• Title/Summary/Keyword: Explicit/Implicit Program

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Influence of Various Parameter for Nonlinear Finite Element Analysis of FRP-Concrete Composite Beam Using Concrete Damaged Plasticity Model (콘크리트 손상 소성모델을 이용한 FRP-콘크리트 합성보의 비선형 유한요소해석에서 여러 변수들의 영향)

  • Yoo, Seung-Woon;Kang, Ga-Ram
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.2
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    • pp.697-703
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    • 2017
  • This paper examines the flexure behavior of FRP-concrete composite structure that can replace conventional reinforced concrete structure types. In order to investigate the structural performance and behavioral characteristics in numerical analysis means, ABAQUS, a general purpose finite element analysis program, was utilized for nonlinear finite element analysis, and the various variables and their influences were analyzed and compared with experimental results to suggest values optimized to this composite structure. The concrete damage plasticity model and Euro code for concrete were used. In the implicit finite element analysis, the convergence was ambiguous when geometrical and material nonlinearity were large, so the explicit finite element analysis used in this study was deemed to be appropriate. From the comparison with the experiment about concrete damaged plasticity model, 20mm for the mesh size, $30^{\circ}$ for the dilation angle, $100Nmm/mm^2$ for the value of fracture energy, 0.667 for Kc value, and the consideration of damage parameter were suggested believed to be appropriate. The numerical model suggested in this study was able to imitate the ultimate load and cracking pattern very well; therefore, it is expected to be utilized in research of various new material composite structures.

Development and Application of NOS Education Program according to Analyzing the Characteristics of Nature of Science(NOS) in Exhibits of Science Museum (국내 과학관 전시물에 반영된 과학의 본성(NOS) 특징 분석에 따른 프로그램 개발 및 이의 적용)

  • Park, Young-Shin;Yu, Jiyeon
    • Journal of the Korean Society of Earth Science Education
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    • v.10 no.2
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    • pp.104-121
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    • 2017
  • The purpose of this study is to identify the status of the science museum reflected in the exhibition, and develop and apply Nature of Science(NOS) education programs based on the science museum exhibition. The analyse tool was developed to understand the NOS in the science museum. The researchers recognized the nature of science reflected in four exhibition halls in Korea. Based on the analysis, we developed the NOS education program. NOS education programs were developed and applied to supplement the NOS that appears to be limited to scientific exhibitions based on the prior analysis of science exhibition. The results of the study were as follows. First, we analyzed the nature of science reflected in the exhibition of two main science museums, and it was mostly implicit and most were to understand the relationship among STS(Science-Technology-Society). And also we analyzed the NOS reflected in the exhibition of two national history museum, and it was also mostly implicit and most were about the way of how to find out the knowledge, inference. Second, in order to supplement the NOS of the science museum, we developed the NOS education program based on the exhibits. After applying it to the science museum, we conducted a qualitative study. As a result, there was a positive change only in the aspects of NOS (science is tentative, science is from creativity and imaginative, science is the produce of social and culture, science is from the scientific method) that reflected explicitly. The conclusions derived from this study are as follows : For the cultivation of science in the scientific museum, various factors are needed depending on the theme of the science museum. Also, it is helpful to actively implement the NOS educational programs that utilize the exhibit. Therefore, the exhibit planners' and developers' competencies are critical to develop explicit NOS education programs in its expertise.

Integration of Ontology Open-World and Rule Closed-World Reasoning (온톨로지 Open World 추론과 규칙 Closed World 추론의 통합)

  • Choi, Jung-Hwa;Park, Young-Tack
    • Journal of KIISE:Software and Applications
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    • v.37 no.4
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    • pp.282-296
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    • 2010
  • OWL is an ontology language for the Semantic Web, and suited to modelling the knowledge of a specific domain in the real-world. Ontology also can infer new implicit knowledge from the explicit knowledge. However, the modeled knowledge cannot be complete as the whole of the common-sense of the human cannot be represented totally. Ontology do not concern handling nonmonotonic reasoning to detect incomplete modeling such as the integrity constraints and exceptions. A default rule can handle the exception about a specific class in ontology. Integrity constraint can be clear that restrictions on class define which and how many relationships the instances of that class must hold. In this paper, we propose a practical reasoning system for open and closed-world reasoning that supports a novel hybrid integration of ontology based on open world assumption (OWA) and non-monotonic rule based on closed-world assumption (CWA). The system utilizes a method to solve the problem which occurs when dealing with the incomplete knowledge under the OWA. The method uses the answer set programming (ASP) to find a solution. ASP is a logic-program, which can be seen as the computational embodiment of non-monotonic reasoning, and enables a query based on CWA to knowledge base (KB) of description logic. Our system not only finds practical cases from examples by the Protege, which require non-monotonic reasoning, but also estimates novel reasoning results for the cases based on KB which realizes a transparent integration of rules and ontologies supported by some well-known projects.

The Learning Experience of 7th Graders on NOS (Nature of Science) as a Process in Research-Based "Becoming a Scientist" Mentor-mentee Program (중학생의 "과학자 되어보기" 멘토-멘티 프로그램 참여를 통한 과정으로서 과학의 본성 학습 경험)

  • Jung, Chan-Mi;Shin, Dong-Hee
    • Journal of The Korean Association For Science Education
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    • v.35 no.4
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    • pp.629-648
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    • 2015
  • This study is a case study examining how research-based 'authentic' science education program contextually facilitates students' learning on NOS as a process. We developed 'Becoming a Scientist' mentor-mentee program and applied it to six Korean 7th graders for 8 months. A mentor, who is also a researcher, provided scaffolding and coaching, and her mentees were to perform the whole process of science research, including selecting the research subject and questions, planning research design, doing experiments, collecting and analysing data, writing research paper, and experiencing poster presentation at an academic conference. The research questions are 1) What would the students experience at every step of their research process?, and 2) Which perceptions would they construct NOS as a process? Data include classroom observations, interview, mentor's journal, and students' learning products. The results show that the mentees have experienced their views of NOS as a process in various ways such as role of research question and purpose, validity of measured value, researcher's subjectivity in interpreting data, experience of making public and peer review, and significance of academic conference. This study has shown that students' actual experience in scientific research enhanced their views about NOS as process without explicit and reflective approaches. We defined 'authenticity' associated with not only with its similarity to what scientists do but to learner's identity as scientific researcher. Based on the situated learning theory, this study sheds light on the necessity of reconsideration about the meaning of authenticity and embodying authentic context in science education for better NOS learning.

Effects of SSI Argumentation Program based on SEL for Preservice Biology Teachers (예비 생물교사를 위한 사회정서학습에 기반한 SSI 논증 프로그램 적용 효과 탐색)

  • Kim, Sun Young;Kim, Su Hyeon
    • Journal of The Korean Association For Science Education
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    • v.38 no.2
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    • pp.259-271
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    • 2018
  • This study examined the effect of the SSI argumentation program based on social and emotional learning(SEL). The program consisted of 3 stages: (1) express their own feelings about SSI, identify the issues of SSI, and define a goal; (2) think of many possible solutions and envision results through argumentation; (3) select the best solution and make a decision based on warrants, data, and rebuttals. In each stage, the social-emotional strategies of self-awareness, self-management, social-awareness, relationship-management, and responsible decision making were used. Seventeen preservice biology teachers participated in this study during one semester dealing with four socioscientific issues. The results indicated that the preservice teachers, as time went on, became accustomed to expressing identifiable rebuttals, dispute talk, and asking questions. At the first SSI argumentation, argumentation mainly consisted of cumulative talk with no rebuttals, representing level 2 argumentation. Level 3 argumentation represented rebuttals that were implicit and weak, with cumulative talk. In level 2 and 3 argumentation, the preservice teachers represented understanding of others and compassion for self and others. Level 4 argumentation had rebuttals that were explicit, asking critical questions of the opposite sides. In addition, level 5 argumentation represented more than two controversial points with several instances of dispute talk. In levels 4 and 5, the preservice teachers became actively engaged in communication, inquiry self with others, managing vulnerability and negotiation.