• The KIPS Transactions:PartA
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• v.18A no.5
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• pp.215-224
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• 2011

In this paper, a mechanism connecting all weighted migration routes with minimum cost with EGOSST is proposed. Weighted migration routes may be converted to weighted input edges considered as not only traces but also traffics or trip frequencies of moving object on communication lines, roads or railroads. Proposed mechanism can be used in more wide and practical area than mechanisms considering only moving object traces. In our experiments, edge number, maximum weight for input edges, and detail level for grid are used as input parameters. The mechanism made connection cost decrease average 1.07% and 0.43% comparing with the method using weight minimum spanning tree and weight steiner minimum tree respectively. When grid detail level is 0.1 and 0.001, while each execution time for a connecting solution increases average 97.02% and 2843.87% comparing with the method using weight minimum spanning tree, connecting cost decreases 0.86% and 1.13% respectively. This shows that by adjusting grid detail level, proposed mechanism might be well applied to the applications where designer must grant priority to reducing connecting cost or shortening execution time as well as that it can provide good solutions of connecting migration routes with weights.

• Structural Engineering and Mechanics
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• v.63 no.1
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• pp.125-136
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• 2017

This study investigated the performance of a steel column standing on a reinforced concrete footing when it was subjected to collision of an eight-ton single unit truck. Finite element analyses of the structure with different connection schemes were performed using the finite element model of the truck, and the results showed that the behavior of the column subjected to the automobile impact depended largely on the column-footing connection detail. Various reinforcement schemes were investigated to mitigate the damage caused by the car impact. The probability of the model reinforced with a certain scheme to reach a given limit state was obtained by fragility analysis, and the effects of the combined reinforcement methods were investigated based on the equivalent fragility scheme. The analysis results showed that the reinforcement schemes such as increase of the pedestal area, decrease of the pedestal height, and the steel plate jacketing of the pedestal were effective in reducing the damage. As the speed of the automobile increased the contribution of the increase in the number of the anchor bolts and the dowel bars became more important to prevent crushing of the pedestal.

• Journal of Power Electronics
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• v.17 no.2
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• pp.522-532
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• 2017

This paper presents a novel integrated structure for a cascaded distribution static compensator (D-STATCOM) and distribution transformer for medium-voltage reactive power compensation. The cascaded multilevel converter is connected to a system via a group of special designed taps on the primary windings of the Dyn11 connection distribution transformer. The three-phase winding taps are symmetrically arranged and the connection point voltage can be decreased to half of the line-to-line voltage at most. Thus, the voltage stress for the D-STATCOM is reduced and a compromise between the voltage rating and the current rating can be achieved. The spare capacity of the distribution transformer can also be fully used. The working mechanism is explained in detail and a modified control strategy is proposed for reactive power compensation. Finally, both simulation and scaled-down prototype experimental results are provided to verify the feasibility and effectiveness of the proposed connection structure and control strategy.

• Journal of Power Electronics
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• v.19 no.4
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• pp.934-943
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• 2019

A current balance problem exists in multi-phase LLC converters due to the resonant parameter tolerance. This paper presents a current balancing method for interleaved three-phase half bridge LLC converters. This method regulates the phase shift angle of the driving signals between the three phases based on a converter with a floating Y-connection. The floating midpoint voltage has different influences on each phase current and makes the three-phase current balance performance better than midpoint non-floating systems. Phase shift control between modules can further regulate the midpoint voltage. Then three phase current sharing is realized without adding extra components. The current distributions in a midpoint non-floating system and a midpoint floating system are compared. Then the principle and implementation of the proposed control strategy are analyzed in detail. A 3kW prototype is built to verify the validity and feasibility of the proposed method.

• Steel and Composite Structures
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• v.46 no.2
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• pp.237-252
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• 2023

The article describes the development of a novel dissipative bracing connection device (identified by the acronym DRBrC) for concentrically braced frames in steel and composite structures. The origins of the device trace back to the seminal work of Kelly, Skinner and Heine (1972), and, more directly related, to the PIN-INERD device, overcoming some of its limitations and greatly improving the replaceability characteristics. The connection device is composed of a rigid housing, connected to both the brace and the beam-column connection (or just the column), in which the axial force transfer is achieved by four-point bending of a dissipative pin. The experimental validation stages, presented in detail, consisted of a preliminary testing campaign, resulting in successive improvements of the original device design, followed by a systematic parametric testing campaign. That final campaign was devised to study the influence of the constituent materials (S235 and Stainless Steel, for the pin, and S355 and High Strength Steel, for the housing), of the geometry (four-point bending intermediate spans) and of the loading history (constant amplitude or increasing cyclic alternate). The main conclusions point to the most promising DRBrC device configurations, also presenting some suggestions in terms of the replaceability requirements.

• Journal of the Earthquake Engineering Society of Korea
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• v.27 no.1
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• pp.59-68
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• 2023

The column-tree type steel beam-column connections are commonly used in East Asian countries, including Korea. The welding detail between the stub beam and column is similar to the WUF-W connection; thus, it can be expected to have sufficient seismic performance. However, previous experimental studies indicate that premature slip occurs at the friction joints between the stub and link beams. In this study, for the accurate seismic performance evaluation of column-tree type moment connections, a moment-slip model was proposed by investigating the previous test results. As a result, it was found that the initial slip occurred at about 25% of the design slip moment strength, and the amount of slip was about 0.15%. Also, by comparing the analysis results from models with and without the slip element, the influence of slip on the performance of overall beam-column connections was examined. As the panel zone became weaker, the contribution of slip on overall deformation became greater, and the shear demand for the panel zone was reduced.

• Journal of Korean Society of Steel Construction
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• v.27 no.5
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• pp.423-433
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• 2015

A double split tee connection, which is a beam-column moment connection, shows different behavioral characteristics under the influences of the thickness of a T-stub flange, a high-strength bolt gauge distance, and the number and diameter of a high-strength bolt. A double split tee connection is idealized and designed that a flexural moment normally acting on connections can be resisted by a T-stub and a shear force by a shear tap. However, where a double split tee connection is adopted to a low-and medium-rise steel structure, a small-sized beam member can be adopted. Then, a shear tab may not be bolted to the web of a beam. This study was conducted to suggest the details of a connection to secure that a double split tee connection with a geometric shape has a sufficient capacity to resist a shear force. To verify this, this study was conducted to make a three-dimensional nonlinear finite element analysis on a double split tee connection.

• Journal of the Korean Society for Advanced Composite Structures
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• v.5 no.2
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• pp.9-14
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• 2014

Main topics in this study is a new structural detail for connection between H-Steel or SRC column and flat plate slab. We carried out to evaluate the punching shear performance of H-steel or SRC column + RC slab system for vertical load and lateral load. From the test results structural characteristics - yield moment, yield rotation, maximum moment, deformation capabilities ect. - are obtained and evaluated. In this paper as a shear reinforcement for supporting region of plate closed stirrup type and shear band are used, and their test results are compared.

• Steel and Composite Structures
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• v.37 no.3
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• pp.273-289
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• 2020

Due to the unique construction method of modular steel buildings (MSBs) with units prefabricated fully off the site and assembled quickly on the site, the inter-module connection for easy operation and overall performance of the system were key issues. However, it was a lack of relevant research on the system-level performance of MSBs. This study investigated the seismic performance of two-storey modular steel structure with a proposed vertical rotary inter-module connection. Three full-scale quasi-static tests, with and without corrugated steel plate and its combination, were carried out to evaluate and compare their seismic behaviour. The hysteretic performance, skeleton curves, ductile performance, stiffness degradation, energy dissipation capacity, and deformation pattern were clarified. The results showed that good ductility and plastic deformation ability of such modular steel structures. Two lateral-force resistance mechanisms with different layout combinations were also discussed in detail. The corrugated steel plate could significantly improve the lateral stiffness and bearing capacity of the modular steel structure. The cooperative working mechanism of modules and inter-module connections was further analyzed. When the lateral stiffness of upper and lower modular structures was close, limited bending moment transfer may be considered for the inter-module connection. While a large lateral stiffness difference existed initially between the upper and lower structures, an obvious gap occurred at the inter-module connection, and this gap may significantly influence the bending moments transferred by the inter-module connections. Meanwhile, several design recommendations of inter-module connections were also given for the application of MSBs.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2009.04a
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• pp.133-134
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• 2009

This study deals with a mobile terminal without connection to a network-server-program contained detail information of control-point reading ID consisted of latitude and longitude, following directly checking location on a control-point based on RFID.