• Transactions on Electrical and Electronic Materials
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• v.12 no.2
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• pp.56-59
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• 2011

The characterization of the chemical mechanical polishing (CMP) process for undensified phophosilicate glass (PSG) film is reported using design of experiments (DOE). DOE has been used by experimenters to understand the relationship between the input variables and responses of interest in a simple and efficient way, and it typically is beneficial for determining the appropriatesize of experiments with multiple process variables and making statistical inferences for the responses of interest. The equipment controllable parameters used to operate the machine consist of the down force of the wafer carrier, pressure on the back side wafer, table and spindle speeds (SS), slurry flow (SF) rate, pad condition, etc. None of these are independent ofeach other and, thus, the interaction between the parameters also needs to be understoodfor improved process characterization in CMP. In this study, we selected the five controllable equipment parameters the most recommendedby process engineers, viz. the down force (DF), back pressure (BP), table speed (TS), SS, and SF, for the characterization of the CMP process with respect to the material removal rate and film uniformity in percentage terms. The polished material is undensified PSG which is widely used for the plananization of multi-layered metal interconnects. By statistical modeling and the analysis of the metrology data acquired from a series of $2^{5-1}$ fractional factorial designs with two center points, we showed that the DF, BP and TS have the greatest effect on both the removal rate and film uniformity, as expected. It is revealed that the film uniformity of the polished PSG film contains two and three-way interactions. Therefore, one can easily infer that process control based on a better understanding of the process is the key to success in current semiconductor manufacturing, in which the size of the wafer is approaching 300 mm and is scheduled to continuously increase up to 450 mm in or slightly after 2012.

• Journal of the Korean Electrochemical Society
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• v.17 no.3
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• pp.193-200
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• 2014

Research on flow channel designs of the separate plates is necessary to improve the PEMFC performance. On concerning the performance improvement of PEMFC, many recent studies have been made on the interdigitated flow channel using forced convection. In this paper, the interdigitated flow channel is similarly applied on the parallel flow channel with a baffle or baffles. Numerical analysis is performed by using a commercial multiphysics program, which is called COMSOL, on the parallel channel with the fully blocked baffle(FBB) and there are three variables, the position of baffle, flow direction and flow velocity. Each power of the variables is resulted from the fixed 0.5V, the voltage from 80 percents of the maximum power. Finally, based on the full factorial designs(FFD), one of the design of experiments(DOE), each factor which has several levels lead to the conclusion. The analysis of the main effects and interactions of the factors is useful to find the most influenced factor to improve the power.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.617-635
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• 2020

The purpose of this study is to discuss how to improve the maneuverability of lifting and diving for underwater vehicle's vertical motion. Therefore, to solve these problems, applied the 3-D numerical simulation, Taguchi's Design of Experiment (DOE), and intelligent parameter design methods, etc. We planned four steps as follows: firstly, we applied the 2-D flow simulation with NACA series, and then through the Taguchi's dynamic method to analyze the sensitivity (β). Secondly, take the data of pitching torque and total resistance from the Taguchi orthogonal array (L9), the ignal-to-noise ratio (SNR), and analysis each factorial contribution by ANOVA. Thirdly, used Radial Basis Function Network (RBFN) method to train the non-linear meta-modeling and found out the best factorial combination by Particle Swarm Optimization (PSO) and Weighted Percentage Reduction of Quality Loss (WPRQL). Finally, the application of the above methods gives the global optimum for multi-quality characteristics and the robust design configuration, including L/D is 9.4:1, the foreplane on the hull (Bow-2), and position of the sail is 0.25 Ls from the bow. The result shows that the total quality is improved by 86.03% in comparison with the original design.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.3
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• pp.423-431
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• 2016

In this study, wing design optimization for long-endurance unmanned aerial vehicles (UAVs) is investigated. The fluid-structure integration (FSI) analysis is carried out to simulate the aeroelastic characteristics of a high-aspect ratio wing for a long-endurance UAV. High-fidelity computational codes, FLUENT and DIAMOND/IPSAP, are employed for the loose coupling FSI optimization. In addition, this optimization procedure is improved by adopting the design of experiment (DOE) and Kriging model. A design optimization tool, PIAnO, integrates with an in-house codes, CAE simulation and an optimization process for generating the wing geometry/computational mesh, transferring information, and finding the optimum solution. The goal of this optimization is to find the best high-aspect ratio wing shape that generates minimum drag at a cruise condition of $C_L=1.0$. The result shows that the optimal wing shape produced 5.95 % less drag compared to the initial wing shape.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.10
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• pp.859-870
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• 2021

KARI (Korea Aerospace Research Institute) is developing a design framework for the concept and preliminary design of eVTOL aircrafts. A low fidelity mission analysis tool was developed for the eVTOL aircrafts of Lift-Tilt Concept, which have tilt propellers and lift propellers, using open source SUAVE package. For its development, a review for the propeller performance analysis functionality was made. To find the trim solution at each mission segment automatically, an algorithm is implemented, using a global optimization technique through parallel processings and DOE(design of experiment). Using the tool, the one seated eVTOL OPPAV(optionally piloted personal air vehicle) was modeled and evaluated, which results were compared with the preliminary design data.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.9
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• pp.955-960
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• 2008

We investigated and estimated at the characteristics of decomposition and mineralization of benomyl using a design of experiment(DOE) based on the general factorial design in an E-beam process, and also the main factors(variables) with benomyl concentration(X$_1$) and E-beam irradiation(X$_2$) which consisted of 5 levels in each factor was set up to estimate the prediction model and the optimization conditions. At frist, the benomyl in all treatment combinations except 17 and 18 trials was almost degraded and the difference in the decomposition of benomyl in the 3 blocks was not significant(p > 0.05, one-way ANOVA). However, the % of benomyl mineralization was 46%(block 1), 36.7%(block 2) and 22%(block 3) and showed the significant difference of the % that between each block(p < 0.05). The linear regression equations of benomyl mineralization in each block were also estimated as followed; block 1(Y$_1$ = 0.024X$_1$ + 34.1(R$^2$ = 0.929)), block 2(Y$_2$ = 0.026X$_2$ + 23.1(R$^2$ = 0.976)) and block 3(Y$_3$ = 0.034X$_3$ + 6.2(R$^2$ = 0.98)). The normality of benomyl mineralization obtained from Anderson-Darling test in all treatment conditions was satisfied(p > 0.05). The results of prediction model and optimization point using the canonical analysis in order to obtain the optimal operation conditions were Y = 39.96 - 9.36X$_1$ + 0.03X$_2$ - 10.67X$_1{^2}$ - 0.001X$_2{^2}$ + 0.011X$_1$X$_2$(R$^2$ = 96.3%, Adjusted R$^2$ = 94.8%) and 57.3% at 0.55 mg/L and 950 Gy, respectively. A Microtox test using V. fischeri showed that the toxicity, expressed as the inhibition(%), was reduced almost completely after an E-beam irradiation, whereas the inhibition(%) for 0.5 mg/L, 1 mg/L and 1.5 mg/L was 10.25%, 20.14% and 26.2% in the initial reactions in the absence of an E-beam illumination.

• Journal of Aerospace System Engineering
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• v.13 no.1
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• pp.29-37
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• 2019

The objective of this study was to investigate the influence of the blade shape on the impeller performance, for design optimizing of the high airflow impeller. First, the quantity, angle, and length of blades, which are considered to have a large influence on the impeller performance, were selected as design variables. Then, 27 cases of impeller shapes were selected according to the design of experiment (DOE). To predict the conduct of the blower based on the selected impeller shape, flow analysis was performed using the immersed solid method of ANSYS CFX. In the CFD results, the highest airflow was expected in the impeller having a combination of 50 EA, $6^{\circ}$ and 5 mm. Finally, a blower with the original impeller shape and the optimized impeller shape was fabricated using a 3D printer, and the analysis tendency and experimental tendency were verified through experiments.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.11
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• pp.1361-1369
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• 2013

This study performs a computational fluid dynamics (CFD) analysis of the inner flow of a multihole injector nozzle by using ANSYS CFX 13.0. Based on the obtained results, a design of experiment (DOE) was performed and applied to investigate the effects of injector nozzle design parameters on cavitation. To analyze the design sensitivity and signal-to-noise ratio (S/N ratio), the hole diameter, hole length, hole angle, and K-factor of the nozzle hole were selected as design parameters, and the effect of these parameters was investigated at 16 experimental points. Consequently, it was found that the effect of the K-factor on the cavitation and inner flow of the injector nozzle is the greatest. Thus, the selection of a suitable K-factor is important in nozzle design considering cavitation flow.

• Applied Chemistry for Engineering
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• v.19 no.2
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• pp.179-184
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• 2008

The separation and purification of succinate are necessary for the succinic acid production by a fermentation process. Among the purification processes, desalination of succinate is inevitable. In this work, electrodialysis was selected as a desalination method and its operating parameters affecting the degree of desalination and energy consumption were examined. Commercialized electrodialysis apparatus was used in this work and its optimum operating parameters were determined by using design of experiment (DOE) method. Voltage, concentration of succinate, and pH were selected as main parameters. Among them, voltage seemed to be the most important one. The final conversion of succinate to succinic acid was calculated when the operating parameters were optimized. Finally, the effect of impurities, such as corn steep oil, yeast extract, and dextrose on the electrodialysis efficiency was also studied.

• Structural Engineering and Mechanics
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• v.46 no.5
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• pp.735-753
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• 2013

The wind load is always the dominant load of cooling tower due to its large size, complex geometry and thin-wall structure. At present, when computing the wind-induced response of the large-scale cooling tower, the wind pressure distribution is obtained based on code regulations, wind tunnel test or computational fluid dynamic (CFD) analysis, and then is imposed on the tower structure. However, such method fails to consider the change of the wind load with the deformation of cooling tower, which may result in error of the wind load. In this paper, the analysis of the large cooling tower based on the iterative method for wind pressure is studied, in which the advantages of CFD and finite element method (FEM) are combined in order to improve the accuracy. The comparative study of the results obtained from the code regulations and iterative method is conducted. The results show that with the increase of the mean wind speed, the difference between the methods becomes bigger. On the other hand, based on the design of experiment (DOE), an approximate model is built for the optimal design of the large-scale cooling tower by a two-level optimization strategy, which makes use of code-based design method and the proposed iterative method. The results of the numerical example demonstrate the feasibility and efficiency of the proposed method.