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Design patterns from biology for distributed computing
 ACM TRANS. AUTON. ADAPT. SYST
, 2006
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On Synchronization in P Systems
"... The P systems were recently introduced as distributed parallel computing models of a biochemical type. Multisets of objects are placed in a hierarchical structure of membranes and they evolve according to given rules, which are applied in a synchronous manner: at each step, all objects which can ..."
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Cited by 31 (3 self)
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The P systems were recently introduced as distributed parallel computing models of a biochemical type. Multisets of objects are placed in a hierarchical structure of membranes and they evolve according to given rules, which are applied in a synchronous manner: at each step, all objects which can evolve, from all membranes, must evolve. We consider here the case when this restriction is removed. As expected, unsynchronized systems (even using catalysts) are weaker than the synchronized ones, providing that no priority relation among rules is considered. The power of P systems is not diminished when a priority is used and, moreover, the catalysts can change their states, among two possible states for each catalyst.
From cells to computers: Computing with membranes (P systems
 Biosystems
, 2001
"... The aim of this paper is to introduce to the reader the main ideas of computing with membranes, a recent branch of (theoretical) molecular computing. In short, in a celllike system, multisets of objects evolve according to given rules in the compartments defined by a membrane structure and compute ..."
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Cited by 29 (0 self)
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The aim of this paper is to introduce to the reader the main ideas of computing with membranes, a recent branch of (theoretical) molecular computing. In short, in a celllike system, multisets of objects evolve according to given rules in the compartments defined by a membrane structure and compute natural numbers as the result of halting sequences of transitions. The model is parallel, nondeterministic. Many variants have already been considered and many problems about them were investigated. We present here some of these variants, focusing on two central classes of results: (1) characterizations of the recursively enumerable sets of numbers and (2) possibilities to solve NPcomplete problems in polynomial — even linear — time (of course, by making use of an exponential space). The results are given without proofs. An almost complete bibliography of the domain, at the middle of October 2000, is
Solving NP Complete Problems Using P Systems with Active Membranes
 Unconventional Models of Computation
, 2000
"... A variant of P systems, recently introduced, considers membranes which can multiply by division. Two types of division are considered: division for elementary membranes (i.e. membranes not containing other membranes inside) and division for nonelementary membranes. In two recent papers it is shown ..."
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Cited by 25 (6 self)
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A variant of P systems, recently introduced, considers membranes which can multiply by division. Two types of division are considered: division for elementary membranes (i.e. membranes not containing other membranes inside) and division for nonelementary membranes. In two recent papers it is shown how to solve the Satisfiability problem and the Hamiltonian Path problem (two well known NP complete problems) in linear time with respect to the input length, using this variant of P systems. We show in this paper that P systems with division for elementary membranes only suffice to solve these two problems in linear time. What about the possibility of solving NP complete problems in polynomial time using P systems without membrane division? We show, moreover, that (if P 6= NP ) Deterministic P Systems without membrane division are not able to solve NP complete problems in polynomial time.
Membrane Systems with Symport/Antiport: Universality Results
 in Membrane Computing. Intern. Workshop WMCCdeA2002, Revised Papers
, 2002
"... We consider tissue P systems using symport / antiport rules of only one symbol where in each link (channel) between two cells at most one rule is applied, but in each channel a symport / antiport rule has to be used if possible. We prove that any recursively enumerable set of kdimensional vectors o ..."
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Cited by 19 (7 self)
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We consider tissue P systems using symport / antiport rules of only one symbol where in each link (channel) between two cells at most one rule is applied, but in each channel a symport / antiport rule has to be used if possible. We prove that any recursively enumerable set of kdimensional vectors of natural numbers can be generated (accepted) by such a tissue P system with symport / antiport rules of one symbol using at most 2k + 5 (at most 3k + 7) cells.
On the computational power of spiking neural P systems
 Inter. J.Unconventional Computing
"... Summary. In this paper we study some computational properties of spiking neural P systems. In particular, we show that by using nondeterminism in a slightly extended version of spiking neural P systems it is possible to solve in constant time both the numerical NP–complete problem Subset Sum and the ..."
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Cited by 16 (4 self)
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Summary. In this paper we study some computational properties of spiking neural P systems. In particular, we show that by using nondeterminism in a slightly extended version of spiking neural P systems it is possible to solve in constant time both the numerical NP–complete problem Subset Sum and the strongly NP–complete problem 3SAT. Then, we show how to simulate a universal deterministic spiking neural P system with a deterministic Turing machine, in a time which is polynomial with respect to the execution time of the simulated system. Surprisingly, it turns out that the simulation can be performed in polynomial time with respect to the size of the description of the simulated system only if the regular expressions used in such a system are of a very restricted type. 1
Membrane operations in P systems with active membranes
 SEVILLA UNIVERSITY
, 2004
"... In this paper we define a general class of P systems covering some biological operations with membranes, including evolution, communication, modifying the membrane structure, and we describe and formally specify some of these operations: membrane merging, membrane separation, membrane release. We al ..."
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Cited by 15 (4 self)
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In this paper we define a general class of P systems covering some biological operations with membranes, including evolution, communication, modifying the membrane structure, and we describe and formally specify some of these operations: membrane merging, membrane separation, membrane release. We also investigate a particular combination of types of rules that can be used in solving SAT problem in linear time.
Symport/antiport P systems with three objects are universal
 FUNDAMENTA INFORMATICAE
, 2005
"... The operations of symport and antiport, directly inspired from biology, are already known to be rather powerful when used in the framework of P systems. In this paper we confirm this observation with a quite surprising result: P systems with symport/antiport rules using only three objects can simul ..."
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Cited by 12 (0 self)
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The operations of symport and antiport, directly inspired from biology, are already known to be rather powerful when used in the framework of P systems. In this paper we confirm this observation with a quite surprising result: P systems with symport/antiport rules using only three objects can simulate any counter machine, while systems with only two objects can simulate any blind counter machine. In the first case, the universality (of generating sets of numbers) is obtained also for a small number of membranes, four.
RiscosNúñez: Tissue P System with cell division
 Second Brainstorming Week on Membrane Computing, Sevilla, Report RGNC 01/2004
"... Abstract. In tissue P systems several cells (elementary membranes) communicate through symport/antiport rules, thus carrying out a computation. We add to such systems the basic feature of (cell) P systems with active membranes – the possibility to divide cells. As expected (as it is the case for P s ..."
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Cited by 11 (1 self)
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Abstract. In tissue P systems several cells (elementary membranes) communicate through symport/antiport rules, thus carrying out a computation. We add to such systems the basic feature of (cell) P systems with active membranes – the possibility to divide cells. As expected (as it is the case for P systems with active membranes), in this way we get the possibility to solve computationally hard problems in polynomial time; we illustrate this possibility with SAT problem. 1