• The Korean Journal of Nuclear Medicine
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• v.36 no.1
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• pp.1-7
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• 2002

Positron Emission Tomography (PET) is a nuclear medicine imaging modality that consists of systemic administration to a subject of a radiopharmaceutical labeled with a positron-emitting radionuclide. Following administration, its distribution in the organ or structure under study can be assessed as a function of time and space by (1) defecting the annihilation radiation resulting from the interaction of the positrons with matter, and (2) reconstructing the distribution of the radioactivity from a series of that used in computed tomography (CT). The nuclides most generally exhibit chemical properties that render them particularly desirable in physiological studies. The radionuclides most widely used in PET are F-18, C-11, O-15 and N-13. Regarding to the number of the current PET Centers worldwide (based on ICP data), more than 300 PET Centers were in operation in 2000. The use of PET technology grew rapidly compared to that in 1992 and 1996, particularly in the USA, which demonstrates a three-fold rise in PET installations. In 2001, 194 PET Centers were operating in the USA. In 1994, two clinical and research-oriented PET Centers at Seoul National University Hospital and Samsung Medical Center, was established as the first dedicated PET and Cyclotron machines in Korea, followed by two more PET facilities at the Korea Cancer Center Hospital, Ajou Medical Center, Yonsei University Medical Center, National Cancer Center and established their PET Center. Catholic Medical School and Pusan National University Hospital have finalized a plan to install PET machine in 2002, which results in total of nine PET Centers in Korea. Considering annual trends of PET application in four major PET centers in Korea in Asan Medical Center recent six years (from 1995 to 2000), a total of 11,564 patients have been studied every year and the number of PET studies has shown steep growth year upon year. We had 1,020 PET patients in 1995. This number increased to 1,196, 1,756, 2,379, 3,015 and 4,414 in 1996,1997,1998,1999 and 2000, respectively. The application in cardiac disorders is minimal, and among various neuropsychiatric diseases, patients with epilepsy or dementia can benefit from PET studios. Recently, we investigated brain mapping and neuroreceptor works. PET is not a key application for evaluation of the cardiac patients in Korea because of the relatively low incidence of cardiac disease and less costly procedures such as SPECT can now be performed. The changes in the application of PET studios indicate that, initially, brain PET occupied almost 60% in 1995, followed by a gradual decrease in brain application. However, overall PET use in the diagnosis and management of patients with cancer was up to 63% in 2000. The current medicare coverage policy in the USA is very important because reimbursement policy is critical for the promotion of PET. In May 1995, the Health Care Financing Administration (HCFA) began covering the PET perfusion study using Rubidium-82, evaluation of a solitary pulmonary nodule and pathologically proven non-small cell lung cancer. As of July 1999, Medicare's coverage policy expanded to include additional indications: evaluation of recurrent colorectal cancer with a rising CEA level, staging of lymphoma and detection of recurrent or metastatic melanoma. In December of 2001, National Coverage decided to expand Medicare reimbursement for broad use in 6 cancers: lung, colorecctal, lymphoma, melanoma, head and neck, and esophageal cancers; for determining revascularization in heart diseases; and for identifying epilepsy patients. In addition, PET coverage is expected to further expand to diseases affecting women, such as breast, ovarian, uterine and vaginal cancers as well as diseases like prostate cancer and Alzheimer's disease.

• Tunnel and Underground Space
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• v.10 no.3
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• pp.447-456
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• 2000

Rock bridge in rock masses can be considered as one of several types of opening-mode fractures, and also it has been known to have a great influence on the stability of structures in rock mass. In the beginning of researching a rock bridge it used to be studied only in characteristics of its behavior, as considering resistance of material itself. However the distribution pattern of rock bridges, which can affect the stability of rock structures, is currently researched with a fracture mechanical approach in numerical studies. For investigating the effect of rock bridges on the development pattern of hydraulic fractures, the author analyzed numerically the stress state transition in rock bridges and their phenomena with a different pattern of the rock bridge distributions. From the numerical studies, a two-crack configuration could be defined to be representative of the most critical conditions for rock bridges, only when cracks are systematic and same in their length and angle. Moreover, coalescence stresses and onset of propagation stresses could be known to increase with decreasing s/L ratio or increasing d/L ratio. The effect of pre-existing crack on hydraulic fracturing was studied also in numerical models. Different to the simple hydraulic fracturing modeling in which the fractures propagated exactly parallel to the maximum remote stress, the hydraulic fractures with pre-existing cracks did not propagate parallel to the maximum remote stress direction. These are representative of the tendency to change the hydraulic fractures direction because of the existence of pre-existing crack. Therefore s/L, d/L ratios will be identical as a function effective on hydraulic fractures propagation, that is, the K$_1$ value increase with decreasing s/L ratio or increasing d/L ratio and its magnification from onset to propagation increases with decreasing s/L ratio. The scanline is a commonly used method to estimate the fracture distribution on outcrops. The data obtained from the scanline method can be applied to the evaluation of stress field in rock mass.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.5
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• pp.13-35
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• 2020

Startup accelerators are a new type of investors providing a certain amount of shares for imparting education, mentoring, networking, and providing space and seed money that can directly resolve the difficulties faced by nascent entrepreneurs (Clarysse, 2016). Startup accelerators have expanded worldwide as their influence over the startup ecosystem has increasingly been established (Pauwels et al., 2016; Cohen & Hochberg, 2014). This study was conducted to derive investment determinants of startup accelerators that are emerging as major investment players around the world. To this end, the accelerator-type determinants of investment were derived. As previous research on this topic is nonexistent, this process involved qualitative meta-synthesis, literature reviews, observation, and in-depth interviews. First, more than 30 research papers were examined for the determinants of investment for firms at an early stage of their foundation, and the categories and determinants of investment in the relevant studies were comparatively analyzed using qualitative meta-synthesis. Further, related data were investigated to identify the characteristics of accelerators, and the startup evaluation process of US accelerators was studied. The more than 100 questions raised during this process were coded to examine the determinants of investment that accelerators considered important. In-depth interviews were conducted with four US accelerators to identify the characteristics of accelerators and key determinants of investment. Ultimately, 5 categories of accelerator-type determinants of investment and 26 subordinate determinants of investment were derived. The results were verified and supplemented by consulting with seven accelerators in Korea. The results were confirmed after pilot tests and verification by seven domestic accelerators. After confirming the accelerator-type determinants, the reliability of them was verified by examining the importance and priority of each category through the quantitative survey of Korean accelerators. The research that elicited the accelerator-type investment determinants is the first research and is expected to be a major reference to the progress of subsequent studies. This research that systematically derived the investment determinants of the accelerator is expected to make major contributions to the progress of follow-up studies, the process of selecting startups, and the investment decision-making process of the accelerators.

• The Journal of Art Theory & Practice
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• no.7
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• pp.37-64
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• 2009

The theories of Korean Public Art originated by the artists who were against dictatorship and they associated with democratic politicians. They criticized the Fine art that were supported by the dictatorship and gave their efforts for restoration of 'resistance paintings(against dictatorship)', 'proletarian painting', 'realism painting'. In addition, they participated new social ideology(democracy) movement and demonstrated for their rights in arts. These became the main kernel the public art theory was initiated. The public artists splitted into several different parts and participated in the democratic social movement as well as the art movement for freedom. They opened various art exhibitions within different genre, diverse space for various art section such as an exhibition hall, a factories, a university, or a congregation square. Furthermore, the public art theorists published their divergent views through newspaper/broadcasting or unauthorized printed materials. Most of the public artist and the theorists kept their relationship strongly until 1985, the time when 'National Arts Association' started. In 1983 and 1984, they were clearly separated into two parts; artists(move only in art museums) and activists(move in public spaces like school, convention square etc). Their ideological separation also took out national problems. The division; professional artists and armatures, became the social issue as a social stratification matter. And in creating method, there are also other conflicts; critical realism, and public realism as well as western painting and traditional one. These kinds of separation and conflicts made different Public artists associations, under divergent names; 'Reality and Speak'(R&S), 'KwangJu Art Association', 'Durung', 'Dang(Land)', and 'Local Youth Students Association'. In addition, their ideology and pursuit toward art movements were very difference. However, the differences and conflicts weakened When the oppression of democratic education from new dictatorship(Pres. Jun, Doo Hwan) came out. In August. 1985 the government opened to the public so called, 'The draft of School stabilization law'(Hankwon Anjung Bup) to control the teachers' rights and that initiated bigger street demonstration and conflicts between police and educators. In November.1985, assembly meeting of National Arts Association in democracy opened as 'ONE' combined organization. In this presentation, I'd like to summarize the stream of art movement until 1984, and clarify the main art theories that lead the Public Art Movements in 1980s. The main theories in 1980s are crucial because they become the origin of public art theories. This presentation started with O,youn's "Hyunsil Dong In the first declaration" and explained the absent of practice in 1970s. In addition, Won, Dong Suk 's theory was mentioned as all over struggles in theories before 1980s. GA and R&S 's founding declarations in 1970s were the start of public art theorists' activities and this article reported the activities after the declarations. First, realism base on the consciousness of reality. Second, practice art democratization based on the ideology. Third, the subject of public art movement based on understanding people's social stratification structure. Fourth, the matters of national forms and creative ways in arts based on showing reality. Fifth, the strong points in arts that the practitioners accepted. About the public art theories around 1984, I discussed the dividing point of public art theories that were shown in 'generation theory', 'organization theory', and 'popularization theory' by the practitioners. The public realism theory that subjects the contradiction of reality and point out the limits of critical realism not only showing the new creative ways but also giving the feeling of solidarity to the public art activist groups. After that, public art movements expressed 'Dismentlement of Capitalism' and 'Public revolution'. In addition, the direction of public art movements were established strongly. There were various opinions and views during the start and formation of the public art theories. The foundation of theorists activities derived from the practitioners who had the concept based on stratification and nationalism. The strong trend of group division spreaded out by practitioners who opened art work together in factories, universities, squares and rural areas. Now many lively active practitioners are gone to the other field not related with arts, and others join into professional art field not public art one with unknown reason. The theorists have the same situation with the practitioners. It means to me that theory always have to be based on the practice.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.3
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• pp.21-32
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• 2009

As an alternative for restoring a sense of community which has been broken up due to urban residence redevelopment, this study focuses on structural characteristics according to physical location of central squares in apartment complexes. Central squares do not simply function as inner-aiming and self-completed spaces for the residents, but their role can be expanded to a core location which encourages neighbors to communicate and interact with each other. The suppositions for this study are as follows. Structural characteristics according to the physical locations of the central squares in apartment complexes affect apartment residents' openness toward their neighbors and non-residents' accessibility to the square. At the same time, it influences the sense of community. In addition, psychological distance which is represented as psychological openness and accessibility forms a reciprocal relationship with the sense of community. For the study, we first categorized central squares as either open-structure or closed-structure based on how accessible it is from outside the apartment complex. According to these types of central squares, Sillim Prugio, Banghak Deasang Town Hyundai, Gwanak Prugio and Banghak Samsung Raemian 1 which have similar conditions and different structures were selected as sites of the study. Then each apartment complex was classified by apartment residents and non-residents so that eight groups were prepared for the survey. The results of the questionnaire survey especially regarding measuring the sense of community, psychological openness and accessibility indicated that the suppositions were right. Hence, the sense of community, psychological openness and accessibility are high in a central square with an open-structure while high standards of psychological openness and accessibility guarantee a positive sense of community. This study is meaningful in that it verifies that the physical location of central squares is reciprocally related to psychological openness, accessibility and a sense of community. At the same time, this study may serve as theoretical grounds for the planning and construction of practical central squares.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.5
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• pp.134-147
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• 2014

Pleasure grounds, which were introduced during the Japanese colonial era, were places for organizing new amusement activities, and developed into a large-scale private spaces and a new type of public space at the same time. This study explores the scenery and accommodations of pleasure grounds and the changes of the amusement culture through the Wolmido Pleasure Grounds, which was a typical pleasure grounds of the time. At that time, Wolmido became a comprehensive amusement/entertainment place with many elements of both Western and Japanese pleasure grounds such as exotic buildings harmonized with trees, a beach, a seaside school, public playing field, and zoo constructed on the Island. Wolmido Pleasure Ground, which was connected with Kyungsung by Kyungin railroad during the Japanese colonial era, is a good example showing the process of the popularization and commercialization of the amusement culture. The process of popularization of amusement shows the spreading of the enjoyment of leisure time with amusement activities through appreciating the beautiful scenery of the pleasure grounds among various social classes. The caste system was broken and anyone could use the pleasure grounds by paying the fee, of which there were many kinds, so the distinction between genders and the different classes, such as the Chosun people and Japanese, regarding amusement in pleasure grounds disappeared gradually. Also, pleasure grounds were a place for Western hobby-sports activities and were the means to generalize collective and dynamic activities through summer school and various sport games. At the same time, there were places for deviation from the existing social norms when it was combined with entertainment facilities. The commercialization of amusement took place in the form of an artificial entertainment culture within an artificial environment. First, the scenery was artificially constructed and this scenery created the image of paradise such as 'captivating summer vacation spot' and 'water kingdom'. This was the result of the combined intentions of the colonial authority, the railroad company and the amusement corporation to produce economic profits and encourage development in the area. Second, an artificial spectacle was constructed using nature as the backdrop. Buildings of various styles created a modernized and exotic image when they were combined with each other. Artifacts such as breakwaters and arcades created new attractions for people that enabled them to view both nature and the crowds from a whole different perspective. Third, pleasure grounds contributed to the advent of passive users who would just follow the given use and instructions. In this way, one can find the prototype of popular entertainment places of today such as sightseeing complexes, amusement parks, and theme parks through the construction of amusement grounds as a place for providing dynamic activities.

• Korean Journal of Heritage: History & Science
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• v.53 no.1
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• pp.184-203
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• 2020

The Confucian ruling class of the Joseon Dynasty regarded Buddhist rituals as "dangerous festivals." However, these Buddhist ceremonies facilitated transitions between phases of life from birth till death and strengthened communal unity through their joint practice of the rites. Ritual spaces were decorated with various utensils and objects that transformed them into wondrous arenas. Of these ornaments, Buddhist paintings served as the most effective visual medium for educating the common people. As an example, a painting of the Ten Kings of the Underworld (siwangdo) could be hung as a means to illustrate the Buddhist view of the afterlife, embedded in images not only inside a Buddhist temple hall, but in any space where a Buddhist ritual was being held. Demand for Buddhist paintings rose considerably with their use in ritual spaces. Nectar ritual paintings (gamnodo), including scenes of appeasement rites for the souls of the deceased, emphasized depictions of royal family members and their royal relatives. In Chinese paintings of the water and land ceremony (suryukjae), these figures referred to one of several sacred groups who invited deities to a ritual. However, in Korean paintings of a nectar ritual, the iconography symbolized the patronage of the royal court and underlined the historicity and tradition of nationally conducted water and land ceremonies. This royal patronage implied the social and governmental sanction of Buddhist rituals. By including depictions of royal family members and their royal relatives, Joseon Buddhist paintings highlighted this approval. The Joseon ruling class outwardly feared that Buddhist rituals might undermine observance of Confucian proprieties and lead to a corruption of public morals, since monks and laymen, men and women, and people of all ranks mingled within the ritual spaces. The concern of the ruling class was also closely related to the nature of festivals, which involved deviation from the routines of daily life and violation of taboos. Since visual media such as paintings were considered to hold a special power, some members of the ruling class attempted to exploit this power, while others were apprehensive of the risks they entailed. According to Joseon wangjo sillok (The Annals of the Joseon Dynasty), the Joseon royal court burned Buddhist paintings and ordered the arrest of those who created them, while emphasizing their dangers. It further announced that so many citizens were gathering in Buddhist ritual spaces that the capital city was being left vacant. However, this record also paradoxically suggests that Buddhist rituals were widely considered festivals that people should participate in. Buddhist rituals could not be easily suppressed since they performed important religious functions reflecting the phases of the human life cycle, and had no available Confucian replacements. Their festive nature, unifying communities, expanded significantly at the time. The nectar ritual paintings of the late Joseon period realistically delineated nectar rituals and depicted the troops of traveling actors and performers that began to emerge during the seventeenth century. Such Buddhist rituals for consoling souls who encountered an unfortunate death were held annually and evolved into festivals during which the Joseon people relieved their everyday fatigue and refreshed themselves. The process of adopting Buddhist rituals-regarded as "dangerous festivals" due to political suppression of Buddhism in the Confucian nation-as seasonal customs and communal feasts is well reflected in the changes made in Buddhist paintings.

• Journal of the Mineralogical Society of Korea
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• v.15 no.2
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• pp.104-113
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• 2002

The sorption of Cd$^{2+}$ on calcite was studied in aqueous solutions of several electrolytes. The Cd$^{2+}$ concentration, 10$^{-8}$ M, was kept well below saturation with respect to CdCO$_3$(s). Sorption behavior of Cd$^{2+}$ in different ionic strengths of NaClO$_4$solutions shows that sorption is independent of ionic strength. This result suggests that Cd$^{2+}$ sorption on calcite surface is of a specific nature, and adsorption is controlled by an inner-sphere type of surface complex. Two stages in the sorption behavior could be identified: an initial rapid uptake, followed by slower uptake reaching a maximum steady state by 145 hrs. No evidence was observed for surface precipitation, although it can not be entirely ruled out. Desorption of Cd$^{2+}$ from the calcite surface after resuspension into Cd-free solution is initially very rapid, but depends partly on the previous sorption history. Desorption behavior of Cd$^{2+}$ show that an initial rapid desorption followed either by slow uptake reaching a maximum, as in the adsorption experiments, or slowing desorption to reach a steady state minimum. This irreversible behavior of Cd$^{2+}$ sorption and desorption may act as one of the controls for regulating the mobility of dissolved Cd$^{2+}$ natural aqueous systems. Calculated adsorption partition coefficients suggest that overall sorption and desorption process in the concentration range are controlled by d single mechanism.ingle mechanism.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.1
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• pp.49-58
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• 2010

This study is attempted to establish the concept of Byeulseo Scenic Spot that the definitions of Byeulseo and Scenic Spot would be presented first followed by clarifying the basis, reason and justification that Byeulseo would be called as Byeulseo Scenic Spot that the following is the major results formulated herein. First, the concept of scenic spot under the Cultural Property Act is the reference to the famous site with the building improvement well known for its great scenery or the point where splendid scenery is viewed that has the artistic value along with the trace of human lives in this cultural heritage that, although the scenery is important but the attention has to be on discovery of historic resources with the story telling in the subject site. Second, the criteria of designation on the Scenic Spot in Korea would be natural scenery, animal and plant site with well-known scenery, view point of scenery, famous building or garden and important places with legend that there lacks diversification. In this aspect, the intent of the concept of Scenic Spot would be facilitated to expand the designation of the Byeulseo Scenic Spot as the Scenic Spot of living style. Third, from the foreign cases, particularly, in Japan, it is needed to note that Byeulseos and housing gardens are designated for 196 places of Scenic Spot, reaching 55.4% of entire Scenic Spots. Laws, regulations, systems and designated criteria on the cases of designating the foreign Scenic Spots would be studied and quoted. Fourth, the classification work for each type to designate as cultural heritage has to be continued as the Scenic Spot of subject site with even more emerged for the value as the Scenic Spot in garden, original site and the like classified as historic site, important folk data and the like. Fifth, the designation of Scenic Spot of Byeulseo garden with splendid scenery as the living Scenic Spot has to be expanded. The pavilion existed now nationwide would be approximately 1,500, and these pavilions are the place where the scholars stay in the famous site, and this is the central space of Byeulseo to study, and if there is clear one that has written and record of deed to create the stories to people with the value for publicity campaign, it would be the subject of Scenic Spot. And sixth, for the case of view point with splendid scenery in Byeulseo Garden, it cannot be the subject of designation that the designation of Scenic Spot has to be expanded. In the event of the Byeulseo garden in Korea, there are many cases of having outstanding view points, and there is a few case of designating the subject site with great view point as a Scenic Spot.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.32 no.3
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• pp.58-68
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• 2014

Christian Cay Lorenz Hirschfeld is often regarded as 'a father of landscape garden art.' He was an aesthetics professor and garden theoretician in the $18^{th}$ century. He put forth the most comprehensive garden theory book in five volumes between 1779 and 1785. His book, Theorie der Gartenkunst, was translated and widely circulated in his contemporary. The book, which dealt with diverse aspects of garden art such as history, design, material, and type, urged to promote the prevalence of landscape garden in European continents as well as in Germany. However, there have scarcely been discourses in the Hirschfeld's garden theory. This essay aims to review Hirschfeld's garden thoughts in his book critically and to reinterpret some issues in the contemporary landscape theory and practice. Hirschfeldian theory was the product of $18^{th}$ century German Enlightenment and romanticism. At that time, Nature was regarded as divine realm. There was a German affinity with natural world. The spread of reading culture and the fashion of travel literature were another background of the success of his garden literature. Several issues in Hirschfeld garden theory will discussed here. First, privileging garden art was the most significant contribution in his theory. He emphasized that garden art was the most advanced art form among all art genres. Second, garden art was grounded on the mimesis of nature. The ambiguous relationship between nature and art still existed in garden making. However, garden art can be flourished when utilizing the potency of nature in itself. Third, there was the association between the image and the idea in experiencing the garden. Some garden scenes stimulated the related emotional responses such as cheerful and merry, softly melancholic, romantic, solemn etc. Fourth, the movement was the essential aspect of garden art. Motion and emotion are come together in garden experience. To represent the landscape garden style in suitable way, the sketch or image seems to be preferable than the plans and views. Finally, garden art was composing of not only the physical space but also the spirit of place. He maintained the garden art as hortus moralis should be a social metaphor. Hirschfeldian garden theory has often been criticized as the lack of practical power and the old fashioned idea. However, his theory influenced on formulating the idea of public park in $19^{th}$ century. Moreover, there are still some visionary aspects of his theory such as the reevaluation of garden art, the emphasis of locality and the introduction of Mittelweg idea. Recently, gardening culture are prevalent in various realms of art and life. Hirschfeld's garden theory as humanistic landscape theory can provide us some insights in the contemporary practices.