Graphical Modeling Tool Research Articles

Modeling and Control of a Novel Linear-Driven Electro-Hydrostatic Actuator Using Energetic Macroscopic Representation

Energetic macroscopic representation (EMR) is an effective graphical modeling tool for multiphysical systems, and EMR model clearly illustrates the power flow and interaction between different subcomponents. This paper presents the modeling and control of a novel linear-driven electro-hydrostatic actuator (LEHA) with EMR method. The LEHA is a novel electro-hydrostatic actuation system, and the hydraulic cylinder in LEHA is driven by a novel collaborative rectification pump (CRP), which incorporates two miniature cylinders and two spool valves. EMR model clearly illustrated the powertrain in LEHA and interaction between each components. Based on EMR model, a maximum control structure (MCS) is easily deduced using the action and reaction principle, and then the practicable controller deduced from MCS shows satisfying performance in the simulation.

Modeling, analysis and verification of real-time resource access control protocols: a formal approach

An important characteristic of real-time systems is to produce the expected results within the predefined time period. Efficient scheduling of multiple tasks and utilization of shared resources among these tasks for hard real-time systems is an important area of research. Due to the growing complexities and requirements of the present time, it is not easy to model such systems. Unified Modeling Language (UML) is a graphical modeling tool which is a very popular industry-standard visual language used for system design. However, due to the semi-formal representation, UML has its own shortcomings and cannot be called a complete modeling language for real-time systems. It lacks simulation and verification capabilities. Considering those drawbacks this research work formally analyzes two real-time resource access control protocols using CFG/BNF notation. Further, the formal notations are confirmed by ANother Tool for Language Recognition.

CINCO: a simplicity-driven approach to full generation of domain-specific graphical modeling tools

Even with the help of powerful metamodeling frameworks, the development of domain-specific graphical modeling tools is usually a complex, repetitive, and tedious task, which introduces substantial upfront costs often prohibiting such approaches in practice. In order to reduce these costs, the presented Cinco meta tooling suite is designed to provide a holistic approach that greatly simplifies the development of such domain-specific tools. Our solution is based on the idea to apply the concept of domain specialization also to the (meta-)domain of “domain-specific modeling tools”. Important here is our focus on complex graph-based models, comprising various kinds of nodes and edges together with their individual representation, correlations, and interpretation. This focus allows for high-level specifications of the model structures and functionalities as the prerequisite for push-button tool generation.

A methodological approach for using high-level Petri Nets to model the immune system response.

BackgroundMathematical and computational models showed to be a very important support tool for the comprehension of the immune system response against pathogens. Models and simulations allowed to study the immune system behavior, to test biological hypotheses about diseases and infection dynamics, and to improve and optimize novel and existing drugs and vaccines.Continuous models, mainly based on differential equations, usually allow to qualitatively study the system but lack in description; conversely discrete models, such as agent based models and cellular automata, permit to describe in detail entities properties at the cost of losing most qualitative analyses. Petri Nets (PN) are a graphical modeling tool developed to model concurrency and synchronization in distributed systems. Their use has become increasingly marked also thanks to the introduction in the years of many features and extensions which lead to the born of “high level” PN.ResultsWe propose a novel methodological approach that is based on high level PN, and in particular on Colored Petri Nets (CPN), that can be used to model the immune system response at the cellular scale. To demonstrate the potentiality of the approach we provide a simple model of the humoral immune system response that is able of reproducing some of the most complex well-known features of the adaptive response like memory and specificity features.ConclusionsThe methodology we present has advantages of both the two classical approaches based on continuous and discrete models, since it allows to gain good level of granularity in the description of cells behavior without losing the possibility of having a qualitative analysis. Furthermore, the presented methodology based on CPN allows the adoption of the same graphical modeling technique well known to life scientists that use PN for the modeling of signaling pathways. Finally, such an approach may open the floodgates to the realization of multi scale models that integrate both signaling pathways (intra cellular) models and cellular (population) models built upon the same technique and software.

Reusing metamodels and notation with Diagram Definition

It is increasingly common for language specifications to describe visual forms (concrete syntax) separately from underlying concepts (abstract syntax). This is typically to enable interchange of visual information between graphical modeling tools, such as positions of nodes and routings of lines. Often overlooked is that separation of visual forms and abstract concepts enables languages to define multiple visual forms for the same underlying concepts and for the same visual form to be used for similar underlying concepts in different languages (many-to-many relationships between concrete and abstract syntax). Visual forms can be adapted to communities using different notations for the same concepts and can be used to integrate communities using the same notation for similar concepts. Models of concrete syntax have been available for some time, but are rarely used to capture these many-to-many relationships with abstract syntax. This paper shows how to model these relationships using concrete graphical syntax expressed in the Diagram Definition standard, examining cases drawn from the Unified Modeling Language and the Business Process Model and Notation. This gives definers of graphical languages a way to specify visual forms for multiple communities.

Methodology for technical and economic assessment of electric vehicles integration in distribution grid

This paper proposes a methodology to design a supervision system (SS) based on Fuzzy and Boolean logics. In the first stage, a graphical modeling tool is used to facilitate the analysis and the determination of Fuzzy–Boolean algorithm linked to the test system. To improve the performance of the proposed SS a genetic algorithm (GA) is implemented in the second stage. The SS objective is used to control electric vehicles (EVs) load in order to minimize the energy transmission costs (ETC) of the distribution system operator (DSO). To achieve this goal, it is necessary to promote local consumption of wind and photovoltaic (PV) power by coordinating them with EVs load, maximize EVs charging during cheaper energy periods and reduce subscribed power exceeding. The performance of the SS is shown by numerical simulation results using Matlab/Simulink. Finally, a Matlab–PowerFactory co-simulation framework is proposed in order to assess supervision system influence on the technical aspects of a real test grid.

Pragmatic model transformations for refactoring in Scilab/Xcos

Model-Based Development has become an industry wide standard paradigm. As an open source alternative, Scilab/Xcos is being widely employed as a hybrid dynamic systems modeling tool. With the increasing efficiency in implementation using graphical model development and code generation, the modeling and simulation community is struggling with assuring quality as well as maintainability and extendibility. Refactoring is defined as an evolutionary modernization activity where, most of the time, the structure of the artifact is changed to alter its quality characteristics, while keeping its behavior unchanged. It has been widely established as a technique for textual programming languages to improve the code structure and quality. While refactoring is also regarded as one of the key practices of model engineering, the methodologies and approaches for model refactoring are still under development. Architecture-Driven Modernization (ADM) has been introduced by the software engineering community as a model-based approach to software modernization, in which the implicit information that lies in software artifacts is extracted to models and model transformations are applied for modernization tasks. Regarding refactoring as a low level modernization task, the practices from ADM are adaptable. Accordingly, this paper proposes a model-based approach for model refactoring in order to come up with more efficient and effective model refactoring methodology that is accessible and extendable by modelers. Like other graphical modeling tools, Scilab/Xcos also possesses a formalized model specification conforming to its implicit metamodel. Rather than proposing another metamodel for knowledge extraction, this pragmatic approach proposes to conduct in place model-to-model transformations for refactoring employing the Scilab/Xcos model specification. To construct a structured model-based approach, the implicit Scilab/Xcos metamodel is explicitly presented utilizing ECORE as a meta-metamodel. Then a practical model transformation approach is established based on Scilab scripting. A Scilab toolset is provided to the modeler for in-place model-to-model transformations. Using a sample case study, it is demonstrated that proposed model transformation functions in Scilab provide a valuable refactoring tool.

DSML4CP: A Domain-specific Modeling Language for Concurrent Programming

Nowadays, concurrent programs are an inevitable part of many software applications. They can increase the computation performance of the applications by parallelizing their computations. One of the approaches to realize the concurrency is using multi thread programming. However, these systems are structurally complex considering the control of the parallelism (such as thread synchronization and resource control) and also considering the interaction between their components. So, the design of these systems can be difficult and their implementation can be error-prone especially when the addressed system is big and complex. On the other hand, a Domain-specific Modeling Language (DSML) is one of the Model Driven Development (MDD) approaches which tackles this problem. Since DSMLs provide a higher abstraction level, they can lead to reduce the complexities of the concurrent programs. With increasing the abstraction level and generating the artifacts automatically, the performance of developing the software (both in design and implementation phases) is increased, and the efficiency is raised by reducing the probability of occurring errors. Thus, in this paper, a DSML is proposed for concurrent programs, called DSML4CP, to work in a higher level of abstraction than code level. To this end, the concepts of concurrent programs and their relationships are presented in a metamodel. The proposed metamodel provides a context for defining abstract syntax, and concrete syntax of the DSML4CP. This new language is supported by a graphical modeling tool which can visualize different instance models for domain problems. In order to clarify the expressions of the language; the static semantic controls are realized in the form of constraints. Finally, the architectural code generation is fulfilled via model transformation rules using the templates of the concurrent programs. To increase level of the DSML׳s leverage and to demonstrate the general support of concurrent programming by the DSML, the transformation mechanism of the tool supports two well-known and highly used programming languages for code generation; Java and C#. The performed experiments on two case studies indicate a high performance for proposed language. In this regard, the results show automatic generation of 79% of the final code and 86% of the functions/modules on average.

The Relation between the Stabilization Problem for Discrete Event Systems Modeled with Timed Petri Nets via Lyapunov Methods and Max-Plus Algebra

A discrete event system is a dynamical system whose state evolves in time by the occurrence of events at possibly irregular time intervals. Timed Petri nets are a graphical and mathematical modeling tool applicable to discrete event systems in order to represent its states evolution where the timing at which the state changes is taken into consideration. One of the most important performance issues to be considered in a discrete event system is its stability. Lyapunov theory provides the required tools needed to aboard the stability and stabilization problems for discrete event systems modeled with timed Petri nets whose mathematical model is given in terms of difference equations. By proving stability one guarantees a bound on the discrete event systems state dynamics. When the system is unstable, a sufficient condition to stabilize the system is given. It is shown that it is possible to restrict the discrete event systems state space in such a way that boundedness is achieved. However, the restriction is not numerically precisely known. This inconvenience is overcome by considering a specific recurrence equation, in the max-plus algebra, which is assigned to the timed Petri net graphical model.

A Metamodel and Graphical Syntax for NS-2 Programing

One of the most important issues, around the world, which manufacturers pay special attention to is to promote their activities in order to be able to give high quality products or services. Perhaps the first advice to achieve this goal is simulation idea. Therefore, simulation software packages with different properties have been made available. One of the most applicable simulators is NS-2 which suffers from internal complexity. On the other hand, Domain Specific Modeling Languages can make an abstraction level by which we can overcome the complexity of NS-2, increase the production speed, and promote efficiency. So, in this paper, we introduce a Domain Specific Metamodel for NS-2.This new metamodel paves the ways for introducing abstract syntax and modeling language syntax. In addition, created syntax in Domain Specific Modeling Language is supported by a graphical modeling tool.

A Comprehensive Survey of Flexible Manufacturing System Scheduling Using Petri Nets

A Flexible Manufacturing System (FMS) is an integrated, computer-controlled system of machines, automated handling systems, and storage systems that can be used to simultaneously manufacture a variety of jobs. FMSs can be characterized as asynchronous, concurrent, distributed and parallel systems in which multiple operations share multiple resources so that the performance criteria are optimized. Petri nets (PNs) have recently become a promising approach for modeling FMSs. PNs are formal graphical modeling tool that can be efficiently utilized as a process analysis and modeling tool, because it shows graphically and dynamically to simulate a process in an integrated manner. It is a mathematical modeling technique that is useful for modeling concurrent, asynchronous, distributed, parallel, nondeterministic, and stochastic systems. Unreasonably the dispatching resources/jobs to machine in FMS may result in a deadlock situation and the situation is studied thoroughly and avoided through PN techniques. From the design and analysis point of view, the uses of nets have many advantages in modeling, performance evaluation, qualitative analysis and code generation. Scheduling a manufacturing system is usually a Non-Polynomial hard problem. This means that only heuristic algorithms can be used to provide near-optimal schedule when it is merged with PN. The merging of PNs with knowledge based heuristic techniques seems to be very promising to deal with large complex discrete event dynamic systems. This paper presents a comprehensive survey of FMS that combines PNs with other methods.

Towards the integration of the agent-oriented modeling diversity with a powertype-based language

Multi-agent Systems (MASs) are one of the main fields of distributed systems. MASs are based on autonomous entities that cooperate obtaining emergent behaviors, and can be useful for integrating open systems. However, the great diversity of agent-oriented modeling languages (AOMLs) hinders the understanding and interchange of MAS models. Most MAS concepts are shared among the AOMLs. However, these concepts have certain peculiarities in each AOML, such as the expected behavior and concrete syntax. This paper presents a metamodeling solution for the integration of the AOML diversity that uses the powertype pattern. In this pattern, the clabjects represent concept subtypes and are instantiated in models. MAS designers can change the clabject properties to indicate the peculiarities of each concept subtype, depending on the particular needs. Each designer can understand models of other experts by consulting the peculiarities of concepts in models. This solution is the Inter-methodology AOML, which is supported with a graphical modeling tool. This tool is created with a model-driven development approach. This work presents this AOML as a first step of a potential standardization process in the modeling of MASs. In addition, the Ingenias Development Kit tool, an existing agent-oriented software engineering tool, is adapted to export models to the presented AOML. The proposed Inter-methodology AOML is quantitatively compared with other AOMLs in nine different problem domains, and this comparison shows that the proposed Inter-methodology AOML can determine a higher proportion of concepts in these domains than other AOMLs. The presented AOML is also evaluated and validated with its mapping to FAML.

Exploring Risk Judgments in a Trade Dispute Using Bayesian Networks

Bayesian networks (BNs) are graphical modeling tools that are generally recommended for exploring what-if scenarios, visualizing systems and problems, and for communication between stakeholders during decision making. In this article, we investigate their potential for exploring different perspectives in trade disputes. To do so, we draw on a specific case study that was arbitrated by the World Trade Organization (WTO): the Australia-New Zealand apples dispute. The dispute centered on disagreement about judgments contained within Australia's 2006 import risk analysis (IRA). We built a range of BNs of increasing complexity that modeled various approaches to undertaking IRAs, from the basic qualitative and semi-quantitative risk analyses routinely performed in government agencies, to the more complex quantitative simulation undertaken by Australia in the apples dispute. We found the BNs useful for exploring disagreements under uncertainty because they are probabilistic and transparently represent steps in the analysis. Different scenarios and evidence can easily be entered. Specifically, we explore the sensitivity of the risk output to different judgments (particularly volume of trade). Thus, we explore how BNs could usefully aid WTO dispute settlement. We conclude that BNs are preferable to basic qualitative and semi-quantitative risk analyses because they offer an accessible interface and are mathematically sound. However, most current BN modeling tools are limited compared with complex simulations, as was used in the 2006 apples IRA. Although complex simulations may be more accurate, they are a black box for stakeholders. BNs have the potential to be a transparent aid to complex decision making, but they are currently computationally limited. Recent technological software developments are promising.

A Wheel 1-Safe Petri Net Generating all the {0; 1}^n Sequences

Petri nets are a graphic and mathematic modeling tool which is applicable to several systems and to all those systems presenting particular characteristics such as concurrency, distribution, parallelism, non-determinism and/or stochastically. In this paper, a wheel Petri net whose reachability tree contains all the binary ntuples or sequences as marking vectors has been defined. The result is proved by the using of the Principle of Mathematical Induction (PMI) onjPj = n.

Personal Learning Environment

Virtual Learning Environments (VLE) have become popular in higher education in recent years due to their ability to provide additional and flexible solutions for students and researchers. However, the limitations of VLEs have led to the development of a new generation of VLE – the Personal Learning Environment (PLE). PLEs avoid these limitations and have new features that allow students to control and develop new applications, such as Web 2.0 applications and social networks. Whilst PLEs have resolved some of the drawbacks of VLEs, it is argued that PLEs also have greater potential to cover a wider range of aspects. This paper presents a proactive context-aware architecture for PLE supporting two major objectives: lifelong access and learner-centric study, covering both traditional formal (institution-based) and informal (private, non-institution-based) academic learning. Bayesian Networks are graphical modeling tools that have been used for modeling uncertain knowledge. Moreover, BN has been used in this research to implement the proposed architecture.

A New Approach to Fault Diagnosis of Power Systems Using Fuzzy Reasoning Spiking Neural P Systems

Fault diagnosis of power systems is an important task in power system operation. In this paper, fuzzy reasoning spiking neural P systems (FRSN P systems) are implemented for fault diagnosis of power systems for the first time. As a graphical modeling tool, FRSN P systems are able to represent fuzzy knowledge and perform fuzzy reasoning well. When the cause-effect relationship between candidate faulted section and protective devices is represented by the FRSN P systems, the diagnostic conclusion can be drawn by means of a simple parallel matrix based reasoning algorithm. Three different power systems are used to demonstrate the feasibility and effectiveness of the proposed fault diagnosis approach. The simulations show that the developed FRSN P systems based diagnostic model has notable characteristics of easiness in implementation, rapidity in parallel reasoning, and capability in handling uncertainties. In addition, it is independent of the scale of power system and can be used as a reliable tool for fault diagnosis of power systems.

Pseudo-Bond Graph model for the analysis of the thermal behavior of buildings

In this work, a simplified graphical modeling tool, which in some extent can be considered in halfway between detailed physical and Data driven dynamic models, has been developed. This model is based on Bond Graphs approach. This approach has the potential to display explicitly the nature of power in a building system, such as a phenomenon of storage, processing and dissipating energy such as Heating, Ventilation and Air-Conditioning (HVAC) systems. This paper represents the developed models of the two transient heat conduction problems corresponding to the most practical cases in building envelope, such as the heat transfer through vertical walls, roofs and slabs. The validation procedure consists of comparing the results obtained with this model with analytical solution. It has shown very good agreement between measured data and Bond Graphs model simulation. The Bond Graphs technique is then used to model the building dynamic thermal behavior over a single zone building structure and compared with a set of experimental data. An evaluation of indoor temperature was carried out in order to check our Bond Graphs model.

Graphical modeling and simulation of discrete-event systems with CD++Builder

We introduce CD++Builder, an open-source environment that aims at providing easy-to-use graphical modeling tools to simplify the construction of models and the execution of simulations of complex Discrete Event System Specification (DEVS) models. The architecture and implementation of CD++Builder focuses on providing simple definition and reuse of components, offering easy extensibility to support new features. CD++Builder includes graphical editors for DEVS-coupled models, DEVS-Graphs and C++ atomic models; it provides code templates that are synchronized with their graphical versions, and it greatly simplifies the software installation and update procedures. We show how this environment can be used to build and simulate DEVS models, and we compare the process with previous versions and other simulation tools, showing that CD++Builder can improve model development by creating DEVS models in a completely assisted manner, including advanced graphical interfaces.

PPModel: a modeling tool for source code maintenance and optimization of parallel programs

As the computation power in desktops advances, parallel programming has emerged as one of the essential skills needed by next generation software engineers. However, programs written in popular parallel programming paradigms have a substantial amount of sequential code mixed with the parallel code. Several such versions supporting different platforms are necessary to find the optimum version of the program for the available resources and problem size. As revealed by our study on benchmark programs, sequential code is often duplicated in these versions. This can affect code comprehensibility and re-usability of the software. In this paper, we discuss a framework named PPModel, which is designed and implemented to free programmers from these scenarios. Using PPModel, a programmer can separate parallel blocks in a program, map these blocks to various platforms, and re-execute the entire program. We provide a graphical modeling tool (PPModel) intended for Eclipse users and a Domain-Specific Language (tPPModel) for non-Eclipse users to facilitate the separation, the mapping, and the re-execution. This is illustrated with a case study from a benchmark program, which involves re-targeting a parallel block to CUDA and another parallel block to OpenMP. The modified program gave almost 5× performance gain compared to the sequential counterpart, and 1.5× gain compared to the existing OpenMP version.

Methodologies for supervision of Hybrid Energy Sources based on Storage Systems – A survey

Hybrid Energy Sources based on Storage Systems (HES) are increasingly used to improve the grid integration of renewable energy generators, or to improve the energy efficiency and the reliability of transport systems. This paper proposes a survey on the methodologies to design fuzzy logic based supervision strategies of this new kind of energy generating systems. Different ways to manage energy storage system are particularly discussed.A graphical modeling tool is used to facilitate the analysis and the determination of fuzzy control algorithms adapted to complex hybrid systems. The methodology is divided in different steps covering the design of a supervisor from the system work specifications to an optimized implementation of the control.An Experimental Design Methodology (EDM) combined with optimization algorithms is used to tune a set of parameters suitable for a fuzzy supervisor in order to optimize power, energy, efficiency, voltage quality, economic or environmental indicators.The application of this methodology to the supervision of different topologies of HES, based on renewable energy in a grid or in building applications or dedicated to transport systems, illustrates the performance and the systematic dimension of the approach.