730 research outputs found

    The classical-quantum boundary for correlations: discord and related measures

    Full text link
    One of the best signatures of nonclassicality in a quantum system is the existence of correlations that have no classical counterpart. Different methods for quantifying the quantum and classical parts of correlations are amongst the more actively-studied topics of quantum information theory over the past decade. Entanglement is the most prominent of these correlations, but in many cases unentangled states exhibit nonclassical behavior too. Thus distinguishing quantum correlations other than entanglement provides a better division between the quantum and classical worlds, especially when considering mixed states. Here we review different notions of classical and quantum correlations quantified by quantum discord and other related measures. In the first half, we review the mathematical properties of the measures of quantum correlations, relate them to each other, and discuss the classical-quantum division that is common among them. In the second half, we show that the measures identify and quantify the deviation from classicality in various quantum-information-processing tasks, quantum thermodynamics, open-system dynamics, and many-body physics. We show that in many cases quantum correlations indicate an advantage of quantum methods over classical ones.Comment: Close to the published versio

    Intelligent shop scheduling for semiconductor manufacturing

    Get PDF
    Semiconductor market sales have expanded massively to more than 200 billion dollars annually accompanied by increased pressure on the manufacturers to provide higher quality products at lower cost to remain competitive. Scheduling of semiconductor manufacturing is one of the keys to increasing productivity, however the complexity of manufacturing high capacity semiconductor devices and the cost considerations mean that it is impossible to experiment within the facility. There is an immense need for effective decision support models, characterizing and analyzing the manufacturing process, allowing the effect of changes in the production environment to be predicted in order to increase utilization and enhance system performance. Although many simulation models have been developed within semiconductor manufacturing very little research on the simulation of the photolithography process has been reported even though semiconductor manufacturers have recognized that the scheduling of photolithography is one of the most important and challenging tasks due to complex nature of the process. Traditional scheduling techniques and existing approaches show some benefits for solving small and medium sized, straightforward scheduling problems. However, they have had limited success in solving complex scheduling problems with stochastic elements in an economic timeframe. This thesis presents a new methodology combining advanced solution approaches such as simulation, artificial intelligence, system modeling and Taguchi methods, to schedule a photolithography toolset. A new structured approach was developed to effectively support building the simulation models. A single tool and complete toolset model were developed using this approach and shown to have less than 4% deviation from actual production values. The use of an intelligent scheduling agent for the toolset model shows an average of 15% improvement in simulated throughput time and is currently in use for scheduling the photolithography toolset in a manufacturing plant

    Theoretical framework for quantum networks

    Full text link
    We present a framework to treat quantum networks and all possible transformations thereof, including as special cases all possible manipulations of quantum states, measurements, and channels, such as, e.g., cloning, discrimination, estimation, and tomography. Our framework is based on the concepts of quantum comb-which describes all transformations achievable by a given quantum network-and link product-the operation of connecting two quantum networks. Quantum networks are treated both from a constructive point of view-based on connections of elementary circuits-and from an axiomatic one-based on a hierarchy of admissible quantum maps. In the axiomatic context a fundamental property is shown, which we call universality of quantum memory channels: any admissible transformation of quantum networks can be realized by a suitable sequence of memory channels. The open problem whether this property fails for some nonquantum theory, e.g., for no-signaling boxes, is posed.Comment: 23 pages, revtex

    The Application of Zeeko Polishing Technology to Freeform Femoral Knee Replacement Component Manufacture

    Get PDF
    The purpose of this study was to develop an advanced 7-axis Computer Numerical Controlled (CNC) Polishing Machine from its successful original application of industrial optics manufacture into a process for the manufacture of femoral knee components to improve wear characteristics and prolong component lifetimes. It was indentified that the successful manufacture of optical components using a corrective polishing procedure to enhance their performance could be applied to femoral knee implant components. Current femoral knee implants mimic the natural shape of the joint and are freeform (no axis of symmetry) in nature hence an advanced CNC polishing machine that can follow the contours associated with such shapes could improve surface finish and conformity of replacement femoral knee bearing surfaces, leading to improved performance. The process involved generating machine parameters that would optimize the polishing procedure to minimize wear of materials used in femoral knee implant manufacture. Secondly a design of a Non-Uniform Refind B-Spline (NURBS) model for control of the Polishing Machine over the freeform contours of the femoral component. Completing the process involved development of a corrective polishing process that would improve form control of the components. Such developments would improve surface finish and conformity which are well documented contributors to wear and hence the lifeline of orthopaedic implants. By the means of comparison of this technique to that of a conventional finishing technique using pin-on-plate disc testing it was concluded that performance of the CNC polished components was an improvement on that of the conventional technique. In the case of form control their were slight indications through small decreases in peak to valley (PV) error that the process helped reduce form error and could increase the lifetime of femoral knee replacement components. The overall study provided results that indicate the the Zeeko process could be used in the application of polishing of hard-on-hard material combinations to improve form control without compromising surface finish hence improving lifetimes of the implant. The results have their limitations in the fact that the wear test performance was only carried out on orthopaedic implant materials using a pin-on-plate wear test rig. Due to the time limitations on the thesis it can be said that further analysis of correcting form without compromising surface finish on entire implant systems under full joint simulator testing which would provide mre realistic contitions would a more definitive answer be achieved

    Factor Selection in Drilling Unidirectional Carbon Fiber Reinforced Plastic Composite Plates with The HSS Drill Bit Using Analytic Hierarchy Process

    Get PDF
    The present state of competition within the plastic composite industry calls for efficiency to be competitive. However, in the drilling of carbon-fiber-reinforced plastic (CFRP) composites, the process engineer still lacks knowledge of the priority of parameters as parameters are chosen at random, and resources are deployed without justification on their importance and strength. Consequently, production crises and productivity losses persist. In this article, the analytic hierarchy process (AHP) method is deployed to evaluate the weights of criteria in a CFRP composite drilling operation. The establishment of the decision, alternatives, and criteria is accomplished, and pairwise comparisons are conducted to allow the computation of the importance weight of each criterion. The weight is then established. The proposed approach was illustrated with experimental data from the literature with a plastic drilling case. Six criteria were chosen as crucial in determining the drilling parameters of CFRP composites. The results reveal the following: thrust force (0.413), torque (0.253), eccentricity (0.151), surface roughness (0.115), delamination at entry (0.037) and delamination at exit (0.030). In a validation exercise to ascertain the consistency of the analysis, a consistent analysis was obtained. The novelty of the article is using the AHP approach on the drilling of CFRP composites. Practically, these results impact operator training, indicating that attention should be focused on thrust force control. The industrial applications of CFRP composites include the basic structures of automobiles, ships, and airplanes
    • …
    corecore