Das Spektrum des Gelenkvierecks bei veränderlicher Gestell-Länge

Zusammenfassung Das Gelenkviereck kann man am einfachsten durch Lagen?nderungen eines Gestellpunkts, d. h. durch ?ndern der Gestell-L?nge unter Beibehaltung der L?ngen aller übrigen Glieder verstellen. Dadurch entstehen bei voller Ausnutzung der Gestell-L?ngen?nderung verschiedene Formen des Gelenkvierecks, die sich durch die Art der Relativbewegungen benachbarter Glieder als umlaufende oder nur schwingende Bewegungen unterscheiden. In r?umlichen Schaubildern lassen sich s?mtliche Bereiche des Gelenkvierecks umfassend darstellen. Mitteilung aus dem Institut für landtechnische Grundlagenforschung der Forschungsanstalt für Landwirtschaft, Braunschweig-V?lkenrode. Die Untersuchungen bilden einen Teil eines von der Deutschen Forschungsgemeinschaft gef?rderten Programms zum Erstellen verschiedener Gruppen von Kurventafeln für ungleichf?rmig übersetzende Getriebe.     

Uncertainty in biomass supply estimates: Lessons from a Yakama Nation case study

The increasing demand for bioenergy in the United States necessitates detailed case studies of cost and supply to assess its feasibility. We have developed supply curves based on six feedstocks in five counties surrounding the Yakama Nation in central Washington using spatially explicit estimates of supply and transportation cost. The supply curves were used to examine a base case supply for a bioenergy plant, to analyze the effects of land ownership, and examine the impacts of uncertainty in parameters used to determine cost and supply. The results show that existing industries produce the cheapest supply of feedstock as a byproduct of their operations, while supplies harvested specifically for bioenergy are considerably more expensive. Fragmented land ownerships lead to the necessity of cooperation between owners and highlight the importance of a strong anchor supply close to the plant. Lastly, uncertainty in supply and cost parameters leads to larger ranges in available biomass, leading to reluctant investment in large plants.     

Attacks and Defenses for JTAG

Editor's note:JTAG is a well-known standard mechanism for in-field test. Although it provides high controllability and observability, it also poses great security challenges. This article analyzes various attacks and proposes protection schemes.—Mohammad Tehranipoor, University of Connecticut     

A Framework for the Verification of Certifying Computations

Formal verification of complex algorithms is challenging. Verifying their implementations goes beyond the state of the art of current automatic verification tools and usually involves intricate mathematical theorems. Certifying algorithms compute in addition to each output a witness certifying that the output is correct. A checker for such a witness is usually much simpler than the original algorithm—yet it is all the user has to trust. The verification of checkers is feasible with current tools and leads to computations that can be completely trusted. We describe a framework to seamlessly verify certifying computations. We use the automatic verifier VCC for establishing the correctness of the checker and the interactive theorem prover Isabelle/HOL for high-level mathematical properties of algorithms. We demonstrate the effectiveness of our approach by presenting the verification of typical examples of the industrial-level and widespread algorithmic library LEDA.