• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.571-578
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• 2006

Research using multiple shake tables present new and unique challenges in controls. Typical single shake table tests with large specimens must cope with significant specimen force feedback that can increase tracking error due to specimen gain, damping, and non-linearity. Multiple shaking tables with distributed specimens can produce cross-coupling forces due to inertial and response effects and forces due to static differential displacements. Although many various control architectures exist, basic simplified techniques can yield excellent results without risk to control stability. Off-line simulation techniques can also prove invaluable for studying system response before the real system is operated.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.33 no.1
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• pp.13-19
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• 2022

Vocal fold leukoplakia poses a challenge to otolaryngologists due to its various spectrum of pathologic diagnosis. The degree of dysplasia is associated with malignancy risk and the new 2017 WHO classification system changed from the 3-tier system to a 2-tier system consisting of low and high grades. Infections including candidiasis, cryptococcosis, and tuberculosis should also be included in the differential diagnosis. Efforts have been made to evaluate risks using endoscopic technologies such as narrow band imaging, and surgery is essential for histopathological diagnosis. Regarding management, it is important to make an accurate diagnosis and find a balance between oncologic safety and functional outcome.

• The Journal of Korea Robotics Society
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• v.17 no.1
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• pp.32-39
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• 2022

Since the mobile platform and the manipulator mounted on it move at the same time in a mobile manipulator, the risk of mutual collision increases. Most of the studies on collision avoidance of mobile manipulators cannot be applied to differential drive type mobile platforms or the end-effector tends to deviate from the desired trajectory for collision avoidance. In this study, a collision avoidance algorithm based on null space projection (CANS) that solves these two problems is proposed. To this end, a modified repulsive force that overcomes the non-holonomic constraints of a mobile platform is generated by adding a virtual repulsive force in the direction of its instantaneous velocity. And by converting this repulsive force into a repulsive velocity and applying it to the null space, the end-effector of the robot avoids a collision while moving along its original trajectory. The proposed CANS algorithm showed excellent performance through self-collision avoidance tests and door opening tests.

• Asian Journal for Public Opinion Research
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• v.10 no.2
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• pp.76-101
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• 2022

Despite the increasing use of digital media and their powerful impact on risk management during recent outbreaks of emerging infectious diseases, the question of how digital media exposure influences preventive behaviors has not been fully explained. Using the appraisal tendency framework and protection motivation theory as theoretical frameworks, we theorized the affective and cognitive mechanisms under which the differential roles of three negative emotions (fear, anger, worry) on two cognitive appraisals (perceived threat and perceived efficacy) were examined. Based on data collected from a survey of 1,500 South Koreans during the COVID-19 pandemic, we found that while worry and anger increased perceived efficacy, fear reduced perceived efficacy. The results also showed that although exposure to COVID-19 information via digital formats increased preventive behavioral intention in general, digital media use for COVID-19 information had a negative influence on preventive behavioral intention through the sequential mediation of fear and perceived efficacy.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.264-267
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• 2022

Recently, federated learning (FL) has increased prominence as a viable approach for enhancing user privacy and data security by allowing collaborative multi-party model learning without exchanging sensitive data. Despite this, most present FL systems still depend on a centralized aggregator to generate a global model by gathering all submitted models from users, which could expose user privacy and the risk of various threats from malicious users. To solve these issues, we suggested a safe FL framework that employs differential privacy to counter membership inference attacks during the collaborative FL model training process and empowers blockchain to replace the centralized aggregator server.

• Research in Community and Public Health Nursing
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• v.31 no.1
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• pp.13-23
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• 2020

Purpose: This study explored the contribution of social support resources to the explanation of socioeconomic inequalities in depressive symptoms of older Korean men and women. Methods: Data were derived from Living Profiles of Older People Survey (LPOPS), which comprises a nationally representative sample of non-institutionalized Korean older adults living in the community. The data were analyzed by using multiple logistic regression. The sample consisted of 4,046 men and 6,036 women aged ≥65 years. The Korean version of the Geriatric Depression Scale-Short form (SGDS-K) was employed as an outcome variable. Results: Compared to the older men and women who were in higher socioeconomic status, those in lower socioeconomic status had significantly higher risk of depressive symptoms after adjusting for other covariates. When social support resources were individually included in the base model, each factor contributed to inequalities in depressive symptoms. Social networks explained about 20% of the differential impact of education and 10% to 15% of the differential impact of household income for depressive symptoms in men. Among women, it mitigated 23.6% to 39.0% of education and household income inequalities for depressive symptoms. Social participation contributed to buffer depressive symptom inequalities of 24.0% to 46.3% among men and those of 11.7% to 45.3% among women. Conclusion: Our findings suggest community care nurses acknowledge the value of social support resources to alleviate socioeconomic inequality in depressive symptoms among older men and women.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2007.04a
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• pp.147-153
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• 2007

Central to developing new treatment strategies for late onset sporadic Parkinson's disease (PD) and early onset familial PD is resolving the enigma of the specific vulnerability exhibited by substantia nigra dopamine (DA) neurons despite multiple risk factors. Neuropathological evidence from both human and experimental models of PD firmly supports a significant role for oxidative stress (OS) and mitochondrial dysfunction in the death of nigral DA neurons. Largely unknown are the genes underlying selective susceptibility of nigral DA neuron to OS and mitochondrial dysfunction and how they effect nigral DA cell death. To overcome the paucity of nigral DA neurons as well as the dilution effect of non-DA cells in brain tissues, we have developed wild type DA cell line model, SN4741 and mutant DJ-1 (-/-) DA cells, appropriate for microarray analysis and differential mitochondrial proteomics. Mutations in the DJ-1 gene (PARK7), localized in cytoplasm and mitochondria, cause autosomal recessive early onset PD. Through microarray analysis using SN4741 cells followed by validation tests, we have identified a novel phylogenically conserved neuroprotective gene, Oxi-a, which is specifically expressed in DA neurons. The knockdown of the gene dramatically increased vulnerability to as. Importantly as down-regulated the expression level of the gene and recovery of its expression via transient transfection exerted significant neuroprotection against as insult. We also have identified altered expression of mitochondrial proteins and other familial PD genes in DJ-1 (-/-) mutant cells by differential mitochondrial proteomics. In DJ-1 (-/-) cells the knockdown of the other familial PD genes (Parkin and PINK1) dramatically increased susceptibility to as. Thus, further functional characterization of the Oxi-$\alpha$ gene family and the mitochondrial alteration in the DJ-1 (-/-) cell model will provide the rationale for the neuroprotective therapy against both sporadic and familial PD.

• Korea journal of population studies
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• v.34 no.1
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• pp.179-198
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• 2011

The purpose of this study was to examine relationships between chronic diseases, age, and education in Korea. Logistic regression techniques were used to analyze data from the Korean Longitudinal Study of Ageing (KLoSA), which is a nationally representative sample of Koreans aged 45 years and older. The findings show that probability of having chronic diseases increased with age up to about 74; however, it was reduced for respondents aged 74 years or older. Associations between age and chronic diseases were also differential by education. Less educated Koreans tended to have chronic diseases earlier in their lifetime; however, they were likely to have chronic diseases later in life less than more educated counterparts. The findings suggest that individuals with fewer years of education are at an increased risk of developing chronic diseases earlier in their lifetimes, thereby, leading to a higher rate of mortality at younger ages.

• Journal of Auto-vehicle Safety Association
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• v.5 no.2
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• pp.24-31
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• 2013

This paper describes a coordinated control algorithm for rear-side collision avoidance. In order to assist driver actively and increase driver's safety, the proposed coordinated control algorithm is designed to combine lateral control using a steering torque overlay by Motor Driven Power Steering (MDPS) and differential braking by Vehicle Stability Control (VSC). The main objective of a combined control strategy is twofold. The one is to prevent the collision between the subject vehicle and approaching vehicle in the adjacent lanes. The other is to limit actuator's control inputs and vehicle dynamics to safe values for the assurance of the driver's comfort. In order to achieve these goals, the Lyapunov theory and LMI optimization methods has been employed. The proposed coordinated control algorithm for rear-side collision avoidance has been evaluated via simulation using CarSim and MATLAB/Simulink.

• Journal of Radiation Protection and Research
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• v.41 no.4
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• pp.402-408
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• 2016

Background: Ascertainment bias are common in epidemiologic studies to assess the association between thyroid cancer risk and living near nuclear power plants because many thyroid cancers are diagnosed by chance through health examination. We surveyed the ultra sonography (USG) examination history and conducted thyroid and breast USG in residents living near nuclear power plants. Materials and Methods: The study population comprised 2,421 residents living near nuclear power plants in Korea. Information on demographic characteristics, including diagnostic examination history, was collected by interview using questionnaires. USG examination was conducted to evaluate the presence of thyroid nodules and breast lesion. Study participants were divided into 3 groups according to the distance of their respective villages from a nuclear power plant. The proportions of USG examination history and prevalence of thyroid nodules and breast lesions were compared between groups. Results and Discussion: Examination histories of thyroid USG were 23.1%, 13.7%, and 10.5% in men and 31.3%, 26.7%, 18.3% in women in the short, intermediate, and long distance groups, respectively. There were significant inverse associations between thyroid USG history and the distance from nuclear power plants (P for trend = 0.001 for men and 0.017 for women). However, there was no association between the distance of villages from nuclear power plants and prevalence of thyroid nodules. Conclusion: Our results suggest that there may be an ascertainment bias in population-based studies examining the harmful effects of NPPs examination and researchers should pay attention to ascertainment bias resulted from differential health examination. Correction for ascertainment bias, active follow-up and examination for all study population to remove differential health examination is needed.