• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.4
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• pp.423-436
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• 2011

Trauma from occlusion (TFO) is a pathologic alterations which develop in the periodontium as a result of undue masticatory force. The purpose of this article is to review the controversies about TFO. There are evidences that TFO is a risk factor in the progression of periodontitis. Tooth mobility should be reduced by selective occlusal adjustment. TFO can be developed dependent on the masticatory pattern, occlusion and anterior overbite in sound periodontal conditions. Secondary TFO may aggravate unstable occlusion. If "loss of posterior support" was occur, the problems were worsen. Extrusion, migration, rotation and pathologic deviation can be resulted. Opposite contention is the "shortened dental arch" concept. However, these two concepts persue the occlusal stability together. To treat TFO adequately, exact diagnosis and multi-disciplinary treatment should be needed.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.2
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• pp.65-72
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• 2012

In the 21st century of information systems, the amount of information resources are ever increasing and the role of information searching system is becoming criticalto easily acquire required information from the web. Generally, it requires the user to have enough pre-knowledge and superior capabilities to identify keywords of information to effectively search the web. However, most of the users undertake searching of the information without holding enough pre-knowledge and spend a lot of time associating key words which are related to their required information. Furthermore, many search engines support the keywords searching system but this only provides collection of similar words, and do not provide the user with exact relational search information with the keywords. Therefore this research report proposes a method of offering expanded user relationship search keywords by analyzing user query patterns to provide the user a system, which conveniently support their searching of the information.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.9
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• pp.4301-4306
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• 2016

Background: Cancer is a burden on humanity and ranks as a leading cause of morbidity and mortality in China. Shanxi province has its unique cancer patterns and the burden is increasing. In this study, we aimed to assess the pattern of dietary habits and life-style in Shanxi, a high-risk area for upper gastrointestinal cancers in China and further evaluate the trends in cancer incidence and mortality based on registered data. Materials and Methods: Data on lifestyle, diet, physical activity were obtained from the household health survey at Zhongyang from 2013 to 2015. Cancer diagnoses were reported to Shanxi Center for Disease Control and Prevention (SCDCP). Population-based cancer incidence data and mortality data of 2012 were collected from the SCDCP. All incidence and death rates were expressed per 100,000 populations. Univariate analysis was performed using the Chi-squared test or Fisher's exact test. Results: Overall, deficiencies in fresh fruits and vegetable food, and intake of hot food, salted food, or pickled food are serious problems in Shanxi, especially in rural areas. Upper gastrointestinal cancers were the most commonly diagnosed cancers, and the incidence in rural areas is higher than those in urban areas. Cervical cancer is the most common cancer for females. Moreover, the agespecific incidence exhibited an increased trend before 40 years old. Consistent with the previous literature, our epidemiological investigation results suggest that lifestyle, nutrition deficient, and infections were major risk factors for upper gastrointestinal cancers or cervical cancer in Shanxi. Facing a serious situation, we further explored defensible recommendations for the general public in order to promote changes in environments that support healthful eating and physical activity habits, to reduce cancer risk. Conclusions: Our results present the current cancer trends in Shanxi and its related etiologic risk factors and provide a theoretical basis to guide public health efforts to prevent and control cancers in the province.

• ETRI Journal
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• v.36 no.1
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• pp.134-140
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• 2014

Many reports have shown that the access pattern for geospatial tiles follows Zipf's law and that its parameter ${\alpha}$ represents the access characteristics. However, visits to geospatial tiles have temporal and spatial popularities, and the ${\alpha}$-value changes as they change. We construct a mathematical model to simulate the user's access behavior by studying the attributes of frequently visited tile objects to determine parameter estimation algorithms. Because the least squares (LS) method in common use cannot obtain an exact ${\alpha}$-value and does not provide a suitable fit to data for frequently visited tiles, we present a new approach, which uses a moment method of estimation to obtain the value of ${\alpha}$ when ${\alpha}$ is close to 1. When ${\alpha}$ is further away from 1, the method uses the associated cache hit ratio for tile access and uses an LS method based on a critical cache size to estimate the value of ${\alpha}$. The decrease in the estimation error is presented and discussed in the section on experiment results. This new method, which provides a more accurate estimate of ${\alpha}$ than earlier methods, promises more effective prediction of requests for frequently accessed tiles for better caching and load balancing.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.6
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• pp.527-533
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• 2013

BCI (Brain-Computer Interface) is a system that transforms a subject's brain signal related to their intention into a control signal by classifying EEG (electroencephalograph) signals obtained during the imagination of movement of a subject's limbs. The BCI system allows us to control machines such as robot arms or wheelchairs only by imaging limbs. With the exact same experiment environment, activated brain regions of each subjects are totally different. In that case, a simple approach is to use as many channels as possible when measuring brain signals. However the problem is that using many channels also causes other problems. When applying a CSP (Common Spatial Pattern), which is an EEG extraction method, many channels cause an overfitting problem, and in addition there is difficulty using this technique for medical analysis. To overcome these problems, we suggest an optimal channel selection method using a BPSO (Binary Particle Swarm Optimization), BPSO with channel impact factor, and GA. This paper examined optimal selected channels among all channels using three optimization methods and compared the classification accuracy and the number of selected channels between BPSO, BPSO with channel impact factor, and GA by SVM (Support Vector Machine). The result showed that BPSO with channel impact factor selected 2 fewer channels and even improved accuracy by 10.17~11.34% compared with BPSO and GA.

• Journal of Korean Neurosurgical Society
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• v.46 no.2
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• pp.136-143
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• 2009

Objective: Remote cerebellar hemorrhage (RCH) is one of the rare complications occurring after supratentorial surgery, and its pathomechanism is poorly understood. We report 10 cases of RCH from our institution and review 154 cases from a database in order to delineate incidence, common presentation, risk factors, and outcomes of this complication. In addition, the means of prevention are discussed. Methods: We reviewed the medical records of 10 patients who experienced RCH after undergoing supratentorial surgery at our institution between 2001 and 2008. A database search in Medline revealed 154 cases of RCH in the English literature. Characteristic features were analyzed and compared. Results: There were 10 cases of RCH among 3307 supratentorial surgery cases, indicating a 0.3% incidence. All patients had characteristic imaging features of RCH, namely a streaky bleeding pattern in the superior folia of the cerebellum. Seven patients had a history of preoperative hypertension. Four cases were related to cerebral aneurysms, and other four developed after the removal of brain tumors. Cerebrospinal fluid (CSF) drainage apparatuses were installed postoperatively in all cases. Outcomes according to modified Rankin scale (mRS) were good in 7 patients, with 1 fatal case. Conclusion: RCH is a rare complication after supratentorial surgery, and the exact etiology still remains uncertain. Hypertension and perioperative loss of CSF seem positively correlated with RCH, but no single risk factor is totally responsible. Patients with RCH should be closely observed to improve their prognosis.

• Journal of Korean Neurosurgical Society
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• v.46 no.4
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• pp.333-339
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• 2009

Objective : Few studies on the clinical spectrum of automated pressure-controlled discography (APCD)-defined positive discs have been reported to date. Thus, the present study was undertaken to analyze clinical parameters critical for diagnosis of discogenic pain and to correlate imaging findings with intradiscal pressures and pain responses in patients with APCD-positive discs. Methods : Twenty-three patients who showed APCD-positive discs were selected for analysis. CT discogram findings and the degrees of nuclear degeneration seen on MRI were analyzed in comparison to changes of intradiscal pressure that provoked pain responses; and clinical pain patterns and dynamic factors were evaluated in relation to pain provocation. Results : Low back pain (LBP), usually centralized, with diffuse leg pain was the most frequently reported pattern of pain in these patients. Overall, LBP was most commonly induced by sitting posture, however, standing was highly correlated with L5/S1 disc lesions (p<0.01). MRI abnormalities were statistically correlated with grading of CT discogram results (p<005); with most pain response observed in CT discogram Grades 3 and 4. Pain-provoking pressure was not statistically correlated with MRI grading. However, it was higher in Grade 3 than Grade 4. Conclusion : APCD-positive discs were demonstrated in patients reporting centralized low back pain with diffuse leg pain, aggravated by sitting and standing. MRI was helpful to assess the degree of nuclear degeneration, yet it could not guarantee exact localization of the painful discs. APCD was considered to be more useful than conventional discography for diagnosis of discogenic pain.

• Journal of Preventive Medicine and Public Health
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• v.40 no.3
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• pp.239-248
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• 2007

Objectives : This study was conducted to investigate the systematic error, such as seasonal change or inadequate food items, in a food frequency questionnaire administered to workers in a Nuclear Power Plant, Korea. Methods : We performed three repeat-tests with 28 subjects on May 13, July 8 and Dec 16, 1992. Our food frequency questionnaire (FFQ) comprised 84 foods organized into 7 food-groups, and was composed of the items of usual intake frequency (8 categories) and the amount per intake (3 or 4 categories) over the previous year. We compared the means of intake frequency and the frequency of the portion-size according to each season using Repeated Measures ANOVA and Pearson's chisquare test with Fisher's exact test. Results : We found the significant seasonal changes of several food items in intake frequency measurement. These items were typical seasonal foods such as mandarin orange, plum and green vegetables, while the single questions consisted of inadequate food items such as thick beef or similar soup and various kimchi products. Significant seasonal changes in portion-size were found in only two items: cooked rice-brown and fresh frozen fishes. Conclusions : The systematic errors observed could caused loss of validity in the FFQ. Consideration should be given for seasonal variation in FFQ survey and methodological concerns are needed to improve the quality for measuring usual diet pattern.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.436-437
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• 2012

Double patterning technology (DPT) has been suggested as a promising candidates of the next generation lithography technology in FLASH and DRAM manufacturing in sub-40nm technology node. DPT enables to overcome the physical limitation of optical lithography, and it is expected to be continued as long as e-beam lithography takes place in manufacturing. Several different processes for DPT are currently available in practice, and they are litho-litho-etch (LLE), litho-etch-litho-etch (LELE), litho-freeze-litho-etch (LFLE), and self-aligned double patterning (SADP) [1]. The self-aligned approach is regarded as more suitable for mass production, but it requires precise control of sidewall space etch profile for the exact definition of hard mask layer. In this paper, we propose etch end point detection (EPD) in spacer etching to precisely control sidewall profile in SADP. Conventional etch EPD notify the end point after or on-set of a layer being etched is removed, but the EPD in spacer etch should land-off exactly after surface removal while the spacer is still remained. Precise control of real-time in-situ EPD may help to control the size of spacer to realize desired pattern geometry. To demonstrate the capability of spacer-etch EPD, we fabricated metal line structure on silicon dioxide layer and spacer deposition layer with silicon nitride. While blanket etch of the spacer layer takes place in inductively coupled plasma-reactive ion etching (ICP-RIE), in-situ monitoring of plasma chemistry is performed using optical emission spectroscopy (OES), and the acquired data is stored in a local computer. Through offline analysis of the acquired OES data with respect to etch gas and by-product chemistry, a representative EPD time traces signal is derived. We found that the SE-EPD is useful for precise control of spacer etching in DPT, and we are continuously developing real-time SE-EPD methodology employing cumulative sum (CUSUM) control chart [2].

• Journal of Korean society of Dental Hygiene
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• v.16 no.1
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• pp.27-35
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• 2016

Objectives: The purpose of the study was to find out dental caries and periodontal disease based on oral healthcare of adults in Busan. This study will provide the preventive oral healthcare for the periodontal diseases and dental caries. Methods: The study subjects were 369 people from the regular dental health checkup in the general hospital in Busan. After receiving informed consent, a self-reported questionnaire was completed from October 1, 2014 to January 31, 2015. The questionnaire consisted of dental caries and periodontal diseases by direct examination and toothbrushing method. Data were analyzed by ${\chi}^2$ test, Fisher's exact test, and Pearson's correlation. Results: In the morbidity of dental caries and periodontal diseases, the dental caries was most common in those having restored teeth(236 subjects, 64%), while periodontal diseases were found in mild cases of gingival inflammation in 285 subjects(77.2%), and mild cases of dental calculus in 274 subjects(73.4%). Most of the respondents replied that they did not have systemic disease or oral health related symptoms. According to toothbrushing pattern, dental caries experiences were most common in those having less frequent toothbrushing less than 3 minutes and no tongue brushing. The outbreak of dental caries was more common in 5 times than 3 to 4 times a day. Conclusions: The education of the right toothbrushing method and use of dental floss is the most important prevention of dental caries and periodontal disease in the adults.