• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.124-129
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• 1999

In this study, a design method for the flat sound radiator is developed to make new sound radiator system, whose shape is much thinner than that of conventional loudspeaker. Piezofilm (PVDF) is used as actuators of flat sound radiator. To avoid the distortion of sound radiated from flat sound radiator, the frequency response of radiated sound to be flat is taken as the design objective. The electrode pattern and orientation angle of piezofilm actuator is optimized to satisfy the design objective. The formulation is based on the coupled finite element and boundary element method. Genetic algorithm is used in the optimization process, which is useful in the optimization of discrete design variables. Frequency response with optimized piezofilm actuator is made flat enough to satify the design objective. For the enhancement of sound power, double-layered piezofilm actuators are also considered. The sound power with double-layered actuator becomes larger than that with single-layered actuator as expected.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.451-454
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• 2004

We studied on the performance optimized synthesis and mapping of design on to one or more FPGA device. Our multi-phased approach optimized the key parameters that affect performance by adequately modeling the impact on wire length, routability, and performance during technology mapping to produce designs that have high performance and high routability potential.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.4
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• pp.257-261
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• 2011

In this paper, we research the OLSR(Optimized Link State Routing Protocol) of the mobile ad-hoc network protocols, and design the system implementation based on the Embedded Linux for the Ubiquitous Space construction. We prove the performance of proposed system in the various experiment environments through several scenarios which is about transmitting the image data on the mobile ad-hoc network environment.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10a
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• pp.581-583
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• 2000

We are studied on the performance optimized synthesis and mapping of design on to one or more FPGA device. our multi-phased approach optimized the key parameters that affect performance by adequately modeling the impact on wire length, routability, and performance during technology mapping to produce designs that have high performance and high routability potential.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.251-256
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• 1999

In the preliminary design stage of Prestressed Concrete (PSC) Box Girder Bridges, the design factors(including depth, thickness of web, and jacking force) decided by inexperience designer could heavily affect the final design factors. So there is a possibility that the design ends up with an excessively wasteful design. To aim at an economical design with preventing an excessive design, the optimal design program has been developed by using ADS optimal program and SPCFRAME(PSC Bridge analysis program) in these studies. The optimal design program automatically calculates economically optimized design studies. The optimal design program automatically calculates economically optimized design factors by introducing the optimal design techniques of PSC box girder bridge design. The objective function for optimal design is material cost of box girder and constrained functions are constituted with design specifications and workability. The optimal design techniques used the Sequential Unconstraint Minimization Technique (SUMT) with performing the optimal design program. In this study, We designed unprismatic section bridge and prismatic section bridge in the same design condition by optimal design program developed in this study. By analyzing the results we suggested the practical form of tendon's layout comparing the optimal desingns on the basis of each tendon's layout.

• International Journal of Ocean System Engineering
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• v.2 no.4
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• pp.233-238
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• 2012

In this study, we carried out a precedent investigation for an ultra-large container ship, which is expected to be a higher value-added vessel. We studied a preliminary optimized design technique for estimating the principal dimensions of an ultra-large container ship. Above all, we have developed optimized dimension estimation models to reduce the building costs and weight, using previous container ships in shipbuilding yards. We also applied a generalized estimation model to estimate the shipping service costs. A Genetic Algorithm, which utilized the RFR (required freight rate) of a container ship as a fitness value, was used in the optimization technique. We could handle uncertainties in the shipping service environment using a Monte-Carlo simulation. We used several processes to verify the estimated dimensions of an ultra-large container ship. We roughly determined the general arrangement of an ultra-large container ship up to 1500 TEU, the capacity check of loading containers, the weight estimation, and so on. Through these processes, we evaluated the possibility for the practical application of the preliminary design model.

• International Journal of Fluid Machinery and Systems
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• v.5 no.3
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• pp.100-108
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• 2012

Design parameters for suction channels of process centrifugal compressors were investigated, and an optimization method to enhance stage efficiency by using the new design parameters was proposed. From results of computational fluid dynamics, the passage sectional area ratios $A_c/A_e$, $A_e/A_s$ and $A_c/A_s$ were found to be the dominant parameters for the pressure loss and circumferential flow distortion, where $A_c$, $A_e$ and $A_s$ are passage sectional areas for the casing upstream side, casing entrance and impeller eye, respectively. The Base suction channel was optimized using the new design parameters, and the Base and Optimized types were tested. Test results showed that the Optimized suction channel achieved 3.8% higher stage efficiency than the Base suction channel while maintaining the same operating range.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.8
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• pp.813-821
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• 2015

In this paper, we analyzed the problems of a batch-type sterilizer and design a continuous sterilizer to control the temperature deviation. The temperature deviation is analyzed with respect to design parameters such as a nozzle diameter, hole diameter, and nozzle length. The significant temperature parameters are optimized using the response surface methodology. An experimental apparatus is developed using the optimized design parameters. Using a field test, we show that the target temperature is obtained in about 7.3 minutes and the temperature deviation is improved about $0.84^{\circ}C$. The optimized parameters from the test are equal to the analytical parameters.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.1
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• pp.53-58
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• 2016

Various jumping robot platforms have been developed to carry out missions such as rescues, explorations, or inspections of dangerous environments. We suggested a jumping robot platform using energy conversion of the elastic body like the bar of a pole vault, which is the main part in which elastic force occurs. The compliant link was optimized by an optimization method based on Taguchi methodology, and the robot's leaping ability was improved. Among the parameters, the length, width, and thickness of the link were selected as design variables first while the others were fixed. The level of the design variables was settled, and an orthogonal array about its combination was made. In the experiment, dynamic simulations were conducted using the DAFUL program, and response table and sensitivity analyses were performed. We found optimized values through a level average analysis and sensitivity analysis. As a result, the maximum leaping height of the optimized robot increased by more than 6.2% compared to the initial one, and these data will be used to design a new robot.

• Aerospace Engineering and Technology
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• v.9 no.1
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• pp.78-83
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• 2010

In the present paper, a flap was optimized to maximize the lift. A 2-element fowler flap system was utilized for optimization with an initial shape of general aviation airfoil and a flap shape designed by Wentz. Response surface method and Hicks-Henne shape function were implemented for optimization. 2-D Navier-Stokes method was used to solve flow field around aGA(W)-1 airfoil with a fowler flap. Commercial programs including Visual-Doc, Gambit/Tgridand Fluent were used. Upper surface shape and the flap gap were optimized and lift for landing condition was improved considerably. The original and optimized flaps were tested in the KARI's 1-m low speed wind tunnel to examine changes in aerodynamic characteristics. For optimized flap tests, the similar trend to prediction could be seen but stall angle of attack was lower than what was expected. Also, less gap than optimized design delayed stall and produced better lift characteristics. This is believed to be the effect of turbulence model.