Thomas Worsch's research while affiliated with Karlsruhe Institute of Technology and other places

... In the one-dimensional setting, one possibility is that states are updated sequentially during a left-to-right (or right-toleft) sweep across the entire infinite line of cells. Such a setup is studied in [93] where the update performed once in each position is given by a reversible block rule A n −→ A n on n consecutive cells. The authors give a precise characterisation of the one-dimensional cellular automata that can be realised by such a sweep. ...

... Combining them yields the shrinking and expanding CA (SXCA). The polynomial-time class of SXCA language deciders was shown to coincide with PSPACE (Modanese 2016; Modanese and Worsch 2016). ...

... They are useful when trying to diagnose application performance issues as they often report the average time for MPI operations. SKaMPI is no longer under active development but was extended to cater for complex communication patterns [15]. ...

... A straightforward method is to simulate a synchronous CA on an ACA via a mechanism that makes cells run in lockstep on a local scale [21,7,13], but it comes at the expense of a large overhead in cell states and transition rules. Less overhead will ensue by the direct embedding of logic circuits into cell spaces [23,24,12,15,27], but even then there is an increase in the complexities of ACAs. For example, one of Banks' synchronous cellular automata [2] employs 2 cell states and 3 rules to conduct universal computation, whereas an efficient ACA model in [12] with the same (von Neumann) neighborhood as Banks' CA requires 5 cell states and 55 rules. ...

... Hence, the automaton is (k + 1)-reversible. As shown in [8,Theorem 4] we cannot do better for this language, i.e., L ∈ REV k+1 \ REV k . This can be also obtained as a consequence of results in Section 5. ...

... In the case where one is allowed to choose freely the order of update of the cells, it was shown that there are some rules which allow one to return to the initial condition and some that do not always allow this [DSS12,SMD12]. With a different perspective, Worsch and Wacker examined how to construct an "inverse" rule, in the sense that its transition graph would be the "inverse" of the transition graph of the original inverse [WW13]. The design of asynchronous circuits with reversible gates is also a current important topic of research (see e.g. ...

... This benchmarking approach is fundamentally different from above, but can lead to important outcomes that contribute to better application communication performance. The Special Karlsruhe MPI benchmark (SKaMPI) was created to benchmark MPI communications for supercomputer users and system administrators who want to tune their MPI libraries [12], evaluate and chose algorithms for collective communications [25,26], and ensure performance portability of the MPI library across platforms [17]. ...

... These automata can be seen as finite automata whose state graphs are undirected. So, this notion is even stronger than the concept of time-symmetry studied in [3,11]. Time-symmetry appears in physics when a system can go back in time by applying the same transition function as for forward computations after a weak transformation of the phase-space. ...

... One recent model of self-assembly is Tile Automata [9]. This model marries the concept of state changes from Cellular Automata [21,30,39] and the assembly process from the 2-Handed Assembly model (2HAM) [7]. Previous work [4,8,9] explored Tile Automata as a unifying model for comparing the relative powers of different Tile Assembly models. ...

... Cellular automata (CA) are mathematical discrete structures that are defined by an array of cells, each having a state that evolves in time. They were first introduced by Stanislaw Ulam et al in the 1940s [1], but much later in the 1980s was when they were studied deeply [2,4] in terms of their computational power, data parallelism, thermodynamics etc. Cellular automata have been a recent area of interest in research in the field of theory of computation [8,9,10,11,12,13], cryptography [3,14], traffic flow theory [5], parallel computation [5,6,7] and many more. Certain classes of CA have been known to be generating pseudorandom patterns [2,3,4] and as a specific example, the class 4 one dimensional CA [4] have known to generate spatio-temporally local patterns that interact in complex ways and survive for a long time. ...