• Structural Engineering and Mechanics
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• v.24 no.4
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• pp.463-478
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• 2006

The design of structural frameworks for buildings is constantly evolving and is dependent on regional issues such as loading and constructability. One of the most promising recent developments for low to medium rise construction in terms of efficiency of construction, robustness and aesthetic appearance utilises concrete-filled steel tubular sections as the columns in a moment-resisting frame. These are coupled to rigid or semi-rigid connections to composite steel-concrete beams. This paper includes the results of a pilot experimental programme leading towards the development of economical, reliable connections that are easily constructed for this type of frame. The connections must provide the requisite strength, stiffness and ductility to suit gravity loading conditions as well as gravity combined with the governing lateral wind or earthquake loading. The aim is to develop connections that are stiffer, less expensive and easier to construct than those in current use. A proposed fabricated T-stub connection is to be used to connect the beam flanges and the column. These T-stubs are connected to the column using "blind bolts" with extensions, allowing installation from the outside of the tube. In general, the use of the extensions results in a dramatic increase in the strength and stiffness of the T-stub to column connection in tension, since the load is shared between membrane action in the tube wall and the anchorage of the bolts through the extensions into the concrete.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.835-841
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• 2011

Wave power generation systems operated in the ocean, has been developed as large power and grid power connection systems in general. However, small wave power generation systems offer operational efficiency for the lighted (navigation aids) buoy. They simply adopts a full-wave rectification for charging battery (direct connection method). In this paper, a wave power controller based on a booster converter is developed by considering a characteristic of the wells turbine. Both direct connection and booster converter power controller is designed and tested to compare the characteristics. Experiments demonstrate that the output of the proposed controller has improved the characteristic of output power, when generator output voltage is low.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.3
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• pp.163-168
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• 2014

In this paper, when photovoltaic systems are connected to distribution system, most effective capacity and location of PV system are studied considering customer interruption costs of power distribution system. The reliability model of PV system considering the duration of sunshine, the model of time-varying load and Roy Billinton test system (bus2 model) are used. To simulate the effects of PV system, various cases are selected; (1) base case which is no connection of PV system to power distribution system when faults are occurred, (2) 3MW case which is 3[MW] connection of PV system (3) 4[MW] case, and (4) 20[MW] case which is 20[MW] connection of PV system to the bus of power distribution system. The capacity limit of connected PV system is settled to 14[MW] for all cases except case 4. The reliability and customer interruption costs for residential, general, industrial, and educational customer is evaluated.

• Journal of the Korean Society for Advanced Composite Structures
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• v.3 no.4
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• pp.27-37
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• 2012

The construction of a moment connection for a rectangular hollow section (RHS) column and a H-shaped beam is difficult because the RHS is a closed section. When a inner diaphragm is used for such a connection, in general, it is installed after cutting the HSS columns, which results in increased construction work. This paper suggests a new fabrication method to overcome such problems: An inner diaphragm is welded to inside a C-shaped section first, and then a column is fabricated by welding two C-shaped sections. This fabrication method is superior to a classic method in terms of constructibility. An experimental and a numerical study using Ansys 9.0 were performed in order to compare the strength of connections with respect to the presence of concrete, the corner shape of diaphragm, and the axis of loading. The experimental results including initial stiffness and ultimate loads are reported and the analytical results including load transfer mechanism, degree of stress concentration, and strain distribution are also reported.

• 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.

• Journal of applied mathematics & informatics
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• v.7 no.1
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• pp.139-159
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• 2000

In this manuscript we study perturbed Newton-like methods for the solution of nonlinear operator equations in a Banach space and their discretized versions in connection with the mesh independence principle. This principle asserts that the behavior of the discretized process is asymptotically the same as that for the original iteration and consequently, the number of steps required by the two processes to converge to within a given tolerance is essentially the same. So far this result has been proved by others using Newton's method for certain classes of boundary value problems and even more generally by considering a Lipschitz uniform discretization. In some of our earlierpapers we extend these results to include Newton-like methods under more general conditions. However, all previous results assume that the iterates can be computed exactly. This is mot true in general. That in why we use perturbed Newton-like methods and even more general conditions. Our results, on the one hand, extend, and on the other hand, make more practical and applicable all previous results.

• Korean Journal of Mathematics
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• v.6 no.2
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• pp.281-289
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• 1998

On a generalized Riemannian manifold $X_n$, we may impose a particular geometric structure by the basic tensor field $g_{\lambda\mu}$ by means of a particular connection ${\Gamma}{_\lambda}{^\nu}_{\mu}$. For example, Einstein's manifold $X_n$ is based on the Einstein's connection defined by the Einstein's equations. Many recurrent connections have been studied by many geometers, such as Datta and Singel, M. Matsumoto, and E.M. Patterson. The purpose of the present paper is to study some relations between a generalized semisymmetric $g$-recurrent manifold $GSX_n$ and its submanifold. All considerations in this present paper deal with the general case $n{\geq}2$ and all possible classes.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.90-92
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• 2005

In this paper, we design a digital protection IED(Intelligent Electric Device) for a distributed power system in connection with power grid. The device can measure various elements for protection and communicate with another devices through network. The protection IED is composed of specific function modules: signal process module which converts analog signal from PT and CT handle algorithm to digital one; communication module for connection with another IEDs; input/output module for user-interfaces; main control module for control the whole modules. A general purpose DSP board with TMS320C2812 is used in the IED. Experiments with the power system simulator DOBLE have been made to verily the proposed hardware system.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.534-541
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• 2004

To boost the Korean peninsula as a logistical hub of North-East Asia in 21st century is an important part of Korean development strategies. This research has been conducted on the premise that the connection and operation of the Korean Peninsula break-railway and Euro-Asian railway network will be a great drive for Korean economy and railway technology development. For the preparation to do a further research on this subject, this paper introduces the general condition and related basic material for the railway network operation through the countries along the corridor. It also provides the basic data of railway and actual operation condition in the involved Euro- Asian areas, such as Russia, China, Mongolia, Kazakh-stan, etc.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.11a
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• pp.450-455
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• 1998

This paper proposes an enhanced transport protocol for multipeer communications. It is assumed that there exists a transport connection owner that takes the roles of the establishment, management and termination of a transport connection. The proposed protocol classifies the data transfer type into simplex, duplex and N-plex multicasts and provides several transport services to support various requirements in group communications. The general operations and reliability controls of each transfer type are different from one another and carried out by a shared control tree. The QoS negotiation is performed during the creation phase. The notification of negotiated values is followed by an acknowledgment procedure for confirmation. The four-way handshake is introduced. After negotiation, such a resource reservation protocol as RSVP can reserve system and network resources according to the arbitrated values. This paper suggests a conceptual model of the transport layer and its protocol behaviors over the IP multicast and RSVP network.