• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.1
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• pp.87-93
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• 2006

Inventories, and characteristics such as dimension, fuel rod array, weight, $^{235}U$ enrichment, and discharge burnup of spent nuclear fuel (SNF) generated from existing and planed nuclear power plants based on National 2nd Basic Plan for Electric Power Demand and Supply were investigated and projected to support geological disposal system design. The historical and projected inventory by the end 2057 is expected to be 20,500 and 14,800MTU for PWR and CANDU spent nuclear fuel, respectively. The quantity of SNF with initial $^{235}U$ enrichment of 4.5 wt.% and below was shown to be 96.5% in total. Average burnup of SNF revealed $\sim36$ GWD/MTU and $\sim40$ GWD/MTU for the period of 1994-1999 and 2000-2003, respectively. It is expected that the average burnup of SNF will be $\sim45$ GWD/MTU at the end of 2000's. From the comprehensive study, it was concluded that the imaginary SNF with $16\times16$ Korean Standard Fuel Assembly, cross section of $21.4cm\times21.4cm$, length of 453cm, mass of 672 kg, initial $^{235}U$ enrichment of 4.5 wt.%, discharge burnup of 55 GWD/MTU could cover almost all SNFs to be produced by 2057.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.3
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• pp.191-198
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• 2011

In general, conventional criticality analyses for spent fuel transport/dry storage systems have been performed based on assumption of fresh fuel concerning the potential uncertainties from number density calculation of Transuranic and Fission Products in spent fuel. However, because of economic loss due to the excessive criticality margin, recently the design of transport/dry storage systems with Burnup Credit(BUC) application has been actively developed. The uncertainties in criticality analyses on transport/storage systems with BUC technique show strong dependance upon initial enrichment and burnup rate, whereas those in the conventional criticality evaluation based on fresh fuel assumption do not show such a dependance. In this study, regulatory-required uncertainties of the criticality analyses for BK 26 Cask, which is conceptually designed spent fuel transport cask with BUC corresponding to the limiting circumstances on nuclear power plants in Korea, are evaluated as a function of initial enrichment and burnup rate. Results of this study will be used as basic data for spent fuel loading curve of BK 26 Cask.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.1
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• pp.29-37
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• 2007

A conventional single compartment model cannot simulate reasonably the migration phenomenon of contaminants through unsaturated zone, due to the intrinsic unrealistic assumption of the compartment model that contaminants entering a compartment are immediately and uniformly mixed. Although, a multi-compartments model, in which even physically identical layer is divided into multiple compartments, may be used for explaining the retardation of contaminant mass flux along with increasing number of compartments, its numerical modeling is usually time-consuming and appropriate analytical solutions have not been reported yet. In order to improve the conventional compartment models on contaminant migration through unsaturated zone, a series of analytical solutions for multi-compartments model were derived and a generalized constraint under which the results from multi-compartments model can be simply approximated by single compartment model was proposed. The simplified approximation method was verified by a simple numerical analysis on the constraint under hypothetical conditions. It was also proved that the influent contaminant transfer rate from the bulk unsaturated zone can be generally represented into a time-dependent nominal transfer rate rather than a constant. In addition, the nominal transfer rate turned out to be very sensitive to the contaminant transfer rate between compartments in unsaturated zone, but to be almost insensitive to the transfer rate from contaminated zone. It is expected that the simplified approximation method developed in this study can be used for rapid and reasonable estimation of the migration phenomenon of contaminant through unsaturated zone, instead of time-consuming multi-compartments modeling.

• Archives of design research
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• v.19 no.5 s.67
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• pp.55-64
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• 2006

As digital systems were introduced to automotive design in the mid 1980s, the design process has adopted many digital programs to save time compared to the conventional hand drafting. Digital technology was introduced not only to satisfy the reeds of the global environment, as the number of automobiles exported to many different parts of the world has increased, but also to save time and effort in developing several models of quality automobiles. Therefore, every automotive manufacturer in the world has expanded its virtual reality(VR) studio to establish visualization systems that visualize automobiles in the actual size and a co-operation system that enables simultaneous feedback from all of its design studios around the world. Unlike the existing design reviewing methos, the new improved feedback system is assessed as a reasonable method to evaluates and understand how the automobiles are actually manufactured in simulation. It is especially helpful when advanced products and concept cars require fast results. Other strengths of the new system include shorter development period, cost efficiency, no more manual labor, various designs within a short period of time, and realistic visualization of concepts. Large-scale products, including automobiles, need to be projected in the actual size and high clarity through the Power-wall System and are examined in a virtual space called a Cave. Therefore, it took much time to establish digital infrastructure. An infrastructure would constantly require system improvement and performance enhancement, but it is certain that now is the right time for the take-off to utilizing the strengths of digital design and improve the weaknesses. In this respect, this study provided an understanding of the importance of digital design based on digital reinforcements and examined an effective utilization of digital technology for an efficient development of automobiles in the future.

• Archives of design research
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• v.16 no.2
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• pp.323-334
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• 2003

This study is focused on subjective images that are produced before visualization in the digital information environment and on characteristics of objective, dynamic image expression that specifies the subjective images. In this study, the visual world that works in the action of "see"is expanded into vision of eyes, vision of brain, and vision of camera. Also we have redefined the definitions of image and its materialized image, yeongsang. It is defined that image contains a strong meaning of consciousness and mind, and that yeongsang involves vision in which constantly changing information of light is created and reproduced by physical processes. We made it clear that image expression in the 21 st century is becoming more generalized, simplified, and concentrated, by the digital technology, from existing specific non-real images to "informationalized" non-real images. This means that there exists an intrinsic difference in the expressional form of the modern analog environment and that of the recent digital environment in the area of yeongsang communication. Along with development of technology, image information raises plastic reality through indirect experience in the virtual space by expanding the sensual faculty of human. However, there also is a tendency for humans to rely more on technology instead of utilizing their creative faculty. Image expression by“the digital information environment” in the 21st century will pursue two sides; one is to shift from external expression of the human body in the cyber space to internal expression, and the other is to internalize the image world and make it connected worldwide. Further research is necessary in these fields.ary in these fields.

• Journal of Energy Engineering
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• v.27 no.2
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• pp.14-25
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• 2018

The combined cycle power plant has a cycle of operating the gas turbine with fuel, such as natural gas, and then producing steam using residual heat. The fuel gas is supplied to the gas turbine at a level of 4 to 5 MPa, $200^{\circ}C$ through a compressor and a heat exchanger. In this study, the risk assessment method considering the piping system stress was carried out for safe operation and soundness of the gas fuel supply piping system. The API 580/581 RBI code, which is well known for its risk assessment techniques, is limited to reflect the effect of piping stress on risk. Therefore, the systematic stress of the pipeline is analyzed by using the piping analysis. For the study, the piping system stress analysis was performed using design data of a gas fuel supply piping of a combined cycle power plant. The result of probability of failure evaluated by the API code is compared to the result of stress ratio by piping analysis.

• Journal of Engineering Education Research
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• v.8 no.3
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• pp.57-68
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• 2005

The purpose of this study was to analyze the effect of Engineering computer programming instruction using project learning, to find out the ways to solve some revealed problems, and to improve the instruction. Unlike traditional lecture courses, students are encouraged to cultivate problem solving and teamwork skills through the programming project. In order to examine the effect of project learning, a survey was conducted with 49 students. The questionnaire consisted of 20 items with 5-grade scale each, the contents of which included learning value, workload, skills acquirement, assignment and comment. The SPSS, statistical analysis software was used to get statistics such as ANOVA, correlation and mean, etc. The results of this study showed (1) project learning was more efficient to acquire problem solving and teamwork skills compared with lecture learning, (2) there was significant correlation between self directed learning skill and information collecting skill, (3) cyber education system(i-campus) was helpful for students' self learning. But the results also showed that (4) students did not give high scores on items of the workload or difficulty of assignments. So we can conclude that it is necessary to develop the suitable projects for the capability of students to make the better project learning.

• The Journal of Engineering Geology
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• v.20 no.2
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• pp.169-181
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• 2010

This study aimed at simulating several responses to stresses caused by the ground water level variations around the K-1 oil stockpile. For this simulation, we considered the characteristic hydrogeological condition including the special occurrence of long and thick acidic dyke, which is regarded as the main geological structure dominating the ground water flow system at this study area. We activated twenty-four imaginary wells which are located in northern and southern area around central K-1 site. Each neighboring distance is altogether 300 m and whole distance between K-1 site and remote wells is 1,200 m. Through the modeling, we operated the long-term and continuous pumping tests and finally categorized five zones based on maximum pumping rates for the imaginary wells; zone I within 300 meter distance from K-1 site with a pumping rate of 50 $m^3/day$; zone II between 300 to 600 meter distance from K-1 site with a pumping rate of 75 $m^3/day$; zone III between 600 to 900 meter distance from K-1 site with 150 $m^3/day$; zone IV between 900 to 1,200 meter distance from K-1 site with 300 $m^3/day$; and zone V of acidic dyke area. At zone V, especially because of their possibility of high transmissivity for groundwater flow, it is necessary to control and restrict groundwater discharge.

• Journal of Satellite, Information and Communications
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• v.1 no.2
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• pp.1-7
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• 2006

GOCi (Geostationary Ocean Color Imager) is one of the COMS payloads that KARI is currently developing and scheduled to be in operation from around 2008. Its primary objective is to monitor the Korean coastal water environmental condition. We report the current progress in development of the integrated optical model as one of the key analysis tools for the GOCI in-orbit performance verification. The model includes the Sun as the emitting light source. The curved Earth surface section of 2500 km x 2500 km includingthe Korean peninsular os defined as a Lambertian scattering surface consisted of land and sea surface. From its geostationary orbit, the GOCI optical system observes the reflected light from the surfaces with varying reflectance representing the changes in its environmental conditions. The optical ray tracing technique was used to demonstrate the GOCI in-orbit performances such as red tide detection. The computational concept, simulation results and its implications to the on-going development of GOCI are presented.

• Science of Emotion and Sensibility
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• v.22 no.3
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• pp.77-90
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• 2019

In this study, we investigated which message provider is effective in a virtual reality (VR) environment for individuals with different needs with regard to affect (need for affect [NFA]) and cognition (need for cognition [NFC]). According to Haddock et al (2008), individuals with high NFA were more influenced to change their behavior by the emotional aspects of a message, whereas individuals with high NFC were more influenced by the cognitive aspects of the same message. We hypothesized that individual differences in needs could affect not only receipt of the message but also the acceptability of the message provider. For example, someone with high NFA might accept messages more easily from an acquaintance than from experts. In the VR environment, the appearance of the message provider could be manipulated in a way that makes him or her more familiar to the person receiving the message. Accordingly, in order to promote the effectiveness of message providers in a VR environment according to the individual difference in needs, we measured the level of the preference and self-efficacy according to needs (NFA or NFC), type of message provider (expert, significant other, or other), and VR device (text or VR). Contrary to what we expected, the results showed that there was no matching effect between the needs and the message provider. However, we found that level of preference and self-efficacy were significantly high when a VR device was worn only by participants with high NFA. This result suggests that a VR environment is more suitable for providing health advice to people with high NFA. In addition, the novelty of this study is that we tried to find the tailored message provider on health advice in VR environment and it is in the early stage of the research.