VALUE OF INCREASING KERNEL UNIFORMITY

Kernel size uniformity is an important physical quality attribute in terms of processing efficiency, quality control, and milling yield. This study developed optimal grain sorting strategies for elevators to use to increase kernel size uniformity and determined the size of potential benefits from sorting. Cluster analysis and global optimization were used to sort grain loads to increase kernel size uniformity. Cluster analysis and global optimization increased the percent flour yield relative to no sorting by 0.13% and 0.32% respectively. Cluster analysis and global optimization increased the daily milling income relative to no sorting by 105 dollars (5%) and 266 dollars (13%) respectively.Crop Production/Industries,

Design sensitivity analysis and optimization of built-up structures

Developments during the course of the research in design sensitivity analysis and optimization of built-up structures, with both sizing and shape design variables, show clearly that a unified variational approach to design sensitivity analysis can yield derivatives of structural response with respect to design. Rigorous and practically computable results for structural components and built-up structures have been demonstrated and used to solve design optimization problems

Yield-driven power-delay-optimal CMOS full-adder design complying with automotive product specifications of PVT variations and NBTI degradations

We present the detailed results of the application of mathematical optimization algorithms to transistor sizing in a full-adder cell design, to obtain the maximum expected fabrication yield. The approach takes into account all the fabrication process parameter variations specified in an industrial PDK, in addition to operating condition range and NBTI aging. The final design solutions present transistor sizing, which depart from intuitive transistor sizing criteria and show dramatic yield improvements, which have been verified by Monte Carlo SPICE analysis

"Dynamic Optimality of Yield Curve Strategies"

This paper formulates and analyzes a dynamic optimization problem of bond portfolios within Markovian Heath-Jarrow-Morton term structure models. In particular, we investigate optimal yield curve strategies analytically and numerically, and provide theoretical justification for a typical strategy which is recommended in practice for an expected change in the shape of the yield curve. In the numerical analysis, we utilize a new technique based on the asymptotic expansion approach in order to increase efficiency in computation.

Analysis-of-marginal-Tail-Means (ATM): a robust method for discrete black-box optimization

We present a new method, called Analysis-of-marginal-Tail-Means (ATM), for effective robust optimization of discrete black-box problems. ATM has important applications to many real-world engineering problems (e.g., manufacturing optimization, product design, molecular engineering), where the objective to optimize is black-box and expensive, and the design space is inherently discrete. One weakness of existing methods is that they are not robust: these methods perform well under certain assumptions, but yield poor results when such assumptions (which are difficult to verify in black-box problems) are violated. ATM addresses this via the use of marginal tail means for optimization, which combines both rank-based and model-based methods. The trade-off between rank- and model-based optimization is tuned by first identifying important main effects and interactions, then finding a good compromise which best exploits additive structure. By adaptively tuning this trade-off from data, ATM provides improved robust optimization over existing methods, particularly in problems with (i) a large number of factors, (ii) unordered factors, or (iii) experimental noise. We demonstrate the effectiveness of ATM in simulations and in two real-world engineering problems: the first on robust parameter design of a circular piston, and the second on product family design of a thermistor network

A cell-based smoothed finite element method for kinematic limit analysis

This paper presents a new numerical procedure for kinematic limit analysis problems, which incorporates the cell-based smoothed finite element method with second-order cone programming. The application of a strain smoothing technique to the standard displacement finite element both rules out volumetric locking and also results in an efficient method that can provide accurate solutions with minimal computational effort. The non-smooth optimization problem is formulated as a problem of minimizing a sum of Euclidean norms, ensuring that the resulting optimization problem can be solved by an efficient second-order cone programming algorithm. Plane stress and plane strain problems governed by the von Mises criterion are considered, but extensions to problems with other yield criteria having a similar conic quadratic form or 3D problems can be envisaged

Optimization of broaching design

Broaching is one of the most recognized machining processes that can yield high productivity and high quality when applied properly. One big disadvantage of broaching is that all process parameters, except cutting speed, are built into the broaching tools. Therefore, it is not possible to modify the cutting conditions during the process once the tool is manufactured. Optimal design of broaching tools has a significant impact to increase the productivity and to obtain high quality products. In this paper, an optimization model for broaching design is presented. The model results in a non-linear non-convex optimization problem. Analysis of the model structure indicates that the model can be decomposed into smaller problems. The model is applied on a turbine disc broaching problem which is considered as one of the most complex broaching operations

Optimization of extraction conditions of antioxidant activity from zingiber zerumbet oleoresin

The health promoting capacity of natural antioxidant from phytochemicals has increase attention from researchers and public. However, processing is affecting the activity and the bioavailability of bioactive compounds. Therefore, the optimization of extraction condition of antioxidant activity from Zingiber zerumbet oleoresin was investigated. A Box-Behnken design technique was employed to study the effect of different range parameters of soxhlet extraction. Analysis of variance and response surface methodology were applied to identify the optimal processing parameter. Independent variables were extraction time (8, 10 and 12), type of solvent used (hexane, acetone, ethanol) and blanching treatment (steam treated, boil treated, untreated). The response and variables were fitted well to each other by multiple regressions. All the independent parameters affected oleoresin yield and antioxidant activity significantly. The optimal processing parameter that fulfilled the requirement for yield of oleoresin and antioxidant activity were found to be 12 h extraction time, ethanol as the solvent used and untreated sample. While, the optimal yield of oleoresin was 13.05% w/w and antioxidant activity was 16.01% w/w