• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.9
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• pp.2991-3007
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• 2022

Two dimensional locality preserving projections (2D-LPP) is an improved algorithm of 2D image to solve the small sample size (SSS) problems which locality preserving projections (LPP) meets. It's able to find the low dimension manifold mapping that not only preserves local information but also detects manifold embedded in original data spaces. However, 2D-LPP is simple and elegant. So, inspired by the comparison experiments between two dimensional linear discriminant analysis (2D-LDA) and linear discriminant analysis (LDA) which indicated that matrix based methods don't always perform better even when training samples are limited, we surmise 2D-LPP may meet the same limitation as 2D-LDA and propose a novel matrix exponential method to enhance the performance of 2D-LPP. 2D-MELPP is equivalent to employing distance diffusion mapping to transform original images into a new space, and margins between labels are broadened, which is beneficial for solving classification problems. Nonetheless, the computational time complexity of 2D-MELPP is extremely high. In this paper, we replace some of matrix multiplications with multiple multiplications to save the memory cost and provide an efficient way for solving 2D-MELPP. We test it on public databases: random 3D data set, ORL, AR face database and Polyu Palmprint database and compare it with other 2D methods like 2D-LDA, 2D-LPP and 1D methods like LPP and exponential locality preserving projections (ELPP), finding it outperforms than others in recognition accuracy. We also compare different dimensions of projection vector and record the cost time on the ORL, AR face database and Polyu Palmprint database. The experiment results above proves that our advanced algorithm has a better performance on 3 independent public databases.

• Journal of Korea Trade
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• v.24 no.6
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• pp.1-18
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• 2020

Purpose - This study investigates whether a listing effect exists in cross-border M&As and whether the effect can be attributed to the uncertainty of the GDP growth rate in the target firm's home country. We apply a joint variable analysis using M&A announcement data from the Korea Exchange (KRX), Shanghai Stock Exchange (SSE), and the Taiwan Stock Exchange (TWSE) from 2004 to 2013. We also conduct an event study using the measure of the uncertainty of the GDP growth rate (based on IMF statistics) in 55 target countries. Design/methodology - We measure the abnormal return (AR) using the market-adjusted model. We test the significance of the AR and the cumulative abnormal return (CAR) using a one-sample t-test. We examine the characteristics of the CARs depending on whether the target company is listed by applying a difference analysis using CAR as a test variable. In addition, we set CAR (-5, +5) as a dependent variable to identify the cause of the listing effect, and test both the financial characteristic variables of the acquirer and the collective characteristic variables of the merger as independent variables in the multiple regression analysis. Findings - First, we find the listing effect of cross-border M&As in the KRX, SSE, and TWSE, which represent the capital markets in Korea, China, and Taiwan, respectively. This listing effect persists during the global financial crisis and has a negative effect on the wealth of acquiring shareholders, especially when the target countries are emerging markets. Second, greater uncertainty regarding the target countries' economic growth in cross-border M&As has a negative effect on the wealth of acquiring firms' shareholders. Third, our empirical analysis demonstrates that the listing effect is attributable to the fact that firms listed in a target country with greater uncertainty of economic growth are more directly and greatly exposed to uncertain capital markets through stock markets, than are unlisted firms. Originality/value - This study is significant in that it presents a new strategic perspective in the study of cross-border M&As by demonstrating empirically that the listing effect is attributable to the uncertainty regarding the economic development of the target firms' home countries.

• The Journal of Internal Korean Medicine
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• v.42 no.6
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• pp.1255-1268
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• 2021

Objectives: This study aimed to analyze the healthcare utilization behavior of patients visiting the department of Korean internal medicine in the Korean medicine hospital of Wonkwang University in Jeon-ju from July 2018 to June 2021. Methods: We retrospectively analyzed the medical records of 26,108 patients and sorted the data by period, month, visiting types, new or returning types, sex, and age group. IBM SPSS 26.0 and the R 4.05 'changepoint' package were used with various statistical methods, such as Independent t-test, Mann-Whitney test, Chi-square test, Simple regression analysis. The P-value was set at 0.05. Results and Conclusions: Females outnumbered males regardless of period, and the ratio of females fell after COVID-19. Regardless of visiting types, patients in their 50s, 60s, and 70s outrated any other age group. The average number of females among the returning patients decreased significantly after COVID-19, but did not in males. Outpatients under 10 and in their 10s decreased significantly after COVID-19, as did inpatients in their 40s and 60s. The average duration of hospitalization was extended significantly after COVID-19. The number of outpatients and inpatients decreased as time passed after COVID-19. We expect that the results of this study will be used as reference materials in analyzing the effects of COVID-19 on healthcare utilization.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.5
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• pp.197-202
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• 2022

IoT (Internet of Things) devices are being attacked by malware due to many security vulnerabilities, such as the use of weak IDs/passwords and unauthenticated firmware updates. However, due to the diversity of CPU architectures, it is difficult to set up a malware analysis environment and design features. In this paper, we design time series features using the byte sequence of executable files to represent independent features of CPU architectures, and analyze them using recurrent neural networks. The proposed feature is a fixed-length time series pattern extracted from the byte sequence by calculating partial entropy and applying linear interpolation. Temporary changes in the extracted feature are analyzed by RNN and LSTM. In the experiment, the IoT malware detection showed high performance, while low performance was analyzed in the malware family classification. When the entropy patterns for each malware family were compared visually, the Tsunami and Gafgyt families showed similar patterns, resulting in low performance. LSTM is more suitable than RNN for learning temporal changes in the proposed malware features.

• Korean Journal of Biological Psychiatry
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• v.29 no.2
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• pp.33-39
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• 2022

Objectives The early growth response 3 (EGR3) gene located in chromosome 8p21.3 is one of the susceptibility loci in many psychiatric disorders. EGR3 gene plays critical roles in signal transduction in the brain, which is involved in neuronal plasticity, neuronal development, learning, memory, and circadian rhythms. Recent studies have suggested EGR3 as a potential susceptibility gene for bipolar disorder (BPD). However, this requires further replication with an independent sample set. Methods To investigate the genetic role of EGR3 in Korean patients, we genotyped six single-nucleotide polymorphisms (SNPs) in the chromosome region of EGR3 in 1076 Korean BPD patients and 773 healthy control subjects. Results Among the six examined SNPs of EGR3 (rs17088531, rs1996147, rs3750192, rs35201266, rs7009708, rs1008949), SNP rs35201266, rs7009708, rs1008949 showed a significant association with BPD (p = 0.0041 for rs35201266 and BPD2, p = 0.0074 for rs1008949 and BPD, p = 0.0052 for rs1008949 and BPD1), which withstand multiple testing correction. In addition, the 'G-C-C-C' and 'G-C-G-C' haplotypes of EGR3 were overrepresented in the patients with BPD (p = 0.0055, < 0.0001, respectively) and the 'G-T-G-C' haplotype of EGR3 was underrepresented in patients with BPD (p = 0.0040). Conclusions In summary, our study supports the association of EGR3 with BPD in Korean population sample, and EGR3 could be suggested as a compelling susceptibility gene in BPD.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.1
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• pp.109-118
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• 2022

Purpose : The study to verify the effectiveness of the Soomchi combined marine healing program by analyzing the physical composition of the subjects, their blood lipids, and the effects of the program on their lung health-related variables, and heart rate variability variables. Methods : In the experiment, the Soomchi combined marine healing program was conducted for 5 hours a day, 5 days a week. on 15 participants. The results of their body composition, blood lipids, lactic acid, blood pressure, PEF, FEV1 and maximum oxygen intake were analyzed before and after the subjects completed the Soomchi program. For the statistical analysis, the mean and standard deviation (M±SD) of each variable were calculated using SPSS version 20 and an independent t-test was conducted to test for the amount of change in the participants before and after the Soomchi combined marine healing program. All significant levels were set to α=.05. As a result of the experiment Results : First, no statistically significant differences were found in the changes in body composition after the 5-day combined marine healing program was completed. Second, regarding the changes in blood component after the program was conducted, statistically significant differences were found in the lactic acid (p<.05). That is, the experimental group showed a significant decrease in lactic acid after the program whereas the control group showed a significant increase. Third, systolic blood pressure decreased significantly and while in PEF and FEV1 increased significantly in the experimental group after the program. Fourth, the LF of the control group significantly decreased after 5 days. Conclusion : After the Soomchi Lung Health Ocean Healing Program, positive physical changes were observed in the lung health variables and heart rate variability of the participants.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.1
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• pp.129-136
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• 2022

Purpose : The purpose of this study was to investigate the effect of applying intensity on the muscle activity and muscle hardness of the upper trapezius muscle in adult males when TENS (transcutaneous electrical nerve stimulation) was applied. In addition, this study intends to prepare the scientific basic data of TENS for the purpose of relaxation based on the experimental results. Methods : Eighty-seven healthy adult males participated in the experiment, and they were randomly divided into an experimental group and a control group. All subjects in this study were healthy subjects without musculoskeletal or nervous system damage. All subjects were subjects who voluntarily consented to the purpose and method of the experiment. All subjects were provided with a load by typing for 20 minutes, and muscle activity and muscle hardness of the upper trapezius muscle were measured immediately. Afterwards, TENS was given to each groups for 15 minutes, and the experimental group received stimulation at the motor threshold level, and the control group received a placebo stimulation. After stimulation, muscle activity and muscle hardness of the upper trapezius muscle were measured in the same method. The measured data were compared between groups through an independent t-test and dependent t-test. The statistical significance level was set at .05. Results : The application of TENS statistically significantly decreased the muscle activity and muscle hardness of the trapezius muscle in the experimental group, and the results showed a significant difference from the control group. Conclusion : Application of TENS significantly decreased the muscle activity and muscle stiffness of the upper trapezius muscle. The application of TENS of applying intensity that induces muscle contraction may induce relaxation by reducing the muscle activity and muscle hardness of the trapezius muscle.

• Imaging Science in Dentistry
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• v.52 no.1
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• pp.11-18
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• 2022

Purpose: This study aimed to assess incidental abnormal findings in the paranasal sinuses and anatomical variations of the ostiomeatal complex (OMC) on magnetic resonance imaging (MRI) scans. Materials and Methods: MRI scans of 616 patients (mean age, 44.0±19.4 years) were evaluated. Prior to obtaining the MRI scans, a checklist of patients' clinical symptoms was filled out after obtaining their consent. The Lund-Mackay classification was used to assess the paranasal sinuses and OMC. The prevalence of abnormal findings and their associations with patients' age, sex, and subjective symptoms were analyzed by the chi-square test, independent-sample t-test, and analysis of variance. The level of significance was set at 0.05. Results: Abnormal findings in the paranasal sinuses were detected in 32.0% of patients, with a significantly higher prevalence in males (P<0.05), but no significant association with age (P>0.05). Epithelial thickening and retention cyst were the most common abnormal findings in the paranasal sinuses. According to the Lund-Mackay classification, 93% of the study population had normal sinuses (score<4). Concha bullosa and paradoxical concha were detected in 15.3% and 3.4%, respectively, with no significant association with the presence of septal deviation or Lund-Mackay classification (P>0.05). Conclusion: Considering the relatively high prevalence of abnormal findings in the paranasal sinuses, it appears that clinical symptoms alone are not sufficient to diagnose sinusitis. A more accurate strategy would be to assess radiographic images of the paranasal sinuses and use a classification system. Sinusitis should be suspected in patients receiving a high score in this classification.

• Journal of Information Technology Applications and Management
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• v.28 no.6
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• pp.1-21
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• 2021

This study is about Augmented Reality Game (AR Game) applied to Pokemon Go, which has recently been a sensational game. We focused on and analyzed the intention for continuous use as a dependent variable. We made hypotheses through previous studies and used spatial presence, perceived interactivity, perceived pleasure, and sickness as independent variables. Immersion was set up as a mediating variable. We conducted the study using 198 data, which people who experienced AR games responded. The results were as follows. First, spatial presence and perceived pleasure were found to have a significant effect on immersion, as in previous studies. Second, the relationship between sickness and immersion, which were shown to have a negative relationship in previous studies, we found that variables had a positive relationship unlike previous studies and rejected the hypothesis. Third, perceived interactivity, which is one of the crucial variables to affect the intention for continuous use, we found not to have a significant relationship among perceived interactivity, immersion, and the intention for continuous use. This result is opposite from previous studies, and further research on this issue is expected. We conducted this study with an individual user's view on immersion and the intention for continuous use rather than focusing on technical or political topics. Besides, this study has a significance that drew different results from previous studies and explored people who relish AR games with the characteristics of personal variables.

• Restorative Dentistry and Endodontics
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• v.48 no.2
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• pp.15.1-15.7
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• 2023

Objectives: This study evaluated the efficiency of WaveOne Primary files (Dentsply Sirona) for removing root canal fillings with 2 types of movement: reciprocating (RCP) and continuous counterclockwise rotation (CCR). Materials and Methods: Twenty mandibular incisors were prepared with a RCP instrument (25.08) and filled using the Tagger hybrid obturation technique. The teeth were retreated with a WaveOne Primary file and randomly allocated to 2 experimental retreatment groups (n = 10) according to movement type: RCP and CCR. The root canals were emptied of filling material in the first 3 steps of insertion, until reaching the working length. The timing of retreatment and procedure errors were recorded for all samples. The specimens were scanned before and after the retreatment procedure with micro-computed tomography to calculate the percentage and volume (mm³) of the residual filling material. The results were statistically evaluated using paired and independent t-tests, with a significance level set at 5%. Results: No significant difference was found in the timing of filling removal between the groups, with a mean of 322 seconds (RCP) and 327 seconds (CCR) (p < 0.05). There were 6 instrument fractures: 1 in a RCP motion file and 5 in continuous rotation files. The volumes of residual filling material were similar (9.94% for RCP and 15.94% for CCR; p > 0.05). Conclusions: The WaveOne Primary files used in retreatment performed similarly in both RCP and CCR movements. Neither movement type completely removed the obturation material, but the RCP movement provided greater safety.