• International conference on construction engineering and project management
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• 2013.01a
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• pp.332-337
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• 2013

Various project delivery methods have been utilized by owners over the years to maximize project performance. The design-build delivery method is being increasingly used due to the advantages it can offer to an engineering construction industry. Numerous studies have advocated the use of design/build over the traditional design/bid/build delivery approach. This study represents comprehensive analysis of 40 projects from the construction industry and shows that design/build method may not provide all the benefits to project performance. This study found timesaving was a definitive advantage of design/build project delivery, but the positive effects of cost changes was not convincing. Based on the results of the study, the project management expertise and experience of the contractor may have a greater impact on project performance outcomes than focusing on project delivery strategy only.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.649-654
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• 2001

This paper describes aerodynamic preliminary design performance prediction and flow analysis for centrifugal compressor of the marine middle engine turbocharger. The performance characteristics of turbocharger compressor are investigated at various operating conditions using mass flow rate and revolution speed, and computational flow analysis for impeller and diffuser at design point are performed. Preliminary design results correspond to actual compressor geometric values comparatively by applying modified slip factor. Performance prediction and flow analysis results show good agreement with experiments. Therefore, this will provide the performance prediction in preliminary design, and help to increase the design capability for optimized impeller.

• Journal of the Korea Society for Simulation
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• v.7 no.2
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• pp.1-16
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• 1998

This paper presents an automated methodology for campus network design and performance analysis using the rule-based SES and DEVS modeling & simulation techniques. Proposed methodology for structural design and performance analysis can be utilized not only in the early stage of network design for selecting configurable candidate from all possible design alternatives, but also in simulation verification for generating performance data. Our approach supercedes conventional methodologies in that, first, it can support the configuration automation by utilizing the knowledge of design expert ; second, it can provide the simulation-based performance evaluation ; third, it is established on the basis of the well-formalized framework so that it can support a hierarchical and modular system design. Several simulation tests performed on a campus network example will illustrate our technique.

• International Journal of High-Rise Buildings
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• v.11 no.4
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• pp.363-368
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• 2022

For taller buildings with unconventional architecture, refined structural systems or in geographical areas with high wind conditions, performance-based design can be seen as an enhanced design process and is either a supplement to, or alternative to a prescriptive code-based design. The ultimate goal of Performance-Based Wind Design (PBWD) is to result in a building that better addresses key goals of performance over the buildings full life cycle. Major innovations around the use of a PBWD approach include nonlinear dynamic analysis for wind design, limited inelasticity in the main wind force resisting system elements, and system-based performance criteria. This paper discusses potential considerations and benefits made when using a performance-based approach, in addition to the general practicality of use, for the structural design on a few key tall buildings.

• The KSFM Journal of Fluid Machinery
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• v.20 no.2
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• pp.32-40
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• 2017

In this study, an in-house program to analyze the performance degradation for gas turbines is developed using MATLAB and is validated using commercial software. This program consists of design and off-design calculations. The results of design calculation is used for reference values of off-design calculation. The off-design calculation is composed of measured and expected performance analyses, and turbine inlet temperature correction. In general, performance degradation is analyzed by comparing the results of measured and expected performance analysis. However, if gas turbine performance degrades, turbine inlet temperature might increase due to the general control logic to comply with the power demand. Therefore, it is required to consider the deviation of turbine inlet temperature from the normal value in the performance diagnosis to analyze the performance degradation exactly. In this study, a special effort is given to the correction of turbine inlet temperature. The accuracy of the developed program is confirmed by comparison with commercial software, and its capability of performance diagnosis using the turbine inlet temperature correction is demonstrated.

• Journal of Mechanical Science and Technology
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• v.17 no.11
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• pp.1746-1755
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• 2003

Operating characteristics of a triple pressure reheat HRSG are analyzed using a commercial software package (Gate Cycle by GE Enter Software). The calculation routine determines all the design parameters including configuration and area of each heat exchanger. The off-design calculation part has the capability of simulating the effect of any operating parameters such as power load, process requirements, and operating mode, etc., on the transient performance of the plant. The arrangement of high-temperature and intermediate-temperature components of the HRSG is changed, and its effect on the steam turbine performance and HRSG characteristics is examined. It is shown that there could be a significant difference in HRSG sizes even though thermal performance is not in great deviation. From the viewpoint of both economics and steam turbine performance, it should be carefully reviewed whether the optimum design point could exist. Off-design performance could be one of the main factors in arranging components of the HRSG because power plants operate at various off-design conditions such as ambient temperature and gas turbine load, etc. It is shown that different heat exchanger configurations lead to different performances with ambient temperature, even though they have almost the same performances at design points.

• Steel and Composite Structures
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• v.51 no.2
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• pp.173-183
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• 2024

This study investigates a new seismic retrofit system that utilizes rotational friction dampers and axial springs. The retrofit system involves a steel frame with rotational friction dampers (RFD) at beam-column joints and linear springs at the corners, providing energy dissipation and self-centering capabilities to existing structures. The axial spring acts as a self-centering mechanism that eliminates residual deformations, while the friction damper mitigates seismic damage. To evaluate the seismic performance of the proposed retrofit system, a series of cyclic loading tests were carried out on a steel beam-column subassembly equipped with the proposed devices. An analytical model was then developed to validate the experimental results. A performance point ratio (PPR) was presented to optimize the design parameters of the retrofit system, and a performance-based seismic design strategy was developed based on the PPR. The retrofit system's effectiveness and the presented performance-based design approach were evaluated through case study models, and the analysis results demonstrated that the developed retrofit system and the performance-based design procedure were effective in retrofitting structures for multi-level design objectives.

• The KSFM Journal of Fluid Machinery
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• v.18 no.1
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• pp.20-28
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• 2015

The pump-turbine impeller is the key component of pumped storage power plant. Current design methods of pump-turbine impeller are private and protected from public viewing. Generally, the design proceeds in two steps: the initial hydraulic design and optimization design to achieve a balanced performance between pump mode and turbine mode. In this study, the 3D inverse design method is used for the initial hydraulic impeller design. However, due to the special demand of high performance in both pump and reverse mode, the design method is insufficient. This study is carried out by modifying the geometrical parameters of the blade which have great influence and need special consideration in obtaining the high performance on the both modes, such as blade shape type at low pressure side (inlet of pump mode, outlet of turbine mode) and the blade lean at blade high pressure side (outlet of pump mode, inlet of turbine mode). The influence of the geometrical parameters on the performance characteristic is evaluated by CFD analysis which presents the efficiency and internal flow results. After these investigations of the geometrical parameters, the criteria of designing pump-turbine impeller blade low and high sides shape is achieved.

• Fire Science and Engineering
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• v.24 no.1
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• pp.15-23
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• 2010

Placement method for fire detectors prescribed in current fire safety regulation is just about placing a prescribed number of detectors according to the areas. However, this regulation has no scientific basis and standards from foreign countries are just introduced and fire detectors are installed complying with them. There are two standards in designing fire protection systems; Prescriptive-Based Design that follows stipulated regulations like fire safety standards and Performance-Based Design based on engineering knowledge such as fire dynamics, structural dynamics, mechanics of materials, fluid mechanics, and thermo dynamics. Recently, Fire Protection System Construction Business Act was revised so that fire protection systems can be designed using Performance-Based Design method ('05. 8. 4), though the method has not activated until now. In addition, the enforcement decree defines the range for specific objects of fire protection to which Performance-Based Design is applied ('07, 1. 24). At the moment, by manufacturing simulator so that formulas can be introduced and calculated with software in order to install fire detector of automatic fire detection systems keeping optimized distance, comparing the results with the state of fire detector placed according to Performance-Based Design and analyzing them, this study was intended to settle Performance-Based Design method in the future.

• Earthquakes and Structures
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• v.10 no.2
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• pp.463-482
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• 2016

Air Traffic Control (ATC) towers play significant role in the functionality of each airport. In spite of having complex dynamic behavior and major role in mitigating post-earthquake problems, less attention has been paid to the seismic performance of these structures. Herein, seismic response of an existing ATC tower with a wall-frame structural system that has been designed and detailed according to a local building code was evaluated through the framework of performance-based seismic design. Results of this study indicated that the linear static and dynamic analyses used for the design of this tower were incapable of providing a safety margin for the required seismic performance levels especially when the tower was subjected to strong ground motions. It was concluded that, for seismic design of ATC towers practice engineers should refer to a more sophisticated seismic design approach (e.g., performance-based seismic design) which accounts for inelastic behavior of structural components in order to comply with the higher seismic performance objectives of ATC towers.