Effective use of product quality information in meat processing

This paper presents a case study on use of advanced product quality information in meat processing. To serve segmented customer demand meat processors consider use of innovative sensor technology to sort meat products to customer orders. To assess the use of this sensor technology a discrete-event simulation model is built. Various scenarios were defined for processing strategy (buffered or non-buffered), the number of end product groups to sort to and the availability of product quality information. The performance of these scenarios is measured w.r.t. order compliance, labor consumption and throughput-time. Our results reveal that the current processing and product sorting strategy is in-effective for sorting to a large number of end product groups. Furthermore, the current availability of product quality information is insufficient to ensure high levels of order compliance for advanced product quality products

A comparative study of numerical methods for the overlap Dirac operator--a status report

Improvements of various methods to compute the sign function of the hermitian Wilson-Dirac matrix within the overlap operator are presented. An optimal partial fraction expansion (PFE) based on a theorem of Zolotarev is given. Benchmarks show that this PFE together with removal of converged systems within a multi-shift CG appears to approximate the sign function times a vector most efficiently. A posteriori error bounds are given.Comment: 3 pages, poster contribution to Lattice2001(algorithms

Differences in the effects of rouding errors in Krylov solvers for symmetric indefinite linear systems

The three­term Lanczos process for a symmetric matrix leads to bases for Krylov subspaces of increasing dimension. The Lanczos basis, together with the recurrence coe#cients, can be used for the solution of symmetric indefinite linear systems, by solving a reduced system in one way or another. This leads to well­known methods: MINRES (minimal residual), GMRES (generalized minimal residual), and SYMMLQ (symmetric LQ). We will discuss in what way and to what extent these approaches di#er in their sensitivity to rounding errors. In our analysis we will assume that the Lanczos basis is generated in exactly the same way for the di#erent methods, and we will not consider the errors in the Lanczos process itself. We will show that the method of solution may lead, under certain circumstances, to large additional errors, which are not corrected by continuing the iteration process. Our findings are supported and illustrated by numerical examples

Thought for Food: the impact of ICT on agribusiness

This report outlines the impact of ICT on the food economy. On the basis of a literature review from four disciplines - knowledge management, management information systems, operations research and logistics, and economics - the demand for new ICT applications, the supply of new applications and the match between demand and supply are identified. Subsequently the impact of new ICT applications on the food economy is discussed. The report relates the development of new technologies to innovation and adoption processes and economic growth, and to concepts of open innovations and living lab

Shear viscosity of an ordering latex suspension

The shear viscosity of a latex which is ordered at rest is studied as a function of the shear rate and volume fraction. At low shear rates and for moderate to high volume fractions, the flow curves show dynamic yield behavior which disappears below a volume fraction of 8%. At high shear rates, the onset to the high shear rate plateau of the viscosity can be observed. A new model for the shear viscosity for lattices at high volume fractions is described. This model is based upon theories for the shear viscosity of dilute lattices of Blachford et al. [J. Phys. Chem. 73, 1062 (1969)] and Russel [J. Fluid Mech. 85, 673 (1978)]. In terms of this model, the ordered latex is broken down under shear flow into ordered domains suspended in a disordered fluid. The larger the shear rate, the smaller the volume fraction of ordered domains. The experimental results can be described reasonably well with the model discussed here

Numerical Methods for the QCD Overlap Operator: I. Sign-Function and Error Bounds

The numerical and computational aspects of the overlap formalism in lattice quantum chromodynamics are extremely demanding due to a matrix-vector product that involves the sign function of the hermitian Wilson matrix. In this paper we investigate several methods to compute the product of the matrix sign-function with a vector, in particular Lanczos based methods and partial fraction expansion methods. Our goal is two-fold: we give realistic comparisons between known methods together with novel approaches and we present error bounds which allow to guarantee a given accuracy when terminating the Lanczos method and the multishift-CG solver, applied within the partial fraction expansion methods.Comment: 30 pages, 2 figure