• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2578-2590
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• 2023

In this work, a 24-month two-batch fuel management strategy for the APR1400 using LEU + has been investigated, where enrichments of 5.9 and 5.2 w/o are utilized in lieu of the conventional 4-5 w/o UO₂ fuel. In addition, an Accident Tolerant Fuel (ATF) clad based on the swaging technology is applied to APR1400 fuel assemblies. In this special ATF clad design, both outer and inner SS316 layers protect the conventional zircaloy clad. Erbia (Er₂O₃) is introduced as a burnable absorber with two-fold goals to lower the critical boron concentration in the long-cycle LEU + loaded core as well as to handle the LEU + fuel in the existing front-end fuel facilities without renewing the license. Two types of fuel assemblies with different loading of gadolinia (Gd₂O₃) are considered to control both the reactivity and the core radial power distribution. The erbia burnable absorber is uniformly admixed with UO₂ in all fuel pins except for the gadolinia-bearing ones. In this study, two core designs were devised with different erbia loading, and core performance and safety parameters were evaluated for each case in comparison with a core design without any burnable absorbers. The core analysis was done using the two-step method. First, cross-sections are generated by the SERPENT 2 Monte Carlo code, and the 3-D neutronic analysis is performed with an in-house multi-physics nodal code KANT.

• Journal of Technology Innovation
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• v.15 no.2
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• pp.61-81
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• 2007

A typical small firm in consumer goods sectors of developing countries is an OEM supplier to big MNCs. Lacking design and marketing capability, a small firm relies on the MNCs for survival but their long term growth is not guaranteed as the MNCs are always looking for, and ready to relocate to, cheaper production sites. In this light, we can say that there is something like "OEM trap" from which most firms from LDCs find difficult to move out (Lee 2005). In this situation, one way for long term growth and catch-up is to make a transition to the OBM (own brand manufacturer). But, the transition is not easy or even risky. This paper analyzes the cases of three companies in Korea to find out common features in their successful transition to OBM. They are Aurora World (a flush toy maker), Hankook Chinaware (a chinaware maker), and Hanacobi (a plastic-made food container maker with the Lock-and-Lock brand). These firms can be commonly characterized by 1) arranging access to external knowledge base and steady increase of in-house R&D efforts and capabilities leading to acquisition of formal IPRs and their management, and 2) establishment of global production networks with factories in lower-income countries as well as their own independent global marketing network.

• Structural Engineering and Mechanics
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• v.68 no.6
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• pp.721-733
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• 2018

The modal frequency responses of functionally graded (FG) sandwich doubly curved shell panels are investigated using a higher-order finite element formulation. The system of equations of the panel structure derived using Hamilton's principle for the evaluation of natural frequencies. The present shell panel model is discretised using the isoparametric Lagrangian element (nine nodes and nine degrees of freedom per node). An in-house MATLAB code is prepared using higher-order kinematics in association with the finite element scheme for the calculation of modal values. The stability of the opted numerical vibration frequency solutions for the various shell geometries i.e., single and doubly curved FG sandwich structure are proven via the convergence test. Further, close conformance of the finite element frequency solutions for the FG sandwich structures is found when compared with the published theoretical predictions (numerical, analytical and 3D elasticity solutions). Subsequently, appropriate numerical examples are solved pertaining to various design factors (curvature ratio, core-face thickness ratio, aspect ratio, support conditions, power-law index and sandwich symmetry type) those have the significant influence on the free vibration modal data of the FG sandwich curved structure.

• Ocean Systems Engineering
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• v.11 no.4
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• pp.313-330
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• 2021

In this study, the dynamic interaction between an Arctic Spar and drifting level ice is examined in time domain using the newly developed ice-hull-mooring coupled dynamics program. The in-house program, CHARM3D, which is the hull-riser-mooring coupled dynamic simulator is extended by coupling with the open-source discrete element method (DEM) simulator, LIGGGHTS. In the LIGGGHTS module, the parallel-bonding method is implemented to model the level ice using an assembly of multiple bonded spherical particles. As a case study, a spread-moored Artic Spar platform, whose hull surface near waterline is the inverted conical shape, is chosen. To determine the breaking-related DEM parameter (the critical bonding strength), the four-point numerical bending test is used. A series of numerical simulations is systematically performed under the various ice conditions including ice drift velocity, flexural strength, and thickness. Then, the effects of these parameters on the ice force, platform motions, and mooring tensions are discussed. The simulations reveal various features of dynamic interactions between the drifting ice and moored platform for various ice conditions including the novel synchronous resonance at low ice speed. The newly developed simulator is promising and can repeatedly be used for the future design and analysis including ice-floater-mooring coupled dynamics.

• International Journal of Highway Engineering
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• v.14 no.3
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• pp.151-162
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• 2012

It is not surprising to hear news about irresistible natural disasters all over the world due to climate change. Korean Government has focused on developing a variety of green technologies to reduce green house gasses, in particular, carbon dioxide. This study suggested 18 technology divisions for achieving green highway technology development in six different sub-sectors considering life-cycle of roadway and surveyed 29 highway and/or transportation professionals of three institutes using AHP(Analytical Hierarchy Process) analysis to construct "Green Highway"and realize carbon emission reductions and energy use efficiency in a road sector in Korea. Expert Choice Software was used to rank 18 technology divisions weighted by two-level choices. Transport Operating Infrastructure Improvement, Roadway Policy Implementation, Green Transportation(such as Pedestrian and Bicycle) were highly ranked by respondents according to results of the AHP modeling. Among the 18 divisions, technology policy for supporting R&D investments from development to commercialization was ranked as the most significant one to be focused. Green Transportation Facility Design/Construction/Operation and Eco-Friendly Roadway Plan were followed as expected since professionals have thought that the planning/design step of the life-cycle is a starting point to reduce carbon dioxide from roads more and more. Additionally, comparing the results with the Government investment trend 2006-2011 for the roads, it can be interpreted that the Government should invest to the R&D area more widely than before to promote element and core technology development for Green Highway Construction. Above all, small and mid-sized businesses have to be invested as well as encouraged to undertake green highwayrelated objects to accomplish the divisions which ranked high.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2227-2235
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• 2009

This paper describes the system configuration and measured performances of a wireless power transmission system which utilizes microwave. The technically final target of this system is to provide DC power to various mobile terminals within limited spaces such as buildings, conference rooms, and so on. The prototype system is built using in-house designed and fabricated circuits such as microwave oscillator, high power amplifier, microstrip patch antenna, low pass filter, and detector/rectifier. The fixed RF power of 29.3dBm at 2.4GHz is produced from the high power amplifier and transmitted through the transmitting antenna, while the received RF power at the receiving antenna is transformed into DC power through the detector/rectifier. The measured change of DC voltage according to the distance between transmitting and receiving antenna is described.

• Ocean Systems Engineering
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• v.13 no.2
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• pp.173-193
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• 2023

Reliable prediction of the motion of FOWT (floating offshore wind turbine) and associated mooring line tension is important in both design and operation/monitoring processes. In the present study, a 5MW OC4 semisubmersible wind turbine is numerically modeled, simulated, and analyzed by the open-source numerical tool, OpenFAST and in-house numerical tool, Charm3D-FAST. Another commercial-level program FASTv8-OrcaFlex is also introduced for comparison for selected cases. The three simulation programs solve the same turbine-floater-mooring coupled dynamics in time domain while there exist minor differences in the details of the program. Both the motions and mooring-line tensions are calculated and compared with the DeepCWind 1/50 scale model-testing results. The system identification between the numerical and physical models is checked through the static-offset test and free-decay test. Then the system motions and mooring tensions are systematically compared among the simulated results and measured values. Reasonably good agreements between the simulation and measurement are demonstrated for (i) white-noise random waves, (ii) typical random waves, and (iii) typical random waves with steady wind. Based on the comparison between numerical results and experimental data, the relative importance and role of the differences in the numerical methodologies of those three programs can be observed and interpreted. These comparative-study results may provide a certain confidence level and some insight of potential variability in motion and tension predictions for future FOWT designs and applications.

• Korean Institute of Interior Design Journal
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• v.19 no.3
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• pp.30-37
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• 2010

Dutch artist, Theo van Doesburg had shown short but strong experimental aesthetics in his works through De Stijl movement. He played a leading role for editing De Stijl magazine and performed various formative works such as painting, sculpture, and architecture. In 1923 he opened the first De Stijl exhibition cooperated with Cornelis van Eesteren. In this architecture exhibition he showed rich formal spirits of counter-construction in his major design works, that is Maison Particuliere and Maison D'artiste among three houses projects. Formal characteristics of counter-construction can be summed up under two categories, time and space. Analytical results are as follows; First, the characteristics of counter-construction related to time category include two types of two mode. One is linear aspect of time based on the viewer's movement. The other aspect is simultaneity caused by synoptical effect. These could be proved by the analysis of arrangement of color planes. Secondly, the spatial aspects of counter-construction are produced through two different ways of formal strategies. Van Doesburg arranged cubes in very irregular pattern. This treatment induces ambiguous void and creates feeling of subject's space. And, through deleting, shifting, and extending he could make dynamic spatial effect by interpenetration between in and out. This fluid space thus introduces movements of one's gaze and circulation. He denied traditional classical values which had ruled the western aesthetical discipline for centuries and believed that mankind can reach the realm of universal equilibrium by contrast and tension created by counter-construction. In this vein Theo van Doesburg was an avant-garde artist of Hegelian thoughts who adopted the dialectical method without following the formal characteristics from ancestors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.208-216
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• 2019

Rural houses are losing their original shape as they mimic the spatial composition of urban houses. Therefore, the purpose of this study was to extract the design elements needed for rural housing by applying Christopher Alexander's "A PATTERN LANGUAGE" to Standard Rural-House Design (SRHD). The scope and method of research was to compare and analyze the standard designs (SD) produced and distributed by the 'Korea Rural Community Corporation' from 2009 to 2014. The research result is summarized as follows. 1) The housing layout in the SD ignored the site conditions of various rural areas. 2) Most of the houses were not actively planned, considering that they contain various activities of rural life. 3) There was no room for children and the kitchen was planned to integrate the interior into a flexible space in the form of L.D.K. 4) There was no space plan that could be used as both a leasable annex and office space for the farming community. 5) Many small area plans were made because of the SD plan for couples only in 2014. Although the rural environment and living patterns were ignored in the SD, the diverse pattern language provided by the pattern language was developed as a SD element for rural houses, which is the most suitable housing plan for the farmers' livelihood pattern.

• Korean Journal of Construction Engineering and Management
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• v.18 no.3
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• pp.63-73
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• 2017

In contemporary society, it is increasingly common to spend more time indoors. As such, there is a continually growing desire to build comfortable and safe indoor environments. Along with this trend, however, there are some serious indoor-environment challenges, such as the quality of indoor air and Sick House Syndrome. To address these concerns the government implements various systems to supervise and manage indoor environments. For example, green building certification is now compulsory for public buildings. There are three categories of green building certification related to indoor air in Korea: Health-Friendly Housing Construction Standards, Green Standard for Energy & Environmental Design(G-SEED), and Indoor Air Certification. The first two types of certification, Health-Friendly Housing Construction Standards and G-SEED, evaluate data in a drawing plan. In comparison, the Indoor Air Certification evaluates measured data. The certification using data from a drawing requires a considerable amount of time compared to other work. A 2D tool needs to be employed to measure the area manually. Thus, this study proposes an automatic assessment process using a Building Information Modeling(BIM) model based on 3D data. This process, using open source Industry Foundation Classes(IFC), exports data for the certification system, and extracts the data to create an Excel sheet for the certification. This is expected to improve the work process and reduce the workload associated with evaluating indoor air conditions.