membrane is a recently introduced material in the civil engineering field, and is a material that sprays and attaches a single phase or two phase powder or liquid material to a surface to be covered using a pump and nozzle. Although the material properties are gradually reported through researches, there is a lack of studies on long-term performance compared to concrete materials used with the membranes. In this study, the long-term performance of materials was estimated using the Arrhenius equation. The temperature conditions used in this study were 65℃, 80℃ and 95℃, and the temperature was maintained with the membrane attached to the concrete block for long-term behavior. Then the membranes were tested for tensile strength and adhesion strength in the order of 30, 90, 150, 200, and 300 days. The long-term performance of the material was determined from a long-term perspective by estimating the activation energy by the Arrhenius equation. Consequently, the time to reach 50% of the performance standard could be estimated by long-term test.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.1
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• pp.25-33
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• 2020

A drought event is characterized by duration, severity and affected area. In general, after calculating a drought index using hydro-meteorological time series at a station, a drought event is defined based on the run theory to identify the beginning and end time. However, this one-dimensional analysis has limitations for analyzing the spatio-temporal occurrence characteristics and movement paths of drought. Therefore, this study is to define a three-dimensional drought event using a simple clustering algorithm and to develop a drought map that can be used to understand the drought severity according to the spatio-temporal expansion of drought. As a result, compared with the two-dimensional monitoring information to show spatial distribution of drought index, a proposed drought map is able to show three-dimensional drought characteristics inclusing drought duration, spatial cumulative severity, and centroid of drought. The analysis of drought map indicated that there was a drought event which had the affected area less than 10 % while on occations while there were 11 drought events (44 %) which had the affected area more a than 90 % of the total area. This means that it is important to understand the relationship between spatial variation of drought affected area and severity corresponding to various drought durations. The development of drought map based on three-dimensional drought analysis is useful to analyze the spatio-temporal occurrence characteristics and propagation patterns of regional drought which can be utilized in developing mitigation measures for future extreme droughts.

• Journal of the Korea Society for Simulation
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• v.29 no.1
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• pp.57-69
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• 2020

Many researchers have recommended that DBR scheduling would be an efficient method to maintain the balance of their workload among many processes in the general flow shop. However, as product variety has increased in recent years, the process has become more complex and requires the re-entrance of raw materials and work in process. The re-entrant line has known for the complex manufacturing process that raw materials are repeatedly processed on the same machine. This study reviews the applicability of DBR against the re-entrant manufacturing line due to the distinguishing characteristics and the higher complexity caused by multiple visits of a job into the identical process. In order to apply the DBR method to the re-entrant process, the main idea is to reconstruct re-entrant process into a virtual flow process(loop) that has a single bottleneck. This study discusses the following two questions. First, DBR is also superior to traditional scheduling methods against re-entrant manufacturing line. And how we structure and detect the system bottleneck (or sub-bottleneck) through drum-buffer-rope concepts. To answer the above questions, we experimented and analyzed the effects of the applicability of DBR under the general re-entrant process model(TRC, Technology Research Center). As a result, we have identified a balance between loops for cycle time and work in process.

• Journal of Digital Convergence
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• v.14 no.10
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• pp.521-534
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• 2016

This study examined the neurophysiological mechanisms of exercise deprivation by investigating differences in emotion changes and EEG prefrontal asymmetry in relation with exercise. Twenty male undergraduate university students in the 23-27 age range, amateur marathon runners, were selected as the participants (n=20) and divided into one of two experimental conditions at random: (1) exercise deprivation group (n=10), and (2) non-exercise deprivation group (n=10). PANAS-X measurement and EEG measurement from F3 and F4 scalp sites were performed at pre-test, 3 days after exercise deprivation, and 5 days after exercise deprivation. Results revealed that participants of EDG significantly decreased a positive effect after exercise deprivation on EEG and self-reported measures, and showed an increased negative effect after exercise deprivation on self-reported measures. In contrast, participants of NEDG significantly increased positive feelings after exercise and showed a decreased negative effect after exercise on EEG and self-reported measures. Our results showed that exercise deprivation increasing negative emotion after exercise deprivation. The findings of this study suggest that EEG frontal brain asymmetry can be used as diagnosing method for exercise deprivation.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.5
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• pp.345-352
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• 2016

As aircrafts are being operated at high altitude, wing structures experience various fatigue loadings under cryogenic environments. As a result, fatigue damage such as a crack could be develop that could eventually lead to a catastrophic failure. For this reason, fatigue damage monitoring is an important process to ensure efficient maintenance and safety of structures. To implement damage detection in real-world flight environments, a special cooling chamber was built. Inside the chamber, the temperature was maintained at the cryogenic temperature, and harmonic fatigue loading was given to a wing structure. In this study, piezoelectric active-sensing based guided waves were used to detect the fatigue damage. In particular, a beamforming technique was applied to efficiently measure the scattering wave caused by the fatigue damage. The system was used for detection, growth monitoring, and localization of a fatigue crack. In addition, a sensor diagnostic process was also applied to ensure the proper operation of piezoelectric sensors. Several experiments were implemented and the results of the experiments demonstrated that this process could efficiently detect damage in such an extreme environment.