• Advances in concrete construction
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• v.14 no.2
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• pp.79-92
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• 2022

The amount and configuration of transverse reinforcement are known as critical parameters that significantly affect the lateral confinement of concrete, the ductility capacity, and the plastic hinge length of RC columns. Based on test results, this study investigated the effect of the three variables on structural indexes such as neutral axis depth, lateral expansion of concrete, and ductility capacity. Five reinforced concrete column specimens were tested under cyclic flexure and shear while simultaneously subjected to a constant axial load. The columns were reinforced by two types of reinforcing steel: rectangular hoops and spiral type reinforcing bars. The variables in the test program were the shape, diameter, and yield strength of transverse reinforcement. The interactive influence of the amount of transverse reinforcement on the structural indexes was evaluated. Test results showed that when amounts of transverse reinforcement were similar, and yield strength of transverse reinforcement was 600 MPa or less, the neutral axis depth of a column with spiral type reinforcing bars was reduced by 28% compared with that of a column reinforced by existing rectangular hoops at peak strength. While the diagonal elements of spiral-type reinforcing bars significantly contributed to the lateral confinement of concrete, the strain of diagonal elements decreased with increases of their yield strength. It was confirmed that shapes of transverse reinforcement significantly affected the lateral confinement of concrete adjacent to plastic hinges. Transverse reinforcement with a yield strength exceeding 600 MPa, however, increased the neutral axis depth of normal-strength concrete columns at peak strength, resulting in reductions in ductility and energy dissipation capacity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.12
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• pp.3098-3108
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• 1996

This paper proposed two mechanisms of fixed method and new arrival method. They are all interactive meachanisms in that a SCP and the SSPs exchange load information for overload control. These mechanisms using simple algorithm based on the standard ACG, apply differenct call gapping time on each SSP under the fairness scheme when they allocates SCP capacity to competing demends. Also in the mechanisms, priority scheme is implemented. Two mechanisms show the almost same results on the call throughput. Fairness about the probability of rejection is maintained same value on all SSPs. On Priority scheme, new arrival method has better achievement than fixed method.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.1
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• pp.56-69
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• 2021

In this paper, the PV system with a link to the commercial system needs some advantages like small capacity, high power factor, high reliability, low harmonic output, maximum power operation of solar cell, and low cost, etc. as well as the properties of inverter. To transfer the PV energy of photovoltaic power generation system to the system and load, it requires PCS in both directions. The purpose of this paper is to confirm the stable power supply through the load leveling by presenting the PCS considering ESS of photovoltaic power generation. In order to achieve these purpose, 5 step process of operation mode algorithm were used according to the solar insolation amount and load capacity and the controller for charging/ discharging control was designed. For bidirectional and effective energy transfer, the bidirectional converter and battery at DC-link stage were connected and the DC-link voltage and inverter output voltage through the interactive inverter were controlled. In order to prove the validity of the suggested system, the simulation using PSIM was performed and were reviewed for its validity and stability. The 3[kW] PCS was manufactured and its test was conducted in order to check this situation. In addition, the system characteristics suggested through the test results was verified and the PCS system presented in this study was excellent and stronger than that of before system.

• Journal of the Korean Society for Precision Engineering
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• v.7 no.3
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• pp.26-36
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• 1990

This paper describes the Computer Aided Design (CAD) of dies for direct hot extrusion of structural shapes such as Z's and U's from aluminum alloys. A simple analysis of the direct extrusion process is developed and used to formulate a disign procedure for determining the optimal shape of the extrusion dies. A computer software system has been developed to design flat-faced dies for non-lubricated hot extrusion process. This software is a system of computer programs which are written to logical design procedure. Computer programs are based on empirical and analytical relationships, as well as on established knowledge based system. In the interactive mode of operation, the reaults at various tages of the design process are plotted on a screen. At any stage, the designer can interact with the computer to change or modify the design, based on his experience. The output from the program is (a) the design of the flat-faced die, (b) information on extrusion load, reduction ratio, and other process variables, etc. The implementation of this CAD system is expected to (a) provide scientific basis and rationalize the die design procedure, (b) optimize extrusion variables to maximize yield and production rate, (c) improve utilization of existing press capacity, etc.

• The Transactions of the Korea Information Processing Society
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• v.4 no.8
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• pp.2080-2091
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• 1997

It is generally recognized that Video On Demand (VOD) service will become a promising interactive service in the emerging broadband integrated services digital networks. A centralized VOD system, all programs are stored in a single VOD server which is linked to each user via exchanges, is applicable when a small number of users enjoys the VOD service. However, in case of large service penetration, it is very important to solve the problems of bandwidth and load concentrating in the central video server(CVS) and program transmission network. In this paper, the architecture of the video distribution service network is studied, then a traffic characteristics and models for VOD system are established, and proposed program allocation method to video servers. For this purpose, we present an analysis of program storage amount in each LVS(Local Video Server), transmission traffic volume between LVSs, and link traffic volume between CVS and LVSs, according to changing the related factors such as demand, the number of LVS, vision probability, etc. A method for finding out storage capacity in LVSs is also presented on the basis of the tradeoffs among program storage cost, link traffic cost, and transmission cost.