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Initializing a model written in Modelica translates to finding consistent initial values to the underlying DAE. Adding initial equations and conditions creates a system of non-linear equations that can be solved for the initial configuration. This paper reports an implementation of Newton's method to solve the non-linear initialization system. This implementation also uses a regularization method
Downtimes in a manufacturing cell, line or individual machines are characterized by a stochastic behavior that their frequency and their duration display. A method is presented here for analyzing this dynamic behavior from a cost perspective. An important element of the method is statistical analysis of downtimes, including empirical distribution functions pertaining to downtimes of specific types
Due to the deregulation of the electricity market the power producers are forced to continuously investigate various means of maintaining/increasing their profits. Improving the electrical efficiency through hardware upgrades is probably the most commonly employed measure, although the interest for enhancements with regard to plant operation is on the rise. Plant operation improvement is often m
Styvmoderligt behandlat område. Undersökningar visar att vart tredje svenskt grundvattenprov är förorenat av växtskyddsmedel. Ändå övervakas bara fjorton procent av de svenska grundvattenförekomsterna. Sverige måste agera nu för att få kontroll över situationen, skriver nio forskare och experter.
Abstract Background: Many people with a visual impairment have only peripheral vision. However, there is limited knowledge of the peripheral optics of the eye and only some measurements are available in this field. Methods: We simulated the paths of peripheral rays through the eye by means of raytracing. Five programs were compared. The OSLO raytracing software proved to be not only the best one
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The field of phylogenomics has emerged during the last five years, as the number of fully or partially sequenced genomes has increased rapidly. Using whole genomes for phylogenetic studies greatly increases the accuracy of the trees determined, and can potentially resolve phylogenetic questions that could not be resolved bu studies using only a few gene sequences. In the current thesis selected p
This article explores the environmental impact of logistics service provider (LPS) activities in the light of increased customer priorities and the fragmentation of the industry. The research is based on a narrative literature review, an interview study, a case survey, and three in-depth case studies. A framework on sustainability challenges in supply chains derived from the literature is used to
