• Journal of the Korean Society for Railway
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• v.17 no.4
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• pp.260-269
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• 2014

Transition tracks are an alternative for enhancing the long-term serviceability and durability of concrete track components in railway bridges. The goal of this paper is to investigate the structural behavior for transition track systems of railway bridge deck ends. In this study, the structural behavior of transition tracks such as the variations in static, dynamic, and fatigue behaviors and dynamic properties (natural frequency and damping ratio) are assessed and compared through performing loading tests and finite element analyses using actual vehicle impact loadings. As a result, it is found that the structural behavior of the transition track system is expected to satisfy the actual vehicle impact loading, and the variation in the neutral axis and dynamic characteristics are not affected by the fatigue loading. Therefore, it is inferred that the structural capacity and long-term durability of the transition track system is proven.

• Journal of the Korean Geotechnical Society
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• v.23 no.10
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• pp.151-161
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• 2007

EPS provides a superb self-sufficient stability. Studies on the process of EPS construction method focus on the inchoate phase of general construction, which is increasingly applied to construction sites throughout the world. Unfortunately, there has been little study on the durability and long-term soil behavior involving EPS materials. In this study, the boring, in-site and laboratory tests were conducted to examine the long-term soil behavior in the back-filling of alternating behind the side to which EPS was applied. And results of finite element analysis considering various test results and the soil behavior data measured during the construction show that EPS construction method is a superb process that relieves the load and consequently reduces the settlement, alleviates the stress on the abutment, and prevents lateral flow.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.105-112
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• 1999

In recent the superior economic benefits and the convenience of installation increased the use of geosynthetics, especially geogrids with the effects of high tensile strength. In this study, various tests were conducted to determine the physical and chemical properties of geogrids which contains durability under various critical conditions, creep behavior and the stability for installation damage in fields. With analysis of test results, the partial and total safety factors were determined and presented the long term design strength of flexible geogrids.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.579-582
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• 1999

This paper represents the results of experiments designed to investigate the time-dependent response of concrete and steel tube in circular concrete-filled steel tubes, as are deployed extensively in high-rise building construction. The experiments were performed for creep of concrete and CFT column specimens with three loading cases. The creep coefficient and specific creep(unit creep) obtained from the test results were used for estimating and comparing the time-dependent response of each case. From these analyses, it is show that CFT-column has many merits for long-term behavior.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.611-616
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• 2000

Numerical studies were carried out to investigate the long-term behavior of late plates in basement, subjected to combined in-plane compressive and transverse loads. For the numerical studies, a computer program of nonlinear finite element analysis was modified by adding function of creep and shrinkage analysis. This numerical method was verified by comparison with the existing experiments. Parametric studies were performed to investigate the strength variations of flat plates with three parameters; 1) loading sequence of floor load, compression and time 2) uniaxial an biaxial compression and 3) the ratio of dead to live load.

• Journal of Korean Academy of Nursing
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• v.42 no.4
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• pp.466-476
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• 2012

Purpose: The purpose of this study was to explore characteristics of eating behavior according to level of functional status of elders with dementia (EWD), and to examine feeding time, change in food intake and body mass index (BMI) according to eating behavior. Methods: Participants were 149 EWD residing in long-term care facilities located in Seoul or Gyeonggi province and evaluated using the Mini-Mental State Exam-Korean version, Korean version-Activities of Daily Living, and Eating Behavior Scale (EBS). Feeding time, change in food intake, and BMI were also measured. Data were analyzed using SPSS 17.0, specifically descriptive statistics, ANOVA, and Chi-square test. Results: Participants' mean EBS score was $10.43{\pm}6.01$ and half of them (54.4%) needed moderate or total assistance while eating. The EBS score was significantly lower for elders with severe dementia compared to those with mild or moderate dementia; and elders with severe ADL dependence compared to those with mild or moderate ADL dependence. Lower EBS scores were related to longer feeding time, a greater the rate of participants with decreased food intake and 'underweight' BMI. Conclusion: Nursing intervention programs which are designed for EWD are needed to maintain functional eating skills and prevent negative consequences in this population.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1630-1643
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• 2023

The correct situation awareness (SA) of operators is important for managing nuclear power plants (NPPs), particularly in accident-related situations. Among the three levels of SA suggested by Ensley, Level 3 SA (i.e., projection of the future status of the situation) is challenging because of the complexity of NPPs as well as the uncertainty of accidents. Hence, several prediction methods using artificial intelligence techniques have been proposed to assist operators in accident prediction. However, these methods only predict short-term plant status (e.g., the status after a few minutes) and do not provide information regarding the uncertainty associated with the prediction. This paper proposes an algorithm that can predict the multivariate and long-term behavior of plant parameters for 2 h with 120 steps and provide the uncertainty of the prediction. The algorithm applies bidirectional long short-term memory and an attention mechanism, which enable the algorithm to predict the precise long-term trends of the parameters with high prediction accuracy. A conditional variational autoencoder was used to provide uncertainty information about the network prediction. The algorithm was trained, optimized, and validated using a compact nuclear simulator for a Westinghouse 900 MWe NPP.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.477-479
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• 2018

This study was carried out to utilize LSTM(Long Short-Term Memory) technique which is one kind of artificial neural network. Among the 27 types of motion data released by the UTD(University of Texas at Dallas), 3-axis acceleration and angular velocity data were applied to the basic LSTM and Deep Residual Bidir-LSTM techniques to classify the behavior.

• Health Policy and Management
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• v.23 no.1
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• pp.90-100
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• 2013

Background: This study examined the relationships of dementia, stroke, and combined multimorbidity with long-term care utilizations among older people in South Korea. Methods: A nationally representative sample of 10,130 older adults who used long-term care services in 2010 were analyzed. We used the 5% sample of aged 65 years or older linked with National Health Insurance Corporation registry data of long-term care insurance system. The sample was categorized into three groups: dementia only (47.6%), stroke only (36.3%), and both dementia and stroke (16.1%). We estimated the use of institutional care, home care, and total expenditure of long-term care services, adjusting for the severity of each function (such as daily life, behavior or cognitive change, nursing care needs, and rehabilitation care needs) and sociodemographic characteristics. Results: Having dementia symptoms was positively associated with the use of institutional care services, on the other hand, having stroke symptoms was positively related with the use of home care. The total long-term care cost was higher in the group of having both dementia and stroke. Conclusion: Older persons with dementia symptoms and stroke symptoms have different patterns of long-term care utilization, and the multimorbidity increased the overall expenditure of long-term care utilization. These findings imply a need for differentiated management strategy targeting physically and cognitively impaired older persons, and special concerning for persons with multimorbidity conditions for long-term care insurance program in Korea.

• Journal of the Korean Geotechnical Society
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• v.27 no.1
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• pp.65-76
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• 2011

This paper presents the results of a numerical investigation on the long-term behavior of geosynthetic reinforced soil abutment. The investigation was carried out aiming at identifying the governing mechanisms of the long-term deformation of geosynthetic-reinforced soil abutment subjected to sustained loads during service life. A numerical modeling strategy was first established using the Singh-Mitchell creep model and the power law model, respectively, for the backfill and the geosyntehtic reinforcement. A parametric study on the creep properties of the backfill and the geosynthetic reinforcement was then conducted. The results indicated that a geosynthetic reinforced soil structure backfilled with marginal soil may exhibit substantial long-term deformation due to the creep effects caused by both the backfill soil and the geosynthetic reinforcement, the magnitude of which depends largely on the creep properties. This paper highlights the importance of considering the creep effect on load supporting geosynthetic reinforced soil structures when the long-term serviceability requirement is of prime importance.