• The Korean Journal of Nuclear Medicine
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• v.38 no.6
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• pp.486-491
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• 2004

Purpose: factor analysis and independent component analysis (ICA) has been used for handling dynamic image sequences. Theoretical advantages of a newly suggested ICA method, ensemble ICA, leaded us to consider applying this method to the analysis of dynamic myocardial $H_2^{15}O$ PET data. In this study, we quantified patients' blood flow using the ensemble ICA method. Materials and Methods: Twenty subjects underwent $H_2^{15}O$ PET scans using ECAT EXACT 47 scanner and myocardial perfusion SPECT using Vertex scanner. After transmission scanning, dynamic emission scans were initiated simultaneously with the injection of $555{\sim}740$ MBq $H_2^{15}O$. Hidden independent components can be extracted from the observed mixed data (PET image) by means of ICA algorithms. Ensemble learning is a variational Bayesian method that provides an analytical approximation to the parameter posterior using a tractable distribution. Variational approximation forms a lower bound on the ensemble likelihood and the maximization of the lower bound is achieved through minimizing the Kullback-Leibler divergence between the true posterior and the variational posterior. In this study, posterior pdf was approximated by a rectified Gaussian distribution to incorporate non-negativity constraint, which is suitable to dynamic images in nuclear medicine. Blood flow was measured in 9 regions - apex, four areas in mid wall, and four areas in base wall. Myocardial perfusion SPECT score and angiography results were compared with the regional blood flow. Results: Major cardiac components were separated successfully by the ensemble ICA method and blood flow could be estimated in 15 among 20 patients. Mean myocardial blood flow was $1.2{\pm}0.40$ ml/min/g in rest, $1.85{\pm}1.12$ ml/min/g in stress state. Blood flow values obtained by an operator in two different occasion were highly correlated (r=0.99). In myocardium component image, the image contrast between left ventricle and myocardium was 1:2.7 in average. Perfusion reserve was significantly different between the regions with and without stenosis detected by the coronary angiography (P<0.01). In 66 segment with stenosis confirmed by angiography, the segments with reversible perfusion decrease in perfusion SPECT showed lower perfusion reserve values in $H_2^{15}O$ PET. Conclusions: Myocardial blood flow could be estimated using an ICA method with ensemble learning. We suggest that the ensemble ICA incorporating non-negative constraint is a feasible method to handle dynamic image sequence obtained by the nuclear medicine techniques.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.188-192
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• 2007

Today, the most pivotal issue in the national research and development, and national scientific and technical policy is to overcome uncertainties in the environment of technology development. The social and economic environment around us is at restricted uncertainty (complex system) where order and disorder coexist. Furthermore, the environment of technology development is more complicated. In order to bring about creativity in practices of technology development, we need a paradigm shift towards a new framework for the construction of the national scientific and technical information infrastructure, which entails a shift to creativity, self-organization and dynamic capability. The paradigm shift will lead the present scientific and technical information infrastructure which centers on information sharing, to move towards one that enables information coherence through self-organization. Thus, it is expected that the new Web 3.0 will provide a client-flexible analysis information system that will make information coherence and feedback possible. Through this system, the policy for the construction of a new scientific and technical infrastructure will evolve, which will bring about co-evolution of individual's knowledge through sharing of self-organizaed knowhow.

• Journal of Korea Multimedia Society
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• v.13 no.8
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• pp.1256-1262
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• 2010

The game has been rapidly evolving through various media such as computer, console game machine, cellular phone and PMP based on the advanced development of scientific technology. In terms of demand, the interest in and desire to consume the game as a way of spending people's spare time have been on the increase constantly while the level of income has been improved. Eventually, the game has gradually expanded its scope of supply and demand, has established its own status as one of the media that is scientifically-intensive and has been developed into a game industry, a large-scale industry. Unlike image media, the methods of exposure in PPL are varied in accordance with the genre of games. This study divides the causes that have influence over the effect of PPL in the game into the genre of game and the skill of gamer. The results of the experiment on how much the aforementioned two elements have influence over the effect of PPL are as in the following: It has been demonstrated that the effect of PPL could appear different according to the genre of game and the skill of gamer on the game. Besides, the genre of game that is dynamic in its screen change in the game has relatively lower effect of PPL than that is not dynamic. Meanwhile, the persons who are highly skilled in the game have higher degree of recognition and preference to the inserted PPL than those who are lowly skilled. In this regard, it has given us a theoretical ground that the fees system for PPL ads should be established variously in accordance with the genre of game and the level of online game users.

• Tunnel and Underground Space
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• v.19 no.5
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• pp.432-439
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• 2009

For more reliable estimation of seismic source, attenuation properties and dynamic ground property, site amplification function should be considered. Among various estimation methods, this study used the Nakamura's method (1989) for estimating site amplification characteristics. This method was originally applied to the surface waves of background noise and therefore there are some limitations in applying to general wave energy. However, recently this method has been extended and applied to the S wave energy successfully. This study applied the method to S wave and Coda wave energy, which is equivalent to the backscattered S wave energy. We used more than 60 observed ground motions from 5 earthquakes which were occurred recently, with magnitude range from 3.6 to 5.1. Each station showed characteristic site amplification property in low-, high- and resonance frequencies. Some of the stations showed as high as 4 times of site amplification in the range of specific frequencies, which may imply abnormal small scale geologic strata below the station or development of various trapped modes in the basin structure. Moreover, removal of site amplification can give us more reliable seismic source and attenuation parameters, addition to the seismic hazard estimation.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.529-537
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• 2014

To establish a foundation to objectively interpret Chosun history, we construct people network of the Chosun dynasty. The network shows scale free network properties as if most social networks do. The people network is composed of 1,379 nodes and 3,874 links and its diameter is 14. To analysis of the network dynamics, whole network that is composed of 27 king networks were constructed by adding the first king, Taejo network to the second king, Jeongjong network and then continuously adding the next king networks. Interestingly, betweenness and closeness centralities were gradually decreased but stress centrality was drastically increased. These results indicate that information flow is gradually slowing and hub node position is more centrally oriented as growing the network. To elucidate key persons from the network, k-core and MCODE algorithms that can extract core or module structures from whole network were employed. It is a possible to obtain new insight and hidden information by analyzing network dynamics. Due to lack of the dynamic interacting data, there is a limit for network dynamic research. In spite of using concise data, this research provides us a possibility that annals of the Chosun dynasty are very useful historical data for analyzing network dynamics.

• Journal of the Korean earth science society
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• v.38 no.2
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• pp.161-171
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• 2017

Observed ground motions are composed of three factors such as, seismic source, attenuation, and site amplification effect. Among them, the site amplification characteristics should be considered significantly when estimating seismic source and attenuation characteristics with more confidence. The site effect is also necessary when estimating not only seismic hazard in seismic design engineering but also rock mechanical properties. This study uses the method of H/V spectral ratio of observed ground motion between target site and reference site called a reference site method. In addition to using the vertical Fourier spectrum of the reference site, we try out the horizontal Fourier spectrum as a new method in this study. We analyze H/V spectral ratio of six ground motions respectively, observed at four sites close to Yedang Reservoir. We then compare site amplification effects at each site using 3 kinds of seismic energies including S waves, Coda waves energy, and background noise. The results suggest that each site showed similar site amplification patterns in S waves and Coda waves energy. However, the site amplification of background noise shows much different characteristics from those of S waves and Coda wave energy, which suggests that the background noises at each site have their own developing mechanism. Each station shows its own characteristics of specific resonance frequency and site amplification properties in low, high and specific resonance frequency ranges. Comparison of the method used in this study to the others that used different methods can provide us with more information about the dynamic amplification of a site characteristics and site classification.

• Journal of KIISE:Databases
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• v.31 no.4
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• pp.395-408
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• 2004

A conjunctive Boolean text query refers to a query that searches for tort documents containing all of the specified keywords, and is the most frequently used query form in information retrieval systems. Typically, the query specifies a long list of keywords for better precision, and in this case, the order of keyword processing has a significant impact on the query speed. Currently known approaches to this ordering are based on heuristics and, therefore, cannot guarantee an optimal ordering. We can use a systematic approach by leveraging a database query processing algorithm like the dynamic programming, but it is not suitable for a text query with a typically long list of keywords because of the algorithm's exponential run-time (Ο(n2$^{n-1}$)) for n keywords. Considering these problems, we propose a new approach based on a property called the join sequence separability. This property states that the optimal join sequence is separable into two subsequences of different join methods under a certain condition on the joined relations, and this property enables us to find a globally optimal join sequence in Ο(n2$^{n-1}$). In this paper we describe the property formally, present an optimization algorithm based on the property, prove that the algorithm finds an optimal join sequence, and validate our approach through simulation using an analytic cost model. Comparison with the heuristic text query optimization approaches shows a maximum of 100 times faster query processing, and comparison with the dynamic programming approach shows exponentially faster query optimization (e.g., 600 times for a 10-keyword query).

• Korean Institute of Interior Design Journal
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• no.40
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• pp.34-41
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• 2003

A purpose of this study is to comprehend a concept of 'Open Space', realization of a deconstruction, presented in his works, based on a deconstruction and surrealism Coop Himmelblau's philosophical contemplation and to look into how this concept is interpreted in spaces. A concept of 'Open Space' is functioned as not a singular meaning but a multiple meaning accompanied with other formative ingredient and contemplation, scientific paradigm and a realation with a surroundings. The concept of 'Open Space' in their architentural space is applied. First, the space openness that represents to the extreme a concept 'Open Space', as a 3D designing ways that demolishes a structure and outgrows an ex siting thinking pattern, represents multiple grade spaces and an anti-gravity space. In a material, using glass and iron provides a spacial transparency and through this, visibly liberal sense that an interior and exterior is felt as an unification. Second, an non-expressive box pattern repulses to a spatial rank nature, outgrowing an uniform geometrical system, through demolishing a geometrical system, an edge and fold pattern. This is, as an anti-gravity, dynamic a typical structure, outgrowing an orthogonal system, interpreted as a composite meaning without division in spatial area. Third, the collage is used to represent a complexity and pluralism in representing 'Open space'. The collage that forms a image through combining a fragmentary elements into being a space change, composite constitution and spatial amusement. Thus, It is worthwhile to study how the collage that forms a diverse shape will be developed making what impact as an age and surroundings changed. As we contemplate in former part, Coop Himmelblou has deployed 'deconstruction beyond deconstruction' realm as just their midterm concept in their works like the words 'The architecture must climb', the deconstructive architect. A studying for their works reflecting the 'Open Space' concept based on deconstruction must be lasted and this enables us to comprehend space concept containing an architecture and interior design.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.4
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• pp.227-234
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• 2005

In this paper, a smart wireless MEMS-based accelerometer(MA) system has been designed and experimented for smart monitoring system of civil structures. Various performance and experimental tests have been carried out to evaluate whether this system is suitable for monitoring system of civil structures. First, we examined its sensitivity, resolution, and noise, specifically to evaluate the performance of the smart wireless MA system. The results of experiments enabled us to estimate performance of the MA in SWMAS in comparison to the value of data sheet from MA. Second, characteristics of model structure were analyzed by the ambient vibration test based on the NExT combined with ERA. Finally, this analysis was compared to the one that was made by FE results, and the comparison proved that a smart wireless MA system was fitted in smart monitoring system effectively.

• Journal of Science of Art and Design
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• v.1
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• pp.267-303
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• 1999

The visual humor can be regarded as an original source for creative ideation. There are several types of humor. for example,'wit, satire, irony and so on. These can be motivations of developing an up-to-date idea. Wit differs from most humor in being purely intellectual, rather than relying on incongruities that come up naturally in many situations. The humor of words contains pun, hyperbole, repetition, and comparison or contrast. Especially in case of pun, it can be most important type of humor for making analytical and humorous effects visually. Pun, meaning the humor of double meaning, furnish us with much of our humor. The concept of pun is the most valuable for creating the visual humor by substituting, combining and manipulating symbols. There are essentially three distinct categories of puns : the literal pun, the suggestive pun, and the comparative pun. All types of puns belong to one of these three groups. The definitions are simple to understand and easy to apply for creating the visual humor, In order to develop a better conceptual model, (this researcher) reexamine the concept of humor, the relationship of humor to various types of message processing, and the relationship of humor to various aspects of message. This thesis. is primarily concerned with basic theories of humor such as concepts of humor, types of humor and analysis of humor. And this contains the research of humor's communications effects and theory of humor response with literature reviews. Modem theories of humor response generally fall into three major schools : Incongruity theories, Superiority theories and Arousal (Relief theories. Together these three approaches address the cognitive-perceptual, affective-evaluative and psycho-dynamic dimensions of a subject's humor response. The literature research of humor and humor response theory in communications and visual communications can help the visual application of humor concepts and usefulness of visual humor appeals. This research agreed that the humor and visual humor must be very effective at being as a means for the advertising expression, not for the purpose itself. In addition, this research is aimed at studying significations and usefulness of visual humor through semiotic approaches in the near future. Then it can be essencial research for the appropriate situational uses of humor related to media, product, and audience factors, such as nationality, age, standard of living, sexuality, and so on.