• Title/Summary/Keyword: progression

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The Development and Validation of Learning Progression for Solar System Structure Using Multi-tiers Supply Form Items (다층 서답형 문항을 이용한 태양계 구조 학습 발달과정 개발 및 타당성 검증)

  • Oh, Hyunseok;Lee, Kiyoung
    • Journal of the Korean earth science society
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    • v.41 no.3
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    • pp.291-306
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    • 2020
  • In this study, we developed a learning progression for the structure of the solar system using multi-tier supply form items and validated its appropriateness. To this end, by applying Wilson's (2005) construct modeling approach, we set up 'solar system components,' 'size and distance pattern of solar system planets,' and 'solar system modeling' as the progress variables of the learning progression and constructed multi-tier supply form items for each of these variables. The items were applied to 150 fifth graders before and after the classes that dealt with the 'solar system and star' unit. To describe the results of the assessment, the students' responses to each item were categorized into five levels. By analyzing the Wright map that was created by applying the partial credit Rasch model, we validated the appropriateness of the learning progression based on the students' responses. In addition, the validity of the hypothetical pathway that was established in the learning progression was verified by tracking changes in the developmental level of students before and after the classes. The results of the research are as follows. The bottom-up research method that used multi-tier supply form items was able to elaborately set the empirical learning progression for the conceptualization of the structure of the solar system that is taught in elementary school. In addition, the validity of the learning progression was high, and the development of students was found to change with the learning progression.

Learning Progressions and Teacher Education: A Developmental Approach for Improving Teachers' Expertise in Integrating ICT (학습순행과 교사교육: 초임 교사의 ICT 통합 전문성 향상을 위한 발달적 접근)

  • Kim, Hye-Jeong
    • 한국정보교육학회:학술대회논문집
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    • 2010.08a
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    • pp.151-160
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    • 2010
  • Learning progression is an advantageous way to describe the development of learner understanding about a topic. In the present study, learning progression is introduced to characterize novice teachers' professional knowledge and competence and to help designing teacher professional development programs in the developmental approach. The development and validation phases of learning progression are proposed in the paper. In addition a case study is presented to demonstrate the process of developing a learning progression for teaching-through-inquiry using ICT. The learning progression in novice teacher professional development can be used to assess the level of teacher understanding in specific topic and to effectively support the development of teachers' professional knowledge and competence via professional development programs in the longitudinal view.

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A Case Study for Exploring Topic-Specific PCK Progression on Elementary Teachers' Instruction of 'Earth Revolution' (지구 공전에 대한 초등 교사들의 주제-특이적 PCK 발달과정 탐색을 위한 사례 연구)

  • Lee, Jeong-A;Lee, Kiyoung
    • Journal of Korean Elementary Science Education
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    • v.36 no.4
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    • pp.405-427
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    • 2017
  • This study aims to describe various teaching cases about 'earth revolution' in terms of PCK; knowledge of curriculum, knowledge of teaching strategies and knowledge of assessment. Based on these various cases we suggested PCK progressions about 'earth revolution'. For these, we recorded 'solar system and star' classes of nine elementary school teachers' in Kangwon, Gyeonggi, Gwangju, and Seoul. We adopted Lee & Lee (2016)'s topic-specific PCK framework to analyze the classes. As results, we suggested topic-specific PCK progression about 'earth revolution'. The results showed the upper anchor of the earth revolution class were exploring the reason of the change of constellation, finding the tendency of constellation change. These teachings were carried by the teachers' adaptive strategies. The upper anchor of the assessment was monitoring students' understanding during the whole class. The PCK progression about 'earth revolution' could help the teachers plan the earth revolution class, and reflect their own teachings.

Surgical Results of Intramedullary Spinal Cord Ependymomas in Adults : Retrospective Analysis of 51 Cases

  • Son, Young-Je;Chung, Chun-Kee;Kim, Hyun-Jib
    • Journal of Korean Neurosurgical Society
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    • v.40 no.3
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    • pp.164-168
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    • 2006
  • Objective : The goal of treatment for spinal cord ependymoma is complete removal without postoperative neurological deficit. The authors analyzed the surgical results and factors influencing the postoperative prognosis. Methods : Fifty-one cases of primary spinal cord ependymoma, surgically treated between 1979 and 2003, were retrospectively analyzed. The mean follow-up period was 44 months. Results : Gross total removal was achieved in 42 patients and incomplete removal in nine. The proportion of complete surgical removals was influenced by tumor location and histology. Disease progression was observed in five cases [9.8%], the mean progression free interval after surgical removal was 48 months and the 5-year progression free rate was 68%. Disease progression was found in none of the 42 cases who underwent complete removal, and in 5 of 9 cases who hadincomplete removal group [P<0.001]. Statistically significant disease-progression factors by multivariate analysis were the surgical extent of removal [P=0.012]. preoperative functional status [P=0.032] the presence of intratumoral cysts [P=0.007] and postoperative radiation therapy [P=0042]. Of those patients who underwent incomplete removal, radiation therapy was found to significantly improve the clinical result [P=0042]. Conclusion : In the surgical treatment of spinal cord ependymoma, preoperative functional status, the presence of intratumoral cysts, the extent of removal, and postoperative radiation therapy were found to be significant prognostic factors of postoperative outcome.

COMPASS - New modeling and simulation approach to PWR in-vessel accident progression

  • Podowski, Michael Z.;Podowski, Raf M.;Kim, Dong Ha;Bae, Jun Ho;Son, Dong Gun
    • Nuclear Engineering and Technology
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    • v.51 no.8
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    • pp.1916-1938
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    • 2019
  • The objective of this paper is to discuss the modeling principles of phenomena governing core degradation/melting and in-vessel melt relocation during severe accidents in light water reactors. The proposed modeling approach has been applied in the development of a new accident simulation package, COMPASS (COre Meltdown Progression Accident Simulation Software). COMPASS can be used either as a stand-alone tool to simulate in-vessel meltdown progression up to and including RPV failure, or as a component of an integrated simulation package being developed in Korea for the APR1400 reactor. Interestingly, since the emphasis in the development of COMPASS modeling framework has been on capturing generic mechanistic aspects of accident progression in light water reactors, several parts of the overall model should be useful for future accident studies of other reactor designs, both PWRs and BWRs. The issues discussed in the paper include the overall structure of the model, the rationale behind the formulation of the governing equations and the associated simplifying assumptions, as well as the methodology used to verify both the physical and numerical consistencies of the overall solver. Furthermore, the results of COMPASS validation against two experimental data sets (CORA and PHEBUS) are shown, as well as of the predicted accident progression at TMI-2 reactor.

Thermal Hydraulic Design Parameters Study for Severe Accidents Using Neural Networks

  • Roh, Chang-Hyun;Chang, Soon-Heung
    • Proceedings of the Korean Nuclear Society Conference
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    • 1997.10a
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    • pp.469-474
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    • 1997
  • To provide tile information ell severe accident progression is very important for advanced or new type of nuclear power plant (NPP) design. A parametric study, therefore was performed to investigate the effect of thermal hydraulic design parameters ell severe accident progression of pressurized water reactors (PWRs), Nine parameters, which are considered important in NPP design or severe accident progression, were selected among the various thermal hydraulic design parameters. The backpropagation neural network (BPN) was used to determine parameters, which might more strongly affect the severe accident progression, among mile parameters. For training. different input patterns were generated by the latin hypercube sampling (LHS) technique and then different target patterns that contain core uncovery time and vessel failure time were obtained for Young Gwang Nuclear (YGN) Units 3&4 using modular accident analysis program (MAAP) 3.0B code. Three different severe accident scenarios, such as two loss of coolant accidents (LOCAs) and station blackout(SBO), were considered in this analysis. Results indicated that design parameters related to refueling water storage tank (RWST), accumulator and steam generator (S/G) have more dominant effects on the progression of severe accidents investigated, compared to tile other six parameters.

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Genetic Abnormalities in Oral Leukoplakia and Oral Cancer Progression

  • Kil, Tae Jun;Kim, Hyun Sil;Kim, Hyung Jun;Nam, Woong;Cha, In-Ho
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.6
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    • pp.3001-3006
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    • 2016
  • Background: The cancer progression of oral leukoplakia is an important watchpoint in the follow-up observation of the patients. However, potential malignancies of oral leukoplakia cannot be estimated by histopathologic assessment alone. We evaluated genetic abnormalities at the level of copy number variation (CNV) to investigate the risk for developing cancer in oral leukoplakias. Materials and Methods: The current study used 27 oral leukoplakias with histological evidence of dysplasia. The first group (progressing dysplasia) consisted of 7 oral lesions from patients with later progression to cancer at the same site. The other group (non-progressing dysplasia) consisted of 20 lesions from patients with no occurrence of oral cancer and longitudinal follow up (>7 years). We extracted DNA from Formalin-Fixed Paraffin-Embedded (FFPE) samples and examined chromosomal loci and frequencies of CNVs using Taqman copy number assays. Results: CNV frequently occurred at 3p, 9p, and 13q loci in progressing dysplasia. Our results also indicate that CNV at multiple loci-in contrast to single locus occurrences-is characteristic of progressing dysplasia. Conclusions: This study suggests that genetic abnormalities of the true precancer demonstrate the progression risk which cannot be delineated by current histopathologic diagnosis.

COMPARATIVE ANALYSIS OF STATION BLACKOUT ACCIDENT PROGRESSION IN TYPICAL PWR, BWR, AND PHWR

  • Park, Soo-Yong;Ahn, Kwang-Il
    • Nuclear Engineering and Technology
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    • v.44 no.3
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    • pp.311-322
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    • 2012
  • Since the crisis at the Fukushima plants, severe accident progression during a station blackout accident in nuclear power plants is recognized as a very important area for accident management and emergency planning. The purpose of this study is to investigate the comparative characteristics of anticipated severe accident progression among the three typical types of nuclear reactors. A station blackout scenario, where all off-site power is lost and the diesel generators fail, is simulated as an initiating event of a severe accident sequence. In this study a comparative analysis was performed for typical pressurized water reactor (PWR), boiling water reactor (BWR), and pressurized heavy water reactor (PHWR). The study includes the summarization of design differences that would impact severe accident progressions, thermal hydraulic/severe accident phenomenological analysis during a station blackout initiated-severe accident; and an investigation of the core damage process, both within the reactor vessel before it fails and in the containment afterwards, and the resultant impact on the containment.

Simulation Study of the Bus Progression Signal System ("버스연동신호의 시뮬레이션 연구)

  • 설재훈;박창호
    • Journal of Korean Society of Transportation
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    • v.5 no.2
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    • pp.5-18
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    • 1987
  • Buses arrive at a traffic intersection later than passenger cars by the amount of dwell time at previous bus stops. This late arrival of buses affects the total passenger delay at intersections especially in the street carrying large bus volume. The bus progression signal system in which the signal offset is given in favor of bus platoons was applied in the case area of Kangnam street in Seoul, and various effects were analyzed using the TRANSYT-7F simulation model. It was observed that the total passenger delay can be reduced significantly if the bus progression signal system is applied, and the most effective bus priority treatment is proved to be the bus progression signal system installed with exclusive bus lanes.

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Cell Cycle and Cancer

  • Park, Moon-Taek;Lee, Su-Jae
    • BMB Reports
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    • v.36 no.1
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    • pp.60-65
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    • 2003
  • Cancer is frequently considered to be a disease of the cell cycle. As such, it is not surprising that the deregulation of the cell cycle is one of the most frequent alterations during tumor development. Cell cycle progression is a highly-ordered and tightly-regulated process that involves multiple checkpoints that assess extracellular growth signals, cell size, and DNA integrity. Cyclin-dependent kinases (CDKs) and their cyclin partners are positive regulators of accelerators that induce cell cycle progression; whereas, cyclin-dependent kinase inhibitors (CKIs) that act as brakes to stop cell cycle progression in response to regulatory signals are important negative regulators. Cancer originates from the abnormal expression of activation of positive regulators and functional suppression of negative regulators. Therefore, understanding the molecular mechanisms of the deregulation of cell cycle progression in cancer can provide important insights into how normal cells become tumorigenic, as well as how cancer treatment strategies can be designed.