• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3317-3323
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• 2022

Half Value Layer calculations theoretically need prior specification of linear attenuation calculations, since the HVL value is derived by dividing ln(2) by the linear attenuation coefficient. The purpose of this study was to establish a direct computational model for determining HVL, a vital parameter in nuclear radiation safety studies and shielding material design. Accordingly, a typical gamma-ray transmission setup has been modeled using MCNPX (version 2.4.0) general-purpose Monte Carlo code. The MCNPX code's INPUT file was designed with two detection locations for primary and secondary gamma-rays, as well as attenuator material between those detectors. Next, Half Value Layer values of some well-known gamma-ray shielding materials such as lead and ordinary concrete have been calculated throughout a broad gamma-ray energy range. The outcomes were then compared to data from the National Institute of Standards and Technology. The Half Value Layer values obtained from MCNPX were reported to be highly compatible with the HVL values obtained from the NIST standard database. Our results indicate that the developed INPUT file may be utilized for direct computations of Half Value Layer values for nuclear safety assessments as well as medical radiation applications. In conclusion, advanced simulation methods such as the Monte Carlo code are very powerful and useful instruments that should be considered for daily radiation safety measures. The modeled MCNPX input file will be provided to the scientific community upon reasonable request.

• 대한안전경영과학회지
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• 제15권3호
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• pp.1-6
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• 2013

This study was conducted to compare the value of the working environment measurement with the expected exposure value drawn by using a program, thereby going to investigate whether it is available to the risk assessment of domestic workplace. We used the ECETOC TRA program which is one of the exposure predictive models. Four kinds of substances were measured in two workplace which was exposed to organic solvents and one kind of substance was measured in three workplace which was exposed to dusts and then an exposure assessment of chemical risk factors was conducted. The result value of the working environment measurement, solid substance exceeded standard in one site, and it was found that the other solid and liquid substances were within the standard. The value of the exposure assessment program showd the same result; it was higher than the value of the working environment measurement, suggesting that due to its nature, the exposure assessment program is run only on the worst situation. Therefore, it was found that when the exposure assesment program is used, variables should be substituted only after accurately assessing the workplace and it is a good idea to assess the risk beforehand with the exposure assessment program in the case of the workplace which employs no more than 5 people and where it is hard to assess the working environment.

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 1994년도 교수 연수회(환경)
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• pp.440-449
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• 1994

Current risk assessment practices largely reflect the need for a consistent set of relatively rapid, first-cut procedures to assess 'plausible upper limits' of various risks. These practices have important roles to play in 1) screening candidate hazards for initial attention and 2) directing attention to cases where moderate-cost measures to control exposures are likely to be warranted, in the absence of further extensive (and expensive) data gathering and analysis. A problem with the current practices, however, is that they have led assessors to do a generally poor job of analyzing and expressing uncertainties, fostering 'One-Number Disease' (in which everything from one's social policy position on risk acceptance to one's technical judgment on the likelihood of different cancer dose-response relationships is rolled into a single quantity). At least for analyses that involve relatively important decisions for society (both relatively large potential health risks and relatively large potential economic costs or other disruptions), we can and should at least go one further step - and that is to assess and convey both a central tendency estimate of exposure and risk as well as our more conventional 'conservative' upper-confidence-limit values. To accomplish this, more sophisticated efforts are needed to appropriately represent the likely effects of various sources of uncertainty along the casual chain from the release of toxicants to the production of adverse effects. When the effects of individual sources of uncertainty are assessed (and any important interactions included), Monte Carlo simulation procedures can be used to produce an overall analysis of uncertainties and to highlight areas where uncertainties might be appreciably reduced by further study. Beyond the information yielded by such analyses for decision-making in a few important cases, the value of doing several exemplary risk assessments in. this way is that a set of benchmarks can be defined that will help calibrate the assumptions used in the larger number of risk assessments that must be done by 'default' procedures.

• 혜화의학회지
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• 제24권1호
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• pp.25-36
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• 2015

Objective : This study aims to evaluate a risk of bias by Risk of Bias tool and RoBANS(Risk of Bias Assessment tool for Non-randomized Study) tool for clinical trial papers proving treatment effect of herbs to alopecia and provides the newest reason of effectiveness of herbs to alopecia. Methos : Data were collected through electronic database including NDSL, KISS, KMBASE, Koreantk, OASIS, KoreaMed, KISTI, Pubmd, Cochrane CENTRAL and CINAHL. Two experts in Oriental Medince assessed risk of bias of randomized controlled trials by Cochrane group's Risk of Bias tool and non-randomized controlled trials by RoBANS tool after searching, reviewing and selecting papers. Results : Total number of selected trials is 20 including 4 randomized controlled trials, 13 non-randomized controlled trials and 3 case reports. This study evaluates the risk of bias of 17 papers including 4 randomized controlled trials and 13 non-randomized controlled trials except 3 case reports by risk of bias tool and RoBANS tool. All papers of randomized controlled trials are evaluated unclear for random sequence generation and allocation concealment as there are no word on them. And all papers of non-randomized controlled trials are evaluated unclear for blinding of outcome assessments and relatively low for others. Conclusion : We must try to specify concretely methods of allocation concealment after planning and practicing it for reducing a selection bias in randomized controlled trials. Also report a reason of missing value and blinding outcome assessments. And we have to agonize and mention methods of blinding of researchers for reducing a detection bias in non-randomized controlled trials.

• 한국문헌정보학회지
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• 제44권4호
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• pp.155-178
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• 2010

Assessment of information credibility is a ubiquitous human activity given that people constantly make decisions and selections based on the value of information in a variety of information seeking and use contexts. Today, people are increasingly engaging in diverse online activities beyond searching for and reading information, including activities such as creating, tagging and rating content, shopping, and listening to and watching multimedia content. The Web 2.0 environment presents new challenges for people because the burden of information evaluation is shifted from professional gatekeepers to individual information consumers. At the same time, however, it also provides unprecedented opportunities for people to use tools and features that help them to make informed credibility judgments by relying on other people's ratings and recommendations. This paper introduces fundamental notions and dimensions of credibility, and contends that credibility assessment can be best understood with respect to human information behavior because it encompasses both the level of effort people exert as well as the heuristics they employ to evaluate information. The paper reports on a survey study investigating people's credibility judgments with respect to online information, focusing on the constructs, heuristics, and interactions involved in people's credibility assessment processes within the context of their everyday life information activities. Using an online activity diary method, empirical data about people's online activities and their associated credibility assessments were collected at multiple points throughout the day for three days. The results indicate that distinct credibility assessment heuristics are emerging as people engage in diverse online activities involving more user-generated and multimedia content. A heuristic approach suggests that people apply mental shortcuts or rules of thumb in order to minimize the amount of cognitive effort and time required to make credibility judgments. The paper discusses why a heuristic approach is key to reaching a more comprehensive understanding of people's credibility assessments within the information-abundant online environment.

• 한국콘텐츠학회논문지
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• 제18권1호
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• pp.108-116
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• 2018

본 연구의 목적은 정상 집단과 성대결절 집단의 음성을 음향학적 측정(AVQI), 청지각적 평가(GRBAS, CAPE-V)를 수행하여 그 차이와 상관관계를 조사하는 것이다. 이를 위해 성대결절 환자 335명의 음성 샘플을 음향학적으로 분석하고, 3명의 평가자를 통해서 청지각적 평가를 실시하였다. 연구결과, 정상 집단의 AVQI, grade(G), overall severity(OS) 점수는 성대결절 집단의 점수보다 낮게 평가되었다. 청지각적 척도간의 상관관계에서는 GRBAS의 G 척도와 CAPE-V의 OS 척도는 상관관계가 높은 것으로 나타났고, 음향학적 측정 AVQI와 G, OS 간의 상관관계도 높은 것으로 확인되었다. 두 집단 간의 AVQI, G, OS를 감별하는 역치값은 각각 ${\leq}4.06$, ${\leq}1$, ${\leq}26$ 였으며, 예측진단력은 0.840, 0.860,0.848이었다. 결론적으로 AVQI와 청지각적 평가를 통하여 성대결절 음성에 대한 선별 가능성을 높일 수 있고, 음성장애의 진단 및 치료 계획수립에 도움을 줄 것으로 사료된다.

• 한국컴퓨터정보학회논문지
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• 제19권5호
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• pp.119-128
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• 2014

본 연구는 초등학교 학생들에게 디지털 스토리텔링을 활용한 프로그래밍 교육을 실시하고 프로그래밍에 대한인식, 인지적-정의적 평가, 인터뷰를 통해 교육적 의미를 분석하였다. 연구 결과는 다음과 같다. 첫째 사후 인식 결과 즐거움(fun), 유용성(usefulness), 용이성(ease of use) 모든 영역에서 통계상 유의미한 차이를 보였으며 여학생들도 남학생과 유사하게 긍정적인 인식을 갖고 있는 것으로 나타났다. 둘째, 사전-사후 인지적 평가결과에서 유의미한 차이가 나타났다. 셋째, 정의적 측면으로 수업이 진행될수록 '즐거움'을 느끼는 학생의 숫자가 지속적으로 증가하는 것으로 나타났다. 이러한 연구 결과는 프로그래밍 교육에서 디지털 스토리텔링의 교육적 가치를 확인시켜주는 것으로 향후 초등학생의 프로그래밍 교육 방안에 대한 기초자료로 활용될 것으로 기대된다.

• 한국패류학회지
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• 제22권2호
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• pp.167-173
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• 2006

The embryos of marine bivalves have been commonly used in bioassays for quality assessments of marine environments. Although several standard protocols for the developmental bioassay of bivalves have been proposed, only a few trials for application of these protocols in environmental assessments or for the development of a new protocol with Korean species have been conducted. As such, there is a strong need to establish standard bioassay protocols with bivalves commonly found in Korean waters. To determine the sensitivity of Mytilus galloprovincialis to establish a standard bioassay, their fertilized eggs were exposed to six metals (Ag, Cd, Cr, Cu, Ni, and Zn). The order of biological impact was Ag > Cu > Ni > Zn > Cr > Cd and their lowest observed effective concentration were 5, 16.4, 25.4, 142, 187 and 1,500${\mu}g/l$, respectively. The proportion of normal larvae appeared to decrease linearly with the logarithm of each toxicant concentration within the tested range. The average values of median effective concentrations $(EC_{50})$ from the triplicate experiments for Ag, Cd, Cr, Cu, Ni, and Zn were 6.8, 1,797, 786, 16.6, 68.1, and 139.2${\mu}g/l$, respectively. There was a more than 100-fold difference in $EC_{50}$ values of Cu and Cd. The value of $EC_{50}$ or median lethal concentration of Cu was within the range observed for other bivalve developmental bioassays. The overall sensitivity of M. galloprovincialis in the present developmental bioassay was also similar to that of other marine organisms commonly used in aquatic bioassays (e.g. sea urchins, oysters). Hence, the bioassay using the embryo of M. galloprovincialis is considered to be a useful tool to monitor and evaluate the quality of marine aquatic environments.

• IEIE Transactions on Smart Processing and Computing
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• 제2권5호
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• pp.255-265
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• 2013

3DTV is expected to be a promising next-generation broadcasting service. On the other hand, the visual discomfort/fatigue problems caused by viewing 3D videos have become an important issue. This paper proposes a perceptual quality assessment metric for a stereoscopic video (SV-PQAM). To model the SV-PQAM, this paper presents the following features: temporal variance, disparity variation in intra-frames, disparity variation in inter-frames and disparity distribution of frame boundary areas, which affect the human perception of depth and visual discomfort for stereoscopic views. The four features were combined into the SV-PQAM, which then becomes a no-reference stereoscopic video quality perception model, as an objective quality assessment metric. The proposed SV-PQAM does not require a depth map but instead uses the disparity information by a simple estimation. The model parameters were estimated based on linear regression from the mean score opinion values obtained from the subjective perception quality assessments. The experimental results showed that the proposed SV-PQAM exhibits high consistency with subjective perception quality assessment results in terms of the Pearson correlation coefficient value of 0.808, and the prediction performance exhibited good consistency with a zero outlier ratio value.

• 농촌계획
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• 제20권1호
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• pp.27-36
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• 2014

The purposes of this study are to identify assessment items to evaluate riverfront for amenity and recreation and to analyze the relative importance of the items using Analytic Hierarchy Process(AHP). Total 15 items of 5 categories were identified through literature review and panel discussion. Based on the AHP analysis results, a weighted value was set for each of the layers in the hierachy. 'Ecological Characteristics' (0.333) was rated with the highest weighted value. followed by 'Landscape Characteristics'(0.190) and 'Physical Characteristics'(0.166). Among the assessment items, 'Water Quality' (0.152) and 'River Naturality'(0.118) had higher weighted values. With the set of assessment items field assessments were carried out for Gyung-An Stream of Gyeonggi-Do to exam its applicability. Total 6 segments and 31 reaches out of the 22.5 km long river were evaluated and the mean scores of the five categories were converted into a percentile score for comparison. Overall, the segments which had higher scores were located close to neighborhood areas and had better connections with other historical and cultural amenities. Also, existing facilities was an important factor and needs to be considered for waterfront development.