Adjunct hexagonal array token Petri nets and hexagonal picture languages

Adjunct Hexagonal Array Token Petri Net Structures (AHPN) are re- cently introduced hexagonal picture generating devices which extended the Hexag- onal Array Token Petri Net Structures . In this paper we consider AHPN model along with a control feature called inhibitor arcs and compare it with some ex- pressive hexagonal picture generating and recognizing models with respect to the generating power

Pure 2D picture grammars and languages

A new syntactic model, called pure two-dimensional (2D) context-free grammar (P2DCFG), is introduced based on the notion of pure context-free string grammar. The rectangular picture generative power of this 2D grammar model is investigated. Certain closure properties are obtained. An analogue of this 2D grammar model called pure 2D hexagonal context-free grammar (P2DHCFG) is also considered to generate hexagonal picture arrays on triangular grids

Computing with Membranes and Picture Arrays

Splicing systems were introduced by Tom Head [3] on biological considerations to model certain recombinant behaviour of DNA molecules. An effective extension of this operation to images was introduced by Helen Chandra et al. [5] and H array splicing systems were considered. A new method of applying the splicing operation on images of hexagonal arrays was introduced by Thomas et al. [12] and generated a new class of hexagonal array languages HASSL. On the other hand, P systems, introduced by Paun [6] generating rectangular arrays and hexagonal arrays have been studied in the literature, bringing together the two areas of theoretical computer science namely membrane computing and picture languages. P system with array objects and parallel splicing operation on arrays is introduced as a simple and effective extension of P system with operation of splicing on strings and this new class of array languages is compared with the existing families of array languages. Also we propose another P system with hexagonal array objects and parallel splicing operation on hexagonal arrays is introduced and this new class of hexagonal array languages is compared with the existing families of hexagonal array languages

Variants Of Array-Rewriting P Systems For Generating Picture Arrays

Bidang pengkomputeran membran dimulakan sekitar tahun 2000, berinspirasikan struktur dan fungsi sel-sel hidup. Model teori pengkomputeran membran ini dipanggil sistem P dan variannya dan penggunaan model ini dalam pelbagai masalah telah disiasat secara intensif sejak itu. Sistem P tatasusunan menghubungkan tatabahasa tatasusunan bahasa formal dengan sistem P. Dalam teori bahasa formal, salah satu kajian utama adalah terhadap keupayaan tatabahasa untuk menjana bahasa, yang disebut sebagai keupayaan generatif, yang bergantung kepada jenis-jenis peraturan yang digunakan. Kami menyiasat keupayaan generatif sistem P tatasusunan dengan memperkenalkan dalam peraturan sistem ciri-ciri benar, tatabahasa dengan penulisan semula selari dan kaedah mengumpul peraturan. Di sini dengan mengaitkan simbol benar dalam kaedah sistem P tatasusunan, kami memperkenalkan varian baru, yang dinamakan sebagai sistem P tatasusunan dengan ciri-ciri benar. Kami membuktikan bahawa jumlah membran yang digunakan dalam pembinaan itu dapat dikurangkan berbanding sistem P tatasusunan. Kami menggabungkan penulisan semula selari dalam sistem P rentetan di dalam sistem P tatasusuan, dengan itu memperkenalkan satu lagi varian baru dalam sistem P tatasusunan dan dinamakan sebagai sistem P tatasusunan selari. Inspired by the structure and functioning of the living cells, the field of membrane computing was initiated around the year 2000. Since then the theoretical model introduced in this area, called P system has been intensively investigated for properties and applications. One such P system known as array-rewriting P systems provides a link between two dimensional formal language theory and membrane computing. In formal language theory, one of the main studies is on the language generating capability of the grammars, referred to as the generative capacity, which depends on the types of rules. Also a standard technique to increase the generative capacity is to endow the rules with additional features. Here the array-rewriting P system is investigated by endowing the grammatical rules of the system with three such features, namely, permitting symbols, parallel rewriting and grouping of rules. Thus this thesis introduces and develops three such variants of the array-rewriting P system and brings out their advantages

Area distribution of the planar random loop boundary

We numerically investigate the area statistics of the outer boundary of planar random loops, on the square and triangular lattices. Our Monte Carlo simulations suggest that the underlying limit distribution is the Airy distribution, which was recently found to appear also as area distribution in the model of self-avoiding loops.Comment: 10 pages, 2 figures. v2: minor changes, version as publishe

Why Delannoy numbers?

This article is not a research paper, but a little note on the history of combinatorics: We present here a tentative short biography of Henri Delannoy, and a survey of his most notable works. This answers to the question raised in the title, as these works are related to lattice paths enumeration, to the so-called Delannoy numbers, and were the first general way to solve Ballot-like problems. These numbers appear in probabilistic game theory, alignments of DNA sequences, tiling problems, temporal representation models, analysis of algorithms and combinatorial structures.Comment: Presented to the conference "Lattice Paths Combinatorics and Discrete Distributions" (Athens, June 5-7, 2002) and to appear in the Journal of Statistical Planning and Inference

Variable 4: A Dynamical Composition for Weather Systems

Variable 4 is a multichannel sound installation that uses meteorological sensors and a multi-layered array of algorithmic processes to transform weather data into musical patterns in real time. This paper describes the work in detail, outlining its historical context, systems infrastructure and installation specifics. The piece is discussed in relation to sonification and environmental installation, and observations are made on the process of siting a complex sound work in the natural world

Randomly Generated 3D Environments for Serious Games

Abstract — This paper describes a variety of methods that can be used to create realistic, random 3D environments for serious games requiring real-time performance. These include the generation of terrain, vegetation and building structures. An interactive flight simulator has been created as proof of concept. An initial evaluation with two small samples of users (remote and hallway) revealed some usability issues but also showed that overall the flight simulator is enjoyable and appears realistic and believable. Keywords – serious games; 3D terrain modeling; computer graphics; flight simulator. I

Graph embedding in SYNCHEM2, an expert system for organic synthesis discovery

AbstractGraph embedding (subgraph isomorphism) is an NP-complete problem of great theoretical and practical importance in the sciences, especially chemistry and computer science. This paper presents positive test results for techniques to speed embedding by modeling graphs with subroutines, precalculating edge tables, turning recursion into iteration, and using search-ordering heuristics.The expert system synchem2 searches for synthesis routes of organic molecules without the online guidance of a user, and this paper examines how embedding information helps to implement the central operations of synchem2: selection, application, and evaluation of chemical reactions. The paper also outlines the architecture of synchem2, analyzes the computational time complexity of embedding and related problems in graph isomorphism and canonical chemical naming, and suggests topics and techniques for further research

Active Self-Assembly of Simple Units Using an Insertion Primitive

While computer science has given us a framework for determining the complexity and difficulty of solving computational problems, we do not yet have a theoretical framework for knowing what actions, behaviors, and life-like qualities can emerge from a given set of simple modular units. There has been much interest in developing models for programming active self-assembly processes in both the reconfigurable robotics community and the nanotechnology community. With respect to materials science and nanotechnology, the models proposed to date are either not yet implementable with our current understanding of synthetic chemistry or those that are implementable are limited to a set of features that do not capture the power of active components. Prior implementable models of molecular assembly only considered the passive behaviors of attaching and detaching from a complex. Inspired by the algorithmic tile assembly model [Winfree, 1996] and the graph grammar assembly model [Klavins et al., 2004], we describe a formal model for studying the complexity of self-assembled structures with active molecular components. In particular, we add an insertion primitive and we show a direct mapping of our model to a molecular implementation using DNA. We show that the expressive power of this language is stronger than regular languages, but at most as strong as context free grammars. Here, we explore the trade-off between the complexity of the system (in terms of the number of unit types), and the behavior of the system and speed of its assembly. We find that we can grow a line of any given length n in expected time O(log^3 n) using O(log^2 n) monomers. If we grow a line with k insertion rules, either the expected final length is infinite or the expected length at time t is at most (2t+2)^k^2, which is polynomial in t