• Journal of Korean Ophthalmic Optics Society
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• v.15 no.4
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• pp.381-388
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• 2010

Purpose: This study was to compare the contrast sensitivity evaluated the visual ability at near wearing functional lenses for pre-presbyopes altered their single vision lenses to functional progressive addition lenses with low addition for 2 months. Methods: Healthy 32 subjects aged 24.03${\pm}$1.87 (male 23, female 9) who were recruited from university students wore functional progressive addition lenses(EYE-T, Chemilens Co., Korea, ADD 0.75D) for 2 months. Corrected visual acuity at distance and near and contrast sensitivity at near were tested right after wearing functional progressive addition lenses to compare wearing single vision lenses. And we had second test after 2 months later. Results: Comparing between test and retest, contrast sensitivity at near wearing functional progressive addition lenses was improved more than wearing single vision lenses at all spatial frequency of right, left and both eyes. Conclusions: There was considered that contrast sensitivity test is useful to evaluate the visual ability as well as quality of near work and can be applied variously.

• Korean Journal of Plant Taxonomy
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• v.45 no.3
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• pp.213-220
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• 2015

To elucidate the origin and patterns of establishment of insular plants on Ulleungdo Island, maternally inherited chloroplast DNA, which is useful for tracing seed movements, was used. Fagus multinervis, an endemic species that dominated broadleaf deciduous forests on Ulleungdo Island, is an excellent model for such a study. To understand the diversity and spatial distribution of the chloroplast haplotypes of F. multinervis, nucleotide sequences of the psbA-trnH region were determined from 144 individuals sampled throughout the island. Results of a phylogenetic analysis of the region with close relatives of F. multinervis suggest that F. multinervis is sister to a clade of F. japonica and F. engleriana. No haplotype variation was found within F. multinervis. This remarkably low cpDNA haplotype diversity is in contrast to the findings of previous allozyme studies of F. multinervis populations that showed high genetic diversity on Ulleungdo Island. Repeated colonization during the early stage of establishment via birds that migrated from a source area where the F. multinervis cpDNA haplotype was geographically structured may have resulted in the observed pattern of haplotype diversity. Alternatively, long-distance dispersal of seeds of the progenitor of F. multinervis via birds or typhoons to Ulleungdo may have been a single event, whereas the immigration of pollen from the mainland likely occurred frequently. Comparative phylogeographic studies of other species endemic to Ulleungdo Island and their close relatives on the neighboring mainland are necessary for a more complete understanding of the evolution of the island's native species.

• Journal of Korean Society of Transportation
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• v.31 no.4
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• pp.47-57
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• 2013

This study aims at analyzing transportation equity between geographical areas of Gyonggi Province, by taking both the transportation infrastructure and travel behavior into account. Indicators of transportation infrastructure include the indices of road infrastructure, transit infrastructure and regional characteristics. Travel behavior concerns information from bus card data on a survey day. The hot-spot analysis conducted included spatial cluster analysis and global/local regression analyses. The analysis results identified geographical areas of four different classes of transportation equity, from the area with high level infrastructure surrounded by the areas with high level infrastructure (HH) to the area with low level surrounded by the areas with low level (LL). The area of HH type showed big numbers of passengers, trips and transfers, whereas the area of LL type shows big figures of internal trip frequency, travel time, travel distance, travel speed and transit fare. Global regression analysis showed that number of passengers, number of transfers, number of internal trips and mean travel speed are important to the level of transportation infrastructure. GWR with these four significant variables significantly improved the AICs and ANOVA results, which implies that the infrastructure is likely explained by travel characteristics differently between geographical areas in Gyonggi Province.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.1
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• pp.59-77
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• 2003

This study is to validate the use of macro language for the land suitability analysis aiming to help to resolve land use conflicts. The silver-town suitability analysis is conducted on the Geejang Gun, Busan Metropolitan city. Such digital maps as terrain, road, facility, and water body were created for various cartographic models. A cartographic model identified the best suitable areas for silver-town development based on the such site selection variables as a distance to facility and road, slope and aspect of terrain, land use etc. Then, the other cartographic model identified the most favorable site among the candidate sites based on the comparison of the aspect of proximity, usage and environmental quality. Macro language was used for these modeling process and was used for the manipulation of all these spatial variables used in the models to resolve land use conflicts relating to the decision making process of the final site selection. This study will improve the effectiveness and rationality of the traditional site suitability analysis.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.1
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• pp.53-63
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• 2016

In this paper, we proposed the improvements for performance test and surveying equipment regulations, standards, methods and procedures, depending on the need of improving the legal system for surveying equipment in a diverse and sophisticated surveying industry. This research was performed first investigating the existing legal systems(Act on the establishment and management of spatial data, Framework act on national standards, ISO 17123, JIS B 7912) with respect to the surveying equipment performance testing and the research for IOS and KOLAS suggested the improvements on the application for the surveying equipment performance testing standard. More exactly, first, two years were presented for the surveying equipment performance testing cycle considering the precise accuracy of the instrument stability, purpose and frequency of use, etc. Second, the abolition of the measurement distance by grade and the upward or cross-grade adjustment of the single prism standards about the light wave rangefinder and total station were suggested for the improvement on survey equipment performance criteria. Third, since the main function of total station is focused on a three-dimensional coordinate measurement due to the improvement of surveying equipment performance testing, it was proposed to use the precision(repeatability) of the coordinate measuring method as an evaluation method.

• Progress in Medical Physics
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• v.9 no.1
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• pp.1-9
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• 1998

In order to provide complementary image data, CT(computed tomography), MR(magnetic resonance) and angiography have been used in the field of Stereotactic Radiosurgery(SRS) and neurosurgery. The aim of this work is to develop 3-D stereotactic localization system in order to determine the precise shape, size and location of the lesion in the brain in the field of Stereotactic Radiosurgery(SRS) and neurosurgery using multi-image modality and multi purpose QA phantom. In order to obtain accurate position of a target, Hitchcoke stereotactic frame and CT/angiography localizers were rigidly attached to the phantom with nine targets dispersed in 3-D space. The algorithms to obtain a 3-D stereotactic coordinates of the target have been developed using the images of the geometrical phantom which were taken by CT/angiography. Positions of targets computed by our algorithms were compared to the absolute position assigned in the phantom. Outlines of targets on each CT image were superimposed each other on angiography images. A spatial mean distance errors were 1.02${\pm}$0.17mm for CT with a 512${\times}$512 matrix and 2mm slice thickness, 0.41${\pm}$0.05mm for angiogra- phy localization. The resulting accuracy in the target localization suggests that the developed system has enough Qualification for Stereotactic Radiosurgery (SRS).

• Journal of the Korean Society of Radiology
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• v.11 no.4
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• pp.221-225
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• 2017

To evaluate the performance of ultrasound imaging system, we investigated the change of spatial resolution according to changing sonic velocity change parameter provided by ultrasound equipment. Ultrasound phantom images were obtained using a 3.0 ~ 5.0 MHz convex transducer in an ultrasound diagnostic device used at a medical institution located at Iksan. N-365 multi-purpose ultrasound phantom was used to measure longitudinal distance measurement accuracy and longitudinal and transverse resolution. In the same manner, the sonic velocity of the ultrasound equipment was changed from 1580 m/sec to 1400 m/sec in six steps, and the full width at half maximum(FWHM) was measured using the image J program to determine whether the measured values were different. As a result, lateral resolution was measured from 1.91 mm to 5.3 mm according to the speed change, and the smallest FWHM was 1.91 mm at 1420 m/sec. The axial resolution was measured from 1.03 mm to 1.14 mm according to the speed change, and the smallest FWHM was 1.03 mm at 1400 m/sec. The slower the sound velocity of the ultrasound equipment, the shorter the length of longitudinal measurement.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.415-417
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• 2002

Images of microcalcification specks showed large variation in conventional radiographs of phantoms which are approved for mammography image quality standard by the American College of Radiology (ACR). This kind of variation is not appropriate for image quality standards because the number of specks are visually counted in images and that number is important in image quality evaluation. Our study using synchrotron radiation (SR) imaging revealed the overlapping of micro-sized air bubble(s) to some specks, and also the structural deformation or crackings. Eight phantoms approved by ACR from two different makers and an air-bubble phantom were examined. SR imaging was performed at a synchrotron radiation facility, SPring-8, in Japan. The image-detector was a fluorescent-screen optical-lens coupling system using a CCD camera with a spatial resolution of 6 $\square$m. Objects when imaged with longer sample-to-detector distance show edge enhancement due to a difference in refraction indices, that is refraction enhancement. Refraction-enhanced SR images revealed that some of specks carried foreign objects, which were proven to be air. In phantoms provided by one maker, attaching/overlapping airs were observed for 62 out of 150 specks (41%) , with a higher incidence for the smallest specks. A speck becomes hardly visible in a conventional radiograph when air(s) overlaps the majority part of a speck, though depending on the size of the air-inclusion and on its configuration. Those airs might have been adsorbed on a speck surface before being embedded and then introduced into the matrix together with specks. Our study using SR imaging has clearly shown the nature of defects in some mammography phantoms which seriously degrade the quality as an image standard.

• Korean Journal of Cognitive Science
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• v.24 no.4
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• pp.365-391
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• 2013

Negative repetition effect (NRE) refers to the phenomenon that the accuracy of report is impaired when a target was flanked by the same distractor than when by alternative distractor. To probe the nature of NRE, this study introduced attention window(s) indicating the positions where a target might be presented, and non-attention window(s) where a target could not be presented. Attention windows are supposed to help participants detect targets readily. Two among three positions are indicated by attention windows in Exp. 1, and a single large attention window encompassing central two positions among four positions was used in Exp. 2, and either large or small attention window was used depending on the number of target candidates in Exp. 3. In the result of three experiments, NREs were consistently observed when both positions of a target and a distractor were indicated by previous attention windows. However, NREs (including its tendency) and its opposite, PREs were observed when a distractor was presented in the non-attention position, depending on its distance from the target and the size of attention window. It seems that this pattern of repetition effects is hard to be explained by repetition blindness hypothesis (Kanwisher, 1991), positional uncertainty hypothesis (Keren & Boer, 1985), and inhibitory attention capture hypothesis (Kwak et al., 1993). Instead it was proposed that shifting of spatial attention should be considered accordingly with the structure of stimulus display. The promising role of this task was discussed in studying the relation of attention and perception.

• Journal of Cadastre & Land InformatiX
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• v.47 no.2
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• pp.91-105
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• 2017

It is important to identify new apartment buyers with the object of investment and owner-occupation because it may determine the scope of marketing and marketing strategies. Establishing an more effective marketing scope and strategies should result in maximizing profits and reducing expenses. In this study, we split the participants in the new apartment market depending on the buyers' intent - investment and owner-occupation - and then examine their characteristics. We employ condominium buyers' information from 2011 to 2016, which is provided by the one of the largest construction companies in South Korea. The sites of the condominium samples locate in Gyeongnam and Busan areas and the number of household sample is 5,549. The results show that investors are approaching at a greater distance than actual buyers. The higher the age and the lower the price, the higher the probability of participation of investors. We also find that the samples of Busan have different results from the others, which may imply that the area has more demand due to its attractiveness.