• Title/Summary/Keyword: biased

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Assessment of Climate Change Impact on Imha-Dam Watershed Hydrologic Cycle under RCP Scenarios (RCP 기후변화 시나리오에 따른 임하댐 유역의 미래 수문순환 전망)

  • Jang, Sun-Sook;Ahn, So-Ra;Joh, Hyung-Kyung;Kim, Seong-Joon
    • Journal of the Korean Association of Geographic Information Studies
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    • v.18 no.1
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    • pp.156-169
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    • 2015
  • This study was to evaluate the RCP climate change impact on hydrological components in the Imha-Dam watershed using SWAT(Soil and Water Assessment Tool) Model. The model was calibrated for six year(2002~2007) and validated for six year(2008~2013) using daily observed streamflow data at three watershed stations. The overall simulation results for the total released volume at this point appear reasonable by showing that coefficient of determination($R^2$) were 0.70~0.85 and Nash-Sutcliffe model efficiency(NSE) were 0.67-0.82 for streamflow, respectively. For future hydrologic evaluation, the HadGEM3-RA climate data by scenarios of Representative Concentration Pathway(RCP) 4.5 and 8.5 of the Korea Meteorological Administration were adopted. The biased future data were corrected using 34 years(1980~2013, baseline period) of weather data. Precipitation and temperature showed increase of 10.8% and 4.9%, respectively based on the baseline data. The impacts of future climate change on the evapotranspiration, soil moisture, surface runoff, lateral flow, return flow and streamflow showed changes of +11.2%, +1.9%, +10.0%, +12.1%, +18.2%, and +11.2%, respectively.

Mutual Adjustment of Oceanographic Measurements from leodo Station and Satellite Data (원격탐사자료와 이어도기지 해양관측자료를 이용한 상호 보정)

  • Kim Chang-Oh;Shim Jae-Seol;Hwang Jong-Sun;Lee Jae-Hak;Kim Soodung;Kim Jeong Woo
    • Korean Journal of Remote Sensing
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    • v.21 no.2
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    • pp.113-120
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    • 2005
  • Oceanographic measurements from Ieodo Ocean Research Station and its vicinity were compared for assessment and mutually adjusted with satellite data. From the Topex/Poseidon and ERS-1/2 radar altimeter and scatterometer data, sea surface height, wind speed and direction were extracted and analyzed. Shipborne wind direction data acquired in June 1995 show good coherence with the satellite data, while sea surface height and wind speed show differences, possibly resulting from the distance between the measurement points. This can be improved by analyzing more satellite data or using other available shipborne data. The recent 3 months of Ieodo Station data between December 2004 and February 2005 were also analyzed and compared with the satellite data. The Ieodo Station data were found to have considerable gaps during the period as well as seriously biased particular when the data were averaged with some abnormal data. The Ieodo Station and satellite data were then mutually adjusted on the basis of their statistics. Ieodo Station oceanographic measurements are very efficient for ground-frothing of satellite data because they are stationary and the station is located far from the coast. On the other hand, the satellite measurements are the only data to fill up gaps and adjust biases of the Ieodo Station data.

An exploratory study on reviewing journal articles of qualitative studies in the field of social welfare in Korea (국내 사회복지질적연구논문 심사의 발전적 방향에 관한 탐색)

  • Chong, Hye-suk;Shim, Woochan
    • Korean Journal of Social Welfare Studies
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    • v.48 no.1
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    • pp.55-89
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    • 2017
  • This study suggests future directions or approaches as to how we should appraise qualitative studies by reviewing previous studies on this topic written in English and published outside of Korea. This study explored experiences and perspectives of qualitative researchers in Korea by conducting a focus group discussion on this topic. Results of this focus group discussion indicated that qualitative researchers often face manuscript reviewers who are overly biased with quantitative paradigm which result in feeling of frustration. They also shared feeling burdened and confused as reviewers due to their own lack of training and preparedness in reviewing qualitative articles. However, participants also stressed the feeling of gratitude and being rewarded because of the experience of mutual growth and partnership with peer qualitative researchers as they strive towards improving the quality and completion of peer researchers' work. Previous studies on this topic included wide range of issues concerning qualitative research appraisal from reflections on the experiences as submitters and reviewers of qualitative studies to academic conceptual papers that discussed researchers' dilemma on research paradigms and qualitative research appraising methods. This study ends with suggestions for the future directions for qualitative researchers in Korea.

An Interpretation on the Philosophy of Mozi School in the Movie Battle of Wits (<묵공>에 반영된 묵가철학의 의의와 한계)

  • Lee, Jong-sung
    • Journal of Korean Philosophical Society
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    • v.137
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    • pp.409-438
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    • 2016
  • The movie, Battle of Wits which is based on the cartoon by Morihideki(森秀樹) is directed by Zhang Zhiliang(張之亮), a director from Hong Kong. Morihideki's cartoon is based on the novel by Sakemikenichi(酒見賢一). The movie represents a successful one-source multi-use case. Battle of wits, which deals with the Mozi's propaganda against war, presents the thought of Mozi School(墨家) in spring, autumn, and warring states. The movie criticizes aggressive war by powerful nations. Aggressive war is an extreme form of brutality and worthless action without any benefit. Aggressive war represents 'never each love(buxiangai, 不相愛)' and 'never each benefit(buxiangli, 不相利)' as understood by Mozi. The main character of the movie endeavors and successfully defends the enemy's attack as Mozi did. It is due to the propaganda of Mozi School 'not to attack(feigong, 非攻)' that they can defend themselves from the attack from a powerful nation. It means that 'the universal love(jianai, 兼愛)', the ideology of Mozi, is concretely actualized. The philosophy of Mozi School in the Battle of Wits has its limits as follows: the thought of Mozi School is just suitable during times of war and unnecessary in times of peace, the contradiction between universal love and hatred for one person; the Mozi School's faith in the nature of human beings to confront betrayal. This limit was also proposed in the movie. However, the movie presented how the masculinity of Mozi School, supplemented by the feminity of Daojia(道家), can succeed in achieving genuine communication. When focusing on this point, the movie can be interpreted as biased towards the philosophy of Daojia.

A Study on Design Optimization of an Axle Spring for Multi-axis Stiffness (다중 축 강성을 위한 축상 스프링 최적설계 연구)

  • Hwang, In-Kyeong;Hur, Hyun-Moo;Kim, Myeong-Jun;Park, Tae-Won
    • Journal of the Korean Society for Railway
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    • v.20 no.3
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    • pp.311-319
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    • 2017
  • The primary suspension system of a railway vehicle restrains the wheelset and the bogie, which greatly affects the dynamic characteristics of the vehicle depending on the stiffness in each direction. In order to improve the dynamic characteristics, different stiffness in each direction is required. However, designing different stiffness in each direction is difficult in the case of a general suspension device. To address this, in this paper, an optimization technique is applied to design different stiffness in each direction by using a conical rubber spring. The optimization is performed by using target and analysis RMS values. Lastly, the final model is proposed by complementing the shape of the weak part of the model. An actual model is developed and the reliability of the optimization model is proved on the basis of a deviation average of about 7.7% compared to the target stiffness through a static load test. In addition, the stiffness value is applied to a multibody dynamics model to analyze the stability and curve performance. The critical speed of the improved model was 190km/h, which was faster than the maximum speed of 110km/h. In addition, the steering performance is improved by 34% compared with the conventional model.

A Study on Building Knowledge Base for Intelligent Battlefield Awareness Service

  • Jo, Se-Hyeon;Kim, Hack-Jun;Jin, So-Yeon;Lee, Woo-Sin
    • Journal of the Korea Society of Computer and Information
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    • v.25 no.4
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    • pp.11-17
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    • 2020
  • In this paper, we propose a method to build a knowledge base based on natural language processing for intelligent battlefield awareness service. The current command and control system manages and utilizes the collected battlefield information and tactical data at a basic level such as registration, storage, and sharing, and information fusion and situation analysis by an analyst is performed. This is an analyst's temporal constraints and cognitive limitations, and generally only one interpretation is drawn, and biased thinking can be reflected. Therefore, it is essential to aware the battlefield situation of the command and control system and to establish the intellignet decision support system. To do this, it is necessary to build a knowledge base specialized in the command and control system and develop intelligent battlefield awareness services based on it. In this paper, among the entity names suggested in the exobrain corpus, which is the private data, the top 250 types of meaningful names were applied and the weapon system entity type was additionally identified to properly represent battlefield information. Based on this, we proposed a way to build a battlefield-aware knowledge base through mention extraction, cross-reference resolution, and relationship extraction.

Population Policy and Population Quality(Report 1. General Review on the Problems of Mental and Physical Handicaps) (인구정책과 인구자질향상을 위한 연구(제 1 보 심신장애자 발생억제대책))

  • Kim, Jong-Kun;Huh, Jung
    • Korea journal of population studies
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    • v.3 no.1
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    • pp.5-41
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    • 1979
  • Vast volumes of studies of the medical and public health aspects of fertility and family planning have been published by the various institutes of health related research and university scholars in Korea. None of them, however, have dealed with the population problems associated with biologically and mentally handicapped people. It must be emphasized that the purpose of Korea's population policy should be to improve the quality of the population rather than to decrease its rate of increase. In this spirit, the first report of this study is to identify problems related with mentally and physically less fitted population, and to attempt to offer the possible solutions to the health planners and policy-makers. Several nation-wide surveys of the handicapped people in Korea have been compared. Each survey shows a wide range of difference in the prevalence of the handicaps(see Table 13). In this study, the data on the handicaps are collected by two independent system ; one by the nation-wide survey and the other by the reporting system existing at the Seoul National University Demonstration Health Project. The Chandrasekar-Deming technique was used to estimate the total number of handicaps. The estimates are summarized in the tables 8, 9 and 10. Estimate of total number of handicapped people in Korea is 601, 400 with the prevalence rate of 16.1 per thousand persons. Even if taking a number of conditions which may result in a biased estimate of the total number of the handicaps into consideration, the proportion of handicapped people in Korea has increased in the past two decade as the result of the rapid decline in fertility and childhood mortality, which consequently prolonged life expectancy of persons with congenital or acquired impediment. An increase in the proportion of handicapped people will eventually bring about serious problems of social welfare, medical care, and population qualities from various aspects including eugenics. To tackle the problem, there must be an increased emphasis on the prevention of handicaps from the government and private sector. Based on the amount and quality of data, and from the practical point of view, this study prepared a set of recommendations for the government to strengthen its programs of the preventive activities during the prenatal period and early childhood, early finding from routine examinations, and proper social and medical rehabilitation.

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Analysis of Trends in Science Gifted Education Using Topic Modeling (토픽 모델링을 활용한 과학영재교육 연구동향 분석)

  • Kim, Hye Won;Jhun, Youngseok
    • Journal of Korean Elementary Science Education
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    • v.40 no.3
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    • pp.283-294
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    • 2021
  • The purpose of this study is to examine the trends of science gifted education-related research for the last 5 years using LDA topic modeling. To achieve the purpose of the study, 2,404 keywords of 292 domestic academic papers were analyzed using RISS, KISS, and DBpia. The main results were as follows. First, the number of researches in science gifted education has been decreasing since 2019. In the science gifted education research, the top 10 keywords were 'students', 'program', 'elementary school', 'class', 'creativity', 'gifted education', 'awareness', 'teacher', 'education', and 'activity'. Second, as a result of topic modeling analysis, 10 topics were derived. Research topics mainly conducted in science gifted education for the past five years are 'Affective characteristics of science gifted students', 'Characteristics of science gifted students in middle school', 'Development and application of science gifted education programs', 'Education programs of science gifted high school', 'Cognitive characteristics of science gifted students', 'Policy of science gifted education', 'Science gifted students and creativity', 'Research conducting education by science gifted students', 'Academic and career choice of science gifted students', 'Science concept of science gifted Students'. In the past, the proportion of specific topics was relatively high, but the proportion between topics does not differ significantly as 2019 approaches. Therefore, it can be confirmed that the more recent it comes, the more research is being conducted evenly without being biased toward one subject.

Deep Learning Model Validation Method Based on Image Data Feature Coverage (영상 데이터 특징 커버리지 기반 딥러닝 모델 검증 기법)

  • Lim, Chang-Nam;Park, Ye-Seul;Lee, Jung-Won
    • KIPS Transactions on Software and Data Engineering
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    • v.10 no.9
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    • pp.375-384
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    • 2021
  • Deep learning techniques have been proven to have high performance in image processing and are applied in various fields. The most widely used methods for validating a deep learning model include a holdout verification method, a k-fold cross verification method, and a bootstrap method. These legacy methods consider the balance of the ratio between classes in the process of dividing the data set, but do not consider the ratio of various features that exist within the same class. If these features are not considered, verification results may be biased toward some features. Therefore, we propose a deep learning model validation method based on data feature coverage for image classification by improving the legacy methods. The proposed technique proposes a data feature coverage that can be measured numerically how much the training data set for training and validation of the deep learning model and the evaluation data set reflects the features of the entire data set. In this method, the data set can be divided by ensuring coverage to include all features of the entire data set, and the evaluation result of the model can be analyzed in units of feature clusters. As a result, by providing feature cluster information for the evaluation result of the trained model, feature information of data that affects the trained model can be provided.

A Study on Photovoltaic Panel Monitoring Using Sentinel-1 InSAR Coherence (Sentinel-1 InSAR Coherence를 이용한 태양광전지 패널 모니터링 효율화 연구)

  • Yoon, Donghyeon;Lee, Moungjin;Lee, Seungkuk
    • Korean Journal of Remote Sensing
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    • v.37 no.2
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    • pp.233-243
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    • 2021
  • Photovoltaic panels are hazardous electronic waste that has heavy metal as one of the hazardous components. Each year, hazardous electronic waste is increasing worldwide and every heavy rainfall exposes the photovoltaic panel to become the source of heavy metal soil contamination. the development needs a monitoring technology for this hazardous exposure. this research use relationships between SAR temporal baseline and coherence of Sentinel-1 satellite to detected photovoltaic panel. Also, the photovoltaic plant detection tested using the difference between that photovoltaic panel and the other difference surface of coherence. The author tested the photovoltaic panel and its environment to calculate differences in coherence relationships. As a result of the experiment, the coherence of the photovoltaic panel, which is assumed to be a permanent scatterer, shows a bias that is biased toward a median value of 0.53 with a distribution of 0.50 to 0.65. Therefore, further research is needed to improve errors that may occur during processing. Additionally, the author found that the change detection using a temporal baseline is possible as the rate of reduction of coherence of photovoltaic panels differs from those of artificial objects such as buildings. This result could be an efficient way to continuously monitor regardless of weather conditions, which was a limitation of the existing optical satellite image-based photovoltaic panel detection research and to understand the spatial distribution in situations such as photovoltaic panel loss.