• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.9
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• pp.2225-2233
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• 1994

In order to improve the cutting ability of face mill, a model for optimal cutter shape was developed to minimize resultant cutting force by combing cutting force model and optimal technique. Wear test and surface roughness test for optimized and conventional cutter were performed. The new optimized cutter shows longer tool life of 2.29 times than conventional cutter in light cutting condition and 2.52 times in heavy cutting condition. The surface roughness of workpiece by optimized cutter is improved in heavy cutting condition, but deteriorated in light cutting condition in comparison with conventional cutter. The surface profiles of workpiece were analyzed by Fourier transformation. The distribution of cut lay left on workpiece by optimized cutter is more regular than that by the conventional cutter.

• Journal of Korean Society for Quality Management
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• v.48 no.3
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• pp.463-479
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• 2020

Purpose: The purpose of this study is to evaluate the performance of heating equipments by implementing the extreme environment in which ships navigating the ice zone are exposed and to study and apply the experimental method to infer the optimized design for each factors. Methods: It is required to verify by analysis and experiment how the environment with low temperature and wind speed implemented through the test facility affects the heating walk-way and The optimum design of the heating walk-way in that extreme environment is derived using the Taguchi technique. Results: The results of this study are as follows; It was found the effect on the condition of each factor and derive optimized conditions that satisfy the performance condition of the heating walk-way in extreme use environment. Conclusion: Ships operating in Polar waters require reliable and durable facilities for all environments during sailing.

• Transactions of Materials Processing
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• v.29 no.4
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• pp.218-228
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• 2020

The prediction of final mass and optimized process conditions of injection molded products using Artificial Neural Network (ANN) were demonstrated. The ANN was modeled with 10 input parameters and one output parameter (mass). The input parameters, i.e.; melt temperature, mold temperature, injection speed, packing pressure, packing time, cooling time, back pressure, plastification speed, V/P switchover, and suck back were selected. To generate training data for the ANN model, 77 experiments based on the combination of orthogonal sampling and random sampling were performed. The collected training data were normalized to eliminate scale differences between factors to improve the prediction performance of the ANN model. Grid search and random search method were used to find the optimized hyper-parameter of the ANN model. After the training of ANN model, optimized process conditions that satisfied the target mass of 41.14 g were predicted. The predicted process conditions were verified through actual injection molding experiments. Through the verification, it was found that the average deviation in the optimized conditions was 0.15±0.07 g. This value confirms that our proposed procedure can successfully predict the optimized process conditions for the target mass of injection molded products.

• Nuclear Engineering and Technology
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• v.50 no.6
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• pp.877-885
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• 2018

Various controllers such as proportional-integral-derivative (PID) controllers have been designed and optimized for load-following issues in nuclear reactors. To achieve high performance, gain tuning is of great importance in PID controllers. In this work, gains of a PID controller are optimized for power-level control of a typical pressurized water reactor using particle swarm optimization (PSO) algorithm. The point kinetic is used as a reactor power model. In PSO, the objective (cost) function defined by decision variables including overshoot, settling time, and stabilization time (stability condition) must be minimized (optimized). Stability condition is guaranteed by Lyapunov synthesis. The simulation results demonstrated good stability and high performance of the closed-loop PSO-PID controller to response power demand.

• Journal of Microbiology and Biotechnology
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• v.17 no.1
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• pp.89-95
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• 2007

Improvements in the dissolution of proteins in two-dimensional gel electrophoresis have greatly advanced the ability to analyze the proteomes of microorganisms under a wide variety of physiological conditions. This study examined the effect of various combinations of chaotropic agents, a reducing agent, and a detergent on the dissolution of the Streptomyces peucetius cytosolic proteins. The use of urea alone in a rehydration buffer as a chaotropic agent gave the proteome a higher solubility than any of the urea and thiourea combinations, and produced the highest resolution and clearest background in two-dimensional gel electrophoresis. Two % CHAPS, as a detergent in a rehydration buffer, improved the protein solubility. After examining the effect of several concentrations of reducing agent, 50 mM DTT in a rehydration buffer was found to be an optimal condition for the proteome analysis of Streptomyces. Using this optimized buffer condition, more than 2,000 distinct and differentially expressed soluble proteins could be resolved using two-dimensional gel electrophoresis with a pI ranging from 4-7. Under this optimized condition, 15 novel small proteins with low-level expression, which could not be analyzed under the non-optimized conditions, were identified. Overall, the optimized condition helped produce a better reference gel for Streptomyces peucetius.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.32.5-32
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• 2001

There has been many teleoperation systems handling the micro object. However, the stability problem for these systems has not been mentioned yet. Historically, Lawrence[1] proposed the Transparency-Optimized Architecture and passivity theorem for stability analysis of bilateral teleoperation. He claimed that unless the task(or environment) impedance contains significance inertial behavior, Passivity condition for Transparency-optimized architecture is not satisfied. In this paper we propose one method which satisfies passivity condition for the micro-teleoperation system handling a insignificant inertial object and is based on the structure of Lawrence and Hashtrudi-Zaad[2] and velocity-force scaling.

• Microbiology and Biotechnology Letters
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• v.27 no.2
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• pp.136-144
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• 1999

Since the condition of immobilization must be optimized, it is very important to know whether and on how conditions bacterial cells retain their metabolic activity during immobilization process. A bioluminescence intensity had the maximum value when cell concentrations were between 1.0 and 1.2 measured at O.D660. The strontium alginate was used as an immobilization matrix and two independent factors for immobilization of Photobacterium phosphoreum with strontium alginate were optimized with the response surface methodology(RSM) considering degree of bioluminescence. As a result, the optimum concentration for immobilization was found to be 2.4%(w/w) for sodium alginate and 0.31M for strontium chloride, respectively. A dilution was carried out with 2.5%(w/v) NaCl solution that is an optimum environmental condition for growth of P. phosphoreum. Under the such condition of immobilization, hardness could be predicted as 4.66$\times$104N/$m^2$ and it took different time according to the volume of matrix to be immobilized completely.

• Transactions of Materials Processing
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• v.19 no.2
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• pp.113-119
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• 2010

Hydroforming is the technology that utilizes hydraulic pressure to form tube or sheet materials into desired shapes inside die cavities. Tube hydroforming provides a number of advantages over the conventional stamping process, including fewer secondary operations, weight reduction, assembly simplification, adaptability to forming of complex structural components and improved structural strength. In many case, hydroformed parts have to be structurally joined at some point. Therefore it is useful if the hydroformed automotive parts can be given a localized attachment flange. In this study for the numerical process design FE analysis was performed with DYNAFORM 5.5. Die parting angle and circumferential expansion ratio was optimized. With optimized condition, bulge and hydroforming experiments to form flange were performed. Forming characteristic at various pressure conditions was analyzed and optimized internal pressure condition was evaluated. The results show that flanged parts can be successfully produced by tube hydroforming process.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.213-217
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• 2008

This paper describes an application of centrifugal compressor optimization system, in which the blade profile of impeller is represented with NURBS(Non-Uniform Rational B-Spline) curve. A commercial CFD(Computational Fluid Dynamics) program named NUMECA fine/turbo was used to evaluate the performance of the whole centrifugal compressor flow passage including impeller and diffuser. The whole optimization design system was integrated based on iSIGHT, a commercial integration and optimization software, which provides a direct application of some optimization algorithms. To insure the practicability of optimization, the performance of centrifugal compressor under all condition was concerned during the optimizing process. That means a compositive object function considering the aerodynamic efficiency, pressure ratio and mass flow rate under different work condition was applied by using different weight number for different conditions. Using the optimization method described in this paper, an optimized design of the impeller blade of centrifugal compressor was obtained. Comparing to the original design, optimized design has a better performance not only under the design work condition, but also the off-design work condition including near stall and near choke condition.

• Nuclear Engineering and Technology
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• v.37 no.4
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• pp.395-400
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• 2005

An environmental radon monitoring system, comprising a radon-cup, an etching system, and a track counting system, was constructed. The radon cup is a cylindrical chamber with a radius of 2.2 cm and a height of 3.2 cm in combination with a CR-39 detector. Carbon is impregnated in the bodies of the detector chamber to avoid problem of an electrostatic charge. The optimized etching condition for the CR-39 exposed to a radon environment turned out to be a 6 N NaOH solution at 70^{\circ}$ over a 7hour period. The bulk etch rate under the optimized condition was $1.14{\pm}0.03\;{\mu}m\;h^{-1}$. The diameter of the tracks caused by radon and its progeny were found to be in the range of $10\~25\;{\mu}m$ under the optimized condition. The track images were observed with a track counting system, which consisted of an optical microscope, a color charged couple device (CCD) camera, and an image processor. The calibration factor of this system is obtained to be $0.105{\pm}0.006$ tracks $cm^2$ per Bq $m^{-3}$ d.