• Quantitative Bio-Science
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• v.37 no.2
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• pp.133-141
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• 2018

Graphical lasso is one of the most popular methods to estimate a sparse precision matrix, which is an inverse of a covariance matrix. The objective function of graphical lasso imposes an ${\ell}_1$-penalty on the (vectorized) precision matrix, where a tuning parameter controls the strength of the penalization. The selection of the tuning parameter is practically and theoretically important since the performance of the estimation depends on an appropriate choice of tuning parameter. While information criteria (e.g. AIC, BIC, or extended BIC) have been widely used, they require an asymptotically unbiased estimator to select optimal tuning parameter. Thus, the biasedness of the ${\ell}_1$-regularized estimate in the graphical lasso may lead to a suboptimal tuning. In this paper, we propose a two-staged bias-correction procedure for the graphical lasso, where the first stage runs the usual graphical lasso and the second stage reruns the procedure with an additional constraint that zero estimates at the first stage remain zero. Our simulation and real data example show that the proposed bias correction improved on both edge recovery and estimation error compared to the single-staged graphical lasso.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.27 no.1
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• pp.26-33
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• 2019

It is necessary to establish a UAV pilot license and training system because the number of UAV-related accidents has rapidly risen. Most of accidents are caused by the human factors such as the lack of control skill and aviation knowledge. In this paper, we investigate licensing policy of small UAV pilots and examine the level of UAV licensing system and classification criteria based on comparative analysis of national cases such as USA, UK and China. Recently, the Ministry of Land, Infrastructure and Transport Affairs is planning to improve the safety regulation by taking into account the risk level of the licensing system, which has been classified according to the existing weight and commercial purpose. From the comparative analysis, we suggested a improvement policy for UAV licensing system in the view of pilot license segmentation, beyond Visual Line-of-sight flight and high risk UAV for non-commercial.

• Journal of Oral Medicine and Pain
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• v.46 no.2
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• pp.54-62
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• 2021

Sjögren's syndrome (SS) is an autoimmune rheumatic disease characterized by the presence of lymphocytic infiltration of exocrine glands and other organs. Due to the rarity of SS, it is frequently overlooked by dentists as a cause of xerostomia. Clinicians should be aware that patients may have oral complications from SS including oral mucosal pain caused by frictional damage. Use of the latest diagnostic criteria approved by the American College of Rheumatology/European League against Rheumatism in 2016 for SS diagnosis provides the advantage of early identification of patients who have not yet developed dry mouth symptoms. A case of primary SS with the chief complaint of oral mucosal pain caused by mucosal damage associated with dry mouth is presented here. This case represents the importance of recognizing oral complications of xerostomia caused by SS, and illustrates use of the latest diagnostic criteria to diagnose the suspected symptoms by dental clinicians, who typically might be the first medical professional to encounter these symptoms.

• Journal of the Korean Society of Systems Engineering
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• v.19 no.1
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• pp.79-90
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• 2023

In principle, R&D of general weapons systems are led by companies or government-funded organizations. In terms of project execution, the defense R&D planning system was reorganized to conduct SE-based project management by integrating the naval ship project execution procedure into the general weapon system R&D procedure. The development progress was confirmed according to the guide for SE application of DAPA, and a technical review meeting was proposed to enter into the each next phase in the R&D process. This paper focuses on improvement for technical review in terms of technical management based on system engineering for R&D mounted weapon systems and the naval surface ship project in preliminary design and detailed design. So, the improvement direction for reviewing the entry criteria for the R&D weapons systems of the naval ship and mounted weapons is proposed.

• Clinical and Experimental Pediatrics
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• v.45 no.3
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• pp.376-382
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• 2002

Purpose : To identify clinical and laboratory features of atypical Kawasaki disease(KD), and to develop criteria for early diagnosis of atypical KD patients. Methods : All patients with KD treated at our hospital from January 1998 to June 2000 were reviewed retrospectively. Results : Among a total of 167 patients, 28(16.8%) were atypical KD of which seven(25%) were infants. Among the five cardinal symptoms, oral mucosal change(96.4%) occurred most frequently, followed by conjuntivitis(57.1%) and rash(46.4%). Most notable laboratory findings were anemia, and increased erythrocyte sedementation rate(ESR) or C-reactive protein(CRP). Coronary artery abnormalities developed in seven(25.8%) atypical KD patients, compared with 14.4% in typical KD patients. We considered oral mucosal change as major criterion, and conjunctivitis, rash, hematocrit <35% and ESR >30 mm/hr or CRP >3.1 mg/dL as minor criteria. Proposed modification in diagnostic criteria for atypical KD include fever of ${\geq}5$ days＋major criterion＋${\geq}2$ minor criteria, or fever of ${\geq}5$ days＋4 minor criteria. Conclusion : The modified diagnostic criteria has yielded a sensitivity 89.3%. Our diagnostic criteria may be used for early diagnosis of atypical KD.

• Journal of The Korean Association For Science Education
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• v.37 no.5
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• pp.879-889
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• 2017

The purpose of this study is to develop the evaluation criteria for students' research reports on online science inquiry problems that promote thinking abilities. The steps of developing the evaluation criteria are as follows; First, based on previous study results and literature review, the evaluation categories of the science inquiry contents were determined: 1) knowledge, 2) logical and analytical thinking, 3) critical thinking, 4) science process skills, 5) problem-solving, and 6) creative thinking. Second, evaluation criteria are developed according to the following steps: 1) define each category, 2) identify sub-category, 3) develop evaluation criteria for all categories that could serve as guidelines in the development of scoring rubrics, and 4) expert validation processes were performed. Finally, the usability test for these evaluation categories and criteria were done by being applied to the development of real scoring rubrics for 24 problems included in e-learning contents. Then the users' feedbacks were filed and the implications of this study were discussed.

• Journal of Environmental Health Sciences
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• v.45 no.4
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• pp.370-380
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• 2019

Objective: This study was performed to investigate the distribution of individual exposure characteristics according to an exposure assessment classification for humidifier disinfectant and to identify the factors that influence assessment classification. Methods: We examined the exposure characteristics of 4,482 subjects who applied for the 4-1 and 4-2 assessments of environmental exposure to humidifier disinfectant conducted by the Korea Environmental Industry & Technology Institute (KEITI). Environmental exposure assessment classification was assessed using the following seven criteria: 1) Distance from humidifier to face; 2) Spray direction; 3) Time used, daytime 4) Time used, during sleep; 5) Time used, cumulative; 6) Exposure intensity; and 7) Cumulative exposure level. Each criteria was then classified as 'high' or low'. When participants answered for more than four criteria, exposure assessment was determined as 'definite,' 'probable,' or 'possible' depending on the ratio of 'high' responses. If participants' responses were inconsistent, exposure assessment was listed as 'unlikely.' If participants answered for less than four criteria, exposure assessment was considered 'indeterminate.' Results: For the exposure assessment classes, definite was assigned to 38.5% (1,725 subjects), probable assigned to 32.9% (1,474 subjects), 25.0% (1,122 subjects) were assigned to as possible, unlikely assigned to 0.1% (3 subjects), and indeterminate assigned to 3.5% (158 subjects). Overall, participants who used 'Oxy Ssakssak New Gaseupgi Dangbun,' 'Aekyung Gaseupgi Mate,' 'Homeplus Gaseupgi Chungjungje,' and 'E-Mart Gaseupgi Salgyunje' totaled 2,996, 557, 176, and 162 subjects, respectively. There was a statistical difference in the type of humidifier disinfectant products between high-exposed and low-exposed participants. Based on the assessment criteria of humidifier disinfectant exposure, subjects were likely to be in the highly exposed classes (definite and probable) when the subjects were exposed 1) for more than ten hours per day and 2) for more than four hours at night 3) when the total cumulative exposure time was higher than the average, 4) when the direction of humidifier spray was toward the face, 5) when the respiratory position was less than 1 meter of distance from the humidifier, 6) when the concentration of indoor contaminants (ug/m3) was higher than the average exposure intensity, and 7) when overall exposure level ($ug/m3^*hr$) was higher than the average exposure level. Conclusion: This study suggests that each exposure assessment criteria was able to appropriately estimate cumulative exposure levels.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.3187-3194
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• 2011

Vehicle dynamic behavior should be investigated to establish the track irregularity criteria because they have an impact on vehicle dynamic behavior. The tilting train which have been developed in Korea will be operated on the conventional line. Therefore, it should be checked that the track irregularity criteria of conventional line is still available for the new vehicle. In this paper, the influence of alignment on running behavior and safety for tilting train was instigated by numerical analysis. The wavelength and amplitude of alignment were considered in scenario of this numerical analysis. This research is based on just numerical analysis and the final result which include measurement will be published in the future.

• Transactions of Materials Processing
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• v.5 no.3
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• pp.219-231
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• 1996

The current five-stage cold extrusion process to produce an axle-housing is investigated for the purpose of improved process. The main goal of this study is to obtain an appropriate reduced process sequence which can produce the required part most economically without tensile crack-ing workpiece buckling and overloading of the tools. The current process sequence is simulated and design criteria are examined. during the simulation several remeshings are done due to severe mesh distortions, Based on the results of simulations of the current five-stage process, design strategy for improving the process sequence are developed using the thick hollow pipes. The finished product of an axle-housing is produced in two operations and one annealing treatment while the conventional sequence consists of five operations and one annealing treat-ment. Also die loads of the new process are compared with those of the current one.

• Journal of Acupuncture Research
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• v.29 no.4
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• pp.81-91
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• 2012

Objectives : There are numerous methods in treating acne scar. On the contrary there are hardly any cases on treating acne scars through Korean medicine. By observing we compared how much acne scar was treated by scar regeneration acupuncture therapy and micro-needle therapy treatment through observing pre and post case photos, KAGS, KCADI and patient satisfaction. Results : By comparing pre and post procedure through acne scar grade criteria, total of 5 patients showed improvement and could see distinct change in skin comparing case photos. After comparing pre and post procedures, total of 5 patients showed improvements in figures of Korean acne index. 4 patients replied very satisfied and 1 replies satisfied on patient satisfaction survey. Conclusions : After observing patients satisfaction, and comparing case photos, acne scar grade criteria, korean acne index, it can be considered that scar regeneration acupuncture therapy and micro-needle therapy done in our clinic to be valid treatment.