• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.1
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• pp.1-8
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• 2010

The Fourier series uses a vibrating wave that possesses an amplitude that is like the one of the sine curve. Therefore, the functions used in the Fourier series do not change due to the value of the frequency and that set a limit to express irregular signals with rapid oscillations or with discontinuities in localized regions. However, the wavelet series analysis(WSA) method supplements these limits of the Fourier series by a linear combination of a suitable number of wavelets. By using the wavelet that is focused on time, it is able to give changes to the range in the cycle. Also, this enables to express a signal more efficiently that has singular configuration and that is flowing. The main objective of this study is to propose a scheme called wavelet series analysis for the application of wavelet theory to one-dimensional problems represented by the second-order elliptic equation and to evaluate theperformance of proposed scheme comparing with the finite element analysis. After a through evaluation of different types of wavelets, the HAT wavelet system is chosen as a wavelet function as well as a scaling function. It can be stated that the WSA method is as efficient as the FEA method in the case of axial bars with distributed loads, but the WSA method is more accurate than the FEA method at the singular points and its computation time is less.

• Journal of Science and Technology Studies
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• v.1 no.2 s.2
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• pp.371-398
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• 2001

Sciences and technologies are the sources which have formed presently highly developed civilizations and cultures and have enhanced the quality of human lives. But we see the dark sides of them as well as the bright sides, and we have the consciousness of environmental crisis and destruction of lives caused by them. Thus were are criticisms against human-tropism or technology-tropism from nature-tropism or deep ecology. However, if people would continue to have the desire of enjoying the present quality of their lives, they should try to develop and improve pro-environmental technologies. In this vein, we have the necessity of making environmental decisions and solving environmental problems by information technologies. Since the second half of the last century, 'environment' is the key word because we have the consciousness of environment strongly. As we solve human problems by making decisions of actions, we must face with environmental decisions in order to solve our environmental problems. If we have the better understanding of the nature of information and the role of information technology, and the relation of information technology and decision-making, we are able to design environmental systems and implement their optimal interfaces of environmental components. For this purpose, we are obliged to combine several useful technologies including GIS, DSS, Knowledge-based system and artificial neural networks. Therefore the developments and cooperations of these fields in environmental decision making enables us to live in the better and comfortable surrounding in the near future.

• Journal of Periodontal and Implant Science
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• v.37 no.4
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• pp.733-742
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• 2007

Bone morphogenetic proteins have been shown to possess significant osteoinSductive potential, but in order to take advantage of this effect for tissue engineering, carrier systems are essential. Successful carrier systems must enable vascular and cellular invasion, allowing BMP to act as a differentiation factor. The carrier should be reproducible, non-immunogenic, moldable, and space-providing, to define the contours of the resulting bone. The purpose of this study was to review available literature, in comparing various carriers of BMP on rat calvarial defect model. The following conclusions were deduced. 1. Bone regeneration of ACS/BMP, ${\beta}-TCP/BMP$, FFSS/BMP, $FFSS/{\beta}-TCP/BMP$, MBCP/BMP group were significantly greater than the control groups. 2. Bone density in the ACS/BMP group was greater than that in ${\beta}-TCP$, FFSS, $FFSS/{\beta}-TCP$ carrier group. 3. Bone regeneration in FFSS/BMP group was less than in ACS/BMP, ${\beta}-TCP/BMP$, MBCP/BMP group. However, New bone area of $FFSS/{\beta}-TCP/BMP$ carrier group were more greater than that of FFSS/BMP group. ACS, ${\beta}-TCP$, FFSS, $FFSS/{\beta}-TCP$, MBCP were used for carrier of BMP. However, an ideal carrier which was reproducible, non-immunogenic, moldable, and space-providing did not exist. Therefore, further investigation are required in developing a new carrier system.

• Journal of The Korean Association For Science Education
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• v.21 no.2
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• pp.385-399
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• 2001

In this study, the contexts and values of the movement called 'Science and Citizenship' during the 1930-50s are discussed in relation to the historical development of school science education in Britain and to the current STS movement in school science. A special attention is given to the activities and ideas of a then eminent biologist, Lancelot Hogben(1895-1975) who published a textbook-like science book, called "Science for the Citizen"(1938). From the beginning of the 20th century, there was a growing realization that British education system needed to be changed in order to provide school science teaching to a wider audience with more emphasis on the relevance, industrial and humanistic aspects of science. This was echoed by a lecture series called 'Science and Citizenship' which was reported in the School Science Review, then the only nationwide professional journal for science educators and by a group of professional scientists who had socialist ideas toward society. Hogben was one of the key member of the group and delivered the second lecture of 'Science and Citizenship', titled "Biological Instruction and education for Citizenship". Hogben's main idea, illustrated in this lecture as well as in "Science for the Citizen", was that science education should be a way of teaching citizen for promoting democratic society and to achieve that science need to be taught in more integrated, utilitarian and humanistic manners, for example by showing the usefulness, relevance, historical and democratic aspects of science. In addition, a summary of his own life and activities, the social background and socialist scientists of the time, and comparisons between 'Science and Citizenship' movement and the General Science movement in the UK as well as the progressive science education in the USA, and the STS education movement in 1980s are discussed.

• Journal of The Korean Association For Science Education
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• v.37 no.4
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• pp.611-624
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• 2017

The purposes of this study are to explore Iceberg(IB) model as a systems thinking analysis tool for high school students, suggest a systems thinking analysis method using rubrics and verify its validity and reliability. For this study, the theoretical basis was examined through literature analysis about IB model and rubrics of evaluating the systems thinking. And 6 high school students participated in IB model activity and were interviewed about polar climate change. In addition, quantitative tests using systems thinking scale were also conducted to support the results of the IB model activity analysis. Data obtained from IB model activity was analyzed by using the rubrics of evaluating system thinking developed by Hung (2008). The analysis results were reviewed by two professors to confirm the validity and reliability. In order to confirm the validity, correlation analysis were performed between the rubrics and the quantitative test results. Finding are as follows: Six students used the IB model to express their systems thinking in detail and the results of the systems thinking analysis of students using rubrics showed a distribution of 17~35 points. Furthermore, the results of correlation analysis between rubrics and systems thinking scale was highly correlated (Pearson product-moment is .856) on significance level from .05. Using the IB model introduced in this study, students express their systems thinking effectively and the results of the systems thinking analysis using IB model is considered to analyze validity and reliability. Based on the results of this study, implication suggests how to study the systems thinking in science education.

• Journal of The Korean Association For Science Education
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• v.37 no.5
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• pp.813-824
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• 2017

In the previous studies on co-constructing scientific models, students have had various difficulties in constructing their models. As an alternative to compensate for these problems, we introduced smart devices in the modeling process and examined its roles. 60 students from two classes in the fifth grade of an elementary school in Seoul had classes to make up the solar system model in a small group using the smart devices and we examined the roles of smart devices in their classes. The result is as follows; First, students were able to generate their scientific model through various functions of smart devices throughout the modeling process. In particular, smart devices provide highly descriptive and authoritative information that meets the needs of students as well as the opportunity to observe the planets from various perspectives. Moreover, they were not only able to express their models easily as they wanted to express them, but also were able to receive feedbacks from various agents. In order for these smart devices to function properly in the co-construction of scientific models, it is necessary to improve the related environment as well as students' technological literacy.

• Journal of Korea Port Economic Association
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• v.27 no.4
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• pp.13-35
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• 2011

The advancement of the information technology provides a wide range of corporate to cope with new business environments that are different in size, life and operation conditions. The Research methodology used in this study is Technology Acceptance Model. The Study Method are mainly survey and questionnaire. The major result of article can be summarized. Its are as the follows: This paper ware investigated the determinants of 'port service quality', 'perceived usefulness', 'perceived ease of use', 'utilization intention', 'practice use'. There are 400 sended samples and 150 returns, 173 of them are analyzed on a port utilization using TAM model. 1. The Port service quality are found to have a positive effect to 'perceived usefulness', 'perceived ease of use', 'utilization intention' 2. The perceived ease of use are found to have a positive effect to 'perceived usefulness', 'utilization intention' 3. The perceived usefulness is found to be positively related to 'utilization intention' 4. The utilization intention is found to have a positive effect to ''practice use' we hove to provide useful contribution to increase the Korea ports' competitiveness in introduction of port information system. In addition, in order to port development offer some insight in further research.

• Journal of Adhesion and Interface
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• v.2 no.4
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• pp.1-9
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• 2001

Silicone sealants are composed of polymer, plasticizer, crosslinker, catalyst and filler. Types and compositions of components are effected on sealant performances. In recent, use of alkoxy type silicone sealant increased due to environmental advantage. In this study, we investigated effects of component types and ratios on one-part room temperature curable alkoxy type silicone sealant preparation and adhesion properties. Alkoxy type silicone sealants were prepared with various PDMS (polydimethylsiloxane) viscosities. In addition, the effect of plasticizer, crosslinkers, and catalyst on sealant obtained from by mixture of PDMS viscosities of 20000 and 80000 was investigated. Reaction temperature on change of mixing time was observed, and then proper crosslinking systems were found. Adhesion (properties) of silicone sealants were measured. In the sealants preparation, stable reaction was achieved by adjusting composition variance ratio in the sealant mixture temperature below $40^{\circ}C$. The adhesion properties of sealant differ from substrate composition. The order of adhesion strength was glass/glass > glass/aluminum > aluminum/aluminum system. The elongation of sealant was increased as polymer viscosity and plasticizer content increased. The strength was increased as crosslinker and plasticizer decreased, while catalyst increased.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.10 no.16
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• pp.101-106
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• 1987

Statistical control charts are useful tools to monitor and control the manufacturing processes and are widely used in most Korean industries. Many Korean companies, however, do not always obtain desired results from the traditional control charts by Shewhart such as the $\bar{X}$-chart, $\bar{X}$-chart, $\bar{X}$-chart, etc. This is partly because the quality charterstics of the process are not distributed normally but are skewed due to the intermittent production, small lot size, etc. In Shewhart $\bar{X}$-chart. which is the most widely used one in Kora, such skewed distributions make the plots to be inclined below or above the central line or outside the control limits although no assignable causes can be found. To overcome such shortcomings in nonnormally distributed processes, a distribution-free type of confidence interval can be used, which should be based on order statistics. This thesis is concerned with the design of control chart based on a sample median which is easy to use in practical situation and therefore properties for nonnormal distributions may be easily analyzed. Control limits and central lines are given for the more famous nonnormal distributions, such as Gamma, Beta, Lognormal, Weibull, Pareto, Truncated-normal distributions. Robustness of the proposed median control chart is compared with that of the $\bar{X}$-chart; the former tends to be superior to the latter as the probability distribution of the process becomes more skewed. The average run length to detect the assignable cause is also compared when the process has a Normal or a Gamma distribution for which the properties of X are easy to verify, the proposed chart is slightly worse than the $\bar{X}$-chart for the normally distributed product but much better for Gamma-distributed products. Average Run Lengths of the other distributions are also computed. To use the proposed control chart, the probability distribution of the process should be known or estimated. If it is not possible, the results of comparison of the robustness force us to use the proposed median control chart based oh a normal distribution. To estimate the distribution of the process, Sturge's formula is used to graph the histogram and the method of probability plotting, $\chi$$^2$-goodness of fit test and Kolmogorov-Smirnov test, are discussed with real case examples. A comparison of the proposed median chart and the $\bar{X}$ chart was also performed with these examples and the median chart turned out to be superior to the $\bar{X}$-chart.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.6
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• pp.794-802
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• 2018

The ice resistance series charts for icebreaking ships were developed through a series of systematic model tests in the ice tank of the Korean Research Institute of Ship and Ocean Engineering (KRISO). Spencer's (1992) component-based scaling system for ship-ice model tests was applied to extend the model ship correlations. Beam to draft ratio (B/T), length to beam ratio (L/B), block coefficient ($C_B$) and stem angle (${\alpha}$) were selected as geometric parameters for hull form development. The basic hull form (S1) of twin pod type with B/T of 3.0, L/B of 6.0, $C_B$ of 0.75 and stem angle of $25^{\circ}$ was generated with a modern hull design concept. A total of 13 hulls were designed varying the geometric parameters; B/T of 2.5 and 3.5, L/B of 5.0 and 7.0, $C_B$ from 0.65 to 0.85 in intervals of 0.05, and 5 stem angles from $15^{\circ}$ to $35^{\circ}$. Ice resistance tests were first carried out with the basic hull form in level ice with suitable speed. Four more tests for $C_B$ variations from 0.65 to 0.85 were conducted and two more for beam to draft and length to beam ratios were also performed to study the effect of the geometric parameters on ice resistance. Ice resistance tests were summarized using the volumetric coefficient, $C_V$ ($={\nabla}/L^3$), instead of L/B and $C_B$ variations. Additional model tests were also carried out to account for the effect of the stem angle, ice thickness and ice strength on ice resistance. In order to develop the ice resistance series charts with a minimum number of experiments, the trends of the ice resistance obtained from the experiments were assumed to be similar for other model ship with different geometric parameters. A total of 18 sheets composed of combinations of three different beam to draft ratios and six block coefficients were developed as a parameter of $C_V$ in the low speed regions. Three correction charts were also developed for stem angles, ice thickness and ice strength respectively. The charts were applied to estimate ice resistance for existing icebreaking ships including ARAON, and the results were satisfactory with reasonable accuracy.