• Title/Summary/Keyword: causal inference

Search Result 68, Processing Time 0.023 seconds

The Development of A Standardized Test of Science Inquiry Skills : Interpreting and Analyzing Data for Eighth Grade Students (과학 탐구능력 측정을 위한 표준화 검사지 개발 - 중학교 2학년의 자료 분석과 해석 능력을 중심으로 -)

  • Lee, Youne-Woo;Woo, Jong-Ok
    • Journal of The Korean Association For Science Education
    • /
    • v.11 no.1
    • /
    • pp.59-72
    • /
    • 1991
  • This study has formed a clear definition of the elements of inquiry skills : inference, determining relationship, causal explanation, prediction, and created the goals of assessment and the items of assessment. They have been checked the validity and the objectivity and the clarity of the items by six professors of science education. At the same time, the two times of the field trial has been executed. and checked the discriminating power and the difficulty index and the effectiveness of distracters, and modified the items. The test developed in this way was administered to 1060 students of the eighth grade, randomly cluster-sampled from the universe, and standardized. The test is the aptitude test as well as the norm-reference test. and has twenty items. The testing-time is thirty minutes. And the cotent validity is 85%, the objectivity of the answer keys 91.7%, the mean of items difficulty 68.8%, the mean of discriminating power 0.39, the standard deviation 3.31, the reliability(K-R 20) 0.69. Because it is the standardized lest, it can diagnose the well-developed skills and the ill-developed skills of the students, and monitor the development of skills.

  • PDF

Operational Availability Improvement through Online Monitoring and Advice For Emergency Diesel Generator

  • Lee, Jong-Beom;Kim, han-Gon;Kim, Byong-Sub;M. Golay;C.W. Kang;Y. Sui
    • Proceedings of the Korean Nuclear Society Conference
    • /
    • 1998.05a
    • /
    • pp.264-270
    • /
    • 1998
  • This research broadens the prime concern of nuclear power plant operations from safe performance to both economic and safe performance. First emergency diesel generator is identified as one of main contributors for the lost plant availability through the review of plants forced outage records. The framework of an integrated architecture for performing modern on-line condition for operational availability improvement is configured in this work. For the development of the comprehensive sensor networks for complex target systems, an integrated methodology incorporating a structural hierarchy, a functional hierarchy, and a fault-system matrix is formulated. The second part of our research is development of intelligent diagnosis and maintenance advisory system, which employs Bayesian Belief networks (BBNs) as a high level reasoning tool incorporating inherent uncertainty use in probabilistic inference. Our prototype diagnosis algorithms are represented explicitly through topological symbols and links between them in a causal direction. As new evidence from sensor network development is entered into the model especially, our advisory of system provides operational advice concerning both availability and safety, so that the operator is able to determine the likely modes, diagnose the system state, locate root causes, and take the most advantageous action. Thereby, this advice improves operational availability

  • PDF

Gene-Diet Interaction on Cancer Risk in Epidemiological Studies

  • Lee, Sang-Ah
    • Journal of Preventive Medicine and Public Health
    • /
    • v.42 no.6
    • /
    • pp.360-370
    • /
    • 2009
  • Genetic factors clearly play a role in carcinogenesis, but migrant studies provide unequivocal evidence that environmental factors are critical in defining cancer risk. Therefore, one may expect that the lower availability of substrate for biochemical reactions leads to more genetic changes in enzyme function; for example, most studies have indicated the variant MTHFR genotype 677TT is related to biomarkers, such as homocysteine concentrations or global DNA methylation particularly in a low folate diet. The modification of a phenotype related to a genotype, particularly by dietary habits, could support the notion that some of inconsistencies in findings from molecular epidemiologic studies could be due to differences in the populations studied and unaccounted underlying characteristics mediating the relationship between genetic polymorphisms and the actual phenotypes. Given the evidence that diet can modify cancer risk, gene-diet interactions in cancer etiology would be anticipated. However, much of the evidence in this area comes from observational epidemiology, which limits the causal inference. Thus, the investigation of these interactions is essential to gain a full understanding of the impact of genetic variation on health outcomes. This report reviews current approaches to gene-diet interactions in epidemiological studies. Characteristics of gene and dietary factors are divided into four categories: one carbon metabolism-related gene polymorphisms and dietary factors including folate, vitamin B group and methionines; oxidative stress-related gene polymorphisms and antioxidant nutrients including vegetable and fruit intake; carcinogen-metabolizing gene polymorphisms and meat intake including heterocyclic amins and polycyclic aromatic hydrocarbon; and other gene-diet interactive effect on cancer.

A Study on the Automatic Synthesis of Signed Directed Graph Using Knowledge-based Approach and Loop Verification (지식 기반 접근법과 Loop 검증을 이용한 부호운향그래프 자동합성에 관한 연구)

  • Lee Sung-gun;An Dae-Myung;Hwang Kyu Suk
    • Journal of the Korean Institute of Gas
    • /
    • v.2 no.1
    • /
    • pp.53-58
    • /
    • 1998
  • By knowledge-based approach, the SDG(Signed Directed Graph) is automatically synthesized, which is commonly used to represent the causal effects between process variables. Automatic synthesis of SDG is progressed by two steps : (1)inference step uses knowledge base and (2)verification step uses Loop-Verifier. First, Topology and Knowledge Base are constructed by using the information on equipment. And then, Primary-SDG is synthesized by Character Pattern Matching between Variable-Relation-Representation generated by using Topology and Variable-Tendency-Data contained in Knowledge Base. Finally, a modified SDG is made after the Primary-SDG is verified by Loop-Verifier.

  • PDF

Inductive Analysis Approach on Middle Grade Mathematics Pre-Service Teachers' Teaching Philosophies (중등 예비 수학 교사의 교육철학에 대한 귀납적 분석)

  • Han, Sunyoung
    • Journal of Educational Research in Mathematics
    • /
    • v.25 no.4
    • /
    • pp.599-615
    • /
    • 2015
  • Teachers' philosophies have not been emphasized enough in the current teacher education curriculum even though teacher's philosophy palys a critical role in schools and classrooms. The examination on pre-service teachers' teaching philosophies is necessary to improve teacher education curriculum so that teaching philosophies are often discussed in the courses of 'pedagogical content knowledge' as well as 'general education.' Therefore, the current study investigated 44 pre-service teachers' teaching philosophies, their sub domains, and relationships among the sub domains. The previous studies regarding mathematics teacher's teaching philosophy were more about 'teacher's belief' and employed deductive inference approach using surveys or questionnaires. These studies commonly pointed out that there were three major domains of 'belief on mathematics itself,' 'belief on teaching mathematics,' and 'belief on learning mathematics.' As these three domains of teacher's philosophy has been strengthened, there were very few studies examining the other potential domains of teacher's teaching philosophy. According to the findings of the present study, which employed inductive inference approach and pre-service teachers' free essay writing assignment, 'belief on teacher's role in mathematics classroom,' 'belief on the purpose of mathematics education,' and 'motivation to be a mathematics teacher' were additionally illuminated as sub domains of teacher's teaching philosophy. Moreover, the interrelationship among the sub-areas of teacher's teaching philosophy was disclosed. Specifically, 'belief on the purpose of mathematics education' and 'motivation to be a mathematics teacher' influenced the other sub domains. This implies that the relationships among the sub domains of teacher's teaching philosophy were more likely to be causal and vertical relationships rather than independent and parallel relationships. Finally, the findings from the current study provide implications indicating how pre-service teachers' teaching philosophies might be established in mathematics education courses for future research and education.

The Effect of Good and Bad Luck on Reasoning (행운과 불운이 추론에 미치는 효과)

  • Lee, Byung-Kwan;Lee, Guk-Hee
    • Science of Emotion and Sensibility
    • /
    • v.17 no.3
    • /
    • pp.39-48
    • /
    • 2014
  • Good and bad luck is an important factor that frequently affects human information processing. However, in spite of its significance, few studies have been done to examine how good and bad luck influences information processing and reasoning. The current research was performed to explore the effect of good and bad luck on reasoning and, for this, two experiments were conducted. In experiment 1, participants were primed with good or bad luck and were asked to make an inference for a given murder case and include as many as clues for it, while in experiment 2, participants were asked to exclude as many as clues for the same murder case. Results show that, in experiment 1, participants who were primed with good luck included more clues than those who were primed with bad luck. However, in Experiment 2, it was found that participants who were primed with bad luck excluded more clues than those who were primed with good luck. Findings from this study indicate that priming good luck enhances holistic thinking which leads to including more and excluding less clues whereas priming bad luck increases analytic thinking which leads to including less and excluding more clues. Implications of this study for inference and decision making, consumer behavior, and addict psychology are discussed.

Nonstandard Machine Learning Algorithms for Microarray Data Mining

  • Zhang, Byoung-Tak
    • Proceedings of the Korean Society for Bioinformatics Conference
    • /
    • 2001.10a
    • /
    • pp.165-196
    • /
    • 2001
  • DNA chip 또는 microarray는 다수의 유전자 또는 유전자 조각을 (보통 수천내지 수만 개)칩상에 고정시켜 놓고 DNA hybridization 반응을 이용하여 유전자들의 발현 양상을 분석할 수 있는 기술이다. 이러한 high-throughput기술은 예전에는 생각하지 못했던 여러가지 분자생물학의 문제에 대한 해답을 제시해 줄 수 있을 뿐 만 아니라, 분자수준에서의 질병 진단, 신약 개발, 환경 오염 문제의 해결 등 그 응용 가능성이 무한하다. 이 기술의 실용적인 적용을 위해서는 DNA chip을 제작하기 위한 하드웨어/웻웨어 기술 외에도 이러한 데이터로부터 최대한 유용하고 새로운 지식을 창출하기 위한 bioinformatics 기술이 핵심이라고 할 수 있다. 유전자 발현 패턴을 데이터마이닝하는 문제는 크게 clustering, classification, dependency analysis로 구분할 수 있으며 이러한 기술은 통계학과인공지능 기계학습에 기반을 두고 있다. 주로 사용된 기법으로는 principal component analysis, hierarchical clustering, k-means, self-organizing maps, decision trees, multilayer perceptron neural networks, association rules 등이다. 본 세미나에서는 이러한 기본적인 기계학습 기술 외에 최근에 연구되고 있는 새로운 학습 기술로서 probabilistic graphical model (PGM)을 소개하고 이를 DNA chip 데이터 분석에 응용하는 연구를 살펴본다. PGM은 인공신경망, 그래프 이론, 확률 이론이 결합되어 형성된 기계학습 모델로서 인간 두뇌의 기억과 학습 기작에 기반을 두고 있으며 다른 기계학습 모델과의 큰 차이점 중의 하나는 generative model이라는 것이다. 즉 일단 모델이 만들어지면 이것으로부터 새로운 데이터를 생성할 수 있는 능력이 있어서, 만들어진 모델을 검증하고 이로부터 새로운 사실을 추론해 낼 수 있어 biological data mining 문제에서와 같이 새로운 지식을 발견하는 exploratory analysis에 적합하다. 또한probabilistic graphical model은 기존의 신경망 모델과는 달리 deterministic한의사결정이 아니라 확률에 기반한 soft inference를 하고 학습된 모델로부터 관련된 요인들간의 인과관계(causal relationship) 또는 상호의존관계(dependency)를 분석하기에 적합한 장점이 있다. 군체적인 PGM 모델의 예로서, Bayesian network, nonnegative matrix factorization (NMF), generative topographic mapping (GTM)의 구조와 학습 및 추론알고리즘을소개하고 이를 DNA칩 데이터 분석 평가 대회인 CAMDA-2000과 CAMDA-2001에서 사용된cancer diagnosis 문제와 gene-drug dependency analysis 문제에 적용한 결과를 살펴본다.

  • PDF

Exploring Welfare Discourse in Korea Based on M. Foucault's Power And Knowledge Relations (M. Foucault의 권력지식관계론에 기초한 한국의 복지담론 해석)

  • Seo, Jeonghoon
    • Korean Journal of Social Welfare
    • /
    • v.67 no.4
    • /
    • pp.79-101
    • /
    • 2015
  • What is the role of welfare discourse? Michel Foucault suggests the power and knowledge relation that power in a particular society and period controls the society and members by creating knowledge affecting the formation of cognitive and normative systems. Having the formation of exclusions(constraint of cognition), and materiality and reality(normative system) as an analytical framework, this article attempts the exploration of welfare discourse analyses with public statements relating to welfare subjects of the four former Korean presidents. As a result, It is found that dominant epistemic system is formed by balancing welfare and growth and regarding jobs as the best welfare(the linkage of welfare-growth-employment), emphasizing individual economic responsibility and self-reliance, pursuing welfare selectivism, and excluding comprehensive welfare provisions. At the same time, it is observed that power is not always formulating systematic knowledge and that there is a gap between cognition and norm. While the Foucauldian discourse analysis provides a causal inference about low social welfare expenditure, excessive focus on the role of power as knowledge generator and infuser causes a question of how to accommodate contemporary changes into knowledge system.

  • PDF

A Study on Developing a Knowledge-based Database Program for Gas Facility Accident Analysis (가스시설 사고원인 해석을 위한 지식 데이터베이스 프로그램 개발)

  • Kim Min Seop;Im Cha Soon;Lee Jin Han;Park Kyo Shik;Ko Jae Wook
    • Journal of the Korean Institute of Gas
    • /
    • v.4 no.4 s.12
    • /
    • pp.65-70
    • /
    • 2000
  • We develop the database program for accident cause analysis which can help to increase domestic safety custom and prevent recurrence of gas accident and analyze accidents easily The program developed in this study consists of two parts. one part uses accident case database applied if than rule, so it finds root causes by inference of some input values. The other uses Root Cause Analysis Map which divided human errors and equipment difficulties and so we get general root cause by reply some proper questions.

  • PDF

An Exploratory Study on the Structural Relationship of Brand Equity, Internal Brand, Conflict and Relationship Dissolution on Franchise System (프랜차이즈 시스템에서 브랜드 자산, 내부브랜드 활동, 갈등 및 관계해지의 구조적 관계에 관한 탐색적 연구)

  • Kim, Kyung-Min;Na, June-Hee;Lee, Young-Chan
    • Journal of Distribution Research
    • /
    • v.12 no.1
    • /
    • pp.65-84
    • /
    • 2007
  • The relation between franchiser and franchisee participated the franchise system was studied focused on brand for the correlation of relationship dissolution. Basically the relation among brand equity, internal brand, conflict and relationship dissolution based on brand on franchise system were investigated. The study of external factor and internal one of brand recognized by franchisee was conducted. The questionnaire was carried out for franchisee participated of national franchise system. The results showed that the brand external factor of brand transaction cost, brand equity and brand communication had influence on brand dissolution by the affection of brand identification and conflict classified as brand internal factor. In addition, brand internal reinforcement factor affected brand dissolution also. The structural causal inference between internal factor and external one was examined. Finally, the theoretical and managerial insight were suggested on the brand role for the consecutive relation as well as the limit of the study and future suggestion were included.

  • PDF