• Journal of Internet Computing and Services
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• v.10 no.5
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• pp.65-78
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• 2009

The most commonly adopted approach to find valuable information from tree data is to extract frequently occurring subtree patterns from them. Because mining frequent tree patterns has a wide range of applications such as xml mining, web usage mining, bioinformatics, and network multicast routing, many algorithms have been recently proposed to find the patterns. However, existing tree mining algorithms suffer from several serious pitfalls in finding frequent tree patterns from massive tree datasets. Some of the major problems are due to (1) modeling data as hierarchical tree structure, (2) the computationally high cost of the candidate maintenance, (3) the repetitious input dataset scans, and (4) the high memory dependency. These problems stem from that most of these algorithms are based on the well-known apriori algorithm and have used anti-monotone property for candidate generation and frequency counting in their algorithms. To solve the problems, we base a pattern-growth approach rather than the apriori approach, and choose to extract maximal frequent subtree patterns instead of frequent subtree patterns. The proposed method not only gets rid of the process for infrequent subtrees pruning, but also totally eliminates the problem of generating candidate subtrees. Hence, it significantly improves the whole mining process.

• Journal of KIISE:Software and Applications
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• v.32 no.12
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• pp.1217-1228
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• 2005

Recently, since DNA computing has been widely studied for various applications, DNA sequence design which is the most basic and important step for DNA computing has been highlighted. In previous works, DNA sequence design has been formulated as a multi-objective optimization task, and solved by elitist non-dominated sorting genetic algorithm (NSGA-II). However, NSGA-II needed lots of computational time. Therefore, we use an $\varepsilon$- multiobjective evolutionarv algorithm ($\varepsilon$-MOEA) to overcome the drawbacks of NSGA-II in this paper. To compare the performance of two algorithms in detail, we apply both algorithms to the DTLZ2 benchmark function. $\varepsilon$-MOEA outperformed NSGA-II in both convergence and diversity, $70\%$ and $73\%$ respectively. Especially, $\varepsilon$-MOEA finds optimal solutions using small computational time. Based on these results, we redesign the DNA sequences generated by the previous DNA sequence design tools and the DNA sequences for the 7-travelling salesman problem (TSP). The experimental results show that $\varepsilon$-MOEA outperforms the most cases. Especially, for 7-TSP, $\varepsilon$-MOEA achieves the comparative results two tines faster while finding $22\%$ improved diversity and $92\%$ improved convergence in final solutions using the same time.

• Journal of Educational Research in Mathematics
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• v.9 no.1
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• pp.81-109
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• 1999

This study aims to reflect the basic principles and teaching-teaming principles of Realistic Mathematics Education in order to suppose an way in which mathematics as an activity is carried out in primary school. The development of what is known as RME started almost thirty years ago. It is founded by Freudenthal and his colleagues at the former IOWO. Freudenthal stressed the idea of matheamatics as a human activity. According to him, the key principles of RME are as follows: guided reinvention and progressive mathematisation, level theory, and didactical phenomenology. This means that children have guided opportunities to reinvent mathematics by doing it and so the focal point should not be on mathematics as a closed system but on the process of mathematisation. There are different levels in learning process. One should let children make the transition from one level to the next level in the progress of mathematisation in realistic contexts. Here, contexts means that domain of reality, which in some particular learning process is disclosed to the learner in order to be mathematised. And the word of 'realistic' is related not just with the real world, but is related to the emphasis that RME puts on offering the students problem situations which they can imagine. Under the background of these principles, RME supposes the following five instruction principles: phenomenological exploration, bridging by vertical instruments, pupils' own constructions and productions, interactivity, and interwining of learning strands. In order to reflect how to realize these principles in practice, the teaming process of algorithms is illustrated. In this process, children follow a learning route that takes its inspiration from the history of mathematics or from their own informal knowledge and strategies. Considering long division, the first levee is associated with real-life activities such as sharing sweets among children. Here, children use their own strategies to solve context problems. The second level is entered when the same sweet problems is presented and a model of the situation is created. Then it is focused on finding shortcomings. Finally, the schema of division becomes a subject of investigation. Comparing realistic mathematics education with constructivistic mathematics education, there interaction, reflective thinking, conflict situation are many similarities but there are alsodifferences. They share the characteristics such as mathematics as a human activity, active learner, etc. But in RME, it is focused on the delicate balance between the spontaneity of children and the authority of teachers, and the development of long-term loaming process which is structured but flexible. In this respect two forms of mathematics education are different. Here, we learn how to develop mathematics curriculum that respects the theory of children on reality and at the same time the theory of mathematics experts. In order to connect the informal mathematics of children and formal mathematics, we need more teachers as researchers and more researchers as observers who try to find the mathematical informal notions of children and anticipate routes of children's learning through thought-experiment continuously.

• Korean Journal of Health Education and Promotion
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• v.19 no.4
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• pp.77-97
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• 2002

Since growth promotion was defined by Koch(1935), many researches like Benholdt and Thomsen(1942) have conducted studies for understanding problem of puberty growth. Growth promotion means that growth is developed in puberty, and several researchers have reported that the more becomes economic growth, the more becomes growth promotion. Thereupon, this study was attempted to find Maximum Growth Age(M.G.A.), as an index of height growth promotion in Korea, which was obtained by longitudinal observations of the same group. Thus, this study can explain the earlier tendency of growth. To investigate domestic changes in M.G.A., M.G.A. was calculated with the results of cross-sectional researchs using 25 representative papers between 1940-1953 including measurements by Lee(1940) and data by Kim(1953) in this study. Based on the research data published between 1940 and 2000, height and M.G.A. of males and females who were born between 1925 and 1983 were gotten by years, and a trend of growth promotion for height in Koreans was suggested by examining study subjects. Findings of this study are as follows; 1. M.G.A. for height decreased both in males and females; for males, 14.28 years in 1940, 14.24 in 1953, 13.86 in 1967, 12.74 in 1985, and 11.71 in 2000; for females, 12.0 in 1940, 11.52 in 1965, 10.00 in 1978 and 9.77 in 2000. 2. Regression equations and standard errors of estimate concerning M.G.A. for height by years were obtained; for males, Y$_1$(M.G.A.) = 17.21 - 0.059X$_1$, S$_{Y1X1}$(standard error of estimate about the regression line) = ${\pm}$0.62; for females, Y$_2$(M.G.A.) = 13.81-0.042X$_2$, S$_{Y2X2}$(standard error of estimate about the regression line) = ${\pm}$0.64 3. As a result of finding correlation between year and M.G.A. r=-0.763 (p<0.001) for male and r=-0.699(p<0.001) for female were obtained 4. From a view that the growth promotion has been continued before 2000, M.G.A. decreased 0.6 years for male and 0.4 for female per 10 years. 5. M.G.A. for height is as shown in Table 2. 6. It is thought that the future trend of growth promotion for height will follow the progress from 1940s to now. It shall be reviewed again after development of coming several years is investigated.

• Korea Journal of Hospital Management
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• v.18 no.4
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• pp.78-96
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• 2013

The purpose of this study is to analyze the emergency health care utilization using status according to income class. The target was the 2011 data out Korea Health Panel's raw data. 2011 data composed of total 17,035 people from total 5,741 households. This study set total 1,101 adults over full-20-years old having used an emergency health care utilization as its analysis target. In order to find out the number of emergency health care utilization use according to income class and the influential factors on emergency health care utilization cost, this study conducted the multiple regression analysis. And in order to more accurately analyze the emergency health care utilization use status depending on the income class and the features of emergency health care utilization use status, this study developed Models. As the result, this study found following findings. First, as the income class was lower, the gender was male, the age was lower, and the user has spouse, the user was not a business owner or a paid worker, the user is a house owner, the emergency medical facility type was a clinic, the means of transportation was others rather than 119 ambulance, the reason visiting emergency medical facility was belonged to others rather than accidents or poisoning, then the number of emergency was increased. Second, as the user was in higher income class, received the health insurance benefits, the using medical facility was general hospital, used 119 ambulance more often, stay days in emergency was shorter, then health care utilization cost was increased. In this study investigating the data out of Korea Health Panel, it was found that while the number of emergency health care utilization use was increased in the lower income class, but the emergency health care utilization cost was increased for higher income class. It is considered that this finding was caused from the facts that lower income class was more often exposed to dangers for physical health, so the number of emergency health care utilization use was increased, but their health care utilization cost was decreased because of their economic burdens against various examinations and their difficulties to pay such costs, comparing to that of higher income class. Therefore, in order to solve unequal problem of emergency health care utilization use between lower and higher income classs, it is required to set suitable solutions like the disease prevention effort by facilitating national health check-up programs, the enhancement of public health services in quantity and quality, the emergency health care utilization securing policy at using medical facilities, the promotional, educational activities about emergency health care utilization delivery system, the enhanced accessibility of emergency health care utilizations and emergency medical facilities.

• Publications of The Korean Astronomical Society
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• v.27 no.5
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• pp.419-429
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• 2012

In this paper, we propose a new re-quantization method after FFT processing to prevent the distortion of correlation result of VCS (VLBI Correlation Subsystem). The re-quantization is used to rearrange the data bit so as to reduce the data rate processed as 16-bit of FFT result of VCS. Having done this procedure, we found that the distorted spectrum of correlation result occurred in the delay tracking experiments by the re-quantization method introduced for initial design of VCS. In order to solve this, two kinds of re-quantization method, that is, the comparison and selection-type, are proposed. The first is to re-quantize the FFT result as a valid-bit by comparing with the input data after determining the adequate threshold. The second is manually to select the valid-bit of FFT result after finding the valid-field of data according to the bit-distribution of input data. We confirmed that the second is more effective compared with the first through the experimental result, and it will be implemented without so much modification of applied method in the condition of the limited resource of FPGA. The re-quantization is, however, carried out with 4-bit in the proposed second method for FFT result, and then the distortion of correlation result is also appeared. To fix this problem, the bit for re-quantization is extended to 8-bit. The proposed 8-bit selection-type is effectively verified so that the distortion of correlation result disappeared by applying to VCS in consequence of the simulation and correlation experiments.

• Journal of The Korean Association For Science Education
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• v.38 no.5
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• pp.649-665
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• 2018

In this study, we extracted the core competencies of makers through the analysis of critical incident technique and behavioral event interview to explore the nature and attributes of maker education, and then we developed a maker competency model based on these core competencies. As a result, six competency groups and 23 sub-competencies were extracted. In other words, we were able to confirm the existence of integrated thinking competency group consisting of four competencies made up of 'analytic thinking', 'intuitive thinking', 'visual thinking', and 'empirical thinking' and that of collaborative competency group with four competencies of 'sharing', 'communication', 'conflict management', and 'scrupulosity'. In addition, we could also confirm the existence of making mind competency group, which is composed of four competencies namely 'interest in various areas', 'challenge consciousness', 'failure management', and 'pleasure of the making process'. We could also confirm that human-centered competence group consisting of two competencies of 'humanity' and 'user-oriented' and the problem-finding competence group consisting of two competencies of 'observation' and 'recognition of discomfort in daily life'. Lastly, the making practice competency group is composed of seven competencies: 'understanding making tool', 'understanding electricity', 'understanding programming', 'planning', 'hand knowledge', 'information search', and 'direct execution'. We discussed educational implications of these findings.

• The Mathematical Education
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• v.43 no.4
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• pp.419-440
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• 2004

The purpose of this paper is to know the effects on number and operation abilities of the 1st grade children of elementary school by applying teaching and learning activity throught communication. For this purpose, we have studied according to the following procedure. 1. We divised teaching and learning model through communication and applied in the actual teaching and learning activity. 2. We investigated the effects of number and operations abilities of the 1st grade children by applying teaching and learning activity through communication. To accomplish this purpose, we applied learning activity through communication to the 1st grade of 40 elementary school children for about six months(September 1, 1999 ～ February 20, 2000). In process of applying this model, we collected all sorts of cases in the children's learning activity and investigated children's response on learning activity through communication, interview with children and researcher's observation. We applied the model through communication in class and compared with the traditional learning. 1. In learning through communication, children could solve the problem in themselves with a sense of responsibility. 2. It was impossible to find out the degree of children's comprehension in the explanatory learning. But in the learning through communication, it was a great help to individualize and plan the learning because children express their ideas clearly. It has conclusion as follows. The learning activity through communication has effected on forming number and operations abilities of the 1st grade of elementary school children importantly. 1. Children have improved in the abilities through communication to express their own ideas. 2. Children have studied with a sense of responsibility not in the teacher-oriented learning but in the self-directed learning 3. Children could find out the mathematical concepts in themselves - correcting false concepts, reguiding concepts by errors, finding invisible errors, solving problems variously and knowing the easy method. 4. The activity through communication in mathematics was a base of children's individual learning and important data of next learning plan. 5. The mathematical concepts formed through communication had a high transfer of learning. 6. Children have taken pleasure of discovery and had affirmative attitude about mathematics learning. We can make sure that number and operations abilities of the 1st grade children are formed by applying teaching and learning activity through communication. However, help and control of teacher have to be with it.

• Korean journal of food and cookery science
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• v.6 no.3 s.12
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• pp.85-94
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• 1990

The subject of this study was to yield data of dietetic education which could help the male teachers to live a desirable dietary life by analying the degree of balance of the diet, the interests in health and the subjective symptoms in disease, and finding the problem in the present dietary habit and the health state. Rusults were as follows: 1. The most regular meal in a day lunch and the most irregular was dinner. The sixties had meals most regularly. 2. The amount of smoking had influence on respiratory system and hepatobiliary system while daily amount of coffee intake influenced cardiobascalar system, diabetes mellitus and joint system. The amounts and the frequencies of alchol intake had no differences. 3. The factors which had meaningful relations with dietary habit were as follows; Salted food and so on had influences on cardiobascular system, spicy food on general disease, lipid intake including fried food, jun, bokchum on joint system, instant food and so forth on respiratory system. Fruit and so forth had influences on diabetes, salted food on hepatobilitary system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.5
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• pp.385-393
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• 2013

In the past decade, a paradigm shift from machine-centered to human-centered and from technology-driven to user-driven has been witnessed. Consequently, Social search is getting more social and Social Network Service (SNS) is a popular Web service to connect and/or find friends, and the tendency of users interests often affects his/her who have similar interests. If we can track users' preferences in certain boundaries in terms of Web search and/or knowledge sharing, we can find more relevant information for users. In this paper, we propose a novel Topic Sensitive_Social Relationship Rank (TS_SRR) algorithm. We propose enhanced Web searching idea by finding similar and credible users in a Social Network incorporating social information in Web search. The Social Relation Rank between users are Social Relation Value, that is, for a different topics, a different subset of the above attributes is used to measure the Social Relation Rank. We observe that a user has a certain common interest with his/her credible friends in a Social Network, then focus on the problem of identifying users who have similar interests and high credibility, and sharing their search experiences. Thus, the proposed algorithm can make social search improve one step forward.