• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.429-429
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• 2021

2019년 발생한 인천광역시 붉은 수돗물 사태로 급수구역에 포함된 26만 1천 세대, 63만 5천 명이 직·간접적인 피해를 입은 바 있다. 경제적 피해액으로 추정할 경우 최소 1,280억 원 이상으로 보고된 바 있으며, 이와 같은 상수관망의 수질사고 확산은 장기간 동안 시민의 건강과 생활환경 수준을 저하시킨다. 따라서 상수도시스템의 수질사고확산 모델링 및 방지기술을 통한 수질안전성의 재확인이 필요하며, 이것은 상수도시스템의 지속가능성을 높여 국민이 체감하는 물 환경 수준 제고에 기여가 가능하다. 관망 내 수질해석을 직접적으로 수행하는 모델은 국외적으로 다양하게 개발(PODDS, EPANET-MSX, EPANET2.2 등)된 바 있으나 검·보정을 위한 수질측정 자료 부족 등으로 적용이 제한적이라는 한계가 현재에도 존재한다. 이를 보완하기 위해 수질자료에 비해 그 양이 많고 획득방법이 상대적으로 수월한 수리학적 계측자료 및 해석결과를 활용한 관로 내 체류시간 등을 활용한 연구가 수행된 바 있다. 그러나 이와 같은 수리학적 해석 결과를 활용하는 경우에도 계측자료를 기반으로 한 수리학적 검·보정은 필수적이라 할 수 있다. 본 연구에서는 관로 내 체류시간에 직접적인 영향을 미치는 유량 및 유속자료를 중심으로 수리학적 관망해석의 결과를 최적 검·보정하는 방법론을 제안하였다. 기존 상수관망 수리해석의 검·보정은 일부 지점에서 수압을 측정하고, 수리해석 결과로 도출되는 해당 지점의 수압이 실측된 결과와 유사하도록 관로의 유속계수를 적절히 보정하는 형태로 진행되었다. 그러나 본 연구에서는 관로유량과 유속자료의 목적함수 내 가중치를 수압자료보다 크게 설정하여 체류시간 중심의 검·보정이 수행될 수 있도록 하였으며, 검·보정 대상인자 역시 대수용가의 수요량, 수요패턴, 그리고 관로유속계수로 확장된 모형을 구축하였다. 최적화 기법으로는 메타휴리스틱 기법중 하나인 화음탐색법을 활용하였다. EPANET 2.2 Toolkit과 Visual Basic .Net을 연계하여 프로그래밍하였으며, 개발된 모형을 실제 지방상수도 시스템에 적용하여 분석하였다.

• Journal of the Korean Chemical Society
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• v.26 no.4
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• pp.229-234
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• 1982

Using solution technique, sulfur in the sulfide ore was indirectly determined by X-ray fluorescence spectrometry. The sample was dissolved with the mixed solution of B$r_2$ and HN$O_3$, and Si$O_2$, a major constituent, was repelled from the solution by HF treatment several times, B$a^{2+}$ solution was added to the solution to precipitate the S$O^4_{2-}$ ion as BaS$O_4$. Measuring the fluorescent X-ray intensity of excess Ba2+ ion in the filtrate, the content of sulfur in the original ore was back-calculated. Comparing the results by this method with the gravimetric method, the mean difference was ${\pm}1.7%$ in the range of 20 to 40% of sulfur content and the method was tolerably reproducible.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.592-598
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• 2017

A method for estimating the optical characteristics of ceramic materials under high temperature conditions has been applied and evaluated. For that purpose, an interface system combined with a photo-spectrometer was made to keep the samples at the required high temperature. The transmittance of the samples was measured at various temperatures. The measured transmittance data was used to estimate the refractive index using an optical simulation model in conjunction with the Sellmeier equation. The Sellmeier equation parameters were selected by trial-and-error when the transmittance recalculated using the estimated refractive index was compared with the measured transmittance. Furthermore, the estimated refractive indices were checked by a comparison with the reference data at some typical wavelengths at room temperature.

• Journal of the Korean Society for Library and Information Science
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• v.43 no.4
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• pp.117-137
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• 2009

This study aims to grasp how to understand the difference in return on investment (ROI) or the cost-benefit ratio in forty-two domestic and overseas studies of library valuation, using a meta-analytical review method. Meta-analysis, a quantitative analysis on the findings of previous studies, was conducted to gather the general findings and lessons from prior empirical research. The results of meta-regression analysis indicate that the pattern of findings is consistent with our expectations regarding the effect of benefit scope and per capita GDP included in the ROI figure. This study appears to be the first meta-analytical review conducted on library valuations and the findings provide strong implications for the policy-making process.

• Journal of Software Assessment and Valuation
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• v.16 no.1
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• pp.37-44
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• 2020

The similarity of the software is extracted by the verification of comparing with the source code. The source code is the intellectual copyright of the developer written in the programming language. And the source code written in text format contains the contents of the developer's expertise and ideas. The verification for judging the illegal use of software copyright is performed by comparing the structure and contents of files with the source code of the original and the illegal copy. However, there is hard to do the one-to-one comparison in practice. Cause the suspected source code do not submitted Intentionally or unconsciously. It is now increasing practically. In this case, the comparative evaluation with execution code should be performed, and indirect methods such as reverse assembling method, reverse engineering technique, and sequence analysis of function execution are applied. In this paper, we analyzed the effectiveness of indirect comparison results by practical evaluation . It also proposes a method to utilize to the system and executable code files as a verification results.

• Journal of radiological science and technology
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• v.47 no.5
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• pp.385-394
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• 2024

This study is suggest the importance of a safety management system against radiation exposure by measuring the surface pollution level of toilets in the radiation management area of hospitals using open seafarers and evaluating the spread. The experiment measured 10 times in front of the toilet and the entrance before and after the start of work in 3 toilets in the radiation management area of a hospital in the metropolitan area. The measuring instruments and samples were measured using an indirect measuring smear paper and a surface contamination radiation meter. As a result of the measurement the front of the left toilet in the iodine treatment room bathroom before decontamination exceeded the legally permitted surface contamination dose. All other areas were measured below the legally permitted surface contamination dose. However even if radioactive contamination is below the allowable dose pollutants and contamination conditions must be properly identified and managed with constant attention and attention. Therefore the use of toilets in the radiation control zone must be regulated so that only patients can use them and efforts must be made to minimize the spread of surface contamination outside the toilet by allowing the use of the exclusive use of toilets.

• Composites Research
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• v.19 no.5
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• pp.20-27
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• 2006

Self-sensing and interfacial evaluation of Ni nanowire/polymer composites were investigated using electro-macromechanical technique, which can be used fur a feasible sensing measurement on tensile and compressive loading/consequent unloading, temperature, and humidity. Mechanical properties of Ni nanowire with different aspect ratio and adding contents in either epoxy or silicone composites were measured indirectly using electro-pullout test under uniform and non-uniform cyclic loadings. Comparing apparent modulus with the conventional mechanical tensile modulus of Ni nanowire/epoxy composites, the trends were consistent with each other. Ni nanowire/epoxy composites showed the sensing response on humidity and temperature. Self-sensing on applied tensile and compressive loading/unloading was also responded for Ni nanowire/silicone composites via electrical contact resistivity showing the opposite trend between tension and compression. It can be due to the different electrically-interconnecting mechanisms of dispersed Ni nanowires embedded in silicone matrix.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.923-927
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• 2008

본 연구에서는 여주 등 6개 지점에서 유사의 이동이 활발한 시기인 $6{\sim}9$월에 부유사를 측정하여 하천의 유사량 특성을 파악하였다. 측선 배치는 유사채취의 난이도와 채취시간, 하도의 규모 등을 고려하여 등간격의 5개측선수를 적용하였다. 시료분석은 여과법, BW관법, 체분석법으로 수행하여 유사량 산정을 위한 기초자료로 이용하였고, 또한 부유사와 하상토 입경분포 분석 결과로 $Od{\acute{e}}n$ 곡선와 입경가적곡선을 작성하여 대상 지점의 유사특성을 파악하였다. 유량에 따른 총유사량의 관계를 도출하기 위해서 실측된 부유사와 수리량 자료를 이용하였으며, 유사의 거동을 이론적으로 모형화한 간접법으로 총유사량을 추정하였다. 국내 하천의 특성에 적합한 총유사량 추정방법이 아직까지 개발되지 않고 이에 따른 연구 또한 미진한 관계로 기존의 총유사량 산정공식들 중 국내에서 비교적 널리 적용되고 있는 Modified Einstein 공식을 선정하여 대상 지점에 적용하였다. 본 연구에서 선정한 Modified Einstein 공식으로 추정된 총유사량의 적정성을 검토하기 위한 부가적인 수단으로 Engelund&Hansen(1967년), Yang(1973년, 1979년), Ackers&White(1973년) 공식들을 선정하여 Modified Einstein 공식의 추정치와 그 특성을 비교 분석하였다. 그 결과, 일반적으로 모든 지점에서 Modified Einstein 방법으로 추정된 총유사량이 유량에 따라 변동이 크고 상관성이 낮게 분석되었으며, 그 외 3가지 방법으로 추정된 결과는 다소의 변동폭을 가졌으나 대체로 유량의 증가에 따라 유사량도 증가하는 일정한 경향을 나타내었다. 본 연구에서는 각 지점별 유사 유출량과 비유사량을 산정하기 위해서 유량-부유사량관계곡선식과 유량 수문곡선을 이용하였다. 그 결과, 임진강 수계에 위치한 적성 지점에서 가장 크게 산정되었으며, 구례2 지점에서 가장 적은 값을 가졌다. 6개 지점 중 서로 상 하류 관계를 가지는 낙동과 왜관 지점에서 유사량의 특성 변화를 검토한 결과, 상 하류 간의 반전은 저수위 구간을 제외하고는 발생하지 않았으며, 왜관이 낙동 지점보다 큰 값의 유사 유출량을 나타내었다.

• Progress in Medical Physics
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• v.11 no.2
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• pp.109-116
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• 2000

One consideration of radiation delivery in cervical cancer is the complication of critical organs, e.g., bladder and rectum. The absorbed dose of bladder and rectum in HDR intracavitary brachytherapy is measured indirectly with TLD dosimetry A method for the complication reduction of bladder and rectum is suggested. For two-hundred cervical cancer patients, follow-up MRI images were reviewed and distances from cervical central axis to bladder and rectum and vaginal wall thickness were measured. The sealed TLDs were placed upon the gauze packing of the ovoids and the distances to the TLDs from the ovoid center were measured in the simulation film and actual doses of bladder and rectum were calculated. From published data, maximal tolerance doses of bladder and rectum were derived and based on the permissible doses per fraction in HDR brachytherapy the packing thicknesses were determined in both directions. The required minimal packing thicknesses for bladder and rectum were 0.43 and 0.92 cm, respectively. The results were compared with computer calculation using the Meisberger polynomial approach. It is our hope this study can be used for a guideline for users in clinic in estimating critical organ dose in bladder and rectum in HDR brachytherapy in vivo dosimetry.

• Journal of the Korean Geotechnical Society
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• v.24 no.11
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• pp.71-77
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• 2008

In this study, CPT-based methodology for estimating the ultimate lateral resistance, $p_u$, is proposed and verified for lateral loaded piles in sandy soil. Preexistent methods estimating the ultimate lateral resistance, $p_u$, and the ultimate lateral capacity, $H_u$, of pile have been based on the vertical effective stress, relative density, and the coefficient of lateral earth pressure. Similarly, cone resistance $q_c$ in pure sandy soil is expressed by those essential factors. As correlation between $p_u$ and $q_c$ are normalized with average effective stress ${\sigma}_m$, estimation methodology for the lateral loaded pile of $p_u$ in sandy soil is proposed. The method is verified by calibration chamber test results in pure sand. The standard derivation of estimated $p_u$ is 0.279, and COV (Coefficient Of Variation) of estimated $p_u$ is 0.272. These results showed that the estimated pus by the method are analogous with the measured $p_us$ in calibration chamber test.