• School Mathematics
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• v.11 no.1
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• pp.17-37
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• 2009

Concept and model of multiplication is not single. Concepts of multiplication can be classified into three cases: repeated addition, times idea, pairs set. Models of multiplication can be classified into four cases: measurement, rectangular pattern, combinatorial problem, number line. Among diverse cases of multiplication's concept and model, which case does elementary mathematics education lay stress on? This question is a controvertible didactical point. In this thesis, (1) mathematical and didactical analysis of multiplication's concept and model is performed, (2) a concrete program of teaching multiplication which is based on times idea is contrived, (3) With this new program, the teaching experiment is performed and its result is analyzed. Through this study, I obtained the following results and suggestions. First, the degree of testee's understanding of times idea is not high. Secondly, a sort of test problem which asks the testee to find times value is more easy than the one to find multiplicative resulting value. Thirdly, combinatorial problem can be handled as an application of multiplication. Fourthly, the degree of testee's understanding of repeated addition is high. In conclusion, I observe the fact that this new program which is based on times idea could be a alternative program of teaching multiplication which could complement the traditional method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.587-593
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• 2019

The field of geospatial information is rapidly changing due to the development of sensor and data processing technology that can acquire location information. And demand is increasing in various related industries and social activities. The construction and utilization of three dimensional geospatial information that is easy to understand and easy to understand can be an essential element to improve the quality and reliability of related services. In recent years, 3D laser scanners are widely used as 3D geospatial information construction technology. However, 3D laser scanners may cause shadow areas where data acquisition is not possible when objects are large in size or complex in shape. In this study, 3D model of an object has been created by acquiring oblique images using an unmanned aerial vehicle and processing the data. The study area was selected, oblique images were acquired using an unmanned aerial vehicle, and point cloud type 3D model with 0.02 m spacing was created through data processing. The accuracy of the 3D model was 0.19m and the average was 0.11m. In the future, if accuracy is evaluated according to shooting and data processing methods, and 3D model construction and accuracy evaluation and analysis according to camera types are performed, the accuracy of the 3D model will be improved. In the point cloud type 3D model, Cross section generation, drawing of objects, and so on, it is possible to improve work efficiency of spatial information service and related work.

• Journal of Intelligence and Information Systems
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• v.29 no.2
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• pp.285-301
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• 2023

Due to the increasing demand and importance of non-face-to-face education, open online learning platforms are getting interests both domestically and internationally. These platforms exhibit different characteristics from online courses by universities and other educational institutions. In particular, students engaged in these platforms can receive more learner autonomy, and the development of tools to assist learning is required. From the past, researchers have attempted to utilize process mining to understand realistic study behaviors and derive learning patterns. However, it has a deficiency to employ it to the open online learning platforms. Moreover, existing research has primarily focused on the process model perspective, including process model discovery, but lacks a method for the process pattern and instance perspectives. In this study, we propose a method to identify learning patterns within an open online learning platform using process mining techniques. To achieve this, we suggest three different viewpoints, e.g., model-level, variant-level, and instance-level, to comprehend the learning patterns, and various techniques are employed, such as process discovery, conformance checking, autoencoder-based clustering, and predictive approaches. To validate this method, we collected a learning log of machine learning-related courses on a domestic open education platform. The results unveiled a spaghetti-like process model that can be differentiated into a standard learning pattern and three abnormal patterns. Furthermore, as a result of deriving a pattern classification model, our model achieved a high accuracy of 0.86 when predicting the pattern of instances based on the initial 30% of the entire flow. This study contributes to systematically analyze learners' patterns using process mining.

• Journal of the Korean Chemical Society
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• v.63 no.6
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• pp.459-472
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• 2019

The purpose of this study was to investigate the effect of science writing for different audiences on preservice chemistry teachers' chemistry concept understanding and modeling ability in general chemistry experiment activities using Argument-based Modeling (AbM) strategy. And we also examined preservice chemistry teachers' perceptions of modeling in different audience groups. The participants of the study were 18 university students in the first grade of preservice chemistry teachers taking a general chemistry experiment course. They completed eleven topics of general chemistry experiment using argument-based modeling strategy. The understanding of chemistry concept was compared with the effect size of pre- and post-chemistry concept test scores. To find out modeling ability, we analyzed level of model by each preservice chemistry teacher. Analytical framework for the modeling ability was composed of three elements, explanation, representation, and communication. The questionnaire was conducted to check up on preservice chemistry teacher's recognition of modeling. The result of analyzing the effect of modeling for different audience on the understanding of chemistry concept and modeling ability, the preservice chemistry teachers' were found to be more effective when the level of audience was low. There was no difference in the recognition of modeling between the groups for audience. However, we could confirm that the responses of preservice chemistry teachers are changed in concrete when they have an experience in succession on modeling.

• Journal of Korean Academy of Nursing
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• v.16 no.1
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• pp.89-104
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• 1986

복잡한 사회문제해결에 유용한 접근방법의 하나인 계층분석과정은 수학자인 사티(Saaty)가 개발한 것으로서 이미 사회과학의 여러 분야에 적용되고 있다. 본 논문의 목적은 이 계층분석과정을 간호교육과 관련된 문제에 적용해 봄으로써 이 방법이 실제 문제해결을 위한 유용한 접근방법이 될 수 있는가를 고찰해 보는데 있다. .현대사회문제들은 다양한 관련요소, 그 요소들간이나 다른 문제들과의 복잡한 상호관계, 다수의 의사결정자의 참여, 무한한 대안, 문제의 결과에 대한 불확실성 등으로 인하여 단순한 모델이나 간단한 논리적 혹은 직관적인 판단에 준하여 일시에 해결하기 어려운 경우가 많다. 이러한 상황 하에서 문제와 관련된 요소들을 찾아내고 그 요소들을 계층적으로 분석하여 단계적으로 문제해결에 접근하는 계층분석과정을 활용함으로써 사회과학분야의 문제해결에 유용한 수단이 될 수 있다. 또한 문제와 관련된 요소를 규명하고 계층적으로 분화하는 과정에서 그 문제에 대한 보다 명확한 이해, 분석 및 현상의 흐름을 더 잘 인해하게 된다. 계층분석과정은 1) 계층구조의 설정 2) 구성요소들의 중요도 측정 3) 중요도에 따른 우선 순위의 산정 4) 우선 순위의 일관성 검토과정으로 요약된다. 본 논문에서는 이러한 과정을 통하여 미국 간호계에서 심각한 문제로 대두되어온 기본교육제도상의 쟁점(Issue of Entry into Practice）에 대한 문제 해결책이 마련되는지를 시도하였다. 즉, 기본교육 제도에 영향을 미칠 수 있는 요인들을 규명하여 계층화하고 계층내에 위치하는 구성요소들의 수평적 관계와 계층간의 수직적 관계를 체계적으로 검토하여 간호교육의 미래를 예측해 보았다. 간호교육제도에 영향을 미칠 수 있는 주요 요인들의 계층화는 거시적 환경차원(factors), 관련 이해자 집단차원(actors), 이해자 집단의 목표차원(objectives), 목표달성을 위한 정책차원(Policies), 그리고 간호교육제도의 미래를 예견한 시나리오(scenario)로 이루어졌다. 각 계층을 따라 단계적으로 중요도를 비교하여 최종적으로 각 시나리오의 우선순위 중요도(priority weight)를 구하였다. 각 시나리오의 우선순위 중요도를 간호교육과 관련된 4가지 차원들(학생, 교수, 교육기관, 직업)을 구성하고 있는 특성들에 가중하여 결과를 해석 하였다. 간호교육의 미래에 정치적(55%)과 경제적(25%) 요인이 가장 강한 영향을 미치고, 관련자중에서는 병원(38%) 의사(33%) 그리고 정부(23%)의 순으로 영향을 미친다고 분석되었다. 의외로 간호원 자신들은 큰 영향력이 없는 것으로 보여졌다. 4개의 시나리오 중에서는 그 우선순위 중요도가 현상유지(33%) 자발적4년제(32%), 강제 4년제(19%), 그리고 2~3년제의 우위(18%) 순으로 나타났다. 최종 시나리오 결과를 요약하면 1) 전체 학생수는 감소하나 양질의 간호학생수는 증가하며 2) 박사학위를 소지한 간호학 교수 및 전체 교수의 수가 증가할 것이다. 3) 전체 간호교육기여의 수는 약간 줄 것이며 그중 4년제 기관이 증가하고 반면에 2~3년제의 기관은 감소할 것이다. 4) 전문간호원이 되기 위한 입학용이도에는 별차이가 없겠으나 간호원들의 보수, 지위 및 자율성이 증가하면서 전반적인 간호의 질이 향상될 것이다. 계층분석과정의 적용으로 미국 간호교육계의 가까운 미래를 위와 같이 예견하여 보았으나 이 과정은 예견 뿐 만 아니라 일반적인 의사결정이나 문제 해결의 도구이외에도 복잡한 사회문제의 본질을 분석, 이해함으로써 보다 정화한 정책문제를 규정하는 데에도 유용할 것이다.

• Development and Reproduction
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• v.11 no.2
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• pp.59-66
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• 2007

Understanding molecular mechanisms that control embryonic stem cell (ESC) self-renewal and differentiation is important for the development of ESC-based therapies. Statins, inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase), potently reduce cholesterol level. As well as inhibiting cholesterol synthesis, statins inhibit other intermediates in the mevalonate pathway such as farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP), major substrates for protein isoprenylation. Studies showed that pleiotropic effects of statins beyond cholesterol lowering property arise from inhibition of protein isoprenylation that is involved in various cellular functions including proliferation and differentiation. It has been determined that statins have inhibitory effect on ESC self-renewal and stimulatory effect on ESC differentiation into adipogenic/osteogenic lineages. Importantly, statins mediate downregulation of ESC self-renewal by inhibiting RhoA-dependent signaling, independently of their choresterol-lowering properties. Understanding statin's actions on ESCs may provide important insights into the molecular mechanisms that regulate self-renewal or differentiation of ESCs.

• Journal of Educational Research in Mathematics
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• v.26 no.4
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• pp.635-662
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• 2016

Combinatorics, the basis of probabilistic thinking, is an important area of mathematics and closely linked with other subjects such as informatics and STEAM areas. But combinatorics is one of the most difficult units in school mathematics for leaning and teaching. This study, using the designed combinatorial models and executable expression, aims to analyzes the eye movement of graduate students when they translate the written combinatorial problems to the corresponding executable expression, and examines not only the understanding process of the written combinatorial sentences but also the degree of difficulties depending on the combinatorial semantic structures. The result of the study shows that there are two types of solving process the participants take when they solve the problems : one is to choose the right executable expression by comparing the sentence and the executable expression frequently. The other approach is to find the corresponding executable expression after they derive the suitable mental model by translating the combinatorial sentence. We found the cognitive processing patterns of the participants how they pay attention to words and numbers related to the essential informations hidden in the sentence. Also we found that the student's eyes rest upon the essential combinatorial sentences and executable expressions longer and they perform the complicated cognitive handling process such as comparing the written sentence with executable expressions when they try the problems whose meaning structure is rarely used in the school mathematics. The data of eye movement provide meaningful information for analyzing the cognitive process related to the solving process of the participants.

• Tunnel and Underground Space
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• v.20 no.4
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• pp.267-276
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• 2010

In modern rock engineering practice, fully grouted rock bolting is actively employed as a major supporting system, so that understanding the behavior of fully grouted rock bolts is essential for the precise design of rock bolting. Despite its importance, the supporting mechanism of rock bolts has not been fully understood yet. Since most of existing analytical models for rock bolts were developed by drastically simplifying their boundary conditions, they are not suitable for the bolts of in-situ condition. In this study, 3-D elastic FE analysis of fully grouted rock bolts has been conducted to provide insight into the supporting mechanism of the bolt. The distribution of shear and axial stresses along the bolt are investigated with the consideration of different boundary conditions including three different displacement boundary conditions at the bolt head, the presence of intersecting rock joints, and the variation of elastic modulus of adjacent rock. The numerical result reveals that installation of the faceplate at the bolt head plays an important role in mobilizing the supporting action and enhancing the supporting capabilities of the fully grouted rock bolts.

• Journal of The Korean Association For Science Education
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• v.18 no.2
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• pp.209-219
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• 1998

This study is the first part of the investigation of the students' and teachers' understanding of ideal conditions in physics. To do this, here, we provided the theoretical basis for the above study by discussing the meaning and characteristics of idealization. Idealization, introduced and elaborated by Galileo therefore characterized the nature of modem science, can be generated by four procedures: neglecting the minor variables, giving without any description about the minor variables, assuming the limit case, assuming constancy or uniformity. Idealization generated by these procedures can produce models and laws from the sensory informations about real world. And physics world is constructed by formalization or mathematization of these models and laws obtained through idealization about real world. Therefore, it can be said that idealization have a major role in the context of discovery. By this aspects, physics world can be viewed as the approximation of the real world, and this view, again, give rise the philosophical debate about the reality in nature. Idealization take an important role in the process of application of physics world and the understanding the real world. That is, physicists accept the discrepancies between real world, and physics world and make a great effort to explain, moreover, reduce these discrepancies by modifying or eliminating idealization involved in physics world. Continued from this study, we will proceed to obtain the implications of idealization on the physics learning and investigate the students' and teachers' understanding of the ideal condition involved in the theoretical explanation and the experiment in physics.

• Journal of The Korean Association For Science Education
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• v.36 no.5
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• pp.729-737
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• 2016

Natural selection is the core idea of evolution that pre-service biology teachers need to understand to solve diverse biological problem. This study aims to investigate the level of Korean pre-service biology teachers' understanding of natural selection by comparing their knowledge with their Chinese, American, and German biology major undergraduate counterparts. In particular, this study focuses on two conceptual components of natural selection (i.e., ecology and genetics). This study used a total 1226 pre-service biology teachers and biology majors' data. The instrument measuring the understanding of natural selection concepts was Conceptual Inventory of Natural Selection, which consists of ten ecology concept items and ten genetics concept items. The Rasch model analysis, multivariate analysis of variance, and univariate analysis of variance were used for the statistical tests. The result reveals that the level of Korean pre-service biology teachers' understanding of natural selection were similar with Chinese undergraduates' understanding and significantly lower than American and German undergraduates.' In the first year student data, the level of genetics concept of Korean pre-service biology teachers were significantly lower than Chinese and German students. In the fourth year student data, the level of ecology concept of Korean pre-service biology teachers were significantly lower than American and German students. Based on these results, the ecology concept education and balanced natural selection concept education are discussed.