• Title/Summary/Keyword: Learning Impacts

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Retrieval of Hourly Aerosol Optical Depth Using Top-of-Atmosphere Reflectance from GOCI-II and Machine Learning over South Korea (GOCI-II 대기상한 반사도와 기계학습을 이용한 남한 지역 시간별 에어로졸 광학 두께 산출)

  • Seyoung Yang;Hyunyoung Choi;Jungho Im
    • Korean Journal of Remote Sensing
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    • v.39 no.5_3
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    • pp.933-948
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    • 2023
  • Atmospheric aerosols not only have adverse effects on human health but also exert direct and indirect impacts on the climate system. Consequently, it is imperative to comprehend the characteristics and spatiotemporal distribution of aerosols. Numerous research endeavors have been undertaken to monitor aerosols, predominantly through the retrieval of aerosol optical depth (AOD) via satellite-based observations. Nonetheless, this approach primarily relies on a look-up table-based inversion algorithm, characterized by computationally intensive operations and associated uncertainties. In this study, a novel high-resolution AOD direct retrieval algorithm, leveraging machine learning, was developed using top-of-atmosphere reflectance data derived from the Geostationary Ocean Color Imager-II (GOCI-II), in conjunction with their differences from the past 30-day minimum reflectance, and meteorological variables from numerical models. The Light Gradient Boosting Machine (LGBM) technique was harnessed, and the resultant estimates underwent rigorous validation encompassing random, temporal, and spatial N-fold cross-validation (CV) using ground-based observation data from Aerosol Robotic Network (AERONET) AOD. The three CV results consistently demonstrated robust performance, yielding R2=0.70-0.80, RMSE=0.08-0.09, and within the expected error (EE) of 75.2-85.1%. The Shapley Additive exPlanations(SHAP) analysis confirmed the substantial influence of reflectance-related variables on AOD estimation. A comprehensive examination of the spatiotemporal distribution of AOD in Seoul and Ulsan revealed that the developed LGBM model yielded results that are in close concordance with AERONET AOD over time, thereby confirming its suitability for AOD retrieval at high spatiotemporal resolution (i.e., hourly, 250 m). Furthermore, upon comparing data coverage, it was ascertained that the LGBM model enhanced data retrieval frequency by approximately 8.8% in comparison to the GOCI-II L2 AOD products, ameliorating issues associated with excessive masking over very illuminated surfaces that are often encountered in physics-based AOD retrieval processes.

The Analysis on the Relationship between Firms' Exposures to SNS and Stock Prices in Korea (기업의 SNS 노출과 주식 수익률간의 관계 분석)

  • Kim, Taehwan;Jung, Woo-Jin;Lee, Sang-Yong Tom
    • Asia pacific journal of information systems
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    • v.24 no.2
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    • pp.233-253
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    • 2014
  • Can the stock market really be predicted? Stock market prediction has attracted much attention from many fields including business, economics, statistics, and mathematics. Early research on stock market prediction was based on random walk theory (RWT) and the efficient market hypothesis (EMH). According to the EMH, stock market are largely driven by new information rather than present and past prices. Since it is unpredictable, stock market will follow a random walk. Even though these theories, Schumaker [2010] asserted that people keep trying to predict the stock market by using artificial intelligence, statistical estimates, and mathematical models. Mathematical approaches include Percolation Methods, Log-Periodic Oscillations and Wavelet Transforms to model future prices. Examples of artificial intelligence approaches that deals with optimization and machine learning are Genetic Algorithms, Support Vector Machines (SVM) and Neural Networks. Statistical approaches typically predicts the future by using past stock market data. Recently, financial engineers have started to predict the stock prices movement pattern by using the SNS data. SNS is the place where peoples opinions and ideas are freely flow and affect others' beliefs on certain things. Through word-of-mouth in SNS, people share product usage experiences, subjective feelings, and commonly accompanying sentiment or mood with others. An increasing number of empirical analyses of sentiment and mood are based on textual collections of public user generated data on the web. The Opinion mining is one domain of the data mining fields extracting public opinions exposed in SNS by utilizing data mining. There have been many studies on the issues of opinion mining from Web sources such as product reviews, forum posts and blogs. In relation to this literatures, we are trying to understand the effects of SNS exposures of firms on stock prices in Korea. Similarly to Bollen et al. [2011], we empirically analyze the impact of SNS exposures on stock return rates. We use Social Metrics by Daum Soft, an SNS big data analysis company in Korea. Social Metrics provides trends and public opinions in Twitter and blogs by using natural language process and analysis tools. It collects the sentences circulated in the Twitter in real time, and breaks down these sentences into the word units and then extracts keywords. In this study, we classify firms' exposures in SNS into two groups: positive and negative. To test the correlation and causation relationship between SNS exposures and stock price returns, we first collect 252 firms' stock prices and KRX100 index in the Korea Stock Exchange (KRX) from May 25, 2012 to September 1, 2012. We also gather the public attitudes (positive, negative) about these firms from Social Metrics over the same period of time. We conduct regression analysis between stock prices and the number of SNS exposures. Having checked the correlation between the two variables, we perform Granger causality test to see the causation direction between the two variables. The research result is that the number of total SNS exposures is positively related with stock market returns. The number of positive mentions of has also positive relationship with stock market returns. Contrarily, the number of negative mentions has negative relationship with stock market returns, but this relationship is statistically not significant. This means that the impact of positive mentions is statistically bigger than the impact of negative mentions. We also investigate whether the impacts are moderated by industry type and firm's size. We find that the SNS exposures impacts are bigger for IT firms than for non-IT firms, and bigger for small sized firms than for large sized firms. The results of Granger causality test shows change of stock price return is caused by SNS exposures, while the causation of the other way round is not significant. Therefore the correlation relationship between SNS exposures and stock prices has uni-direction causality. The more a firm is exposed in SNS, the more is the stock price likely to increase, while stock price changes may not cause more SNS mentions.

A Qualitative Study on Lived Experiences of Children Who Live in a Poor Neighborhood -"Hard Life in Our Village"- (빈곤지역아동의 거주체험에 대한 질적 연구 - 우리 동네살이 -)

  • Kim, Kyung-Hee;Kim, Sun-Min;Park, Keon-Hye
    • Korean Journal of Social Welfare
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    • v.63 no.3
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    • pp.109-131
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    • 2011
  • This qualitative study aimed to explore and understand the impacts of the poor neighborhood on children from their own perspectives. To this end, the meaning and the structure of children's lived experiences were explored. The participants were recruited from elementary school high grade students living in poor neighborhood. Focused group interviews were conducted in each of the 24 World Visions social work agencies. The collected data were analysed qualitatively. According to the results, the following main themes could be extracted from the children's lived experiences: "Conflict between connection and differentiation", "Resigning to the fate of being neglected in danger" "Learning to live in the dark cave", "Anticipating a bowl of trust from the neighborhood". The children living in poor neighborhood were threatened by the physical and emotional danger highly probable in weak social infrastructure. Also, they have internalized negative self-identity by chaotic environment and, even the negative role models from alcoholic and sometimes violent adults. However, they were experiencing positive caring from and solidarity with surrounding neighborhood, and were participating in volunteered activities for asserting their citizen rights. These may be the keys to empowerment and, ultimately, to change for themselves and the community. The implications of the study results for the policy making and the actual practice were discussed focusing on the children's rights and well-being.

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인터넷을 이용한 육상물류중개시스템 개발에 관한 연구

  • 박남규;최형림;송근곤;박영재;손형수
    • Proceedings of the Korea Database Society Conference
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    • 1999.06a
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    • pp.335-345
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    • 1999
  • 오늘날 날로 증가하는 물류비는 개별 기업은 물론 국가 전체의 수출 경쟁력을 약화시키는 주요 원인으로 지적되고 있다. 그러나 그동안 우리나라에서는 물류비 절감을 위한 종합적이고 체계적인 대책이 이루어지지 못하였다. 특히 본 논문의 연구대상인 육상물류의 경우 그 비중이 전체 화물 운송의 60% 이상을 차지함에도 불구하고 심각한 교통체증 및 물류기반 시설의 미비, 효율적인 정보시스템의 미비 등으로 인하여 물류비가 계속 증가하는 양상을 보여 왔다. 따라서 본 논문에서는 우리나라 육상물류시스템이 안고 있는 문제점의 해결을 위한 방안들 중의 하나로 정보기술의 활용에 관한 내용을 다루고 있다. 즉 영세한 기업들도 누구나 손쉽게 이용할 수 있도록 인터넷을 이용한 육상물류중개시스템의 개발에 관한 내용을 소개하고 있다. 육상물류중개시스템은 복합화물주선업체인 (주) 대형물류와 함께 개발한 시스템으로 인터넷을 통하여 화주의 화물 운송의뢰를 접수받아 이를 여러 운송업체에게 제공해주는 역할을 수행하게 된다. 특히 육상물류중개시스템은 화물의 운송과 관련하여 발생하는 다양한 정보들을 데이터베이스에 저장하여 두었다가 세관을 비롯한 터미날에 대한 각종 신고업무에 이용할 수 있으며, 이밖에도 교통정보 및 화물 위치정보 등 다양한 서비스를 제공해줄 수 있다. 따라서 운송업체의 공차율을 줄이고 화주에게는 자신의 화물에 대한 정보를 실시간으로 전달해 줄 수 있다는 장점이 있다. 또한 이러한 육상물류중개시스템은 현재 개발중인 통합데이터베이스를 기반으로 한 항만물류원스톱서비스 시스템과 연계되어 차후에는 물류원스톱시스템으로 발전할 수 있을 것이다. 연구가 진행되고 있는 인공신경망과의 모형결합을 통해 기존연구와는 다른 새로운 통합예측방법론을 제시하고자 한다. 본 연구에서 제시하는 통합방법론은 크게 2단계 과정을 거쳐 예측모형으로 완성이 된다. 즉, 1차 모형단계에서 원시 재무시계열은 먼저 웨이블릿분석을 통해서 노이즈가 필터링 되는 동시에, 과거 재무시계열의 프랙탈 구조, 즉 비선형적인 움직임을 보다 잘 반영시켜 주는 다차원 주기요소를 가지는 시계열로 분해, 생성되며, 이렇게 주기에 따라 장단기로 분할된 시계열들은 2차 모형단계에서 신경망의 새로운 입력변수로서 사용되어 최종적인 인공 신경망모델을 구축하는 데 반영된다.ocioeconomic impacts are resulted from the program. It would be useful for the means of (ⅰ) fulfillment of public accountability to legitimate the program and to reveal the expenditure of pubic fund, and (ⅱ) managemental and strategical learning to give information necessary to improve the making. program and policy decision making, The objectives of the study are to develop the methodology of modeling the socioeconomic evaluation, and build up the practical socioeconomic ev

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Impact of Social Networking Service on the Team Cooperation, Quality of Decision Making and Job Performance (SNS의 사용이 팀의 협력과 의사결정의 질 및 업무성과에 미치는 영향)

  • Kim, Yoon-Mi;Chung, Dong-Seop
    • Journal of Korea Multimedia Society
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    • v.17 no.2
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    • pp.180-190
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    • 2014
  • Social network services are increasingly being used in organizational settings to improve relationships among employees and enhance prospects for information exchange and cooperative work. Social Networking Service(SNS) has deeply penetrated organizational job settings, influencing multiple aspects of employee's life. This study is designed to explore the impact of SNS engagement on the job performance mediated as team cooperation and decision making quality effects. Data were collected from 146 employees who use organizational SNS in there company. Factor analysis and structural equation method are employed. Results from a survey accompanied by the substantial impacts of organizational employee's social networking engagement on social learning processes and outcomes. SNS engagement not only directly influences organizational employee's job performance, but also helps their team cooperation and decision making quality from others and adapt to organizational culture, both of which play prominent roles in improving their job performance.

The Effects of Innovator's DNA on the Innovative Strategy in SMEs (중소기업 경영자의 혁신DNA와 혁신전략에 관한 연구)

  • Kim, Seung Ho;Bae, Seung Hyun;Jun, In;Park, Jong Ho;Son, Kang Ho
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.9 no.6
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    • pp.199-212
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    • 2014
  • Recently, there are increasing to the interest in the organizational innovation DNA as the innovation origin and these interest mainly were approached through the case analysis of global innovative companies. The purpose of study is to investigate the applicability under the CEO of SMEs settings as global companies' cases. The research focused on the impact of innovator's DNA on innovative strategy by the empirical study that analyzed from 110 firm's data in Daegu and Gyeongbuk region. The results of empirical study, innovator's DNA has positive effects on the overall innovative strategy, especially the effects of discovery DNA are stronger than operational DNA. Included to the discovery DNA effects, operational DNA bring about negative on the product differentiation, though it has positive on the market differentiation. In terms of components of innovator's DNA, the questioning and association have strong impacts on the overall innovative strategy, and analyzing has positive on market differentiation, but specific task implementation has negative on the product differentiation. The results suggest that the logic of global innovation case is possible to the SME's CEO and need to learning efforts to promote discovery DNA for successful innovation.

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Impacts of Buyer-Supplier Cooperation on Trust and Performance: Moderating Role of Governance Mechanism (구매자와 공급자 간 협력활동이 신뢰 및 성과에 미치는 영향: 거버넌스의 조절효과를 중심으로)

  • Kim, Kyung-Tae;Hui, Liang;Lee, Jung-Seung
    • Journal of Distribution Science
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    • v.14 no.8
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    • pp.113-121
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    • 2016
  • Purpose - This paper aims to examine the impact of buyer-supplier cooperation on suppliers' trust on buyers and the moderating role of buyers' governance mechanism between the sharing activities and trust. Research design, data, and methodology - An integrated research model is designed to materialize the research hypotheses. First, the impact of buyer-supplier cooperation is empirically analyzed by looking into how the sharing activities, in the field of information, resource, and knowledge, of buyer with supplier will affect the trust of supplier on buyer. Second, the moderating effect of contract-based governance mechanism of buyer is empirically analyzed. Third, the influence of trust on innovation performance of suppler is empirically analyzed. Results - Our findings provide supporting evidence for some of our hypotheses. First, all of the sharing activities are significantly influential, but in different degree, to trust of supplier. Second, contract-based governance mechanism of buyer have a moderating effect on the relationship between sharing activities and trust, positively in resource-sharing activities, negatively in information-sharing activities, not significant in knowledge-sharing activities. Third, supplier's trust on buyer positively affects supplier's own innovation performance. Conclusions - The strategies applied in supply chain management have become important as the competition among firms has shifted from competition between individual firms to competition between supply chains. A customer's sharing activities with its supplier may contribute to an increase in innovation performance. The supplier's information-sharing activity with its customer could affect its information-sharing activities with its main supplier. Cooperative activity with a partner in the supply chain is cultivated and amassed into relationship knowledge, and this study shows that the cooperative relational knowledge related to information-sharing activities enables firms to participate in sharing activities with their main suppliers. Increasing evidence shows that sharing various activities between buyer and supplier improves trust and performance outcomes, and enables firms to maintain competitive advantage. From the perspective of knowledge theory, external knowledge is becoming more important in firms' innovation activities, because innovative knowledge is acquired primarily through interaction with another organization. In addition, relationship learning could be an important tool in absorbing the supplier's core technology, information, expertise, and core competencies, increasing relational value.

Cities as Place for Climate Mitigation and Adaptation: A Case Study of Portland, Oregon, USA (기후완화와 적용의 장소로서의 도시 - 미국 오레건주 포트랜드시 사례연구 -)

  • Chang, Hee-Jun;House-Peters, Lily
    • Journal of the Korean Geographical Society
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    • v.45 no.1
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    • pp.49-74
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    • 2010
  • Cities are major sources of greenhouse gas emissions but also suitable places for implementing proactive climate mitigation and adaptation strategies. Based on the interdisciplinary review of literature, we categorize the current discussion about urban climate mitigation and adaptation planning, policy and practices into four perspectives - sustainability science, global change science, multilevel governance, and structural engineering. While these four schools of thought have distinct perspectives rooted in different disciplinary lenses, our synthesis of the literature identifies several universal themes that are common to all of the perspectives in the context of combating threats posed by climate change. The Portland case study illustrates that a city can make changes to reduce greenhouse gas emissions and increase adaptive capacity to climate change impacts by implementing smart growth, devising local climate action plans that target emission reductions in various sectors, recognizing the interactions and influences of multiple scales of governance, and supporting the installation of various green infrastructures that contribute to green economy. Furthermore, a university can serve as a hub in this climate mitigation and adaptation arena by connecting various levels of community organizations in both public and private sectors, creating innovative research centers and spatially explicit green infrastructure, designing impact assessments and campus carbon inventories, and engaging students and the larger community through service learning.

A Study on Curriculum Guidelines for Computer Education based on the analysis of Status Quo in IT Advanced Countries (해외 주요국의 현황 분석에 기초한 우리나라 컴퓨터교육의 교육과정 방향)

  • Kim, Mi-Ryang
    • The Journal of Korean Association of Computer Education
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    • v.8 no.3
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    • pp.43-60
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    • 2005
  • Teaching computer and ICT skills in K-12 helps to bridge the digital divide of the students at the minimum cost, and provides them with a chance of getting a Quality of life as well as a Quality of work in the future. From examining the education policies of U.S., EU, Canada, and other countries, concerning computer education, several factors, including vision and national-level policy, Quality of manpower, needs for computer-related technology, structure of IT industry, overall demand for IT specialists, have been identified as those with major impacts on the curriculum of computer education. Based upon the analysis of domestic key factors, three levels of computer education program are suggested. At the most basic and least controversial level, basic ICT-skill program for effective learning needs to be provided for every student. Next level is concerned with improving the Quality of life and work. A program for introductory level of computer science can be provided as extra-curricular classes for bright and eager students, who might want to be computer expert or specialists.

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Middle School Students' Perceptions and Practice of Handwriting and Factors Affecting their Attitudes towards Handwriting (중학생의 필기에 대한 인식, 실태 및 필기태도에 영향을 미치는 요인들)

  • Jeong, Min-Seon;Shin, Namin
    • The Journal of the Korea Contents Association
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    • v.14 no.10
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    • pp.416-428
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    • 2014
  • This study aimed to identify middle school students' perceptions and practices of handwriting, and factors affecting their attitudes towards handwriting. Data were collected by means of a survey targeting 346 students enrolled in 9 middle schools(Male=172, Female=172, Unknown=2, M=13.5 years old, SD= .94). Interviews, too, were conducted with 12 students in order to identify the students' perceptions of handwriting. The analyses of both survey and interview data revealed the following: (1) the majority of the interviewee students believed that handwriting is useful for memory and summarization so as to get a better school grade, including performance evaluations; (2) Many of the interviewee students were unsatisfied with their handwriting skills, giving higher scores to their peers' handwriting; (3) 45.7% of the students reported that mother was the one who taught them how to write for the first time; and 49.7% of them had no learning experience of taking notes; (4) Girls than boys and 1st graders than 2 or 3 graders showed more positive attitude towards handwriting; and (5) A multiple regression analysis showed that all the variables entered in the regression model, including sex, grade, affective attitude toward hands-on activities, physical abilities, time spent using a computer, and perceptions of Korean characters, had significant impacts on the students' attitudes towards handwriting.