Object-oriented Modeling Framework Research Articles

Parallel Simulation of The Electromechanical Transient Phenomena of Power System via Modern Software Development Technique

The simulation of power system electromechanical transient phenomena is highly dependent on the knowledge and model of special domain. For this reason, traditional parallelization of the simulation must be coupled with concrete algorithm and code. In this paper, a parallelized electromechanical transient simulation program is proposed based on the open-source simulation engine called InterPSS and general open object-oriented modelling framework. The correctness and effectiveness of this framework have been verified by a large-scale simulation case.

Flexible watershed simulation with the Raven hydrological modelling framework

A general formulation of a surface water hydrological model is posed that enables multiple numerical schemes, model structures, discretization schemes, and interpolation approaches to be tested, compared, and/or used for assessment of structural uncertainty and algorithm skill. This formulation is the basis for the object-oriented and open source hydrological modelling framework Raven. Raven is uniquely capable of fully emulating and then modifying or extending a number of existing hydrological models of differing design, including the UBC watershed model, GR4J, MOHYSE, HMETS, and HBV-EC. More than 100 compatible process algorithm options and more than 80 interchangeable options for both routing and the estimation of forcings support the testing of trillions of possible model configurations. It supports general spatial discretization, including grids, subbasin/hydrologic response units, lumped, or triangulated irregular network models. Raven’s utility for examining the impact of model choices and sensitivity to structural model uncertainty is demonstrated with a set of simple test cases.

Process Innovation and Improvement Using Business Object-Oriented Process Modelling (BOOPM) Framework

In the past decades, a number of methodologies have been proposed to innovate and improve business processes that play an important role in enhancing the operational efficiency of an organisation in order to attain business competitiveness. Traditional business process modelling (BPM) approaches are process-centric and focus on the workflow, ignoring the data modelling aspects that are essential for today’s data-centric landscape of modern businesses. Hence, a majority of BPM initiatives have failed in several organisations due to the lack of data-driven insights into their business performance. On the other hand, the information systems of today focus more on dataflows using object-oriented modelling (OOM) approaches. Even standard OOM approaches, such as unified modelling language (UML) methods, exhibit inherent weaknesses due to their lack of formalized innovation with business objects and the dynamic control-flows of complex business processes. In addition to these issues, both BPM and OOM approaches have been augmented with an array of complex software tools and techniques which have confused businesses. There is a lack of a common generalized framework that integrates the well-formalised control-flow based BPM approach and the dataflow based OOM approach that is suitable for today’s enterprise systems in order to support organisations to achieve successful business process improvements. This paper takes a modest step to fill this gap. We propose a framework using a structured six-step business process modelling (BPM) guideline combined with a business object-oriented methodology (BOOM) in a unique and practical way that could be adopted for improving an organisation’s process efficiency and business performance in contemporary enterprise systems. Our proposed business object-oriented process modelling (BOOPM) framework is applied to a business case study in order to demonstrate the practical implementation and process efficiency improvements that can be achieved in enterprise systems using such a structured and integrated approach.

Sub-zonal computational fluid dynamics in an object-oriented modelling framework

Airflow modelling is of fundamental importance for evaluating ventilation performance and energy consumption in buildings, and various approaches to the problem—starting from purely empirical up to the CFD ones—have been proposed and evaluated in the past years. Moreover, since the ultimate goal is whole building modelling, airflow simulation needs coupling with Energy Simulation (ES), in order to assess the overall energy performance. Due to the substantial differences between the software employed for airflow and ES, co-simulation is very often felt as the only way to handle such a problem. For example, in recent years a lot of effort has been spent in to couple ES and CFD tools. This paper proposes an alternative, in the form of an approach for solving the Navier-Stokes equations in a general multi-domain modelling framework. Since co-simulation is not involved, the correctness of the numerical solution relies on a single solver, thus being really transparent to the analyst. This is a first step towards a whole building simulation tool embedded in a unique framework capable of performing energy analysis, computing airflows, and representing control systems.

Solutions of JDF-Workflow Scheduling Problem using Genetic Algorithm

In print media industries networked production requires advanced print and media specific job definitions and the communication carrying job relevant information alongside the complete production chain. The relatively young XML based communication standard JDF/JMF allows to specify workflow models and data exchange.Based on an object-oriented approach, a scheduling and modeling framework is proposed, which implements modules for the resources and controls applied in this particular industry. For this framework the available JGAP library is extended to enable modeling of networked print production using the same JDF- /JMF-communication algorithms as applied in the real production. This leads toward a realization of JDF Workflow for operation planning and control of networked print production in digital printing factory environment. This paper theoretically describes and defines a method of expression for execution sequence of JDF Process Nodes and Process Group Nodes using Hierarchical Dependence Graph, meanwhile generates the Connectivity Matrix for practical use. In order to prepare the Device data for scheduling software, a small database has been set up, with functions to manage Device resources.The resolves of limited scheduling problems in the field of traditional and digital printing workflows using genetic algorithm may present its basic principle and algorithms for calculation of Connectivity Matrix of JDF nodes, this shall lead to adding more limitations to broader applications in solving print shop scheduling problems.

Proposal of a Python interface to OpenMI, as the base for open source hydrological framework

Hydrologists need simple, yet powerful, open source framework for developing and testing mathematical models. Such framework should ensure long-term interoperability and high scalability. This can be done by implementation of the existing, already tested standards. At the moment two interesting options exist: Open Modelling Interface (OpenMI) and Object Modeling System (OMS). OpenMI was developed within the Fifth European Framework Programme for integrated watershed management, described in the Water Framework Directive. OpenMI interfaces are available for the C# and Java programming languages. OpenMI Association is now in the process of agreement with Open Geospatial Consortium (OGC), so the spatial standards existing in OpenMI 2.0 should be better implemented in the future. The OMS project is pure Java, object-oriented modeling framework coordinated by the U.S. Department of Agriculture. Big advantage of OMS compared to OpenMI is its simplicity of implementation. On the other hand, OpenMI seems to be more powerful and better suited for hydrological models. Finally, OpenMI model was selected as the base interface for the proposed open source hydrological framework. The existing hydrological libraries and models focus usually on just one GIS package (HydroFOSS – GRASS) or one operating system (HydroDesktop – Microsoft Windows). The new hydrological framework should break those limitations. To make hydrological models’ implementation as easy as possible, the framework should be based on a simple, high-level computer language. Low and mid-level languages, like Java (SEXTANTE) or C (GRASS, SAGA) were excluded, as too complicated for regular hydrologist. From popular, high-level languages, Python seems to be a good choice. Leading GIS desktop applications – GRASS and QGIS – use Python as second native language, providing well documented API. This way, a Python-based hydrological library could be easily integrated with any GIS package supporting this programming language. As the OpenMI 2.0 standard supported interfaces only for Java and C#, the Python interface for OpenMI standard, presented in this paper, is the first step done towards the open and interoperable hydrological framework. GIS-related issues of the OpenMI 2.0 standard are also outlined and discussed.

Real-time models for wheels and tyres in an object-oriented modelling framework

This article presents models for wheels and tyres in the application field of real-time multi-body systems. For this rather broad class of applications it is difficult to foresee the right level of model complexity that is affordable in a specific simulation. Therefore we developed a tyre model that is adjustable in its degree of complexity. It consists of a list of stepwise developed sub-models, each at a higher level of complexity. These models include semi-empirical equations. The stepwise development process is also reflected in the corresponding implementation with the modelling language Modelica. The final wheel model represents a supermodel and enables users to select the right level of complexity in an unambiguous way.

An object-oriented modelling framework for the arterial wall

An object-oriented modelling framework for the arterial wall is presented. The novelty of the framework is the possibility to generate customisable artery models, taking advantage of imaging technology. In our knowledge, this is the first object-oriented modelling framework for the arterial wall. Existing models do not allow close structural mapping with arterial microstructure as in the object-oriented framework. In the implemented model, passive behaviour of the arterial wall was considered and the tunica adventitia was the objective system. As verification, a model of an arterial segment was generated. In order to simulate its deformation, a matrix structural mechanics simulator was implemented. Two simulations were conducted, one for an axial loading test and other for a pressure–volume test. Each simulation began with a sensitivity analysis in order to determinate the best parameter combination and to compare the results with analogue controls. In both cases, the simulated results closely reproduced qualitatively and quantitatively the analogue control plots.

A Hierarchical Object-oriented Functional Modeling Framework for Co-Design of Mechatronic Products

The existing co-design methods of mechatronic products focus on co-design of mechanical and electronic components or co-design of computer hardware and software components. There exist no effective co-design methods for mechanical, electronic, and software components. This article proposes an integrated object-oriented and functional decomposition framework, developed for co-design and co-analysis of product functions, structures, and their mapping relations in a top-down manner. The framework has three operational models: Function Model, Object Model, and Information Flow Model. The function model is implemented as a function tree (FT), which is a hierarchical structure for the functional decomposition and behavioral analysis of the product under functional domain commonly used in classical engineering design. The object model is a high order object model (HOOM) designed for system and component decomposition for analysis and design of the structure of a system and its components under physical domain. The information flow model is a function and object mapping model, which describes and analyzes implementation parameters and mapping relations between FT functions and HOOM objects. These three models are decomposed and constructed level-by-level and side-by-side to form the concurrent and coordinated design paradigm for the product design team. The components of the resulting design are then carefully reviewed and summarized in a design summary and task assignment table by the product design team, and assigned to their respective disciplinary engineers for detail design or implementation according to their attributes. The proposed methodology enables mechanical, electronic, and software engineers to develop mechatronic products concurrently in a seamlessly integrated fashion.

Object-oriented modelling for spacecraft dynamics: Tools and applications

The development process for spacecraft control systems relies heavily on modelling and simulation tools for spacecraft dynamics. For this reason, there is an increasing need for adequate design tools in order to cope efficiently with tightening budgets for space missions. The paper discusses the main issues related to the modelling and simulation of satellite dynamics for control purposes, and then presents an object-oriented modelling framework, implemented as a Modelica library. The proposed approach allows a unified approach to a range of problems spanning from initial mission design and actuator sizing phases, down to detailed closed-loop simulation of the control system, including realistic models of sensors and actuators. It also promotes the reuse of modelling knowledge among similar missions, thus minimizing the design effort for any new project. The proposed framework and the Modelica library are demonstrated by several illustrative case studies.

An object-oriented modeling framework for representing uncertainty in early variant design

This article presents a framework for the representation of uncertainty in the early design of complex adaptive products such as automobiles. The core of the framework is an object-oriented approach in which design objects and their inter-relationships may be modeled, and in which both the design attributes and the product structure may be uncertain. Relationship objects allow product variants and design alternatives to be represented. In addition to the design model, derivation methods for design attributes may be modeled, and methods may be incorporated to allow the deterministic or probabilistic computation of attributes. The modeling framework is the basis of a risk modeling tool, RiTo, in which Monte Carlo simulation is used to compute estimates for costs and other design attributes together with their probability of achievement in the final design. Uncertainties may be aggregated and levels of uncertainty in different parts of the model may be continually analysed and assessed. The framework also provides a mechanism for accumulating product knowledge, in particular knowledge concerning relationships between elements of part and assembly models, product volumes and manufacturing considerations.

An experimental object-oriented modelling of an hydraulic valley

This communication presents an object-oriented modelling methodology for the development of complex systems simulators and an application to an hydroelectric system. The model structure is described by a multiport object-oriented diagram. Its implementation and simulation are based on the object-oriented modelling language Modelica© and on a multiformalism simulation platform Dymola©. System identification techniques arc used for both estimating the behavioural models of objects and for the calibration of the multiport diagram. The originality of this contribution is the introduction of the behavioural formalism of the systems theory in the object-oriented modelling framework.

A Multiport Object-Oriented Diagram for Batch Process Modelling

This article presents a computer-aided method for batch system modelling and simulation. Several modelling techniques like the behavioural formalism of system theory, the SP88-ASTRID decomposition model, UML class diagram and energy flow diagrams have been integrated in an object-oriented modelling framework to constitute a modular and hierarchical model structure entitled: Multiport Object-Oriented Diagram. The implementation of this diagram is supported by the physical modelling language: Modelica© and its simulation has been Performed in Dymola©. An application to a simple batch process exhibits the main interesting aspects of this approach.

Efficient Query Execution Techniques in a 4DIS Video Database System for eLearning

In this paper, we describe our work on developing an eLearning video database system. The eLearning video database provides a temporal modeling framework for describing eLearning video data and it supports data distribution by applying vertical class partitioning techniques. Building on top of our previous work on Four Dimensional Information System (4DIS)—an object-oriented temporal modeling framework, we apply vertical class partitioning techniques onto a 4DIS eLearning video database system as a means for efficient query execution. We further describe our work on dynamic fetching of multimedia eLearning video on the Internet. A detailed cost model for query execution through vertical class partitioning is developed. Finally, we demonstrate through the use of a running example the effectiveness of our vertical class partitioning approach.

An object-oriented data framework for virtual environments with hierarchical modeling

Virtual reality technology, which is cyberspace composed of multimedia, is a field of comprehensive technology. It is of three basic feathers, namely, interaction, immersion and imagination so that we have to cope with the need for extremely large data sets, massive amounts of computation, and high-throughput networking. This paper presents an approach for object-oriented data modeling framework of complicated virtual environments. The paper discusses the hierarchical decomposition of objects in virtual environments and reuse of these object data libraries to constitute model of virtual environments. This modeling approach used in the paper makes sure that modeling data can be inherited, modularized, maintained easily so as to control redundant data and reduce the software development time, at the same time, realizes dynamic behaviors of objects to meet the needs of some changes of virtual environments.

A physiologically based model of pest–natural enemy interactions

The population dynamic processes in aphids and mites are very similar, because the two groups show strong similarities in their biology. Resource limitation, density-dependent emigration and natural enemies are major factors controlling aphid and mite populations, but an assessment of their relative importance has proven difficult. We used a physiologically based simulation model to investigate the relative impact of the three factors on aphid pest populations. The present simulation model includes winter wheat, three aphid species, Metopolophium dirhodum (Wlk.), Rhopalosiphum padi (L.) and Sitobion avenae (F.) (Hom.: Aphididae) and three parasitoids, Aphelinus abdominalis Dalman (Hym.: Apheliniidae), Aphidius rhopalosiphi De Stefani-Perez and Praon volucre (Hal.) (Hym.: Aphidiidae). We derived and parameterized the model from literature data and validated it against independent field data. The study showed that resource limitation and density-dependent alate production restricts aphid numbers in the field. The mortality due to parasitoids increased late in the season and reduced the peak aphid numbers only moderately. The modelling approach we used is appropriate for simulating other pest–natural enemy systems, such as the spider mite–predatory mite system. Using an object-oriented modelling framework as a template, acarologists can now efficiently develop the simulation model of their choice.

An object-oriented modelling framework for automated manufacturing system

Proposed in the paper is an object-oriented modelling OOM framework, called a JR-net modelling framework, for automated manufacturing system AMS design. The proposed modelling framework, which consists of a graphical modelling tool called JR-net job resource relation-net and a modelling building procedure, is the same as the current practice of AMS design and is based on the OOM paradigm. In other words, a virtual prototype of AMS is constructed step-by-step based on a three-phase modelling approach: Static layout modelling object model ; job flow modelling functional JR-net model ; supervisory control modelling dynamic model . A functional JR-net model is a directed graph in which the standard resources of an AMS become nodes and job transfers among the resources become the arcs of the graph. A complete dynamic JR-net model is obtained by specifying supervisory control requirements using tokens in the functional JR-net model. The usefulness of the proposed OOM framework is demonstrated by applying it to the modelling of an AS RS. Also addressed are implementation issues of JR-net models.

Efficient multicast routing in high speed networks

This paper presents two algorithms: for a minimal cost shared multicast tree construction (MCTC), and for a scalable multicast session call establishment, called multicast tree development (MCTD). Both algorithms are of original design based on a network simplex presentation, providing a new effective approach to the MCTC, and an object-oriented modelling framework providing the highest scalability for sparse groups with high dynamics of membership, different quality of service requirements and multiple senders. A new approach is proposed for the MCT construction-bidirectional growing of the MCT without pruning; instead the MCTD makes use of extra branches to improve reliability and advertise new receivers.

An object-oriented modeling framework for sawmill simulation

This paper describes a flexible, general-purpose simulation environment for sawmill modeling and analysis. The system represents a library of objects developed in an object-oriented framework. The objective is to develop a system that can be used to mode different sawmill configurations, to identify manufacturing process constraints, and to evaluate control strategies and management practices.

Synthesis of operating procedures for complete chemical plants—I. Hierarchical, structured modelling for nonlinear planning

Modelling issues associated with the synthesis of process operations on a plant-wide scale are discussed, and a hierarchical, distributed, object-oriented modelling framework described. The modelling approach is generic, and is demonstrated to be suitable for computer-automation of the synthesis of operating procedures. In Part II, provably correct and complete nonlinear planning algorithms based on these models are presented. It is shown that domain-independent planning methodologies using the functional operators required for the synthesis of operating procedures are computationally intractable. Consequently, domain-specific knowledge is exploited within the modelling structure presented in this paper in order to define a tractable methodology for nonlinear planning of process operations. In this paper, we have discussed some of the issues involved in automating the synthesis of plant-wide operating procedures for continuous chemical process. In particular, we have focussed on the question of how to effectively model, on the computer, knowledge about the operation of chemical plants. Previous attempts at modelling have either relied on the restrictive operator- based modelling paradigm, or have employed extremely simplified or situation-specific models. A modelling technique based on a functional operator structure was also considered. This representation accounted for the fact that the outcome of applying an operator is dependent upon the state of the system before execution, and was shown to reduce to the conditional action scheme investigated by researchers in artificial intelligence. Planning with conditional operators involves a plan generation step which is NP-hard, and is therefore considered to be computationally intractable. This justifies the adoption of a domain-specific approach to the planning of process operations, and explains why no algorithmic solution has yet been developed. Realizing the limitations of the operator model, a hierarchical, distributed, object-oriented modelling structure was described. The models are expressive enough to allow for automatic generation of interunit constraints, which is accomplished through propagation of known values through a network of relations representing the physical laws governing the behavior of a chemical plant and constraints induced by practical engineering considerations. The modelling framework is sufficiently general so as to allow the use of both quantitative information as well as qualitative knowledge, such as order-of-magnitude estimates. Examples of the construction and use of the hierarchical modelling structure were presented, and implementational issues discussed. The nonlinear planning methodology that makes use of the modelling structures described here is presented in Part II of this series.