Article
3 search hits
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Double and bordered alpha-circulant self-dual codes over finite commutative chain rings
(2008)
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Michael Kiermaier
Alfred Wassermann
- In this paper we investigate codes over finite commutative rings R, whose generator matrices are built from alpha-circulant matrices. For a non-trivial ideal I < R we give a method to lift such codes over R/I to codes over R, such that some isomorphic copies are avoided. For the case where I is the minimal ideal of a finite chain ring we refine this lifting method: We impose the additional restriction that lifting preserves self-duality. It will be shown that this can be achieved by solving a linear system of equations over a finite field. Finally we apply this technique to Z_4-linear double nega-circulant and bordered circulant self-dual codes. We determine the best minimum Lee distance of these codes up to length 64.
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On the benefits of using NP-hard problems in Branch & Bound
(2008)
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Jörg Rambau
Cornelius Schwarz
- We present a Brand-and-Bound (B&B) method using combinatorial bounds for solving makespan minimization problems with sequence dependent setup costs. As an application we present a laser source sharing problem arising in car manufacturing.
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Sprache, Diskurs und Gesundheit
(2008)
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Martina Drescher
- Im Zentrum des Beitrags stehen kommunikative Aspekte der HIV/AIDS-Prävention im subsaharischen Afrika. Ausgehend von der Heterogenität des Wissens über HIV/AIDS, die in der Existenz von unterschiedlichen, miteinander konkurrierenden Diskursen zum Ausdruck kommt, befasst sich der Beitrag insbesondere mit Problemen der Sprachenwahl sowie der Adressatenorientierung von Präventionskampagnen in mehrsprachigen Gesellschaften.
