• Korean Journal of Digital Imaging in Medicine
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• v.11 no.1
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• pp.5-13
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• 2009

There are several reasons to take X-ray in case of inpatients. Some of them who cannot ambulate or have any risk if move are taken portable X-ray at their wards. Usually, in this case, many other people-patients unneeded X-ray test, family, hospital workers etc-are indirectly exposed to X-ray by scatter ray. For that reason I try to be aware of free space scatter dose accurately and make the point at issue of portable X-ray better in this study. kVp dose meter is used for efficiency management of portable X-ray equipment. Mobile X-ray equipment, ionization chamber, electrometer, solid water phantom are used for measuring of free space scatter dose. First of all the same surroundings condition is made as taken real portable X-ray, inquired amount of X-ray both chest AP and abdomen AP most frequently examined and measured scatter ray distribution of two tests individually changing distance. In the result of measuring horizontal distribution with condition of chest AP it is found that the mAs is decreased as law of distance reverse square but no showed mAs change according to direction. Vertical distribution showed the mAs slightly higher than horizontal distribution but it isnt found out statistical characteristic. In abdomen AP, compare with chest AP, free space scatter dose is as higher as five-hundred times and horizontal, vertical distribution are quite similar to chest AP in result. In portable X-ray test, in order to reduce the secondary exposure by free space scatter dose first, cut down unnecessary portable order the second, set up the specific area at individual ward for the test the third, when moving to a ward for the X-ray test prepare a portable shielding screen. The last, expose about 2m apart from patients if unable to do above three ways.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.4
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• pp.351-361
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• 2010

Among common estuarine submerged plants, seagrasses are the most extensively studied due to their ecological importance in estuarine ecosystems. Seagrass meadows are important biological habitats for a wide variety of marine animals and plants. They are a source of organic carbon for commercially important animals. Furthermore, seagrasses act as nutrient filters in estuarine and coastal marine ecosystems. As such, mapping the distribution of seagrass beds is important for management and conservation strategies. In order to survey the seagrass distribution within the Seomjin Estuary, We directly observed seagrass beds in Kwangyang and Hadong using SCUBA. The distribution area, species composition, morphology, density, biomass and productivity of seagrass meadows were examined. Seagrass meadows were distributed in the intertidal and subtidal zones of the Galsa tidal flats, and in the subtidal zone of the neighboring POSCO area. Patches of Zostera japonica was found at patches at the Galsa tidal flats intermediate point. The total estimated seagrass distribution area of the Seomjin Estuary was $1.84\;km^2$. Of the total, $1.83\;km^2$ was Zostera marina (eelgrass) and $0.01\;km^2$ was Zostera japonica (dwarf eelgrass). Zostera japonica was found in intertidal zones. Zostera marina was found from the intertidal to subtidal zones at a 2 m mean sea level (MSL) depth. The leaf productivity of Zostera marina was $4.47g\;DW\;m^{-2}\;day^{-1}$. The annual production of eelgrass was $1,632\;g\;DW\;m^{-2}\;yr^{-1}$, which corresponds to $731g\;C\;m^{-2}\;yr^{-1}$. The total production of eelgrass was $3,002\;tons\;DW\;yr^{-1}$, which corresponds to $1,343\;tons\;C\;yr^{-1}$.

• Journal of the Korean association of regional geographers
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• v.10 no.1
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• pp.158-176
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• 2004

The purpose of this paper is to clarify the distribution system and the spatial characteristics of sales for the internet shopping mall on the basis of its off-line presence. The distribution system of this internet shopping mall is divided into the goods selection process and the product delivery process to consumers according to the function and role of the distribution center which is performed by cooperative companies. The internet shopping mall uses a different distribution system from the off-line department store, outsourcing the delivery process to door-to-door delivery companies in order to reduce costs and to increase the speed of delivery. Sales in the internet shopping mall are concentrated in the delivery unit area where the main office is located. Accordingly, in the case of the internet shopping mall based on an off-line presence, the mail-order business does not fully overcome the limitations arising from space. Also, the main factors influencing the value of sales, according to the area, are the number of women aged 20 to 49 and the distances involved.

• Journal of Environmental Health Sciences
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• v.44 no.4
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• pp.360-369
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• 2018

Objectives: Outdoor tobacco smoke can penetrate into the indoor environment through cracks in the building envelope. This study aimed to characterize the particle size distribution of infiltrated secondhand smoke (SHS) through the gap in a single glazed and a secondary glazed window according to pressure differences in a chamber. Methods: Two polyvinyl chloride sliding windows were evaluated for infiltration, one with a glazed window and the other with a secondary glazed window. Each window was mounted and sealed in a polycarbonate chamber. The air in the chamber was discharged to the outside to establish pressure differences in the chamber (${\Delta}P$). Outdoor smoking sources were simulated at a one-meter distance from the window side of the chamber. The particle size distribution of the infiltrated SHS was measured in the chamber using a portable aerosol spectrometer. The particle size distribution of SHS inside the chamber was normalized by the outdoor peak for fine particles. Results: The particle size distribution of SHS inside the chamber was similar regardless of window type and ${\Delta}P$. It peaked at $0.2-0.3{\mu}m$. Increases in particulate matter (PM) concentrations from SHS infiltration were higher with the glazed window than with the secondary glazed window. PM concentrations of less than $1{\mu}m$ increased as ${\Delta}P$ was increased inside the chamber. Conclusions: The majority of infiltrated SHS particles through window gap was $0.2-0.3{\mu}m$ in size. Outdoor SHS particles infiltrated more with a glazed window than with a secondary glazed window. Particle sizes of less than $1{\mu}m$ were associated with ${\Delta}P$. These findings can be a reference for further research on the measurement of infiltrated SHS in buildings.

• Journal of the Korean Electrochemical Society
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• v.12 no.4
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• pp.317-323
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• 2009

Theoretical calculations for the secondary current distributions for the electrode with a projection part in electroplating were performed. Two kinds of electrodes were considered. One is a electrode with the overall conducting surfaces(Case 1) and the other is an electrode in which only a projection part has a conducting surface(Case 2). The effects of applied potential, the ratio of ion exchange current to conductivity, $\xi$ and the aspect ratio on the current distribution were examined. The increase of applied current or the value of $\xi$ decreased the uniformity of current distribution. The small value of aspect ratio resulted the more uniform current distribution and Case 2 showed the better uniformity than Case 2. When this model was applied into an electrode with various projection parts, the local current distribution along the electrode surface were obtained successfully. In this case, the decrease of $\xi$ also increase the uniformity of current distribution as seen previously.

• Korean Journal of Ecology and Environment
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• v.53 no.2
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• pp.185-194
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• 2020

Pomacea canaliculate (channeled apple snail; CAS), which is one of the world's worst alien invasive species, is widely distributed in Korea, and raised ecological and economic problems. In this study, we surveyed the distribution and dispersal characteristics of CAS in Korea, and analyzed the effects of environmental and anthropogenic (or social) factors on their distribution and dispersal. We considered various events related to CAS such as changes of policy including promotion of agriculture using CAS and enactment of biological diversity conservation law. Our results showed that human activities strongly influenced to the distribution and dispersal of CAS in Korea. Distribution of CAS seemed to relate with environment-friendly agriculture considering environmental conditions of CAS habitats. And dispersal characteristics of CAS were significantly correlated with social factors such as cultivation area and rate of organic products, production CAS on inland fishery.

• Journal of the Economic Geographical Society of Korea
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• v.16 no.3
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• pp.512-527
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• 2013

This study examines the spatial distribution characteristics of financial industry which has been a necessary service for contemporary urban life. In particular, we analyze the spatial distribution patterns of money lending business which is considered with informal financial services as well as the spatial distribution patterns of banks which are representative of the institutional financial services. For the purpose, their density distribution patterns are explored by Kernel density analysis for both financial services in first. Moran's I coefficients are estimated for these two financial services to clarify the distintion in their geographical concentration patterns. The results of spatial autocorrelation analysis show stark differences between the center city and outskirts of the Seoul metropolitan area. Multivariate regression models are developed to explain the relationships between the spatial distributions of financial services and geographical variables. Finally, we discuss financial exclusion problem in the Metropolitan Seoul based on these spatial distribution characteristics.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.2
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• pp.177-194
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• 1991

The purpose of this study was to analyze the magnitude and distribution of stress using a photoelastic model from a distal extension removable partial dentures with three kinds of mandibular major connectors, that is, lingual bar, linguoplate, and swing-lock attachment. A photoelastic model was made of the epoxy resin(PC-1) and hardener(PCH-1) and coated with plastic cement-1 (PC-1) at the lingual surface of the epoxy model and set with three kinds of chrome-cobalt removable partial dentures. A bilateral vertical load of 15kg to the middle portion of the metal bar crossing both the first molars of the right and the left, and a unilateral vertical load of 12.5kg to the right first molar were applied with the use of specially designed loading device and the reflective circular polariscope was used to analyze the photoelastic model under each condition. The following results were obtained : 1. When the bilateral vertical load was applied, the magnitude and distribution of the stress concentration of the edentulous area and the terminal abutment or adjacent teeth was in the order of lingual bar, linguoplate, swing-lock attachment. 2. When the unilateral vertical load was applied, the magnitude and distribution of the stress concentration of the edentulous area and the terminal abutment or adjacent teeth was in the order of lingual bar, linguoplate, swing-lock attachment. 3. When the unilateral vertical load was applied, the magnitude and distribution of the stress concentration of the termial abutment or adjacent teeth on the non-loaded side showed the least stress distribution in case of swing-lock attachment. 4. When the bilateral vertical load and the unilateral vertical load were applied the swing-lock attachment showed the mildest uniform stress distribution on the edentulous area and the alveolar bone around the abutment teeth.

• Ocean and Polar Research
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• v.24 no.3
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• pp.255-261
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• 2002

We investigated the distribution of sea ice using Topex/Poseidon (T/P) and ERS-1 .ada. altimeter data in the northwest Weddell Sea, Antarctica, between the area $45-75^{\circ}W\;and\;55-66^{\circ}S$. Using the Geo_Bad_1 flag of the Merged GDR of the T/P, we classified the surface into ocean, land, and sea. Total 257 cycles of altimeter measurements between Oct. 1992 and Sep. 1999 (for nearly 2570 days) were used to analyze the distribution of the Antarctic sea ice. We then calculated the surface area of ice coverage using SUTM20 map projection to monitor the periodic variations. Each year, the maximum and minimum coverage of the sea ice were found in late August and February in the study area, respectively. We also studied the sea ice distribution using ERS-1 altimeter data between $45-75^{\circ}W\;and\;55-81.5^{\circ}S$ to compare with the T/P Using the Valid/Invalid flag of the Ocean Product, we analyzed the sea ice distribution between March and August of 1995, which showed very good coherence with the T/P measurements. Our preliminary results showed that the altimeter measurements can be effectively used to monitor the distribution of the sea ice in the polar region. However, the size of radar footprint, typically 2-6km depending on the roughness of the sea surface, may be too big to monitor the sharp boundary between ice and water/land. If more other altimeter mission data with dense coverage such as Geosat GM are analyzed together, this limitation can be significantly improved. If we also combine other microwave remote sensing data such as radiometer, and SSM/I, the result will be significantly enhanced.

• The Korean Journal of Applied Statistics
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• v.29 no.5
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• pp.987-998
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• 2016

Auto insurance is an insurance product that requires the proper application of pricing techniques due to intense market competition and the rate regulations of financial authorities. Especially, population change according to aging and rating faction segmentation mainly affect the pricing process. This study suggests a pricing optimization methodology through the proper estimation of age factors. To properly estimate the future distribution of age factor, age change, renewal and conversion of customers are considered as main effects for the optimization of estimation and application. The properness and effectiveness for the suggested method will be proved by a comparison of results applied (one for current distribution and the other for future distribution) at the off-balance process. This study suggests an appropriate risk estimation methodology based on optimization that uses the proper estimation of future distribution to protect from the over or under estimation of risk.