• Title/Summary/Keyword: Distribution Science Research

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Fish Community Characteristics and Habitat Aspects of Endangered Species, Rhodeus pseudosericeus in Heuk Stream, a Tributary of the Han River Drainage System (한강지류 흑천의 어류군집 특성 및 멸종위기종 한강납줄개의 서식양상)

  • Ko, Myeong-Hun;Myung, Ra-Yeon;Kim, Hyeong-Su
    • Korean Journal of Environment and Ecology
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    • v.33 no.3
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    • pp.266-279
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    • 2019
  • We investigated the characteristics of fish communities and habitat status of endangered species Rhodeus pseudosericeus in Heuk Stream, a tributary of the Han River, from April to October 2018. During this period, we collected 47 species of 14 families from 10 survey stations using kick nets, cast nets, and long bag set nets. The dominant and subdominant species were Zacco platypus (37.6%) and Z. koreanus (13.8%), respectively. The next most abundant species were Squalidus gracilis majimae (11.1%), Pungtungia herzi (7.7%), Rhodeus pseudosericeus (5.0%), Microphysogobio yaluensis (4.3%), and Hemibarbus longirostris (3.0%). Among the fish collected, 19 species (40.4%) were Korean endemic species. Endangered species were R. pseudosericeus and Acheilognathus signifer while exotic species were Micropterus salmoides and Oncorhynchus mykiss, and land-locked species were Plecoglossus altivelis and Rhinogobius brunneus. The community analysis showed that the dominance and evenness indexes were mostly low and that the diversity and richness indexes were high. Moreover, the river health (index of biological integrity) was mostly excllent (1 site is good, 9 sites are very good). R. pseudosericeus inhabited widely from St. 3 to St. 9 in Heuk Stream, and its population size was large. Age groups for R. pseudosericeus estimated by the frequency distribution of total length in spawning season (April) indicated the 32~45 mm group as 1-year old, the 46~59 mm group as 2-years old, 60~69 mm group as 3-years old, and the 70~89 mm group as 4-years or older. Total length range of male and female was similar, and the sex ratio of female (426) to male (394) was 1 : 0.95. A. signifer, which had been released in Heuk Stream, inhabited from St. 4 to St. 5, but its population size was small. Lastly, this paper discusses a conservation plan for fish in Heuk Stream.

Case Study on Success and Innovation Activities of Women Entrepreneurs: Focusing on Startups (여성 창업가의 성공과 혁신활동에 대한 사례 연구 : 스타트업을 중심으로)

  • Hong, Jungim;Kim, Sunwoo
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.16 no.1
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    • pp.55-69
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    • 2021
  • For the national economic development, the participation of women in the social and economic activities is crucial. The popularization of start-ups, digital transformation, and WEconomy trends have lowered the barriers to opportunities for women to start a business and provide an environment in which women can grow faster. This paper examines the significance and process of success of women entrepreneurs and the characteristics of innovation strategies and achievements by linking the recently changing business environment of a company, factors influencing the success of women entrepreneurship, and innovation activities. To this end, four companies' cases were analyzed in the fields of distribution/service and consumer products/services, which are areas of large investment among female startups. The result shows that women entrepreneurs recognize the meaning of success as creating and continuing to create a 'corporate value through establishing a trust relationship with customers' within the 'balance between personal life and work.' In terms of the business ecosystem, women entrepreneurs strive for 'business activities based on the win-win growth of consumers, producers and sellers' for success, and rather 'focus on the process with a problem-solving approach' rather than achieving performance-oriented goals. Also through excellent power of observation, flexibility, and execution power, women entrepreneurs conduct business by adapting to changing trends. In terms of innovation activities, the innovation strategy of women-led companies puts priority on 'creating the value customers want' and focuses on innovation in the 'customer-centric business model' rather than technological innovation. As such, women-led companies show several differentiated characteristics, which enable them to create corporate value and achieve sustainable growth. The barriers to challenges and opportunities for women to start a business have been lowered, and an ecosystem has been created for female startups to grow. But why are there still so few women entrepreneurs, and the answer to where we need to close these gaps is ultimately a close analysis and investigation of the field. We must present milestones for growth steps through the accumulation of case studies of women startups that have exited. In addition, women can stand as economic agents only when the policy targets are subdivided and specific approaches to child-rearing and childcare for women entrepreneurs must be taken. This paper expects to serve as basic data for follow-up studies and become the basis of research for women entrepreneurs to grow as economic agents.

Anti-listeria Activity of Lactococcus lactis Strains Isolated from Kimchi and Characteristics of Partially Purified Bacteriocins (김치에서 분리한 Lactococcus lactis 균주의 항리스테리아 활성 및 부분 정제된 박테리오신의 특성)

  • Son, Na-Yeon;Kim, Tae-Woon;Yuk, Hyun-Gyun
    • Journal of Food Hygiene and Safety
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    • v.37 no.2
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    • pp.97-106
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    • 2022
  • Listeria monocytogenes (L. monocytogenes) is one of gram-positive foodborne pathogens with a very high fatality rate. Unlike most foodborne pathogens, L. monocytogenes is capable of growing at low temperatures, such as in refrigerated foods. Thus, various physical and chemical prevention methods are used in the manufacturing, processing and distribution of food. However, there are limitations to the methods such as possible changes to the food quality and the consumer awareness of synthetic preservatives. Thus, the aim of this study was to evaluate the anti-listeria activity of lactic acid bacteria (LAB) isolated from kimchi and characterize the bacteriocin produced by Lactococcuslactis which is one of isolated strains from kimchi. The analysis on the anti-listeria activity of a total of 36 species (Lactobacillus, Weissella, Lactobacillus, and Lactococcus) isolated from kimchi by the agar overlay method revealed that L. lactis NJ 1-10 and NJ 1-16 had the highest anti-listeria activity. For quantitatively analysis on the anti-listeria activity, NJ 1-10 and NJ 1-16 were co-cultured with L. monocytogenes in Brain Heat Infusion (BHI) broth, respectively. As a result, L. monocytogenes was reduced by 3.0 log CFU/mL in 20 h, lowering the number of bacteria to below the detection limit. Both LAB strains showed anti-listeria activity against 24 serotypes of L. monocytogenes, although the sizes of clear zone was slightly different. No clear zone was observed when the supernatants of both LAB cultures were treated with proteinase-K, indicating that their anti-listerial activities might be due to the production of bacteriocins. Heat stability of the partially purified bacteriocins of NJ 1-10 and NJ 1-16 was relatively stable at 60℃ and 80℃. Yet, their anti-listeria activities were completely lost by 60 min of treatment at 100℃ and 15 min of treatment at 121℃. The analysis on the pH stability showed that their anti-listeria activities were the most stable at pH 4.01, and decreased with the increasing pH value, yet, was not completely lost. Partially purified bacteriocins showed relatively stable anti-listeria activities in acetone, ethanol, and methanol, but their activities were reduced after chloroform treatment, yet was not completely lost. Conclusively, this study revealed that the bacteriocins produced by NJ 1-10 and NJ 1-16 effectively reduced L. monocytogenes, and that they were relatively stable against heat, pH, and organic solvents, therefore implying their potential as a natural antibacterial substance for controlling L. monocytogenes in food.

Changes in the Linear Compressibility and Bulk Modulus of Natural Stilbite Under Pressure with Varying Pressure-Transmitting Media (천연 스틸바이트의 압력전달매개체에 따른 선형압축률 및 체적탄성률 비교 연구)

  • Hwang, Huijeong;Lee, Hyunseung;Lee, Soojin;Jung, Jaewoo;Lee, Yongmoon
    • Korean Journal of Mineralogy and Petrology
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    • v.35 no.3
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    • pp.367-376
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    • 2022
  • This study is a preliminary step to understand the reaction between various liquids and zeolite in the subduction zone environment. Stilbite, NaCa4(Al9Si27)O72·28(H2O), was selected and high pressure study was conducted on compressional behavior by the pressure-transmitting medium (PTM). Water and NaHCO3 solution that can exist in the subduction zone was used as PTM, and samples were pressurized from ambient to a maximum of 2.5 GPa. Below 1.0 GPa, both experiments show a low linear compressibility in the range of 0.001 to 0.004 GPa-1 and a high bulk modulus of 220(1) GPa. This is presumably because the structure of the stilbite becomes very dense due to insertion of water molecules or cations into the channel. On the other hand, at 1.0 GPa or higher, the trends of the two experiments are different. In the water run, the linear compressibility of the c-axis is increased to 0.006(1) GPa-1. In the NaHCO3 run, the linear compressibility of the b- and c-axis is increased to 0.006(1) GPa-1. The bulk modulus after 1.0 GPa shows values of 40(1) and 52(7) GPa in water and NaHCO3 run, respectively, confirming that stilbite becomes more compressible than that before 1.0 GPa. It is caused by the migration of cations and water molecules inside the channel, as the water molecules in the PTM start to freeze and stop to insert toward the channel at 1.0 GPa or more. In the NaHCO3 run, it is assumed that the distribution of extra-framework species inside the structure is changed by substitution of the Na+ cation. It can be expected from tendency of the relative intensity ratio of the (001) and (020) peaks which show a different from that of the water run.

Early Effect of Environment-friendly Harvesting on the Dynamics of Organic Matter in a Japanese Larch (Larix leptolepis) Forest in Central Korea (중부지역 일본잎갈나무림의 친환경벌채가 산림 내 유기물 변화에 미치는 초기 영향)

  • Wang, Rui Jia;Kim, Dong Yeob
    • Journal of Korean Society of Forest Science
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    • v.111 no.4
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    • pp.473-481
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    • 2022
  • Environment-friendly harvesting is practiced to maintain ecosystem, landscape, and forest protection functions. The present study was conducted at Simgok-ri, Sinbuk-myeon, Pocheon, Gyeonngi-do, where a 41-50-year-old Japanese larch forest was harvested in an environment-friendly manner from 2017 to 2019. The dynamics of organic matter in this forest were investigated at three years after the harvest. Specifically, organic matter content was measured on the forest floor and in overstory biomass, litterfall, and soil up to 30 cm in depth from June 2020 to January 2021. Owing to the harvest, the amount of overstory biomass of the Japanese larch stands decreased from 142.22 to 44.20 t ha-1. On the forest floor, the amount of organic matter was 32.87 t ha-1 in the control plots and 23.34 t ha-1 in the harvest plots. Annual litterfall was 4.43 t ha-1 yr-1 in the control plots and 1.16 t ha-1 yr-1 in the harvest plots. Soil bulk density in the B horizon was 0.97 g cm-3 in the control plots and 1.06 g cm-3 i n the harvest plots. Soil organic matter content was 11.5% in the control plots and 12.8% in the harvest plots. The total amount of soil organic matter did not differ significantly between the control plots (245.21 t ha-1) and harvest plots (263.92 t ha-1), although the amount of soil organic matter tended to be higher in the harvest plots. The total amount of organic matter in the forest was estimated to be 406.48 t ha-1 in the control plots and 338.21 t ha-1 in the harvest plots. In the harvest plots, the ratio of aboveground organic matter decreased to 13.1% and soil organic matter increased to 78.0%, indicating that the distribution of organic matter changed significantly in these plots. Overall, the carbon accumulated in aboveground biomass was substantially reduced by environment-friendly harvesting, whereas the soil carbon level increased, which played a role in mitigating the reduction of system carbon in the forest. These results highlight one possible resolution for forest management in terms of coping with climate change. However, given that only three years of environment-friendly harvesting data were analyzed, further research on the dynamics of organic matter and tree growth is needed.

A Study on the Policy Directions of Sports Welfare in Gangwon Province for Improving Quality of Life (삶의 질 향상을 위한 강원도 스포츠복지 정책방향 연구)

  • Kim, Heung-Tae;Kim, Tae-Dong
    • Journal of Korea Entertainment Industry Association
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    • v.13 no.8
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    • pp.411-424
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    • 2019
  • The purpose of this study is to explore the feasible policy directions for sports welfare that can not only improve the standard of living through health but also ensure a happy and enjoyable life for the people of Gangwon Province. For this purpose, I have conducted studies such as the analysis on the sports class voucher project being implemented by the South Korean government and the case analysis in sports welfare, and present policy directions as follows. First of all, it is about upgrading the sports class voucher project. And as its implementation plans, I suggest ① increased publicity, ② the earmarking of the province's own budget for the sports class voucher project, ③ the establishment of a system for cooperation for work implementation between the related organizations and their staff in charge with a view to activating the sports class voucher project, and ④ the upgraded services for the sports class voucher project and the upgraded access to the life cycle-based universal welfare. Second, it is about using public sports facilities and developing various programs. I suggest the active utilization of the public sports facilities that enable people to learn the skills for such sports disciplines as baseball, badminton, ice sports, and golf and the development and distribution of distinctive educational programs for dance for media entertainment shows for female youths, climbing, cheer leading, fencing, surfing and horseback riding. Third, it is about nurturing the human resources and networking. For this, I suggest the creation of 'Sports Welfare Specialist Training Program' and the training of the college students majoring in sports science with the aim of creating a number of jobs. Fourth, it is about refurbishing the system and establishing the support system. I suggest the dismantling of the partitions in the welfare policy related to sports activities and the formation of (tentatively named) 'Gangwon Province Sports Welfare Implementation Committee', and the creation of (tentatively named) 'Sports Welfare Project Support Team' in Health, Welfare & Women's Affairs Bureau or Culture, Tourism and Sports Bureau in the short term and then its long-term expansion into (tentatively named) 'Gangwon Province Sports Welfare Support Center' in responding to the needs that reflect the provincial demographics, with a view to establishing a single lineup for the administrative support system. Furthermore, as budget and manpower are needed to realize customized sports welfare that suits the characteristics of the province and in which all the provincial residents can collect benefits, I suggest that the province provide the legal basis through creating 'Ordinance Promoting Sports Welfare in Gangwon Province' and pushing forward with (tentatively named) 'Gangwon Province Sports Welfare Competition' as what revises the sports class voucher project for the purpose of broadening the basis for sports welfare promotion.

A Study of 'Emotion Trigger' by Text Mining Techniques (텍스트 마이닝을 이용한 감정 유발 요인 'Emotion Trigger'에 관한 연구)

  • An, Juyoung;Bae, Junghwan;Han, Namgi;Song, Min
    • Journal of Intelligence and Information Systems
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    • v.21 no.2
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    • pp.69-92
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    • 2015
  • The explosion of social media data has led to apply text-mining techniques to analyze big social media data in a more rigorous manner. Even if social media text analysis algorithms were improved, previous approaches to social media text analysis have some limitations. In the field of sentiment analysis of social media written in Korean, there are two typical approaches. One is the linguistic approach using machine learning, which is the most common approach. Some studies have been conducted by adding grammatical factors to feature sets for training classification model. The other approach adopts the semantic analysis method to sentiment analysis, but this approach is mainly applied to English texts. To overcome these limitations, this study applies the Word2Vec algorithm which is an extension of the neural network algorithms to deal with more extensive semantic features that were underestimated in existing sentiment analysis. The result from adopting the Word2Vec algorithm is compared to the result from co-occurrence analysis to identify the difference between two approaches. The results show that the distribution related word extracted by Word2Vec algorithm in that the words represent some emotion about the keyword used are three times more than extracted by co-occurrence analysis. The reason of the difference between two results comes from Word2Vec's semantic features vectorization. Therefore, it is possible to say that Word2Vec algorithm is able to catch the hidden related words which have not been found in traditional analysis. In addition, Part Of Speech (POS) tagging for Korean is used to detect adjective as "emotional word" in Korean. In addition, the emotion words extracted from the text are converted into word vector by the Word2Vec algorithm to find related words. Among these related words, noun words are selected because each word of them would have causal relationship with "emotional word" in the sentence. The process of extracting these trigger factor of emotional word is named "Emotion Trigger" in this study. As a case study, the datasets used in the study are collected by searching using three keywords: professor, prosecutor, and doctor in that these keywords contain rich public emotion and opinion. Advanced data collecting was conducted to select secondary keywords for data gathering. The secondary keywords for each keyword used to gather the data to be used in actual analysis are followed: Professor (sexual assault, misappropriation of research money, recruitment irregularities, polifessor), Doctor (Shin hae-chul sky hospital, drinking and plastic surgery, rebate) Prosecutor (lewd behavior, sponsor). The size of the text data is about to 100,000(Professor: 25720, Doctor: 35110, Prosecutor: 43225) and the data are gathered from news, blog, and twitter to reflect various level of public emotion into text data analysis. As a visualization method, Gephi (http://gephi.github.io) was used and every program used in text processing and analysis are java coding. The contributions of this study are as follows: First, different approaches for sentiment analysis are integrated to overcome the limitations of existing approaches. Secondly, finding Emotion Trigger can detect the hidden connections to public emotion which existing method cannot detect. Finally, the approach used in this study could be generalized regardless of types of text data. The limitation of this study is that it is hard to say the word extracted by Emotion Trigger processing has significantly causal relationship with emotional word in a sentence. The future study will be conducted to clarify the causal relationship between emotional words and the words extracted by Emotion Trigger by comparing with the relationships manually tagged. Furthermore, the text data used in Emotion Trigger are twitter, so the data have a number of distinct features which we did not deal with in this study. These features will be considered in further study.

Expanded Uses and Trend of Domestic and International Research of Rose of Sharon(Hibiscus syriacus L.) as Korean National Flower since the Protection of New Plant Variety (식물신품종보호제도 이후 나라꽃 무궁화의 국내외 연구동향 및 확대 이용 방안)

  • Kang, Ho Chul;Kim, Dong Yeob;Wang, Yae Ga;Ha, Yoo Mi
    • Journal of the Korean Institute of Landscape Architecture
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    • v.47 no.5
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    • pp.49-65
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    • 2019
  • This study was carried out to investigate the domestic and international development of a new cultivar of the Rose of Sharon (Hibiscus syriacus L.), the Korean national flower, and the protection of the new plant variety. In addition, it will be used as basic data for the expansion of domestic distribution, promoting oversea export, and expanding the range of landscape architectural use. A total of 97 varieties received plant variety protection rights from the Korea Seed & Variety Service from 2004 to 2018. The selection criteria were plants having unique flowers, growth habits, and variegated leaves. Some cultivars with unique features, such as flower size, shape, and red eyes were available for focus planting. Plant varieties with tall and strong growth patterns have been highly valuable for street and focus planting. Cultivars with dwarf stems and compact branches are utilized for pot planting and bonsai. The protected cultivars were mostly single flower varieties, with two semi-double flowers. There were 57 cultivars of pink flowers with red eyes and 21 cultivars of white flowers with red eyes. There were 61 cultivars developed by crossing, 23 cultivars through interspecific hybridization and 7 cultivars developed through radiation treatment and mutation. The Hibiscus cultivars registered to the United States Patent and Trademark Office (USPTO) consisted of seven cultivars each from the United States, the United Kingdom, and the Netherlands, four from South Korea, and three from Belgium. The Hibiscus cultivars registered to the European Community Plant Variety Office (CPVO) consisted of 16 cultivars from France, 9 from the Netherlands, 5 from the UK and 1 from Belgium. The cultivars that received both plant patent and plant breeder rights in the United States and Canada were 'America Irene Scott', 'Antong Two', 'CARPA', 'DVPazurri', 'Gandini Santiago', 'Gandini van Aart', 'ILVO347', 'ILVOPS', 'JWNWOOD 4', 'Notwood3', 'RWOODS5', 'SHIMCR1', 'SHIMRR38', 'SHIMRV24', and 'THEISSHSSTL'. 'SHIMCR1' and 'SHIMRV24' acquired both domestic plant protection rights and overseas plant patents. The 14 cultivars that received both US plant patents and European protection rights were 'America Irene Scott', 'Bricutts', 'DVPAZURRI', 'Gandini Santiago', 'Gandini van Aart', 'JWNWOOD4', 'MINDOUB1', 'MINDOUR1', 'MINDOUV5', 'NOTWOOD3', 'RWOODS5', 'RWOODS6', 'Summer Holiday', and 'Summer Night'. The cultivars that obtained US patents consisted of 18 cultivars (52.9%) with double flowers, 4 cultivars (11.8%) with semi-double flowers, and 12 cultivars (35.3%) with single flowers. The cultivars that obtained European new variety protection rights, consisted of 11 cultivars (34.3%) with double flowers, 12 cultivars (21.9%) with semi-double flowers, and 14 cultivars (43.8%) with single flowers. In the future, new cultivars of H. syriacus need to be developed in order to expand domestic distribution and export abroad. In addition, when developing new cultivars, it is required to develop cultivars with shorter branches for use in flower beds, borders, hedges, and pot planting.

A Study on Improvement on National Legislation for Sustainable Progress of Space Development Project (우주개발사업의 지속발전을 위한 국내입법의 개선방향에 관한 연구)

  • Lee, Kang-Bin
    • The Korean Journal of Air & Space Law and Policy
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    • v.25 no.1
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    • pp.97-158
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    • 2010
  • The purpose of this paper is to research on the contents and improvement of national legislations relating to space development in Korea to make the sustainable progress of space development project in Korea. Korea has launched its first satellite KITST-1 in 1992. The National Space Committee has established "The Space Development Promotion Basic Plan" in 2007. The plan addressed the development of total 13 satellites by 2010 and the space launch vehicle by 2020, and the launch of moon exploration spaceship by 2021. Korea has built the space center at Oinarodo, Goheng Province in June 2009. In Korea the first small launch vehicle KSLV-1 was launched at the Naro Space Center in August 2009, and its second launch was made in June 2010. The United Nations has adopted five treaties relating to the development of outer space as follows : The Outer Space Treaty of 1967, the Rescue and Return Agreement of 1968, the Liability Convention of 1972, the Registration Convention of 1974, and the Moon Treaty of 1979. All five treaties has come into force. Korea has ratified the Outer Space Treaty, the Rescue and Return Agreement, the Liability Convention and the Registration Convention excepting the Moon Treaty. Most of development countries have enacted the national legislation relating to the development of our space as follows : The National Aeronautic and Space Act of 1958 and the Commercial Space Act of 1998 in the United States, Outer Space Act of 1986 in England, Establishment Act of National Space Center of 1961 in France, Canadian Space Agency Act of 1990 in Canada, Space Basic Act of 2008 in Japan, and Law on Space Activity of 1993 in Russia. There are currently three national legislations relating to space development in Korea as follows : Aerospace Industry Development Promotion Act of 1987, Outer Space Development Promotion Act of 2005, Outer Space Damage Compensation Act of 2008. The Ministry of Knowledge Economy of Korea has announced the Full Amendment Draft of Aerospace Industry Development Promotion Act in December 2009, and it's main contents are as follows : (1) Changing the title of Act into Aerospace Industry Promotion Act, (2) Newly regulating the definition of air flight test place, etc., (3) Establishment of aerospace industry basic plan, establishment of aerospace industry committee, (4) Project for promoting aerospace industry, (5) Exploration development, international joint development, (6) Cooperative research development, (7) Mutual benefit project, (8) Project for furthering basis of aerospace industry, (9) Activating cluster of aerospace industry, (10) Designation of air flight test place, etc., (11) Abolishing the designation and assistance of specific enterprise, (12) Abolishing the inspection of performance and quality. The Outer Space Development Promotion Act should be revised with regard to the following matters : (1) Overlapping problem in legal system between the Outer Space Development Promotion Act and the Aerospace industry Development promotion Act, (2) Distribution and adjustment problem of the national research development budget for space development between National Space Committee and National Science Technology Committee, (3) Consideration and preservation of environment in space development, (4) Taking the legal action and maintaining the legal system for policy and regulation relating to space development. The Outer Space Damage Compensation Act should be revised with regard to the following matters : (1) Definition of space damage and indirect damage, (2) Currency unit of limit of compensation liability, (3) Joint liability and compensation claim right of launching person of space object, (4) Establishment of Space Damage Compensation Council. In Korea, it will be possible to make a space tourism in 2013, and it is planned to introduce and operate a manned spaceship in 2013. Therefore, it is necessary to develop the policy relating to the promotion of commercial space transportation industry. Also it is necessary to make the proper maintenance of the current Aviation Law and space development-related laws and regulations for the promotion of space transportation industry in Korea.

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Analysis of Twitter for 2012 South Korea Presidential Election by Text Mining Techniques (텍스트 마이닝을 이용한 2012년 한국대선 관련 트위터 분석)

  • Bae, Jung-Hwan;Son, Ji-Eun;Song, Min
    • Journal of Intelligence and Information Systems
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    • v.19 no.3
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    • pp.141-156
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    • 2013
  • Social media is a representative form of the Web 2.0 that shapes the change of a user's information behavior by allowing users to produce their own contents without any expert skills. In particular, as a new communication medium, it has a profound impact on the social change by enabling users to communicate with the masses and acquaintances their opinions and thoughts. Social media data plays a significant role in an emerging Big Data arena. A variety of research areas such as social network analysis, opinion mining, and so on, therefore, have paid attention to discover meaningful information from vast amounts of data buried in social media. Social media has recently become main foci to the field of Information Retrieval and Text Mining because not only it produces massive unstructured textual data in real-time but also it serves as an influential channel for opinion leading. But most of the previous studies have adopted broad-brush and limited approaches. These approaches have made it difficult to find and analyze new information. To overcome these limitations, we developed a real-time Twitter trend mining system to capture the trend in real-time processing big stream datasets of Twitter. The system offers the functions of term co-occurrence retrieval, visualization of Twitter users by query, similarity calculation between two users, topic modeling to keep track of changes of topical trend, and mention-based user network analysis. In addition, we conducted a case study on the 2012 Korean presidential election. We collected 1,737,969 tweets which contain candidates' name and election on Twitter in Korea (http://www.twitter.com/) for one month in 2012 (October 1 to October 31). The case study shows that the system provides useful information and detects the trend of society effectively. The system also retrieves the list of terms co-occurred by given query terms. We compare the results of term co-occurrence retrieval by giving influential candidates' name, 'Geun Hae Park', 'Jae In Moon', and 'Chul Su Ahn' as query terms. General terms which are related to presidential election such as 'Presidential Election', 'Proclamation in Support', Public opinion poll' appear frequently. Also the results show specific terms that differentiate each candidate's feature such as 'Park Jung Hee' and 'Yuk Young Su' from the query 'Guen Hae Park', 'a single candidacy agreement' and 'Time of voting extension' from the query 'Jae In Moon' and 'a single candidacy agreement' and 'down contract' from the query 'Chul Su Ahn'. Our system not only extracts 10 topics along with related terms but also shows topics' dynamic changes over time by employing the multinomial Latent Dirichlet Allocation technique. Each topic can show one of two types of patterns-Rising tendency and Falling tendencydepending on the change of the probability distribution. To determine the relationship between topic trends in Twitter and social issues in the real world, we compare topic trends with related news articles. We are able to identify that Twitter can track the issue faster than the other media, newspapers. The user network in Twitter is different from those of other social media because of distinctive characteristics of making relationships in Twitter. Twitter users can make their relationships by exchanging mentions. We visualize and analyze mention based networks of 136,754 users. We put three candidates' name as query terms-Geun Hae Park', 'Jae In Moon', and 'Chul Su Ahn'. The results show that Twitter users mention all candidates' name regardless of their political tendencies. This case study discloses that Twitter could be an effective tool to detect and predict dynamic changes of social issues, and mention-based user networks could show different aspects of user behavior as a unique network that is uniquely found in Twitter.