Алхазов, Артём Эдуардович — избранные публикации в Computer Science Journal of Moldova, Институт Математики и Информатики «Владимир Андрунакевич»
Artiom Alhazov, Rudolf Freund, Petr Sosík:
Small P Systems with Catalysts or Anti-Matter Simulating Generalized Register Machines and Generalized Counter Automata.
Computer Science Journal of Moldova 23, 3(69), 2015.
In this paper we focus on two weak forms of cooperation in P systems, namely, catalytic rules and matter/anti-matter annihilation rules. These variants of P systems both are computationally complete, while the corresponding rule complexity turns out to be of special interest. For establishing considerably small universal P systems in both cases, we found two suitable tools: generalized register machines and generalized counter automata. Depending on the features used in the different variants, we construct several small universal P systems.
Developments in Networks of Evolutionary Processors.
Computer Science Journal of Moldova 21, 1(61), 2013.
Networks of evolutionary processors (NEPs) are distributed word rewriting systems typically viewed as language generators. Each node contains a set of words, a set of operations (typically insertion, deletion or rewriting of one symbol with another one), an input filter and an output filter. The purpose of this paper is to overview existing models of NEPs, their variants and developments. In particular, besides the basic model, hybrid networks of evolutionary processors (HNEPs) have been extensively studied. In HNEPs, operations application might be restricted to specific end of the string, but the filters are random-context conditions (they were regular in the basic model). We will also cover the literature on the so-called obligatory HNEPs, i.e., ones where the operations are obligatory: the string that cannot be rewritten is not preserved. Some specific aspects that we pay attention to are: computational universality and completeness, the topology of the underlying graph, the number of nodes, the power of filters.
Artiom Alhazov, Marco Antoniotti, Rudolf Freund, Alberto Leporati, Giancarlo Mauri:
Self-Stabilization in Membrane Systems.
Computer Science Journal of Moldova 20, 2(59), 2012.
In this paper we study a notion of self-stabilization, inspired from biology and engineering. Multiple variants of formalization of this notion are considered, and we discuss how such properties affect the computational power of multiset rewriting systems.
Artiom Alhazov, Constantin Ciubotaru, Sergiu Ivanov, Yurii Rogozhin:
Membrane Systems Languages Are Polynomial-Time Parsable.
Computer Science Journal of Moldova 18, 2(53), 2010.
The focus of this paper is the family of languages generated by transitional non-cooperative P systems without further ingredients. This family can also be defined by so-called time yields of derivation trees of context-free grammars. In this paper we prove that such languages can be parsed in polynomial time, where the degree of polynomial may depend on the number of rules and on the size of the alphabet.
Minimal Parallelism and Number of Membrane Polarizations.
Computer Science Journal of Moldova 18, 2(53), 2010.
It is known that the satisfiability problem (SAT) can be efficiently solved by a uniform family of P systems with active membranes with two polarizations working in a maximally parallel way. We study P systems with active membranes without non-elementary membrane division, working in minimally parallel way. The main question we address is what number of polarizations is sufficient for an efficient computation depending on the types of rules used.
In particular, we show that it is enough to have four polarizations, sequential evolution rules changing polarizations, polarizationless non-elementary membrane division rules and polarizationless rules of sending an object out. The same problem is solved with the standard evolution rules, rules of sending an object out and polarizationless non-elementary membrane division rules, with six polarizations. It is an open question whether these numbers are optimal.
Artiom Alhazov, Elena Boian, Svetlana Cojocaru, Yurii Rogozhin:
Modelling Inflections in Romanian Language by P Systems with String Replication.
Computer Science Journal of Moldova 17, 2(50), 2009.
The aim of this article is the formalization of inflection process for the Romanian language using the model of P systems with cooperative string replication rules, which will make it possible to automatically build the morphological lexicons as a base for different linguistic applications.
Alhazov Artiom, Yurii Rogojin:
About Precise Characterization of Languages Generated by Hybrid Networks of Evolutionary Processors with One Node.
Computer Science Journal of Moldova 16, 3(48), 2008.
A hybrid network of evolutionary processors (an HNEP) is a graph where each node is associated with an evolutionary processor (a special rewriting system), a set of words, an input filter and an output filter. Every evolutionary processor is given with a finite set of one type of point mutations (an insertion, a deletion or a substitution of a symbol) which can be applied to certain positions of a string over the domain of the set of these rewriting rules. The HNEP functions by rewriting the words that can be found at the nodes and then re-distributing the resulting strings according to a communication protocol based on a filtering mechanism. The filters are defined by certain variants of random-context conditions. In this paper we complete investigation of HNEPs with one node and present a precise description of languages generated by them.
Artiom Alhazov, Yurii Rogozhin:
Generating Languages by P Systems with Minimal Symport/Antiport.
Computer Science Journal of Moldova 14, 3(42), 2006.
It is known that P systems with two membranes and minimal symport/antiport rules are “almost” computationally complete as generators of number or vector sets. Interpreting the result of the computation as the sequence of terminal symbols sent to the environment, we show that P systems with two membranes and symport rules of weight two or symport/antiport rules of weight one generate all recursively enumerable languages.
Artiom Alhazov, Manfred Kudlek, Yurii Rogozhin:
Nine Universal Circular Post Machines.
Computer Science Journal of Moldova 10, 3(30), 2002.
We consider a new kind of computational device like Turing machine, so-called circular Post machines with a circular tape and moving in one direction only, introduced recently by the second and the third authors. Using 2-tag systems we construct new nine small universal machines of this kind.
Alexandra Tkachenko, Artiom Alhazov:
The Multiobjective Bottleneck Transportation Problem.
Computer Science Journal of Moldova 9, 3(27), 2001.
In this paper we give the solution methods for a multicriterial transportation problem of a nonlinear type. We would like to note that the problems of this type do not have any classical solution algorithms.
The article consists of two parts dealing with 2 and 3 objectives respectively, one being non-linear of «bottleneck» type, and the rest being linear ones. Definitions of efficient and extreme efficient solutions are introduced and a separate solution algorithms for these models are described. The correctness theorems for the algorithms are proved. Examples solved by the computer programs implementing the algorithms are included.