Selection of an optimal set of cutting-tools for a general triangular pocket

The size(s) of the cutting-tool (end-mill) chosen for machining a given pocket has a significant impact on the machining time. However, the selection of cutting-tool sizes is typically based on human judgment and estimates, and is therefore prone to be conservative and non-optimal. The focus of this paper is on the development of a procedure for selection of an optimal set of cutting-tools for staircase milling of general triangular pockets with round corners, such that the machining time is minimized. We first derive analytical models for determining the time for machining the pocket using a given cutting-tool. Subsequently, we employ a dynamicprogramming based approach that utilizes these analytical models to determine the best set of cutting-tools, from the available inventory of cutting-tools, to machine the pocket. The proposed approach can be extended for optimal selection of cutting-tools for rough-machining of 3-D sculptured cavities.     

Selection of the best calibration sample subset for multivariate regression

This paper discusses a methodology for selecting the minimum number of calibration samples in principal component regression (PCR) analysis. The method uses only the instrumental responses of a large set of samples to select the optimal subset, which is then submitted to chemical analysis and calibration. The subset is selected to provide a low variance of the regression coefficients. The methodology has been applied to UV-visible spectroscopy data to determine Ca(2+) in water and near-IR spectroscopy data to determine moisture in corn. In both cases, the regression models developed with a reduced number of samples provided accurate results. As far as precision is concerned, a similar root-mean-squared error of cross-validation (RMSECV) is found when comparing the new methodology with the results of the regression models that use the complete set of calibration samples and PCR. The number of analyzed samples in the calibration set can be reduced by up to 50%, which represents a considerable reduction in costs.     

Selection of optimal filters for multispectral imaging

Preece and Claridge [IEEE Trans. Pattern Anal. Mach. Intell. 26, 913 (2004)] have proposed a technique for selecting filters for the maximally accurate recovery of object parameters such as chromophore concentrations from a multispectral image of an object. Their selection criteria are derived from an analysis of a model of light propagation in the object and take into account both errors in the modeling process and errors in the image acquisition process, as well as the inherent behavior and structure of the model. We investigate their method on simulated image data and show that filters selected according to their criteria are demonstrably superior to other choices.     

Selection of optimal process analyzers for plant-wide monitoring

In this paper, the effect of process analyzer selection and positioning on plant-wide process monitoring is investigated. A fundamental problem in process analytical chemistry is the incomparability of different instrument characteristics. A fast but imprecise instrument is incomparable to a slow but precise instrument. Theory is developed to overcome this problem by using an abstract definition of a process analyzer. This definition allows us to put all instrument characteristics for a particular monitoring task on an equal footing. This results in a measurability factor M that expresses monitoring performance of any process measurement by combining instrument characteristics such as precision, sampling rate, grab size, response correlation, and delay time. Both the choice of location and the performance characteristics of different process analyzers can be evaluated using the measurability factor. The unifying nature of the measurability factor allows for a rational decision between completely different process analyzers and locations (Smilde et al., in this issue). The theory is illustrated and validated with an experiment. A tubular reactor for free-radical bulk polymerization of styrene is monitored by in-line short-wave near-infrared spectroscopy at different positions. Alternatively, product samples are collected for at-line near-infrared analysis. Both analyzers measure styrene monomer concentration. The analysis results are used to predict conversion as well as number and weight average molecular mass of the polystyrene reactor product. The theoretical measurability factors for this case study correspond well with the experimental findings.     

Selection of optimal ratios for resistance measures comparison

Translated from Izmeritel'naya Tekhnika, No. 1, pp. 44–45, January, 1990.     

Setting optimal production lot sizes and planned lead times in a job shop

In this research, we model a job shop that produces a set of discrete parts in a make-to-stock setting. The intent of the research is to develop a planning model to determine the optimal tactical policies that minimise the relevant manufacturing costs subject to workload variability and capacity limits. We consider two tactical decisions, namely the production lot size for each part and the planned lead time for each work station. We model the relevant manufacturing costs, entailing production overtime costs and inventory-related costs, as functions of these tactical decisions. We formulate a non-linear optimisation model and implement it in the Excel spreadsheet. We test the model with actual factory data from our research sponsor. The results are consistent with our intuition and demonstrate the potential value from jointly optimising over these tactical policies.     

亚像素数字散斑相关测量中计算窗口的选择

提出了一种亚像素数字散斑相关测量计算窗口的选择方法.采用模拟散斑图像,利用亚像素数字散斑相关测量中的相关系数插值法、拟合法及梯度算法原理,研究了计算窗口大小对这三种计算方法的测量精度和计算效率的影响,得出了不同亚像素精度要求下,可选择的计算方法及其最佳计算窗口.研究结果表明,测量精度越高,所需的计算窗口越大,选择合适的计算窗口可以提高测量精度和效率.     

Selection of multiple optimal absorption transitions for nonuniform temperature sensing

A crucial aspect in the design of sensors based on absorption spectroscopy involves selecting the optimal transitions. Therefore, the goal of this paper is to develop a method of selecting multiple optimal transitions for the measurement of nonuniform temperature distributions based on absorption spectroscopy. Previously developed methods are largely restricted to the relatively simple case of selecting two transitions for uniform distributions. Our new method addresses the restrictions of previous methods and is applicable to more general cases. The method was validated using both numerical tests and experimental results and is expected to be useful in the design of sensors based on multispectral absorption spectroscopy.     

Properties of an optimal linearization transformation

In this article, we develop properties of a transformation that was introduced by the authors in an earlier paper. This transformation enabled us to construct iterates which give, to any desired level of detail, the asymptotic behaviour of solutions of a certain class of nonlinear vector differential equations which approach a sink as time tends to infinity. First, we present smoothness results. Second, we show that this transformation is the optimal linearization transformation and satisfies the Hartman–Grobman conjugacy condition. Finally, we amend the aforementioned iterates to yield iterates which not only approximate solutions but are flows and yield higher-order conjugacy conditions. Examples are provided.     

Determination of unit load sizes in an AGV-based material handling system for an FMS

Unit load size is a key factor in an automated guided vehicle based material handling system for a flexible manufacturing system. Highlighting this aspect and its importance at the design stage, this paper presents an integer programming formulation of the problem of finding the optimal unit load size. Using an existing analytical model to decide the number of AGVs required, an algorithm based on branching and implicit enumeration and a heuristic have been developed. Revised computations due to dynamic system conditions such as changes in part mix are also possible with the proposed algorithms. The methodologies have been demonstrated using numerical examples.     

Optimal selection of the local storage sizes of an assembly system

This paper describes the design of an assembly system consisting of a set of work stations and a set of quality control stations, linked by a set of transporter stations; given that the processing rates of all the work stations and the transporter stations, the defective fraction of the workpieces at each quality control station, and the expected throughput rate of the system are specified. The minimum required local storage sizes of the work stations and the transporter stations are obtained such that the probability of finding either a work station or a transporter station blocked is sufficiently close to zero.     

Generating a representative keyword subset pertaining to an academic conference series

Scientometrics - The breadth and velocity of innovation has resulted in explosion of research documents day by day. Academic conferences are being arranged worldwide, most of them in regular...     

The construction of an optimal weakly divergence-free macroelement

The divergence-free finite element method (DFFEM) is a method to find an approximate solution of the Navier-Stokes equations in a divergence-free space. That is, the continuity equation is satisfied a priori. DFFEM eliminates the pressure from the calculations and reduces significantly the dimension of the system to be solved at each time step. For the standard 8-node velocity and 4-node pressure DFFEM, an optimal basis for the weakly divergence-free subspace is constructed such that each basis function has non-zero support on at most nine contiguous elements. Given this basis, weakly divergence-free macroelements are constructed.     

Selection of optimal displacement step of a transducer in ultrasonic control of complexly structured articles

The selection of the optimal displacement step of a dual-element mosaic ultrasonic transducer as it scans the surface of a controlled article for the purpose of increasing the signal-to-structural noise ratio in the course of ultrasonic thickness testing of complexly structured articles is considered.     

Selection of the optimal distribution of heat-transfer agent flows in a ventilated cassette radioelectronic apparatus

An algorithm for determining the optical distribution of heat-transfer agent flows is proposed, and recommendations regarding the solution of the optimization problem are given.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 50, No. 2, pp. 249–255, February, 1986.     

Determination of an optimal common due date and optimal sequence in a single machine job shop

In this paper we consider an n jobs one machine sequencing problem in which all jobs have a common due date and a deviation in its completion time occurs when a job is completed before or after the common due date. The objective is to find an optimal value of this common due date and a corresponding optimal sequence such that the mean absolute deviation of the completion times of the jobs in the optimal sequence from the corresponding optimal common due date is at its global minimum. Starting with an arbitrary sequence we relate the problem to a generalized linear goal program from which some basic results are proved using elementary properties of linear equations and a linear goal programming problem. Using these results and the idea of sensitivity analysis in linear programming, an algorithm is developed that determines the optimal due date and the corresponding optimal sequence yielding the global minimum value of the mean absolute deviation of the completion times of the jobs in the optimal sequence from the corresponding optimal common due date. In the end a numerical example to explain the algorithm is provided.     

不可逆四热源吸收式制冷机炯经济优化性能

应用有限时间热力学理论，基于利润率为目标函数，对牛顿传热规律下四热源吸收式制冷机进行优化分析，导出制冷机的[火用]经济优化性能，揭示了其与生态学优化性能的内在联系。所得结论可为四热源制冷机的优化设计和最佳工况选择等提供些新理论依据。