General Nets Research Articles

Modeling the Production Process of Fuel Gas, LPG, Propylene, and Polypropylene in a Petroleum Refinery Using Generalized Nets

The parallel processes involved in the production of refinery fuel gas, liquid petroleum gas (LPG), propylene, and polypropylene, occurring in thirteen refinery units, are modeled by the use of a Generalized Net (GN) apparatus. The modeling of the production of these products is important because they affect the energy balance of petroleum refinery and the associated emissions of greenhouse gases. For the first time, such a model is proposed and it is a continuation of the investigations of refinery process modelling by GNs. The model contains 17 transitions, 55 places, and 47 types of tokens, and considers the orders of fuel gas for the refinery power station, refinery process furnaces, LPG, liquid propylene, and 6 grades of polypropylene. This model is intended to be used as a more detailed lower-level GN model in a higher-level GN model that facilitates and optimizes the process of decision making in the petroleum refining industry.

Generalized Net Model of Coyote Optimization Algorithm

In the presented paper, the functioning of the coyote optimization algorithm (COA) is described using the apparatus of generalized nets (GNs). The COA is a population-based metaheuristic for optimization inspired by the Canis latrans species. Based on a Universal GN-model of population-based metaheuristics, а GN-model of COA is constructed by setting different characteristic functions of the GN-tokens. The presented GN-model successfully describes the considered metaheuristic algorithm, conducting basic steps and performing an optimal search.

A Generalized Net Model of the Prostate Gland’s Functioning

Over the last 20 years, many Generalized Net (GN) models of the ways of functioning of the different systems and organs in the human body and models related to the description of biomedical processes in living organisms have been constructed. In this paper, a GN model of the prostate gland’s functioning was developed, as a continuation of the previous research. The model provides the possibility to trace the logical relations of the interactions of the prostate gland and various individual organs in the human body. The model shows the possibility for the existence of currently unknown feedback loops.

Generalized Net Model for Telecommunication Processes in Telecare Services

In a series of papers, Generalized Net (GN) models of processes, related to tracking changes in the health status of adult patients, have been presented. The contemporary state-ofthe- art of the telecommunications and navigation technologies allow these models to be further extended to the case of active and mobile patients. This requires the inclusion of patient’s current location as a new and significant variable of the model. Various opportunities are considered for the retrieval of this information, with a specific focus on the optimal ones, and a refined GN model is herewith proposed.

Generalized Net Model of Forest Zone Monitoring by UAVs

The paper presents a generalized net (GN) model of the process of terrain observation with the help of unmanned aerial vehicles (UAVs) for the prevention and rapid detection of wildfires. Using a GN, the process of monitoring a zone (through a UAV, which is further called a reconnaissance drone) and the localization of forest fires is described. For a more indepth study of the terrain, the reconnaissance drone needs to coordinate with a second UAV, called a specialized drone, so that video and sensory information is provided to the supervising fire command operational center. The proposed GN model was developed to assist in the decision-making process related to the coordination of the operation of both UAVs under dynamically changing terrain circumstances, such as those related to preventing or quickly containing wildfires. It describes the stages (transitions), logical determinants (transition predicate matrices), and directions of information flow (token characteristics) within the process of localization of fires using the pair of reconnaissance and specialized drones.

Modelling the Process of Production of Diesel Fuels by the Use of Generalized Nets

The process of commodity diesel fuel production in a refinery has been modelled by the use of the Generalized Net (GN) apparatus. GNs are extensions of Petri nets and of all their modifications and extensions. The model accounts for the orders of different grades of diesel fuel and the available amounts of the different diesel fuel components. It can be used for the synchronization and optimization of these processes.

Cuckoo search and firefly algorithms in terms of generalized net theory

In the presented paper, the functioning and the results of the work of two metaheuristic algorithms, namely cuckoo search algorithm (CS) and firefly algorithm (FA), are described using the apparatus of generalized nets (GNs), which is an appropriate and efficient tool for describing the essence of various optimization methods. The two developed GN-models mimic the optimization processes based on the nature of cuckoos and fireflies, respectively. The proposed GN-models execute the two considered metaheuristic algorithms conducting basic steps and performing optimal search. Building upon these two GN-models, a universal GN-model is constructed that can be used for describing and simulating both the CS and the FA by setting different characteristic functions of the GN-tokens. Moreover, the universal GN-model itself can be transformed to each of the herewith presented GN-models by applying appropriate hierarchical operators. In order to validate the proposed universal GN-model, numerical experiments are performed for the operating of the universal GN-model (CS and FA) on benchmark mathematical functions. The obtained results are compared with the results of the GN-model of CS, GN-model of FA, as well as the results of the standard CS and FA.

Generalized Net Model of Auditory Information Processing

In a series of papers we have described the human body, its separate systems, and their behavior using Generalized Nets (GNs). Here we construct a GN-model that represents auditory information processing - the first on our research on the structure and behavior of the human nervous system.

Fast computation of a gated dipole field

We address the need to develop efficient algorithms for numerical simulation of models, based in part or entirely on adaptive resonance theory. We introduce modifications that speed up the computation of the gated dipole field (GDF) in the Exact ART neural network. The speed increase of our solution amounts to at least an order of magnitude for fields with more than 100 gated dipoles. We adopt a 'divide and rule' approach towards the original GDF differential equations by grouping them into three categories, and modify each category in a separate way. We decouple the slow-dynamics part - the neurotransmitters from the rest of system, solve their equations analytically, and adapt the solution to the remaining fast-dynamics processes. Part of the node activations are integrated by an unsophisticated numerical procedure switched on and off according to rules. The remaining activations are calculated at equilibrium. We implement this logic in a Generalized Net (GN) - a tool for parallel processes simulation which enables a fresh look at developing efficient models. Our software implementation of generalized nets appears to add little computational overhead.

Generalized Nets Modelling of a Chromatically Controlled, Industrial Plasma Process

Structure and functioning of a plasma technology based, industrial production system - plasma spray facility - are modelled by Generalized Nets (GN) which are a modification of the Petri-nets. Two feedback loops serve to pre-set the system and to perform on-line corrective actions. The latter uses chromatic monitoring of the plasma jet. After a brief introduction to the concept of GN, we present graphical structure of our model as well as physical meaning and formal description of its elements. An illustrative simulation example for monitoring and corrective actions is presented.

Decentralized system for production planning and control of soft drink production using generalized nets

A Production Planning and Control (PPC) system for soft drink production is developed as a distributed system to cope with the uncertain economic environment, diversified customers needs and plant disturbances. The paper describes a novel approach for design a small intelligent PPC system based on holonic concepts and using the methodology of Generalized Nets (GNs). The proposed approach is very suitable for planning and control of hybrid production systems and is applied using the software tool “GNET” with DDE connection to the MS - Office.

Generalized nets in neurology: an example of mathematical modelling

The purpose of this paper is to explain the basic theory of generalized nets (GNs) and their applications in the context of the differential diagnosis of neurological diseases. We define formally the concepts of a GN and transitions of a GN and also outline some remarks on their theory. The work here constructs an example which aims to trace the process of diagnosing different signs and symptoms in neurology. This will enable the interested reader to see the scope of nets in general as tools for the modelling, simulation, optimization and control of real processes.

Formal communication in science: A model based on generalized nets

A schematic overview of the formal communication process is first presented. Emphasis is placed only on the specific functions and participants required to transfer article manuscripts from the author to the reader of scientific journals. For the description of this process a mathematical model based on generalized nets (GN) is then proposed. Some advantages of the GN as compared to other models are shown. Model application is not included since the programme package which realizes the GN is in a stage of preparation.