• Journal of Korean Society of Forest Science
• /
• v.100 no.1
• /
• pp.62-69
• /
• 2011

Six commonly used non-linear growth functions were fitted to individual tree height-dbh data of eight major tree species measured by the $5^{th}$ National Forest Inventory in Chungcheong province. A total of 2,681 trees were collected from permanent sample plots across Chungcheong province. The available data for each species were randomly splitted into two sets: the majority (90%) was used to estimate model parameters and the remaining data (10%) were reserved to validate the models. The performance of the models was compared and evaluated by $R^2$, RMSE, mean difference (MD), absolute mean difference (AMD) and mean difference(MD) for diameter classes. The combined data (100%) were used for final model fitting. The results showed that these six sigmoidal models were able to capture the height-diameter relationships and fit the data equally well, but produced different asymptote estimates. Sigmoidal growth models such as Chapman-Richards, Weibull functions provided the most satisfactory height predictions. The effect of model performance on stem volume estimation was also investigated. Tree volumes of different species were computed by the Forest Resources Evaluation and Prediction Program using observed range of diameter and the predicted tree total height from the six models. For trees with diameter less than 30 cm, the six height-dbh models produced very similar results for all species, while more differentiation among the models was observed for large-sized trees.

• Journal of Digital Convergence
• /
• v.18 no.12
• /
• pp.425-434
• /
• 2020

Background: Viral infection outbreaks are emerging public health concerns. They often exhibit seasonal patterns that could be predicted by the application of big data and bioinformatic analyses. Purpose: The purpose of this study was to identify trends in diarrhea-causing viruses such as rotavirus (Gr.A), norovirus G-I, and norovirus G-II in Cheonan, Korea. The identified related factors of diarrhea-causing viruses may be used to predict their trend and prevent their infections. Method: A retrospective analysis of 4,009 fecal samples from June 2010 to December 2019 was carried out at Dankook University Hospital in Cheonan. Reverse transcription-PCR (RT-PCR) was employed to identify virus strains. Information about seasonal patterns of infection was extracted and compared with local weather data. Results: Out of the 4,009 fecal samples tested using multiplex RT-PCR (mRT-PCR), 985 were positive for infection with Gr.A, G-I, and G-II. Out of these 985 cases, 95.3% (n = 939) were under 10 years of age. Gr.A, G-I, and G-II showed high infection rates in patients under 10 years of age. Student's t-test showed a significant correlation between the detection rate of Gr.A and the relative humidity. The detection rate of G-II significantly correlated with wind-chill temperature. Conclusion: Climate factors differentially modulate rotavirus and norovirus infection patterns. These observations provide novel insights into the seasonal impact on the pathogenesis of Gr.A, G-I, and G-II.

• Journal of Digital Convergence
• /
• v.18 no.12
• /
• pp.117-125
• /
• 2020

In this paper, we wanted to look at the effects of person-organization fit and person-job fit of social welfare officials on the job enthusiasm, but also examine the mediated effect of organizational committment. The study found that person-job fit has a positive effect on the job enthusiasm of public officials in charge of social welfare, and that the mediating effect of organizational committment is also partially covered. However, person-organization fit does not have a direct impact on job enthusiasm, but has been shown to have a full mediated effect through organizational committment. As a result of these studies, social welfare officials are judged to lack consistency and affinity within the organization, while their individual abilities, purposes, and demands are in line with their duties and job enthusiasm for their duties. Therefore, it is necessary to provide support at the organizational level and to create a sense of unity in order to enhance the job enthusiasm of public officials in charge of social welfare.

• Journal of Digital Convergence
• /
• v.18 no.12
• /
• pp.195-204
• /
• 2020

The purpose of this study is to look for the relationship between export weight and control volume, inland cargo, export cargo transport, ship departure. The analysis period were used for a total of 113 monthly data from January 2011 to May 2020. Data were retrieved from the Korean Statistical Information Service of the Statistics Korea. The data used in this study were performed numerical analysis, index analysis and model analysis using the rate of change from the same month of the previous year. In the trend of the increase rate, the amount of control has plummeted from 150% to 60% due to the influence of Corona 19 in the beginning of 2020. At the same time, export weight and export cargo transport also decreased. As a result of the analysis, export weight showed relatively high synchronization with export cargo transport and control volume. On the other hand, export weight and inland cargo showed relatively low synchronization. Export weight is expected to continue in 2020 after the fluctuation rate began to decrease after 2019. If we can find the point of rebound in control volume or export cargo transport in the future, we can predict the point of increase in export weight. We expect to see an increase in export weight as soon as possible.

• Korean Journal of Environmental Biology
• /
• v.39 no.2
• /
• pp.169-183
• /
• 2021

This study was carried out to investigate the flora of the Hanbando wetland (Yeongwol-gun, Gangwon-do) from April 2019 to May 2020. Vascular plants were grouped into 508 taxa, comprising 93 families, 309 genera, 456 species, 10 subspecies, 37 varieties, and 5 forms. Among the investigated 508 taxa, 2 endangered species, 8 rare plants, and 8 endemic plants were identified. The specific plants by floristic region were grouped into 71 taxa including, 3 taxa of grade V, 10 taxa of grade IV, 15 taxa of grade III, 17 taxa of grade II, and 26 taxa of grade I. Naturalized and ecosystem disturbing plants were grouped into 57 taxa and 5 taxa, respectively. The percentage of naturalized plants species and urbanization index were estimated to be 11.2% and 17.8%, respectively. This study provides important basic information for the efficient management of Hanbando wetland, which possess a high conservation value since it is forms part of the list of Ramsar wetlands.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.16 no.3
• /
• pp.73-86
• /
• 2021

The primary purpose of this paper is to explore the advanced models that predict entrepreneurial innovativeness most accurately. For the first time in the field of entrepreneurship research, it presents a model that predicts entrepreneurial innovativeness based on machine learning corresponding to data scientific approaches. It uses 22,099 the Global Entrepreneurship Monitor (GEM) data from 62 countries to build predictive models. Based on the data set consisting of 27 explanatory variables, it builds predictive models that are traditional statistical methods such as multiple regression analysis and machine learning models such as regression tree, random forest, XG boost, and artificial neural networks. Then, it compares the performance of each model. It uses indicators such as root mean square error (RMSE), mean analysis error (MAE) and correlation to evaluate the performance of the model. The analysis of result is that all five machine learning models perform better than traditional methods, while the best predictive performance model was XG boost. In predicting it through XG boost, the variables with high contribution are entrepreneurial opportunities and cross-term variables of market expansion, which indicates that the type of entrepreneur who wants to acquire opportunities in new markets exhibits high innovativeness.

• Animal Systematics, Evolution and Diversity
• /
• v.36 no.4
• /
• pp.354-362
• /
• 2020

A common snapping turtle Chelydra serpentina inhabiting North America is internationally protected as an endangered species. It is known that the individuals of common snapping turtles were imported to South Korea as pets, and after being abandoned, some inhabit the natural ecosystem of South Korea like wild animals. No genetic survey has yet been performed for the common snapping turtles imported to South Korea. Hereby, cytochrome c oxidase subunit I (COI) information, which is 594 bp long, was determined for a total of 16 C. serpentina individuals, of which one was found in nature, twelve legally imported and their descendants, and the other three were provided from the Kansas Herpetological Society, USA. The obtained data were combined with thirteen COI sequences of C. serpentina retrieved from NCBI GenBank for the subsequent population genetic analyses. The results showed that there exist five haplotypes with high sequence similarity (only three parsimoniously informative sites). In the TCS and phylogenetic analyses, all the examined C. serpentina samples coincidently formed a strong monoclade with those collected mostly from Kansas State, USA, indicating that the imported ones to South Korea are from the central North America. In addition, there found the amino acid changes and the high degree of nucleotide sequence differences between C. serpentina and C. rossignoni with some important morphological characters. It is expected that the present results could provide an important framework for systematic management and control of exotic snapping turtles imported and released to nature of South Korea.

• Journal of Apiculture
• /
• v.34 no.1
• /
• pp.47-55
• /
• 2019

Honey bees are a vital part of the food chain as the most important pollinators for a broad palette of crops and wild plants. The climate change and colony collapse disorder (CCD) phenomenon make it challenging to develop ICT solutions to predict changes in beehive and alert about potential threats. In this paper, we report the test results of the bee-counting system which stands out against the previous analogues due to its comprehensive components including an improved dual infrared sensor to detect honey bees entering and leaving the hive, environmental sensors that measure ambient and interior, a wireless network with the bluetooth low energy (BLE) to transmit the sensing data in real time to the gateway, and a cloud which accumulate and analyze data. To assess the system accuracy, 3 persons manually counted the outgoing and incoming honey bees using the video record of 360-minute length. The difference between automatic and manual measurements for outgoing and incoming scores were 3.98% and 4.43% respectively. These differences are relatively lower than previous analogues, which inspires a vision that the tested system is a good candidate to use in precise apicultural industry, scientific research and education.

• Journal of Digital Convergence
• /
• v.19 no.3
• /
• pp.319-329
• /
• 2021

This study aims to investigate Korean fashion-related research trends and knowledge structures on digital transformation through information-based approaches. Accordingly, we first identified the current status of the relevant research in Korean academic literature by year and journal; subsequently, we derived key research topics through network analysis, and then analyzed major research trends and knowledge structures by time. From 2010 to 2020, we collected 159 studies published on Korean academic platforms, cleansed data through Python 3.7, and measured centrality and network implementation through NodeXL 1.0.1. The results are as follows: first, related research has been actively conducted since 2016, mainly concentrated in clothing and art areas. Second, the online platform, AR/VR, appeared as the most frequently mentioned topic, and consumer psychological analysis, marketing strategy suggestion, and case analysis were used as the main research methods. Through clustering, major research contents for each sub-major of clothing were derived. Third, major subject by period was considered, which has, over time, changed from consumer-centered research to strategy suggestion, and design development research of platforms or services. This study contributes to enhancing insight into the fashion field on digital transformation, and can be used as a basic research to design research on related topics.

• Journal of Digital Convergence
• /
• v.19 no.3
• /
• pp.401-414
• /
• 2021

The purpose of this study was to examine the associations of Korean older adults' use of Social Network Service (SNS) and text messages with frequency of contact with 1) non-coresident adult children, 2) siblings and relatives, or 3) friends, neighbors, and acquaintances. Data were drawn from the 2017 Survey of Living Conditions and Welfare Needs of Korean Older Persons 65+ (N=8,392), and older adults were categorized into 4 groups depending on their familiarity with use of SNS and text messages. Ordinary Least Squares regression models were estimated for analyses. Results revealed that older users of both types of communication media reported frequent exchanges of calls, text messages, etc. with both family and friends. However, using SNS and text messages was consistently related to more face-to-face contact with non-family members. To conclude, older adults' familiarity with communication media could be key to exchanges of emotional and instrumental support with informal social network members and quality of life in the community. Overall, our results highlight the importance of information communication education targeting older adults for continued involvement with their informal social network members.