• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.131-137
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• 2014

Service Oriented Architecture(SOA) is a flexible structure which does not affect other services even when a specific service is changed. It provides the platform with neutral interfaces independent of any others, where services are loosely coupled in a standard way. While ESB (Enterprise Service Bus) is a key technology for service-oriented architecture, few research and development for ESB has been done. In this paper, we designed and implemented the key components of ESB such as mediation service, message oriented middleware service, operation service, monitoring service, application connection service, and database connection service. The performance evaluation was done by measuring the message processing time for the number of messages with various sizes.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.7
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• pp.354-360
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• 2008

Power-related issues have become important considerations in current generation microprocessor design. One of these issues is that of elevated on-chip temperatures. This has an adverse effect on cooling cost and, if not addressed suitably, on chip reliability. In this paper we investigate the general trade-offs between temporal and spatial hot spot mitigation schemes and thermal time constants, workload variations and microprocessor power distributions. By leveraging spatial and temporal heat slacks, our schemes enable lowering of on-chip unit temperatures by changing the workload in a timely manner with Operating System (OS) and existing hardware support.

• Korean Journal of Construction Engineering and Management
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• v.16 no.4
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• pp.89-97
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• 2015

This paper analyzes the duration of the construction document (CD) phase of 42 large public building projects delivered by the total solution service of Public Procurement Services in Korea from 2009 to 2014. The quality of construction documents significantly affects the quality of construction and facility management. Thus, securing appropriate time for the CD phase during project planning is important for the quality of a project. Currently, the duration of the CD phase is planned based on the construction costs of a project following a notice of the Ministry of Land, Infrastructure and Transport. However, our analysis results showed that the correlation between the actual duration of the CD phase and construction costs is very weak. The actual CD phase takes 1.33-1.79 times longer than the planned duration. The practitioners who were interviewed, were already aware that the correlation between the duration of the CD phase and the construction costs is weak. They identified the complexity of the project, the extent of the design changes, project type, client characteristics, and others as more influential factors on the CD phase than the construction costs. To improve the quality of CDs, a new guideline for determining an adequate CD phase duration should be studied and developed.

• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.135-140
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• 2012

Interior Permanent Magnet Synchronous motors (IPMSM) with concentrated winding are superior to distributed winding in the power density point of view. But it causes huge amount of eddy current losses on the permanent magnet. This paper presents the optimal permanent magnet V-shape on the rotor of an interior permanent magnet synchronous motor to reduce the core losses and improve the performance. Each eddy current loss on permanent magnet has been investigated in detail by using FEM (Finite Element Method) instead of equivalent magnetic circuit network method in order to consider saturation and non-linear magnetic property. Simulation-based design of experiment is also applied to avoid large number of analyses according to each design parameter and consider expected interactions among parameters. Consequently, the optimal design to reduce the core loss on the permanent magnet while maintaining or improving motor performance is proposed by an optimization algorithm using regression equation derived and lastly, it is verified by FEM.

• Computational Structural Engineering
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• v.5 no.3
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• pp.105-112
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• 1992

The design of reactor internals requires the accurate vibration characteristics of each component for subsequent dynamic structural response analysis. For Korean standard nuclear power plant some modifications on the Control Element Assembly shroud from the reference design have been made. Since the shroud is complex in geometry having an array of vertical round tubes and webs in a square grid pattern, and being tied down by preloaded tie rods into position, it is planned to perform a vibration measurement program consisting of both experimental and analytical modal studies upon that component. To determine the proper test conditions, the pre-test analysis has been performed using the general purpose structural analysis program ANSYS. Also the effects of the number of master degrees of freedom, holes in the web and tie-rod preload on the natural frequencies are examined prior to the pre-test analysis. After decision of appropriate finite element model, frequency analysis and harmonic analysis are performed and ideas for the test conditions such as the number of measurement points, their locations, measurement frequency range and the excitation force level are determined.

• Journal of Korea Multimedia Society
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• v.17 no.3
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• pp.393-404
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• 2014

This research proposes a method to draw a number of components for roof frame in 3D datum. It is based on the analysis of the roof curvature and their geometric relationship in the traditional wooden buildings. Correlations between the components that generate a roof surface is defined with functional formula. The design system which automatically generates 3D datum for the components is implemented by reflecting the structural mechanics for them. The suggested system provides a control function to easily draw a traditional house. In this system, the components engaged in forming a roof surface are not only automatically generated but also simply modified according to the user's request. It would improves design efficiency and ensure a various roof surface design. Furthermore it makes possible systematic drawing and standardized industrial processing. Consequently, the proposed method is expected to contribute to the popularization of traditional house constructing.

• Journal of the Korean Geotechnical Society
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• v.33 no.4
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• pp.5-15
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• 2017

Three-hinge failure occurs in a jointed rock slope with a joint set parallel with slope and a conjugate joint set. Limit Equilibrium Method (LEM) and Finite Element Method (FEM) which are commonly used for slope design, are not suitable for evaluating stability against three-hinge failure, and this study performed parametric study to analyze the failure mechanism and to find influence factors causing three-hinge failure using UDEC which is a commercial two-dimensional DEM based numerical program. Numerical analyses were performed for various joint structural conditions and joint properties as well as ground water conditions. It was found that pore water pressure is the main factor triggering the three-hinge failure and the mode of failure depends on friction angle of basal joint and bedding joint set. The results obtained from this study can be used for adequate and economic footwall slope reinforcement design and construction.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.174-179
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• 2002

The cable stayed roof structure of Jeju worldcup stadium is erected with correct prestressed force that is required by the structural engineer who designs this structure. This study evaluated and adapted the erection process of cable, the erection force and the measurement of cable force for Jeju worldcup stadium. The process of erection is required not only to calculate election force but also to check structural stability, post process, construction period and using cranes. Considering the site conditions and technical problems, this study can attain successfully the erection of cable stayed roof structure of Jeju worldcup stadium with allowable errors.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.5
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• pp.366-372
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• 2017

In this paper, the analysis of baluns that are inevitably required to design a differential low noise amplifier, The balun converts a single signal input from the antenna into a differential signal, which serves as an input to the differential amplifier. In addition, it protects the circuit from ESD(Electrostatic Discharge) coming through the antenna and helps with input matching. However, in the case of a passive balun used in general, since the AC signal is transmitted through electromagnetic coupling formed between two metal lines, it not only has loss without gain but also has the greatest influence on the total noise figure of the receiving end. Therefore, the design of a balun in a low-noise amplifier is very important, and it is important to design a balun in consideration of line width, line spacing, winding, radius, and layout symmetry that are necessary. In this paper, the factors to be considered for improving the quality factor of balun are summarized, and the tendency of variation of resistance, inductance, and capacitance of the balun according to design element change is analyzed. Based on the analysis results, it is proved that the design of input balun allows the design of low noise, high gain differential amplifier with gain of 24 dB and noise figure of 2.51 dB.

• Journal of Energy Engineering
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• v.23 no.3
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• pp.116-124
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• 2014

In the plants operated under high temperature condition, piping system load analysis is often performed to prevent accidents caused by thermal deformation and also to locate inspection prioritity points of the piping system. In this study, piping system stress analysis was performed for a pipe system between the reactors in a process plant. The piping system includes typically installed hangers and expansion joints. In order to evaluate the effects of structural components such as hangers and expansion joints, the case for the expansion joint or the hanger under abnormal operation is considered. By comparison anlaysis results of piping system during normal operation and abnormal operation, the role of each pipe components are studied.