• Journal of Power Electronics
• /
• 제19권5호
• /
• pp.1108-1121
• /
• 2019

The non-inverting buck-boost converter (NIBB) is a step-up and step-down DC-DC converter suitable for wide-input-voltage-range applications. However, when the input voltage is close to the output voltage, the NIBB needs to operate in the buck-boost mode, causing a significant efficiency reduction since all four switches operates in the PWM mode. Considering both the current stress limitation and the efficiency optimization, a novel design methodology for the optimal phase-shift modulation of a NIBB in the buck-boost mode is proposed in this paper. Since the four switches in the NIBB form two bridges, the shifted phase between the two bridges can serve as an extra degree of freedom for performance optimization. With general phase-shift modulation, the analytic current expressions for every duty ratio, shifted phase and input voltage are derived. Then with the two key factors in the NIBB, the converter efficiency and the switch current stress, taken into account, an objective function with constraints is derived. By optimizing the derived objective function over the full input voltage range, an offline design methodology for the optimal modulation scheme is proposed for efficiency optimization on the premise of current stress limitation. Finally, the designed optimal modulation scheme is implemented on a DSPs and the design methodology is verified with experimental results on a 300V-1.5kW NIBB prototype.

• 한국에너지공학회:학술대회논문집
• /
• 한국에너지공학회 1997년도 추계학술발표회 논문집
• /
• pp.17-23
• /
• 1997

A methodology for on-line data reconciliation and optimization has been proposed to minimize the energy cost of a utility system. As industrial data tend to be corrupted by noise or gross error, fast and robust data reconciliation technique is essential for the on-line optimization of utility system. Thus, we propose the hierarchical decomposition approach that can be applicable to on-line data reconciliation and optimization. As this approach divides whole system into several subsystems and removes the nonlinearity of constraint systematically, it handles complexity of system easily and shows good performance in accuracy and computation speed. Through case studies, we prove that this methodology is a good candidate for on-line data reconciliation and optimization.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2004년도 춘계학술대회논문집
• /
• pp.352-355
• /
• 2004

The objective of this work is to develop a new design method to find optimal coils, especially the optimal coil configuration of an optical pickup actuator. In designing actuator coils, the developed Lorenz force in the coils along the desired direction should be made as large as possible while forces and torques in other directions should be made as small as possible. The design methodology we are developing is a systematic approach that can generate optimal coil configurations for given permanent magnet configurations. To consider the best coil configuration among all feasible coil configurations, we formulate the design problem as a topology optimization of a coil. The present formulation for coil design is noble in the sense that the existing topology optimization is mainly concerned with the design of yokes and permanent magnets and that the optimization of actuator coils is so far limited within shape or size optimization. Though the present design methodology applies to any problem, the specific design example considered is the design of fine-pattern tracking and focusing coils.

• 품질경영학회지
• /
• 제46권1호
• /
• pp.39-74
• /
• 2018

Purpose: For more than 30 years, robust parameter design (RPD), which attempts to minimize the process bias (i.e., deviation between the mean and the target) and its variability simultaneously, has received consistent attention from researchers in academia and industry. Based on Taguchi's philosophy, a number of RPD methodologies have been developed to improve the quality of products and processes. The primary purpose of this paper is to review and discuss existing RPD methodologies in terms of the three sequential RPD procedures of experimental design, parameter estimation, and optimization. Methods: This literature study composes three review aspects including experimental design, estimation modeling, and optimization methods. Results: To analyze the benefits and weaknesses of conventional RPD methods and investigate the requirements of future research, we first analyze a variety of experimental formats associated with input control and noise factors, output responses and replication, and estimation approaches. Secondly, existing estimation methods are categorized according to their implementation of least-squares, maximum likelihood estimation, generalized linear models, Bayesian techniques, or the response surface methodology. Thirdly, optimization models for single and multiple responses problems are analyzed within their historical and functional framework. Conclusion: This study identifies the current RPD foundations and unresolved problems, including ample discussion of further directions of study.

• Journal of Dairy Science and Biotechnology
• /
• 제41권2호
• /
• pp.45-56
• /
• 2023

This review serves two purposes: first, to promote the use of improved optimization techniques in response surface methodology (RSM); and second, to enhance the optimum conditions for the fermentation of probiotics. According to research in dairy science, Lactiplantibacillus plantarum K79 is a candidate probiotic that has beneficial health effects, such as lowering blood pressure. The optimum conditions for L. plantarumK79 to produce peptides with angiotensin-converting enzyme (ACE) inhibitory activity were proposed, through modeling each of ACE inhibitory activity and pH as a function of the four factors that are skim milk concentration (%), incubation temperature (℃), incubation time (hours), and starter added amount (%). To estimate optimum conditions, the researchers employed a desirability-based multi-response optimization approach, utilizing third-order models with a nonsignificant lack of fit. The estimated optimum fermentation conditions for L. plantarum K79 were as follows: a skim milk concentration of 10.76%, an incubation temperature of 36.9℃, an incubation time of 23.76 hours, and a starter added amount of 0.098%. Under these conditions, the predicted ACE inhibitory activity was 91.047%, and the predicted pH was 4.6. These predicted values achieved the objectives of the multi-response optimization in this study.

• 한국CDE학회논문집
• /
• 제7권1호
• /
• pp.27-33
• /
• 2002

MDO(Multidisciplinary Design Optimization) methodology is a new technology to solve a complicate design problem with a large number of design variables and constraints. The design of a dental implant system is a typical complicate problem, and so it requires the MDO methodology. Actually, several analyses such as rigid body dynamic analysis and structural stress analysis etc. should be carried out in the MDO methodology application to the design of a dental implant system. In this paper, as a first step of MDO methodology application to the design of a dental implant system, the impact force which is applied on the tooth in masticating is calculated through the rigid body dynamic analysis of upper and lower jaw-bones. This analysis is done using ADAMS. The impact force calculated through the rigid body dynamic analysis can be used for the structural stress analysis of a dental implant system which is needed for the design of a dental implant system. In addition, the rigid body dynamic analysis results also show that the impact time decreases as the impact force increases, the largest impact force occurs on the front tooth, and the impact force is almost normal to the tooth surface with a slight tangential force.

• 동아시아식생활학회지
• /
• 제24권2호
• /
• pp.208-216
• /
• 2014

The purpose of this study was the optimization of mixing ratio of rice flour, potato starch and soybean flour baking domestic rice cookies with nuts. Response surface methodology, with a central composite design comprising 5 levels and 3 variables, was used to identify the optimal combination of rice flour ($X_1$), potato starch ($X_2$) and soybean flour ($X_3$). The physical properties of 16 samples were analyzed, including color L (p<0.001), color a, color b (p<0.05), spreadability (p<0.05) and hardness (p<0.05). In sensory evaluations, color (p<0.05), flavor, taste (p<0.05), crunch (p<0.05) and overall quality (p<0.05) were differed significantly among the samples. The optimal compositional ratios were 78.90 g rice flour, 18.96 g potato starch, and 15.90 g the soybean flour in 420 g total weight.

• 한국식생활문화학회지
• /
• 제26권6호
• /
• pp.717-726
• /
• 2011

Response surface methodology (RSM) was performed in order to determine the optimal mixing conditions of different amounts of egg and sugar for the preparation of soybean pudding. The experiments were designed according to a central composite design by designating whole egg and sugar content as independent variables. Meanwhile, sweetness, Commission Internationale de I'Eclairage (CIE) color parameters (L*, a* and b* values), hardness, cohesiveness, springiness, and gumminess were response variables. Overall optimization, conducted by overlaying the contour plots under investigation, was able to determine the optimal range of dependent variables within which the 14 responses were simultaneously optimized. The point chosen as a representative of this optimal region corresponded to 50.00 g of whole egg and 31.66 g of sugar. Under these conditions, the model predicted L* value=80.03, a* value=-5.44, b* value=27.86, sweetness=21.23 ($^{\circ}Brix$), hardness=$25.45{\times}10^5$ (dyne/$cm^2$), cohesiveness=67.90 (%), springiness=46.20 (%), and gumminess=12.71 (g).

• Journal of Microbiology and Biotechnology
• /
• 제20권4호
• /
• pp.835-843
• /
• 2010

The objectives of this study were to investigate the effect of fermentation medium on the hydroxyl radical scavenging activity of exopolysaccharides from Inonotus obliquus by response surface methodology (RSM). A two-level fractional factorial design was used to evaluate the effect of different components of the medium. Corn flour, peptone, and $KH_2PO_4$ were important factors significantly affecting hydroxyl radical scavenging activity. These selected variables were subsequently optimized using path of steepest ascent (descent), a central composite design, and response surface analysis. The optimal medium composition was (% w/v): corn flour 5.30, peptone 0.32, $KH_2PO_4$ 0.26, $MgSO_4$ 0.02, and $CaCl_2$ 0.01. Under the optimal condition, the hydroxyl radical scavenging rate (49.4%) was much higher than that using either basal fermentation medium (10.2%) and single variable optimization of fermentation medium (35.5%). The main monosaccharides components of the RSM optimized polysaccharides are rhamnose, arabinose, xylose, mannose, glucose, and galactose with molar proportion at 1.45%, 3.63%, 2.17%, 15.94%, 50.00%, and 26.81%.

• Food Quality and Culture
• /
• 제2권1호
• /
• pp.13-19
• /
• 2008

Recently, though mulberry's superiority as a functional food has been proven, its use as a food material is limited. Therefore, in this study, to develop jelly using mulberry that is compatible with Korean tastes as health functional food by grafting the method to manufacture jelly consumed as a dessert or a snack in the west, according to the central composite design, mulberry jelly was produced by varying the content of citric acid ($X_1$), sucrose ($X_2$), and gelatin ($X_3$) at 5 levels. And by applying the response surface methodology, rheology and sensory preference experiment results were analyzed, the optimization of mulberry jelly manufacturing condition was carried out, and studies on the analysis of composition were performed. As the sensory preference of mulberry jelly, except the flavor, the remaining hardness, elasticity, sweetness, color, and the overall quality were found to be significant. And similarly, it was found to be influenced greatly by gelatin content generally. Based on the overlapped part of categories, in the range of factors that satisfy all the sensory categories, the value located in the middle was calculated, the optimization point was obtained, and it was found to be 6.2 g citric acid, 141.0 g sugar, and 13.5 g gelatin.