• Journal of Korean Society for Quality Management
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• v.48 no.1
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• pp.51-68
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• 2020

Purpose: The primary objective of this research is to develop the optimal operating conditions as well as their associated design spaces for a Cryogenic Submerged Arc Welding(SAW) process by improving its quality and productivity simultaneously. Methods: In order to investigate functional relationships among quality characteristics and their associated control factors of an SAW process, a stepwise design of experiment(DoE) method is proposed in this paper. Based on the DoE results, not only a multi-dimensional design space but also a safe operating space and normal acceptable range(NAR) by integrating statistical confidence intervals were demonstrated. In addition, the optimal operating conditions within the proposed NAR can be obtained by a robust optimal design method. Results: This study provides a customized stepwise DoE method (i.e., a sequential set of DoE such as a factorial design and a central composite design) for Cryogenic SAW process and its statistical analysis results. DoE results can then provide both the main and interaction effects of input control factors and the functional relationships between the input factors and their associated output responses. Maximizing both the product quality with high impact strength and the productivity with minimum processing times simultaneously in a case study, we proposed a design space which can provide both acceptable productivity and quality levels and NARs of input control factors. In order to confirm the optimal factor settings and the proposed NARs, validation experiments were performed. Conclusion: This research may provide significant contributions and applications to many SAW problems by preparing a standardization of the functional relationship between the input factors and their associated output response. Moreover, the proposed design space based on DoE and NAR methods can simultaneously consider a number of quality characteristics including tradeoff between productivity and quality levels.

• Advances in nano research
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• v.14 no.2
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• pp.155-164
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• 2023

Grain size in sheet metals in one of the main parameters in determining formability. Grain size control in industry requires delicate process control and equipment. In the present study, effects of grain size on the formability of steel sheets is investigated. Experimental investigation of effect of grain size is a cumbersome method which due to existence of many other effective parameters are not conclusive in some cases. On the other hand, since the average grain size of a crystalline material is a statistical parameter, using traditional methods are not sufficient for find the optimum grain size to maximize formability. Therefore, design of experiment (DoE) and artificial intelligence (AI) methods are coupled together in this study to find the optimum conditions for formability in terms of grain size and to predict forming limits of sheet metals under bi-stretch loading conditions. In this regard, a set of experiment is conducted to provide initial data for training and testing DoE and AI. Afterwards, the using response surface method (RSM) optimum grain size is calculated. Moreover, trained neural network is used to predict formability in the calculated optimum condition and the results compared to the experimental results. The findings of the present study show that DoE and AI could be a great aid in the design, determination and prediction of optimum grain size for maximizing sheet formability.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.5
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• pp.16-25
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• 2009

Testing engine performance using an engine dynamometer requires high technical researchers and many facilities. Nowadays, different variables of CAE program are used for identifying the engine performance instead of engine dynamometer test. This is more convenience, as it does not necessitate an abundance of engine dynamometer experiments and, in addition, produces better results. However, CAE programs also contain various variables which can affect engine performance. Those are coupled with each other, thus making it difficult to determine the effectiveness of different variables on engines. DoE (Design of Experiments) methodology is an efficient way to verify the magnitude of effectiveness on engine performance as well as making responses to be optimized at once without trial & error. This study used data from WAVE simulations, which modeled the DOHC SI engine with in-line 4 cylinders at 1500, 3000 and 4500rpm. DoE methodology is designed properly to determine the effectiveness of five variables on power, BSFC, and volumetric efficiency, as well as to find the optimal response conditions at each rpm through a minimized number of experiments. After finishing DoE process, all the results are examined concerning the reliability of test through a verification experiment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.10
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• pp.798-805
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• 2018

This study introduces an adaptive design of experiment (DoE) approach for the hypersonic shock-tunnel testing. A series of experiments are conducted to model the pitch moment coefficient of a cone as the function of the angle of attack and the pitch rate. An algorithm to construct the trajectory of the test model from the images obtained by the high-speed camera is developed to effectively analyze multiple time series experimental data. An adaptive DoE procedure to determine the experimental point based on the analysis results of the past experiments using the algorithm is proposed.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.12
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• pp.1175-1184
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• 2020

This research examines the personal (i.e., Machiavellianism) and situational factors (i.e., tax climate) that are believed to be psychologically salient aspects in tax compliance. To the best of our knowledge, no research has been carried out to investigate the interaction effect of the two factors. This study uses a paper-and-pencil laboratory experiment 2x2 between-subject factorial design that involved 158 participants. The results indicate that a taxpayer who has a low Machiavellianism score or who is in a high synergistic tax climate reports a higher level of income. In the high synergistic tax climate, where tax norms apply, personal ethics do not play a significant role in tax compliance decisions. Where the synergistic relationship between taxpayer and authorities is low, personal ethics play an important role, i.e., low Machiavellians report a higher reported income than high Machiavellians do. This research contributes to the literature that deviates from the traditional model of tax compliance. Taxpayers are not always rational, but they might pay tax for reasons other than financial motives (Alm, 1991, 2018), that is, personal ethics in this study. This research implies the need for policymakers to consider other approaches rather than only relying on audits and fines.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.6
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• pp.216-225
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• 2023

This paper describes the finite element analysis and die design change of cold heading punching process to increase the cold forging tool life and reduce the tool wear and stress concentration. Through this study, the optimization of punch tool design has been studied by an analysis of tool stress and wear distribution to improve the tool life. Plastic deformation analysis was carried out in order to understand the cold heading process between tool and workpiece stress distribution. Cold heading punch die design was set up to each process with different four types analysis progressing, the cold heading punch dies shapes with combination of point angle and punch edge corner radius shapes of cold forging dies, punch die material properties and frictional coefficient. The design parameters of point angle and corner radius of punch die geometry, die material properties and frictional coefficient were selected to apply optimization with the DoE (design of experiment) and Taguchi method. DoE and Taguchi method was performed to optimize the cold heading punch die design parameters optimization for bolt head cold forging process, it was possible to expect an reduce the cold heading punch die wear to the 37 % compared with current using cold heading punch in the shop floor.

• Journal of Life Science
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• v.33 no.3
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• pp.268-276
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• 2023

This study was conducted to optimize the formulation conditions of the immediate-release layer of carvedilol in the development of a two-layer tablet formulation for carvedilol and ivabradine. Using a 2⁴+3 full-factorial design of experiments, excipients (microcrystalline cellulose, citric acid, and crospovidone) of the carvedilol immediate-release layer (wet granulation part) and process parameters for the tablet compression process (main compression) were optimized, and seven types of each dependent variable (assay, content uniformity, hardness, friability, disintegration, and dissolution [pH 1.2 and 6.8]) were evaluated using design expert software. The analysis of variance results confirmed that the main compression has a significant effect on hardness, friability, and disintegration time and that microcrystalline cellulose has a major effect on friability and dissolution. In addition, it was confirmed that citric acid has a significant effect on friability. Crospovidone affects friability and dissolution. According to the design space from the design of the experiment results, the optimized range is microcrystalline cellulose (~18.0-32.0 mg), citric acid (~0.5-12 mg), and main compression (~615-837 kgf). Consequently, this study confirmed the availability of manufacturing the carvedilol immediate-release layer in which all risk factors evaluated in the initial risk assessment are removed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.6
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• pp.251-261
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• 2022

This paper describes the finite element analysis and die design change of spring retainer forging process to reduce the cold forging load and plastic forming stress concentration. Plastic deformation analysis was carried out in order to understand the forming process of workpieces and elastic stress analysis of the die set was performed in order to get basic data for the die fatigue life estimation. Cold forging die design was set up to each process with different four types analysis progressing, the upper and lower dies shapes with combination of fillets and chamfers shapes of cold forging dies. This study suggested optimal cold forging die geometry to reduce cold forging load. The design parameters of fillets and chamfers are selected geometry were selected to apply optimization with the DoE (design of experiment) and Taguchi method. DoE and Taguchi method was performed to optimize the workpiece preform shape for spring retainer forging process, it was possible to expect an increase in cold forging die life due to the 20 percentage forging load reduction.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.2
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• pp.284-289
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• 2014

The experiment was conducted to evaluate the ingestive behavior of lambs confined in individual and group stalls. We used thirty-four lambs in their growing phase, aged an average of three months, with mean initial live weight of $17.8{\pm}5.2$ kg. They were allotted in a completely randomized design with 24 animals kept in individual stalls and 10 animals confined as a group. The experiment lasted for a total of 74 days, and the first 14 days were dedicated to the animals' adaption to the management, facilities and diets. The data collection period lasted 60 days, divided into three 20-d periods for the behavior evaluation. The animals were subjected to five days of visual observation during the experiment period, by the quantification of 24 h a day, with evaluations on the 15th day of each period and an interim evaluation consisting of two consecutive days on the 30th and 31st day of the experiment. The animals confined as a group consumed less (p<0.05) fiber. However, the animals confined individually spent less (p<0.05) time on feeding, rumination and chewing activities and longer in idleness. Therefore, the lower capacity of lambs confined in groups to select their food negatively affects their feeding behavior.

• Analytical Science and Technology
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• v.33 no.6
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• pp.252-261
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• 2020

Currently, the potentiometric titration and the high pressure liquid chromatography (HPLC) method were utilized in Korean Pharmacopoeia XII (KP XII) as well as other pharmacopoeias (USP, EP, BP) for determination of loperamide hydrochloride in raw materials and capsules, respectively. The research objective is to overcome the remaining drawbacks from current methods such as solubility of mobile phase (KP XII), less scientific approach (USP 43) or using paired-ion chromatography reagent which shows some limitations (BP2017 and other formulation monographs). The proposed method was optimized by Design of Experiment (DoE) tool to obtain the satisfied method for determination of loperamide hydrochloride. The optimal condition was performed on the common C18 column (150 mm × 4.6 mm; 5 ㎛) using isocratic elution with the mobile phase containing 40 mM of potassium phosphate monobasic (pH 3.0) and acetonitrile (56:44), at a flow rate of 0.7 mL/min. The optimized method was validated and met the requirements of the International Conference on Harmonization. The developed method was applied to determine loperamide hydrochloride in capsules and can be used to update the current monograph in KP XII.