Search

Computer experiments are constructed to simulate the behavior of complex physical systems. Uniform designs have good performance in computer experiments from several aspects. In practical use, the experimenter needs to choose a small size uniform design at the beginning of an experiment due to a limit of time, budget, resources, and so on, and later conduct a follow up experiment to obtain precious information about the system, that is, a sequential experiment. The Lee distance has been widely used in coding theory and its corresponding discrepancy is an important measure for constructing uniform designs. This paper proves that all the follow up designs of a uniform design are uniform and at least two of them can be used as optimal follow up experimental designs. Thus, it is not necessary that the union of any two uniform designs yields a uniform sequential design. Therefore, this article presents a theoretical justification for choosing the best follow up design of a uniform design to construct a uniform sequential design that involves a mixture of ω ≥ 1 factors with βk ≥ 2, 1 ≤ k ≤ ω levels. For illustration of the usage of the proposed results, a closer look is given at using these results for the most extensively used six particular cases, three symmetric and three asymmetric designs, which are often met in practice. [ABSTRACT FROM AUTHOR]

A hybrid method is proposed for optimizing rigid tapping parameters and reducing synchronization errors in Computer Numerical Control (CNC) machines. The proposed method integrates uniform design (UD), regression analysis, Taguchi method, and fractional-order particle swarm optimizer (FPSO) to optimize rigid tapping parameters. Rigid tapping parameters were laid out in a 28-level uniform layout for the experiments in this study. Since the UD method provided a layout with uniform dispersion in the experimental space, the UD method’s uniform layout provided iconic experimental points. Next, the 28-level uniform layout results and regression analysis results were used to obtain significant parameters and a regression function. To obtain the parameter values from the regression function, FPSO was selected because its diversity and algorithmic effectiveness are enhanced compared with PSO. The experimental results indicated that the proposed method could obtain suitable parameter values. The best parameter combination in FPSO yielded the best results in comparisons of the non-systematic method. Next, the best parameter combination was used to optimize actual CNC machining tools during the factory commissioning process. From the commissioning process perspective, the proposed method rapidly and accurately minimizes synchronization error from 23 pulses to 18 pulses and processing time from 20.8 s to 20 s. In conclusion, the proposed method reduced the time needed to tune factory parameters for CNC machining tools and increased machining precision and decreased synchronization errors.

The paper introduces a practical method for the construction of large-scale point sets for analysis of computer models. The constructed experimental design is useful for (probabilistic) integration, construction of approximation or a screening. The essence of the presented approach is the stratification of the design domain into an orthogonal grid of substrata and a subsequent tiling with tiles of points. If optimized, such tiles experience a major reduction of the number of degrees of freedom in the optimization process. That way, optimal or near-optimal point patterns can be feasibly identified and are further utilized for construction of larger point sets, thanks to the idea of self-similarity and structured space stratification The space-filling properties of the resulting point sets may be further enhanced by various "scrambling" strategies, which may remove the undesired sample collapsibility achieved via regular tiling. The performance of the constructed point sets is compared to Quasi Monte Carlo (QMC), Randomized Quasi Monte Carlo (RQMC) sequences, which are still today considered by engineers and even scientists as choices for variance reduction of numerical integration Further, the mentioned sampling strategies are compared in the terms of robustness when integrating a multivariate function with a localized feature. It is concluded that the proposed sampling approach reaches a superior performance in numerical integration and identification of function extremes as compared to sampling methods used by practicing researchers and engineers. Additionally, the reader is supplied with the open-access, ready-to-use implementation of the presented algorithm named SampleTiler. • Construction of large-scale point samples by balancing the bias–variance tradeoff. • Stratification of the design domain and subsequent tiling with tiles of points. • Construction of large optimized experimental designs due to self-similarity. • Superior performance of samples as compared to commonly used methods. • Open-access Python code provided on a GitHub repository. [ABSTRACT FROM AUTHOR]

This paper aims to minimize the tracking error of a laser auto-focus system that in developing treatment, due to uncertainty setting and modeling of its control system. The error is derived from the imperfect response to the standardized object reference. Optimizing procedure is obtained via multi-variable parameters by using a UniNeuro-hybrid uniform design genetic algorithm (HUDGA). In general, the parameter setting of a servo-controller is determined by some complex analysis or the trial-and-error of an expert person; when the controlled model is distinctly undefined, the process requires considerable time. The UniNeuro-HUDGA requires only 40 experiments to be conducted in the uniform design (UD) of building the metamodel via a neural network (UniNeuro), which is used as the fitness function in the optimization procedure by combining a genetic algorithm with UD. UD is then embedded in the HUDGA for initializing and enriching the solution set, whereas chromosomes used in crossover and mutations generated by UD chromosomes are individually conveyed using a selection procedure combined with the Euclidean distance; then, the optimized setting has investigated by the equipment. This paper concludes that the proposed algorithm optimizes the adjustable parameters of a servo-controller and outperforms the trial-and-error of an expert person.

Modified Bubble Column Extraction with Ultrasonic Bath (BCE-UB) method was used to extract atropine from the stem and leaves of Atropa belladonna. Optimum condition were obtained with Kamada solvent which was chloroform-methanol-ammonia 15:15:1(v/v/v) as extraction solvent, the particle size of less than 350 µm, an extraction time of 23.95 min, a liquor to material ratio of 15.08 mL/g and an air flow of 6.31 mL/min.g. In this state, percent of extracted atropine was calculated which was equal to 6.81%. Percent of extracted atropine was 6.31% that showed a little difference compared to the predicted value. In order to study the effect of bubbles on the extraction rate, the same extraction with the previous method was performed in a stirred tank. Percent of atropine was 5.59%.

The modal analysis of steering system was made because of the excessive vibration of a certain forklift truck when the engine at medium and low speed conditions at first in this paper. The vibration optimum design was put forward to reduce the vibration of steering wheel by the method of Uniform Design. the test results show that the stiffness of improved steering system is increased and the vibration is decreased obviously on the basis of the invariability of costs,especially when the engine at low speed,the acceleration of vibration on direction x,y,z are reduced 83. 8%,90. 3%,83. 7% respectively. The optimum method provides references for the optimum design of body and frame type structures.

This study presents an optimization procedure for the design of a one-piece zirconia ceramic dental implant that uses finite element simulation with dynamic loads and experimental validation using a fatigue test. The key dimensions of the implant's shape are the factors for the simulation. Their effect on micromotion is determined using a uniform design of experiment. The Kriging interpolation method and a genetic algorithm (KIGA) are used to optimize the geometric features, in order produce an optimized one-piece dental implant model. The model is fabricated using a three-dimensional slurry printer. The lifetime of the zirconia implant is evaluated using a fatigue test. The numerical result for the objective function shows that the micromotion for the optimized dental implant is 27.58 μm, which is less than the value of 72.62 μm for the original numerical prediction. The safety factor also increases to 1.54 from 1.16. This demonstrates that the optimized dental implant is better than the original design because the degree of micromotion is much lower than the stability threshold. The fatigue test also shows that the safety factor increases to 1.54. Therefore, the proposed procedure produces a dental implant with an optimized shape. [ABSTRACT FROM AUTHOR]

Computer experiments have become ubiquitous across the engineering, physical and chemical sciences. Computer experiments are constructed to emulate the behavior of a physical system. Assume that we perform an experiment using a two-level uniform design. If, after obtaining data, we decide additional runs of the computer simulator are needed, how to add more runs after collecting our data? How to design the experiment to efficiently extract useful information from it? In this paper, we try to answer these questions by providing a new approach for constructing efficient uniform designs by adding new runs to an existing uniform design. The optimization criteria are the uniformity criteria measured by Lee, symmetric, wrap-around, centered and mixture discrepancy and the orthogonality criteria measured by the B-criterion and the O-criterion. We investigate the relationship between orthogonality and uniformity criteria in view of analytical expressions and lower bounds. [ABSTRACT FROM AUTHOR]

Abstract Doubling and level permutation of factors are widely used in the construction of uniform designs and minimum aberration designs. Based on the viewpoint that double design is the orthogonal combination of all possible level permutations of its initial two-level design, a method of tripling for three-level design, which triples both the run size and number of factors of initial design, is proposed by orthogonally combining all possible level permutations of its initial design in this paper. The wrap-around L 2 -discrepancy of triple design is expressed by the wordlength pattern of its initial design, and a tight lower bound of the wrap-around L 2 -discrepancy of triple design is obtained. An efficient method for constructing uniform minimum aberration designs is proposed based on the projection of triple design. These constructed designs have better properties, such as minimum aberration and lower discrepancy, than existing uniform designs, and are recommended for use in practice. Highlights • A new concept named as triple design is proposed for fractional factorial design. • The WD of triple design is expressed by the wordlength pattern of its initial design. • A tight lower bound of the wrap-around L2-discrepancy of triple design is obtained. • Triple design has better properties, such as minimum aberration, lower discrepancy. [ABSTRACT FROM AUTHOR]

In order to obtain a more accurate interval of an accident reconstruction result, two modified experiment design methods were proposed. The first is based on the orthogonal design (OD) and it is named as the orthogonal-based design (OBD), while the other is based on the uniform design (UD) and it is named as the multi-response surface-uniform design (MUD). Furthermore, some conclusions are given according to seven numerical cases: results obtained from the Latin hypercube sampling design (LHS) are the worst, while those obtained from the UD are the last but one, and all are worse than the results obtained from the OBD and the MUD. Furthermore, some conclusions about the number of simulation runs of each design of experiment (DOE) can be given: if the second order response surface model is selected, the number of simulation runs of the LHS is the same as the UD, and all are lesser than the number of simulation runs of the OBD and the MUD in most cases. As for the OBD and the MUD, the number of simulation runs of the OBD is lesser than the number of simulation runs of the MUD, but the MUD can be applied more widely than the OBD. Finally, a true vehicle-pedestrian accident case is given, Pc-Crash was used to reconstruct the accident based on all traces provided by the police, and the interval of the impact velocity of the vehicle was calculated using the OBD, results showed that the research is meaningful in practice. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In response to the declining availability of natural resources to use as raw and construction materials, the use of waste materials partial or complete alternative of natural resources for the preparation of lightweight aggregate (LWA) has been a hot topic of research. This study investigated the possibility of using the municipal solid waste incineration (MSWI) fly ash, electrolytic manganese residues (EMR) and Coal fly ash as materials to prepare LWA by a high temperature sintering process. The uniform design (UD) method was employed to design the experiments of LWA, and a quadratic regression method was used to establish regression model for studying the mixture ratio of raw materials and the properties of LWA. The results indicated that the data were well fitted by the regressed second-order polynomial models, the interaction between the raw materials was investigated. Optimum the mixture ratio of raw materials to meet three response were obtained and verified, EMR was 49.19%, MSWI fly ash was 12.91% and Coal fly ash was 37.90%. The pellets were prepared according to this optimal recipe and calcined at 1140 °C for 13 min to meet light - aggregate of GB/T 17431.2 - 2010 standard. The heavy metal extraction values of LWA were all much lower than the standard described in "Identification standard of hazardous waste-identification of leaching toxicity (GB 5085.3 - 2007)" and the "landfill standard (GB 16889 - 2008)" achieving the dual purpose of detoxification and utilization of MSWI fly ash and EMR. [ABSTRACT FROM AUTHOR]

Aiming at the problem of pressure uniformity optimization of hydrodynamic pressure suspension polishing flow field, the influence of process parameters on the dynamic pressure in processing area was studied. Computational fluid dynamics (CFD) and uniform design method were used to solve the pressure mean and pressure standard deviation of the processing area under different process parameters. The mathematical model of the fitting of process parameters and pressure mean or pressure standard deviation were established by multiple nonlinear regression method, the process parameters were optimized by genetic algorithm and through numerical model. The pressure distribution and processing effect before and after optimization were compared. The results indicate that there is a nonlinear regression relationship between the selected process parameters, the pressure mean and pressure standard deviation. The optimal process parameters are h = 285 μm, ω = 1 300 r/min, and φ = 0. 12. Under this parameter, the flow field pressure in the workpiece area is the largest and the pressure standard difference is the least, which helps to remove the material quickly and evenly. [ABSTRACT FROM AUTHOR]

To optimize the culture medium for adventitious root (AR) culture of Echinacea pallida, the nitrogen, phosphorus, and sucrose with their different concentrations were combined by using the uniform design method in AR suspension culture. The maximum AR dry weight (5.2 g L−1), phenolic (57.3 mg g−1), and flavonoid (40.8 mg g−1) contents were determined when AR culture medium of the three-quarter strength Murashige and Skoog medium contained 45 mM nitrogen and 1.56 mM phosphorus and was supplemented with 50 g L−1 sucrose and 1 mg L−1 indole-3-butyric acid. Productivities of phenolics and flavonoids of ARs reached 297.9 and 211.9 mg L−1, respectively. The optimized culture medium was used in the AR bioreactor culture. The kinetic study was conducted to select a suitable culture period. When ARs were cultured in a 5-L air-lift bioreactor for 30 days, the accumulation of AR biomass (76.1 g L−1 fresh weight and 7.5 g L−1 dry weight) and bioactive compounds (53.5 mg g−1 phenolics and 37.6 mg g−1 flavonoids) reached the maximum values, and the productivities of phenolics and flavonoids were 398.7 and 280.4 mg L−1, respectively. The bioreactor-cultured AR extracts at 0.8-1.4 mg L−1 inhibited tyrosinase activity, revealing that E. pallida ARs can potentially block melanin formation. Thus, E. pallida ARs has a feasible alternative plant material to be used in the industrial production of whitening cosmetic products. [ABSTRACT FROM AUTHOR]

A method based on uniform experimental design and the backpropagation (BP) neural network to analyze the sensitivity of measurement errors in the binocular vision system is proposed. Six main error factors that affect the measurement accuracy of the system are summarized according to the binocular vision principle. The measurement experiment was carried out based on uniform design. The mapping relationship between the total measurement error and each error factor was established by BP neural network. Then the sensitivity coefficient of each error factor can be calculated by this mapping. These sensitivity coefficients provide a measure of the degree of influence each factor had on the total measurement error. The results show that the sensitivity coefficients of lens distortion and the image noise are 0.287 and 0.243, respectively, which are significantly higher than the other error factors. This means that these two error factors need to be emphatically suppressed during the measurement process. [ABSTRACT FROM AUTHOR]

The purpose was to clarify the relationship between the main process parameters of micro-plasma cladding and the comprehensive quality (geometry, microstructure and wear rate of cladding track). Self-fluxing ferrous alloy powders were fabricated on Q235 substrate. Based on the uniform design, the distribution of the experimental samples was designed reasonably in the sample space, which greatly improved efficiency and reduced costs. After a series of microstructural characterization, there was no difference in the phase composition of all samples, but the average grain size had a significant difference, which resulted in the change of wear rate. And the relationship among micro-hardness, average grain size and wear rate of the track had also been investigated. Subsequently, an optimization model was established and the optimal process parameters were obtained with excellent wear rate under the geometric constraints. The correctness of optimization model was verified by experiments. [ABSTRACT FROM AUTHOR]

The objectives of this research were to reveal how main working parameters of ultrasonic atomizers would influence key properties of the atomized nutrient solution in an aeroponics system. The Yamazaki tomato nutrient solution was selected as a nutrient example. Uniform design (UD) method U12 (12²×13) was adopted to arrange the test. In this test, spraying time and interval time were taken as quantitative factors with 12 levels (10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, and 120 min, respectively), and ultrasonic atomizer frequency was taken as qualitative factor with 3 conditions (28 kHz, 107 kHz, 1.7 MHz). Based on test data, two regression formulations used to predict the values of ΔEC, and ΔpH of atomized Yamazaki tomato nutrient solution was established and inspected. The spraying interval time of ultrasonic atomizers had no significant effect on EC and pH of the atomized Yamazaki tomato nutrient solution; the ultrasonic atomizer frequency was more effective than spraying time on the values of EC and pH; the values of EC and pH became maximum at (f3, T1) = (1.7 MHz, 120 min) and minimum at (f1, T1) = (28 kHz, 10 min). It was concluded that the effect of high-frequency (1.7 MHz) ultrasonic atomizer on EC and pH of the Yamazaki tomato nutrient solution was beyond the standard value for tomato growth. Therefore, the high-frequency (1.7 MHz) ultrasonic atomizer is not suitable for aeroponics cultivation when using the Yamazaki tomato nutrient solution as aeroponics nutrient solution. [ABSTRACT FROM AUTHOR]

The aim of the current study was to reduce the fat content of salad dressings using microparticulated egg white proteins (MEWP) as fat mimetic. In this regard, the effects of heating and shearing conditions on textural properties, rheological properties, and color parameters of MEWP were investigated. Statistical analysis with uniform design methodology showed that there was a significant correlation between investigated responses and process variables (P ≤ 0.05) except for rotational speed. Based on the optimal conditions (13 min for heat time, 3.6 for solution pH value, 90g/L for protein addition amount, 60 s for shear time, lOOOOr/min for rotational speed) produced by the optimization of process conditions, the textural and sensory properties, rheological properties, and color of MEWP were comparable to the commercial salad dressing (CSD). The results indicated that MEWP can be used as fat mimetic for the production of low-fat salad dressings. [ABSTRACT FROM AUTHOR]

Summary: The settlement is regarded as an important index in underground engineering. When tunneling under across the operational subway tunnel, settlement of the operational tunnel should be monitored. To control the tunneling‐induced movement of the operational subway tunnel, the operation parameters of mechanized‐tunneling, namely, face and grout pressures, should be kept in a specific range. A hybrid approach is proposed utilizing uniform design method, and radial basis function neural network to develop the relation of settlement and related influential factors. Such connection is used as a tuning module for tunneling boring machine (TBM). Furthermore, implementing total station robot and soft computing method of support vector machine (SVM), a forecast model for settlement of the rail is established. The prediction tool SVM is improved by using the particle swarm optimization. Parameters c and g from the SVM and γ in the kernel function of the SVM are optimized using the particle swarm optimization. An illustrative case in Changsha Metro Line 3 constructing under the Metro Line 1 tunnel validates the prediction model. The feasibility of the metamodel is demonstrated by means of the example. [ABSTRACT FROM AUTHOR]

In this paper, an interval type-2 neuro-fuzzy system with uniform design-based rule generation approach is proposed, and Begian-Melek-Mendel method is used for defuzzification. To the consequent learning, two least squares methods are involved in the consequent design for the interval type-2 neuro-fuzzy system, one is the recursive singular value decomposition, and the other is the weighted least squares estimator. Besides the interval type-2 neuro-fuzzy system modelling, another aim of this paper is to verify the interval type-2 neuro-fuzzy systems’ performance from the point of view of statistics, not just the average prediction accuracy or the best results from hundreds of iteration. With this in mind, a distribution-free least squares estimation method is used to assess the interval type-2 neuro-fuzzy system’s modelling capability. [ABSTRACT FROM AUTHOR]

As one of the important renewable energy, hydropower is experiencing a booming development period throughout the world in recent years. By the end of 2016, hydropower has occupied 20.1% installed capacity and 19.5% generation in China. Thus, it is of great importance to develop some effective methods to guarantee the overall generation benefit of hydropower system. As a famous optimization tool to solve this problem, the progressive optimality algorithm cannot effectively handle with large-scale hydropower system because its computational burden grows exponentially with the increasing number of hydroplants. Thus, in order to effectively alleviate the dimensionality problem, a novel method called uniform progressive optimality algorithm is introduced here. In the presented method, the complex multistage problem is firstly divided into several two-stage optimization subproblems, and then the uniform design is adopted to sample a small subset from all the possible state vectors at each subproblem, while the successive approximation strategy is adopted to gradually improve the quality of solution. The results from a real-world hydropower system of China indicate that compared with progressive optimality algorithm, the proposed method has superior performance in execution efficiency and convergence speed, which is an effective alternative method for the complex hydropower system operation problem. [ABSTRACT FROM AUTHOR]

In many industrial trials, the second-order models may not be enough to fit the non linearity of the underlying model, and the third-order models may be considered. In this article, the orthogonal-array composite design (OACD), combined with two-level OA and four-level OA and denoted by OACD4, is proposed to estimate the second-order and third-order models. It is shown that OACD4 has good properties and has higher efficiency than other types of designs for the third-order models, and OACD4 can perform multiple analysis for cross-validation. The usefulness of OACD4 is also shown by a case study for polymer synthesis experiment. [ABSTRACT FROM AUTHOR]

A low treatment capacity and unstable operation are the main drawbacks of the anaerobic digestion of food wastes. The present work improved the efficiency and stabilization of the anaerobic digestion of food wastes using digesters with a polyamide stirring rake (DPSR) and compared it to a traditional digester with a stainless-steel stirring rake (DSSSR). The DPSR had a higher reliability and produced 3.97 times the methane yield of DSSSR in batch experiments at high loading rates (105 VS/L). Uniform design experiments were applied to investigate the relationship between methane yield and the stirring factors of the DPSR. A regression analysis of the uniform design indicated that stirring factors synergistically affect methane yield. The experiment verifying the optimal conditions showed that in the DPSR with 82 r/min stirring intensity and 10 min/d stirring time, the first 20 days of methane yield (392.1 mL/g VS) achieved to 85.26% of the theoretically derived methane yield. In brief, in the anaerobic digestion of food wastes for high methane production and stable operation, the DPSR was more beneficial for the anaerobic digestion of food wastes than the DSSSR. [ABSTRACT FROM AUTHOR]

The heat transfer and pressure drop under oscillatory condition in helical rectangular channel heat exchangers are numerically investigated by using uniform design method. The correlations of three models with different ratios of height to width are obtained. The results show that the channel with the largest ratio of length to width has a larger heat transfer rate and a lower friction factor. Then, the field synergy principle is used to analyze heat transfer enhancement of helical rectangular channel heat exchanger. Besides, the Performance Evaluation Criteria (PEC) method has been used to compare the thermal-hydraulic performances of helical rectangular channel heat exchanger with helically coiled tube heat exchanger. The results show that the helical rectangular channel heat exchanger has a better performance operating at high frequency and high velocity. So it is more suitable for the Stirling type machines. Finally, a helical rectangular channel heat exchanger was experimentally used in our thermal-compressor system to verify the present numerical result. [ABSTRACT FROM AUTHOR]

In real-life projects, in order to obtain precious information about the process, we often partition the experiment into two stages with equal size. The main purpose of this article is to study how to choose the first stage experimental designs (FSED) and the second stage experimental designs (SSED) to construct uniform or at least good approximation to uniform (GATU) two-stage experimental designs (TSED) that involve a mixture of ω1≥1 factors with μ1≥2 levels and ω2≥1 factors with μ2≥2 levels whether regular or nonregular. Through theoretical justification, this paper proves that the SSED is uniform (GATU) if and only if the FSED is uniform (GATU), the TSED is uniform (GATU) if and only if its corresponding complementary TSED is uniform (GATU), and the TSED is uniform or at least GATU if and only if the FSED is uniform. [ABSTRACT FROM AUTHOR]

The research of developing efficient methodologies for constructing optimal experimental designs has been very active in the last decade. Uniform design is one of the most popular approaches, carried out by filling up experimental points in a determinately uniform fashion. Applications of coding theory in experimental design are interesting and promising. Quaternary codes and their binary Gray map images attracted much attention from those researching design of experiments in recent years. The present paper aims at exploring new results for constructing uniform designs based on quaternary codes and their binary Gray map images. This paper studies the optimality of quaternary designs and their two and three binary Gray map image designs in terms of the uniformity criteria measured by: the Lee, wrap-around, symmetric, centered and mixture discrepancies. Strong relationships between quaternary designs and their two and three binary Gray map image designs are obtained, which can be used for efficiently constructing two-level designs from four-level designs and vice versa. The significance of this work is evaluated by comparing our results to the existing literature. [ABSTRACT FROM AUTHOR]