• Journal of Practical Engineering Education
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• v.14 no.3
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• pp.505-512
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• 2022

The purpose of this study is to synthesize effects of the living lab-based education through meta-analysis. Seven primary studies reporting the effect of living lab-based education were carefully selected for data analysis. Research questions are as follows. First, what is the overall effect size of the living lab-based education? The overall effect size refers to the effect on the cognitive and affective domains. Second, what is the effect size of the living lab-based education according to categorical variables? Categorical variables are outcome characteristics, study characteristics, and design characteristics. Results are summarized as follows. First, the overall effect size of living lab-based education was 0.347. Second, the effect size according to the cognitive domain was 1.244 for information process, 0.593 for communication, 0.261 for problem solving, and 0.26 for creativity. Third, the effect size according to subject area was shown in the order of electrical and electronic engineering 1.146, technology and home economics 0.489, artificial intelligence 0.379, and practical arts 0.168. Fourth, the effect size according to school level was 1.058 for high school, 0.312 for middle school, and 0.217 for elementary school. Fifth, the effect size by grade level was 0.295 when two or more grades were integrated and 0.294 for a single grade.

• Journal of Energy Engineering
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• v.28 no.3
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• pp.65-79
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• 2019

The study attempted to estimate the optimal facility capacity by combining renewable energy sources that can be connected with gas CHP in industrial complexes. In particular, we reviewed industrial complexes subject to energy use plan from 2013 to 2016. Although the regional designation was excluded, Sejong industrial complex, which has a fuel usage of 38 thousand TOE annually and a high heat density of $92.6Gcal/km^2{\cdot}h$, was selected for research. And we analyzed the optimal operation model of CHP Hybrid System linking fuel cell and photovoltaic power generation using HOMER Pro, a renewable energy hybrid system economic analysis program. In addition, in order to improve the reliability of the research by analyzing not only the heat demand but also the heat demand patterns for the dominant sectors in the thermal energy, the main supply energy source of CHP, the economic benefits were added to compare the relative benefits. As a result, the total indirect heat demand of Sejong industrial complex under construction was 378,282 Gcal per year, of which paper industry accounted for 77.7%, which is 293,754 Gcal per year. For the entire industrial complex indirect heat demand, a single CHP has an optimal capacity of 30,000 kW. In this case, CHP shares 275,707 Gcal and 72.8% of heat production, while peak load boiler PLB shares 103,240 Gcal and 27.2%. In the CHP, fuel cell, and photovoltaic combinations, the optimum capacity is 30,000 kW, 5,000 kW, and 1,980 kW, respectively. At this time, CHP shared 275,940 Gcal, 72.8%, fuel cell 12,390 Gcal, 3.3%, and PLB 90,620 Gcal, 23.9%. The CHP capacity was not reduced because an uneconomical alternative was found that required excessive operation of the PLB for insufficient heat production resulting from the CHP capacity reduction. On the other hand, in terms of indirect heat demand for the paper industry, which is the dominant industry, the optimal capacity of CHP, fuel cell, and photovoltaic combination is 25,000 kW, 5,000 kW, and 2,000 kW. The heat production was analyzed to be CHP 225,053 Gcal, 76.5%, fuel cell 11,215 Gcal, 3.8%, PLB 58,012 Gcal, 19.7%. However, the economic analysis results of the current electricity market and gas market confirm that the return on investment is impossible. However, we confirmed that the CHP Hybrid System, which combines CHP, fuel cell, and solar power, can improve management conditions of about KRW 9.3 billion annually for a single CHP system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.1-2
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• 2011

Hybrid rockets have lately attracted attention as a strong candidate of small, low cost, safe and reliable launch vehicles. A significant topic is that the first commercially sponsored space ship, SpaceShipOne vehicle chose a hybrid rocket. The main factors for the choice were safety of operation, system cost, quick turnaround, and thrust termination. In Japan, five universities including Hokkaido University and three private companies organized "Hybrid Rocket Research Group" from 1998 to 2002. Their main purpose was to downsize the cost and scale of rocket experiments. In 2002, UNISEC (University Space Engineering Consortium) and HASTIC (Hokkaido Aerospace Science and Technology Incubation Center) took over the educational and R&D rocket activities respectively and the research group dissolved. In 2008, JAXA/ISAS and eleven universities formed "Hybrid Rocket Research Working Group" as a subcommittee of the Steering Committee for Space Engineering in ISAS. Their goal is to demonstrate technical feasibility of lowcost and high frequency launches of nano/micro satellites into sun-synchronous orbits. Hybrid rockets use a combination of solid and liquid propellants. Usually the fuel is in a solid phase. A serious problem of hybrid rockets is the low regression rate of the solid fuel. In single port hybrids the low regression rate below 1 mm/s causes large L/D exceeding a hundred and small fuel loading ratio falling below 0.3. Multi-port hybrids are a typical solution to solve this problem. However, this solution is not the mainstream in Japan. Another approach is to use high regression rate fuels. For example, a fuel regression rate of 4 mm/s decreases L/D to around 10 and increases the loading ratio to around 0.75. Liquefying fuels such as paraffins are strong candidates for high regression fuels and subject of active research in Japan too. Nakagawa et al. in Tokai University employed EVA (Ethylene Vinyl Acetate) to modify viscosity of paraffin based fuels and investigated the effect of viscosity on regression rates. Wada et al. in Akita University employed LTP (Low melting ThermoPlastic) as another candidate of liquefying fuels and demonstrated high regression rates comparable to paraffin fuels. Hori et al. in JAXA/ISAS employed glycidylazide-poly(ethylene glycol) (GAP-PEG) copolymers as high regression rate fuels and modified the combustion characteristics by changing the PEG mixing ratio. Regression rate improvement by changing internal ballistics is another stream of research. The author proposed a new fuel configuration named "CAMUI" in 1998. CAMUI comes from an abbreviation of "cascaded multistage impinging-jet" meaning the distinctive flow field. A CAMUI type fuel grain consists of several cylindrical fuel blocks with two ports in axial direction. The port alignment shifts 90 degrees with each other to make jets out of ports impinge on the upstream end face of the downstream fuel block, resulting in intense heat transfer to the fuel. Yuasa et al. in Tokyo Metropolitan University employed swirling injection method and improved regression rates more than three times higher. However, regression rate distribution along the axis is not uniform due to the decay of the swirl strength. Aso et al. in Kyushu University employed multi-swirl injection to solve this problem. Combinations of swirling injection and paraffin based fuel have been tried and some results show very high regression rates exceeding ten times of conventional one. High fuel regression rates by new fuel, new internal ballistics, or combination of them require faster fuel-oxidizer mixing to maintain combustion efficiency. Nakagawa et al. succeeded to improve combustion efficiency of a paraffin-based fuel from 77% to 96% by a baffle plate. Another effective approach some researchers are trying is to use an aft-chamber to increase residence time. Better understanding of the new flow fields is necessary to reveal basic mechanisms of regression enhancement. Yuasa et al. visualized the combustion field in a swirling injection type motor. Nakagawa et al. observed boundary layer combustion of wax-based fuels. To understand detailed flow structures in swirling flow type hybrids, Sawada et al. (Tohoku Univ.), Teramoto et al. (Univ. of Tokyo), Shimada et al. (ISAS), and Tsuboi et al. (Kyushu Inst. Tech.) are trying to simulate the flow field numerically. Main challenges are turbulent reaction, stiffness due to low Mach number flow, fuel regression model, and other non-steady phenomena. Oshima et al. in Hokkaido University simulated CAMUI type flow fields and discussed correspondence relation between regression distribution of a burning surface and the vortex structure over the surface.

• Journal of Science of Art and Design
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• v.8
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• pp.63-94
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• 2005

ChangSayng-Do in the late Chosun dynasty was a kind of traditional painting which sublimated the philosophy and emotion of everyday life into an aesthetic consciousness through a long history of Korean people . It would represent a human wish and desire to live a long and healthy life, which was implicated by way of Taoism. The major themes of ChangSayng-Do - mountains, the sun, cloud, water, rock, deer, tortoises, cranes, pine trees, bamboos, peaches, and herbs of eternal youth - were all symbols used. to wish for a long-life and immortality in real world. All or some of these items were represented in paintings, which resulted in the various kinds of ChangSayng-Do. The main concern of this thesis will be centered around the naturalistic subjects shown in ChangSayng-Do. This thesis consists of four chapters. The first chapter describes the purpose of and need for the research, and its method and scope. The second chapter deals with the origin and style of ChangSayng-Do, and the background of its formation. It is found out that the formative characteristic of ChangSayng-Do lies in the archetype, the unity of man and nature following the traditional view of nature. It is also found out that ChangSayng-Do implied the notions of Supernatural Being, Yin-Yang and Five Elements, Taoism, and Confucianism as well as Korean shamanism. Third chapter is largely about an analytic investigation into symbolic visualization of ChangSayng-Do. Firstly, the subject matters shown in ChangSayng-Do consist of items of wishful omen for long-life and good luck, and any motif in a picture implies a symbolism of eternal youth and long-life. Secondly, the view of colors shown in ChangSayng-Do is closely connected to Five Elements and Five Direction, a traditional oriental philosophy of universe, and these symbolic colors are based on shamanism and Yin/Yang-Five Elements. According to an iconological analysis, it is confirmed that these viewpoints are consistent with formative principles and expressive methods of ChangSayng-Do to some extent. The fourth chapter is one of the most important elements for visualization of ChangSayng-Do. The symbolic meaning of long life and good luck is the major source of its popularity inside the palace as well as among the people in general. The fact that ChangSayng-Do was used to ornament the palace was documented in $\lceil$UiGuey(documents about Chosun dynasty$\rfloor$. Also during the late period of Chosun dynasty, the appreciators of arts had begun to spread from high level class to lower level class, and many pictures represented in $\lceil$Hanyang-Ga$\rfloor$ were the ones produced and circulated for those increased consumers. As for the folk-artistic characteristics, the anonymity and arbitrary naturalness of ChangSayng-Do demonstrates that the folk-artistic elements were fully soaked into the life styles of people in general. ChangSayng-Do further shows that a human being is located in the center of the universe, and that all the natural phenomena and ecology are observed to happen around human beings, and that the results of those happenings are connected to man's course of life. It is discovered that the subject matters of ChangSayng-Do in the late Chosun dynasty imply another idea inside metaphors and symbols. With regard to the arrangement of time and space, the unity or oneness of oneself with the world is more highly regarded than one's individual subjectivity: there exist multiple times and spaces in a single picture This reveals a wholistic view of oneness which does not permit the division between phenomenon and substance. To conclude, this thesis inquired into ChangSayng-Do in the late Chosun dynasty focusing on the expression of archetype-symbols. And through the analysis and demonstration, this thesis re-established constructional principles and formative characteristics of ChangSayng-Do and then settled a new phase of ChangSayng-Do, with a deep under-standing of fundamental thoughts of Korean people underlying ChangSayng-Do.

• The Journal of Sustainable Design and Educational Environment Research
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• v.21 no.3
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• pp.1-13
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• 2022

This study is a case study to identify the spatial composition and structural problems of existing schools for spatial innovation as a future school that can operate a credit system for old high schools and establish a mid-to-long-term arrangement plan as a credit system operating school capable of various teaching and learning in the future. The study results are as follows: First, most of the problems of the old high schools entailed that there was very poor connectivity between buildings as most of them were arranged in a single, standard design-type unit building and distributed in multiple buildings. In addition, the floor plan of each building is suggested to be a structure in which student exchange and rest functions cannot be achieved during the break period due to the spatial composition of the classroom and hallway concepts. Second, in the direction of the high school space configuration for future school space innovation, the arrangement plan should be established by reflecting the collective arrangement in consideration of the shortening of the movement route and the expansion of subject areas due to the movement of students on the premise of the subject classroom system. Moreover, it is desirable to provide a square-type space for rest and exchange in the central area where communication and exchange are possible according to the moving class. Third, as the evaluation criteria for relocating old high schools, a space program is prepared based on the number of classes in the future, and legal analysis of school land use and land use efficiency analysis considering regional characteristics are conducted. Based on such analysis data, mid-to-long-term land use plans and space arrangement plans for the entire school space such as the school facility complex are established.

• Tuberculosis and Respiratory Diseases
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• v.63 no.3
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• pp.235-241
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• 2007

Background: Airway mucus hypersecretion plays an important role in the pathogenesis of asthma, and is associated with the induction of MUC5AC expression in airway secretion. The MUC5AC gene is highly polymorphic; however, there are few studies about the association between the polymorphisms of the MUC5AC gene and asthma susceptibility or asthma phenotypes. We have investigated the association of MUC5AC promoter polymorphisms with the risk of asthma and asthma phenotypes. Methods: We determined the genotypes of the MUC5AC promoter (-1274G>A) in 78 asthma patients and in 78 age, sex-matched control individuals in the Korean population. Genomic DNAs from blood were analyzed by PCR and RFLP (restriction fragment length polymorphism) determination. We examined $FEV_1$, total eosinophil count, serum IgE level, $PC_{20}$ and the presence of atopy (by a skin test) in asthma patients. Results: The mean age of the patients was $47.7{\pm}16.1$ years and 38.5% were men, and the mean $FEV_1$ was $84.4{\pm}22.3%$ of predicted in the asthma patients. The -1274G>A polymorphism of the MUC5AC promoter in asthma patients was not significantly different as compared with normal individuals (GG 57.7%, AG 34.6% and AA 7.7% in asthma patients vs. GG 56.4%, AG 38.5% and AA 5.1% in control subject, p = 0.752, Cod). Several clinical parameters in asthma patients such as $FEV_1$, total eosinophil count, serum IgE level, $PC_{20}$ and the presence of atopy, were not associated with the -1274G>A polymorphism of the MUC5AC promoter. Conclusion: The -1274G>A single nucleotide polymorphism (SNP) frequency of the MUC5AC promoter was not associated with asthma in a Korean population.

• Asia pacific journal of information systems
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• v.19 no.1
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• pp.113-145
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• 2009

Recently, due to the globalization of the IT(Information Technology) market, devices and systems designed in one country are used in other countries as well. This phenomenon is becoming the key factor for increased interest on cross-cultural, or cross-national, research within the IT area. However, as the IT market is becoming bigger and more globalized, a great number of IT practitioners are having difficulty in designing and developing devices or systems which can provide optimal experience. This is because not only tangible factors such as language and a country's economic or industrial power affect the user experience of a certain device or system but also invisible and intangible factors as well. Among such invisible and intangible factors, the cultural characteristics of users from different countries may affect the user experience of certain devices or systems because cultural characteristics affect how they understand and interpret the devices or systems. In other words, when users evaluate the quality of overall user experience, the cultural characteristics of each user act as a perceptual lens that leads the user to focus on a certain elements of experience. Therefore, there is a need within the IT field to consider cultural characteristics when designing or developing certain devices or systems and plan a strategy for localization. In such an environment, existing IS studies identify the culture with the country, emphasize the importance of culture in a national level perspective, and hypothesize that users within the same country have same cultural characteristics. Under such assumptions, these studies focus on the moderating effects of cultural characteristics on a national level within a certain theoretical framework. This has already been suggested by cross-cultural studies conducted by scholars such as Hofstede(1980) in providing numerical research results and measurement items for cultural characteristics and using such results or items as they increase the efficiency of studies. However, such national level culture has its limitations in forecasting and explaining individual-level behaviors such as voluntary device or system usage. This is because individual cultural characteristics are the outcome of not only the national culture but also the culture of a race, company, local area, family, and other groups that are formulated through interaction within the group. Therefore, national or nationally dominant cultural characteristics may have its limitations in forecasting and explaining the cultural characteristics of an individual. Moreover, past studies in psychology suggest a possibility that there exist different cultural characteristics within a single individual depending on the subject being measured or its context. For example, in relation to individual vs. collective characteristics, which is one of the major cultural characteristics, an individual may show collectivistic characteristics when he or she is with family or friends but show individualistic characteristics in his or her workplace. Therefore, this study acknowledged such limitations of past studies and conducted a research within the framework of 'theoretically integrated model of user satisfaction and emotional attachment', which was developed through a former study, on how the effects of different experience elements on emotional attachment or user satisfaction are differentiated depending on the individual cultural characteristics related to a system or device usage. In order to do this, this study hypothesized the moderating effects of four cultural dimensions (uncertainty avoidance, individualism vs, collectivism, masculinity vs. femininity, and power distance) as suggested by Hofstede(1980) within the theoretically integrated model of emotional attachment and user satisfaction. Statistical tests were then implemented on these moderating effects through conducting surveys with users of four digital devices (mobile phone, MP3 player, LCD TV, and refrigerator) in three countries (US, Germany, and Russia). In order to explain and forecast the behavior of personal device or system users, individual cultural characteristics must be measured, and depending on the target device or system, measurements must be measured independently. Through this suggestion, this study hopes to provide new and useful perspectives for future IS research.

• Proceedings of the Korean Ceranic Society Conference
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• 2005.06a
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• pp.1-112
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• 2005

This report is results of a research on recent R&D trends in electroceramics, mainly focusing on the papers submitted to the organizing committee of the International Conference on Electroceramics 2005 (ICE-2005) which was held at Seoul on 12-15 June 2005. About 380 electroceramics researchers attended at the ICE-2005 from 17 countries including Korea, presenting and discussing their recent results. Therefore, we can easily understand the recent research trends in the field of electroceramics by analyses of the subject and contents of the submitted papers. In addition to the analyses of the papers submitted to the ICE-2005, we also collected some informations about domestic and international research trends to help readers understand this report easily. We analysed the R&D trends on the basis of four main categories, that is, informatics electroceramics, energy and environment ceramics, processing and characterization of electroceramics, and emerging fields of electroceramics. Each main category has several sub-categories again. The informatics ceramics category includes integrated dielectrics and ferroelectrics, oxide and nitride semiconductors, photonic and optoelectronic devices, multilayer electronic ceramics and devices, microwave dielectrics and high frequency devices, and piezoelectric and MEMS applications. The energy and environment ceramics category has four sub-categories, that is, rechargable battery, hydrogen storage, fuel cells, and advanced energy conversion concepts. In the processing and characterization category, there exist domain, strain, and epitaxial dynamics and engineering sub-category, innovative processing and synthesis sub-category, nanostructured materials and nanotechnology sub- category, single crystal growth and characterization sub-category, theory and modeling sub-category. Nanocrystalline electroceramics, electroceramics for smart sensors, and bioceramics sub-categories are included to the emerging fields category. We hope that this report give an opportunity to understand the international research trend, not only to Korean ceramics researchers but also to science and technology policy researchers.

• The Journal of Korean Society for School & Community Health Education
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• v.4
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• pp.117-139
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• 2003

The purpose of this research lies in presenting logical viability for the measures that curtail access to lewd Internet contents by middle school students amidst the reality in which lewd contents are circulated freely through the Internet, a medium that the middle school students find most easy to access. In order to establish right form of awareness towards sex, this research identified the ways they access the lewd Internet contents, their reaction after the exposure to those contents, their knowledge of sex, their concerns regarding sex and their accessibility to sexual activities in order to conduct a comparative analysis on the relationship between lewd Internet contents and their awareness of sex. First, realities of accessing lewd Internet contents and reactions according to the demographics of middle school students There isa significant difference in the experience of accessing lewd Internet contents in terms of gender. Mostly, male students tend to access the contents more. As for the way they access the lewd Internet contents, both male and female students replied that they access through spam mail of lewd nature. Thus, measures to address this problem are needed urgently. As to when they first accessed the lewd contents, most of the research subjects replied that they accessed either in elementary school period or in the early middle school period. This shows that most of the students got exposed to lewd contents even before they could establish positive, correct awareness of sex. Thus, there is a risk that they may formulate wrong kind of sexual awareness. Accordingly, it is necessary to develop measures through focused sex education. Students are divided into two groups according to the time they spend on the contents averagely: those who spend over one hour and those who spend less than an hour on the lewd contents. If the students spending longer hours are not to be checked and properly guided, it may lead to increasing cases of sexual delinquencies due to their wrongly formed awareness of sex. When the question of existence(non-existence) of guardian was addressed, students with both parents tend to access the lewd Internet contents in a more diverse manner and tend to access more compared to those students from single parent or no-parent families. Accordingly, guardians need to pay attention to how their children are using the Internet. Second, awareness of sex depending on the middle school students' demographics In case of sexual knowledge, middle school students shows relatively high level of knowledge. In particular, female students are found more knowledgeable than male students, and the students in upper years are more knowledgeable as well. As a result, this research recommends that the students in lower years should be guided with more basc and detailed information, while those in upper years need to be taught to form and express their own thoughts and attitudes and to build up independence on this matter. In case of worries about sex, both male and female students don't worry too much about it. However, male students are more concerned about sex than female students in a more diverse ways. As for the differences by academic year, concerns for sex increase, as students get older. Accordingly, sex education that helps establish sound perception of the opposite sex and that focuses on the etiquettes that one must adhere to at the presence of the opposite sex need to be conducted against middle school students. In case of accessibility to sex, male students manifest higher tendency than female students. As for the differences by academic year, those in the first and second years show higher accessibility than those in their third year. In general, younger students tend to be more open-minded toward sex. Accordingly, students in lower academic years need to undergo basic knowledge oriented sex education, whereas those in upper academic years need to undergo discussion centered sex education where they subject to questions regarding their attitude and opinion. Third, relationship between the reactions after the exposure to the lewd Internet contents and their awareness of sex As the frequency of contact with lewd Internet contents increases, awareness of sex increases as well. Thus, the lewd Internet contents contribute to the increase in students' concern for sex as well as increase in accessibility to sex, which eventually become barriers to students' establishment of a healthy perception of sex. Reactions to sex after the exposure to lewd Internet contents and awareness of sex indicate a significant correlation. However, negative correlation is manifested with knowledge of sex. Thus, it is possible to know that the greater access to lewd Internet contents does not necessarily translate into increase in knowledge of sex. However, the study showed there is a correlation between concerns for sex and the level of accessibility to sex. In more detail, the more reactions to the contents they show, the more concerns for sex they have and the more positively they take acceptability to sex. Moreover, it is necessary to develop necessary measures since textbooks today do not include measures needed to address the lewd Internet contents. Given the above findings, it is necessary to continue to complement structural measures in order to prevent easy access of lewd Internet contents by middle school students. Moreover, it is necessary to be considerate of the students so that they themselves can form a healthy Internet culture and grow up within positive framework for the sex education.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.69-77
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• 2005

The purposes of this study were to develop and introduce a novel intraoral appliance for bruxism composed of power switch and biofeedback device and further to examine inter- and intra-reliability of the appliance prior to clinical tests. The newly-developed appliance consisted of detection sensors, a central processing unit (CPU), a reactor and a storage unit and a displayer. Compact-sized, waterproof switches were selected as bruxism detection sensor and any sensor activation by clenching or grinding event was processed at the CPU and transmitted, by radio wave, to the reactor and storage unit and triggered auditory or vibratory signal, subsequently producing biofeedback to the patient with bruxism. The data on bruxing event in the storage unit can be displayed on the computer, making it possible analyzing frequency, duration and nature of bruxism. Cast models were obtained from ten volunteers with normal occlusion to evaluate reliability of the appliances. For inter-operator reliability on the intraoral appliances, each operator of the two fabricated the appliance for the same subject and compared the minimal contact forces provoking auditory biofeedback reaction in vertical, lateral and central directions. Intra-operator reliability was also investigated on the appliances made by a single operator at two separate times with an interval of two days. Conclusively, the newly-developed appliance is compact and safe to use in oral circumstance and easy to make. Furthermore, it had to be proven reliability excellent enough to apply in clinical settings. Thus, it is assumed that this appliance with the processor and the storage of data and auditory or vibratory biofeedback function is available and useful to analyze and control bruxism.