• Title/Summary/Keyword: change point

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Analysis of Causality of the Increase in the Port Congestion due to the COVID-19 Pandemic and BDI(Baltic Dry Index) (COVID-19 팬데믹으로 인한 체선율 증가와 부정기선 운임지수의 인과성 분석)

  • Lee, Choong-Ho;Park, Keun-Sik
    • Journal of Korea Port Economic Association
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    • v.37 no.4
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    • pp.161-173
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    • 2021
  • The shipping industry plummeted and was depressed due to the global economic crisis caused by the bankruptcy of Lehman Brothers in the US in 2008. In 2020, the shipping market also suffered from a collapse in the unstable global economic situation due to the COVID-19 pandemic, but unexpectedly, it changed to an upward trend from the end of 2020, and in 2021, it exceeded the market of the boom period of 2008. According to the Clarksons report published in May 2021, the decrease in cargo volume due to the COVID-19 pandemic in 2020 has returned to the pre-corona level by the end of 2020, and the tramper bulk carrier capacity of 103~104% of the Panamax has been in the ports due to congestion. Earnings across the bulker segments have risen to ten-year highs in recent months. In this study, as factors affecting BDI, the capacity and congestion ratio of Cape and Panamax ships on the supply side, iron ore and coal seaborne tonnge on the demand side and Granger causality test, IRF(Impulse Response Function) and FEVD(Forecast Error Variance Decomposition) were performed using VAR model to analyze the impact on BDI by congestion caused by strengthen quarantine at the port due to the COVID-19 pandemic and the loading and discharging operation delay due to the infection of the stevedore, etc and to predict the shipping market after the pandemic. As a result of the Granger causality test of variables and BDI using time series data from January 2016 to July 2021, causality was found in the Fleet and Congestion variables, and as a result of the Impulse Response Function, Congestion variable was found to have significant at both upper and lower limit of the confidence interval. As a result of the Forecast Error Variance Decomposition, Congestion variable showed an explanatory power upto 25% for the change in BDI. If the congestion in ports decreases after With Corona, it is expected that there is down-risk in the shipping market. The COVID-19 pandemic occurred not from economic factors but from an ecological factor by the pandemic is different from the past economic crisis. It is necessary to analyze from a different point of view than the past economic crisis. This study has meaningful to analyze the causality and explanatory power of Congestion factor by pandemic.

Evaluation of Crack Behavior and Climate Monitoring of Ipseok-dae Columnar Joints and Jigong Neodeol Rock Blocks in Mudeungsan National Park (무등산국립공원 입석대 주상절리 및 지공너덜 암괴의 균열 거동과 기후 모니터링 평가)

  • Noh, Jeongdu;Kang, Seong-Seung
    • The Journal of Engineering Geology
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    • v.31 no.4
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    • pp.621-630
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    • 2021
  • This study evaluated cracks and climate monitoring in Ipseok-dae columnar joints and Jigong Neodeol rock blocks in Mudeungsan National Park. The rocks' state of cracking and their surface temperatures were measured alongside air temperature, relative humidity, and wind velocity. The maximum crack behavior in Ipseok-dae was 0.367 mm at one point, and showed a slight tendency at other points. One in Jigong Neodeol was within 0.15 mm and showed a stable state with little change. The surface temperature of the Ipseok-dae columnar joints was higher on the side exposed to sunlight than on the shaded side. All blocks of Jigong Neodeol rock showed similar temperatures. The air temperature showed a similar distribution for both rock types. The air temperature showed a similar distribution for both Ipseok-dae and Jigong Neodeol. The relative humidity was mostly between 20% and 60% in Ipseok-dae and was between 20 and 70% in Jigong Neodeol. Both areas had low wind speeds, with maxima of 5 m/s in Ipseok-dae and 3 m/s in Jigong Neodeol. As a result, it is evaluated that crack behavior in Ipseok-dae columnar joints and Jigong Neodeol rock blocks have maintained a very stable state so far. The surface temperature, temperature, relative humidity, and wind velocity of the two areas showed small difference depending on the season, indicating that they were affected to some extent by the season. From a long-term perspective, this can continuously affect the deformation of the Ipseok-dae columnar joints or Jigong Neodeol rock blocks. Therefore, in order to accurately evaluate their stability, it is considered that the current microscopic delamination and exfoliation or the propagation and expansion of cracks should be continuously measured.

Grapevine Growth and Berry Development under the Agrivoltaic Solar Panels in the Vineyards (영농형 태양광 시설 설치에 따른 포도나무 생육 및 과실 특성 변화 비교)

  • Ahn, Soon Young;Lee, Dan Bi;Lee, Hae In;Myint, Zar Le;Min, Sang Yoon;Kim, Bo Myung;Oh, Wook;Jung, Jae Hak;Yun, Hae Keun
    • Journal of Bio-Environment Control
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    • v.31 no.4
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    • pp.356-365
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    • 2022
  • Agrivoltaic systems, also called solar sharing, stated from an idea that utilizes sunlight above the light saturation point of crops for power generation using solar panels. The agrivoltaic systems are expected to reduce the incident solar radiation, the consequent surface cooling effect, and evapotranspiration, and bring additional income to farms through solar power generation by combining crops with solar photovoltaics. In this study, to evaluate if agrivoltaic systems are suitable for viticulture, we investigated the microclimatic change, the growth of vines and the characteristics of grape grown under solar panels set by planting lines compared with ones in open vineyards. There was high reduction of wind speed during over-wintering season, and low soil temperature under solar panel compared to those in the open field. There was not significant difference in total carbohydrates and bud burst in bearing mother branches between plots. Despite high content of chlorophyll in vines grown under panels, there is no significant difference in shoot growth of vines, berry weight, cluster weight, total soluble solid content and acidity of berries, and anthocyanin content of berry skins in harvested grapes in vineyards under panels and open vineyards. It was observed that harvesting season was delayed by 7-10 days due to late skin coloration in grapes grown in vineyards under panels compared to ones grown in open vineyards. The results from this study would be used as data required in development of viticulture system under panel in the future and further study for evaluating the influence of agrivoltaic system on production of crops including grapes.

Playing Trauma -A Study on the Representation of History in Taiwan Horror Game Detention (플레잉 트라우마 -대만 호러게임 <반교>의 역사 재현 연구)

  • Bae, Ju-Yeon
    • Journal of Popular Narrative
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    • v.26 no.2
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    • pp.87-122
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    • 2020
  • This study explores the method of representation of traumatic history in 2D horror game Detention developed by Taiwan game production company Red Candle through an analysis of its method of storytelling. Unlike conventional public media, video/digital games are based on interactivity, in which game players engage in the narratives. Thus, the relationship between players and the history in the game world may also change. This research investigates how the players build their way of remembering and recognizing the past in a different relationship. Detention, which was well received, not only in Taiwan but also around the world upon its launch in 2017, is set in a middle school during the martial law era in Taiwan in the 1960s. In the game, the main character encounters her lost memories in the process of following clues and game rules, and finally realizes she is implicated in the 1960s' event. Detention was cinematized after the success of the game. The film achieved enormous popularity both in terms of box office success and criticism. In this paper, the strategy of the game's storytelling is introduced in comparison to the film's approach in the representation of historical events. In particular, the paper explores elements such as the interactivity of the game medium, narrative fragmentation, quests, hints and cues, and the horror genre, that asks users to understand history beyond the game world differently from the point of view of other media. Though this study, it can be considered that the digital game is a medium exploring history in a serious manner. In particular, Detention invokes the matter of game-mnemonics as well as cine-mnemonics. Compared to plentiful research in cine-mnemonics, game-mnemonics has not been extensively studied to date. Therefore, through the analysis of Detention, this paper explores the relationship between digital games, history and memory.

Type Variations of 'Stepmother' and 'Sister' in the Novels of Park Kyong-Ni and Their Meanings -Focused on Jaegwiyeol, Eunha, Kimyakgukeue Ddaldeul, Nabiwa Unggungkwi (박경리 장편소설의 '계모'·'자매' 유형 변화와 그 의미 -『재귀열』, 『은하』, 『김약국의 딸들』, 『나비와 엉겅퀴』를 중심으로)

  • Cho, Yun-A
    • Journal of Popular Narrative
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    • v.26 no.4
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    • pp.145-181
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    • 2020
  • This study analyzes type variations of the 'stepmother' and 'sister' in the full-length novels of Park Kyong-Ni and attempted to point out their meanings. The pattern of "negative stepmother" that appeared in classical and new novels also appeared repeatedly in Park Kyong-Ni's full-length novels and this was because a change took place in later full-length novels. Novels analyzed with focus were Jaegwiyeol(1959), Eunha(1960), Kimyakgukeue Ddaldeul(1962), and Nabiwa Unggungkwi(1969). The stepmother that appears in Eunha is a type that appears often in the classic and new novels of Korea. While the stepmother newly gained the role and status of 'mother', she forms a competitive relationship with the daughter of the former wife while still refusing to be a member of the family and she puts the former wife's daughter in critical situations by committing misdeeds. However, the young stepmother in Nabiwa Unggungkwi actually becomes a victim to the malicious and morbid harassment of the former wife's daughter. This stepmother is a good-natured figure who shows a sense of guilt for failing to fulfill her responsibilities of upbringing and education and she eventually dies as a victim to a bomb during the war, leaving her young biological daughter behind. On one hand, the sisters in Jaegwiyeol and Kimyakgukeue Ddaldeul are not strongly bonded but when one is caught in a crisis, the other one claims to be of help. Unlike this, the sisters in Nabiwa Unggungkwi have a bond that cannot be broken. They are half-sisters that bind each other so severely that they hinder each other's growth and they eventually end up disintegrating. Through such analyses, it is shown that issues of human nature are dealt with more acutely by breaking the 'young stepmother' away from convention by placing her in the position of the victim to amplify the conflicting relationship between sisters, unlike in previous pieces. This study was significant in that it looked into how previously repetitive character type changes appeared in full-length novels in conditions that clearly display the writer's determination to leave behind a masterpiece.

A Study of Fluoride Adsorption in Aqueous Solution Using Iron Sludge based Adsorbent at Mine Drainage Treatment Facility (광산배수 정화시설 철 슬러지 기반 흡착제를 활용한 수용액상 불소 흡착에 관한 연구)

  • Lee, Joon Hak;Kim, Sun Joon
    • Economic and Environmental Geology
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    • v.54 no.6
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    • pp.709-716
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    • 2021
  • In this study, an adsorbent prepared by natural drying of iron hydroxide-based sludge collected from settling basin at a mine drainage treatment facility located in Gangneung, Gangwon-do was used to remove fluoride in an artificial fluoride solution and mine drainage, and the adsorption characteristics of the adsorbent were investigated. As a result of analyzing the chemical composition, mineralogical properties, and specific surface area of the adsorbent used in the experiment, iron oxide (Fe2O3) occupies 79.2 wt.% as the main constituent, and a peak related to calcite (CaCO3) in the crystal structure analysis was analyzed. It was also identified that an irregular surface and a specific surface area of 216.78 m2·g-1. In the indoor batch-type experiment, the effect of changes in reaction time, pH, initial fluoride concentration and temperature on the change in adsorption amount was analyzed. The adsorption of fluoride showed an adsorption amount of 3.85 mg·g-1 16 hours after the start of the reaction, and the increase rate of the adsorption amount gradually decreased. Also, as the pH increased, the amount of fluoride adsorption decreased, and in particular, the amount of fluoride adsorption decreased rapidly around pH 5.5, the point of zero charge at which the surface charge of the adsorbent changes. Meanwhile, the results of the isotherm adsorption experiment were applied to the Langmuir and Freundlich isotherm adsorption models to infer the fluoride adsorption mechanism of the used adsorbent. To understand the thermodynamic properties of the adsorbent using the Van't Hoff equation, thermodynamic constants 𝚫H° and 𝚫G° were calculated using the adsorption amount information obtained by increasing the temperature from 25℃ to 65℃ to determine the adsorption characteristics of the adsorbent. Finally, the adsorbent was applied to the mine drainage having a fluoride concentration of about 12.8 mg·L-1, and the fluoride removal rate was about 50%.

An Exploratory Study on the Business Failure Recovery Factors of Serial Entrepreneurs: Focusing on Small Business (연속 기업가의 사업 실패 회복요인에 관한 탐색적 연구: 소상공인을 중심으로)

  • Lee, Kyung Suk;Park, Joo Yeon;Sung, Chang Soo
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.16 no.6
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    • pp.17-29
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    • 2021
  • Recently, as social distancing have been raised due to the re-spread of COVID-19, the number of serial entrepreneurs who are closing their business is rapidly increasing. Learning from failure is a source of success, but business failure can result in psychological and economic losses and negative emotions of the serial entrepreneur. At this point, it is very important to find a way to recover the negative emotions caused by business failures of serial entrepreneurs. Recently, a strategic model has emerged to deal with the negative emotions of grief caused by business failures of serial entrepreneurs. This study identified the recovery factors from the grief of business failures of serial entrepreneurs and analyzed Shepherd's(2003) three areas: loss orientation, restoration orientation, and dual process. To this end, individual in-depth interviews were conducted with 12 small business serial entrepreneurs who challenged re-startup to identify the attributes of recovery factors that were not identified with quantitative data. As a result of the study, first, recovery factors were investigated in three areas: individual orientation, family orientation, and network orientation. It was found to help improve recovery in nine categories: self-esteem, persistence, personal competence, hobbies, self-confidence, family support, networks, religion, and social support. Second, recovery obstacle factors were investigated in three areas: psychological, economic, and environmental factors. Nine categories including family, health, social network, business partner, competitor, partner, fund, external environment, and government policy were found to persist negative emotions. Third, the emotional processing process for grief was investigated in three areas: loss orientation, restoration orientation, and dual process. Ten categories such as family, partner support, social member support, government support, hobbies, networks, change of business field, moving, third-party perspective, and meditation were confirmed to enhance rapid recovery in the emotional processing process for grief. The implications of this study are as follows. The process of recovering from the grief caused by business failures of serial entrepreneurs was attempted by a qualitative study. By extending the theory of Shepherd(2003), This study can be applied to help with recovery research. In addition, conceptual models and propositions for future empirical research were presented, which can be discussed in carious academic ways.

The Philosophical Status of Scientific Theories for Science Education (과학교육을 위한 과학이론의 철학적 위치)

  • Jun-Young, Oh;Eun-Ju, Lee
    • Journal of the Korean Society of Earth Science Education
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    • v.15 no.3
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    • pp.354-372
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    • 2022
  • The purpose of this study is to explore the philosophical position of various scientific theories based on the scientific worldviews for science education. In addition, it aims to expand science education, which has usually dealt with epistemology and methodology, to ontology, that is, to the problem of metaphysics. It can be said that there exists a physical realism, traditionally defined as a strong determinism of the metaphysical belief. That is fixed and unchanging objective scientific knowledge independent of our minds, which was established by Newton, Einstein and Schridinger. What can be seen in the natural laws of dynamics can be called 'mathematicization'. Einstein also shook the traditional views to some extent through the theory of relativity, but his theory was still close to traditional thinking. On the contrary, to escape from this rigid determinism, we need anthropomorphic concepts such as 'possibility' and 'chance'. It is a characteristic of the modern scientific worldviews that leads the change of scientific theory from a classically strong deterministic thought to a weak deterministic accidental accident, probability theory, and a naturalistic point of view. This can be said to correspond to Darwin's theory of evolution and quantum mechanics. We can have three types of epistemological worlds that justify this ontological worldviews. These are rationalism, empiricism and naturalism. In many cases, science education does not tell us what kind of metaphysical beliefs the scientific theories we deal with in the field of education are based on. Also, science education focuses only on the understanding of scientific knowledge. However, it can be said that true knowledge can bring understanding only when it is connected to the knowledge of learned knowledge and the learner's own metaphysical belief in the world. Therefore, in the future, science education needs to connect various scientific theories based on scientific worldviews and philosophical position and present them to students.

Development and Assessment of a Non-face-to-face Obesity-Management Program During the Pandemic (팬데믹 시기 비대면 비만관리 프로그램의 개발 및 평가)

  • Park, Eun Jin;Hwang, Tae-Yoon;Lee, Jung Jeung;Kim, Keonyeop
    • Journal of agricultural medicine and community health
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    • v.47 no.3
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    • pp.166-180
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    • 2022
  • Objective: This study evaluated the effects of a non-face-to-face obesity management program, implemented during the pandemic. Methods: The non-face-to-face obesity management program used the Intervention mapping protocol (IMP). The program was put into effect over the course of eight weeks, from September 14 to November 13, 2020 in 48 overweight and obese adults, who applied to participate through the Daegu Citizen Health Support Center. Results: IMP was first a needs assessment was conducted; second, goal setting for behavior change was established; third, evidence-based selection of arbitration method and performance strategy was performed; fourth, program design and validation; fifth, the program was run; and sixth, the results were evaluated. The average weight after participation in the program was reduced by 1.2kg, average WC decreased by 3cm, and average BMI decreased by 0.8kg/m2 (p<0.05). The results of the health behavior survey showed a positive improvement in lifestyle factors, including average daily intake calories, fruit intake, and time spent in walking exercise before and after participation in the program. A statistically significant difference was seen (p<0.05). The satisfaction level for program process evaluation was high, at 4.57±0.63 point. Conclusion: The non-face-to-face obesity management program was useful for obesity management for adults in communities, as it enables individual counseling by experts and active participation through self-body measurement and recording without restriction by time and place. However, the program had some restrictions on participation that may relate to the age of the subject, such as skill and comfort in using a mobile app.

Exploring Changes in Science PCK Characteristics through a Family Resemblance Approach (가족유사성 접근을 통한 과학 PCK 변화 탐색)

  • Kwak, Youngsun
    • Journal of the Korean Society of Earth Science Education
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    • v.15 no.2
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    • pp.235-248
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    • 2022
  • With the changes in the future educational environment, such as the rapid decline of the school-age population and the expansion of students' choice of curriculum, changes are also required in PCK, the expertise of science teachers. In other words, the categories constituting the existing 'consensus-PCK' and the characteristics of 'science PCK' are not fixed, so more categories and characteristics can be added. The purpose of this study is to explore the potential area of science PCK required to cope with changes in the future educational environment in the form of 'Family Resemblance Science PCK (Family Resemblance-PCK, hereafter)' through Wittgenstein's family resemblance approach. For this purpose, in-depth interviews were conducted with three focus groups. In the focus group in-depth interview, participants discussed how the science PCK required for science teachers in future schools in 2030-2045 will change due to changes in the future society and educational environment. Qualitative analysis was performed based on the in-depth interview, and semantic network analysis was performed on the in-depth interview text to analyze the characteristics of 'Family Resemblance-PCK' differentiated from the existing 'consensus-PCK'. In results, the characteristics of Family Resemblance-PCK, which are newly requested along with changes in role expectations of science teachers, were examined by PCK area. As a result of semantic network analysis of Family Resemblance-PCK, it was found that Family Resemblance-PCK expands its boundaries from the existing consensus-PCK, which is the starting point, and new PCK elements were added. Looking at the aspects of Family Resemblance-PCK, [AI-Convergence Knowledge-Contents-Digital], [Community-Network-Human Resources-Relationships], [Technology-Exploration-Virtual Reality-Research], [Self-Directed Learning-Collaboration-Community], etc., form a distinct network cluster, and it is expected that future science teacher expertise will be formed and strengthened around these PCK areas. Based on the research results, changes in the professionalism of science teachers in future schools and countermeasures were proposed as a conclusion.