Platform Dependent Verification: On Engineering Verification Tools for 21st Century

The paper overviews recent developments in platform-dependent explicit-state LTL model checking.Comment: In Proceedings PDMC 2011, arXiv:1111.006

The diversity and evolution of pollination systems in large plant clades: Apocynaceae as a case study

Background and Aims Large clades of angiosperms are often characterized by diverse interactions with pollinators, but how these pollination systems are structured phylogenetically and biogeographically is still uncertain for most families. Apocynaceae is a clade of >5300 species with a worldwide distribution. A database representing >10 % of species in the family was used to explore the diversity of pollinators and evolutionary shifts in pollination systems across major clades and regions. Methods The database was compiled from published and unpublished reports. Plants were categorized into broad pollination systems and then subdivided to include bimodal systems. These were mapped against the five major divisions of the family, and against the smaller clades. Finally, pollination systems were mapped onto a phylogenetic reconstruction that included those species for which sequence data are available, and transition rates between pollination systems were calculated. Key Results Most Apocynaceae are insect pollinated with few records of bird pollination. Almost three-quarters of species are pollinated by a single higher taxon (e.g. flies or moths); 7 % have bimodal pollination systems, whilst the remaining approx. 20 % are insect generalists. The less phenotypically specialized flowers of the Rauvolfioids are pollinated by a more restricted set of pollinators than are more complex flowers within the Apocynoids + Periplocoideae + Secamonoideae + Asclepiadoideae (APSA) clade. Certain combinations of bimodal pollination systems are more common than others. Some pollination systems are missing from particular regions, whilst others are over-represented. Conclusions Within Apocynaceae, interactions with pollinators are highly structured both phylogenetically and biogeographically. Variation in transition rates between pollination systems suggest constraints on their evolution, whereas regional differences point to environmental effects such as filtering of certain pollinators from habitats. This is the most extensive analysis of its type so far attempted and gives important insights into the diversity and evolution of pollination systems in large clades

ABSTRACT JANUARY: SEARCH BASED ON SOCIAL INSECT BEHAVIOR

January\footnote{Named after January\ud Cooley, a contemporary artist that has painted insects. }\ud is a group of interacting stateless model checkers. Each agent\ud functions on a processor located on a super computer or a\ud network of workstations (NOW). The agent's search pattern is a semi-random walk\ud based on the behavior of the grey field slug (\emph{Agriolimax reticulatus}),\ud the house fly (\emph{Musca domestica}), and the black ant (\emph{Lassius niger}).\ud The agents communicate to lessen the amount of duplicate work being done.\ud Every algorithm has a memory threshold above which they search efficiently.\ud This threshold varies not only by model but also by algorithm. Janaury's threshold\ud is lower than the thresholds of other algorithms we compared it to

Efficient External-Memory Graph Search for Model Checking

Model checking problems suffer from state space explosion. State space explosion is the number of states in the graph increases exponentially with the number of variables in the state description. Searching the large graphs required in model checking requires an efficient algorithm. This dissertation explores several methods to improve an externalmemory search algorithm for model checking problems. A tool implementing these methods is built on top of the Murphi model checker. One improvement is a state cache for immediate detection leveraging the properties of state locality. A novel type of locality, intralayer locality is explained and shown to exist in a variety of search spaces. Another improvement, partial delayed duplicate detection, exploits interlayer locality to reduce search times. An automatic partitioning function is described that allows hash-based delayed duplicate detection to be used without domain knowledge of the state space. A phased delayed duplicate detection algorithm combining features of hash-based delayed duplicate detection and sorting-based delayed duplicate detection is explained and compared to the other methods

School of Nite

Texts by Peter Lamborn Wilson ; images by Nancy Goldringhttps://digitalcommons.montclair.edu/all_books/1090/thumbnail.jp

Guided model checking with a bayesian meta-heuristic

This paper presents a formal verification algorithm for finding errors in models of concurrent systems. The algorithm improves explicit guided model checking by applying the empirical Bayes method to revise heuristic estimates of the distance from a given state to an error state. Guided search using the revised estimates finds errors with less search effort than the original estimates. 1