• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.4
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• pp.231-238
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• 2004

This paper presents the tensile behavior of the stud connection between reinforced concrete(RC) and steel members. Hanger reinforcements are placed around the studs to transfer the tensile and flexural loads to the opposite side of the concrete member. Eight specimens for the tensile tests are tested with variables, which are the arrangement details of hanger reinforcements, the reinforcing bars, and the embedment length of stud. The results of the tensile tests show that hanger reinforcements are effective to increase tensile strength for stud connections. Hangers and reinforcing bars near stud bolts contributed to the reduction of brittle failure. From the evaluation on the tensile strength by previous design guidelines, it was shown that CCD (Concrete Capacity Design) method was more suitable for estimation of test strength.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.159-165
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• 2015

The article presents a parametric study on geometrical design optimization for coupling the joint between a large exhaust air chimney and electromagnetic pulse (EMP) shield for gas turbine electricity generator. We conducted computational fluid dynamics (CFD) simulations on hydraulic diameters of waveguide below cutoff(WBC) ranges 800mm~1025mm, the connection distance ranges 150~450mm, and exhaust gas flow velocities at 15, 20, and 25m/s. The results show that the diameter of main chimney, connection distance, and exhaust gas velocity had impacts on flow stream at the EMP shield. To provide a fully developed stream line at three different flow velocity cases, the WBC diameter and distance of connection should be larger than 1050mm and longer than 300mm, respectively.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.5
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• pp.253-261
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• 2013

In this paper, we study the problem of controlling composite asynchronous sequential machines. The considered asynchronous machine consists of two input/state machines in cascade connection, where the output of the front machine is delivered to the input channel of the rear machine. The objective is to design a corrective controller realizing model matching such that the stable state behavior of the closed-loop system matches that of a reference model. Since the controller receives the state feedback of the rear machine only, there exists uncertainty about the present state of the front machine. We specify the existence condition for a corrective controller given the uncertainty. The design procedure for the proposed controller is described in a case study.

• The Transactions of the Korea Information Processing Society
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• v.3 no.6
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• pp.1515-1521
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• 1996

Object-oriented and distributed processing methods are adopted next -generation telecommunications management architecture. In this paper, we design and implement gradual federation function on connection management system providing connection services to transport network for interworking and encapsulated trader and gateway function for testing interoperability of these service objects between distributed processing environments. These techniques are practically applicable to support interworking between heterogeneous management network systems according to a tendency of integrating telecommunications management systems.

• Steel and Composite Structures
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• v.18 no.5
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• pp.1103-1117
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• 2015

It is known that material properties, connection quality and manufacturing methods are among the important factors directly affecting the behavior of steel connections and hence steel structures. The possible performance differences between a fabricated connection and its computer model may cause critical design problems for steel structures. Achieving a reliable design depends, however, on how accurately the material properties and relevant constitutive models are considered to characterize the behavior of structures. Conventionally, the stress and strain fields in structural steel connections are calculated using the finite elements method with assumed material properties and constitutive models. Because the conventional strain gages allow the measurement of deformation only at one point and direction for specific time duration, it is not possible to determine the general characteristics of stress-strain distributions in connections after the laboratory performance tests. In this study, a new method is introduced to measure displacement distribution of simple steel welded connections under tension tests. The method is based on analyzing digital images of connection specimens taken periodically during the laboratory tension test. By using this method, displacement distribution of steel connections can be calculated with an acceptable precision for the tested connections. Calculated displacements based on the digital image correlation method are compared with those calculated using the finite elements method.

• Korean Institute of Interior Design Journal
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• v.21 no.5
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• pp.355-362
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• 2012

Water Culture Pavilion was constructed as a part of dam construction and Four-major rivers restoration projects, which have the purpose to prevent damage of natural disaster, localized heavy rain and drought, and has several functions; promotion, education and region culture community. Exhibition space in this culture pavilion should have the excellent connection of various media, contents, and exhibition space because of limited space. The purpose of this study is to analyze flows, continuation and connection of exhibit space with the perspectives of the attribute of water and to suggest various content things, technical, spatial types. This study targets Four-major rivers Water Culture Pavilion in Korea and suggests exhibition presentation methods as analyzing contents, media and constituent of exhibition space for each pavilion exhibition. The result of this study is as follows : First, the circulation is common expressed attribute of water in these four water culture pavilion. The reason is that there is a connection between Four-major rivers restoration projects and the physical attribute of water circulating the steps of evaporation, condensation and precipitation. Second, each pavilion presents circulative solid exhibit, circulative background exhibit, circulative reflective exhibit based on circulation. These three types of exhibition is related the floor separation. Third, each pavilion exhibit zone shows the most circulation, solid, background, reflexibility through educational contents and promoting contents by using graphic, video, sound media.

• Structural Engineering and Mechanics
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• v.74 no.3
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• pp.435-443
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• 2020

The objective of this study was to determine the effective compressive strength of a column-slab connection with different compressive strengths between the column and slab concrete. A total of eight column specimens were fabricated, among which four specimens were restrained by slabs while the others did not have any slab, and the test results were compared with current design codes. According to ACI 318, the compressive strength of a column can be used as the effective compressive strength of the column-slab connection in design when the strength ratio of column concrete to slab concrete is less than 1.4. Even in this case, however, this study showed that the effective compressive strength decreased. The specimen with its slab-column connection zone reinforced by steel fibers showed an increased effective compressive strength compared to that of the specimen without the reinforcement, and the interior column specimens restrained with slabs reached the compressive strength of the column.

• Journal of the Korean Society of Safety
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• v.34 no.3
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• pp.50-56
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• 2019

Precast members have relatively good quality because they are manufactured in an environment suitable for quality control. A typical precast method in which pre-fabricated segments are assembled in the field requires a joint. Although the joint is a small part of the member, it greatly affects the behavior and quality of the structural member. In the previous study of this paper, the flexural strength of a joint, which is generally applied to half-depth precast deck systems, was verified to have higher strength than the design requirement. In addition, the proposed joint has been verified to have higher strength by reinforcing the connecting rebar. However, even if the flexural strength of the joints is sufficient, excessive deflection or lack of fatigue performance is likely to cause cracks in the half-depth precast deck system. In this study, the serviceability of the half-deck precast panel specimens with joints was evaluated and the experimental verification was conducted to evaluate the fatigue performance of the joint without connection rebar. As a result, the serviceability such as deflection and crack width was found to be higher than the design requirement in all the specimens. In the fatigue test, the fatigue effect was insignificant even in the absence of connection rebar.

• Coupled systems mechanics
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• v.8 no.2
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• pp.185-197
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• 2019

Considering the increasing use of tubular profiles in civil construction, this paper highlights the study on the behavior of welded connections between square hollow section column and I-beam, with emphasis on the assessment of the joint stiffness. Firstly, a theoretical analysis of the welded joints has been done focusing on prescriptions of the technical literature for the types of geometries mentioned. Then, a numerical analysis of the proposed joints were performed by the finite element method (FEM) with the software ANSYS 16.0. In this study, two models were evaluated for different parameters, such as the thickness of the cross section of the column and the sizes of cross section of the beams. The first model describes a connection in which one beam is connected to the column in a unique bending plane, while the second model describes a connection of two beams to the column in two bending planes. From the numerical results, the bending moment-rotation ($M-{\varphi}$) curve was plotted in order to determine the resistant bending moment and classify each connection according to its rotational capacity. Furthermore, an equation was established with the aim of estimating the rotational stiffness of welded I beam-to-RHS column connections, which can be used during the structure design. The results show that most of the connections are semi-rigid, highlighting the importance of considering the stiffness of the connections in the structure design.

• Steel and Composite Structures
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• v.39 no.2
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• pp.201-213
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• 2021

Currently, there is a lack of research in the design approach to avoid column wall failure in the concrete filled double skin steel tubular (CFDST) column-beam connections. In this paper, a finite element model has been developed and verified by available experimental data to analyze the failure mechanism of CFDST column-beam connections. Various finite element models with different column hollow ratios (χ) were established. The simulation result revealed that with increasing χ the failure mode gradually changed from yielding of end plate, to local failure of the column wall. Detailed parametric analyses were performed to study the failure mechanism of column wall for the CFDST column-beam connection, in which the strength of sandwiched concrete and steel tube and thickness of steel tube were incorporated. An analytical model was proposed to predict the moment resistance of the assembled connection considering the failure of column wall. The simulation results indicate that the proposed analytical model can provided a conservative prediction of the moment resistance. Finally, an upper bound value of χ was recommend to avoid column wall failure for CFDST column-beam connections.