Ana Salagean

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Let R be a finite chain ring (e.g. a Galois ring), K its residue field and C a linear code over R. We prove that d(C), the Hamming distance of C, is d((C : α)), where (C : α) is a submodule quotient, α is a certain element of R and denotes the canonical projection to K. These two codes also have the same set of minimal codeword supports. We explicitly(More)
We consider the problem of computing a linear recurrence relation (or equivalently a linear feedback shift register) of minimum order for a finite sequence over a field, with the additional requirement that not only the highest but also the lowest coefficient of the recurrence is nonzero. Such a recurrence relation can then be used to generate the sequence(More)
We show that repeated-root cyclic codes over a finite chain ring are in general not principally generated. Repeated-root negacyclic codes are principally generated if the ring is a Galois ring with characteristic a power of 2. For any other finite chain ring they are in general not principally generated. We also prove results on the structure, cardinality(More)
The linear Games-Chan algorithm for computing the linear complexity c(s) of a binary sequence s of period lscr=2<sup>n</sup> requires the knowledge of the full sequence, while the quadratic Berlekamp-Massey algorithm requires knowledge of only 2c(s) terms. We show that we can modify the Games-Chan algorithm so that it computes the complexity in linear time(More)
Genetic algorithms (GAs) have been applied to solve the 2-page crossing number problem successfully, but since they work with one global population, the search time and space are limited. Parallelisation provides an attractive prospect to improve the efficiency and solution quality of GAs. This paper investigates the complexity of parallel genetic(More)
The simplest graph drawing method is that of putting the vertices of a graph on a line (spine) and drawing the edges as half-circles on k half planes (pages). Such drawings are called k-page book drawings and the minimal number of edge crossings in such a drawing is called the k-page crossing number. In a one-page book drawing, all edges are placed on one(More)
Genetic algorithms have been applied to solve the 2-page drawing problem successfully, but they work with one global population, so the search time and space are limited. Parallelization provides an attractive prospect in improving the efficiency and solution quality of genetic algorithms. One of the most popular tools for parallel computing is Message(More)