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Case study on flood water level prediction accuracy of LSTM model according to condition of reference hydrological station combination (참조 수문관측소 구성 조건에 따른 LSTM 모형 홍수위예측 정확도 검토 사례 연구)

  • Lee, Seungho;Kim, Sooyoung;Jung, Jaewon;Yoon, Kwang Seok
    • Journal of Korea Water Resources Association
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    • v.56 no.12
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    • pp.981-992
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    • 2023
  • Due to recent global climate change, the scale of flood damage is increasing as rainfall is concentrated and its intensity increases. Rain on a scale that has not been observed in the past may fall, and long-term rainy seasons that have not been recorded may occur. These damages are also concentrated in ASEAN countries, and many people in ASEAN countries are affected, along with frequent occurrences of flooding due to typhoons and torrential rains. In particular, the Bandung region which is located in the Upper Chitarum River basin in Indonesia has topographical characteristics in the form of a basin, making it very vulnerable to flooding. Accordingly, through the Official Development Assistance (ODA), a flood forecasting and warning system was established for the Upper Citarium River basin in 2017 and is currently in operation. Nevertheless, the Upper Citarium River basin is still exposed to the risk of human and property damage in the event of a flood, so efforts to reduce damage through fast and accurate flood forecasting are continuously needed. Therefore, in this study an artificial intelligence-based river flood water level forecasting model for Dayeu Kolot as a target station was developed by using 10-minute hydrological data from 4 rainfall stations and 1 water level station. Using 10-minute hydrological observation data from 6 stations from January 2017 to January 2021, learning, verification, and testing were performed for lead time such as 0.5, 1, 2, 3, 4, 5 and 6 hour and LSTM was applied as an artificial intelligence algorithm. As a result of the study, good results were shown in model fit and error for all lead times, and as a result of reviewing the prediction accuracy according to the learning dataset conditions, it is expected to be used to build an efficient artificial intelligence-based model as it secures prediction accuracy similar to that of using all observation stations even when there are few reference stations.

A Study on the Relationships Among Learning Orientation, Innovativeness and Organizational Commitment of Entrepreneurs: Focusing on the Mediating Effect of Innovativeness and the Moderating Effect of Career Relevance (학습지향성 및 혁신성과 조직몰입 간의 관계에 관한 연구: 혁신성의 매개효과와 경력연관성의 조절효과를 중심으로)

  • Joo-Heon, Lee
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.17 no.6
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    • pp.159-174
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    • 2022
  • Entrepreneurs should continuously invest resource and capital for a long time to get tangible business results. In order to be successful, despite difficulties, it is essential for entrepreneurs to continue entrepreneurial businesses without giving up too early. Thus, it can be said that organizational commitment of entrepreneurs is essential for success. According to previous studies, the organizational commitment of entrepreneurs has a significant effect on organizing, establishments of new firms and new product developments. The purpose of this article is to examine the relationships among learning orientation, innovativeness and organizational commitment of entrepreneurs. Especially, we focus on the mediating effect of innovativeness in the relationship between learning orientation and organizational commitment and the moderating effect of career relevance among the relationships. Based on empirical analysis, we reported the following results. First, learning orientation, innovativeness and career relevance of entrepreneurs had significant positive effects on organizational commitment. Second, it was found that innovativeness of entrepreneurs has a partial mediating effect on the relationship between learning orientation and organizational commitment. Third, using Baron & Kenny's hierarchical multiple regression analysis, we examined the moderating effect of career relevance among the relationships of learning orientation, innovativeness and organizational commitment. Third, because the interaction term was found to be positively significant, it was concluded there is a moderating effect of career relevance between learning orientation and innovativeness. This means, when career relevance was higher than average, the influence of learning orientation on innovation increases even more. Fourth, it was also found there is a moderating effect of career relevance between learning orientation and organizational commitment. However, the results of the mediated moderating effect analysis showed the moderating effect of career relevance between learning orientation and organization commitment is an indirect effect of moderating effect of career relevance between learning orientation and innovativeness mediated by innovativeness.

The Effect of Environmental Factors on Competency and Performance of Venture Companies: The Double Mediating Effect of Venture Firm Confirmation System Benefits and Venture Firm Internal Competencies (벤처기업에 대한 환경적 요소가 역량 및 성과에 미치는 영향: 벤처기업 확인제도 혜택과 벤처기업 내부 역량의 이중매개효과를 중심으로)

  • Park, Dain;Kim, Daejin
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.18 no.5
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    • pp.241-253
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    • 2023
  • In the current rapidly changing environment, each country continues to make efforts to create jobs and strengthen technological competitiveness. In particular, support and revitalization policies for venture companies and start-ups are known to play a role in increasing national competitiveness. Companies should make appropriate replacements amid growing uncertainties in the environment in which business life is shortened and customer needs are diversified due to intensifying competition. First of all, it is important for companies to make efforts to strengthen their internal capabilities on their own. However, venture companies lack internal resources and capabilities, so support from the external environment is important enough to lead to the survival of the company(Timmons, 1994). Financial support and certification systems are being operated at the national level to strengthen the competitiveness of companies. However, financial support can lower a company's self-sustainability depending on the situation, so non-financial support such as R&D support and start-up education is considered to be helpful in the long term for venture growth(Aghion et al., 2012; Jeon & Ko, 2021). Non-financial support is divided into commercialization, facilities, space, childcare, manpower, and certification systems, and this study confirmed the benefits of the venture company confirmation system, which is a certification system. To this end, the 2021 venture company precision survey data and venture company sales data were used, and analyzed using the SPSS 26.0 package and SPSS PROCESS MACRO. As a result of the analysis, it was confirmed that the level of the management environment of venture companies has a positive effect on the benefits of the venture confirmation system or increasing the level of venture company capabilities, but it is difficult to lead to actual management performance. In addition, it was confirmed that the level of venture company competency mediates the relationship between the level of the venture company's business environment and management performance. As a result, even if the level of the venture company's business environment is positive or venture-friendly, it can be said that companies with internal capabilities to digest support from the external environment increase management performance.

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Venture Capital Investment and the Performance of Newly Listed Firms on KOSDAQ (벤처캐피탈 투자에 따른 코스닥 상장기업의 상장실적 및 경영성과 분석)

  • Shin, Hyeran;Han, Ingoo;Joo, Jihwan
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.17 no.2
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    • pp.33-51
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    • 2022
  • This study analyzes newly listed companies on KOSDAQ from 2011 to 2020 for both firms having experience in attracting venture investment before listing (VI) and those without having experience in attracting venture investment (NVI) by examining differences between two groups (VI and NVI) with respect to both the level of listing performance and that of firm performance (growth) after the listing. This paper conducts descriptive statistics, mean difference, and multiple regression analysis. Independent variables for regression models include VC investment, firm age at the time of listing, firm type, firm location, firm size, the age of VC, the level of expertise of VC, and the level of fitness of VC with investment company. Throughout this paper, results suggest that listing performance and post-listed growth are better for VI than NVI. VC investment shows a negative effect on the listing period and a positive effect on the sales growth rate. Also, the amount of VC investment has negative effects on the listing period and positive effects on the market capitalization at the time of IPO and on sales growth among growth indicators. Our evidence also implies a significantly positive effect on growth after listing for firms which belong to R&D specialized industries. In addition, it is statistically significant for several years that the firm age has a positive effect on the market capitalization growth rate. This shows that market seems to put the utmost importance on a long-term stability of management capability. Finally, among the VC characteristics such as the age of VC, the level of expertise of VC, and the level of fitness of VC with investment company, we point out that a higher market capitalization tends to be observed at the time of IPO when the level of expertise of anchor VC is high. Our paper differs from prior research in that we reexamine the venture ecosystem under the outbreak of coronavirus disease 2019 which stimulates the degradation of the business environment. In addition, we introduce more effective variables such as VC investment amount when examining the effect of firm type. It enables us to indirectly evaluate the validity of technology exception policy. Although our findings suggest that related policies such as the technology special listing system or the injection of funds into the venture ecosystem are still helpful, those related systems should be updated in a more timely fashion in order to support growth power of firms due to the rapid technological development. Furthermore, industry specialization is essential to achieve regional development, and the growth of the recovery market is also urgent.

The Narrative Inquiry on the Identity and Role of Local Cultural Art Director as a Local Resident: Focus on C Region Crafts Biennale (지역민인 지역문화예술 감독의 정체성과 역할에 관한 내러티브 탐구 - C지역 공예비엔날레를 중심으로 -)

  • Sa, Yuntaek
    • Korean Association of Arts Management
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    • no.50
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    • pp.101-146
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    • 2019
  • After the enactment of the Local Culture Promotion Act in 2014, the government has been continuously trying to find the direction of the local culture that reflects the local life and conforms to the local people's emotions. In response to these efforts, the Organizing Committee for the C Region Biennale has uniquely formed the Biennale Artistic Director as a local artist who includes the historical, ecological and emotional characteristics of the C region. Therefore, I sought to explore the perception of the identity and role of the local cultural arts director through the narratives of the research participants who were appointed as the local residents of the C region and the director of the Craft Biennale. For the study, six local cultural arts directors were selected as research participants, and their identity as a local cultural arts director and its role were explored, focusing on their narratives. In this process, various types of data such as photographs, documents, in - depth interviews, and conference materials were collected and narrative was analyzed based on deterministic events. The results of the investigation are as follows. The idea of the identity of the local cultural arts directors was found to be in three directions. First, it is the view that the symbolic role of the artistic supervisory system of the 10 persons guarantees the identity. Second, the identity of local cultural arts directors was recognized as a role to find ways to be localized by developing and debating cultural and artistic discourses in various regions. Third, the participants had a concern and affection for local cultural arts, not one-time but continuous, and recognized it as their identity. The directors who participated in the interviews showed that the discourse of cultural arts in various regions were developed and discussed, and they wanted to find ways to be localized. The roles of local cultural arts directors recognized by research participants in connection with their identity are as follows. First, it should be the subject of systematic and long-term planning that can close the year and connect with the art events of the following year. Second, it should play a role of academic / research that can derive the identity of social and cultural ecological analysis connected with the area. Third, local arts professionals are required to act as cultural brokers, ie local culture professionals, who can create a venue for international cultural exchanges. Research on the form of local government supervision as a mediator of local cultural arts is to find out the origin of the identity of local artists and to establish a methodology for the direction of culture and art as a subject of local people. In addition, there is a need for continued interest and research in providing a reflection on the communication and meaning of the desirable local culture, and suggesting the system for cultivating local cultural arts intermediaries.

Changes in The Sensitive Chemical Parameters of the Seawater in EEZ, Yellow Sea during and after the Sand Mining Operation (서해 EEZ 해역에서 바다모래 채굴에 민감한 해양수질인자들)

  • Yang, Jae-Sam;Jeong, Yong-Hoon;Ji, Kwang-Hee
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.13 no.1
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    • pp.1-14
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    • 2008
  • Eight comprehensive oceanographic cruises on a squared $30{\times}30\;km$ area have been made to investigate the short and long-term impacts on the water qualities due to the sand mining operations at Exclusive Economic Zone (EEZ) in the central Yellow Sea from 2004 to 2007. The area was categorized to 'Sand Mining Zone', 'Potentially Affected Zone', and 'Reference Zone'. The investigation covered suspended solids, nutrients (nitrate, nitrite, ammonium, phosphate), and chlorophyll-a in seawater and several parameters such as water temperature, salinity, pH, and ORP. Additionally, several intensive water collections were made to trace the suspended solids and other parameters along the turbid water by sand mining activities. The comprehensive investigation showed that suspended solids, nitrate, chlorophyll-a and ORP be sensitively responding parameters of seawater by sand mining operations. The intensive collection of seawater near the sand mining operation revealed that each parameter show different distribution pattern: suspended solids showed an oval-shaped distribution of the north-south direction of 8 km wide and the east-west direction of 5 km wide at the surface and bottom layers. On the other hand, phosphate showed so narrow distribution not to traceable. Also ammonium showed a limited distribution, but its boundary was connected to the high nitrate and chlorophyll-a concentrations with high N/P ratios. From the last 4 years of the comprehensive and intensive investigations, we found that suspended solids, ammonium, nitrate, chlorophyll-a, and ORP revealed the sensitive parameters of water quality for tracing the sand mining operations in seawater. Especially suspended solids and ORP would be useful tracers for monitoring the water qualities of remote area like EEZ in Yellow Sea.

Trade-off Analysis Between National Ecosystem Services Due to Long-term Land Cover Changes (장기간 토지피복 변화에 따른 국내 생태계서비스 간 상쇄효과(Trade-off) 분석)

  • Yoon-Sun Park;Young-Keun Song
    • Korean Journal of Environment and Ecology
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    • v.38 no.2
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    • pp.204-216
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    • 2024
  • Understanding the trade-off effect in ecosystem services and measuring the interrelationships between services are crucial for managing limited environmental resources. Accordingly, in this study, we identified the dominant trends and increases and decreases in ecosystem services derived from changes in land cover over about 30 years and tracked changes in the relationships between ecosystem services that occurred over time. Through it, we determined the relationship between land cover changes and ecosystem service changes, as well as the distinct characteristics of service changes in different areas. The research primarily utilized the InVEST model, an ecosystem service assessment model. After standardizing the evaluation results between 0 and 1, it went through principal component analysis, a dimensionality reduction technique, to observe the time-series changes and understand the relationships between the services. According to the research results, the area of urbanized regions dramatically increased between 1989 and 2019, while forests showed a significant increase between 2009 and 2019. Between 1989 and 2019, the national ecosystem service supply witnessed a 13.9% decrease in water supply, a 10.5% decrease in nitrogen retention, a 2.6% increase in phosphorus retention, a 0.9% decrease in carbon storage, a 1.2% increase in air purification, and a 3.4% decrease in habitat quality. Over the past 30 years, South Korea experienced an increase in urbanized areas, a decrease in agricultural land, and an increase in forests, resulting in a trade-off effect between phosphorus retention and habitat quality. This study concluded that South Korea's environment management policies contribute to improving ecosystem quality, which has declined due to urbanization, and maximizing ecosystem services. These findings can help policymakers establish and implement forestry policies focusing on sustainable environmental conservation and ecosystem service provision.

The ecological response of the climate change indicator species, Korean fir (Abies koreana E. H. Wilson) (기후변화 지표종 구상나무(Abies koreana E. H. Wilson)의 생태학적 반응)

  • Yoon Seo Kim;Se Hee Kim;Jung Min Lee;Ji Won Park;Yeo Bin Park;Jae Hoon Park;Eui Joo Kim;Kyeong Mi Cho;Yoon Kyung Choi;Ji Hyun Seo;Joo Hyun Seo;Gyu Ri Kim;Ju Seon Lee;Do Hun Ryu;Min Sun Kim;Young Han You
    • Journal of Wetlands Research
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    • v.26 no.1
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    • pp.62-71
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    • 2024
  • To assess the ecological changes of Korean fir (Abies koreana E. H. Wilson) under climate change conditions, growth and physiological responses were analyzed over a 5-year period in a control group (outdoors) and in a treatment group where the temperature and CO2 levels were elevated to closely resemble RCP 4.5 conditions. The results showed an increasing trend in annual branch length of A.koreana in the climate change treatment group over time. While climate change conditions did not significantly impact the morphological differences of A.koreana leaves, they did influence the biomass of the leaves, suggesting that as climate change progresses, the productivity of A.koreana leaves may decline. On the other hand, the chlorophyll content in A.koreana under climate change conditions was higher in the climate change treatment group, whereas the photosynthesis rate, transpiration rate, water use efficiency and stomatal conductance was higher in the control group. This suggests that an environment with elevated temperature and CO2 could influence an increase in stomatal density, but having a negative impact on photosynthetic reactions. Further research on stomatal density under each environmental treatment will be required to confirm this hypothesis. Additionally, as this study only observed changes in leaf biomass, further empirical research should be considered to understand the changes in biomass of A.koreana under climate change conditions. In conclusion, the environmental adaptability of A.koreana is expected to weaken in the long term under elevated temperatures and CO2.

Report about First Repeated Sectional Measurements of Water Property in the East Sea using Underwater Glider (수중글라이더를 활용한 동해 최초 연속 물성 단면 관측 보고)

  • GYUCHANG LIM;JONGJIN PARK
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.29 no.1
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    • pp.56-76
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    • 2024
  • We for the first time made a successful longest continuous sectional observation in the East Sea by an underwater glider during 95 days from September 18 to December 21 2020 in the Korea along the 106 Line (129.1 °E ~ 131.5 °E at 37.9 °N) of the regular shipboard measurements by the National Institute of Fishery Science (NIFS) and obtained twelve hydrographic sections with high spatiotemporal resolution. The glider was deployed at 129.1 °E in September 18 and conducted 88-days flight from September 19 to December 15 2020, yielding twelve hydrographic sections, and then recovered at 129.2 °E in December 21 after the last 6 days virtual mooring operation. During the total traveled distance of 2550 km, the estimated deviation from the predetermined zonal path had an average RMS distance of 262 m. Based on these high-resolution long-term glider measurements, we conducted a comparative study with the bi-monthly NIFS measurements in terms of spatial and temporal resolutions, and found distinguished features. One is that spatial features of sub-mesoscale such as sub-mesoscale frontal structure and intensified thermocline were detected only in the glider measurements, mainly due to glider's high spatial resolution. The other is the detection of intramonthly variations from the weekly time series of temperature and salinity, which were extracted from glider's continuous sections. Lastly, there were deviations and bias in measurements from both platforms. We argued these deviations in terms of the time scale of variation, the spatial scale of fixed-point observation, and the calibration status of CTD devices of both platforms.

Analysis of domestic water usage patterns in Chungcheong using historical data of domestic water usage and climate variables (생활용수 실적자료와 기후 변수를 활용한 충청권역 생활용수 이용량 패턴 분석)

  • Kim, Min Ji;Park, Sung Min;Lee, Kyungju;So, Byung-Jin;Kim, Tae-Woong
    • Journal of Korea Water Resources Association
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    • v.57 no.1
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    • pp.1-8
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    • 2024
  • Persistent droughts due to climate change will intensify water shortage problems in Korea. According to the 1st National Water Management Plan, the shortage of domestic and industrial waters is projected to be 0.07 billion m3/year under a 50-year drought event. A long-term prediction of water demand is essential for effectively responding to water shortage problems. Unlike industrial water, which has a relatively constant monthly usage, domestic water is analyzed on monthly basis due to apparent monthly usage patterns. We analyzed monthly water usage patterns using water usage data from 2017 to 2021 in Chungcheong, South Korea. The monthly water usage rate was calculated by dividing monthly water usage by annual water usage. We also calculated the water distribution rate considering correlations between water usage rate and climate variables. The division method that divided the monthly water usage rate by monthly average temperature resulted in the smallest absolute error. Using the division method with average temperature, we calculated the water distribution rates for the Chungcheong region. Then we predicted future water usage rates in the Chungcheong region by multiplying the average temperature of the SSP5-8.5 scenario and the water distribution rate. As a result, the average of the maximum water usage rate increased from 1.16 to 1.29 and the average of the minimum water usage rate decreased from 0.86 to 0.84, and the first quartile decreased from 0.95 to 0.93 and the third quartile increased from 1.04 to 1.06. Therefore, it is expected that the variability in monthly water usage rates will increase in the future.