• Journal of the Korean Society for Precision Engineering
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• v.23 no.8 s.185
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• pp.127-136
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• 2006

Metallic sandwich plates with inner dimpled shell subject to 3-point bending have been analyzed and then optimized for minimum weight. Inner dimpled shells can be easily fabricated by press or roll with high precision and bonded with same material skin sheets by resistance welding or adhesive bonding. Metallic sandwich plates with inner dimpled shell structure can be optimally designed for minimum weight subject to prescribed combination of bending and transverse shear loads. Fundamental findings for lightweight design are presented through constrained optimization. Failure responses of sandwich plates are predicted and formulated with an assumption of narrow sandwich beam theory. Failure is attributed to four kinds of mechanisms: face yielding, face buckling, dimple buckling and dimple collapse. Optimized shape of inner dimpled shell structure is a hemispherical shell to minimize weight without failure. It is demonstrated that bending stiffness of sandwich plate is 2 or 3 times larger than solid plates with the same strength. Failure mode boundaries and iso-strength lines dependent upon the geometry and yield strain of the material are plotted with respect to geometric parameters on the failure map. Because optimal parameters of maximum strength for given material weight can be selected from the map, analytic solutions for maximum strength are expressed as a function of only material property and proposed strength. These optimal parameters match well with numerical optimal parameters.

• Transactions of Materials Processing
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• v.15 no.4 s.85
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• pp.326-332
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• 2006

Sandwich structures, which are composed of a thick core between two faces, are commonly used in many engineering applications because they combine high stiffness and strength with low weight. Depending on the sheets by a rolling process, which is a more efficient and economical approach compared to other types of processes, has become an increasingly important subject of study. In this paper, we made a roll forming machine which progressive forming possible and force measurement for a roll forming of the sheet metal forming. And we designed a roll molding that arrayed of embossing size 3mm in diameter fabricate micro dimple inner structure plate. We carried out forming experiment such as array change and thickness to sts304 sheet. Ultimately, this research developed inner structure plate of high stiffness.

• Steel and Composite Structures
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• v.16 no.3
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• pp.253-267
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• 2014

Based on the test on a 1/2.5-scaled model of a two-bay and three-story inner frame composed of reinforced concrete beams and lattice steel reinforced concrete (SRC) irregular section columns under low cyclic reversed loading, the failure process and the features of the frame were observed. The subsequence of plastic hinges of the structure, the load-displacement hysteresis loops and the skeleton curve, load bearing capacity, inter-story drift ratio, ductility, energy dissipation and stiffness degradation were analyzed. The results show that the lattice SRC inner frame is a typical strong column-weak beam structure. The hysteresis loops are spindle-shaped, and the stiffness degradation is insignificant. The elastic-plastic inter-story deformation capacity is high. Compared with the reinforced concrete frame with irregular section columns, the ductility and energy dissipation of the structure are better. The conclusions can be referred to for seismic design of this new kind of structure.

• Korean Journal of Mathematics
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• v.28 no.4
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• pp.973-984
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• 2020

This paper is devoted to study the reproducing property on 2-inner product Hilbert spaces. We focus on a new structure to produce reproducing kernel Hilbert and Banach spaces. According to multi variable computing, this structures play the key role in probability, mathematical finance and machine learning.

• Journal of the Korean housing association
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• v.18 no.2
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• pp.11-20
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• 2007

The purpose of this study is to find the apartment Choice and Housing Satisfaction by the Housing Value Segmentation. Survey questionnaires were conducted on 1103 married women from three residential areas in Daegu. Data were analized by SPSS package program. Major findings are the following: Quality oriented type preferred environment oriented and multiple apartment. Safety investment type answered the bases of the information as of sales/model house, real estate office, oral information from relative neighbor. Ostentation negative type is dissatisfied for the present apartment were listed such as inconvenient inner structure and inner space, education environment for children, privacy protection, convenient transportation for the urban area. Convenience educational environment type is dissatisfied for the present apartment were listed such as inconvenient inner structure and inner space, anti sonic materials, education environment for children, privacy protection.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.316-319
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• 2008

The L-bending of inner-structure bonded sandwich sheet metal is examined by using a bending die attached to the material testing machine. The specimen is composed of top and bottom layers and a middle layer of pyramid-core structure and each layer is bonded by brazing. The variables chosen for experiments were clearance between punch and die, location of bend line on the specimen surface and clamping type of specimen during L-bending. Effects of these variables on deformation of specimen around die-corner radius were investigated. It was shown that the irregular shapes of recess are formed in the inner layer of bended parts and they greatly depend on working conditions.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1986.04a
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• pp.9-13
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• 1986

• Nonlinear Functional Analysis and Applications
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• v.29 no.2
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• pp.487-499
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• 2024

The main motivation for this paper is to investigate the fixed point property for nonlinear contraction defined on b-Menger inner product spaces. First, we introduce a b-Menger inner product spaces, then the topological structure is discussed and the probabilistic Pythagorean theorem is given and established. Also we prove the existence and uniqueness of fixed point in these spaces. This result generalizes and improves many previously known results.

• Journal of the Korean Institute of Rural Architecture
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• v.12 no.2
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• pp.67-76
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• 2010

This study examined and analyzed uses, transformations, changes of plane and arrangement, and changes of space structure of housing components with traditional folk houses located at Kyideok village, Hanrim-eup, Jeju, and the results of the study can be summarized as follows. First, the exposure of arrangement of folk houses at Kyideok village, Jeju was evenly distributed to the east, the southeast, the northeast and the west in order and it was little different from the use of sunshine conditions by placing the main room on the south in traditional houses of land areas. Second, the space structure of inner room before transformation was divided into seven types. 3-room type was classified into "Sangbang-centered three-room type" and "nanggan-centered three-room type", 4-room type into "four-room type with inner access to warehouse", "four-room type with outer access to warehouse", "kitchen-divided four-room type", "four-room type with two kitchens", "four- room type with nanggan at the right back". Third, according to types of change in arrangement type, the first is new annex addition to existing inner room, the second is the removal of existing annexes including outer room, the third is the extension of inner room size without new construction of annex, the fourth is new construction of annex with new plane form after removal of existing annex, the fifth is no change in arrangement of inner room, outer room, stable, warehouse, etc. Fourth, transformation of space components led to changes of space structure as well as those of plane form. Changes of space structure were divided into reduction type of circulation to specific factors, negligence type without using increased space factor, and addition type having various circulations through the increase of convenience space.

• Journal of Welding and Joining
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• v.23 no.6
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• pp.49-54
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• 2005

Inner Structured and Bonded(ISB) panel, a kind of metallic sandwich panel, consists of two thin skin plates bonded to a micro-patterned inner structure. Its overall thickness is $1\~3mm$and it has attractive properties such as ultra-lightweight, high efficiency in stiffness-to-weight and strength-to-weight ratio. In many previous studies, resistance welding, brazing and adhesive bonding are studied for joining the panel. However these methods did not consider productivity, but focused on structural characteristics of joined panels, so that the joining process is very complicated and expensive. In this paper, a new joining process with resistance welding is developed. Curved surface electrodes are used to consider the productivity and the stopper is used between electrodes during welding time to maintain the shape of inner structure. Welding time, gap of electrodes and distance between welding points are selected as the process parameters. By measuring the tensile load with respect to the variation of welding time and gap of electrodes, proper welding conditions are studied. Welding time is proper between 1.5-2.5cycle. If welding time is too long, then inner structures are damaged by overheating. Gap of electrode should be shorter than threshold value fur joint strength, when total thickness of inner structure and skin plate is 3.3mm, the threshold distance is 3.0mm.