Chapter 15 – Geometric Shortest Paths and Network Optimization

http://profs.scienze.univr.it/~manca/mnc/membrane.pdf

A guide to membrane computing

Proceedings of world academy of science, engineering and technology, vol 8

Investigations into Drosophila Wing Development - Results from a Lindenmayer Model.- Fibonacci Words - A Survey.- Planar Map Generation by Parallel Binary Fission/Fusion Grammars.- Modular Trellises.- A New Proof for the DOL Sequence Equivalence Problem and its Implications.- On Compound Lindenmayer Systems.- Graph Grammars with Application Conditions.- The ETOL Hierarchy is in the OI Hierarchy.- Polyhedral Cell Shapes.- On Cyclically Overlap-Free Words in Binary Alphabets.- The Theoretical Basis of the Transplantation Experiment.- Fixed and Stationary ?-Words and ?-Languages.- DOL Schemes and Recurrent Words.- Stochastic OL Systems and Formal Power Series.- Complexity of L-Systems.- Compartmental Hybrid State Production-Diffusion Systems with Application to Prestalk-Prespore Pattern Regulation in Cellular Slime Molds.- Hierarchical Aspects of Plant Development.- Rule Trees Represent Derivations in Edge Replacement Systems.- Languages Defined by Indian Parallel Systems.- L Systems and NLOG-Reductions.- The Parikh-Boundedness of ETOL Languages of Finite Index.- Computer Networks with Compact Routing Tables.- Unconventional Leaves.- A Uniform Model for the Growth of Biological Organisms: Cooperating Sequential Processes.- Graph Technology Applied to a Software Project.- Some Systems for Map Generation.- A Programming Language for Lindenmayer Systems.- A Note on Significance of Cellular Interaction in L-System.- EOL Grammars and Search Trees.- Variation in Inflorescence Structure in Cotoneaster Franchetti.- Partial Path Groups and Parallel Graph Contractions.- When L was Young.- Equivalence Problems for Regular Sets of Word Morphisms.- Parentheses Grammars and Lindenmayer Grammars.- Array Languages and Lindenmayer Systems - A Survey.- Symmetric Distributed Termination.- Development, Growth and Time.- On the Set of all Subgraphs of the Graphs in a Boundary NLC Graph Language.- Graph-Controlled Systems - An Extension of OL Systems.

The Book of L

This is a comprehensive (and friendly) introduction to membrane computing (MC), meant to offer both computer scientists and non-computer scientists an up-to-date overview of the field. That is why the set of notions introduced here is rather large, but the presentation is informal, without proofs and with rigorous definitions given only for the basic types of P systems — symbol object P systems with multiset rewriting rules, systems with symport/antiport rules, systems with string objects, tissue-like P systems, and neural-like P systems. Besides a list of (biologically inspired or mathematically motivated) ingredients/features which can be used in systems of these types, we also mention a series of results, as well as a series of research trends and topics.

/pdf/introduction-to-membrane-computing-5cngwvz0yk.pdf

Introduction to Membrane Computing

Gene insertion and deletion are the operations that occur commonly in DNA processing and RNA editing. Based on these evolutionary transformations, a computing model has been formulated in formal language theory known as insertion-deletion systems. In this paper, we study about the ambiguity issues of insertion systems. First, we define six levels of ambiguity for insertion systems based on the components used in the derivation such as axiom, contexts and strings. Next, we show that there are inherently i-ambiguous insertion languages which are j-unambiguous for the combinations (i, j) ∈ {(5,0), (5,4), (4,3), (4,2), (3,1),(2,1), (1,0), (0,1)}. Finally, we prove an important result that the ambiguity problem of insertion systems is undecidable.

On the ambiguity of insertion systems

Tree automata have been defined to accept trees. Different types of acceptance like bottom-up, top-down, tree walking have been considered in the literature. In this paper, we consider bottom-up tree automata and discuss the sequential distributed version of this model. Generally, this type of distribution is called cooperative distributed automata or the blackboard model. We define the traditional five modes of cooperation, viz. ∗-mode, t-mode, = k, ≥ k, ≤ k (k ≥ 1) modes on bottom-up tree automata. We discuss the accepting power of cooperative distributed tree automata under these modes of cooperation. We find that the ∗- mode does not increase the power, whereas the other modes increase the power. We discuss a few results comparing the acceptance power under different modes of cooperation.

/pdf/on-the-power-of-distributed-bottom-up-tree-automata-11behrjb42.pdf

On The Power of Distributed Bottom-up Tree Automata

We propose a new type of regulation on the derivation of a context-free grammar: the productions used for passing from a level of a derivation tree to the next level should have the right-hand members of the same length. We prove that such length synchronized context-free grammars characterize the family of ETOL languages, and therefore are equivalent with the synchronization context-free grammars of H. Juirgensen and K. Salomaa. In this way, a conjecture of H. Jurgensen and K. Salomaa is disproved, about a language which was conjectured not to be generated by a synchronization context-free grammar.

Length synchronization context-free grammars

We consider the problem of separating a collection of isothetic polygons in the plane by translating one polygon at a time to infinity. The directions of translation are the four isothetic (parallel to the axes) directions, but a particular polygon can be translated only in one of these four directions. Our algorithm detects whether a set is separable in this sense and computes a translational ordering of the polygons. The time and space complexities of our algorithm is Θ(n log n) and Θ(n) respectively, where n is the total number of edges of the polygons in the set. The best previous algorithm in the plane for this problem had complexities of O(n log2n) time and O(n log n) space.

An Optimal Algorithm for One-Separation of a Set of Isothetic Polygons

The aim of this paper is to study the reconstruction of binary images from two projections using a priori images that are similar to the unknown image. Reconstruction of images from a few projections is preferred to reduce radiation hazards. It is well known that the problem of reconstructing images from a few projections is ill-posed. To handle the ill-posedness of the problem, a priori information such as convexity, connectivity and periodicity are used to limit the number of possible solutions. We use a priori images that are similar to the unknown image, to reduce the class of images having the same two projections. The a priori similar images may be obtained in many ways such as by considering images of neighboring slices or images of the same slice, taken in previous time instances. In this paper, we give a polynomial time algorithm to reconstruct binary image from two projections such that the reconstructed image is optimally close to the a priori similar images. We obtain a solution to our problem by reducing our problem to min cost integral max flow problem.

Kamala Krithivasan

Papers

On the ambiguity of insertion systems

On The Power of Distributed Bottom-up Tree Automata

Length synchronization context-free grammars

An Optimal Algorithm for One-Separation of a Set of Isothetic Polygons

A min-cost-max-flow based algorithm for reconstructing binary image from two projections using similar images