• Journal of the Korea Convergence Society
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• v.12 no.10
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• pp.277-286
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• 2021

This study investigated the effect of a 12-week rehabilitation program on the range of motion (ROM) and muscle strength of high school baseball players with shoulder instability. We allocated 12 players with shoulder instability to the rehabilitation group and 13 players without shoulder instability to the normal exercise group. Covariate analysis (ANCOVA) was performed to assess the ROM of the internal (IR) and external (ER) rotational joints before and after participating in the 12 weeks of rehabilitation, and two-way ANOVA was performed to assess isokinetic muscle strength. The statistical significance level was set at p<.05. The IR ROM of the dominant (D) shoulder with instability and non-dominant (ND) shoulder was significantly increased before and after the rehabilitation program. The total ROM of the D shoulder with instability significantly increased after rehabilitation. IR isokinetic strength significantly improved at an angular velocity of 180°/s after rehabilitation. These results indicate that the rehabilitation program used in this study could be effective in improving ROM and muscle strength in patients with shoulder instability. However, due to the limited results, additional research on the premise of extending the rehabilitation period is necessary.

• Korean Journal of Ecology and Environment
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• v.54 no.3
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• pp.156-169
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• 2021

Traditional morphological identification difficulties, such as phenotypic plasticity, misidentification of cryptic species, and larval stage species, can be compensated for by using DNA analysis techniques, such as DNA barcoding, in surveying zooplankton populations, including species identification. Recently, the rapid development of DNA sequencing techniques has allowed DNA-based community analysis not only for zooplankton assemblages in various aquatic ecosystems but also for the gut contents of zooplankton that are limited by conventional methods such as visual and microscopic identification. Therefore, the application of DNA sequencing can help understand biological interactions through the analysis of zooplankton food sources. The present paper introduces the major DNA-based approaches in zooplankton research topics, including taxonomic approaches by DNA barcoding, community-level approaches by metabarcoding, and gut content analyses, summarizes the analysis methods, and finally suggests the methodological topics that need to be considered for future applications.

• The Journal of the Korea Contents Association
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• v.21 no.11
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• pp.320-332
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• 2021

This paper investigates the influence of stock-level left-tail risk, which is defined using Value-at-Risk(VaR) estimates of past one-year daily stock returns, in the expected stock returns in the Korean stock market. Our results are summarized as follows: First, monthly-constructed zero-cost portfolios that buy (shortsell) the highest (lowest) left-tail risk decile in the previous month exhibit an average monthly return (called left-tail risk premium) of -2.29%. Second, Fama-MacBeth cross-sectional regressions suggest that left-tail risk in the previous month shows significant and negative explanatory power over return in this month, after controlling for various firm characteristics such as firm size, B/M, market beta, liquidity, maximum daily return, idiosyncratic volatility, and skewness. Third, the stocks with larger recent month loss have lower returns in the next month. Fourth, the magnitude of left-tail risk premium is negatively related with lagged market-level volatility. These results support the hypothesis from a perspective of behavioral finance that the overpricing of stocks with left-tail risk is attributed to the investors' underreaction to it.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.419-429
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• 2021

This study examined the differentiation and influence of socio-demographic factors that affect the daily living ability of the elderly living in urban and rural areas. The research data is 「Korean Social Life, Health and Aging Project」. The analysis target was 400 urban elderly people (K-gu, Seoul: surveyed Apr. ~ Jun. 2017) and 524 rural elderly people (B-myeon, Gyeonggi-do: surveyed Dec. 2015 ~ Feb. 2016). The research methods included descriptive statistical analysis, chi-square test through cross-analysis, correlation analysis, and logit analysis. The summary of the research results is as follows. First, the ratio of 'complete independence' in ADL/IADL was 'ADL(city)> ADL(rural)> IADL(city)> IADL(rural)". Second, the probability that the elderly living in rural areas will experience a lower ADL level and lower IADL level was 7.1 times and 3.25 times higher than that of the urban elderly. Lastly, the statistically significant variable affecting the ADL level of urban elderly was depression, and the IADL level was gender, age, economic activity, spouse presence, and depression. Age and economic activity were statistically significant variables for the ADL level of the rural elderly, and the IADL level was gender, age, and economic activity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.430-440
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• 2021

The purpose of this study was to analyze the degree of depression, cognitive function, communication ability, and the quantitative electroencephalogram (EEG) in elderly individuals with hearing loss and to investigate their inter-relationship. Hearing-impaired elderly participants, aged 60 years or older (37 men and 26 women) who visited the S Hearing Rehabilitation Center in Y City from June 20, 2020, to September 3, 2020, participated voluntarily after a recruitment announcement.The participants' overall characteristics, depression, and cognitive functions were evaluated with a structured questionnaire. The Word Recognition Score (WRS) was evaluated with an audiometer using the Korean Standard Monosyllabic Word Lists for Adults (KS-MWL-A). The quantitative EEG was measured with dry electrodes using a 2-channel EEG on the frontal lobes Fp1 and Fp2. The results are summarized as follows: Communication ability showed a positive correlation with the left-right symmetry of the frontal lobes (**p<.01) and a negative correlation with right-brain mental distraction and stress (*p<.05). In the difference WRS test for each group, the left-right symmetry of the frontal lobes (**p<.01) showed the greatest correlation with communication ability. Our results suggest that the left-right symmetry of the frontal lobes can be a biomarker indicative of the communication ability of older people with hearing impairments.

• Journal of Korea Port Economic Association
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• v.37 no.1
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• pp.19-30
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• 2021

The 21st Century Maritime Silk Road (MSR) is an important part of Belt and Road Initiative(BRI). As an economic and trade corridor for dozens of countries in Asia, Europe and Africa, and the port as an important link node, the efficiency of port operation directly affects the implementation of BRI's strategy. On the basis of combining BRI and related evaluation methods of port efficiency, this paper uses DEA-BCC model to select port production berth number and production berth length as input index container throughput and cargo throughput as output index to analyze the port efficiency of 14 ports in China. The results show that: (1) The overall efficiency level of the ports along the MSR is relatively low. Most of the ports have not reached the DEA efficiency and there are different degrees of problems in scale investment and technological improvement. However, this situation is accompanied by the implementation of China's maritime cooperation strategy and becoming better year by year. (2) The low operating efficiency of ports along China's MSR is mainly due to the lack of coordination between scale efficiency and technical efficiency, which is caused by insufficient scale investment in the port itself, weak economic linkage between the hinterland and the port, (3) Whether a port has a strong comprehensive strength does not entirely depend on the cargo throughput or scale but also includes the port's operating efficiency.

• The Journal of the Korea Contents Association
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• v.19 no.8
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• pp.572-583
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• 2019

This study sought to find out what the most ideal and appropriate native English speakers-Korean English teacher cooperative class model and the defining factors for organizing effective cooperative classes in the English education environment of our country. To achieve this goal, a total of 165 sixth graders of five elementary schools in Seoul were subject to the study. For about a month from April 1 to April 30, 2019, the survey and statistical analysis were conducted, including multiple return analysis, correlation analysis, cross analysis, and t/F verification. In summary, the results of the study are as follows. First, it was found that among the recognition of cooperative classes between native English speakers and Korean English teachers, it affected the defining factors in the order of class-related skills, task orientation, teaching-learning strategies, and motivation. Second, based on learner characteristics, the difference in perception of cooperative classes between native English speakers and Korean English teachers was verified, and the perception of native-Korean English teachers' cooperative classes was different depending on gender and the type of English cooperative classes currently participating, but the recognition of native-Korean English-Korean English cooperative classes, which were statistically significant, was not confirmed. Third, according to learner characteristics, the difference in the definition factors of the learner was verified and the difference between the sexes occurred, but the learner-defined factors according to the current type of English cooperative class did not occur. Also, there was no difference in the definition factors of scholars according to the type of English cooperative classes desired.

• Journal of Korea Technology Innovation Society
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• v.22 no.3
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• pp.362-381
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• 2019

The purpose of this study is to examine how two factors among various affecting factors of technological innovation, i.e. sectoral system of innovation and R&D support service, were actually applied in the case of NUC Electronics. This company has achieved high level of innovation performance through change of injection port and improvement of extracting rate. This was possible because each component of sectoral system of innovation system was matched with the innovation activity. The improvement of the performance in NUC Electronics was attributable to its own innovation efforts and R&D support service of government research institute. In the process of technological innovation, the company could receive high-level services in areas such as product design and virtual experiments that companies can not solve themselves. It can be said that the role of government and public institutions to support the shortage of SMEs was important. In terms of each component of sectoral system of innovation, we found that there were many opportunities of new technology; sustainability was low; imitation was easy; appropriability was low but it has dualily; accumulation of technology was relatively high, availability of external knowledge was high. At the same time, both of the company and the network played an important role, and market conditions were very favorable. In terms of R&D support services, it is a direct effect that a great deal of time and cost savings have been achieved through virtual experiments on the material and shape of the screw. As an indirect effect, the core competence of the company has been greatly strengthened by utilizing the momentum of technology development through external support, hence the company could establish the structure of virtuous circle of innovation.

• Journal of the Korea Society for Simulation
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• v.28 no.2
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• pp.35-48
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• 2019

Domestic hydraulic drifters till now have been developed by benchmarking products from overseas leading companies. However, they do not have excellent impact performance as they are not suitable for characteristics (large flow rate and low pressure) of Korean hydraulic drill power pack, and therefore, research on the optimum design has not made much headway. This study performs multi-objective function optimization for hydraulic drifters whose capacity has been redesigned to deal with the large flow rate, and also with the help of this function, it aims to improve impact power and reduce supply and surge pressure. A summary of the research study is as follows: First, we set goals for improving impact power, supply pressure, and surge pressure, and then perform multi-objective function optimization on them. After that, we secure the reliability of the optimized analytical model by comparing the test results of the prototype built by the optimized design with the analysis results of the analytical model. This study used SimulationX, that is the hydraulic system analysis software, and EasyDesign, which is a multi-objective function optimization program. Through this research, we have achieved the results that satisfy the goal of developing high power drifters suitable for Korean type hydraulic drills.

• International Area Studies Review
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• v.22 no.2
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• pp.189-209
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• 2018

The purpose of this study is to identify international research trends of SDGs by analyzing the networks among the 17 goals of the SDGs. The research scope covers the World Development and the Journal of Development Studies which are the top impact journals in the field of international development. The interconnected 17 SDGs are divided into five categories of people, planet, partnership, peace and prosperity. In this study, we analyzed the abstracts of the papers of the above two journals using Atlas.ti, a qualitative analysis software, in order to identify the connections between 17 goals. The findings from the analysis of 730 abstracts published in two journals since 2015 are summarized as follows. First, issues related to gender have featured prominently in both journals. Second, China and India have been the most popular case countries in both journals. In particular south-south cooperation led by China and India has been dealt with by the World Development. Thirdly, both journals have their own biases towards to certain SDGs. For instance, the World Development have not had many articles on SDG 11, 12, 13, 14, 15, 16 and 17. The SDGs closely associated with the environment and climate change such as 6, 12, 13, 14, and 15 have also been sidelined by the Journal of Development Studies. More balanced research paying attention to all the SDGs in an integrated and balanced manner is required to provide evidence and knowledge conducive to realizing the transformative vision of the 2030 Agenda for Sustainable Development.