• Journal of Korean Neurosurgical Society
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• v.64 no.3
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• pp.418-426
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• 2021

Objective : A role of diffusion-weighted imaging (DWI) in the diagnosis of cerebral venous thrombosis (CVT) is not well-understood. This study evaluates the effectiveness of DWI in the diagnosis of CVT. Methods : Literature search was conducted in electronic databases for the identification of studies which reported the outcomes of patients subjected to DWI for CVT diagnosis. Random-effects meta-analyses were performed to achieve overall estimates of important diagnostic efficiency indices including hyperintense signal rate, the sensitivity and specificity of DWI in diagnosing CVT, and the apparent diffusion coefficient (ADC) of DWI signal areas and surrounding tissue. Results : Nineteen studies (443 patients with 856 CVTs; age 40 years [95% confidence interval (CI), 33 to 43]; 28% males [95% CI, 18 to 38]; symptom onset to DWI time 4.6 days [95% CI, 2.3 to 6.9]) were included. Hyperintense signals on DWI were detected in 40% (95% CI, 26 to 55) of the cases. The sensitivity of DWI for detecting CVT was 22% (95% CI, 11 to 34) but specificity was 98% (95% CI, 95 to 100). ADC values were quite heterogenous in DWI signal areas. However, generally the ADC values were lower in DWI signal areas than in surrounding normal areas (mean difference-0.33×10-3 ㎟/s [95% CI, -0.44 to -0.23]; p<0.00001). Conclusion : DWI has a low sensitivity in detecting CVT and thus has a high risk of missing many CVT cases. However, because of its high specificity, it may have supporting and exploratory roles in CVT diagnosis.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.899-904
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• 2022

As the world becomes an aging society due to a decrease in the birth rate and an increase in life expectancy, a system for health management of the elderly population is needed. Among them, various studies on occupancy and activity types are being conducted for smart home care services for indoor health management. In this paper, we propose a random forest model that classifies activity type as well as occupancy status through indoor temperature and humidity, CO2, fine dust values and UWB radar positioning for smart home care service. The experiment measures indoor environment and occupant positioning data at 2-second intervals using three sensors that measure indoor temperature and humidity, CO2, and fine dust and two UWB radars. The measured data is divided into 80% training set data and 20% test set data after correcting outliers and missing values, and the random forest model is applied to evaluate the list of important variables, accuracy, sensitivity, and specificity.

• Journal of Internet of Things and Convergence
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• v.9 no.2
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• pp.71-76
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• 2023

In this paper, we propose a smoothed received signal strength indicator (RSSI)-based distance estimation using deep neural network (DNN) for accurate distance estimation in an environment where a single receiver is used. The proposed scheme performs a data preprocessing consisting of data splitting, missing value imputation, and smoothing steps to improve distance estimation accuracy, thereby deriving the smoothed RSSI values. The derived smoothed RSSI values are used as input data of the Multi-Input Single-Output (MISO) DNN model, and are finally returned as an estimated distance in the output layer through input layer and hidden layer. To verify the superiority of the proposed scheme, we compared the performance of the proposed scheme with that of the linear regression-based distance estimation scheme. As a result, the proposed scheme showed 29.09% higher distance estimation accuracy than the linear regression-based distance estimation scheme.

• Atmosphere
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• v.33 no.1
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• pp.1-20
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• 2023

Holding the longest observation data from April 1904, Busan is one of the essential points to understand the climate variability of the Korean Peninsula without missing data since implementing the modern weather observation of the South Korea. Busan is featured by coastal areas and affected by various climate factors and fluctuations. This study aims to investigate climate variability and changes in climatic variables, extremes, and several weather indexes. The statistically significant change points in daily mean rainfall intensity and temperature were found in 1964 and 1965. Based on the change point detection, 117 years were divided into two periods for daily mean rainfall intensity and temperature, respectively. In the long-term temperature analysis of Busan, the increasing trend of the daily maximum temperature during the period of 1965~2021 was larger than the daily mean temperature and the daily minimum temperature. Applying Ensemble Empirical Mode Decomposition, daily maximum temperature is largely affected by the decadal variability compared to the daily mean and minimum temperature. In addition, the trend of daily precipitation intensity from 1964~2021 shows a value of about 0.50 mm day^-1, suggesting that the rainfall intensity has increased compared to the preceding period. The results in extremes analysis demonstrate that return values of both extreme temperatures and precipitation show higher values in the latter than in the former period, indicating that the intensity of the current extreme phenomenon increases. For Wet-Bulb Globe Temperature (effective humidity), increasing (decreasing) trend is significant in Busan with the second (third)-largest change among four stations.

• Asia Marketing Journal
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• v.11 no.3
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• pp.151-165
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• 2009

The objective of this case study is to analyze how effectively KIA SOUL, which is a leading Crossover Utility Vehicle (CUV) brand, has created a new market space through innovative product strategy. Up until now, most car manufacturers have focused only on the traditional product market segments missing out on the opportunity of the crossover segment market. KIA SOUL found a new market space by identifying the high crossover utility demand and filling the gap between the current product category values and the emerging crossover product category values. This case study illustrates that an innovative product strategy can be effectively employed to create a new market space in the saturated car manufacturing industry. The case summarizes that the innovative product strategy of KIA SOUL is comprised of four primary pillars: design innovation, market frontier in CUV, the first company to launch customizing service brand-TUON, and functional innovation. The KIA SOUL case study provides valuable insights and implications for many other companies that are planning to find "blue oceans" for their own business.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.2
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• pp.187-195
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• 2024

Purpose : Many studies have confirmed the relationship between physical exercise, chronic diseases, and quality of life, but few of those studies were limited to aerobic exercise. Above all, no research has confirmed the relationship between aerobic exercise and the oral health. This study is significant because it is the first study to confirm the relationship between aerobic exercise, which is practiced more frequently than other exercises, and oral health in adults. Through this study, we hoped to confirm the complex impacts of aerobic exercise on health-related quality of life, oral health-related behavior, and oral health status in adults and to use these impacts as basic data on the importance of aerobic exercise. Methods : In this study, the following analysis was conducted based on a complex sample design that applied stratification variables, cluster variables, and weights using SPSS version 21.0. Complex sample cross-analysis was conducted to identify general characteristics according to aerobic physical activity practice, and oral health-related characteristics according to the aerobic physical activity practice rate. Then, complex sample logistic regression analysis was conducted to determine the effect of aerobic physical activity practice on oral health-related characteristics. During the statistical analysis, missing values were treated as valid values, and the statistical significance level was set at .05. Results : Aerobic physical activity practice was 1.39 times higher among the respondents who brushed their teeth after lunch (p<.001), 1.43 times higher among those who used dental floss (p<.001), 1.24 times higher among those who used mouthwash (p=.040), and 1.37 times higher was among those who had not experienced dental treatment (p=.040), which were statistically significant differences. Conclusion : This study found that when an individual's health status is maintained, positive oral health behavior can be achieved by paying attention to oral health, and this appears to contribute to improving oral health.

• Journal of Korean Society for Quality Management
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• v.52 no.2
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• pp.255-274
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• 2024

Purpose: Non-Fungible Token (NFT) ART, based on NFT technology, represents a novel form of art that has recently garnered significant attention in the art market. NFT technology enables the assertion of ownership over digital data, introducing the concept of ownership into the digital realm. As digital data gains ownership, NFT ART is anticipated to be positively viewed as an investment and expected to become more active due to the characteristics of this new technology. Therefore, this study aims to verify the influence of NFT ART characteristics on perceived value. This study contributes to extracting the distinctive characteristics of NFT ART compared to other forms of art and to understanding the perceived value of NFT ART among consumers with purchasing experience. Methods: This study applied structural equation modeling to explore the relationships among the variables using SPSS 26.0 and R program version 4.2.3. A total of 320 questionnaires were retrieved, all of which were adopted as valid analytical samples without missing values. Results: The findings indicate that the decentralization, transparency, and scarcity of NFT ART positively influence the perceived usefulness and enjoyment among consumers, while security does not have a significant impact. This suggests that higher levels of decentralization, transparency, and scarcity in NFT ART enhance perceived usefulness and enjoyment for consumers, significantly influencing the perceived value. Furthermore, it was confirmed that these characteristics are considered important values and perceptions from the consumer's perspective. Conclusion: The research presents positive factors for the activating of purchases among consumers considering buying NFT ART. It emphasizes the necessity of benefits for all participants to activate the art market. Additionally, the perceived value provides crucial insights for inducing active purchasing behavior in the NFT ART market and serves as a foundational study for further research.

• The korean journal of orthodontics
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• v.40 no.2
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• pp.95-105
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• 2010

Objective: To identify clinical, salivary, and bacterial changes during orthodontic treatment with follow-up to 24 months. Methods: In 30 patients, clinical (decayed, missing, and filled surfaces [DMFS], O'Leary's plaque index, and plaque pH), salivary (unstimulated and stimulated saliva, buffer capacity, pH, and occult blood), and bacterial (Streptococcus mutans and Lactobacillus) markers were evaluated. A questionnaire was employed to evaluate their hygienic-dietary habits. Data were analyzed by ANOVA, logistic regression and Spearman's correlation. Results: DMFS increased significantly, whereas the plaque index diminished, plaque pH was more acidic (p = 0.23), and unstimulated salivary flow showed significant differences during the treatment (p = 0.013). Stimulated saliva flow increased in females after the placement of appliances; buffer capacity was diminished in males during the therapy; salivary pH remained at basal values. Bacterial levels and occult blood increased to high-risk levels and were not statistically significant different between genders (p > 0.05). Two major relationships were confirmed: initial plaque with use of dental aids (r = 0.429; p = 0.018) and final DMFS with unstimulated salivary flow (r = -0.372; p = 0.043). Conclusions: The increase in retentive surfaces increased the bacterial levels, plaque pH became acidified, and gingival damage was greater. Buffer capacity was altered but maintained a healthy salivary pH during the treatment.

• Environmental Analysis Health and Toxicology
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• v.20 no.4 s.51
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• pp.311-325
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• 2005

A chemical ranking and scoring system, CRS - Korea, has recently been developed and proposed to use to prioritize on a screening level the toxic chemicals for monitoring and risk assessment. As CRS-Korea requires rigorous assessments prior to its wide application, an assessment was conducted in this study by examining the contribution of individual parameter score to the final chemical score or ranking. The sensitivity of the system to the default values for various parameters of missing data was also tested. The chemical ranking/score was round to depend primarily on the score of a single parameter, i. e., the chemical release, while toxicity scores show little correlation with the priority Further analysis indicated that the dominating effect of the chemical release results from i) its multiplicative relationship with the other two exposure parameters (biodegradation and persistent) and ii) the fact that a maximum score of 10 was assigned to the chemical release parameter while 5 was assigned for all others. AE the fraction of the data that are missing exceeded $70\%$ for various toxicity parameters at compared to less than $10\%$ for exposure parameters, the sensitivity of the ranking to the default value was not significant (rank correlation coefficient = 0.98) for toxicity parameters. Bated on this assessment, an improved CRS system (CRS - Korea II) was proposed in which the impact of the chemical release was properly adjusted by changing the multiplicative relationship to additive one and the maximum score to 5. Chemical priority was derived for each of 16 provinces by using CRS-Korea II. The chemical priority was found to significantly vary among the provinces. It was concluded that not only the national chemical priority but the local chemical priority should be taken into account in setting the nationwide chemical monitoring and risk assessment strategy.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.26-36
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• 2006

In this paper, we propose a cost-effective color filter may (CFA) demosaicing method for digital still cameras in which a single CCD or CMOS image sensor is used. Since a CFA is adopted, we must interpolate missing color values in the red, green and blue channels at each pixel location. While most state-of-the-art algorithms invest a great deal of computational effort in the enhancement of the reconstructed image to overcome the color artifacts, we focus on eliminating the color artifacts with low computational complexity. Using spatial correlation of the adjacent pixels, the edge-directional information of the neighbor pixels is used for determining the edge direction of the current pixel. We apply our method to the state-of-the-art algorithms which use edge-directed methods to interpolate the missing color channels. The experiment results show that the proposed method enhances the demosaiced image qualify from $0.09{\sim}0.47dB$ in PSNR depending on the basis algorithm by removing most of the color artifacts. The proposed method was implemented and verified successfully using verilog HDL and FPGA. It was synthesized to gate-level circuits using 0.25um CMOS standard cell library. The total logic gate count is 12K, and five line memories are used.