• 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.

• Journal of the Korea Society for Simulation
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• v.17 no.1
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• pp.33-42
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• 2008

In general, simulation is to predict or evaluate some systems that are hard to be executed in real world, and so usually the target systems to be modeled are large and complex. Trying to observe the dynamics of the systems results in similar level of animation complexity, the model and animation has the same complexity as the system. Trying to display all the graphic objects representing the dynamics of the models being simulated, however, causes the distraction of focus, which results in solving the above listed problems difficult. The redundant graphic objects also increase the computer computation overhead. To solve the problem, a research about a hierarchical animation environment has been proposed a few years ago. In the research, the users can have better focus on the dynamics of system components by selectively choosing the hierarchical level and components within a level of the hierarchically structured model. However, the research has not a modeling methodology for modelers to describe systematically animation part corresponding to dynamics of simulation in a model. This research has defined the modeling methodology of DESHA and defined DESHA-C++, improving the previous research output, as an execution environment of DESHA models. In addition, to use hierarchical animation environment in various problems, this research proposed and developed the distributed simulation modeling environment that connects DESHA environment and HLA.

• Tuberculosis and Respiratory Diseases
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• v.49 no.2
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• pp.231-236
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• 2000

Benign metastasizing leiomyoma usually occurs in women and is associated with a past hysterectomy in 80% of the cases, which is a rare entity. The patient was a 39-year-old woman who complained of cough and sputum. She underwent hysterectomy because of benign leiomyoma ten years ago. Chest X-ray showed nodular lesion in the left lung field. Chest CT showed a 3cm sized round well defined mass at left hilum with mild indentation of segmental bronchi of left upper lobe and a small tiny nodule in right lower lung field. Nodular lesion of left upper 1000 was resected by thoracotomy. Pathological evaluation showed benign spindle-like cells having nuclei without cytotic atypia similar to those of benign leiomyoma. Immunohistochernical stainings for desmin and smooth muscle actin were positive. Therefore these nodules are considered as benign metastasizing leiomyoma from a uterine leiomyoma. We report this case with the review of literature.

• Tuberculosis and Respiratory Diseases
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• v.45 no.6
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• pp.1298-1304
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• 1998

The reports of sarcoidosis have increased in Korea since 1968. Osseous sarcoidosis is 3%-5% of sarcoidosis, but it is not reported upto date in Korea. So, we report a case of sarcoid dactylitis. A 47-year old woman who complained of painful swelling in her fingers was admitted in Korea University Guro Hospital. She had visited local clinics 3 years ago for chronic cough, multiple subcutaneous nodules and erythematous elevated regions on extensor sides of both extremities, and taken medicine under the diagnosis of pulmonary tuberculosis for 3 years. On admission her distal phalanges showed fusiform swelling, and multiple 1 cm-sized papules were found on the extensor area of extremities. The chest CT scan and the skin biopsy which had been performed in local clinics were reviewed to examine whether it was tuberculosis or not, but the results were compatible to sarcoidosis. So, under the impression of sarcoidosis chest CT and biopsy of hand lesions were performed again. And the patient was prescribed prednisolone 30 mg, and Hydroxychloroquine 400 mg per day, and then showed improvement of pain and skin lesions.

• Tuberculosis and Respiratory Diseases
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• v.48 no.6
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• pp.973-979
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• 2000

A glycogen storage disease(GSD) type I is a metabolic disease caused by a deficiency in one of the components of the glucose-6-phosphatase(G-6-Pase) system. This disorder results in hypoglycemia, hepatomegaly, lactic acidemia, hyperlipidemia, and hyperuricemia. Comon long(-)term complications include growth retaradation, gout, hepatic adenomas, osteoporosis and renal disease. However the cardiovascular system is rarely involved, and only six cases of pulmonary hypertension associated with GSD I have been reported in the literature. We experienced a case of pulmonary hypertension with type I GSD. A 31-year-old rnan, who had discovered type I GSD and received portocaval shunt operation 22 years ago, was admitted to the hospital with the chief complaint of dyspnea. Echocardiographic examination and cardiac catheterization revealed severe pulmonary hypertension. Nitric oxide and oral prostacycline derivative(beraprost) were tried without acute favorable response. After one year with beraprost, dyspnea, exercise capacity and hemodynamic parameters were improved. We report this case with a review of the literature.

• Journal of the Korea Concrete Institute
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• v.17 no.2 s.86
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• pp.237-245
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• 2005

In this paper, the changes of the period of cold weather concrete in Korea with the elapse of age are discussed to investigate the influence of elapse of age on period of cold weather concrete. The climate data of Korean Meteorological Administration(KMA) ranging from 1971 to 2000 was used. The period of cold weather concrete was calculated by following the specification of Korea Concrete Institute(KCI), American Concrete Institute(ACI) and Architectural Institute of Japan(AIJ), respectively. Previous research by the authors used the climate dada of KMA from 1961 to 1990 and research conducted by Kim M.H. used the climate data from 1931 to 1980 were also compared with the period of present paper. According to the results, in present paper, the period of cold weather concreting by KCI was calculated about 95days on average and the period by ACI was 101 days on average and the period by AIJI was 92days on average. For the variation of the period with the elapse of time, the period of cold weather concrete by KCI and ACI in present paper was shortened by as much as 5${\~}$6days compared with that of previous paper 10years ago. However, the period of cold weather concreting by AIJ did not exhibit a marked reduction in the period compared with that of previous paper by the author. But the period by Kim following AIJ exhibited a decrease in the period compared to the period by present paper by as much as 3days. For regional influence, the period of cold weather concreting in southern part of Korea was found to be much shorter than those at northern part. This may be due to the rising of mean temperature caused by global warming effect.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.214-214
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• 2003

During a model test of Hutton TLP, a "ringing" response was first observed about 20 years ago. This phenomenon is a resonant build up over the time of wave period and this burst-like motion can cause the extreme load on the TLP tether. It is often detected in the large and steep irregular waves but the generation mechanism leading to the "ringing" is not yet well understood. According to the research since then, the higher order harmonic components may account for the "ringing" on the floating offshore structures. The main purpose of the present research is, thus, to measure the higher harmonic forces exerted on a vertical truncated circular column and to compare them with available data. A vertical truncated cylinder with a diameter of 3.5inch and a draft of 10.5inch is used as a test structure, which is a scaled model of ISSC TLP column. The cylinder is installed at a distance of 45ft from the wave maker in order to avoid parasitic waves created in the wave flap. Attached to the upper part of the cylinder are two force gages to measure the horizontal (surge) and vertical (heave) forces on the cylinder. The incoming waves are Stokes waves with a slope ranging from 0.06 to 0.24. The forces and waves are measured for 60 seconds with a sampling rate of 50 Hz. Among the recorded data, the first 10 waves are excluded because of transient behavior of the waves and the next The horizontal and vertical forces are analyzed up to 5th order harmonics. The horizontal forces are then compared to the values from the theoretical model called "FNV model". In addition, force transfer functions are also investigated. Major findings in this research are below. 1) The first order forces measured are slightly larger than the theoretical values of "FNV model" 2) The "FNV model" considerably overpredicts the second order forces. 3) The larger the amplitude and more extreme the wave slope, the smaller the predictions are compared to the experimental. 4) The higher harmonic forces are significantly smaller than the first harmonic force for all wave parameters. 5) The normalized forces vs. waves slopes are almost constant in the lower harmonics but vary a lot in the higher harmonics. 6) The trend of forces is more nonlinear in the horizontal forces than in the vertical forces as the wave slope increases. 7) The part of the results above is also observed by other researchers and confirmed again through the present work.

• Journal of Korea Water Resources Association
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• v.52 no.10
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• pp.753-761
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• 2019

Localized heavy storm is one of the major causes of flood damage in urban regions. According to the recent disaster statistics in South Korea, the frequency of urban flood is increasing more frequently, and the scale is also increasing. However, localized heavy storm is difficult to predict, making it difficult for local government officials to deal with floods. This study aims to construct a Flood risk matrix (FRM) using ensemble weather prediction data and to assess its applicability as a means of reducing damage by securing time for such urban flood response. The FRM is a two-dimensional matrix of potential impacts (X-axis) representing flood risk and likelihood (Y-axis) representing the occurrence probability of dangerous weather events. To this end, a regional FRM was constructed using historical flood damage records and probability precipitation data for basic municipality in Busan and Daegu. Applicability of the regional FRMs was assessed by applying the LENS data of the Korea Meteorological Administration on past heavy rain events. As a result, it was analyzed that the flood risk could be predicted up to 3 days ago, and it would be helpful to reduce the damage by securing the flood response time in practice.

• Journal of architectural history
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• v.28 no.2
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• pp.77-90
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• 2019

The Sacheonwangsa temple in Silla was completed in 679, just after the unification of the Three Kingdoms. In recent years, we have been critically considering the history of the chronology based on the existence of 'Geumdang of the previous generation', which has emerged through the research report of the Sacheonwangsa temple. It is the one to reconsider the construction process of the Sacheonwangsa temple centering on the re-interpretation of the construction time and the character of the first stage of the foundation which was confirmed from within the Geumdang site. The results of this study are as follows : 1)The "Chang(創) of Sacheonwangsa temple" in [Three Affairs that Queen Seondeok had already known] that it is presumed that the construction of the Sacheonwangsa temple, which was designed by Anham before 640 years ago, will convey the fact that the first of the King Munmu's reign (661 ~) has been finalized after the initial discussion. 2)Although the theories after excavations are predicated on the existence of 'Geumdang of the previous generation', there is no reason to believe that a lasting predecessor building with roof and pillar walls on predecessor buildings is considered to have been built. The foundation was associated with the "build a temple out of coloured silk(以彩帛營寺)" i.e. 'Jochang(祖創)' in 670 years before the construction plan was formally finalized. However, it is presumed that the remains of the platform construction on the premise that it will be used on the construction of Geumdang. 3)The decision to 'rebuilding( ??)' based on a formal construction plan is determined to be from 670 to 672 years. The maintaining of the original cathedral axis line, to the north on the boundary of the southern limit of the foundation flat portion, the result of developing and embodied the relative position of the Geumdang in the newly determined cathedral unfold and embody, the center of the building base and Geumdang, it is presumed that the centers of them are divided into North and south. 4)The completion of the Sacheonwangsa temple in 679 is understood as the conclusion of 'rebuilding' to "build a temple out of coloured silk" i.e. 'Jochang' in 670 years. The pent roof of the Geumdang was initially considered not to be in the plan, but it is judged to be before the completion of the Sacheonwangsa temple.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.1
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• pp.33-46
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• 2019

Even though Korea is strengthening the support for startups due to the limitations of growth policies focusing on large companies, the survival rate of startups is very low, so that there should be more efforts to increase the survival rate of startups. As the existing startup support institutions have provided only fragmentary supports to startups, it would be necessary to have the comprehensive support institutions. As an alternative, the accelerator providing the comprehensive support such as spatial support, education, mentoring, networking, seed investment, and connection for follow-up investment to the initial startups was legalized in Korea of 2016, based on the registration system. Currently, within less than two year from then, there have been much interest in it enough to have about 136 registered accelerators. In the United States, the accelerator was introduced more than ten years ago. In Korea, however, it is still in the initial stage, so that the researches or social consensus on the accelerator are not sufficient. Thus, this study aims to suggest the measures for the development of accelerator and the consensus on the decision making for the selection of accelerator of startups, by researching which parts are considered when startups in the accelerator stage select the accelerator. As a result of the empirical analysis, the factor that has the greatest influence on decision making factors when startup chooses an accelerator was the subsequent investment attraction. This can be explained to the accelerator as desired, considering the factor that the startup of the initial stage places the most importance on growth as investment. We hope that these research results will be sustainable in future research related to accelerators, in hopes that it will be useful for establishing accelerator policies for domestic startups and direction for revitalizing related industries.