• International journal of advanced smart convergence
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• 제12권4호
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• pp.55-62
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• 2023

Slotted-Aloha (S-Aloha) has been widely employed in random access networks owing to its simple implementation in a distributed manner. To enhance the throughput performance of the S-Aloha, connection-based slotted-Aloha (CS-Aloha) has been proposed in recent years. The fundamental principle of the CS-Aloha is to establish a connection with a short-sized request packet before transmitting data packets. Subsequently, the connected node transmits long-sized data packets in a batch of size M. This approach efficiently reduces collisions, resulting in improved throughput compared to the S-Aloha, particularly for a large M. In this paper, we address the short-term fairness of the CS-Aloha, as quantified by Jain's fairness index. Specifically, we evaluate how equitably the CS-Aloha allocatestime slots to all nodes in the network within a finite time interval. Through simulation studies, we identify the impact of system parameters on the short-term fairness of the CS-Aloha and propose an optimal transmission probability to support short-term fairness.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.565-569
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• 2003

One-year-long groundwater-level data have been collected from 18 wells in Cheon-an area. The result of barometric efficiency, autocorrelation, cross-correlation and statistical distribution evaluated from the measurement data shows that groundwater-level measurements from observation wells are the principal source of information about aquifer characteristics. Data from WA-2 has high barometric efficiency as well as steady decreasing auto-correlation coefficient, which means nonleaky confined aquifer, Most aquifers in this study show the unconfined properties so that barometric efficiencies are mostly low and the coefficients of cross-correlation between groundwater-level and precipitation are commonly high. This study showed that the long-term groundwater-level monitoring data without artificial stress such as pumping would give accurate information about aquifer characteristics.

• Computers and Concrete
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• 제30권5호
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• pp.301-310
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• 2022

Cement-based sensors have been widely used as structural health monitoring systems, however, their long-term sensing performance have not actively investigated. In this study, a deep learning-based methodology is adopted to predict the long-term piezoresistive properties of cement-based sensors. Samples with different multi-walled carbon nanotube contents (0.1, 0.3, and 0.5 wt.%) are fabricated, and piezoresistive tests are conducted over 10,000 loading cycles to obtain the training data. Time-dependent degradation is predicted using a modified long short-term memory (LSTM) model. The effects of different model variables including the amount of training data, number of epochs, and dropout ratio on the accuracy of predictions are analyzed. Finally, the effectiveness of the proposed approach is evaluated by comparing the predictions for long-term piezoresistive sensing performance with untrained experimental data. A sensitivity of 6% is experimentally examined in the sample containing 0.1 wt.% of MWCNTs, and predictions with accuracy up to 98% are found using the proposed LSTM model. Based on the experimental results, the proposed model is expected to be applied in the structural health monitoring systems to predict their long-term piezoresistice sensing performances during their service life.

• 유통과학연구
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• 제11권5호
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• pp.25-31
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• 2013

Purpose - This study aims to determine the effects of marketing factors on the long-term purchasing behavior regarding industrial goods, using data from wholesalers and retailers. Research design, data, and methodology - We used multiple regression analysis and 3-step regressions to investigate causality. We used 177 questionnaires targeting wholesalers and retailers of industrial goods. Results - First, long-term purchasing behavior is positively related only with advertising and marketing factors. Second, the relationship between marketing factors and brand value show that the physical environment, word-of-mouth advertising, and publicity are positively related, except advertising and sales promotion, respectively. Third, brand value and long-term purchasing behavior are positively related. Finally, brand value is not a mediator between marketing factors and long-term purchasing behavior. Conclusion - This study suggests that industrial goods providers should use marketing strategies that are different from those used in the consumer market. Further, if they want to maintain long-term relationships, they should increase their brand value.

• 지역사회간호학회지
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• 제27권1호
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• pp.21-30
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• 2016

Purpose: This research was conducted to identify long-term care service needs in the baby boom generation. Methods: Data were collected from September 3 to October 9, 2012 targeting 196 baby boomers residing in Seoul and Gyeonggi-do with the measurement of long-term care service needs having five domains. Collected data were analyzed using the SPSS 20.0 program. Results: Demand for long term care service in those who preferred nursing homes was highest as $4.40{\pm}0.69$ in the safe environment domain. In case of those preferring home care services, demand was highest as $4.37{\pm}0.56$ in the social interaction domain. People who preferred nursing homes had higher needs in personal health care and improvement of the service quality domains. Those who preferred home care services showed diverse needs according to their characteristics. Conclusion: The baby boom generation had high needs in all the domains of long-term care services and such needs were diverse according to their characteristics. However, long-term care services had limitations that they provided standardized and uniformed services only. Therefore, health care services and improved quality services should be provided in a way of meeting the users' needs, and tailored services should be provided in consideration of the users' characteristics.

• The Journal of Asian Finance, Economics and Business
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• 제7권8호
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• pp.213-224
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• 2020

The study assesses the impact of trade liberalization factors on changes in customs revenues in Vietnam. Research data was conducted between 2002 and 2017 on the official website of the Government's Web Portal and The World Bank. This paper uses the vector error correction model to estimate the short-term and long term relationship between data series. The results have proven that tariff reductions have a positive effect on short-term and long-term customs revenues in Vietnam. However, the implementation of other international commitments on trade liberalization has positive short-term and long-term negative impacts on customs revenues in Vietnam. The study's results also show that exchange rate has no effect on changes in customs revenues in the short term but it has a strong impact on increasing customs revenues in the long run. Based on these findings, the article also suggests a number of policies to ensure customs revenues in Vietnam in future. In order to ensure customs revenues, the government of Vietnam should: (1) having some policy to improve the efficiency of customs management in Vietnam; (2) Building appropriate VND exchange rate policy; (3) Establishing reasonable non - tariff barriers to prevent fraud and ovations cause losses in customs revenues.

• 아태비즈니스연구
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• 제12권4호
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• pp.253-270
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• 2021

Purpose - The main purpose of this study is to measure and evaluate the level of national liabilities that Korea's national finances can afford. Specifically, the concepts of national debt and national liability are clarified, and the appropriate level of national liabilities is measured in terms of short-term fiscal crisis, mid-to-long-term fiscal crisis, and GDP. Based on these measurements of fiscal crisis, this study would like to propose national fiscal management plans. Design/methodology/approach - In order to clearly recognize the difference between the national debt and the national liability, this study examines the data from 2013 to 2020. In addition, this study uses data from the national financial statements from 2013 to 2018 to measure the appropriate level of national liabilities in terms of fiscal crisis management. Findings - Short-term fiscal crises, measured by current ratios, will not occur. Nevertheless, in view of the cash flow compensation ratio, the short-term bankruptcy of the national finances of Korea depends on the re-borrowing of short-term borrowings and current and long-term borrowings. In addition, in order to manage the mid-to long-term financial crisis, it is necessary to pay attention to the liability growth rate rather than the liability size. Research implications or Originality - While previous studies focused on the appropriate level of national debt, this study was differentiated as a study focused on the level of national liability coverage. It is expected that the results of this study will be used to manage the national fiscal soundness.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.135-136
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• 2022

Defects caused by apartment houses have the term of warranty liability according to the enforcement ordinance of Acts of the Management of Apartment Houses. In case when defects occur during the term, free defect maintenance can be provided from the construction company. Yet, there occur conflicts between the construction company and residents, as to whether there occur defects or not. To resolve these conflicts, this study aimed to analyze construction classification and types that need managing, based on defects of apartment houses occurring during the term of warranty liability. This research analyzed 138,576 cases of data, as of five apartment house complexes. For the construction classification for defects of apartment houses, wooden flooring products accounted for the highest rate, followed by paper hanging, and wooden window. For the construction types of defects, torn/scratching took up with the highest rate, followed by the condition of defect in fixing and operating. In order to embody defects occurring during the term of warranty liability, into the visualization technique, this researcher utilized the word cloud method. This study will pursue the method for maintaining defects during the term of warranty liability, in the subsequent research, using the data that this research presented.

• 한국보건간호학회지
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• 제30권3호
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• pp.512-525
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• 2016

Purpose: Ageing in place may improve the quality of life of frail elderly and decrease their costs of services. The purpose of this study was to examine the factors that influence the institutionalization of elderly using home care services in a Korean long-term care insurance system. Methods: This study used the data of '2009 Satisfaction survey of Korean long-term care system'. The survey proceeded to use a sampling data based on region, level of long-term care need, and insurance type among the beneficiaries between August and September 2009. The onset dates of institutionalization of 1,095 participants were ascertained from long-term care insurance claim data. This study calculated the hazard ratio through the Cox Proportional Hazard Model. Results: A total of 176 subjects who were institutionalized in nursing homes were included. There were higher risks in the group that included those who were 85 years and over, had dementia or fracture, used home-visit nursing service, and were not supported by direct family. Conclusion: The results of this study have policy implications to supplement the home care service system and postpone nursing home institutionalization of elderly.

• 한국보건간호학회지
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• 제33권1호
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• pp.98-108
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• 2019

Purpose: The purpose of this study was to identify factors influencing care workers' patient safety behaviors (PSB), we hoped to provide baseline data for its activation. Methods: The subjects of this study were chosen by convenience sampling, which included 114 care workers at long term care facilities. Data were collected from August 22 to October 10, 2018. The gathered data were analyzed using the SPSS program, which was used to Cronbach's alpha, descriptive statistics, t-test, ANOVA, Pearson correlation coefficient and stepwise regression. Results: The care workers' average PSB was at 7.81 points, patient safety culture (PSC) 3.86 points and safety of long-term care facilities 7.07. PSB positively correlated with safety of facilities(r=.802, p<.001) and PSC(r=.558, p<.001). Work attitude and satisfaction of job were explained 35.1% of the PSB. Conclusion: Administrators of long term care facilities should be interested in patient safety culture and improving job satisfaction of care workers in order to improve patient safety behaviors.