• The Korean Journal of Applied Statistics
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• v.34 no.3
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• pp.309-327
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• 2021

Dynamic treatment regimes (DTRs) are decision-making rules designed to provide personalized treatment to individuals in multi-stage randomized trials. Unlike classical methods, in which all individuals are prescribed the same type of treatment, DTRs prescribe patient-tailored treatments which take into account individual characteristics that may change over time. The Q-learning method, one of regression-based algorithms to figure out optimal treatment rules, becomes more popular as it can be easily implemented. However, the performance of the Q-learning algorithm heavily relies on the correct specification of the Q-function for response, especially in observational studies. In this article, we examine a number of double-robust weighted least-squares estimating methods for Q-learning in high-dimensional settings, where treatment models for propensity score and penalization for sparse estimation are also investigated. We further consider flexible ensemble machine learning methods for the treatment model to achieve double-robustness, so that optimal decision rule can be correctly estimated as long as at least one of the outcome model or treatment model is correct. Extensive simulation studies show that the proposed methods work well with practical sample sizes. The practical utility of the proposed methods is proven with real data example.

• The Journal of Bigdata
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• v.5 no.2
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• pp.187-199
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• 2020

The World Health Organization declared COVID-19 a pandemic on March 11. South Korea recorded 27,000 cases of the coronavirus illness, and more than 50 million coronavirus cases were confirmed all over the world. An epidemiological investigation becomes important once again due to the spread of COVID-19 infections. However, there were a number of confirmed coronavirus cases from Deagu and Gyeongbuk. Limitations of the epidemiological investigation methods were recognized. The Korea Disease Control and Prevention Agency developed the Epidemiological Investigation Support System(EISS) to utilize the smart city data hub technology and utilized the system in the epidemiological investigation. As a part of EISS, The proposed system is big-data bsed epidemiological investigation support system processing mobile network data. The established system is the epidemiological investigation support system based on big data to process mobile carriers' big data. Processing abnormal values of mobile carriers' data which was impossible with existing staff or creating hotspot regions where more than two people were in contact with an infected person were realized. As a result, our system processes outlier of mobile network data in 30 seconds, while processes hotspot around in 10 minutes. as a first time to adapt and support bigdata system into epidemiological investigation, our system proposes the practical utilizability of big-data system into epidemiological investigation.

• The Journal of Pediatrics of Korean Medicine
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• v.35 no.1
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• pp.122-138
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• 2021

Objectives The purpose of this study is to widely utilize the clinical practice guideline for autism spectrum disorder (ASD) by investigating parents who have children with ASD about their perception in ASD and their thoughts on Korean medicine treatment to treat ASD. Methods We conducted a survey on 'perception of ASD' and 'perception and preference of Korean medicine treatment for ASD' on the parents of 22 children with ASD (age 4-6) who visited department of pediatrics of Korean medicine at Kyunghee University Korean medicine hospital at Gangdong and Kyunghee University Korean medicine hospital. Results Of the parents, 20 (90.91%) said their children had no experience with Korean medicine treatment. Among them, 11 (35.48%) chose 'I didn't know that Korean medicine treats ASD' for the reason (multiple choice). When questioned what the worries are for Korean medicine treatment, 13 (30.95%) chose 'worries about probability of side effects of herbal medicine' as the most worrisome reason (multiple choice). On the question about the necessity of Korean medicine for the treatment of ASD, most chose 'Korean medicine treatments are necessary for children with ASD' (9, 40.91%). Conclusions It is necessary to develop a clinical practice guideline that reflects comprehensive evidence for side effects as well as the effectiveness of Korean medicine for ASD, and is necessary to promote the effectiveness and evidence-based Korean medicine treatment to patients and their caregivers through various distribution tools.

• Clean Technology
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• v.27 no.1
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• pp.17-23
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• 2021

Black polymer spacers are currently used for physically separating aligned camera lenses in camera modules of mobile phones. However, the mechanical properties of polymer spacers have their limits, especially in the current trend of using more lenses in thinner camera modules. Thus, copper (Cu) becomes a good candidate for those polymer spacers because of its superior mechanical properties and its inherent blackness due to its black surfaced oxides, such as copper (II) oxide (cupric oxide, CuO). The latter property is critical in quality control because the closer the color of a spacer is to black, the less light interference and flaring phenomena can occur. A standard Cu blackening process and its operational conditions were proposed in this study through a comprehensive analysis of previous research and patents. The Cu blackening process is composed of cleaning, deoxidizing, activating, blackening and sealing. The effects of operational parameters, such as the temperature of each unit process and the activator concentration, were then investigated by measuring the blackness of the Cu strips with a colorimeter. The proposed operational conditions were determined by whether the blackness of Cu strips was within the on-spec. value used in the field.

• Journal of Broadcast Engineering
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• v.27 no.3
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• pp.273-282
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• 2022

MPEG-VCM(Video Coding for Machine) aims to standardize video codec for machines. VCM provides data sets and anchors, which provide reference data for comparison, for several machine vision tasks including object detection, object segmentation, and object tracking. The evaluation template can be used to compare compression and machine vision task performance between anchor data and various proposed video codecs. However, performance comparison is carried out separately for each machine vision task, and information related to performance evaluation of multiple machine vision tasks on a single bitstream is not provided currently. In this paper, we propose a performance evaluation method of a video codec for AI-based multi-tasks. Based on bits per pixel (BPP), which is the measure of a single bitstream size, and mean average precision(mAP), which is the accuracy measure of each task, we define three criteria for multi-task performance evaluation such as arithmetic average, weighted average, and harmonic average, and to calculate the multi-tasks performance results based on the mAP values. In addition, as the dynamic range of mAP may very different from task to task, performance results for multi-tasks are calculated and evaluated based on the normalized mAP in order to prevent a problem that would be happened because of the dynamic range.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.4
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• pp.481-491
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• 2022

This study investigates the characteristics of the GAC adsorption behavior during the operation of a multi-stage cross-flow filtration and GAC adsorption process for the purpose of devising an advanced treatment of combined sewer overflows (CSOs) and evaluates the regeneration efficiency of spent GAC that has reached the design breakpoint. During the filtration process, suspended substances are easily removed, but dissolved organic substances are not removed, necessitating a process capable of removing dissolved organic substances for the advanced treatment of CSOs. In general, GAC adsorption has been applied under low-concentration organic conditions, such as for water purification and tertiary treatments of sewage, and has rarely been applied under conditions with high organic concentrations, such as with sewage or CSOs. Accordingly, this study will provide a new and interesting experience. Also in this study, the continuous operation and breakthrough characteristics of GAC according to the strength of the inflow organic matter were investigated, electrochemical regeneration was applied to the used GAC, and the regeneration efficiency was evaluated through desorption and re-adsorption tests. The results showed that the breakthrough period was 21 days under high concentration conditions, 28 days at medium concentrations, and 32 days under low concentration conditions. The desorption of adsorbed organic matter through electrolysis occurred in the range of 188 to 609 mgCOD/L depending on the electrolysis conditions, and the effect of the electrolyte type led to the finding that NaOH was slightly higher than H₂O₂.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.48 no.2
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• pp.135-146
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• 2022

In order to prevent microbial contamination and safely use cosmetics, it is essential to possess preservative power. In this study, the antifungal effect was confirmed by improving the preservative system of the aqueous dispersion formulation, which has a weak preservative power against fungi, and various preservative systems were established to strengthen the preservative power against fungi. Five kinds of raw materials (sodium anisate, p-anisic acid, caprylhydroxamic acid, o-cymen-5-ol, hydroxyacetophenone) that have a benzene ring structure having a hydroxyl group and exist as protonated form in cosmetic formulations expected to improve antifungal activity in cosmetics were selected, and the minimum growth inhibitory concentration of the raw materials was determined through MIC assay. It was confirmed that the preservative power against mold was improved through the preservative efficacy test of 4 types of water dispersion formulations (cream, lotion, toner, and sun cream) in which 4 types of raw materials showing antimicrobial activity against mold were added to the preservative system. When p-anisic acid was used, it was confirmed that the preservative activity against mold was strengthened without the effect of inhibiting the preservative power against bacteria and yeast in all four formulations.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.3
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• pp.263-275
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• 2022

The loss of posterior occlusal support leads to further complications such as collapsed occlusal plane and reduced vertical dimension, and it may cause problems such as facial appearance change, reduced chewing efficiency, and temporomandibular joint disorders. In such case, it is necessary to re-establish occlusal plane and vertical dimension properly through accurate diagnosis and predictable treatment plan. This case report presents a 71-year-old female, whose occlusal plane was collapsed and posterior restorative space was insufficient. To perform a patient-friendly full mouth rehabilitation, proper vertical dimension and occlusal plane were decided by evaluation of interocclusal space at her physiologic mandibular rest position, swallowing, pronunciation, facial appearance, and the average length of anterior teeth. And then, the fixed provisional restorations were fabricated with the new occlusal position, and evaluated for 5 months with checking adaptation of masticatory muscles and any kind of clinical symptoms occurs or not. After confirmation of functional stability and esthetic satisfaction with the newly established occlusion, final definitive restorations were fabricated and inserted in the mouth. Through the above process, the treatment result was functionally and aesthetically satisfactory.

• Ecology and Resilient Infrastructure
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• v.9 no.2
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• pp.107-112
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• 2022

This study was conducted to investigate the effects of mulching materials in extensive green roof system by comparing and analyzing the soil moisture content and growth response of Lychnis cognata according to the types of organic mulching materials. The experimental group consisted of a control group that did not use mulching material (Cont.) and a total of five treatment groups, including cocochip (C.O), woodchip (W.O), straw (S.T), and sawdust (S.A), depending on the mulching material. The soil moisture content according to the type of organic mulching material was high in the order of W.O > S.T > Cont. > C.O > S.A, and there was a significant difference especially in S.A. The plant height showed good growth in the order of S.T > Cont. > C.O > W.O > S.A, and there was no significant difference by mulching materials in other growth items except for plant height. Both the chlorophyll and plant water contents were superior to those of untreated group, so the treatment of organic mulching materials is considered to be effective in maintaining the chlorophyll and plant water contents of Lychnis cognata. In particular, the soil moisture content was affected by the characteristics of the mulching material itself. Based on these results, it is required to use a mulching material suitable for the characteristics of each plant in extensive green roof system and it is considered that this can be overcome through organic mulching when selecting a plant species that is weak to water stress.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.1
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• pp.21-30
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• 2022

Objectives: The purpose of this study is to suggest an optimal method by comparing the analysis methods of work environment measurement datasets including left-censored data where one or more measurements are below the limit of detection (LOD). Methods: A computer program was used to generate left-censored datasets for various combinations of censoring rate (1% to 90%) and sample size (30 to 300). For the analysis of the censored data, the simple substitution method (LOD/2), β-substitution method, maximum likelihood estimation (MLE) method, Bayesian method, and regression on order statistics (ROS)were all compared. Each method was used to estimate four parameters of the log-normal distribution: (1) geometric mean (GM), (2) geometric standard deviation (GSD), (3) 95th percentile (X95), and (4) arithmetic mean (AM) for the censored dataset. The performance of each method was evaluated using relative bias and relative root mean squared error (rMSE). Results: In the case of the largest sample size (n=300), when the censoring rate was less than 40%, the relative bias and rMSE were small for all five methods. When the censoring rate was large (70%, 90%), the simple substitution method was inappropriate because the relative bias was the largest, regardless of the sample size. When the sample size was small and the censoring rate was large, the Bayesian method, the β-substitution method, and the MLE method showed the smallest relative bias. Conclusions: The accuracy and precision of all methods tended to increase as the sample size was larger and the censoring rate was smaller. The simple substitution method was inappropriate when the censoring rate was high, and the β-substitution method, MLE method, and Bayesian method can be widely applied.