• KIEAE Journal
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• v.10 no.5
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• pp.71-76
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• 2010

Recently, the construction and plan of super-tall building is attention link of new town development or urban core regeneration. Super-tall Buildings have many advantages and a lot of affects in urban contexts. Also, construction of super-tall building is will be able to social problem like urban core's decline, loss of openspace, incompatible urban scape, traffic congestion of urban core. But, compares to super-tall buildings affects in urban contexts, there was not extra ordinary study about super-tall building by the urban scale approaches. Therefore, need about study materplan planning of the site which is made to meet super-tall building and urban contexts. There are two main processes in this study. First, to analyze the factors affect to masterplan planning of the super-tall building's site. Through the analyzed factors, classify type of super-tall buildings and identify the type's state. Second, to classify and set the elements of masterplan planning factor in the site. Identify the masterplan planning factor's state by deployment materplan planning factor set the current applied to the constructed super-tall buildings. Through this process, identified the recent trend and providied the basic elements of materplan planning of super-tall building's site.

• Nuclear Engineering and Technology
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• v.51 no.2
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• pp.345-355
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• 2019

Use of the reconstructed fuel assemblies from partially burnt nuclear fuel pins is analyzed. This reutilization option is a potential candidate technique to make better use of the nuclear resources. Standard two step method is used to calculate node i.e. fuel assembly average burnup and then pin by pin ${\eta}$ values are reconstructed to ascertain the residual reactivity in the used fuel pins. Fuel pins with ${\eta}$ > 1:0 are used to reconstruct to-be-reused fuel assemblies. These reconstructed fuel assemblies are burnt during the cycle 3, 4, 5 and 6 of a 1000 MW PWR core by replacing fresh, once burnt and twice burnt fuel assemblies of the reference core configurations. It is concluded that using reconstructed fuel assemblies for the fresh fuel affect dearly on the cycle length (>50 EFPD) when more than 16 fresh fuel assemblies are replaced. However, this loss is less than 20 days if the number of fresh fuel assemblies is less than eight. For the case of replacing twice burned fuel, cycle length could be increased slightly (10 days or so) provided burnt fuel pins from other reactors were also available. Reactor safety parameters, like axial off set (< ${\pm}10%$), Doppler temperature coefficient (<0), moderator temperature coefficient at HFP (<0) are always satisfied. Though, 2D and 3D pin peaking factors are satisfied (<1:55) and (<2:52) respectively, for the cases using eight or less reconstructed fuel assemblies only.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.2960-2973
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• 2022

Since Fukushima nuclear power plant (NPP) accident in 2011, the importance of research on various severe accident phenomena has been emphasized. Particularly, detailed analysis of combustion risk is necessary following the containment damage caused by combustion in the Fukushima accident. Many studies have been conducted to evaluate the risk of local hydrogen concentration increases and flame propagation using computational code. In particular, the potential for combustion by local hydrogen concentration in specific areas within the containment has been emphasized. In this study, the process of flame propagation generated inside a reactor core to containment during a loss of coolant accident (LOCA) was analyzed using MELCOR 2.1 code. Later in the LOCA scenario, it was expected that hydrogen combustion occurred inside the reactor core owing to oxygen inflow through the cold leg break area. The main driving force of the oxygen intrusion is the elevated containment pressure due to the molten corium-concrete interaction. The thermal and mechanical loads caused by the flame threaten the integrity of the containment. Additionally, the containment spray system effectiveness in this situation was evaluated because changes in pressure gradient and concentrations of flammable gases greatly affect the overall behavior of ignition and subsequent containment integrity.

• Structural Engineering and Mechanics
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• v.91 no.5
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• pp.503-516
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• 2024

The present research examines the primary resonance (PR) behaviors of oblique stiffened multilayer functionally graded (OSMFG) shallow shells featuring an FG porous (FGP) core under an external excitation. The research considers two distinct types of FGP cores: one characterized by uniform porosity distribution (UPD) and the other by non-uniform porosity distribution (NPD) along the thickness direction. Furthermore, the study explores two types of shallow shells: one with external oblique stiffeners and one with internal oblique stiffeners, which might have angles that are similar or different from each other. Using the stress function alongside the first-order shear deformation theory (FSDT), the research establishes a nonlinear model for OSMFG shallow shells. The strain-displacement relationships are obtained utilizing FSDT and von-Kármán's geometric assumptions. The Galerkin approach is utilized to discretize the nonlinear governing equations, allowing for the analysis of stiffeners at varied angles. To validate the obtained results, a comparison is made not only with the findings of previous research but also with the response of PR obtained theoretically with the method of multiple scales, using the P-T method. Renowned for its superior accuracy and reliability, the P-T method is deemed an apt selection within this framework. Additionally, the study investigates how differences in material characteristics and stiffener angles affect the system's PR behaviors. The results of this study can be used as standards by engineers and researchers working in this area, and they can offer important information for the design and evaluation of the shell systems under consideration.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.3
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• pp.203-209
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• 2015

In this paper, we conducted a conventional regression and fuzzy regression analysis of the core competencies of construction subcontractors. The study was undertaken to check whether these two types of regression core capabilities affect the rating of construction subcontractor. Conventional regression result showed some effect on the rating of construction subcontractors on which core competencies to management and firm contribution were conducted. With fuzzy regression analysis, on the other hand, the rating of construction subcontractors could see the Min and Conjunction problem which utilize 100% reliability of Min. Max and Conjunction. From the above, the dependent variable of conventional regression could determine the evaluation grade of construction subcontractor. The fuzzy regression analysis shows the estimator of evaluation grade of the construction subcontractor including or corresponding to the fuzzy output data.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.1
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• pp.67-76
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• 2020

Purpose : The purpose of this study was to provide more effective interventions for elderly men with weak core muscles by measuring the thickness of the muscles according to the five core stabilization exercise and comparing the thickness differences in muscles in each posture. Methods : The study selected 29 elderly men aged 65 to 80 years old among outpatient patients at S Medical Center in B city, and measured the muscle thickness by exercise posture once. In order to find out the thickness of the external oblique (EO), internal oblique (IO), and transverse abdominis (TrA) muscles were measured by using rehabilitative ultrasound imaging (RUSI) in five exercise conditions. Results : A significant change in the thickness of the EO muscles in each group was measured by the method of motion, followed by the abdominal crunches (1.67±0.15), the lower body rotations (1.54±0.07). As a result of measuring the thickness of the IO muscles of each group according to the exercise method, the bridge group (1.14±0.22) was the highest, followed by the abdominal drawing group (1.05±0.03). As a result of measuring the thickness of the TrA muscles of each group according to the exercise method, the abdominal crunches (0.98±1.00) were the highest, and the bridge group (0.57±0.05) were higher in order of magnitude. Conclusion : Consequently, the five core stabilization exercises all affect changes in abdominal thickness and are expected to continue to require training studies on muscle posture.

• Steel and Composite Structures
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• v.22 no.1
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• pp.63-77
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• 2016

Top-down construction is a construction technique in which pit excavation and structure construction are conducted simultaneously. Reducing construction time and minimizing noise and vibration which affect neighboring structures, the technique is widely employed in constructing downtown structures. While H-steel columns have been commonly used as core columns, concrete filled steel tube (CFT) columns are at the center of attention because the latter have less axial directionality and greater cross-sectional efficiency than the former. When compared with circular CFT columns, square CFT columns are more easily connected to the floor structure and the area of percussion rotary drilling (PRD) is smaller. For this reason, square CFT columns are used as core columns of concrete encased and filled square (CET) columns in underground floors. However, studies on the structural behavior and concrete stress transfer of CET columns have not been conducted. Since concrete is cast according to construction sequence, checking the stress of concrete inside the core columns and the stress of covering concrete is essential. This paper presents the results of structural tests and analyses conducted to evaluate the usability and safety of CET columns in top-down construction where CFT columns are used as core columns. Parameters in the tests are loading condition, concrete strength and covering depth. The compressive load capacity and failure behavior of specimens are evaluated. In addition, 2 cases of field application of CET columns in underground floors are analyzed.

• Steel and Composite Structures
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• v.44 no.1
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• pp.65-79
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• 2022

The main goal of this paper is to study the vibration of damaged core laminated annular plates with FG face sheets based on a three-dimensional theory of elasticity. The structures are made of a damaged isotropic core and two external face sheets. These skins are strengthened at the nanoscale level by randomly oriented Carbon nanotubes (CNTs) and are reinforced at the microscale stage by oriented straight fibers. These reinforcing phases are included in a polymer matrix and a three-phase approach based on the Eshelby-Mori-Tanaka scheme and on the Halpin-Tsai approach, which is developed to compute the overall mechanical properties of the composite material. In this study the effect of microcracks on the vibrational characteristic of the sandwich plate is considered. In particular, the structures are made by an isotropic core that undergoes a progressive uniform damage, which is modeled as a decay of the mechanical properties expressed in terms of engineering constants. These defects are uniformly distributed and affect the central layer of the plates independently from the direction, this phenomenon is known as "isotropic damage" and it is fully described by a scalar parameter. Three complicated equations of motion for the sectorial plates under consideration are semi-analytically solved by using 2-D differential quadrature method. Using the 2-D differential quadrature method in the r- and z-directions, allows one to deal with sandwich annular plate with arbitrary thickness distribution of material properties and also to implement the effects of different boundary conditions of the structure efficiently and in an exact manner. The fast rate of convergence and accuracy of the method are investigated through the different solved examples. The sandwich annular plate is assumed to have any arbitrary boundary conditions at the circular edges including simply supported, clamped and, free. Several parametric analyses are carried out to investigate the mechanical behavior of these multi-layered structures depending on the damage features, through-the-thickness distribution, and boundary conditions.

• Composites Research
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• v.20 no.5
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• pp.26-33
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• 2007

Pull-out and shear strengths of insert Joints of sandwich structure were investigated by experiment. Specimens were prepared by cocuring of nomex honeycomb core and carbon-epoxy composite face using an adhesive FM73. A total of 75 specimens with 10 different types depending on the core height and density, face thickness, and loading direction were tested. In the test under pull-out loading, although both the core height and density affect the failure loads, the effect of cell density is more serious. Dominant factor fur failure loads of the joints under shear loading is face thickness and the effect of core height is negligible. In the joint with same dimension, failure loads vary depending on the potted area of the core, particularly in the pull-out test.

• Journal of the Ergonomics Society of Korea
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• v.36 no.2
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• pp.87-108
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• 2017

Objective: The purpose of this study was to precede the acceptance study based on automation steps and user experience that was lacked in the past study on the core technology of autonomous vehicle, ADAS. The first objective was to construct the acceptance model of ADAS technology that is the core technology, and draw factors that affect behavioral intention through user experience-based evaluation by applying driving simulator. The second one was to see the change of factors on automation step of autonomous vehicle through the UX/UA score. Background: The number of vehicles with the introduction of ADAS is increasing, and it caused change of interaction between vehicle and driver as automation is being developed on the particular drive factor. For this reason, it is becoming important to study the technology acceptance on how driver can actively accept giving up some parts of automated drive operation and handing over the authority to vehicle. Method: We organized the study model and items through literature investigation and the scenario according to the 4 stages of automation of autonomous vehicle, and preceded acceptance assessment using driving simulator. Total 68 men and woman were participated in this experiment. Results: We drew results of Performance Expectancy (PE), Social Influence (SI), Perceived Safety (PS), Anxiety (AX), Trust (T) and Affective Satisfaction (AS) as the factors that affect Behavioral Intention (BI). Also the drawn factors shows that UX/UA score has a significant difference statistically according to the automation steps of autonomous vehicle, and UX/UA tends to move up until the stage 2 of automation, and at stage 3 it goes down to the lowest level, and it increases a little or stays steady at stage 4. Conclusion and Application: First, we presented the acceptance model of ADAS that is the core technology of autonomous vehicle, and it could be the basis of the future acceptance study of the ADAS technology as it verifies through user experience-based assessment using driving simulator. Second, it could be helpful to the appropriate ADAS development in the future as drawing the change of factors and predicting the acceptance level according to the automation stages of autonomous vehicle through UX/UA score, and it could also grasp and avoid the problem that affect the acceptance level. It is possible to use these study results as tools to test validity of function before ADAS offering company launches the products. Also it will help to prevent the problems that could be caused when applying the autonomous vehicle technology, and to establish technology that is easily acceptable for drivers, so it will improve safety and convenience of drivers.