• Computers and Concrete
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• v.22 no.3
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• pp.261-267
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• 2018

Long-term deformation of a steel-reinforced concrete (SRC) column is different from that of a reinforced concrete (RC) column due to the different moisture distribution. Wide-flange steel in an SRC column obstructs diffusion and makes long-term deformation slower. Previous studies analyzed the characteristics of long-term deformation of SRC columns. In this study, an additional experiment is conducted to more precisely investigate the effect of wide-flange steel on the long-term deformation of SRC columns. Long-term deformation, especially creep of SRC columns with various types of wide-flange steel, is tested. Wide-flange steel for the experiment is made of thin acrylic panels that can block diffusion but does not have strength, because the main purpose of this study is to exclusively demonstrate the long-term deformation of concrete caused by moisture diffusion, not by the reinforcement ratio. Experimental results show that the long-term deformation of a SRC column develops slower than that in a RC column, and it is slower as the wide-flange steel hinders diffusion more. These experimental results can be used for analytical prediction of long-term deformation of various SRC columns. An example of the analytical prediction is provided. According to the experimental and analytical results, it is clear that a new prediction model for long-term deformation of SRC columns should be developed in further studies.

• The Journal of Information Systems
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• v.16 no.2
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• pp.123-144
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• 2007

As the interest in the business-to-business electronic commerce is increasing, many companies are participating in the business-to-business e-marketplaces. As a result, it is important to develop understanding of behaviors of firms that use these e-marketplaces. For this purpose, e-marketplace usage company trust is proposed to affect commitment, long-term orientation and cooperation. This study, which used data from participating in the business-to-business e-marketplace companies, showed acceptable data-fit of proposed model and supported all of research hypotheses. The empirical results indicated that trust take significant effect on commitment, long-term orientation and cooperation, and the commitment affect long-term orientation and cooperation, and the commitment in turn have strong influence on long-term orientation and cooperation. It was confirmed that commitment variable is effective mediator linking trust and long-term orientation and cooperation.

• The Korean Journal of Financial Management
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• v.25 no.4
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• pp.145-182
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• 2008

As the life expectancy increases resulting in the aged society, the post-retirement life became one of the most important concerns of people. The long-term investment vehicles such as retirement savings and pension plans have been introduced to meet such demand of society. This paper examines the impact of asset allocation strategies on the long-term investment performance. Because of the unusually long investment horizon and the compounding effect, a suboptimal asset mix in a retirement plan can be a very costly and irreversible mistake. Instead of relying on anecdotal evidence to evaluate the merits of different allocation strategies, this paper performs various tests including stochastic dominance tests using both actual data and Monte Carlo simulated data that best fit the historical experience. The results indicate 1) the long-term investments perform better than the short-term investments, 2) the optimal asset allocation strategy for the long-term investments should be highly equity dominated.

• Journal of the Korean Society for Heat Treatment
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• v.34 no.6
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• pp.294-301
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• 2021

In the present study, we investigate the effects of long-term heat treatment at elevated temperatures on the mechanical softening of the Mn-Mo-Ni low-alloy steel. The influence of long-term heat treatment on microstructure and mechanical strength was evaluated. To simulate the long-term material degradation, heat treatment test was interrupted at several stages up to 10,000 hours in an electric furnace. The Mn-Mo-Ni low-alloy steel shows a typical bainitic phase, which consists of a well-developed lath substructure with fine precipitates along the lath boundaries. However, these fine precipitates were redissolved into the matrix with long-term heat treatment, and then the lath substructures were recovered. Consequently, ultimate tensile strength and yield strength decreased during long-term heat treatment showing a mechanical softening phenomenon.

• KDI Journal of Economic Policy
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• v.31 no.1
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• pp.139-167
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• 2009

A new public insurance for long-term care was introduced in July 2008 to provide for the rising demand for long-term care as the population is aging rapidly. The demand for long-term care is expected to rise further because more and more elderly are living alone or in households with only other elderly, such as his/her spouse, without informal care of their adult children. Even when the elderly are living together with their adult children, daughters and daughters in law, once the main informal care-givers, are not available because they choose to become economically active and work more over time. Experiences of countries such as Japan and Germany with similar public long-term care insurance scheme highlight the importance of detailed analysis on the demand for long-term care for the financial stability of the insurance scheme. Countries which had underestimated the demand for long-term care at the time of adopting the scheme went through financial instability of insurance schemes. This study analyzes the determinants of the demand for long-term care using data from the second demonstration project (April 2006~April 2007) of the long-term care insurance scheme for the elderly in Korea. Taking full advantage of detailed data on the long-term care, this paper analyzes the eligibility for the long-term care insurance scheme and its use. According to study results, even when common diseases among the elderly such as cancer, diabetes, arthritis, dementia, hypertension, etc. are controlled together with other individual and socioeconomic factors, limitations the elderly are faced with in their twelve activities of daily living significantly affect the eligibility for the Korean Long-term Care Insurance Scheme. This means that limitations in daily living activities are more critical than common diseases among the elderly are to the eligibility for the Korean Long-term Care Insurance Scheme. Bathing and toileting problems have been found to be the most important factor affecting the eligibility for the insurance scheme, followed by eating, dressing and moving around inside the house. Moreover, the choices of whether to use long-term care and which to use between home care and institutional care are found to be significantly influenced by health status and various socioeconomic factors of the elderly. In particular, those with more limitations in daily living activities and the female elderly are more likely to use long-term care and institutional care rather than home care. As for home care users, those living alone or with adult children and those with monthly household income of more than 500,000 won are more likely to use home care. Most importantly, even when the monthly household income of the elderly is controlled, the elderly recipients of the National Basic Living Security, who are not charged for long-term care, are more likely to choose home care. This implies that price as well as income is a critical factor for the decision to use long-term care. Further study on the duration of long-term care use will surely enhance the long-term care policy, when panel data is available for simultaneous analysis of the likelihood of long-term care use and its use duration.

• Journal of East-West Nursing Research
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• v.22 no.1
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• pp.24-31
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• 2016

Purpose: The purpose of this study was to identify and compare the differences on perceived health status, Activities of Daily Livings (ADL), social support, and residential satisfaction between long-term care hospitals and nursing homes. Methods: Data was collected through questionnaires and interviews conducted from March 29 to April 22, 2011. The subjects were 66 old adults in 3 long-term care hospitals and 53 old adults in 6 nursing homes. Data were analyzed by Pearson's correlation analysis and t-tests. Results: ADL and subjective health status in nursing homes were worse than those in long-term hospitals, but it was not statistically significant (p>.05). Old adults in nursing homes received more emotional support from other residents and staff, and received more instrumental support from staff than those in long-term care hospitals (p<.001). The mean scores of resident satisfaction in long-term care hospitals and nursing homes were 3.53 ($SD={\pm}0.36$) and 3.97 ($SD={\pm}0.44$), respectively. Resident satisfaction in nursing homes significantly was higher than long-term care hospitals (p<.001). Conclusion: Health care personnels in long-term care hospitals should enhance resident satisfaction and social support and need to coordinate long-stay patients with nursing homes.

• Communications for Statistical Applications and Methods
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• v.24 no.4
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• pp.325-337
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• 2017

In this paper, we proposed a new long-term lifetime distribution with four parameters inserted in a risk competitive scenario with decreasing, increasing and unimodal hazard rate functions, namely the Weibull-Poisson long-term distribution. This new distribution arises from a scenario of competitive latent risk, in which the lifetime associated to the particular risk is not observable, and where only the minimum lifetime value among all risks is noticed in a long-term context. However, it can also be used in any other situation as long as it fits the data well. The Weibull-Poisson long-term distribution is presented as a particular case for the new exponential-Poisson long-term distribution and Weibull long-term distribution. The properties of the proposed distribution were discussed, including its probability density, survival and hazard functions and explicit algebraic formulas for its order statistics. Assuming censored data, we considered the maximum likelihood approach for parameter estimation. For different parameter settings, sample sizes, and censoring percentages various simulation studies were performed to study the mean square error of the maximum likelihood estimative, and compare the performance of the model proposed with the particular cases. The selection criteria Akaike information criterion, Bayesian information criterion, and likelihood ratio test were used for the model selection. The relevance of the approach was illustrated on two real datasets of where the new model was compared with its particular cases observing its potential and competitiveness.

• Journal of Korean Academy of Nursing Administration
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• v.9 no.3
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• pp.353-366
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• 2003

Purpose: This study was to define the care time of elderly in long-term care facilities and to compare and analysis the care time by staff and facility types. Method: The data were collected from 530 elderly over sixty, residing in two long-term care hospitals for dementia, three long-term care hospitals for the elderly and two skilled nursing facilities. Care time for individual residents was measured the total time spent by nurses, aides. Result: The average care time measured by nursing staff was 158.6 minutes a day. The average care time for one resident by nurse was 40.4 minutes, and by aides, 118.2 minutes. The difference of the care time showed statistical significance between long-term care facility types(p<0.001) : average care time for dementia hospital(199.1min) was twice as long as that of skilled nursing facility(94.1min). Conclusion: The results of the study showed that the care time differentiates care time provided to elderly in long-term care facilities in Korea. The study suggests the need to emphasize the importance of standardization of level of staff and service programs by the long-term facilities.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.101-101
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• 2020

Traditional stochastic simulation of hydroclimatological variables often underestimates the variability and correlation structure of larger timescale due to the difficulty in preserving long-term memory. However, the Long Short-Term Memory (LSTM) model illustrates a remarkable long-term memory from the recursive hidden and cell states. The current study, therefore, employed the LSTM model in stochastic generation of hydrologic and climate variables to examine how much the LSTM model can preserve the long-term memory and overcome the drawbacks of conventional time series models such as autoregressive (AR). A trigonometric function and the Rössler system as well as real case studies for hydrological and climatological variables were tested. Results presented that the LSTM model reproduced the variability and correlation structure of the larger timescale as well as the key statistics of the original time domain better than the AR and other traditional models. The hidden and cell states of the LSTM containing the long-memory and oscillation structure following the observations allows better performance compared to the other tested conventional models. This good representation of the long-term variability can be important in water manager since future water resources planning and management is highly related with this long-term variability.

• Journal of Intelligence and Information Systems
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• v.12 no.4
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• pp.39-51
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• 2006

This study addresses how to plan purchasing and leasing of containers to satisfy the demand on containers. The problem can be further decomposed into the long-term planning and the short-term scheduling. The long-term plan specifies the composition of owned containers, long-term leasing containers, and short-term containers. The short-term plan considers the seasonality of demand and determines the time of leasing and the amount of the short-term and the long-term leasing containers. The length of the planning horizon is 10-20 years for the long-term planning, while it is one year for the short-term planning. The time unit is one year for the long-term planning, while it is one month for the short-term planning. This study discusses how to estimate the demand of containers and proposes deterministic models for scheduling purchasing and leasing of containers.