• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.2
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• pp.81-91
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• 2002

Dental implant systems have shown many post-surgical problems and One of the most frequent problem is screw loosening. To reduce screw loosening, a number of methods have been tried and recently fundamental modification of fixture-abutment connection structure was developed and used the most frequently. Former implant system structure, such as Br${\aa}$nemark, had external hex with the height of 0.7 mm and later, fixture with external hex of 1.0 mm height and internal hex structure were developed. In addition, the method of morse taper application was introduced to reduce screw loosening. In this study, the level of screw loosening of each implant systems was compared based on the vibration loosening measurement of abutment screw of each implant systems. Analysis of measured value was performed using 3 kinds of methods, (i) Percentage of average of initial 3 times loosening-torque value(initial loosening value) to tightening-torque of 30 Ncm, (ii) Percentage of loosening-torque value after 200 N strength loaded(experimental value) to initial loosening value and (iii) Percentage of experimental value to 30 Ncm of tightening-torque. Each result of analyses shows the value of initial loosening, loosening by repetitive load and final loosening level. The results of this study were as follows. (1) Percentage of initial loosening value to tightening-torque was increased in order of 0.7 mm external hex, 1.0 mm external hex, internal hex and internal taper and all values between each groups showed statistical significance (p<0.05). (2) Percentage of experimental value to initial loosening value was increased in order of internal hex, 0.7 mm external hex, 1.0 mm external hex and internal taper. Value of internal taper showed significant difference with that of 0.7 mm external hex and internal hex (p<0.05). (3) Percentage of experimental value to tightening torque was increased in order of 0.7 mm external hex, 1.0 mm external hex, internal hex and internal taper. Values of all groups showed statistical significance (p<0.05) except between the groups of 1.0 mm external hex and internal hex. Based on those results, there was no significant difference of loosening-torque by repetitive loading except internal taper. It is supposed that implant system with high resistant capability against initial loosening could be recommended for clinical use. In addition, in case of single implant restoration, 1.0 mm external hex or internal hex could be recommended rather than 0.7 mm external hex, and the use of internal taper would be the most useful way to reduce screw loosening.

• Journal of Oral Medicine and Pain
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• v.38 no.3
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• pp.235-246
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• 2013

Age estimations by forensic odontology play a great role in personal identification. The purpose of this study was to analyze the characteristics of age estimation cases in Korea. Surveying clients who requested age estimation at the Department of Oral Medicine, Kyungpook National University Dental Hospital from March 2012 to March 2013. The results were as follows: 1. On gender distribution, females(57.14%) were more than males(42.86%). The elderly with 50's and over 60's were majorities(89.28%) of clients, and no clients were below 40's. Most of clients were equal to and lower than elementary school graduate(69.64%). 2. The most frequent reason for age discrepancy between registered age and alleged age was mistakes by family or relatives(80.36%). The purposes of age estimation were welfare(62.50%), social relationship problem(12.50%), to find right age(10.71%), and occupation(8.93%). 3. In order of route to visit at Department of Oral Medicine, they were via government office(48.21%), acquaintances(21.43%), mass media(14.29%), and clinic(10.71%). Clients had high degree of comprehension on age estimation with forensic odontology (scored 7.03 out of 10). The 2/3 of clients were satisfied with present fee for age estimation. 4. The percentage on the proximity of estimated age to alleged age was 69.81%. 4(11.43%) clients were approved on age correction by court.

• The Journal of Bigdata
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• v.4 no.2
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• pp.159-173
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• 2019

Last-Mile delivery optimization plays a key role in the urban supply chain operation, which is the most expensive and time-consuming and most complicated part of the whole delivery process. The urban consolidation center (UCC) is regarded as a significant asset for supporting customer demand in the last-mile delivery service. It is the key benefit of UCC to improve the load balance of vehicles and to reduce the total traveling distance by finding the better route with the well-organized multi-leg vehicle journey in the urban area. This paper presents the model using multiple scenario analysis integrated with mathematical optimization techniques using Geographic Information System (GIS). The model aims to find the best solution for the distribution network consisted of DC and UCC, which is applied to the case of Ulaanbaatar Mongolia. The proposed methodology integrates two sub-models, location-allocation model and vehicle routing problem. The multiple scenarios devised by selecting locations of UCC are compared considering the general performance and delivery patterns together. It has been adopted to make better decisions the quantitative metrics such as the economic value of capital cost, operating cost, and balance of using available resources. The result of this research may help the manager or public authorities who should design the distribution network for the last mile delivery service optimization using UCC within the urban area.

• Journal of Technologic Dentistry
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• v.38 no.1
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• pp.23-36
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• 2016

Purpose: The purpose of this study is to suggest direction for dental technicians and management of dental laboratories to contribute to the improvement of oral health of citizens with high-quality dental prosthesis by researching operational status and management satisfaction of dental laboratories. Methods: In order to investigate operational status and management satisfaction of dental laboratories, this study conducted a questionnaire survey by mailing questionnaires to heads of dental laboratories designated as clinical training workshops of Department of Dental Technology of G University and a total of 158 questionnaires were used for analysis. Results: As for gender, males were 142 persons (89.9%) and females were 16 persons (10.1%). For location of the laboratories, number of laboratories in metropolitan cities was 94 (59.5%) while small and that in mid-sized cities was 64 (40.5%). As for the satisfaction with job, those who have managed dental laboratories for 23-30 years ($1.92{\pm}77$), transact with 7-12 dental clinics ($1.70{\pm}75$), had monthly income of 4-8 million won ($1.74{\pm}.80$) and had 8-10 employees ($2.33{\pm}.68$) were the highest in their satisfaction. As for satisfaction with management, those who have managed their business for 15-20 years ($2.86{\pm}.52$), transact with more than 20 dental clinics ($2.00{\pm}.04$), had monthly income of less than 4 million won ($2.00{\pm}.85$) and had less than 3 employees ($2.00{\pm}.62$) were the highest in their satisfaction. As for monthly income, those with less than 2 million won were 24 persons (15.2%), 2-4 million were 64 persons (40.5%), 4-6 million were 40 (25.3%), 6-8 million were 14 (8.9%) and over 8 million won were 16 persons (10.2%). As for number of employees, those with less than 3 employees were 32perosns (20.3%), 4-7 were 82 (51.9%), 8-10 were 26 (16.5%) and more than 11 were 10 persons (6.3%). As for severance payment, 84 persons practiced it according to Labor Standard Act (53.2%) and 34 practice it to a proper degree (21.5%) while 20 did not practice it at all (12.7%) and 20 persons did not respond to the question (12.7%). Conclusion: Although dental laboratories have rapidly expanded in number from 473 in 1986 to 2,400 in 2015, dental technician circles are facing difficulty in their management due to fierce competition and low profitability. Therefore, in order to improve this problem, it is necessary to readjust prices for dental prosthesis to realistic ones.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.11 s.102
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• pp.1131-1137
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• 2005

An orthogonal frequency division multiplexing(OFDM) system has the problem of peak-to-average power ratio (PAPR) due to the overlapping phenomena of many sub-carriers. In order to improve the performance of PAPR, we propose in this paper a new genetic sub-block phase weighting(GA-SPW) using the SPW technique. Not only the selecting mapping(SLM) and the partial sequence(PTS) but also the previously proposed SPW becomes more effective as the number of sub-blocks and phase elements increases. However, all of them have limitation on the number of sub-blocks since the searching repetition increases exponentially as the number of sub-blocks increases. Therefore, in this research, a new GA SPW is proposed to reduce the amount of calculation by using Genetic algorithm(GA). In the proposed method, the number of calculations involved in the iterative phase searching yields to depend on the number of population and generation not on the number of sub-blocks and phase elements. The superiority of the proposed method is presented in the experimental results and analysis.

• Journal of the Korean Home Economics Association
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• v.11 no.1
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• pp.3-13
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• 1973

This article has an aim to study what kind of housing system our ancestors lived with during the Yi-Dynasty by analyzing the house-plan of upper-class society of that period since the house of lower-class was very insignificant as it has always been while the house of upper-class represented the period. With this study we can clearly see how we ought to go in the right direction toward the development of our Korean genuine housing by renovating and renewing those unreasonable points in our traditional housing system. It is firmly believed that we should-keep our own unique traditional lovely housing system for being destroyed by the whirl-wind of modernization and the demand of rationalism and efficiency-centered idea of the western mind. From this view point we think it is very urgent to see this matter correctly and find out the real way how we should do in order to keep our own good things for ourselves and make them preserved. This essay is divided into three parts as follows : 1. Thoughts on selecting the good housing area. 2. The aspect of housing reflected upon composing the house-plan. 3. The characteristic sentiments reflected upon the interior construction and decoration. We can find several characteristic points in the housing system of the Yi-Dynasty as follows : 1. In Korea, the thought of natural geography (Poongsu-seul), apart fro scientific view, which seems rather superstitious to us, modern young people, has been highly recommended by the people of our country from old days connected with the prosperity of our life. They also neglected about the social circumstances such as, market, transportation, and education, which are now considered as very important. They only put their concern on this natural environment which they called Poongsu. 2. In construction of house-plan, the house was not built for living with reasonable convenience, but for showing prestige of the upper-class people reflecting its social organization under the feudalism of the period. Furthermore, the most of the housework was done actually by those servants and maids of the house, and not the family themselves. The only concern for the upper-class people was to show off their authority, and so this sense of authority was revealed in the housing as well. 3. Both the outside appearance of the house and the interior decoration or the furniture are all very artistic and lovely. They were so refined and beautiful with their delicate taste which truly seem against our modern rationalism and uniformity.

• Korean Journal of Social Welfare
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• v.68 no.4
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• pp.119-141
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• 2016

This study analyzed on the basis of the norms and experience the Seongnam youth dividend ordinance. Youth dividend pros in the normative dimension to understand in order to achieve social justice. Further, youth dividend can replace the existing policy. On the other hand, the opposite of youth dividend is pointed out that the policy is ambiguous without morally justifiable. Also it has been pointed out inefficiencies means. Youth dividend Pros empirical dimension is a social considerations measures, there is a need for innovation by the failure of existing measures. On the other hand, youth dividend opposed to target efficiency is low, and that the problem is often to the contents of the salary. Because both sides are too contrast, consensus is difficult, can be political point of view is a significant impact. The basic income is a new thought experiment for human self-realization. Therefore, the production social welfare policy personality is a different policy science. That is, it is a long-term care social policy that requires a holistic life support. In addition, a non-empirical policy that requires a material support for the substantial freedom. Therefore, it is necessary to understand the philosophical meaning than scientific evaluation of traditional policy aiming to realize autonomous life. Therefore, radio waves of basic income through the welfare politics and exercise is still important strategy.

• Tuberculosis and Respiratory Diseases
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• v.79 no.3
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• pp.111-120
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• 2016

Asthma is a prevalent and serious health problem in Korea. Recently, the Korean Asthma Guideline has been updated by The Korean Academy of Tuberculosis and Respiratory Diseases (KATRD) in an effort to improve the clinical management of asthma. This guideline focuses on adult patients with asthma and aims to deliver up to date scientific evidence and recommendations to general physicians for the management of asthma. For this purpose, this guideline was updated following systematic review and meta-analysis of recent studies and adapting some points of international guidelines (Global Initiative for Asthma [GINA] report 2014, National Asthma Education and Prevention Program [NAEPP] 2007, British Thoracic Society [BTS/SIGN] asthma guideline 2012, and Canadian asthma guideline 2012). Updated issues include recommendations derived using the population, intervention, comparison, and outcomes (PICO) model, which produced 20 clinical questions on the management of asthma. It also covers a new definition of asthma, the importance of confirming various airflow limitations with spirometry, the epidemiology and the diagnostic flow of asthma in Korea, the importance and evidence for inhaled corticosteroids (ICS) and ICS/formoterol as a single maintenance and acute therapy in the stepwise management of asthma, assessment of severity of asthma and management of exacerbation, and an action plan to cope with exacerbation. This guideline includes clinical assessments, and treatment of asthma-chronic obstructive pulmonary disease overlap syndrome, management of asthma in specific conditions including severe asthma, elderly asthma, cough variant asthma, exercise-induced bronchial contraction, etc. The revised Korean Asthma Guideline is expected to be a useful resource in the management of asthma.

• Journal of Broadcast Engineering
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• v.14 no.6
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• pp.661-675
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• 2009

The carelessly and illegally copied contents are raising serious social problem as internet and multimedia technologies are advancing. Therefore, development of video copy detection system must be settled without delay. In this paper, we propose the hierarchical video copy detection method that estimates similarity using statistical characteristics between original video and manipulated(transformed) copy video. We rank according to luminance value of video to be robust to spacial transformation, and choose similar videos categorized as candidate segments in huge amount of database to reduce processing time and complexity. The copy videos generally insert black area in the edge of the image, so we remove rig black area and decide copy or not by using statistical characteristics of original video and copied video with center part of frame that contains important information of video. Experiment results show that the proposed method has similar keyframe accuracy to reference method, but we use less memory to save feature information than reference's, because the number of keyframes is less 61% than that of reference's. Also, the proposed method detects if the video is copied or not efficiently despite expansive spatial transformations such as blurring, contrast change, zoom in, zoom out, aspect ratio change, and caption insertion.

• Journal of Broadcast Engineering
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• v.13 no.6
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• pp.941-950
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• 2008

The quality of projector output image is influenced by the surrounding conditions such as the shape and color of screen, and environmental light. Therefore, techniques that ensure desirable image quality, regardless of such surrounding conditions, have been in demand and are being steadily developed. Among the techniques, radiometric compensation is a representative one. In general, radiometric compensation is achieved by measuring the color of the screen and environmental light based on an analysis of camera image of projector output image and then adjusting the color of projector input image in a pixel-wise manner. This process is not time-consuming for small sizes of images but the speed of the process drops linearly with respect to image size. In large sizes of images, therefore, reducing the time required for performing the process becomes a critical problem. Therefore, this paper proposes a fast radiometric compensation method. The method uses color filters for eliminating the color mixing between projector and camera because the speed of radiometric compensation depends mainly on measuring color mixing between projector and camera. By using color filters, there is no need to measure the color mixing. Through experiments, the proposed method improved the compensation speed by 44 percent while maintaining the projector output image quality. This method is expected to be a key technique for widespread use of projectors for large-scale and high-quality display.