Minimizing earliness–tardiness on a single burn-in oven with a common due date and maximum allowable tardiness constraint

This paper considers a scheduling problem for a single burn-in oven in the semiconductor manufacturing industry where the oven is a batch processing machine with restricted capacity. The batch processing time is set by the longest processing time among those of all the jobs contained in the batch. All jobs are assumed to have the same due date. The objective is to minimize the sum of the absolute deviations of completion times from the due date (earliness–tardiness) of all jobs under the constraint that the maximum tardiness should be less than or equal to the maximum allowable time value. We suggest several two-phase heuristic algorithms for this problem. In the first phase, some heuristic algorithms are developed without maximum allowable tardiness constraint. If the schedule from the first phase violates the maximum tardiness constraint, then the schedule is changed to satisfy maximum allowable tardiness constraint in the second phase. The suggested heuristics are based on genetic algorithms and dominance properties of optimal schedules. We present the results of computational experiments that clearly show the solution quality obtained by the suggested heuristics.     

Sequencing and batching procedures for minimizing earliness and tardiness penalty of order retrievals

External involvement in new product development (NPD) has received increasing attention from both academicians and practitioners in recent years. While external involvement has been studied extensively, the academic understanding on how external involvement influences firm performance and the role of time-to-market of new products is still very limited. Drawing on the literature on innovation search and knowledge-based view, we develop a conceptual framework in which external involvement is linked to time-to-market of new products and firm performance. We tested this model using data collected from 176 manufacturing companies in China. The results indicate that both customer and supplier involvement can contribute to the reduction of time-to-market of new products. We also show that time-to-market of new products completely mediates the relationships between two types of external involvement and two dimensions of firm performance. These findings have important implications for research and practice in both the external involvement and the NPD areas.     

Minimising earliness and tardiness penalties in single machine scheduling against common due date using imperialist competitive algorithm

In this paper a novel evolutionary-based approach is utilised for efficiently solving the NP-hard problem of scheduling numerous common-due-date jobs on a single machine. Minimising the sum of earliness and tardiness penalties for all jobs is considered as the target function. The performance of the proposed approach is examined through a computational comparative study with 280 benchmark problems with up to 1000 jobs where the numerical results indicate that it can produce ‘better’ solutions in less computational time when compared to benchmark results and the methods available in the literature, namely genetic algorithm (GA), Tabu search (TS) and differential evolution (DE).     

Parallel machine scheduling about an unrestricted due date and additional resource constraints

This research considers the problem of schedulingjobs on parallel machines with an unrestricted due date and additional resources. The objective is to minimize the total absolute deviation of job completion times about the common due date. This problem is motivated by restrictions that occur in the handling and processing of jobs in certain phases of semiconductor manufacturing and other production systems. It is shown that the problem is polynomial when there exists one single type of additional resource and the resource requirements per job are zero or one.     

Hydraulic drag due to division of a stream of fluid into two parallel channels with an arbitrary ratio of flow rates

An expression is derived for the hydraulic drag and results of calculations are compared with experimental data.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 41, No. 5, pp. 842–847, November, 1981.     

Computing electromagnetic field distribution due to an arbitrary shape exciter near multilayer slab conductors

We present a semianalytical method for calculating the electromagnetic field distribution in a multilayer slab conductor. This is a very advanced and comprehensive method because there is no limitation for the shape of the exciter and the number of layers (i.e., an exciter of any arbitrary shape and at any distance near the surface of a multilayer conductor with a large number of layers can be modeled). We solve the Helmholtz equation in three dimensions by separation of variables. We develop a two-dimensional fast Fourier transform (FFT) integral model and use exponential functions in the third dimension. We solve this integral model analytically and numerically by using the custom matrix form AX = B and a system of algebraic equations, respectively. To verify this method, we solve a simple example problem both by the new method and a finite-element method (FEM) program. The results are in good agreement with each other.     

Σ-separability of the far-field beam-pattern due to an arbitrary excitation-function over an elliptical-rim aperture

This study is the first in the phase-mode analysis literature to analytically characterise the far-field azimuth-elevation (?-?) beam-pattern due to any arbitrary excitation-function on an elliptical-rim aperture. The key findings include: such an arbitrary excitation-function's far-field beam-pattern is not always (?-?) separable. Nonetheless, this beam-pattern is ?-separable in the sense that it is a sum of (?-?) separable terms. Moreover, this sum may be approximated (with arbitrarily small truncation-error) as a finite-term summation. A ceiling of this truncation-error is derived.     

Transient thermal stresses in a transversely isotropic finite circular cylinder due to an arbitrary internal heat-generation

The transient thermal stresses in a transversely isotropic, finite, solid, circular cylinder resulting from a unsteady-state, axisymmetrical temperature field are examined. A general method of solution based upon a set of stress functions is presented for the case of an arbitrary internal heat-generation. The temperature field is exactly determined by combined use of finite Fourier-cosine and finite Hankel transforms. Numerical calculations are carried out for various cases of the thermal and elastic anisotropies of the materials.     

Single-machine common/slack due window assignment problems with linear decreasing processing times

This paper studies linear non-increasing processing times and the common/slack due window assignment problems on a single machine, where the actual processing time of a job is a linear non-increasing function of its starting time. The aim is to minimize the sum of the earliness cost, tardiness cost, due window location and due window size. Some optimality results are discussed for the common/slack due window assignment problems and two O(n log n) time algorithms are presented to solve the two problems. Finally, two examples are provided to illustrate the correctness of the corresponding algorithms.     

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.     

Active vibration control of an arbitrary thick smart cylindrical panel with optimally placed piezoelectric sensor/actuator pairs

Active vibration suppression of a simply supported, arbitrarily thick, transversely isotropic circular cylindrical host panel, integrated with spatially distributed piezoelectric actuator and sensor layers, is investigated based on the linear three dimensional exact piezo-elasticity theory. To assist control system design, system identification is conducted by applying a frequency domain subspace approximation method based on N4SID algorithm using the first few structural modes of the system. The state space model is constructed from system identification and used for state estimation and development of control algorithm. The optimal electrode configuration for the collocated piezoelectric actuator–sensor pair is found by applying a genetic optimization procedure based on maximization of a quantifiable objective function considering the controllability, observability and spillover prevention of the identified system. A linear quadratic Gaussian (LQG) optimal controller is subsequently designed and simulated based on the identified model of optimally configured smart structure in order to actively control the system response in both frequency and time domains. The dynamic performance and effectiveness of the optimized vibration control system is demonstrated for two different types of external mechanical excitations (i.e., impulsive load and white noise disturbance). The accuracy of dynamic analysis is established with the aid of a commercial finite element package and the data available in the literature.     

Constant thrust programming for a multistage rocket flown in vacuum with a given initial/final thrust-to-weight ratio in an arbitrary stage

The burn time and burnout velocity of a multistage rocket flown vertically in vacuum with constant thrust tangential to the flight path and a prescribed initial/final thrust-to-weight ratio in an arbitrary stage have been determined. The present paper also deals with optimal staging under given conditions of flight.     

The effects of gas flow rates on the etch characteristics of silicon nitride with an extreme ultra-violet resist pattern in CH2F2/N2/Ar capacitively coupled plasmas

The effects of CH₂F₂ and N₂ gas flow rates on the etch selectivity of silicon nitride (Si₃N₄) layers to extreme ultra-violet (EUV) resist and the variation of the line edge roughness (LER) of the EUV resist and Si₃N₄ pattern were investigated during etching of a Si₃N₄/EUV resist structure in dual-frequency superimposed CH₂F₂/N₂/Ar capacitive coupled plasmas (DFS-CCP). The flow rates of CH₂F₂ and N₂ gases played a critical role in determining the process window for ultra-high etch selectivity of Si₃N₄/EUV resist due to disproportionate changes in the degree of polymerization on the Si₃N₄ and EUV resist surfaces. Increasing the CH₂F₂ flow rate resulted in a smaller steady state CH_xF_y thickness on the Si₃N₄ and, in turn, enhanced the Si₃N₄ etch rate due to enhanced SiF₄ formation, while a CH_xF_y layer was deposited on the EUV resist surface protecting the resist under certain N₂ flow conditions. The LER values of the etched resist tended to increase at higher CH₂F₂ flow rates compared to the lower CH₂F₂ flow rates that resulted from the increased degree of polymerization.     

Improvement in thermoelectric properties of an n-type bismuth telluride (Bi2Se0.3Te2.7) due to texture development and grain refinement during hot deformation

Hot deformation of an n-type bismuth telluride (nBT of composition Bi₂Se_0.3Te_2.7) results in a texture characteristic of the deformation mode. Extruded nBT has a fiber texture with ?112?0? directions aligned with the extrusion direction. Rolling of previously textured (extruded) and untextured (sintered powder compact) material results in a rolling texture with the basal plane parallel to the rolling plane, and the ?112?0? directions randomly oriented on the rolling plane. Results indicate an improvement in thermoelectric figure of merit at 300 K from 0.79 in the as-received extruded material to 0.93 in the rolled material.     

Observation of thermal effects due to an optical incident signal and high fluence on InGaAs/InP multiple-quantum-well saturable absorber nonlinear mirrors: evolution of characteristics and time constants

We observe the effects of a temperature increase on the characteristics of an InGaAs/InP multiple-quantum-well (MQW) saturable absorber (SA) in a microcavity provided by an optical input signal under normal incidence. The temperature increase on the nonlinear mirror (NLM) due to an optical signal depends on the energy time filling factor (FF) of this input signal (analogous to the signal's duty cycle, which is the ratio between the repetition period and the pulse duration) and hence depends on the repetition rate of the signal for a given pulse time width. This increase in temperature is mostly responsible for a shift in the reflectivity spectrum of the device toward higher wavelengths. In this experimental study, we show the shift of the resonance cavity versus the optical input power at high FF, and we evaluate the thermal time constant of an Fe-doped InGaAs/InP MQW NLM. Finally, we report the consequences of such thermal effects and high fluence on the reflectivity and contrast of two different InGaAs/InP NLMs when the input signal FF rises up to 25%, which gets close to telecommunication transmission conditions.     

Prediction of rates of freezing,thawing or cooling in solids or arbitrary shape using the finite element methodPrévision des rapidités de congélation,de décongélation ou de refroidissement dans des solides de forme quelconque par la méthode des éléments finis

The finite element method was formulated for the solution of three dimensional heat transfer problems in solids of arbitrary geometry with variable thermal properties. These variable properties can include latent heat effects. The accuracy of the method was tested against available analytical solutions and against experimental data for freezing of regular shapes. The method gave comparable predictions to finite difference methods for similar problems and precision was therefore more limited by the data uncertainties than by the numerical approximations inherent in the method. A simplified formulation investigated gave only slightly reduced accuracy yet much shorter computation times than the general formulation. The computer codes for both formulations are available from the authors.The flexibility of the method allows application to a wide variety of situations. For example, rates of chilling, freezing or thawing food or other solids of any shape under any type of external heat transfer environment can be predicted, heterogeneous composition can be taken into account in these predictions, and simultaneous heat and mass transfer can be considered.