• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1682-1685
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• 2005

System algorithms estimated by deterministic input may occur the error between predicted and actual output. Especially, actual system can't predict the exact outputs due to uncertainty and tolerance of input parameters. A single output to a set of inputs has a limited value without the variation. Hence, we should consider various scatters caused by the load assessment, material characteristics, stress analysis and manufacturing methods in order to perform the robust design or estimate the reliability of structure. The system design with uncertainty should perform the probabilistic structural optimization with the statistical response and the reliability. This method calculated the probability distributions of the characteristics such as stress by combining stress analysis, response surface methodology and Monte-Carlo Method and got the probabilistic sensitivity. The sensitivity of structural response with respect to inconstant design variables was estimated by fracture probability. Therefore, this paper proposed the probabilistic reliability design method for fracture of uncorved freight end beam and the design criteria by fracture probability.

• Journal of the Korean Vacuum Society
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• v.15 no.1
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• pp.1-13
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• 2006

Vacuum laboratory in Korea Research Institute of Standards and Science (KRISS) was opened in 1983 for establishing and disseminating vacuum standard in Korea. The major three systems such as the ultrasonic interferometer manometer (UIM), the static expansion system (SES) and the dynamic expansion system (DES) with orifice and porous plug conductance are developed. In this study, the standard systems from low to ultra-high vacuum, uncertainty analysis by ISO regulation, and key and bilateral comparison results will be described.

• Korean Chemical Engineering Research
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• v.58 no.3
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• pp.424-429
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• 2020

An Energy Storage System (ESS) is recently drawing an increasing attention as an efficient tool to cope with variation in the energy system. In order to take the best utilization of ESS, the inherent variation of energy supply and demand should be properly addressed. This paper is concerned with computing the stochastic capacity of ESS in the face of such variations by way of Monte Carlo simulation. The issue of uncertainty in energy systems will be given further focus. More works are expected to be followed to address the issues in academia and industry.

• The KIPS Transactions:PartB
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• v.19B no.1
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• pp.27-30
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• 2012

One of the most fundamental functions required for an intelligent agent is to estimate its current position based upon uncertain sensor data. In this paper, we explain the implementation of a robot localization system using Particle filters, which are the most effective one of the probabilistic localization methods, and then present the result of experiments for evaluating the performance of our system. Through conducting experiments to compare the effect of the noise-free model with that of the noisy state transition model considering inherent errors of robot actions, we show that it can help improve the performance of the Particle filter localization to apply a state transition model closely approximating the uncertainty of real robot actions.

• Nuclear Engineering and Technology
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• v.52 no.7
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• pp.1471-1480
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• 2020

This research presents a case study on the remediation of a radioactive waste (uranium: U) utilizing a multi-objective fuzzy optimization in an electrocoagulation process for the iron-stainless steel and aluminum-stainless steel anode/cathode systems. The incorporation of the cumulative uncertainty of result, operational cost and energy consumption are essential key elements in determining the feasibility of the developed model equations in satisfying specific maximum contaminant level (MCL) required by stringent environmental regulations worldwide. Pareto-optimal solutions showed that the iron system (0 ㎍/L U: 492 USD/g-U) outperformed the aluminum system (96 ㎍/L U: 747 USD/g-U) in terms of the retained uranium concentration and energy consumption. Thus, the iron system was further carried out in a multi-objective analysis due to its feasibility in satisfying various uranium standard regulatory limits. Based on the 30 ㎍/L MCL, the decision-making process via fuzzy logic showed an overall satisfaction of 6.1% at a treatment time and current density of 101.6 min and 59.9 mA/㎠, respectively. The fuzzy optimal solution reveals the following: uranium concentration - 5 ㎍/L, cumulative uncertainty - 25 ㎍/L, energy consumption - 461.7 kWh/g-U and operational cost based on electricity cost in the United States - 60.0 USD/g-U, South Korea - 55.4 USD/g-U and Finland - 78.5 USD/g-U.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.107-113
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• 2014

The derivation of optimal information from decision table is based on the concept of indiscernibility relation and approximation space in rough set. Because decision table is more likely to be susceptible to the superposition or inconsistency in decision table, the reduction of attributes is a important concept in knowledge representation. While complete subsets of the attribute's domain is considered in algebraic definition, incomplete subsets of the attribute's domain is considered in information-theoretic definition. Therefore there is a marked difference between algebraic and information-theoretic definition. This paper proposes a conditional entropy using rough set as information theoretical measures in order to deduct the optimal information which may contain condition attributes and decision attribute of information system and shows its effectiveness.

• Atmosphere
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• v.25 no.3
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• pp.521-528
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• 2015

In this study star photometry was applied to retrieve aerosol optical thickness (AOT) at night. The star photometry system consisted of small refractor, optical filters, CCD camera, and driving mount and was located in Suwon. The calibration constants were retrieved from the astronomical Langley method but standard deviations of these were more than 10% of the mean values. After the calibration the nighttime AOT was retrieved and cloud-screened in clear six days from 25 Nov. 2014 to 17 Jan. 2015. To estimate the quality of the measurements the nighttime AOT was combined with daytime AOT retrieved from sky-radiometer that was located in Seoul and 17 km away from the star photometry system. In spite of the uncertainty of the calibration constants and the spatial difference of two observation systems, the temporal changes of the nighttime AOT coincided with the daytime. The nighttime ${\AA}ngstr{\ddot{o}}m$ exponent was about 20% lower and more variable than the daytime because of the uncertainty of the calibration constants. If the calibration process is more precise, the combination of star and sun or sky photometry system can monitor the air pollution day and night constantly.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.06a
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• pp.186-186
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• 2009

The characterization strategy of fracture networks are classified into a deterministic or statistical characterization according to the type of required information. A deterministic characterization is most efficient for a sparsely fractured system, while the statistics are sufficient for densely fractured rock. In this study, the ensemble mean and variability of the effective connectivity is systematically analyzed with various density values for different network structures of a power law size distribution. The results of high resolution Monte Carlo analyses show that statistical characteristics can be a necessary information to determine the transport properties of a fracture system when fracture density is greater than a percolation threshold. When the percolation probability (II) approaches unity with increasing fracture density, the effective connectivity of the network can be safely estimated using statistics only (sufficient condition). It is inferred from conditional simulations that deterministic information for main pathways can reduce the uncertainty in estimation of system properties when the network becomes denser. Overall results imply that most pathways need to be identified when II < 0.5 statistics are sufficient when II $\rightarrow$ 1 and statistics are necessary and the identification of main pathways can significantly reduce the uncertainty in estimation of transport properties when 0.5$\ll$1. It is suggested that the proper estimation of the percolation probability of a fracture network is a prerequisite for an appropriate conceptualization and further characterization.

• Korean Journal of Agricultural Science
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• v.47 no.3
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• pp.509-517
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• 2020

Geographic information system (GIS) sewer network data are a fundamental input material for urban inundation modeling, which is important to reduce the increasing damages from urban inundation due to climate change. However, the essential attributes of the data built by a local government are often missing because the purpose of building the data is the maintenance of the sewer system. Inconsistent simplification and supplementation of the sewer network data made by individual researchers may increase the uncertainty of flood simulations and influence the inundation analysis results. Therefore, it is necessary to develop a basic algorithm to convert the GIS-based sewage network data into input data that can be used for inundation simulations in consistent way. In this study, the format of GIS-based sewer network data for a watershed near the Sadang Station in Seoul and the Oncheon River Basin in Busan was investigated, and a missing data supplementing algorithm was developed. The missing data such as diameter, location, elevation of pipes and manholes were assumed following a consistent rule, which was developed referring to government documents, previous studies, and average data. The developed algorithm will contribute to minimizing the uncertainty of sewer network data in an urban inundation analysis by excluding the subjective judgment of individual researchers.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.3
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• pp.127-144
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• 2022

This study attempted to analyze the influence of both internal and external business environment factors on the characteristics of the management accounting system (MAS). For this, external business environment factors were divided into environmental uncertainty and market competition while internal factors were classified into management strategy, organizational structure and advanced manufacturing technology. In addition, the characteristics of the MAS were categorized into information scope, timeliness, integration and aggregation. The study results found the followings: Among business environment factors, environmental uncertainty had a relatively significant effect on the scope, integration and aggregation of information while organizational structure revealed the largest influence on timeliness. However, market competition had no particular effect on the characteristics of the MAS.