• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2003.10a
• /
• pp.123-129
• /
• 2003

Drift design using resizing techniques can be a very practical method in drift design of high-rise buildings since it cannot require sensitivity analysis and structural re-analysis. Resizing techniques has used the cross sectional areas as design variable and supposed that displacement participation factors are inversely proportional to structural weights. Efficiency of resizing techniques based on displacement participation factors may depend on proper selection of sectional properties as design variables. In this study, two different drift design methods with the different sectional properties as design variables are presented and applied to a 20-story structure.

• Structural Engineering and Mechanics
• /
• v.11 no.2
• /
• pp.151-170
• /
• 2001

With increasing competition, the engineering industry is in need of optimization of designs that would lead to minimum cost or weight. Recent developments in Genetic Algorithms (GAs) makes it possible to model and obtain optimal solutions in structural design that can be put to use in industry. The main objective of this paper is to illustrate typical applications of GAs to practical design of structural systems such as steel trusses, towers, bridges, reinforced concrete frames, bridge decks, shells and layout planning of buildings. Hence, instead of details of GA process, which can be found in the reported literature, attention is focussed on the description of the various applications and the practical aspects that are considered in Genetic Modeling. The paper highlights scope and future directions for wider applications of GA based methodologies for optimal design in practice.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2005.04a
• /
• pp.375-382
• /
• 2005

In this paper, a practical control method of wind-induced vibration of high-rise buildings is presented in the form of resizing algorithm. In the structural design process for high-rise buildings, the lateral load resisting system for the building is more often determined by serviceability design criteria including wind-induced vibration level. Even though many drift method have been developed in various forms, no practical design method for wind induced vibration has been developed so far. Structural engineers rely upon heuristic or experience in designing wind induced vibration. The performance of the proposed method is evaluated by comparing wind-induced vibration levels estimated both from approximate techniques and wind tunnel test.

• Wind and Structures
• /
• v.5 no.2_3_4
• /
• pp.101-114
• /
• 2002

Both a Finite Volume and a Discrete Vortex technique to solve the unsteady Navier-Stokes equations have been employed to study the air flow around long-span bridge decks. The implementation and calibration of both methods is described alongside a quasi-3D extension added to the DVM solver. Applications to the wind engineering of bridge decks include flow simulations at different angles of attack, calculation of aerodynamic derivatives and fluid-structure interaction analyses. These are being presented and their specific features described. If a numerical method shall be employed in a practical design environment, it is judged not only by its accuracy but also by factors like versatility, computational cost and ease of use. Conclusions are drawn from the analyses to address the question of whether computer simulations can be practical design tools for the wind engineering of bridge decks.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.43 no.2
• /
• pp.251-258
• /
• 1994

To apply the Power MOSFET to the high powerd circuits, the parallel operation of the Power MOSFET must be considered because of their low power rating. This means, in practical applications, design methods for the parallel operations are required. However, it is very difficult to investigate the problem of parallel operations by directly changing the internal parameters of the MOSFET. Thus, in this paper, the effects of internal parameters for the parallel operation are investigated using SPICE program which is often used and known that the program is very reliable. The investigation results show that while the gate resistance and gate capacitances are the parameters which affect to the dynamic switching operations, the drain and source resistances are the parameters which affect to the steady-state current unbalances. Through this investigation, the design methods for the parallel operation of the MOSFET are suggested, which, in turn, contributes to the practical use of Power MOSFETs.

• Steel and Composite Structures
• /
• v.4 no.3
• /
• pp.211-226
• /
• 2004

This paper presents a study on the structural behaviour of modular steel scaffolds through both experimental and numerical investigations. Three one-storey and three two-storey modular steel scaffolds were built and tested to failure in order to examine the structural behaviour of typical modular steel scaffolds. Details of the tests and their test results were presented in this paper. Moreover, an advanced non-linear analysis method was employed to evaluate the load carrying capacities of these scaffolds under different support conditions. Comparisons between the experimental and the numerical results on the structural behaviour of these modular steel scaffolds were also presented. Moreover, the restraining effects of external supports in practical situations were also studied through finite element methods. The predicted load carrying capacities and deformations at failure of these models under partially restrained conditions were found to be close to the experimental results. A codified design method for column buckling with modified slenderness ratios was adopted for practical design of modular steel scaffolds.

• Proceedings of the Korea Society for Simulation Conference
• /
• 2004.05a
• /
• pp.142-147
• /
• 2004

It is very difficult to acquire high-fidelity flight test data for small airplanes such as typical unmanned aerial vehicles because MEMS-type small sensors used in the tests do not present reliable data in general. Besides, it is not practical to conduct expensive flight tests for low-cost small airplanes in order to simulate their flight characteristics. A practical approach to obtain acceptable flight data, including stability and control derivatives and data of weight and balance, is proposed in this study. Aircraft design software such as Darcorp's AAA is used to generate aerodynamic data for small airplanes, and moments of inertia are calculated using CATIA, structural design software. These flight data from simulation software are evaluated subjectively and tailored using simulation flight by experienced pilots, based on the certified procedures in FAA AC 120-45A and 40B, which are used for manned airplane simulators.

• The Journal of Korea Robotics Society
• /
• v.3 no.1
• /
• pp.52-57
• /
• 2008

A completely new flying machine is developed and the details for practical implementation is suggested. The proposed machine contains no moving parts so that it can be operated in noiseless manner. This paper presents some operational principles of the flying machine as well as the overall process of designing the basic ionic flyer model. The validation of the model is checked by experiments of test flights. Also, two conceptual design results for practical implementation are introduced with the derivation of design parameters. The application field is expected to include indoor secrete surveillance as well as ion propulsion.

• Journal of Korean Society for Quality Management
• /
• v.36 no.1
• /
• pp.7-19
• /
• 2008

During the past two decades, a huge amount of research on adaptive control charts has been accomplished. Especially, variable sampling interval (VSI), variable sample size (VSS), and variable sample size and sampling interval (VSSI) charts have been focused by many researchers due to their simplicity and efficiency. On the other hand, the difference among notations, assumptions, methodologies may cause confusions in per forming further studies or practical implementations. This research analyses and compares diverse models so as to provide a unified view on statistical and economical characteristics. As a result, we perform comparative study on economical design models of VSI, VSS, and VSSI charts, respectively, We also present practical guidelines to utilize those adaptive control charts.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.13 no.5
• /
• pp.321-332
• /
• 2001

In this study, a design program for ventilation requirements of a longitudinal raod tunnel were developed and investigated. The control volume method was applied to calculate the local air velocity and the local concentration distribution of pollutants, CO, $NO_x$, soot along the tunnel for various tunnel ventilation system. This program was validated by comparing with the practical design data for the road tunnel ventilation system. The calculation results were in good agreement with the practical design data.