• 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.

• The Korean Society of Law and Medicine
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• v.21 no.2
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• pp.75-103
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• 2020

There is a growing voice that medical information should be shared because it can prepare for genetic diseases or cancer by analyzing and utilizing medical information in big data or artificial intelligence to develop medical technology and improve patient care. The utilization and protection of patients' personal information are the same as two sides of the same coin. Medical institutions or medical personnel should take extra caution in handling personal information with high environmental distinct characteristics and sensitivity, which is different from general information processors. In general, the patient's personal information is processed by medical personnel or medical institutions through the processes of collection, creation, and destruction. Still, the use of terms related to personal information in the Medical Service Act is jumbled, or the scope of application is unclear, so it relies on the interpretation of precedents. For the medical personnel or the founder of the medical institution, in the case of infringement of Article 24(4), it cannot be regarded that it means only medical treatment information among personal information, whether or not it should be treated the same as the personal information under Article 23, because the sensitive information of patients is recorded, saved, and stored in electronic medical records. Although the prohibition of information leakage under Article 19 of the Medical Service Act has a revision; 'secret' that was learned in business was revised to 'information', but only the name was changed, and the benefit and protection of the law is the same as the 'secret' of the criminal law, such that the patient's right to self-determination of personal information is not protected. The Privacy Law and the Local Health Act consider the benefit and protection of the law in 'information learned in business' as the right to self-determination of personal information and stipulate the same penalties for personal information infringement such as leakage, forgery, alteration, and damage. The privacy regulations of the Medical Service Act require that the terms be adjusted uniformly because the jumbled use of terms can confuse information subjects, information processors, and shows certain limitations on the protection of personal information because the contents or scope of the regulations of the Medical Service Law for special corporations and the Privacy Law may cause confusion in interpretation. The patient's personal information is sensitive and must be safely protected in its use and processing. Personal information must be processed in accordance with the protection principle of Privacy Law, and the rights such as privacy, freedom, personal rights, and the right to self-determination of personal information of patients or guardians, the information subject, must be guaranteed.

• Cross-Cultural Studies
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• v.47
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• pp.191-216
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• 2017

Among 20th century Western ideologies (Western civilization), existentialism is a spirit of the times to restore humanity as rationality and advanced technology have driven mankind to impoverishment and death, experiencing the First and Second World War, Great Depression, Fascism and the Spanish Civil War. In his literature, $Andr{\acute{e}}$ Malraux records his existential agony of how mankind lives and faces death by questioning the fateful life and death of characters. For Malraux's characters, the absurdity of existence related to the human identity means self-examination. Malraux explores existential consciousness and actions of characters in the presence of a concept known as death relative to terror, revolution, and adventure. Malraux deftly addresses the concept of death in his literary works, and it has being emphasized as a central subject for philosophical speculation. In Les $Conqu{\acute{e}}rants$(1928), La Voie Royale(1930), La Condition Humaine (1933), L'Espoir(1937), Malraux suggested a philosophical thesis of the meaning of life through characters in tragic situations, and sought out the consciousness of being and the existential meaning through how the characters control their fate. Malraux, in such a tragic perspective of the world, portrays humanity, affirmation of life, and characters' consciousness and actions in denying death. The agony of death triggers escapist behavior such as having unpredictable instinctual desires such as gambling or smoking opium, but these are desperate struggles to flee from frustration and related to the question of one's existence. What is always emphasized with respect to Malraux's existentialism is the tragic metaphysics of the inevitable destiny of the human condition eventually leading to the question of how humans ultimately confront death. But as characters unite in times of war, revolution and adventure in the novel, such cooperative actions symbolizes a keen sense of solidarity reflecting a camaraderie that transcends individualism. Fellowship among people who voluntarily gather for the common cause of philanthropy and restoring humanity is possible because of the underlying human greatness to sacrifice for such a noble cause. Therefore, Malraux's camaraderie includes the victory of existentialism in creating a world of humanism.

• Cross-Cultural Studies
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• v.52
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• pp.277-312
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• 2018

First-order cybernetics during the 1940s and 1950s aimed for control of an observed system, while second-order cybernetics during the mid-1970s aspired to address the mechanism of an observing system. The former pursues an objective, subjectless, approach to a system, whereas the latter prefers a subjective, personal approach to a system. Second-order observation must be noted since a human observer is a living system that has its unique cognition. Maturana and Varela place the autopoiesis of this biological system at the core of second-order cybernetics. They contend that an autpoietic system maintains, transforms and produces itself. Technoscientific recreation of biological autopoiesis opens up to a new step in cybernetics: what I describe as third-order cybernetics. The formation of technoscientific autopoiesis overlaps with the Fourth Industrial Revolution or what Erik Brynjolfsson and Andrew McAfee call the Second Machine Age. It leads to a radical shift from human centrism to posthumanity whereby humanity is mechanized, and machinery is biologized. In two versions of the novel Demon Seed, American novelist Dean Koontz explores the significance of technoscientific autopoiesis. The 1973 version dramatizes two kinds of observers: the technophobic human observer and the technology-friendly machine observer Proteus. As the story concludes, the former dominates the latter with the result that an anthropocentric position still works. The 1997 version, however, reveals the victory of the techno-friendly narrator Proteus over the anthropocentric narrator. Losing his narrational position, the technophobic human narrator of the story disappears. In the 1997 version, Proteus becomes the subject of desire in luring divorcee Susan. He longs to flaunt his male egomaniac. His achievement of male identity is a sign of technological autopoiesis characteristic of third-order cybernetics. To display self-producing capabilities integral to the autonomy of machinery, Koontz's novel demonstrates that Proteus manipulates Susan's egg to produce a human-machine mixture. Koontz's demon child, problematically enough, implicates the future of eugenics in an era of technological autopoiesis. Proteus creates a crossbreed of humanity and machinery to engineer a perfect body and mind. He fixes incurable or intractable diseases through genetic modifications. Proteus transfers a vast amount of digital information to his offspring's brain, which enables the demon child to achieve state-of-the-art intelligence. His technological editing of human genes and consciousness leads to digital standardization through unanimous spread of the best qualities of humanity. He gathers distinguished human genes and mental status much like collecting luxury brands. Accordingly, Proteus's child-making project ultimately moves towards technologically-controlled eugenics. Pointedly, it disturbs the classical ideal of liberal humanism celebrating a human being as the master of his or her nature.

• The Korean Journal of Archival Studies
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• no.21
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• pp.3-40
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• 2009

It has passed ten years since modern records and archives management in our country launched. During times, it has dramatically developed in the fields of law, institution and education. However a study on the definition of records and archives was non be studied enough compared to development of various research fields. In fact the reason why study on the definition was non fulfilled is that some aspects such as historical, informational, archival perspective have been coexisting without order in Korea. This situation is the biggest barrier that archival science is to a disciplinary field. Historically, 'archivium' in Latin language had developed in starting of its means place, then whole entity of documents and those organic relations. In this point, archives is rigidly separate to material of Historical science which covers all of recorded. Unlike information which is produced in the process of intended themes and following its outputs like books, documents in archival science is made in the natural process of work. In addition, historical archives which finished the current and semi-current stage and transfer to the institute of permanent conservation after the process of selection so that it is historical and cultural value to satisfy its purpose of making. This changed trend is based on the Second World War and necessity of North American society which needs to effciency and transparency of work. In Korea, records and archives management has been dominantly affected by North American society and become a subject of not arrangement but of classification, not of transferring but of collection. It is also recognized as management of on formation on the all recorded or documents not as an whole documents and all organic relations. But the original type of recognition is the only technology, it cannot have dignity as a field of science.

• The Korean Journal of Archival Studies
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• no.20
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• pp.151-212
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• 2009

Museums are producing new value and being redefined as places that reproduce context, as the process of globalization are being reflected in museum activities. The new additional functions and roles to the traditional mission of museums allow artworks to find potential functions of art archive and meseum. At the same time, the public has faced originality and aura of an artwork by viewing the physical subject. However, with the appearance of a new digital object, the initiative of viewing has moved over from the artwork to the hands of the public. Now, the public does not go to the museum to see an artwork, but has started to adopt to an opposite paradigm of bringing the artwork forward to the screen. Therefore, they are not satisfied any longer with just seeing an artwork, but demand more information about the artworks and reproduce it as knowledge. Therefore, this study aimed to find types and characteristics through definition and range selection of art archive at this point where the value of art archive is enhanced and systematic management is required, and to present record management methods according to art archive structure and core execution function. It especially stressed that the basis of overall art archive definition was in an 'approach' paradigm rather than a 'preservation' paradigm, and embodied various application methods of digitalized art records. The digital object of an artwork was recognized as the first materialization of an actual artwork, and the digital original of an artwork was presented as the core record. Art archive managed under physical and intellectual control were organically restructured focusing on digital original copies of artworks, which are the core record in a digital technology environment, and could be provided to users in forms of various services that meet their demands. The beginning of systematic management of such art records will become a first step to enhance historical value, establish art cultural identity, and truly possess art culture.

• Analytical Science and Technology
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• v.31 no.6
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• pp.240-246
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• 2018

The present study analyzed standard samples of three types of aluminum matrix certified reference materials (CRM) using GD-MS. Calibration curves were constructed for 13 elements (Mg, Si, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Sn, and Pb), with the slope representing the relative sensitivity factor (RSF). The x- and y-axes of the calibration curve represented ion beam ratio (IBR) and the authenticated value of the standard sample, respectively. In order to evaluate precision and linearity of the calibration curve, RSD and the coefficient of determination were calculated. Curve RSD for every element reflected high precision (within 10 %). For most elements, the coefficient of determination was ${\geq}0.99$, indicating excellent linearity. However, vanadium, nickel, and gallium curves exhibited relatively low linearity (0.90~0.95), likely due to their narrow concentration ranges. Standard RSF was calculated using the slope of the curve generated for three types of CRM. Despite vanadium, nickel, and gallium exhibiting low coefficients of determination, their standard RSF resembled that of the three types of CRM. Therefore, the RSF method may be used for element quantitation. Standard iron matrix samples were analyzed to verify the applicability of the aluminum matrix standard RSF, as well as to calculate the RSD-estimated error of the measured value relative to the actual standard value. Six elements (Al, Si, V, Cr, Mn, and Ni) exhibited an RSD of approximately 30 %, while the RSD of Cu was 77 %. In general, Cu isotopes are subject to interference: $^{63}Cu$ to $^{54}Fe^{2+}-^{36}Ar$ and $^{65}Cu$ to $^{56}Fe-Al^{3+}$ interference. Thus, the influence of these impurities may have contributed to the high RSD value observed for Cu. To reliably identify copper, the resolution should be set at ${\geq}8000$. However, high resolutions are inappropriate for analyzing trace elements, as it lowers ion permeability. In conclusion, quantitation of even relatively low amounts of six elements (Al, Si, V, Cr, Mn, and Ni) is possible using this method.

• Korean Journal of Heritage: History & Science
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• v.45 no.1
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• pp.148-173
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• 2012

The rear garden in Donggwol Palace which shared with the Changdeok Palace and the Changgyeong Palace is the salient places of technology and idea reflected the phases of the times of the Joseon Dynasty, so it is certainly one of the best Korean garden cultures. The rear garden in Donggwol which was not only the secret garden for the rest of royal family but also used as symbolic places for the various ceremonies and training its human resources has been considerably destroyed through the period of Japanese colonial rule. Thus the rear garden areas at north of Changkyung Palace were entirely transformed and a few territory from Juhabru(宙合樓) to Ongnyucheon(玉流川) keep up its surviving as the rear garden. The area of Jondeokjeong(尊德亭) which become subject on this studies from among these was constructed as flower garden after development of Ongnyucheon. The areas of Simchujeong(深秋亭), Cheoknoedang(滌惱堂), Pyemwoosa(?愚?), Mangchunjeong(望春亭), Chunhyagak(天香閣), Chungsimjeong(淸心亭) around Jondeokjeong, were situated among the beautiful scenery with the flowers and ponds. But there are only Jondeokjeong and Pyemwoosa at this moment, and the other pavilions was destroyed and transformed. For these reasons, in this studies, the formative purposes were investigated through analysing water elements, planting, ornaments and so on. According to these reasons, historical records and realities of garden construction of five pavilions : Simchujeong, Mangchunjeong, Cheoknoedang, Chunhyagak, Chungyeongak(淸燕閣) were considered to give authenticity to the restoration and reorganization as well as to accumulate basic knowledge about the conservation of environment surrounded garden architectures. These pavilions appeared at Gunggwolgi(宮闕志) and Joseonwangzosilok(朝鮮王朝實), but their names were not appeared at Donggwoldo(東闕圖). So they were ascertained through all of literatures on Donggwol Palace. Cheoknoedang and Simchujeong among these buildings could be found out as the existed buildings and the uncertain building at the northwest of Jondeokjeong was estimated as the name to Chunhyagak or Mangchunjeong. And the hypothesis that the wall surrounding Taichungmoon(太淸門) should be belong to Chungyeongak was supported. In addition, the area which did not known in connection with name and use on northeast at the Changdeok Palace, and had regarded as an impasses in the studies of Donggwoldo and the rear garden in Donggwol Palace, but the historical records of using by Yeonsangun(燕山君) and Sukjong(肅宗) were discovered at this study. And it could be uncovered that the obscure spatial space was a separate house only for king and he enjoyed play there unnoticing to others belong to palace.

• Journal of Korean Society of Forest Science
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• v.108 no.3
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• pp.440-453
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• 2019

This study was carried out to investigate the effect of watching a two-dimensional (2D) forest video and a virtual reality (VR) forest video on stress reduction in adults. Experiments were conducted in an artificial climate room, and 40 subjects participated. After inducing stress in the subjects, subjects watched a 2D gray video, 2D forest video, or VR forest video for 5 mins. The autonomic nervous system activity was evaluated continuously in terms of measured heart rate variability during the experiment. After each experiment, the subject's psychological state was evaluated using a questionnaire. The 2D forest video decreased the viewer's stress index, increased HF, and reduced heart rate compared with the 2D gray video. The VR forest video had a greater stress index reduction effect, LF/HF increase effect, and heart rate reduction effect than the 2D gray video. Psychological measurements showed that subjects felt more comfortable, natural, and calm when watching the 2D gray video, 2D forest video or VR forest video. We also found that the 2D forest video and VR forest video increased positive emotions and reduced negative emotions compared to the 2D gray video. Based on these results, it can be concluded that watching the 2D forest and VR forest videos reduces the stress index and heart rate compared with watching the 2D gray video. Thus, it is considered that the 2D forest video increases the activity of the parasympathetic nervous system, and the VR forest video increases the activity of the sympathetic nervous system. The increased activity of the sympathetic nervous system upon watching the VR forest video is judged to be positive sympathetic nerve activity, such as novelty and curiosity, and not negative sympathetic activity, such as stress and tension. The results of this study are expected to be the basis for examining the visual effects of forest healing, with hope that the utilization of VR, the technology of the fourth industrial revolution in the forestry field, will broaden.

• Journal of Intelligence and Information Systems
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• v.25 no.3
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• pp.239-251
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• 2019

Statistical methods such as moving averages, Kalman filtering, exponential smoothing, regression analysis, and ARIMA (autoregressive integrated moving average) have been used for stock market predictions. However, these statistical methods have not produced superior performances. In recent years, machine learning techniques have been widely used in stock market predictions, including artificial neural network, SVM, and genetic algorithm. In particular, a case-based reasoning method, known as k-nearest neighbor is also widely used for stock price prediction. Case based reasoning retrieves several similar cases from previous cases when a new problem occurs, and combines the class labels of similar cases to create a classification for the new problem. However, case based reasoning has some problems. First, case based reasoning has a tendency to search for a fixed number of neighbors in the observation space and always selects the same number of neighbors rather than the best similar neighbors for the target case. So, case based reasoning may have to take into account more cases even when there are fewer cases applicable depending on the subject. Second, case based reasoning may select neighbors that are far away from the target case. Thus, case based reasoning does not guarantee an optimal pseudo-neighborhood for various target cases, and the predictability can be degraded due to a deviation from the desired similar neighbor. This paper examines how the size of learning data affects stock price predictability through k-nearest neighbor and compares the predictability of k-nearest neighbor with the random walk model according to the size of the learning data and the number of neighbors. In this study, Samsung electronics stock prices were predicted by dividing the learning dataset into two types. For the prediction of next day's closing price, we used four variables: opening value, daily high, daily low, and daily close. In the first experiment, data from January 1, 2000 to December 31, 2017 were used for the learning process. In the second experiment, data from January 1, 2015 to December 31, 2017 were used for the learning process. The test data is from January 1, 2018 to August 31, 2018 for both experiments. We compared the performance of k-NN with the random walk model using the two learning dataset. The mean absolute percentage error (MAPE) was 1.3497 for the random walk model and 1.3570 for the k-NN for the first experiment when the learning data was small. However, the mean absolute percentage error (MAPE) for the random walk model was 1.3497 and the k-NN was 1.2928 for the second experiment when the learning data was large. These results show that the prediction power when more learning data are used is higher than when less learning data are used. Also, this paper shows that k-NN generally produces a better predictive power than random walk model for larger learning datasets and does not when the learning dataset is relatively small. Future studies need to consider macroeconomic variables related to stock price forecasting including opening price, low price, high price, and closing price. Also, to produce better results, it is recommended that the k-nearest neighbor needs to find nearest neighbors using the second step filtering method considering fundamental economic variables as well as a sufficient amount of learning data.