• Nuclear Engineering and Technology
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• 제52권9호
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• pp.1917-1925
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• 2020

New versions of ENDF/B and JEFF data libraries have been released during the past two years with significant updates in the neutron reaction sublibrary and the thermal neutron scattering sublibrary. In order to get a more comprehensive impression of the criticality quality of these two latest neutron data libraries, and to provide reference for the selection of the evaluated nuclear data libraries for the science and engineering applications of the Reactor Monte Carlo code RMC, the criticality benchmarking of the two latest neutron data libraries has been performed. RMC was employed as the computational tools, whose processing capability for the continuous representation ENDF/B-VIII.0 thermal neutron scattering laws was developed. The RMC criticality validation suite consisting of 116 benchmarks was established for the benchmarking work. The latest ACE format data libraries of the neutron reaction and the thermal neutron scattering laws for ENDF/B-VIII.0, ENDF/B-VII.1, and JEFF-3.3 were downloaded from the corresponding official sites. The ENDF/B-VII.0 data library was also employed to provide code-to-code validation for RMC. All the calculations for the four different data libraries were performed by using a parallel version of RMC, and all the calculated standard deviations are lower than 30pcm. Comprehensive analyses including the C/E values with uncertainties, the δk/σ values, and the metrics of χ² and < |Δ| >, were conducted and presented. The calculated keff eigenvalues based on the four data libraries generally agree well with the benchmark evaluations for most cases. Among the 116 criticality benchmarks, the numbers of the calculated keff eigenvalues which agree with the benchmark evaluations within 3σ interval (with a confidence level of 99.6%) are 107, 109, 112, and 113 for ENDF/B-VII.0, ENDF/B-VII.1, ENDF/B-VIII.0 and JEFF-3.3, respectively. The present results indicate that the ENDF/B-VIII.0 neutron data library has a better performance on average.

• 한국농공학회논문집
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• 제62권2호
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• pp.39-52
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• 2020

A high quality, long-term, high-resolution precipitation dataset is an essential in climate analyses and global water cycles. Rainfall data from station observations are inadequate over many parts of the world, especially North Korea, due to non-existent observation networks, or limited reporting of gauge observations. As a result, satellite-based rainfall estimates have been used as an alternative as a supplement to station observations. The Climate Hazards Group Infrared Precipitation (CHIRP) and CHIRP combined with station observations (CHIRPS) are recently produced satellite-based rainfall products with relatively high spatial and temporal resolutions and global coverage. CHIRPS is a global precipitation product and is made available at daily to seasonal time scales with a spatial resolution of 0.05° and a 1981 to near real-time period of record. In this study, we analyze the applicability of CHIRPS data on the Korean Peninsula by supplementing the lack of precipitation data of North Korea. We compared the daily precipitation estimates from CHIRPS with 81 rain gauges across Korea using several statistical metrics in the long-term period of 1981-2017. To summarize the results, the CHIRPS product for the Korean Peninsula was shown an acceptable performance when it is used for hydrological applications based on monthly rainfall amounts. Overall, this study concludes that CHIRPS can be a valuable complement to gauge precipitation data for estimating precipitation and climate, hydrological application, for example, drought monitoring in this region.

• 한국경제지리학회지
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• 제16권3호
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• pp.458-471
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• 2013

본 논문은 토지 이용 변화를 예측하는 계량 모형의 정확도 평가에 필수적인 통계량인 성능 지수를 심도 있게 이해하는 것을 목적으로 한다. 이 통계량은 기존의 토지 이용 변화 연구에서 소개된 예측 모형의 정확도를 평가하는 다른 통계량들 (예: 카파 통계량)의 단점을 보완하여 만들어진 것이나, 이 또한 계량 모형의 예측력을 명확하게 평가하고 해석하기에는 제한적이다. 본 논문에서는 성능 지수의 보다 명확한 해석을 위해서 결과물의 공간해상도를 고정해야 함을 밝히고, 그 특정 공간해상도를 "성능 해상도"라 정의한다. 성능 해상도는 예측오류가 현격하게 줄어들면서 계량모형의 예측력이 증가하는 시점의 공간해상도를 일컫는다. 따라서 토지 이용 변화 예측 모형의 예측력을 정확하게 평가하기 위해 두 통계량, 즉 성능 지수와 성능 해상도를 함께 이용할 것을 제안한다.

• Nuclear Engineering and Technology
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• 제39권2호
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• pp.133-142
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• 2007

The Electric Power Research Institute (EPRI) demonstrated a method for monitoring the performance of instrument channels in Topical Report (TR) 104965, 'On-Line Monitoring of Instrument Channel Performance.' This paper presents the results of several models originally developed by EPRI to monitor three nuclear plant sensor sets: Pressurizer Level, Reactor Protection System (RPS) Loop A, and Reactor Coolant System (RCS) Loop A Steam Generator (SG) Level. The sensor sets investigated include one redundant sensor model and two non-redundant sensor models. Each model employs an Auto-Associative Kernel Regression (AAKR) model architecture to predict correct sensor behavior. Performance of each of the developed models is evaluated using four metrics: accuracy, auto-sensitivity, cross-sensitivity, and newly developed Error Uncertainty Limit Monitoring (EULM) detectability. The uncertainty estimate for each model is also calculated through two methods: analytic formulas and Monte Carlo estimation. The uncertainty estimates are verified by calculating confidence interval coverages to assure that 95% of the measured data fall within the confidence intervals. The model performance evaluation identified the Pressurizer Level model as acceptable for on-line monitoring (OLM) implementation. The other two models, RPS Loop A and RCS Loop A SG Level, highlight two common problems that occur in model development and evaluation, namely faulty data and poor signal selection

• 시스템엔지니어링학술지
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• 제6권1호
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• pp.15-23
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• 2010

This paper describes the application method of systems engineering for systems of systems and addressed the evolution in approach as organizations have evolved from standalone platform providers to architect of SoS. There is an increasing need to perform Systems of Systems Engineering(SoSE) in a global environment This has stimulated the development of new, innovative SoSE approaches that surpass current military and industry state-of-the-art systems engineering processes. The simple scaling of the former process was ineffective in dealing with global distributed large-scale integration efforts of network-centric systems of systems. A new SoSE process has been developed which is a significant breakthrough in the development of large complex systems and net-centric systems of systems. The SoSE process provides a complete, detailed and systematic development approach for military and civil SoS. In this point of view, this paper analyzes functionally the architecture framework, process and integrated verification & validation of SoSE. From results of this analysis, perspectives on the application of SoSE suitable for Korea aquisition environment are presented.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권4호
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• pp.272-279
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• 2016

Purpose: In order to fulfill the RAMS (Reliability Availability Maintainability and Safety) requirements in Korean railway systems, specific target metrics should be measured and met the requirements when ordering a new system. This paper presents a procedure to predict and demonstrate the availability, maintainability and safety of subway elevators, escalators and PSD (platform screen doors) systems. Methods: The system manufacturer predicts availability and maintainability with lab and field tested data. After installation, availability and maintainability are demonstrated based on the actual operational data. The data was collected from the FRACAS (Failure Report and Corrective Action System). Results: Methods and process of assessing and analyzing the availability, maintainability and safety are presented for elevating services and PSD systems. The data obtained through the actual operation of the equipment is analyzed and maintained to predict the RAMS based on the component and system level failure data acquired. Conclusion: This study presented an application using IEC 62278 and operational data which can be used in the design and development stage to achieve the RAMS target value of the subway elevators, escalators and PSD systems.

• 한국정보처리학회논문지
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• 제6권9호
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• pp.2365-2372
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• 1999

재사용도 측정 모델은 다음 조건을 만족해야 한다. 1) 측정 속성(척도)들과 컴포넌트들을 쉽게 삽입 삭제할 수 있어야 한다. 2) 타당성에 근거하여 컴포넌트들을 정량적으로 평가할 수 있어야 한다. 3) 가정된 지식을 요구하지 않아야 한다. 4) 각 측정 속성들의 중요도를 객관적으로 산출할 수 있어야 한다. 따라서 본 논문에서는 위의 조건들을 만족시킬 수 있는 재사용 컴포넌트들의 재사용도 측정 모델을 제안한다. 제안된 모델은 적합한 측정 인자들을 선택하고, 러프집합을 이용하여 그들의 중요도를 산출한다. 다음으로 컴포넌트의 재사용도를 측정하기 위해서, 퍼지 적분을 이용하여 측정 인자들의 중요도와 측정값을 종합한다. 마지막으로 기능 중심 컴포넌트들에 제안된 모델을 적용하고, 통계적 방법으로 모델의 타당성을 보인다.

• Journal of Information Processing Systems
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• 제1권1호
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• pp.62-69
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• 2005

This paper presents a queuing analysis model of a PC-based software router supporting IPv6-IPv4 translation for residential gateway. The proposed models are M/G/1/K or MMPP-2/G/1/K by arrival process of the software PC router. M/G/1/K is a model of normal traffic and MMPP-2/G/1/K is a model of burst traffic. In M/G/1/K, the arriving process is assumed to be a Poisson process, which is independent and identically distributed. In MMPP-2/G/1/K, the arriving process is assumed to be two-state Markov Modulated Poisson Process (MMPP) which is changed from one state to another state with intensity. The service time distribution is general distribution and the service discipline of the server is processor sharing. Also, the total number of packets that can be processed at one time is limited to K. We obtain performance metrics of PC-based software router for residential gateway such as system sojourn time blocking probability and throughput based on the proposed model. Compared to other models, our model is simpler and it is easier to estimate model parameters. Validation results show that the model estimates the performance of the target system.

• Mass Spectrometry Letters
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• 제10권3호
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• pp.93-101
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• 2019

Algorithms and software for predicting tandem mass spectra have been developed in recent years. In this work, we explore how distinct in silico $MS^2$ spectra are predicted for isomers, i.e. compounds having the same formula and similar molecular structures, to differentiate between them. We used the CFM-ID 2.0/3.0 predictor with regard to (a) test compounds, whose experimental mass spectra had been randomly sampled from the MassBank of North America (MoNA) collection, and to (b) the most widespread isomers of test compounds searched in the PubChem database. In the first validation test, in silico mass spectra constitute a reference library, and library searches are performed for test experimental spectra of "unknowns". The searches led to the true positive rate (TPR) of ($46-48{\pm}10$)%. In the second test, in silico and experimental spectra were interchanged and this resulted in a TPR of ($58{\pm}10$)%. There were no significant differences between results obtained with different metrics of spectral similarity and predictor versions. In a comparison of test compounds vs. their isomers, a statistically significant correlation between mass spectral data and structural features was observed. The TPR values obtained should be regarded as reasonable results for predicting tandem mass spectra of related chemical structures.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 추계학술대회
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• pp.457-460
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• 2014

모바일 기술의 빠른 발전으로 1인 1-스마트폰 시대가 왔다. 스마트폰 앱(Application : App) 또한 이제 없으면 부자연스러운 생활의 일부가 되었다. 현재 모바일 앱에서 가장 많은 사용자 및 커다란 시장 층을 형성하고 있는 것은 모바일 게임, 그 중에서도 모바일 RPG 분야이다. 하지만 모바일 RPG에 기존의 PC용 RPG 품질평가모델을 그대로 적용시킬 경우 정확한 평가 결과가 나올 수 없다. 스마트폰의 특성을 잘 반영한 새로운 모바일 RPG의 품질평가모델에 관한 연구가 필요한 시점이다. 본 연구에서는 소프트웨어품질에 관한 국제 표준인 ISO/IEC 9126을 기반으로 모바일 RPG의 품질평가요소를 도출하였으며 이를 검증하기 위한 매트릭을 재정의하여 새로운 품질평가모델을 제안하였다.