• Progress in Medical Physics
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• v.14 no.4
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• pp.211-217
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• 2003

The Principal component analysis (PCA) is a well-known data analysis method that is useful in linear feature extraction and data compression. The PCA is a linear transformation that applies an orthogonal rotation to the original data, so as to maximize the retained variance. PCA is a classical technique for obtaining an optimal overall mapping of linearly dependent patterns of correlation between variables (e.g. neurons). PCA provides, in the mean-squared error sense, an optimal linear mapping of the signals which are spread across a group of variables. These signals are concentrated into the first few components, while the noise, i.e. variance which is uncorrelated across variables, is sequestered in the remaining components. PCA has been used extensively to resolve temporal patterns in neurophysiological recordings. Because the retinal signal is stochastic process, PCA can be used to identify the retinal spikes. With excised rabbit eye, retina was isolated. A piece of retina was attached with the ganglion cell side to the surface of the microelectrode array (MEA). The MEA consisted of glass plate with 60 substrate integrated and insulated golden connection lanes terminating in an 8${\times}$8 array (spacing 200 $\mu$m, electrode diameter 30 $\mu$m) in the center of the plate. The MEA 60 system was used for the recording of retinal ganglion cell activity. The action potentials of each channel were sorted by off­line analysis tool. Spikes were detected with a threshold criterion and sorted according to their principal component composition. The first (PC1) and second principal component values (PC2) were calculated using all the waveforms of the each channel and all n time points in the waveform, where several clusters could be separated clearly in two dimension. We verified that PCA-based waveform detection was effective as an initial approach for spike sorting method.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.4
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• pp.64-74
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• 2010

The study is based on an urban park design that is designed in consideration of the characteristics of Uijeongbu City, applied with adequate functions for the environment and showcasing the unique scenery in relation to the relocation of the US Air Force Camp Falling Water. The bases of the design are: the reasonable convergence of the square and park in consideration of the site characteristics; the application of an urban context as the park is located near a station; and the realization of an eco-friendly space. This study is based on foundation research regarding a review of urban square patterns, particular items in planning in relation to modern urban parks and the adaptability of the park in the future. Regarding space usage, the design is applied with notable ideas that allow the space to make its own characteristics through voluntary user activity in conjunction with the environment that will allow the park to cope with changes in the future, as opposed to a space that users experience through pre-determined programs. Below are the focal points of the design. First, the park is designed as an empty space which may accommodate the urban structural context of and usage patterns for being a field of the city ecology that changes and develops, beyond a passively-created square pattern. Such open spaces have a continuity which allows it to adapt to the development of the city. In addition, the design facilitates spontaneous processes through changes in usage pattern and time. Second, the design includes the message that the park and the city, natural things and artificial things, must communicate and network with each other. Hence the park shall not be an isolated green island within the city, but is an open space accommodating the demands for open area from nearby commercial, public and residential facilities; the park shall include a field that can accommodate a variety of programs. Third, the park is designed to encourage the effect of direct and indirect practical education by reflecting a physical plan as well as interesting experience design methods to lower carbon emissions and to create and maintain an eco-friendly space, the basis of a zero-emissions city.

• Women's Studies Review
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• v.27 no.1
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• pp.3-36
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• 2010

This paper is based on the certain point that 'the indigenous', which have long been occupied by the Asian patriarchy or the local communities, now calls for the repositioning in the feminist context. 'The indigenous', in one part, generally refer to the matured long-standing traditions and practices of certain regional, or local communities, as a mode of a place specific way of endowing the world with integral meaning. In the narrow definition, it points to the particular form of placed based knowledge for survival, for example, the useful knowledge of a population who have lived experiences of the environment. In the other part, 'the indigenous' could be criticized in the gender perspectives because it has been served as an ideological tool for patriarchy and sexism, which have undermined women's body and subjectivity in the name of the Asian traditional community. That's why the feminists with sensitivity to the discourses of it, may perceive it very differently, still hesitating dealing with the problem. However, even if there are tendencies that the conservatives romanticize local traditions and essentialize 'the indigenous', as it were, it does not exist 'out there'. Then, it could be scrutinized in the contemporary context which, especially, needs to seek the possibility towards the alternatively post - develope mental knowledge system. In the face of global economic crisis which might be resulted from the instrumentalized or fragmented knowledge production system, it's holistic conceptions that human, society, and nature should not be isolated from each other. is able to give an insightful thinking. It will work in the restraint condition that we reconceptualize the indigenous knowledge not as an unchanging artefact of a timeless culture, but as a dynamic, living and culturally meaningful system towards the ecofeminstic indigenous knowledge. And then, indigenous renaissance phenomena which empower non-western culture and knowledge system and generate increased consciousness of cultural membership. Thus, this paper argues that the indigenous knowledges which have been underestimated in the western-centered knowledge-power relations, could be reconstructed as a potential resources of ecological civility transnationally which reconnect individuals and societies with nature.

• The Korean Journal of Nuclear Medicine
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• v.38 no.4
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• pp.325-329
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• 2004

Purpose: Usefulness of mouse liver S9 fraction was evaluated for the measurement of the metabolites in the in vitro metabolism study of $^{18}F$-labeled radiotracers. Materials and Methods: Mouse liver S9 fraction was isolated at au early step in the course of microsome preparation. The in vitro metabolism studies were tarried out by incubating a mixture containing the radiotracer, S9 fraction and NADPH at $37^{\ciirc}C$, and an aliquot of the mixture was analyzed at the indicated time points by radio-TLC. Metabolic defluorination was further confirmed by the incubation with calcium phosphate, a bone mimic. Results: The radiotracer $[^{18}F]1$ underwent metabolic defluorination within 15 min, which was consistent with the results of the in vivo method and the in vitro method using microsome. Radiotracer $[^{18}F]2$ was metabolized to three metabolites including $4-[^{18}F]fluorobenzoic$ acid within 60 min. It is likely that the one of these metabolites at the origin of radio-TLC was identical with the one that obtained from the in vivo and in vitro (microsome) method. Compared with the in vitro method using microsome, the method using S9 fraction gave a similar pattern of the metabolites but with a different ratio, which can be explained by the presence of cytosol in the S9 fraction. Conclusion: These results suggest that the findings of the in vitro metabolism studies using S9 fraction can reflect the in vivo metabolism of novel radiotracers in the liver. Moreover, this method can be used as a tool to determine metabolic defluorination along with calcium phosphate absorption method.