Two-way nondeterministic pushdown automata (2PDA) are classical nondeterministic pushdown automata (PDA) enhanced with two-way motion of the input head. In this paper, the subclass of 2PDA accepting bounded languages and making at most a constant number of input head turns is studied with respect to descriptional complexity aspects. In particular, the effect of reducing the number of pushdown r...

In the history of cybernetics there have been several attempts by cyberneticians to put themselves into the circularities of their theories and designs, invoking a shift from the cybernetics of mechanisms to a cybernetics of cybernetics. The latter is the title of a book chapter by Margaret Mead (1968) and of Heinz von Foerster’s (1974) edited compilation of articles on cybernetics. Foerster in...

90 0740-7475/03/$17.00 © 2003 IEEE Copublished by the IEEE CS and the IEEE CASS IEEE Design & Test of Computers THE DESIGN AUTOMATION CONFERENCE has evolved from a small workshop where technologists exchanged ideas on using computers for designing artifacts as diverse as buildings and electronic circuits to a large event with a rich technical program coupled with a trade show and commercial pre...

ganglionic eminences within which the internal capsule In this issue of Neuron, a paper by Ming et al. (2001) forms, it is expressed in the eminentia thalami, the enshows that stimulation of action potentials can dramatitopeduncular nucleus, and the caudal ganglionic emically alter the turning responses of growth cones to nence, structures positioned near the more proximal attractive and repuls...

A new orchid species, Bulbophyllum pingnanense, is described and illustrated from Fujian, China. It is similar to Bulbophyllum brevipedunculatum and Bulbophyllum albociliatum in vegetative and floral morphology, but it can be distinguished from Bulbophyllum brevipedunculatum by having a longer dorsal sepal with longer white ciliate on margin, longer and lanceolate lateral sepals, and a glabrous...

Notation: In the sequel K is a field and Σn is the group of permutation over n elements. If A is an operad, then the K-vector space of n-ary operations is denoted as usual by A(n). Recall that if A is regular, then A(n) := An⊗KΣn, where An is the K-vector space of n-ary operations without permutations of the entries. We adopt Sweedler notation for binary cooperation ∆ on a K-vector space V and ...

Computational modelling of the heart tube during development reveals the interplay between tissue asymmetry and growth that helps our hearts take shape.