Application Of Nets Research Articles

Application of Petri nets to performance evaluation of subsea blowout preventer system

This paper presents an application of deterministic and stochastic Petri nets (DSPN) to evaluate the performance of subsea blowout preventer (BOP) system. The overall subsea BOP system is comprised of five mechanical subsystems and five electrical subsystems, which can be viewed as a series-parallel system. In regard to common cause failures, TimeNET 4.0 toolkit is utilized to develop and analyze the DSPN models. Availability and reliability of the subsea BOP system and its subsystems are obtained. Besides, the effects of failure rate and repair time of each component on system performance are researched.

Petri nets in systems biology

Petri nets are used in many areas. This article discusses the application of Petri nets in systems biology. Using an example from biochemistry, concepts for the automatic decomposition of biochemical systems are introduced. The article focuses on those concepts that fulfill steady-state conditions. Interestingly, all the concepts are based on minimal, semi-positive transition invariants. The article describes, which new definitions for network decomposition can be derived and how they can be interpreted in the context of biology. This is illustrated with the example of the citric acid cycle, for which a new metabolic pathway could be predicted with the help of such an analysis.

Quantifying fish species richness and abundance in Amazonian streams: assessment of a multiple gear method suitable for Terra firme stream fish assemblages

AbstractA multigear sampling method to quantify fish richness and abundance in Amazonian Terra firme streams was assessed. This method is based on the four‐pass removal method using the combined application of different nets. The efficiency of the method was explored over 10 replicated sites along three streams over day, night and seasons. Use of four successive passes allowed both abundant and rare species to be collected and the abundance of common species to be estimated. On average, a high proportion (41%) of rare species was collected per sample (only one or two individuals) after four fishing passes. The efficiency of the sampling method to detect species richness per sample between successive passes was estimated using an autosimilarity approach. Although species richness and abundance increased with successive passes, no major differences were obtained between the third and fourth pass. A single pass considerably underestimated the richness and abundance of species in these type of streams, and night sampling also increased beta‐diversity by at least 20%. Abundance estimates demonstrated high efficiency with an overall sampling error of only 8 and 11% for samples and single species, respectively. Capture efficiency differed among fish species exhibiting different ecological traits and showed significant differences among seasons for total samples. Results supported the robustness of the method and its suitability to quantify fish richness and abundance in small, wadeable Amazonian Terra firme streams inhabited by highly diverse fish assemblages.

Analysis and Application of Logical Petri Nets to E-Commerce Systems

Logical Petri Nets (LPNs) can well describe and analyze batch processing functions and passing value indeterminacy in cooperative systems. Their structures are simpler than the equivalent inhibition Petri nets. To analyze them, a vector matching method has been given. In this paper a subclass of LPNs is proposed and its properties are analyzed. It can be used to model and simulate e-commerce systems well. Its special structures and relationships among its logical transitions are discussed. Based on them, a reachability tree is constructed and the state equations are used to analyze its properties, that is, reachability, liveness, conservativeness, and reversibility. The proposed analysis method significantly lowers the computational efforts in comparison with the existing method for LPNs.

P-Time PN and Control of Time Constrained Systems

The main scope of this contribution is to discuss and to analyse the application of time Petri nets for modelling and control of time-critical systems. The time-critical aspect is with respect to the dependence of system behaviour to the actions that are performed, but also on their performing time instants and their performing durations, chosen within an interval. This is the case of electroplating process where chemical treatment operations must be performed based on a reliable respect of several time constraints on chemical tank treatment times and on hoist transfer time.

A personalized Wireless Sensor Network Communication Model for computerization of Electric Power Distribution

Automation of electric power distribution in a l o a d p o i n t b y p r o v i d i n g reliable manner and cost-efficient can be accomplished by complete automation of the central control centre which coordinates the operation of several area centers while ensuring security of supply against loss of generation, transmission capacity, maintaining the voltage, current and frequency of the system within specified limits, temperature, pressure, and oil level of the transformers is required. Currently, automation is done with the help of Supervisory Control and Data Acquisition (SCADA) and Intelligent Electronic Devices (IEDs). A novel method is proposed in this paper about communication among the sensors. In this paper the cooperative wireless sensor network architecture for communication of the monitored signals and the employment of a virtual MIMO model, which would considerably reduce errors due to transient surge of charges and other interferences were discussed. Further, the paper proposes the use of a location aware protocol, GEAR, which is suitable for the sensor network architecture, as compared to the currently used protocols. The appropriate placement of sensors and adoption of additional signaling schemes can also prevent theft of electrical power, which is not a new problem in many areas. The application of sensor networks is becoming ever-present, and this paper introduces a new area of application of the sensor nets viz. in the automation of electrical power distribution. The automation of power distribution can be made well-organized in terms of energy utilization, speed, and bandwidth necessities from beginning to end to the application of sensor nets. The efficient elements that achieve security control and monitoring of the various signals are the sensor networks. The essential fault analysis system should provide results of a complete system-wide analysis of an event to the system dispatchers and safety engineers within seconds of the event happening. This may not be feasible with the existing SCADA technology. Wei Ye et al. (4) mention that the major drawback of current SCADA systems is that they are static, inflexible, and often have a centralized architecture. Further, there may be increased operational risks (8) associated with an inconsistent level of staff operational competency. In that case, the human intervention in decision making has to be minimized. In the proposed communication model, the processing of data signals by a single control centre (master) processor is decentralized, and the processing of information may be done in a distributed manner. Each sensor node may have a battery for its operation. The nodes are asleep, and unless there is a significant change in the measured parameters, only then they transmit. This avoids redundant transmission and hence saves a considerable amount of power and complex wiring to link all these sensors to the control equipment is eliminated through low power wireless transmission. The bandwidth requirement is least since the transmissions are mostly limited and are done only when necessary. The process of communication among the sensors is divided into the following phases: The long-haul transmission of signals to the monitoring (HMI) stations by strategic placement of the sensor clusters and implementing the location- based GEAR protocol and the communication of signals within clusters of the sensors that are in close proximity to each other on a virtual MIMO basis. The paper proposes the use of a location-based routing protocol called GEAR (Geographic and Energy Aware Routing) that implements energy efficient geographic packet forwarding techniques. The GEAR protocol is energy efficient on its own, and it would make possible faster communication. The location of sensors can be obtained by means of a hardware system (GPS) or by irregular beaconing. Since in the electric distribution network the sensors are rather static, the location information need not be transmitted frequently. This reduces the overhead in routing, as compared to other sensor networks scenarios. The broadcasting of information sensed by the sensors or a question that is sent by the base station is a primary need in the automation of power distribution. The broadcasting of data is done in a faster manner by use of the GEAR protocol. The assumption made (2) is that the energy consumed for processing is far

Novel Vectors of Malaria Parasite in the Western Highlands of Kenya

To the Editor: The primary malaria control techniques, indoor application of residual insecticides and insecticide-treated bed nets, are used on the basis of previously assumed key characteristics of behaviors of vectors of malaria parasites, i.e., resting and feeding indoors (1). Any deviation from the typical activities of a species related to exophagy (feeding outdoors) and exophily (living and resting indoors) (2) or to population replacement, followed by increased outdoor biting or resting (3), may undermine malaria control efforts. Identification of mosquitoes that transmit malaria parasites has, for the most part, relied on the use of outdated morphologic keys (4,5) and, more recently, species-diagnostic PCR (6). Cryptic species or subpopulations that exhibit divergent behaviors (7) may be responsible for maintaining malaria parasite transmission, and without adequate discriminatory techniques, these vectors may be misidentified and their key behavioral differences overlooked.

Mapping the surface movement area operations: An application of Petri Nets to the case of New York JFK airport

In response to the need for managing demand and capacity in the Air Transportation System (ATS), a wide range of improvements are envisioned in the next generation ATS (NextGen). These improvements include the use of new operational procedures as well as new technologies and infrastructure. The impact of NextGen improvements on the efficiency of the ATS and on user and service provider business objectives is of interest to multiple stakeholders. In particular, ramp and taxiway congestion, and taxiway and runway construction projects at airports have made it necessary for analysts to understand surface operations with greater precision. In this paper, the authors introduce aviation practitioners to the concept of Petri Nets for performance analysis of airport surface operations. Together with high fidelity flight surface movement data from the ASDE-X system installed at New York John F. Kennedy International airport (one of a number of airports with this capability), they show how Petri Nets may be used to derive measures of congestion, runway throughput and utilisation, to present stakeholders with the necessary information to make informed planning decisions.

Application of Petri nets for systems modelling and analysis

Petri nets are powerful graphical and mathematical modelling tool for describing and studying various types of system. Petri nets can be used not only to express the static behaviours of logic operation such as logical relations between system components, but also to study the dynamic behaviours such as operating sequence, workflow, maintenance process, failure occurrence and concurrent activities of the system Petri net model has been developed for LHD motor-overheating problem. Petri nets have been used to identify minimum cut sets finding, marking transfer, firing sequence, reachability tree and dynamic behaviour of machine failure. A model is formulated for fault detection and isolation.

Application of high-level fuzzy Petri nets to educational grading system

For the purpose of understanding the students’ learning achievement, the most direct way is to implement a test. Due to the rapid development of information technology, all kinds of combination of information technology with the adaptive test have been incessantly noted by many scholars. In general, the computerized adaptive test includes the item response theory that tests the students’ learning ability of subjects. However, the results based only on the dichotomy of correct answers and wrong answers are not so comprehensive judgments. Situations of correct answers and wrong answers should be different in their degrees; for example, completely correct, partially correct, completely wrong, and partially wrong. But the partially correct or partially wrong is vague and difficult to define. Thus it is appropriate to use fuzzy theory to solve the vagueness problem. Therefore, this study presents a novel learning evaluation model which applies high-level fuzzy Petri net (HLFPN) and infers via a fuzzy reasoning method the different answering performances generated by different examinee’s abilities corresponding to the test items in different degrees of difficulty. Finally, we synthesize the answering performance of every test item and make a reasonable evaluation.

APLIKASI PETRI NET PADA SISTEM PEMBAYARAN TAGIHAN LISTRIK PT. PLN (Persero) RAYON AMBON TIMUR

Petri Net is a model of Mathematics used in the system event discrit to illustrate certain event. One application of Petri Nets is to sketch the entrance occurs in a place like the public service system. This reserce will simply describe the use of Petri Net to sketch the entrance occurs in electricity bill payment system of PT.PLN (Persero) Rayon Ambon Timur by the number of place is 7 and the transition is 8, and to determine the matrix representation and the coverability tree of the model.

Extended Contract Nets Application in Wood Drying Kiln

The article aims at the problems such as the traditional contract nets model’s communication traffic is too heavy in the consultation process; task’s partition is fixed; evaluation index is not comprehensive, proposes a contract nets improvement method based on the bidding threshold and evaluation function by combining the response threshold model of the ant colony algorithm. This method introduce fuzzy synthetic computation, finding the potential cooperation relations between node agents, bottom-up decomposing the complex task, effectively reduce the negotiation time and communication flows, improve the efficiency of the system. The thesis combines wood drying application feature, and puts forward the improved model’s experimental simulation in wood drying kiln. The result shows that the improved method can effectively improve the performance of the Contract Net Protocol in large-scale multi-agent system. It provides technical basis for the realization of wood drying cluster control.

Application of the Bayesian Belief Nets in dam safety monitoring

Application of the Bayesian Belief Nets in dam safety monitoring The systems for earth dam monitoring should enable measurements of basic physical parameters describing the behavior of the structure, including: soil water pressure, soil stress, displacements, leaks, and drainage discharges. In the case of earth dam safety assessment, the monitoring data are used to detect any anomalies in dam behavior. In this paper, the dam safety has been analyzed using the Bayesian Nets. Two types of information: water pressure measurements and drainage discharge measurements are used in analyses. The seepage anomalies in the Klimkówka Dam were considered in demonstrate the practical advantages of using the Bayesian Nets for monitoring data interpretation. Presented examples of the Bayesian Nets applications (forward and backward propagation) in analysis of seepage through earth dams show that this method can be an effective tool supporting an assessment of dams technical condition and monitoring of the dam safety.

Using Influence Nets in Financial Informatics: A Case Study of Pakistan

The paper presents an application of Influence Nets (INs) in the field of financial informatics. Influence Nets have primarily been used in war games to model effects based operations but, as shown in this paper, they can prove to be equally useful in other domains requiring decision making under uncertain situations. The primary advantage of INs lies in their ability to acquire knowledge from subject matter experts in problem domains that rely heavily on experts’ opinion. A sample case study from the fields of economics and finance is presented in this paper. The case study models the choices faced by a developing country to recover her economy which is going through a difficult phase due to global financial crisis, internal law and order situation and political instability.

Internetware Structure Description and Research of the Petri Net Method

Architecture design and specification is more important than algorithm or data structure establishment for a complex system, existing Architecture Description Languages are difficult to support the complete Internetware developing process. Petri nets describe system graphically and mathematically, provide a way to solve the problems in Internetware description and development. In this paper we investigate Internetware architecture description methods, current application of Petri nets in Internetware and the deficiency; present basic principles to describe Internetware architecture using Petri nets, the possible architecture model and architecture evolution mechanisms; discuss subnet based Web services composition description technologies; present the idea of developing Internetware using Petri nets as a whole process unified model. The Petri net method helps to transfer among different stages of Internetware developing easily; the smooth transition from architecture description to code implementation makes sure a good design can deduce a good realization.

The rod and the crocodile. Temporal relations in textual hermeneutics: An application of Petri nets to semantics

We use a graphic formalism to make explicit differences in the interpretation of temporal relations in natural-language text. Out of the panoply of computational representation methods for time or tense, we select Petri nets, and discuss why. We illustrate their potential for semantics and for sign theorists, by analyzing how some late antique and medieval exegeses understood the narrative of Moses and Pharaoh's magicians, and the former's rod swallowing up the rods of the other ones, once these rods had been turned into crocodiles or snakes. We extend the treatment to another situation concerning the semantics of eating and being eaten.

Assigning Ontological Meaning to Workflow Nets

A common way to represent organizational domains is the use of business process models. A Workflow-net (WF-net) is an application of Petri Nets (with additional rules) that model business process behavior. However, the use of WF-nets to model business processes has some shortcomings. In particular, no rules exist beyond the general constraints of WF-nets to guide the mapping of an actual process into a net. Syntactically correct WF-nets may provide meaningful models of how organizations conduct their business processes. Moreover, the processes represented by these nets may not be feasible to execute or reach their business goals when executed. In this paper, the authors propose a set of rules for mapping the domain in which a process operates into a WF-net, which they derived by attaching ontological semantics to WF-nets. The rules guide the construction of WF-nets, which are meaningful in that their nodes and transitions are directly related to the modeled (business) domains. Furthermore, the proposed semantics imposes on the process models constraints that guide the development of valid process models, namely, models that assure that the process can accomplish its goal when executed.

Control of pyrethroid and DDT-resistant Anopheles gambiae by application of indoor residual spraying or mosquito nets treated with a long-lasting organophosphate insecticide, chlorpyrifos-methyl

BackgroundScaling up of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) with support from the Global Fund and President's Malaria Initiative is providing increased opportunities for malaria control in Africa. The most cost-effective and longest-lasting residual insecticide DDT is also the most environmentally persistent. Alternative residual insecticides exist, but are too short-lived or too expensive to sustain. Dow Agrosciences have developed a microencapsulated formulation (CS) of the organophosphate chlorpyrifos methyl as a cost-effective, long-lasting alternative to DDT.MethodsChlorpyrifos methyl CS was tested as an IRS or ITN treatment in experimental huts in an area of Benin where Anopheles gambiae and Culex quinquefasiactus are resistant to pyrethroids, but susceptible to organophosphates. Efficacy and residual activity was compared to that of DDT and the pyrethroid lambdacyalothrin.ResultsIRS with chlorpyrifos methyl killed 95% of An. gambiae that entered the hut as compared to 31% with lambdacyhalothrin and 50% with DDT. Control of Cx. quinquefasciatus showed a similar trend; although the level of mortality with chlorpyrifos methyl was lower (66%) it was still much higher than for DDT (14%) or pyrethroid (15%) treatments. Nets impregnated with lambdacyhalothrin were compromized by resistance, killing only 30% of An. gambiae and 8% of Cx. quinquefasciatus. Nets impregnated with chlorpyrifos methyl killed more (45% of An gambiae and 15% of Cx. quinquefasciatus), but its activity on netting was of short duration. Contact bioassays on the sprayed cement-sand walls over the nine months of monitoring showed no loss of activity of chlorpyrifos methyl, whereas lambdacyhalothrin and DDT lost activity within a few months of spraying.ConclusionAs an IRS treatment against pyrethroid resistant mosquitoes chlorpyrifos methyl CS outperformed DDT and lambdacyhalothrin. In IRS campaigns, chlorpyrifos methyl CS should show higher, more-sustained levels of malaria transmission control than conventional formulations of DDT or pyrethroids. The remarkable residual activity indicates that cost-effective alternatives to DDT are feasible through modern formulation technology.

Application of Petri nets to reliability prediction of occupant safety systems with partial detection and repair

This paper presents an application of stochastic Petri nets (SPN) to calculate the availability of safety critical on-demand systems. Traditional methods of estimating system reliability include standards—based or field return-based reliability prediction methods. These methods do not take into account the effect of fault-detection capability and penalize the addition of detection circuitry due to the higher parts count. Therefore, calculating system availability, which can be linked to the system's probability of failure on demand ( P fd), can be a better alternative to reliability prediction. The process of estimating the P fd of a safety system can be further complicated by the presence of system imperfections such as partial-fault detection by users and untimely or uncompleted repairs. Additionally, most system failures cannot be represented by Poisson process Markov chain methods, which are commonly utilized for the purposes of estimating P fd, as these methods are not well-suited for the analysis of non-Poisson failures. This paper suggests a methodology and presents a case study of SPN modeling adequately handling most of the above problems. The model will be illustrated with a case study of an automotive electronics airbag controller as an example of a safety critical on-demand system.

Application of Petri nets for the energy management of a photovoltaic based power station including storage units

This paper deals with the energy management of a photovoltaic based power station. This power station includes storage units with batteries for long-term energy supply and ultracapacitors for fast dynamic power regulation. According to the availability of the primary source, the level of the stored energy and the request from the grid operator, we have defined and detailed three main operating modes for this system with a particular modeling tool: Petri nets. For each operating mode, we have designed an energy management algorithm in order to calculate the energy dispatching of an adjustable power margin for the storage units.