• Journal of Advanced Navigation Technology
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• v.26 no.4
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• pp.185-194
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• 2022

Avionics equipment requires various environmental conditions and performance during development, and as a countermeasure against such development risk, the worst-case circuit analysis(WCCA) is applied to predict perform preliminary performance analysis. WCCA calculates the maximum and minimum values by combining the parameter values of the relevant circuit after deriving the parameter values in consideration of the aging of the temperature and operating period at the component level. In this paper, the necessary matters for WCCA application are described. Chapter 2 describes the differences and characteristics of the WCCA techniques EVA, RSS, and Monte Carlo.Chapter 3 introduces the analysis process through the example circuit to introduce the actual analysis procedure. Chapter 4 describes the method of selecting an analysis technique for each condition of the analysis target. As a result of applying the procedures and analysis methods introduced in this paper when open, it was confirmed that preliminary performance analysis and part optimization design verification are possible.

• Tuberculosis and Respiratory Diseases
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• v.84 no.3
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• pp.188-199
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• 2021

Background: Chronic obstructive pulmonary disease (COPD) is a common chronic respiratory disease with increased prevalence in the elderly. Telomeres are repetitive DNA sequences found at the end of the chromosome, which progressively shorten as cells divide. Telomere length is known to be a molecular marker of aging. This study aimed to assess the relationship between telomere length and the risk of COPD, lung function, respiratory symptoms, and emphysema index in Chronic Obstructive Pulmonary Disease in Dusty Areas (CODA) cohort. Methods: We extracted DNA from the peripheral blood samples of 446 participants, including 285 COPD patients and 161 control participants. We measured absolute telomere length using quantitative real-time polymerase chain reaction. All participants underwent spirometry and quantitative computed tomography scan. Questionnaires assessing respiratory symptoms and the COPD Assessment Test was filled by all the participants. Results: The mean age of participants at the baseline visit was 72.5±7.1 years. Males accounted for 72% (321 participants) of the all participants. The mean telomere length was lower in the COPD group compared to the non-COPD group (COPD, 16.81±13.90 kb; non-COPD, 21.97±14.43 kb). In COPD patients, 112 (75.7%) were distributed as tertile 1 (shortest), 91 (61.1%) as tertile 2 and 82 (55%) as tertile 3 (longest). We did not find significant associations between telomere length and lung function, exacerbation, airway wall thickness, and emphysema index after adjusting for sex, age, and smoking status. Conclusion: In this study, the relationship between various COPD phenotypes and telomere length was analyzed, but no significant statistical associations were shown.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.131-142
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• 2021

For old piers constructed when seismic design code had not been developed, lap splices usually exist in plastic hinge region. Corrosion of rebars causes decreasement in cross-sectional area of rebar and deterioration of lap-splice behaviour, thereby reducing the seismic performance of the old piers. In this research, according to these characteristics of old piers, test specimens are designed and manufactured considering rebar corrosion, lap splice, seismic design details, and seismic reinforcement. These effects are investigated through experiments. As a result of these experiment, rebar corrosion as well as lap splice reduces displacement ductility. When seismic design details or steel-plate reinforcement are applied, sufficient displacement ductility is expressed. For non-seismically designed specimens, loosening of the lap splice of transverse rebars caused buckling of longitudinal rebars and crushing of core concrete in plastic hinge region . For seismically designed specimen, area-reducing and untying of transverse rebars due to corrosion of rebars caused buckling of longitudinal rebars and crushing of core concrete.

• The Korea Journal of Herbology
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• v.32 no.5
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• pp.13-18
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• 2017

Objectives : The aim of this study is to investigate anti-inflammation of Leonurus sibiricus methanol extract against UVB-damage in fibroblast. The skin is continuously exposed to damage from environmental stresses. UV radiation causes a variety of biological effects especially on the skin, including inflammation and photoaging. Methods : In this study, we tried to search for Leonurus sibiricus which exhibit protective activities against UVB-induced cytotoxicity and oxidative cell death, NO and $PGE_2$ production. HS68 cells were exposed to UVB ($120mJ/cm^2$) and treated with various concentrations (0, 0.25, 0.5, 1, 2, 4, $8mg/m{\ell}$) of Leonurus sibiricus methanol extract for additional 24 h. Intracellular reactive oxygen species (ROS) levels generated by UV radiation were detected using a spectrofluorometer after DCF-DA staining. Also, HS68 cells were irradiated with UVB and then treated with Leonurus sibiricus methanol extract for 12 h. The lipid peroxidation was assayed by measuring the levels of 8-isoprostane secreted into the culture medium. Results : UVB-induced cytotoxicity and cell death were effectively suppressed by treatment of Leonurus sibiricus aqueous methanol extracts. Oxidative cell damage was mediated $PGE_2$ in UVB-induced HS68 fibroblast cell, which was significantly inhibited by treatment with Leonurus sibiricus extracts. Also, the protective effect of these extract seemed to be mediated by inhibited intracellular ROS generation and lipid peroxidation in dose-dependent manner. Conclusion : These results suggest that Leonurus sibiricus aqueous methanol extracts may have anti-aging effects new functional materials against oxidative UVB stress-mediated skin damages.

• Structural Engineering and Mechanics
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• v.81 no.5
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• pp.617-631
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• 2022

In this paper the viscoelastic responses of four experimental steel-concrete composite beams subjected to highly variable environmental conditions are investigated by means of a finite element (FE) model. Concrete specimens submitted to stepped stress changes are also evaluated to validate the current formulations. Here, two well-known approaches commonly used to solve the viscoelastic constitutive relationship for concrete are employed. The first approach directly solves the integral-type form of the constitutive equation at the macroscopic level, in which aging is included by updating material properties. The second approach is postulated from a rate-type law based on an age-independent Generalized Kelvin rheological model together with Solidification Theory, using a micromechanical based approach. Thus, conceptually both approaches include concrete hardening in two different manners. The aim of this work is to compare and analyze the numerical prediction in terms of long-term deflections of the studied specimens according to both approaches. To accomplish this goal, the performance of several well-known model codes for concrete creep and shrinkage such as ACI 209, CEB-MC90, CEB-MC99, B3, GL 2000 and FIB-2010 are evaluated by means of statistical bias indicators. It is shown that both approaches with minor differences acceptably match the long-term experimental deflection and are able to capture complex oscillatory responses due to variable temperature and relative humidity. Nevertheless, the use of an age-independent scheme as proposed by Solidification Theory may be computationally more advantageous.

• 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 Korean Society of Rural Planning
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• v.28 no.3
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• pp.111-125
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• 2022

Korea's rapid urbanization caused problems, such as destruction of the rural environment, loss of traditional culture and dissolution of communities, as the continuous outflow of the population from rural areas, aging and consequent labor shortages and deterioration of the living environment were connected like a vicious cycle. In order to solve the problems of rural areas and overcome their vulnerabilities, the ultimate goal is to find a way to reintroduce the population to the rural areas. In order to be reborn as a space with rural characteristics and pluralistic functions and various potentials in a space under threat of underdevelopment and extinction, the pushing factor from rural areas is improved, and the population inflow factor to the rural areas is improved to enhance rural attractiveness, focusing on creativity among the 4Cs of New Ruralism: Conservation, Cultivation, Community, Creativity. A case study of 'Creative space in rural areas' was studied and considered. In-depth interviews were conducted with four key stakeholders, and the research results were analyzed focusing on the grounded theory method to draw implications from the background of Gurye Natural Dream Park, characteristics that can be viewed as creative spaces, and examples of creative space creation in rural areas. The 'Creative space in rural areas' is a space that can solve the current issues and problems of rural areas. In the case of Gurye Natural Dream Park, the young population of Gurye is increasing through job creation, provision of living and cultural service facilities, and improvement of the education and medical environment. In this study, the existing rural problem-solving process in this process was viewed as creativity in rural areas.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.2
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• pp.355-360
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• 2023

Fire is a disaster that causes irreversible damage to many people due to personal injury and property damage. Various fire detection equipments are installed around us to detect and cope with it quickly. However, due to various problems such as artificial, environmental, and aging, fire detection equipment is activated even though it is not a actual fire, and there are many problems such as delaying the support to the necessary fire scene. In this paper, we analyze the non-fire alarm of the fire detection equipment and propose a system that enables the field staff to check the scene situation through the video as a way to prevent the mobilization due to the misinformation by checking the fire. The purpose of the present invention is to stably cope with a disaster by suggesting a customized automatic guidance system which induces a rapid evacuation by sending an evacuation guidance notification to a range of a fire occurrence neighboring area, and supports a rapid and accurate processing by a rapid dispatch of a firefighter, rather than a wide range of guidance such as an existing emergency disaster guidance letter when it is determined to be an actual fire through the confirmation procedure.

• Structural Monitoring and Maintenance
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• v.10 no.1
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• pp.25-42
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• 2023

Despite the significance of ports as critical economic infrastructure, the berth facilities usually deteriorate due to heavy loading, unloading, aging, environmental weather conditions, marine growths, and lack of efficient maintenance management. Marine berths require proactive maintenance management to limit deterioration and defects as no berth facility is maintenance-free. Thus, delay in carrying out maintenance work for the marine berths can be devastating to the operational process involving ship entry, loading, and unloading operations. The aim of this research is to coordinate both operations work, and maintenance works that take place inside the berth of a local industrial port in Saudi Arabia, by developing a novel framework that integrates both works without affecting the efficiency and functionality of the berth. The study focused on defining the operational process of the port and identifying the elements with direct and indirect effects. In addition to determining the priority for the entry of ships inside the berth, it also identified the factors involved in designing a framework that included maintenance work as a component of the monthly berth occupancy schedule. By applying a mathematical model, a framework was established, which includes all the important elements of the process. As a result of the mathematical method formulation process, a database was designed that organizes and coordinates the operations of all berths within the port. This creates time to carry out the required maintenance work monthly as well as ease of coordination with the contractors responsible for the implementation of those works.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.2
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• pp.219-227
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• 2022

In Korea, as the aging phenomenon accelerates, the problem of traffic accidents related to the elderly is continuously emerging. Efforts to improve this are being implemented, but unfortunately the results of these effects are not clear. Therefore, in this study, the effect of traffic characteristics and incentive policies on the return of driver's licenses of elderly drivers was reviewed. As a result of the analysis, it was confirmed that the intention to return the driver's license was low in the case of men, older people, those with low dependence on public transportation, those who undertook long driving hours, and those who took frequent trips. On the other hand, financial incentives were found to play a positive role with regard to the intention to return the driver's license. However, the effect is expected to be insignificant for those with a low intention to return the driver's license. As a result, under the current policy, it is predicted that there is a limit to improving the social problems caused by elderly drivers, meaning that it is necessary to review approaches that induce the return of their driver's licenses.