The structural complexity of instances of computational problems has been an important research area in theoretical computer science in the last decades. Its success manifested itself in tree-width—a complexity measure for undirected graphs. Many practically relevant problems that are difficult in general, can be efficiently solved on graphs of bounded tree-width. For directed graphs, there are...

In classification learning experiments, test subjects are presented with objects which they must categorize. The correct categories, which are known to the experimenter, are functions of the characteristics (“dimensions”) of the objects, such as size, color, brightness, and saturation. The experiments measure the relative difficulty of learning different categorizations. One major factor which ...

We argue that the networks that can be constructed to represent ecosystems may inform us about the open-endedness of the evolutionary systems that underlie their dynamics. By adopting this approach we circumvent problems that arise from looking for open-endedness at the level of the organism, the more usual approach. We then examine various measures of ecosystem (niche web) complexity and propo...

Dr. Attila Grandpierre is currently a senior scientific researcher at the Konkoly Observatory of Hungarian Academy of Sciences. He obtained his degree of University Doctor in 1977 from the Eötvös Lóránd University, his academic degree candidate of physical sciences in 1984 from the Hungarian Academy of Sciences and continued his research at the Konkoly Observatory. Dr. Grandpierre's scientific ...

Visual complexity influences people's perception of, preference for, and behaviour toward many classes of objects, from artworks to web pages. The ability to predict people's impression of the complexity of different kinds of visual stimuli holds, therefore, great potential for many domains, basic and applied. Here we use edge detection operations and several image metrics based on image compre...

The process of gene assembly in ciliates is a fascinating example of programmed DNA manipulations in living cells. Macronuclear genes are split into coding blocks (called MDSs), shuffled and separated by non-coding sequences to form micronuclear genes. Assembling the coding blocks from micronuclear genes to form functional macronuclear genes is facilitated by an impressive in-vivo implementatio...

Kolmogorov complexity and Shannon entropy are conceptually different measures. However, for any recursive probability distribution, the expected value of Kolmogorov complexity equals its Shannon entropy, up to a constant. We study if a similar relationship holds for Rényi and Tsallis entropies of order α, showing that it only holds for α = 1. Regarding a time-bounded analogue relationship, we s...

In this study, three measures of temporal pattern complexity were compared with regard to their perceptual validity. The first measure, based on the work of Tanguiane (1993), uses the idea that a temporal pattern can be described in terms of (elaborations of) more simple patterns, which occur simultaneously at different levels. The second measure is based on the complexity measure for finite se...

The first attempts to evaluate quantitatively the complexity of a system have been related to complexity of cells, organisms, and humans. Fascinated by the complex nature of the living things, a group of young mathematical biologists applied in the 1950s the Shannon theory of communications 1 to assess the information content of the living matter. The analysis made by Rashewsky 4 provided the f...

The nature of concept learning is a core question in cognitive science. Theories must account for the relative difficulty of acquiring different concepts by supervised learners. For a canonical set of six category types, two distinct orderings of classification difficulty have been found. One ordering, which we call paradigm-specific, occurs when adult human learners classify objects with easil...