• Korean Journal of Clinical Laboratory Science
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• v.54 no.4
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• pp.249-255
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• 2022

Alzheimer's disease (AD) represents a major public health concern and has been identified as a research priority. Clinical research evidence supports that the core cerebrospinal fluid (CSF) biomarkers for AD, including amyloid-β (Aβ42), total tau (T-tau), and phosphorylated tau (P-tau), reflect key elements of AD pathophysiology. Nevertheless, advances in the clinical identification of new indicators will be critical not only for the discovery of sensitive, specific, and reliable biomarkers of preclinical AD pathology, but also for the development of tests that facilitate the early detection and differential diagnosis of dementia and disease progression monitoring. The early detection of AD in its presymptomatic stages would represent a great opportunity for earlier therapeutic intervention. The chance of successful treatment would be increased since interventions would be performed before extensive synaptic damage and neuronal loss would have occurred. In this study, the importance of developing an early diagnostic method using cognitive decline biomarkers that can discriminate between normal, mild cognitive impairment (MCI), and AD preclinical stages has been emphasized.

• Journal of Korean Society of Forest Science
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• v.112 no.3
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• pp.340-351
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• 2023

Landslides are major natural geological hazards that cause enormous property damage and human casualties annually. The vulnerability of mountainous areas to landslides is further exacerbated by the impacts of climate change. Soil depth is a crucial parameter in landslide and debris flow analysis, and plays an important role in the evaluation of watershed hydrological processes that affect slope stability. An accurate method of estimating soil depth is to directly investigate the soil strata in the field. However, this requires significant amounts of time and money; thus, numerous models for predicting soil depth have been proposed. However, they still have limitations in terms of practicality and accuracy. In this study, 71 seismic survey results were collected from domestic mountainous areas to estimate soil depth on hill slopes. Soil depth was estimated on the basis of a shear wave velocity of 700 m/s, and a database was established for slope angle, elevation, and soil depth. Consequently, the statistical characteristics of soil depth were analyzed, and the correlations between slope angle and soil depth, and between elevation and soil depth were investigated. Moreover, various soil depth prediction models based on slope angle were investigated, and corrected linear and exponential soil depth prediction models were proposed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.4
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• pp.273-282
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• 2023

Probabilistic safety assessment (PSA) has been widely used to evaluate the seismic risk of nuclear power plants (NPPs). However, studies on seismic PSA for process plants, such as gas plants, oil refineries, and chemical plants, have been scarce. This is because the major disasters to which these process plants are vulnerable include explosions, fires, and release (or dispersion) of toxic chemicals. However, seismic PSA is essential for the plants located in regions with significant earthquake risks. Seismic PSA entails probabilistic seismic hazard analysis (PSHA), event tree analysis (ETA), fault tree analysis (FTA), and fragility analysis for the structures and essential equipment items. Among those analyses, ETA can depict the accident sequence for core damage, which is the worst disaster and top event concerning NPPs. However, there is no general top event with regard to process plants. Therefore, PSA cannot be directly applied to process plants. Moreover, there is a paucity of studies on developing fragility curves for various equipment. This paper introduces PSA for gas plants based on FTA, which is then transformed into Bayesian network, that is, a probabilistic graph model that can aid risk-informed decision-making. Finally, the proposed method is applied to a gas plant, and several decision-making cases are demonstrated.

• Journal of Environmental Impact Assessment
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• v.32 no.4
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• pp.242-250
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• 2023

The continuity of urban space is being destroyed by disorderly high-rise development caused by reckless development, and the resulting deterioration of urban landscape is emerging as a major problem. Disordered high-rise development is adversely affecting the urban environment, such as depriving residents of the basic rights of view and sunlight and privatizing the scenery that urban residents should enjoy together. In order to create a continuous urban landscape, indiscriminate high-rise development is restricted and compensation for the affected areas is needed. Various regulations have been carried out to this end, but it is difficult to overcome the pressure and damage to high-rise development by regulations alone. Accordingly, discussions have been underway to introduce a compensation system. Among them, discussions on the introduction of a 'Transfer of Development Right' (TDR) in which land ownership and development rights are separated and compensated for development rights have been drawing attention. However, in Korea, it is difficult to introduce the system due to various problems related to the separation of development rights. In order to overcome the limitations of the introduction of TDR, this paper analyzed the concepts and characteristics of 'Real Estate Investment Trusts' (REITs) and presented a policy model for the development right transfer system incorporating REITs for effective landscape management.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.358-360
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• 2022

Modern society is developing rapidly and technologies that provide convenience in living are developing day by day. On the other hand, the development of cyber attacks that threaten cybersecurity is developing faster, and it still adversely affects the industrial environment, and industrial damage is steadily occurring every year. Industrial security is an activity that safely protects major assets or technologies of companies and organizations from these attacks. Therefore, it is a situation that requires professional manpower for security. Currently, the manpower situation for security is staffed, but knowledge of the understanding and concept of industrial security jobs is insufficient. In other words, there is a lack of professional manpower for industrial security. It is the NCS that came out to solve this problem. NCS is the state standardized ability (knowledge, attitude, skills, etc.) necessary to perform duties in the industrial field. NCS can systematically design the curriculum using NCS as well as help in hiring personnel, and NCS can be applied to the national qualification system. However, in the field of industrial security, NCS has not yet been developed and is still having difficulties in hiring personnel and curriculum. Although the NCS system in the field of industrial security has not been developed, this paper proposes the industrial security NCS to solve the problem of hiring professionals later and to help the field of industrial security NCS to be established later.

• Journal of Navigation and Port Research
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• v.47 no.1
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• pp.37-48
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• 2023

Recently, the increase of international trade volume is leading to risk exposure and safety accidents in the port terminal industry. In addition, as Serious Disaster Punishment Act came into effect on January, 2021, various guidelines and laws to protect safety and life in port terminals are being enacted. However, despite these efforts, medium-to-large safety accidents in the port terminal industry have occurred. According to the Korea Occupational Safety and Health Agency, from 2016 to 2019, the number of casualties in the port handling industry increased by 4.2%. To build some effective follow-up management of port accidents and preparation of related safety laws/systems, a risk analysis in consideration of causes and damage of accidents should be conducted. Therefore, in this study, major risk factors and preventive measures were derived by conducting risk assessment based on 1,039 cases of port terminal accidents collected by the Korea Occupational Safety and Health Agency for five years. Priorities for preventive measures were then determined through IPA analysis, Borich needs analysis, and The Locus For Focus analysis.

• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.542-549
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• 2021

Citrus leafminer (Phyllocnistis citrella) is an economically important pest in citrus orchards. This study was conducted to elucidate the over-wintering stage of P. citrella through experiments on the survival rate of P. citrella at low temperatures and field investigations during the winter season. There was a significant difference in the survival period depending upon the over-wintering stage of P. citrella at low temperatures, and the adults survived longer than the pupae. Evaluation of the survival period after inoculating citrus orchards with P. citrella adults and pupae showed that only the adults survived until mid-March of the following year, but all pupae died in January. This suggests that considering the fact that the germination of spring shoots in Jeju generally begins in mid-March, over-wintering adults are likely to form an early population the next year. However, pupae may not contribute to the formation of the initial population in the early season after wintering in fall shoots that are prone to freezing damage in winter because P. citrella could only survive in pupal chambers formed in fall shoots. Therefore, these results suggest that P. citrella adults that emerge in late autumn can over-winter in citrus orchards in Jeju, Korea.

• Journal of the Korean Geotechnical Society
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• v.23 no.3
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• pp.25-40
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• 2007

Excessive earth pressure is one of the major mechanical factors in the deformation and damage of Cut-and-Cover Tunnel lining in shallow tunnels and portals of mountain tunnels (Kim, 2000). Excessive earth pressure may be attributed to insufficient compaction and consolidation of backfill material due to self-weight, precipitation and vibration caused by traffic (Komiya et al., 2000; Taylor et al., 1984; Yoo, 1997). Even though there were a lot of tests performed to determine the earth pressure acting on the tunnel lining, unfortunately there were almost no case histories of studies performed to determine remedial measures that reduce differential settlement and excessive earth pressure. In this study the installation of geotextile mat was selected to reduce the differential settlement and excessive earth pressure acting on the cut-and-cover tunnel lining. In order to determine settlement and earth pressure reduction effect (reinforcement effect) of geotextile mat reinforcement, laboratory tunnel model tests were performed. This study was limited to the modeling of rigid circular cut-and-cover tunnel constructed at a depth of $1.0D\sim1.5D$ in loose sandy ground and subjected to a vibration frequency of 100 Hz. Model tests with varying soil cover, mat reinforcement scheme and slope roughness were performed to determine the most effective mat reinforcement scheme. Slope roughness was adjusted by attaching sandpaper #100, #400 and acetate on the cut slope surface. Mat reinforcement effect of each mat reinforcement scheme were presented by the comparison of earth pressure obtained from the unreinforced and mat reinforced model tests. Soil settlement reduction was analyzed and presented using the Picture Analysis Method (Park, 2003).

• Journal of the Korean Institute of Gas
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• v.27 no.2
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• pp.7-15
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• 2023

The electric submersible pump (ESP) has been operating in production wells around the world because of its high applicability and operational efficiency among artificial lift techniques. When operating an ESP in a reservoir, variables such as temperature, pressure, gas/oil ratio, and flow rate are factors that affect ESP performance. In particular, free gas in the production fluid is a major factor that reduces the life and operational efficiency of ESP. This study presents the flow loop system which can implement the performance and damage tests of ESP considering field operating conditions to quantitatively analyze the variables that affect ESP performance. The developed apparatus in an integrated system that can diagnose the failure and causes of ESP, and detect leak of tubing by linking ESP and tubing as one system. In this study, the flow conditions for stable operation of ESP were identified through single phase and two phase flow experiments related to evaluation for the performance of ESP. The results provide the basic data to develop the failure prediction and diagnosis program of ESP, and are expected to be used for real-time monitoring for optimal operating conditions and failure diagnosis for ESP operation.

• 한국체육학회지인문사회과학편
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• v.55 no.3
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• pp.543-551
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• 2016

The study was aimed at investigating the relationship between biomechanical properties of cervical muscles and smartphone addiction score in fifty healthy males using smartphone more than 60 minutes each day. The usage of smartphone was evaluated by smartphone addiction survey developed from Korean International Society Agency. Biomechanical properties of three major cervical muscles; splenius capitis, sternocleidomastoid and upper trapezius, were measured by Myoton, and conducted five parameters; frequency, decrement, stiffness, creep, and relaxation time. As results, all parameters had less than 2% of coefficient of variation(CV) between measurement intervals. Also, intra-class correlation coefficient(ICC) indicated a high reliability(ICC>.9, p<.01). Moreover, the smartphone addiction score was significantly different in frequency(r=.353, p<.05) and stiffness(r=.346, p<.05) on upper trapezius; in addition, in decrement(r=-.284, p<.05) and creep(r=.288, p<.05) on sternocleidomastoid. Especially, splenius capitis was closely related with the overuse of smartphone(frequency, r=-.368, p<.01; decrement, r=-.405, p<.01; stiffness, r=-.424, p<.01). In conclusion, this study implied that the overuse of smartphone is significantly related with the damage of cervical muscles, cervical pain, and headache; furthermore, Myoton can be used as an effective device to assess mechanical properties of cervical muscles.