• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.1
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• pp.37-43
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• 2010

In this paper, a reliability-based design optimization is developed for the topology design of linear structures using a performance measure approach. Spatial domain is discretized using three dimensional Reissner-Mindlin plate elements and design variable is taken as the material property of each element. A continuum based adjoint variable method is employed for the efficient computation of sensitivity with respect to the design and random variables. The performance measure approach of RBDO is employed to evaluate the probabilistic constraints. The topology optimizationproblem is formulated to have probabilistic displacement constraints. The uncertainties such as material property and external loads are considered. Numerical examples show that the developed topology optimization method could effectively yield a reliable design, comparing with the other methods such as deterministic, safety factor, and worst case approaches.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.43-47
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• 2001

A program to design an axial flow fan, analyze the performance and predict the noise was developed. In order to develop the low noise fan, that program is compulsory. This software is composed of three parts : the geometric design module, the performance analysis module, the fan noise prediction module. In order to analyze the performance, three dimensional vortex panel method is used. The unsteady flow field was analyzed by time-marching free wake method. The unsteady force data is then used in predicting the noise. Farassat's equation is used to predict the noise of fan.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.658-663
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• 2001

In this study, the axial-compressor design and performance/flow analysis program is developed. A mean-line analysis was used to determine optimum arrangement of overall geometry and its off-design performance is predicted by stage-stacking method. Three dimensional blade shape is generated using radial equilibrium equation and vortex methods. Various blade shape is generated and their performance is compared. Finally the quasi-three dimensional flow analysis is applied to investigate the detailed flow phenomena.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.9
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• pp.2413-2422
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• 1994

The effects of compressor design conditions on the off-design performance of a single-shaft gas turbine engine have been studied. Three different geometric design conditions are considered and three different values for the specific mass flow rate at the inlet to the compressor are assumed. For each of nine compressor design, the off-design performance of the gas turbine engine is predicted using the method previously proposed by present authors. Results show that the predicted off-design performances are quite different from each other even though they have the same performance at design point: it means that compressor design conditions should be determined in consideration of the off-design performance of the engine. The specific mass flow rate at the inlet to the compressor is also shown that it might be optimized with respect to the net power of the engine.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.317-324
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• 2006

Performance-based design concept is needed to evaluate the seismic capacity of building. In this study, the method estimating the performance point of the spatial structures based on capacity spectrum method (CSM) is proposed. And for efficient evaluation for the performance point of the spatial structures, the algorithm to convert spatial structural system to ESDOF system is simulated Its efficiency is confirmed by comparing with time history analysis of full model. And dynamic behaviors of spatial structures are examined by using this method. At last, evaluation of structural performance according to variation of stiffness after plastic deformation on the substructures is carried out.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.11
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• pp.1081-1087
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• 2015

This article aims to provide a design method of warning thresholds for active safety systems based on the performance-based approach considering driver behaviors. Both positive and negative consequences of warnings are considered, and the main idea is to choose a warning threshold where the positive consequence is maximized, whereas the negative consequence is minimized. The process of the performance-based approach involves: Defining the operating scenarios; setting the trajectory models, including human characteristics; estimating the alert and nominal trajectories; estimating the performance metrics; generating a performance-metric plot; and determining the alert thresholds. This paper chose a lane-departure warning system as an example to show the usefulness of the performance-based approach. Both human and sensor characteristics were considered in the system design, and this paper provided a quantitative method to include human factors in designing active safety systems.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.379-384
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• 2003

A turbo blower directly driven by a variable-speed BLDC motor was designed and tested to investigate performance characteristics. Computational analysis and performance tests validated the design method for the present turbo blower. Experimental measurements showed that the blower has an enough stability margin. This paper gives an outline of design, computational flow analysis and performance test for aerodynamic performance of the blower

• Earthquakes and Structures
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• v.18 no.2
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• pp.185-199
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• 2020

A computationally-efficient method for multi-criteria optimisation is developed for performance-based seismic design of friction energy dissipation dampers in RC structures. The proposed method is based on the concept of Uniform Distribution of Deformation (UDD), where the slip-load distribution along the height of the structure is gradually modified to satisfy multiple performance targets while minimising the additional loads imposed on existing structural elements and foundation. The efficiency of the method is demonstrated through optimisation of 3, 5, 10, 15 and 20-storey RC frames with friction wall dampers subjected to design representative earthquakes using single and multi-criteria optimisation scenarios. The optimum design solutions are obtained in only a few steps, while they are shown to be independent of the selected initial slip loads and convergence factor. Optimum frames satisfy all predefined design targets and exhibit up to 48% lower imposed loads compared to designs using a previously proposed slip-load distribution. It is also shown that dampers designed with optimum slip load patterns based on a set of spectrum-compatible synthetic earthquakes, on average, provide acceptable design solutions under multiple natural seismic excitations representing the design spectrum.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1007-1014
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• 2015

An optimally designed six-phase induction motor (6PIM) is compared with an initial design induction motor having the same ratings. The Genetic Algorithm (GA) method is used for optimization and multi objective function is considered. Comparison of the optimum design with the initial design reveals that better performance can be obtained by a simple optimization method. Also in this paper each design of 6PIM, is simulated by MAXWELL_2D. The obtained simulation results are compared in order to find the most suitable solution for the specified application, considering the influence of each design upon the motor performance. Construction a 6PIM based on the information obtained from GA method has been done. Quality parameters of the designed motors, such as: efficiency, power losses and power factor measured and optimal design has been evaluated. Laboratory tests have proven the correctness of optimal design.

• International Journal of Highway Engineering
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• v.19 no.2
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• pp.113-126
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• 2017

PURPOSES : This study proposes standards for rural access road pavement section and thickness design considering existing access road construction conditions; the study also proposes a complementary policy that can be used for design convenience. METHODS : Various literature review and case studies had been performed in terms of rural access road section and thickness design, both domestically and internationally, and this was followed by domestic rural access road field surveys. KPRP and KENLAYER were used to analyze the commonalities and predict the remaining life. Data on real cost is used to select an appropriate construction method through economic analysis. RESULTS : The economic efficiency of concrete pavement ($15{\times}15$) was the highest in terms of economic efficiency of performance life and traffic volume. In the case of asphalt pavement, it is considered that the most economical method is to implement micro-surfacing method four times as a preventive maintenance method (once every 10 years and 4.5 years for asphalt concrete pavement and MS construction method, respectively). Repairable asphalt pavement is advantageous for areas where heavy vehicles are expected to pass. In the case of other general areas, it is considered economical to place concrete ($15{\times}15$) pavement. However, as analytical results on its performance life are unavailable, it is to be considered for study in the future. CONCLUSIONS : This study proposed interim design guidelines based on various domestic and international design guidelines and case studies. However, in order to develop the final design criteria applicable to the field, it is necessary to (a) estimate the bearing capacity of the lower level of the pavement at various sites, (b) estimate the daily traffic volume, (c) implement advanced low-cost pavement technologies, and (d) propose maintenance standards and techniques for long-term performance.