• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.1
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• pp.113-119
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• 2006

It is now established that more than two types of blended aggregate have beneficial effects on quality and supply of concrete in the long run. However, studies on blended aggregate have not widely been progressive and the evaluation method of its most favorable mixture proportion is still needed. Therefore this study investigated the most favorable mixture proportion through the physical experiment of fresh and hardened state's cement mortar, in response to three types of composite ratio, natural fine aggregate(Ns), crushed fine aggregate(Cs) and recycled fine aggregate(Rs). Test showed that increase of blending ratio of Ns and Cs improved fluidity of mot1ar. For the properties of compressive and flexural strength, mortar blending Ns and Cs properly, exhibited similar value to one using only Cs, while mortar mixing Rs showed lower strength value as less as 6% of control one. Mortar using only Rs exhibited the largest drying shrinkage value. In addition, even thought it is not a clear quantitative analysis, technical-imaging-skill presenting the most favorable mixture proportion 3-dimensionally is proposed in this research, in order to notify the proportion easily.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.54.1-54.1
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• 2016

Multi-wavelength variability is a staple of active galactic nuclei (AGN). Optical variability probes the nature of the central engine of AGN at smaller linear scales than conventional imaging and spectroscopic techniques. Previous studies have shown that optical variability is more prevalent at longer timescales and at shorter wavelengths. Intra-night variability can be explained through the damped random walk model but small samples and inhomogeneous data have made constraining this model hard. To understand the properties and physical mechanism of intra-night optical variability, we are performing the KMTNet Active Nuclei Variability Survey (KANVaS). Using KMTNet, we aim to study the intra-night variability of ~1000 AGN at a magnitude depth of ~19mag in R band over a total area of ${\sim}24deg^2$ on the sky. Test data in the COSMOS, XMM-LSS, and S82-2 fields was obtained over 4, 6, and 8 nights respectively during 2015, in B, V, R, and I bands. Each night was composed of 5-13 epoch with ~30 min cadence and 80-120 sec exposure times. As a pilot study, we analyzed data in the COSMOS field where we reach a magnitude depth of ~19.5 in R band (at S/N~100) with seeing varying between 1.5-2.0 arcsec. We used the Chandra-COSMOS catalog to identify 166 AGNs among 549 AGNs at B<23. We performed differential photometry between the selected AGN and nearby stars, achieving photometric uncertainty ~0.01mag. We employ various standard time-series analysis tools to identify variable AGN, including the chi-square test. Preliminarily results indicate that intra-night variability is found for ~17%, 17%, 8% and 7% of all X-ray selected AGN in the B, V, R, and I band, respectively. The majority of the identified variable AGN are classified as Type 1 AGN, with only a handful of Type 2 AGN showing evidence for variability. The work done so far confirms there are more variable AGN at shorter wavelengths and that intra-night variability most likely originates in the accretion disk of these objects. We will briefly discuss the quality of the data, challenges we encountered, solutions we employed for this work, and our updated future plans.

• Investigative Magnetic Resonance Imaging
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• v.2 no.1
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• pp.83-88
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• 1998

Purpose : Authors correlated the three-dimensional time-of-flight MRA signal intensity characteristics and flow profile simulated by computer in an experimental flow phantom model. Materials and Methods : The three-dimensional time-of-flight MRA was performed in a fusiform flow phantom and analyzed the flow signal. computer assisted flow simulation was performed in same flow geometry. The MRA signal intensity and flow velocity distribution and direction was compared. Results : The flow was depicted as homogeneous signal internsity in inlet and outlet area and inhomogeneous signal intensity in fusiform area. Typically, the flow was depicted as target appearance in transition area to outlet. Whereas mean signal internsity decreased slowly in fusiform area, it rapidly dropped and resumed in transition area to outlet. In computer assisted flow simulation, Whereas there were flow velocity decrease and flow direction change to peripheral in entrance to fusiform area, ther were rapid flow velocity resuming and flow direction change to central in transition area to outlet. Conclusion : The signal loss and target appearance in transition area to outlet is characteristic of fusiform flow. These signal changes correlate with abrupt flow velocity and direction change well.

• The Journal of Natural Sciences
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• v.14 no.1
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• pp.123-138
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• 2004

This study was to investigate the planting arrangement of ornamental trees and shrubs that leads to an appropriate, type of templescape. Temples sampled for this study were Woljonsa, Sineunsa, Sinreugsa and Mitasa which fall all under the category of the level land. The results obtained were as follows : Open space of Daewoongjeon in all temples, a main Sanctuary among temple buildings, where Buddha is enshrined in, we could not find any kinds of trees/shrubs to be planted. But tere were Acer mono, Acer planmatum, Crataegus pinnatifidam Raododendron poukhanense, Texus cuspidata and Buxus mincrophylla to be planted, before Jeokkwangjeon, in which Buddha is exceptionally enshrined. In Geugragjeon of both temples of Sinheunsa and Sinreugsa, and Elysium building and Muryangsujeon of Woljeongsa temple, an immeasurable bliss building, in which an Amitabha is enshrined. was Taxus cuspidata planted numerously found. Particularly, Josadang, Muryangsujeon and Samsungkag of Woljeongsa temple commonly had Sciadopiys verticillata, which is known as one of Japanese-favorite trees. Syinga oblata Lindaley was also observed at Jeokkwangjeon of Woljeongsa temple and Keungnakjon of Sinheungsa temple, and Vidurnun opulus var. calvesvens, a symbolic flower tree imaging Buddha's head, was planted in Myungboojeon of Sinheungsa temple and Keugnakjeon of Sinreugsa temple. Juniperus chinensis which could be observed in both temples Sinheunsa and Sinreugsa was well arranged enough to be easily captured by human's eyes. In terms of templescape that might be considered in templescape, the correlation between trees/shrubs and temple buildings was thoroughly discussed. And, with the results obtained through precise studies, we presented here in this paper newly designed model of templescape in level land buddhist temples which is possibly applied for planting and arrangement of trees or/and shrubs.

• Journal of Radiation Protection and Research
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• v.36 no.3
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• pp.140-147
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• 2011

Our purpose is to specify behavior and environmental factors aimed at reducing the exposed dosage caused by PET-CT and to develop radiation safety management guidelines adequate for domestic circumstances. We have used a multistep-multimethod as the methodological approach to design and to carry out the research both in quality and quantity, including an analysis on previous studies, professional consultations and a survey. The survey includes responses from 139 practitioners in charged of 109 PET-CTs installed throughout Korea(reported by the Korean Society of Nuclear Medicine, 2010). The research use 156 questions using Cronbach's ${\alpha}$ (alpha) coefficients which were: 0.818 for "the necessity of setting and installing the radiation protective environment"; 0.916 for "the necessity of radiation protection", "setting and installing the radiation protective environment"; and 0.885 for "radiation protection". The check list, derived from the radiation safety management guidelines focused on behavior and environment, was composed of 20 items for the radiation protective environment: including 5 items for the patient; 4 items for the guardian; 3 items for the radiologist; and 8 items applied to everyone involved; for a total of 26 items for the radiation protective behavior including: 12 items for the patient; 1 item for the guardian, 7 items for the radiologist; and 6 items applied to everyone involved. The specific check list is shown in(Table 5-6). Since our country has no safety management guidelines of its own to reduce the exposed dosage caused by PET-CTs, we believe the guidelines developed through this study means great deal to the field as it is not only appropriate for domestic circumstances, but also contains specific check lists for each target who may be exposed to radiation in regards to behavior and environment.

• The Journal of the Korean dental association
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• v.53 no.4
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• pp.266-274
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• 2015

The price for health service are decided by very complicated process because many of factors are related with them. The RBRVS(resource-based relative value scale) were used to calculate the Korean health service fees including dental fees. This study aimed to compare dental fees of Korea with other countries, such as Japan, Germany, and the US for evaluating the adequacy. Dental fees were categorized as oral evaluation and imaging, dental treatment including restorative, periodontal, and surgical work, and preventive treatment and compared by each country. The official documents about dental fees were collected from Korea, Japan, Germany, and the US. Each fee was presented as their own currency at first. Then they were converted into Korean won (KRW) by applying the market exchange rates at a specific point of time. Finally the fees were adjusted by purchasing power parities (PPPs) which equalize the different currencies. In general, the level of Korean fees were markedly low compared to those of Japan, Germany, and the US. German fees were similar or higher than that of Japan, and the US. The Korean fees were lower than three other countries 1.2~4.1 times for oral evaluation and 2.2~7.3 times lower for panoramic radiography. The endodontic fees of Japan, Germany, and the US were higher 1.8~15.3 times and 4.0~35.9 times for the deciduous teeth extraction compared to the Korean. In Japan the prophylaxis was 3.2 times more priced than the Korean fee. Exceptionally, the fees for re-evaluation, amalgam filling, and scaling were lower priced in Japan than other countries. This study has limitations on the items in definition and contents of dental practices units which were not exactly comparable and differently determined by countries. However, this study is meaningful because it surveyed the price levels to compare four different countries and then applied PPPs adjustment. This finding can be used to develop the dental RBRVs of Korean national health insurance and will contribute to improving the payment systems of health care.

• The Korean Journal of Nuclear Medicine
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• v.37 no.4
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• pp.229-234
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• 2003

Purpose: Since the prognosis of measles encephalitis is poor, early diagnosis and proper management are very important to improve clinical outcomes. We compared Tc-99m ECD brain SPECT (SPECT) with MR imaging (MRI) for the detection of acute measles encephalitis. Materials and Methods: Eleven patients(M : F=4 : 7, age range 18 months-14 yrs) with acute measles encephalitis were enrolled in this studies. All of them underwent both MRI and SPECT. The results of SPECT were scored from 0 (normal) to 3 (most severe defect) according to perfusion state. We compared two image modalities for the detection of brain abnormality in acute measles encephalitis. Results: Seven of 11 patients (63.6%) revealed high signal intensity in the white matter on T2WI of MRI, on the other hand all patients (100%) showed hypoperfusion on SPECT. Severe perfusion deficits above score 2 were located with decreasing frequencies in the frontal lobe (81.8%), temporal lobe (72.7%), occipital lobe (27.3%), basal ganglia (27.3%), and parietal lobe (9.1%). Conclusion: We conclude that SPECT is more useful than MRI for the detection of brain involvement in patients with acute measles encephalitis.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.3
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• pp.311-319
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• 2018

Mitochondrial calcium overload is a crucial event in determining the fate of neuronal cell survival and death, implicated in pathogenesis of neurodegenerative diseases. One of the driving forces of calcium influx into mitochondria is mitochondria membrane potential (${\Delta}{\psi}_m$). Therefore, pharmacological manipulation of ${\Delta}{\psi}_m$ can be a promising strategy to prevent neuronal cell death against brain insults. Based on these issues, we investigated here whether nobiletin, a Citrus polymethoxylated flavone, prevents neurotoxic neuronal calcium overload and cell death via regulating basal ${\Delta}{\psi}_m$ against neuronal insult in primary cortical neurons and pure brain mitochondria isolated from rat cortices. Results demonstrated that nobiletin treatment significantly increased cell viability against glutamate toxicity ($100{\mu}M$, 20 min) in primary cortical neurons. Real-time imaging-based fluorometry data reveal that nobiletin evokes partial mitochondrial depolarization in these neurons. Nobiletin markedly attenuated mitochondrial calcium overload and reactive oxygen species (ROS) generation in glutamate ($100{\mu}M$)-stimulated cortical neurons and isolated pure mitochondria exposed to high concentration of $Ca^{2+}$ ($5{\mu}M$). Nobiletin-induced partial mitochondrial depolarization in intact neurons was confirmed in isolated brain mitochondria using a fluorescence microplate reader. Nobiletin effects on basal ${\Delta}{\psi}_m$ were completely abolished in $K^+-free$ medium on pure isolated mitochondria. Taken together, results demonstrate that $K^+$ influx into mitochondria is critically involved in partial mitochondrial depolarization-related neuroprotective effect of nobiletin. Nobiletin-induced mitochondrial $K^+$ influx is probably mediated, at least in part, by activation of mitochondrial $K^+$ channels. However, further detailed studies should be conducted to determine exact molecular targets of nobiletin in mitochondria.

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.1
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• pp.61-68
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• 2016

Digital aerial images have been commonly used in a large scale map production owing to their excellent geometry, and high spatial and radiometric resolution in recent years. However, a quality verification process for acquired images should be preceded in order to secure the high precision and reliability of produced results. Several experimental studies to verify digital imaging systems have been vigorously researched by constructing permanent test field in abroad. On the other hand, it is urgently necessary to suggest a practical scheme for an image quality verification, because this related study and experiment are still in its early stage at home. Hence, this study aims to present an easy method to measure the spatial resolution of the image in a visual way using a portable Siemens star. The images used in the study were obtained with three different cameras, two frame array sensors of DMC, UltraCamXp and a linear array sensor of ADS80. The Siemens star target appeared in every image is extracted and then the spatial resolution of image is compared with theoretical GSD(Ground Sample Distance) by a visual method. In addition, the change of spatial resolution depending on the location of the Siemens star from image center and flight direction and cross-flight direction is also compared and analyzed. As study results, while the theoretical GSDs of images taken with each camera are about 6~9cm, the visual resolutions are 1.2~1.3 times as great as the theoretical ones.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.398-404
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• 2017

The aim of this study was to determine the effect of a non-elastic fixation belt on the balance ability and fall prevention in elderly women. Elderly women experience reduced balance ability and an increased risk of falls due to a weakening of the surrounding sacroiliac joint and pelvic muscles during childbirth and menopause. On the other hand, specific studies are still needed. The subjects were allocated randomly to two groups: control (n=20) and experimental (n=20). The experimental group used a non-elastic fixation belt, whereas the control group had no fixation belt. The balance ability and the fall index were measured in all subjects using a balance measurement device, and the low abdominal muscle thickness was determined in the experimental group using ultrasound imaging for the exact application of the non-elastic fixation belt. The following statistical analysis was performed: an independent t-test for the general characteristics of the subjects, $2{\times}2$ analysis of variance with repeated measures for the balance and fall index score, and a paired t-test for the abdominal muscle thickness. The group ${\times}$ time interaction effect showed significant improvement in the General Stability Index (F1,38=47.24, p=0.001), Fourier Harmony Index (F1,38=88.83, p=0.001), Weight Distribution Index (F1,38=50.21, p=0.001), and Fall Index (F1,38=21.59, p=0.001). The thicknesses of the transverse abdominal (p=0.001) and internal oblique (p=0.001) muscles were increased significantly in the experimental group after using the non-elastic fixation belt. Overall, the application of a non-elastic fixation belt could be effective in improving the balance ability and fall prevention in elderly women.