• Korean Journal of Computational Design and Engineering
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• v.12 no.3
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• pp.209-219
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• 2007

Designing a complex system such as an LCD developing system becomes inefficient when many designers are involved and create their own parts even though they can be used repeatedly in other sections. Thus, this paper proposes a new design process that can maximize the number of common parts in complex system design by organizing the 3D design process. The proposed design process consists of 5 stages: analysis of design intention, definition of initial product structure, definition of skeleton model, sharing design intention with all assembles, control of correlation between components. The proposed design process can maximize common parts in design process, which results in shorter lead time, less production cost, and greater economic benefits.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.1
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• pp.161-168
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• 2001

The use of composite members to improve the compressive strength of steel structure is a common practice these days and its efficiency has already been proved by several researches and experiments. The result of concrete filled circular tubular(CFCT) stub column tests is introduced in this paper. The main parameter of this test is the ratio of diameter to thickness of circular hollow section. From the test results, the effect of concrete filled in steel tube on the ultimate strength, the deformation capacity and initial stiffness are discussed. The purpose of this paper is to investigate the effect of various parameters and evaluate the compressive strength of confined concrete. It would contribute to a better understanding of CFT structure, further laboratory experimentations are needed for better accurate estimation on its effect.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.8
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• pp.762-769
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• 2004

Not only in building design but also in HVAC system design, it is important to ensure an objectivity in schematic design. In the study, the author suggested a method to make a logical decision for quality design factors a(footing the selection of HVAC type in initial design process, and to provide objective design values. Fuzzy theory, one of the theories describing in quantitative way the ambiguous-natured linguistic values, was used to determine the qualitative design factors of linguistic parameter nature. It was found that it has a potential as a method to determine a HVAC type satisfying the required values of qualitative design factors involved in selection of the system type. But this needs further studies to be settled in the selecting of HVAC type.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1189-1194
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• 2000

The purpose of this investigation is to establish which consequence is happen about initial curing concrete's compressive strength of 7days, 28days which changes W/C ratio by the change of vibrating speed and vibrated time. An experimental parameter is fixed 4 degrees of W/C ratio(45%, 50%, 55%, 60%), 3 degrees of vibrated time(3hr, 6hr, 12hr) and different vibrating speed(0.25kine, 0.5kine, 1kine). As the result, compressive strength of 7days was increased when vibrating speed and vibrated time is 1kine, 12h and also compressive strength of 28days was increased when vibrating speed and vibrated time is 0.25kine and 3hr.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.05a
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• pp.108-113
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• 2001

In this paper, the real-time prediction of high temperature creep strength and creep strength and creep life for nickel-based superalloy Udimet 720 (high-temperature and high-pressure gas turbine engine materials) was performed on round-bar type specimens under pure load at the temperatures of 538, 649 and 704$^{\circ}C$. The predictive equation of ISM creep has better reliability than that of LMP and LMP-ISM, and its reliability is getting better for long time creep prediction(10$^3$~10sup/5/ｈ).

• Journal of Ocean Engineering and Technology
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• v.15 no.2
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• pp.53-60
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• 2001

It was confirmed that the life predictive equation by LMP and LMP-ISM are effective only up to 10$^2$hours and can not be used for long times of $10^3~10^5$ hours, but that by ISM can be used for long times creep life prediction with more reliability. The predictive creep life equation of ISM has better reliability than those by LMP and LMP-ISM, and its realizably is getting better for long time creep prediction($10^3~10^5$ h).

• Transactions of The Korea Fluid Power Systems Society
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• v.1 no.4
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• pp.9-14
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• 2004

An estimation technique called the Extended Kalman filter is used to estimate viscous friction, spring initial contraction, and the spring constant on the swash plate of a variable displacement pump. The feasibility of the approach was established using a simulation study. It showed that these parameters could be estimated very accurately in a reliable and independent fashion. A special experimental system was set up to facilitate the measurement of certain states to enhance the Kalman Filtering approach. The aforementioned parameters were estimated and found to be reasonably repeatable for a common operating point. It was very evident that as the operating conditions changed (i.e. temperature) so did the estimated values of certain parameters such as viscous friction. This was believed to be a good verification test for the approach.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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• pp.1903-1910
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• 2012

This paper presents a data based low-order controller design algorithm for a linear time-invariant process with a time delay. The algorithm is composed by combining an identification step based on open loop pulse test with a low-order controller design step to obtain the entire set of controllers achieving multiple performance specifications. The initial information necessary for this algorithm are merely the width and amplitude of a rectangular pulse, a controller of four types (PI, PD, PID, first-order), and design objectives. Various parametric approaches that have been developed are merged in the controller design algorithm. The resulting controller set satisfying the design objectives are displayed on the 2D and 3D graphics and thus it is very easy for us to pick a controller inside the admissible set because we can check the corresponding closed-loop performances visually.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.2
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• pp.195-195
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• 1999

This paper is Proposed a new method to deal with the optimized auto-tuning for the PID controller which is used to the process-control in various fields. First of all, in this method, 1st order delay system with dead time which is modelled from the unit step response of the system is Pade-approximated, then initial values are determined by the Ziegler-Nickels method. So we can find the parameters of PID controller so as to minimize the fuzzy criterion function which includes the maximum overshoot, damping ratio, rising time and settling time. Finally, after studying the parameters of PID controller by Backpropagation of Neural-Network, when we give new K, L, T values to Neural-Network, the optimized parameter of PID controller is found by Neural-Network Program.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.12
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• pp.1017-1023
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• 2007

This study is intended to analyze the effect of thin ink-film thickness around rotating printing roll on the printing quality in the gravure printing process which is used for making electronics circuit like a RFID tag with a conductive ink. The present work numerically estimates the film thickness around rotating roller partially immersed in ink for which the volume of fluid (VOF) method was adopted to figure out the film formation process around rotating roller. Parameter studies were performed to compare the effect of ink properties (viscosity, surface tension), operating condition (roller rotating speed, initial immersed angle) on the film thickness. The result indicates that the film thickness has a strong dependency on the rotating speed, while the surface tension has negligible effect.