• Journal of Radiation Protection and Research
• /
• v.38 no.1
• /
• pp.29-36
• /
• 2013

The aim of this study was to determine the correlation between exposure index (EI) and dose factors related to radiation dose optimization in digital radiography (DR) system. Two phantoms with built-in regional test object for quantitative assessment of images were used to produce image signals that acquired in chest radiography background. EI and entrane surface dose (ESD) increased proportionally with rise of radiation dose (kVp, mAs) in both DR and CR systems. Especially, DR detector was effective to form good contrast and hence, reached easily to improvement of image quality with minimal dose changes. It made operators possible to expect the accuracy of EI values deeply related to absorbed dose of the detector. The evaluation of images was obtained specially employed calculation of noise to signal ratio (NSR) and contrast to noise ratio (CNR). These measurements were performed for how exposure factors affect image quality. NSR was inversely proportional to kVp and mAs and low NSR represented high signal detection efficiency. Consequently, EI values was the measure of the amount of exposure received by the image receptor and it was proportional to exposure factors. Therefore the EI in a recommended range from manufacturer can offer optimal image quality. Also, continuous monitoring of EI values in the digital radiography can reduce the unnecessary patient dose and help the quality control of the system.

• The Korean Journal of Malacology
• /
• v.14 no.2
• /
• pp.113-120
• /
• 1998

참굴에 다환성방향족탄화수소(PAHs)의 축적성과 이 물질들이 미치는 독성을 평가하기 위해 해양환경에서 빈번히 검출되는 PAHs 중의 하나인 anthracene을 사용한 모델연구를 수행하였다. Anthracene을 0.01-1ppm의 농도로 2주간 참굴에 노출시켰을 때 참굴 조직내의 anthracene의 농도는 노출기간 및 노출강도에 비례하여 최고 25-85배까지 증가하였다. 소화맹낭과 폐각근의 지질 과산화물가는 노출기간 및 노출농도에 관련하여 현저히 증가하였으나 수용성단백질, glycogen, nucleoside/nucleotide 및 핵산의 함량은 변화하지 않았다. 이 결과로 anthracene은 굴의 조직내로 원할하게 축적됨을 확인하였으며 과산화지질의 함량은 anthracene에의 오염에 대한 예민한 생화학적 지표가 될 수 있을 것으로 사료된다.

• Korean Journal Plant Pathology
• /
• v.11 no.2
• /
• pp.107-115
• /
• 1995

들깨 '수원25호', 담배 'L8', 'KF109'와 'NC82', 시금치 '입추'와 나팔꽃을 생장혼경조절이 가능한 대기오염원 노출상에서 SO? 140ppb/시간 또는 O? 150ppb/시간의 농도로 하루 24시간 10일 동안 노출시킨 결과 '수원25호' 들깨와 담배 'L8'은 SO?에 민감한 반면, 담배 'L8'과 나팔꽃은 오존에 아주 민감한 것으로 판명되었다. 위의 농도에서 가시적 피해가 조사식물의 50%에서 발생하는 병반발생빈도 50%(SF?)를 기준으로 설정한 한계노출시간 조사에서 오존에 대한 한계 노출시간은 담배 'L8'의 경우 24시간, 나팔꽃의 경우 72시간, 담배 'NC82'와 'KF109'의 경우 144시간 내외, 시금치의 경우 216시간으로 추정되었으며, SO?에 대한 한계노출시간은 담배 'L8'의 240시간을 제외하고는 모든 식물에서 240시간 이상으로 추정되었다.

• Spatial Information Research
• /
• v.19 no.3
• /
• pp.1-9
• /
• 2011

The vulnerability of ocean should be assessed to establish the climate change adaptation policy in field of the ocean, which has big effect on human and natural system. In this study, the criteria for assessing vulnerability of ocean to climate change were employed in terms of sensitivity, adaptative capacity and exposure. And suitable indicators for the criteria were selected and spatial data set for the indicators was prepared. In the ocean sector, the data for indicators were divided into two types, such as the inland and ocean data. The inland data were extrapolated and integrated to the coordinate of ocean data for the vulnerability assessment to climate change. As a result, the spatially diverse distribution of vulnerability on the ocean could be derived from the integration of two types of data. The results showed that southwestern ocean is much more sensitive than west and east ocean. Also southwestern ocean of exposure ratio of change is higher than the other part of ocean. On the other hand the adaptative capacity found that the highest in east ocean. The vulnerability assessment result showed southwestern ocean is more vulnerable than the other part of ocean.

• Journal of the Economic Geographical Society of Korea
• /
• v.18 no.1
• /
• pp.1-16
• /
• 2015

It is widely believed that increasing socio-economic polarization inspired by globalization and economic restructuring worsens residential segregation by class in Korean cities. However, the existing literature falls short in showing the recent changes of the residential segregation, particularly after the 1997 financial crisis, with reliable and systematic segregation measures. Noting that there are the two major dimension in residential segregation - evenness-concentration and exposure-clustering - this study introduced not only global measure (dissimilarity index and isolation/interaction index) but also local measures (location quotient and Local Moran's I) for each dimension. These measures are applied to the case study of Seoul in the 2000s. The class is defined by education attainment and the data is obtain through the MicroData System Service System(MDSS). The result shows that the residential segregation by education attainment persists through 2000s and even get worse in some dimension. More significantly, it turns out that high-class and low-class residence are nearly mirror-images of each other, indicating high segregation.

• Korean Journal of Ecology and Environment
• /
• v.52 no.1
• /
• pp.13-20
• /
• 2019

Heavy metals resulted from the increase of human industrial activity are introduced into the environment through rainfall and wastewater, and have harmful effects on inhabitants. In this study, we investigated biological responses such as survival rate, growth rate, emergence rate and sex ratio, and morphological effects of mentum deformity in Chironomus plumosus, an indicator organism to evaluate pollutions on aquatic ecosystem. The survival rate of C. plumosus showed time- and dose-dependent decrease after chromium and copper exposures. Growth rate decreased at $4^{th}$ day after chromium exposure and significantly reduced at exposure to relatively high concentration (copper $1000mg\;L^{-1}$) for all exposure times. In addition, we observed that the emergence rate by exposure to copper $1000mg\;L^{-1}$ was significantly lower than that of the control group. The imbalance of sex ratios showed at relatively low concentrations (chromium 10 and $50mg\;L^{-1}$) with the high proportion of female and at the relative high concentration (copper $1000mg\;L^{-1}$) with the high proportion of male. Furthermore, the morphological mentum deformities of C. plumosus observed in the exposed group according to chromium and copper exposure. These results suggest that the heavy metal exposure in environment may influence biosynthetic and morphological stresses of benthic invertebrate C. plumosus, and aquatic midge C. plumosus are potential indicators for toxicity assessment of heavy metals such as chromium and copper.

• The Journal of the Korea Contents Association
• /
• v.17 no.7
• /
• pp.12-21
• /
• 2017

In this study, we divided attention to mobile contents into two dimensions (i.e., exposure and involvement), and explored the characteristics of and the relationship between the attention behaviors, using contents data from Pikicast. First, this study investigated the relationship between exposure and involvement in order to examine whether double-jeopardy effects appear in mobile contents as well. In addition, we examined how different attention behaviors differ according to platform and subject attributes(i.e., soft and hard). As a result, we found that there was a positive correlation between exposure and involvement in mobile platforms. Also, we found that the attention behaviors, especially sharing behaviors, were different in each platform. In terms of subject attributes, the attention indices such as the number of comments and sharing, which were immediate responses, were related to the soft content, whereas the attention indices such as the consumption time and the complete-read rate were related to the hard content requiring cognitive effort.This study is meaningful to understand the essence of the attention behavior in the mobile environment from a content - oriented perspective rather than the most existing research with a user - centered perspective.

• Journal of Korean Society of Disaster and Security
• /
• v.6 no.1
• /
• pp.73-78
• /
• 2013

This study aims to develop Drowning Management Index (DMI) to evaluate the effectiveness of drowning management in a region. In order to develop practical index to evaluate drowning management, downing contributors are examined. Drowning exposure rate is collected by survey. DMI is generated from South Korea and Australia for comparison. South Korea and Australia indicate similar number of drowning per 100 thousand people (1.7 South Korea, 1.4 Australia) but in DMI it turned out 9 times difference between two countries (15.5 South Korea, 1.67 Australia).

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2013.11a
• /
• pp.55-56
• /
• 2013

소방보호복의 열보호특성을 정확히 파악하는 것은 보호복 개발 뿐만 아니라 화상에 의한 부상 방지 및 생명 보호라는 측면에서 매우 중요하다. 하지만 대부분의 경우 고열유속 조건에서 시험을 수행하여 시편의 파괴가 발생하기 쉽고, 그에 의해 제대로 된 결과를 얻어낼 수 없는 경우가 많다. 따라서 본 연구에서는 저열유속 조건의 복사열 노출시 열보호성능을 효과적으로 제시할 수 있는 지표 및 측정 방법을 기존 RPP (Radiant Protective Performance) 측정방법을 개선하여 제안하였다. 또한 실험을 통해 여러 가지 보호성능지표들의 관계를 파악하였다.

• Journal of Korean Society of Transportation
• /
• v.17 no.2
• /
• pp.105-114
• /
• 1999

The pattern of traffic streams in residential streets is different from the ordinary roads separated by pedestrian and car lanes. Such fact makes it difficult to evaluate the new counter-measures with existing indices and methods. In this study, a unified, consistent new method is introduced as Time-Space Occupancy (TSO) concept. An application of TSO concept will suggest a TSO exposure volume index which can show the decree of danger in residential streets where vehicles, pedestrian and other traffic streams are interacted. The validity of TSO exposure volume index will be verified through the survey conducted in Seoul and the subjects will be the residents who live at various kinds of residential streets.