Time-free Solution to Independent Set Problem using P Systems with Active Membranes

Membrane computing is a branch of natural computing aiming to abstract computing models from the structure and functioning of living cells. The computation models obtained in the field of membrane computing are usually called P systems. P systems have been used to solve computationally hard problems efficiently on the assumption that the execution of each rule is completed in exactly one time-unit (a global clock is assumed for timing and synchronizing the execution of rules). However, in biological reality, different biological processes take different times to be completed, which can also be influenced by many environmental factors. In this work, with this biological reality, we give a time-free solution to independent set problem using P systems with active membranes, which solve the problem independent of the execution time of the involved rules.

On the power of P systems with active membranes using weak non-elementary membrane division

It is known that polarizationless P systems with active membranes can solve $$\mathrm {PSPACE}$$ PSPACE -complete problems in polynomial time without using in-communication rules but using the classical (also called strong) non-elementary membrane division rules. In this paper, we show that this holds also when in-communication rules are allowed but strong non-elementary division rules are replaced with weak non-elementary division rules, a type of rule which is an extension of elementary membrane divisions to non-elementary membranes. Since it is known that without in-communication rules, these P systems can solve in polynomial time only problems in $$\mathrm {P}^{\text {NP}}$$ P NP , our result proves that these rules serve as a borderline between $$\mathrm {P}^{\text {NP}}$$ P NP and $$\mathrm {PSPACE}$$ PSPACE concerning the computational power of these P systems.

Factual power loss reduction by dynamic membrane evolutionary algorithm

<p class="papertitle">This paper presents Dynamic Membrane Evolutionary Algorithm (DMEA) has been applied to solve optimal reactive power problem.Proposed methodology merges the fusion and division rules of P systems with active membranes and with adaptive differential evolution (ADE), particle swarm optimization (PSO) exploration stratagem. All elementary membranes are amalgamated into one membrane in the computing procedure. Furthermore, integrated membrane are alienated into the elementary membranes 1, 2,_ m. In particle swarm optimization (PSO) 𝑪_𝟏, 𝑪_𝟐 (acceleration constants) are vital parameters to augment the explorationability of PSO in the period ofthe optimization procedure.In this work, Gaussian probability distribution isinitiated to engenderthe accelerating coefficients of PSO.Proposed Dynamic Membrane Evolutionary Algorithm (DMEA) has been tested in standard IEEE 14, 30, 57, 118, 300 bus test systems and simulation results show the projected algorithm reduced the real power loss comprehensively.</p>

Alternative space definitions for P systems with active membranes

The first definition of space complexity for P systems was based on a hypothetical real implementation by means of biochemical materials, and thus it assumes that every single object or membrane requires some constant physical space. This is equivalent to using a unary encoding to represent multiplicities for each object and membrane. A different approach can also be considered, having in mind an implementation of P systems in silico; in this case, the multiplicity of each object in each membrane can be stored using binary numbers, thus reducing the amount of needed space. In this paper, we give a formal definition for this alternative space complexity measure, we define the corresponding complexity classes and we compare such classes both with standard space complexity classes and with complexity classes defined in the framework of P systems considering the original definition of space.

POWDER CONSOLIDATION USING TECHNOLOGICAL COMBUSTION FOR DEVELOPMENT OF CATALYTICALLY ACTIVE MEMBRANES FOR HYDROCARBON DEHYDROGENATION

The work is devoted to the preparation of catalytically active membranes for the dehydrogenation of ethylbenzene to produce styrene which is necessary for the synthesis of numerous types of polymers, for example, polystyrene, styrene-modified polyesters, ABS (acrylonitrile-butadiene-styrene), and SAN (styrene-acrylonitrile) plastics. The global production of styrene in 2018 amounted to ~ 30 million tons, with up to 90% of styrene obtained by dehydrogenation of ethylbenzene in the presence of water vapor.

Design and Numerical Simulation of Piezoelectrically-Driven Single Piston Pump With Distributing Valves

In this paper, a piezoelectrically driven single piston pump is designed for high delivery pressure and large displacement. It is composed of a piezoelectric stack, a hydrostatic amplifier and a plunger with two check valves from a radial plunger pump commercially available. Passive check valves instead of active membranes in the pump allow higher pressure delivery, and the hydrostatic amplifier is adopted for larger displacement of the pump. In order to study delivery characteristic of a piezoelectrically driven single piston pump, numerical simulation of unsteady flow inside the pump is conducted by computational fluid dynamics (CFD). Moving mesh technique is adopted to characterize the behavior of two check valves for oil distributing. Influences of typical design and operation parameters on delivery performance of the single piston piezo pump are analyzed. The results show that, driving frequency and spring stiffness of the valves and chamber configuration should be properly designed for stable oil delivery with low flow ripple as possible. Numerical simulation is valid to describe the behavior of the pump, on target for theoretical reference to its counterparts used in miniature EHA actuators.