• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.2
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• pp.18-29
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• 2022

The purpose of this study is to examine the spatial characteristics and factors in the occurrence of COVID-19 from January 20 to August 30 of 2020. The exploratory spatial data analysis and spatial econometrics model are used. The spatial unit of analysis is 255 si-gun-gu in Korea. As a result of the analysis, COVID-19 infection did not appear to be a significant factors(host and environment) influencing the emergence of existing new infectious diseases, but there was a relationship between spatially adjacent areas and their occurrence. It also showed a close relationship with the outbreak pattern of group 4 infectious diseases, another type of new infectious disease in Korea. The result of this study shows that COVID-19 is not a new pattern of emerging infectious diseases. It means that the properties of the space where new infectious diseases appear must be continuously managed in order to effectively control new infectious diseases.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.7
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• pp.648-656
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• 2009

We perform an analysis of the characteristics of the time-reversal pulse in Rayleigh or Ricean fading channel environments. We verify it by using Monte Carlo simulation. In a time-reversal system, each antenna in the time-reversal array receives signals from the transmitter and reverse the received signal in the time axis and then resend it to the original transmitter. We assume that the channel characteristics varies very slowly and the spatial separation between the antennas is not large. Hence the signals received by each antenna are correlated. In this paper, the effect of the correlation on the time-reversed pulse is examined, which includes the spatial properties of the time-reversal pulse such as the focus size, and spatial power distribution.

• Korean Institute of Interior Design Journal
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• v.25 no.6
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• pp.3-14
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• 2016

According to Plato's ontology, we lead our lives by establishing a relationship with others in the society. However in rapidly changing era, our lives was gradually moving towards personal tendency. Even for the relationship with family, not with others. Thus, awareness about owning properties has changed due to the sociocultural factors and increase number of single-person households. So in this study, the considerations for single-person housing were perceived through preceding research, and the elements making spatial boundary of shared housing were drawn to make rational space sharing based on the boundary with others and of the living environment. With overall analysis based on the spatial boundary features of planned shared housing, the plan characteristics according to the spatial boundary of the current shared housing is to be drawn and analyzed. Third, The expressive and structural features of spatial boundary as above appear with mutual flexible connectivity, And the result shows that the modularity was the highest. Among them variable coupling modularity of shows how it is possible to combine efficiently and variously the private and public spaces with regularity of 'space of optimal unit'. This study drew plan characteristics from more detailed space border of shared housing. Therefore, The basic framework of the characteristics spin for the cases that newly emerge later on.

• Korean Institute of Interior Design Journal
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• v.24 no.6
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• pp.96-106
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• 2015

Occupying the center of architecture, design, painting and culture, minimalism is aesthetics of essence that reflects modern age but transcends age at the same time. Pursuing minimalist trend like this and covering the range of furniture, interior and architecture, total designer Antonio Citterio is developing minimalist designs of his own. Called one of the 3 greatest furniture designers in the world today, he leads the trend and enjoys high reputation as a world-renowned interior designer and architect. Therefore, the purpose of this study is to analyze and integrate minimalist descriptive characteristics which appeared in interior space of Citterio who pursues minimalist design. As a study method, this study reorganized minimalism from methodological perspective, drew out expressive characteristics of minimalist interior spaces unique to Citterio based on background and influence of Citterio's design and, centering on this frame of analysis, analyzed and integrated interior spaces he designed. The results of this study are as follows; first, in order to overcome problems that can become monotonous in a minimalist space, Citterio provides spatial experiences to feel visual and spatial variations using the ramp and bridge. Second, he created various senses of space with visual and spatial expansion using transparency in the walls made of glass. Third, with linear expressions, he designed modern spaces with beauty of proportion and balance through contrast and emphasis. Fourth, he made constructive expression through exposure of structures or stairs in the space. Fifth, he created sophisticated atmosphere with contrast between natural and artificial materials and emphasis of material properties. Sixth, his design also shows the characteristic of using furniture as the role of adjusting overall atmosphere of interior space, not as separated parts from it. The author hopes that above results of this study will provide new implications for the development of domestic interior design.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.9
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• pp.999-1004
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• 2014

In the present paper, the effects of initial crack location on spatial randomness of fatigue crack growth resistance (FCGR) in friction stir welded (FSWed) AA7075-T651 plates were studied. The objective of this study is to characterize the statistical properties of FCGR for three different types of initial crack location (ICL) specimens. In this work, the FCGR coefficients were treated as a spatial random process. It was found that the FCGR coefficients for all initial crack location specimens closely followed a two parameter Weibull distribution. The shape parameter of the Weibull distribution for BM-ICL specimens showed the largest value of 7.50, and that for the WM-ICL specimens showed the smallest value of 2.61. In addition, the autocorrelation functions for all the ICL specimens followed the exponential function.

• Journal of Energy Engineering
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• v.22 no.2
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• pp.156-168
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• 2013

Drilling expedition #1 in 2007 and drilling expedition #2 in 2010 were performed for gas hydrate resources evaluation and optimal site selection of pilot test in Ulleung basin, East Sea, Korea. This study presents to build the 3D spatial distribution models using the estimated sedimentary facies, porosity, and gas hydrate saturation derived by well logs and core analysis data from UBGH1-4, UBGH1-9, UBGH1-10, UBGH1-14, UBGH2-2-1, UBGH2-2-2, UBGH2-6, UBGH2-9, UBGH2-10 and UBGH2-11. The objective of 3D spatial distribution modeling is to build a geological representation of the gas hydrate-bearing sediment that honors the heterogeneity in 3D grid scale. The facies modeling is populating sedimentary facies into a geological grid using sequential indicator simulation. The porosity and gas hydrate saturation modeling used sequential Gaussian simulation to populate properties stochastically into grid cells.

• Environmental and Resource Economics Review
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• v.14 no.4
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• pp.923-941
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• 2005

Odor problem of livestock operation is important issue in a local community. I quantified the property price impact of 199 livestock operations for 3,355 housing sales in the U.S (Colorado). Spatial hedonic model was adopted to deal with spatial autocorrelation in housing market. Small beef and dairy operations, which are the traditional agricultural sector, seem to create a positive rural lifestyle amenity effect. However, the impact of livestock operation on rural residential sales turns to negative if the operation is over a certain size and species. Large hog and sheep operation seems to bring fatal economic loss from the local community perspective if it close to residential area. Livestock odor is one of the negative externality, the results provide the potential social cost of the livestock sector in the region. Policy makers may incorporate this social cost in the regional planning to minimize the social and maximize the development effect. Therefore, local officials and private individuals should carefully consider the location and characteristics of new residential properties and livestock operations alike.

• Spatial Information Research
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• v.21 no.1
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• pp.75-86
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• 2013

The use of planning support systems in urban planning and management provides objective information that is beneficial in the decision-making stage. The existing planning support system, however, lacks in the consideration of ecological properties. In this study, a planning support system development that is capable of reflecting ecological elements was set as the ultimate goal. This system can support planning processes ranging from ecological potential anaylsis to alternatives designing and stimulation. Additionally, factors such as soil, water, climate, biotope, ecological network and recreation can be handled according to their natural potentials. The establishment and visualization of land use planning that addresses ecological characteristics based on the analyzed results are possible. Therefore, this system could operate as a framework to assist planners and decision makers through a computer-based system to provide useful ecological information and to allow effective decision-making by analyzing, displaying and visualizing ecological spatial data.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.4 s.334
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• pp.15-20
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• 2005

Multi-Input, Multi-Output system suffers for the spatial channel correlation due to lack of spatial diversity. To overcome this defect, the antenna selection and switching system is proposed which selects the adequate antenna subset with highest channel diversity gain and switches the trasmission techniques according to channel environments. However. its performance analysis is insufficient due to the difficulty of modeling the spatial channel correlation. In this paper, the theoretical upper bound of symbol error probability is derived by using the statistical properties of Frobenius norm and minimum eigen-value of channel matrix. By computer simulation, it is shown that the derived theoretical upper bound is similar to the simulation results.

• Korean Journal of Digital Imaging in Medicine
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• v.10 no.2
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• pp.23-31
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• 2008

Computed radiography(CR) has been widely used in the field of diagnostic radiography since digital X-ray image was introduced. The imaging performance of CR system was studied by analyzing the digital image data of the CR images which are the outcomes of the whole imaging system composed of image plate(IP), laser digitizer, analoge-digital convertor, and a given image processing unit. In this study, we used a conventional CR system made by Agfa. From the flat field image of 150$\times$150 image pixels, signal-to-noise ratio(SNR) was calculated. SNR of the CR image increases in proportion to logarithm value of the X-ray exposure irradiated on the IP. SNR is less than about 6 at the exposure below 0.2mR and is more than 10 at the exposure above 0.54mR. In our study, most of images obtained by the smaller exposures less than 2.0mR can not be readable. In general, the minimum value of the SNR ranges from 3 to 5. We obtained modulation transfer function(MTF) by analyzing the bar pattern image which was made under conditions as follows: X-ray tube potential was 55kVp, the IP exposure was 0.54 mR, and the distance between X-ray source to IP was 2m, where bar pattern was located on the IP. MTF is 23% at 2.5lp/mm spatial frequency. Provided that the MTF of noise equivalent modulation is 10%, the CR system has the limiting spatial resolution of 3.2lp/mm. If the image sharpness is evaluated by the spatial frequency where MTF is 50%. the corresponding spatial frequency is 0.5$\sim$0.75lp/mm. MTFA(Modulation Transfer Function Area) is 1.0lp/mm. Compared with the Fuji CR whose MTFA is 1.1lp/mm, Agfa CR in this study shows almost same MTFA performance.