• Journal of The Korean Association For Science Education
• /
• v.17 no.1
• /
• pp.21-29
• /
• 1997

Many middle school students have difficulty in understanding biological concepts because too many concepts are presented in the textbook compared to limited school hours. So, it is necessary to select concepts which are indispensable. The purpose of this study is to select key concepts in the unit 'The Continuity of Life' by surveying students' and teachers' cognition on the concepts. In this study, 78 concepts were extracted from 'Science 3', unit II 'The Continuity of Life'. To survey how students and teachers think the concepts, Likert type questionnaires were made. 300 third grade middle school students and 34 biology teachers were selected by random sampling and the questionnaires were applied. The following results were obtained:1. Students thought 59 concepts out of 78 were important and the mean score of important level of the concepts was 3.60. Students thought 26 concepts out of 78 were difficult and the mean score of diffculty level'of the concepts was 3.26. The more they think the concepts important, the more they think them difficult (r=0.7462, p<0.001). 2. Teachers thought 55 concepts out of 78 were important and the mean score of important level of the concepts was 3.82. Teachers thought 33 concepts out of 78 were difficult and the mean score of diffculty level of the concepts was 3.31. The more they think the concepts important, the more they think them difficult (r=0.6138, p<0.001). 3. The selected concepts were considered more important by teachers than by students(t=2.0150, p<0.05). However, there was no significant difference in evaluating the difficulty level of the concepts(t=0.7327, p>0.05). 4. It was found that students have difficulty in understanding concepts when they are presented in the textbook to require formal preparation than concrete preperation(t=2.6612, p<0.05).

• Journal of the Korean Chemical Society
• /
• v.58 no.1
• /
• pp.126-129
• /
• 2014

Concerning the difficulty of learning science and reduced interest in science, the authors of this study searched for potential threshold concepts which are portals or gateways in the field of science (particularly chemistry). The nature of these concepts and how to overcome their troublesomeness were further questioned. For this study, 239 high school students completed chemistry II provided information about what difficult concepts and potential threshold concepts in high school chemistry are and how they affect learning chemistry. In particular, the mastery experience of the threshold concepts was explored in detail. Two, "mole and atomic structure" were selected as threshold concepts in chemistry. Not only as important but also as threshold, this study emphasized the importance of the two concepts in terms of features characterizing them as threshold concepts. In particular, the features objectify subjective experiences of students and provide information describing the scientific meaning and distinctive nature of threshold concepts in science. Along with the data from teachers, this study shows the integrative feature as key criteria for students to make meaningful understanding of the two threshold concepts.

• School Mathematics
• /
• v.17 no.4
• /
• pp.571-591
• /
• 2015

Even though fractions make up one of the most important concepts in the domain of numbers in elementary math, it is difficult to teach or learn them due to their different quantity concepts and notation methods from natural numbers and their various concepts. The didactic transposition of fractions is thus important, and there is a need to examine the didactic concepts of fractions used in the South Korean textbooks for its research. This study compared elementary math textbooks among South Korea, Taiwan, and China and investigated differences in the instructional time and order of fraction concepts in the textbooks according to their didactic concepts and also differences in the instructional methods according to quantitative concepts.

• Journal of The Korean Association For Science Education
• /
• v.6 no.2
• /
• pp.35-42
• /
• 1986

Recent studies on the learning of the science concepts indicate that most students have misconceptions of the science concepts. The misconceptions have their roots in the various aspects of teaching and learning situations. The textbooks used in schools have been substantiated as one of the sources of the misconceptions. Genetics has been recognized as one of the most difficult areas for high school students to learn. Therefore, this study had its objective to identify the misconceptions of genetics held by high school students and analyze the high school biology textbook as the source of the misconceptions. In order to indentify the misconceptions of the genetic concepts, the volunteer students were interviewed and genetic content and its sequence in the high school biology textbooks were analyzed. The misconceptions identified in this study are as follow: gamete formation, mitosis, trait expression, and allele and gene behavior in meiosis. This study found that the high school biology textbooks might be the source of those misconceptions. Based on the misconceptions identified, this study proposed direction for efficient instruction of genetics in high schools.

• Journal of Radiation Protection and Research
• /
• v.20 no.3
• /
• pp.201-213
• /
• 1995

Protection against non-ionizing radiation(NIR) is the subject of an increasing interest but the use of very different concepts depending on the type of radiation or application, makes it rather difficult to compile studies and the data obtained in an uniformity in this field. The main object of the present paper is to summarizes and provide an inventory of concepts, quantities, units and terminology currently used for purposes of NIR protection. Furthermore a systematic classification and comparison of these quantities is given, and in particular the concepts used to quantify exposure limitation and radiation protection standards are summarized and discussed.

• Research in Mathematical Education
• /
• v.13 no.2
• /
• pp.75-90
• /
• 2009

There are concepts in calculus which are difficult to teach and learn. One of these concepts is integration. However, problem posing has not yet received the attention it deserves from the mathematics education community. There is no systematic study that deals with teaching of calculus concepts by problem posing oriented teaching strategy. In this respect this study investigated the effect of problem posing on students' (prospective teachers') academic success when problem posing oriented approach is used to teach the integral concept in Calculus-II (Mathematics-II) course to first grade prospective teachers who are enrolled to the Primary Science Teaching Program of Education Faculty. The study used intervention-posttest experimental design. Quantitative research techniques were employed to gather, analyze and interpret the data. The sample comprised 79 elementary prospective science teachers. The results indicate that problem posing approach effects academic success in a positive way and at significant level.

• Journal of the Korean Geographical Society
• /
• v.37 no.4
• /
• pp.425-441
• /
• 2002

This study focused on the geographical concepts development and its zone of proximal development(ZPD) through the collaborative interaction. Among the conclusions are: 1) Students who have higher cognitive structure represented the Creator Seoul Metropolitan Area(GSMA) as a geographical concepts, not as a spontaneous concepts. The concepts is developed from concrete facts, subordinate element concept to basic element concept hierarchically. The most difficult concept that the learner should internalize was represented as the basic element concept. 2) Although ZPD of GSMA is individualized, it could be divided into 9 types. The ZPD was developed differently according to the qualitative differences how much more and how systematically represented the geographical concepts. The characteristics shown in this development procedure was that there was a quality change based on quantity extensive.

• Journal of Mechanical Science and Technology
• /
• v.19 no.5
• /
• pp.1072-1079
• /
• 2005

Conceptual design is the first step in the overall process of product design. Its intrinsic uncertainty, imprecision, and lack of information lead to the fact that current conceptual design activities in engineering have not been computerized and very few CAD systems are available to support conceptual design. In most of the current intelligent design systems, approach of principle synthesis, such as morphology matrix, bond graphic, or design catalogues, is usually adopted to deal with the concept generation, in which optional concepts are generally combined and enumerated through function analysis. However, as a large number of concepts are generated, it is difficult to evaluate and optimize these design candidates using regular algorithm. It is necessary to develop a new approach or a tool to solve the concept generation. Generally speaking, concept generation is a problem of concept synthesis. In substance, this process of developing design candidate is a combinatorial optimization process, viz., the process of concept generation can be regarded as a solution for a state-place composed of multi-concepts. In this paper, genetic algorithm is utilized as a feasible tool to solve the problem of combinatorial optimization in concept generation, in which the encoding method of morphology matrix based on function analysis is applied, and a sequence of optimal concepts are generated through the search and iterative process which is controlled by genetic operators, including selection, crossover, mutation, and reproduction in GA. Several crucial problems on GA are discussed in this paper, such as the calculation of fitness value and the criteria for heredity termination, which have a heavy effect on selection of better concepts. The feasibility and intellectualization of the proposed approach are demonstrated with an engineering case. In this work concept generation is implemented using GA, which can facilitate not only generating several better concepts, but also selecting the best concept. Thus optimal concepts can be conveniently developed and design efficiency can be greatly improved.

• Industrial Engineering and Management Systems
• /
• v.15 no.2
• /
• pp.181-195
• /
• 2016

In a product environment where various product-service systems (PSSs) are already being provided, the provision of a different type of PSS is difficult for second movers but necessary for their sustainability and differentiation. Despite the importance of providing distinguishing PSSs to market, prior PSS studies have not effectively considered the influence of existing PSSs in their methods. In response, we suggest an approach to generate new PSS concepts by employing general needs (GNs) and business system evolution patterns (BSEPs). Our approach 1) identifies customer GNs fulfilled by existing PSSs, 2) generates advanced PSS ideas from an evolutionary perspective by mapping the existing PSSs onto BSEPs, and 3) selects PSS ideas that can meet the unfulfilled or insufficiently considered GNs using a GN-PSS linking matrix, thereby generating new PSS concepts based on the selected ideas. The workings and practicability of this approach are illustrated using a PSS case study of furniture industry. This approach would provide PSS planners with an ability to generate the differentiated PSS concepts that handle the customer needs that have been untapped throughout a product's lifecycle. In addition, this approach as a module will have a synergetic effect when incorporated with other PSS methodologies.

• The Mathematical Education
• /
• v.46 no.3
• /
• pp.315-329
• /
• 2007

The concepts of ratio, rate, and proportion are used in everyday life and are also applied to many disciplines such as mathematics and science. Proportional reasoning is known as one of the pivotal ideas in school mathematics because it links elementary ideas to deeper concepts of mathematics and science. However, previous research has shown that it is difficult for students to recognize the proportionality in contextualized situations. The purpose of this study is to understand how the mathematical concept in the middle school mathematics curriculum is connected with ratio, rate, and proportion and to investigate the characteristics of proportional reasoning through analyzing the concept including ratio, rate, and proportion on the middle school mathematics curriculum. This study also examines mathematical concepts (direct proportion, slope, and similarity) presented in a middle school textbook by exploring diverse interpretations among ratio, rate, and proportion and by comparing findings from literature on proportional reasoning. Our textbook analysis indicated that mechanical formal were emphasized in problems connected with ratio, rate, and proportion. Also, there were limited contextualizations of problems and tasks in the textbook so that it might not be enough to develop students' proportional reasoning.