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Java classes for nonprocedural variogram modeling

COMPUTERS & GEOSCIENCES 2002年第3期28卷 387-397页

作者： Faulkner, BR US EPA Natl Risk Management Lab Subsurface Protect & Remediat Div Ada OK 74820 USA

A set of Java(TM) classes was written for variogram modeling to support research for US EPA's Regional Vulnerability Assessment Program (ReVA). The modeling objectives of this research program are to use conceptual programming tools for numerical analysis for regional risk assessment. The classes presented use of object-oriented design elements, and their use is described for the benefit of programmers. To help facilitate their use, class diagrams and standard JavaDoc commenting were employed, Java's support for polymorphism and inheritance is used and these are described as ways to promote extension of these classes for other geostatistical applications. Among the advantages is the case of programming, code reuse, and conceptual, rather than procedural implementation. A graphical application for variogram modeling that uses the classes is also provided and described. It can also be used by non-programmers. This application uses a generalized least-squares fitting algorithm for robust parametric variogram model fitting through the variogram cloud. This feature makes this program unique from other freely available variogram modeling programs, though the classes are presented primarily so they may be extended for use in other Java programs. More traditional variogram plotting and fitting utilities are also provided. This application is graphical and platform-neutral. It uses classes of the recently proposed Java API for linear algebra, called the JAMA package. Published by Elsevier Science Ltd.

关键词： object-oriented modeling ReVA iteratively reweighted least squares multi-disciplinary modeling JAMA variogram cloud

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Dynamic modeling of IGCC power plants

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APPLIED THERMAL ENGINEERING 2012年第1期35卷 91-111页

作者： Casella, F. Colonna, P. Delft Univ Technol Energy Technol Sect Proc & Energy Dept NL-2628 CA Delft Netherlands Politecn Milan Dipartimento Elettron & Informaz I-20133 Milan Italy

Integrated Gasification Combined Cycle (IGCC) power plants are an effective option to reduce emissions and implement carbon-dioxide sequestration. The combination of a very complex fuel-processing plant and a combined cycle power station leads to challenging problems as far as dynamic operation is concerned. Dynamic performance is extremely relevant because recent developments in the electricity market push toward an ever more flexible and varying operation of power plants. A dynamic model of the entire system and models of its sub-systems are indispensable tools in order to perform computer simulations aimed at process and control design. This paper presents the development of the lumped-parameters dynamic model of an entrained-flow gasifier, with special emphasis on the modeling approach. The model is implemented into software by means of the Modelica language and validated by comparison with one set of data related to the steady operation of the gasifier of the Buggenum power station in the Netherlands. Furthermore, in order to demonstrate the potential of the proposed modeling approach and the use of simulation for control design purposes, a complete model of an exemplary IGCC power plant, including its control system, has been developed, by re-using existing models of combined cycle plant components;the results of a load dispatch ramp simulation are presented and shortly discussed. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： Dynamic modeling IGCC object-oriented modeling Modelica Gasification

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modeling of hybrid control systems using the DEVSLib Modelica library

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CONTROL ENGINEERING PRACTICE 2012年第1期20卷 24-34页

作者： Sanz, Victorino Urquia, Alfonso Cellier, Francois E. Dormido, Sebastian UNED ETSI Informat Dpto Informat & Automat Madrid 28040 Spain ETH Dept Comp Sci CH-8092 Zurich Switzerland

DEVSLib is a free Modelica library, developed by the authors, that supports the Parallel DEVS formalism. The library is mainly designed to model discrete-event systems. It also includes interfaces to communicate the DEVSLib models with the rest of the Modelica libraries. Thus, the library can be used in the development of multi-domain and multi-formalism hybrid models using the object-oriented methodology supported by Modelica. This manuscript presents the hybrid system modeling capabilities included in DEVSLib. In particular, these functionalities are applied to the description of hybrid control systems. A case study of a supermarket refrigeration system, using the traditional control approach, is discussed. Three implementations of the plant and its controllers have been developed and are described. The system is simulated reproducing the day and night conditions, and the results from the three implementations are compared. DEVSLib is freely available for download at http://***. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： object-oriented modeling Hybrid control Modelica Parallel DEVS

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Dynamic modeling and simulation of a double-effect absorption heat pump

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INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID 2016年 72卷 171-191页

作者： de la Calle, Alberto Roca, Lidia Bonilla, Javier Palenzuela, Patricia CSIRO Energy 10 Murray Dwyer Ct Mayfield West NSW 2304 Australia Univ Almeria UAL CIEMAT Joint Ctr CIESOL Res Ctr Solar Energy Ctra Sacramento S-N Almeria 04120 Spain CIEMAT Plataforma Solar Almeria Ctra Senes S-N Tabernas 04200 Almeria Spain

This paper presents a new dynamic model to study the transient thermochemical behavior of a double-effect absorption heat pump (DEAHP). It has been designed according to the experience with an experimental DEAHP totally integrated into a solar-assisted multi-effect distillation (MED) plant set up at CIEMAT - Plataforma Solar de Almeria (PSA). The non-linear first-principles model was implemented using the equation-based object-oriented Modelica modeling language and is based on a mathematical formulation that describes the main heat and mass transfer phenomena in this kind of facilities. A modular and hierarchical modeling methodology has allowed a graphical modeling development. Submodels that wrap the different physical phenomena are interconnected between them, thus making a three level deep hierarchy. All the submodels have been calibrated and validated with experimental data. The numerical predictions show a good agreement with measured data. Crown Copyright (C) 2016 Published by Elsevier Ltd. All rights reserved.

关键词： Lithium bromide Phase transitions Falling film object-oriented modeling Modelica

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FAST SIMULATION OF OPEN QUEUING-SYSTEMS

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SIMULATION 1995年第3期65卷 183-190页

作者： HUNT, CS FOOTE, BL UNIV OKLAHOMA SCH IND ENGNNORMANOK 73019

We describe a technique developed by the authors for fast simulation of open queuing networks. The technique takes advantage of the recursive nature of departure times of customers in various parts of the system. The event calender is circumvented using these recursive relationships whenever possible. A framework for identifying these recursive aspects of a network is presented. The technique involves identifying the servers in the system at which flows merge or diverge. Knowledge about the merge and diverge points customer has with other customers at each point in the system. The concept of a system level is based on these dependency relationships. The technique is implemented in the object oriented language Small Talk 80. The implementation utilizes Windows interfaces and allows graphical analysis of the simulation results. The implementation is shown to achieve significant reductions in execution time compared with the traditional discrete-event approach to simulation of such networks in most cases. Several different types of systems are explored in an attempt to characterize those systems on which the technique functions well.

关键词： FAST SIMULATION QUEUING SYSTEMS object-oriented modeling

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Multi-Stage Quadratic Flexible Optimal Power Flow With a Rolling Horizon

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IEEE TRANSACTIONS ON SMART GRID 2021年第4期12卷 3128-3137页

作者： Zhong, Chiyang Meliopoulos, A. P. Sakis Xie, Boqi Xie, Jiahao Liu, Kaiyu Georgia Inst Technol Sch Elect & Comp Engn Atlanta GA 30332 USA Entergy Corp Enterprise Planning New Orleans LA 70113 USA

Optimal power flow (OPF) has always played an important role in optimizing the operation of power systems, which are complex and highly nonlinear networks. The need for optimization is even more pressing in modern power grids with distributed energy resources (DERs, with or without storage) that introduce more flexibility, dynamics, and uncertainties to power grids. Most importantly, they add the time dimension to the optimization process: DERs generate the need to optimize systems in real time over a time horizon considering forecasts. This article proposes a multi-stage OPF formulation and solution method based on object-oriented device models with a rolling horizon incorporated for real-time optimizations to achieve optimal feedback control. The process also takes into account changing forecasts. The proposed approach is tested on a real distribution feeder and the results indicate that the method is very promising.

关键词： Mathematical model object oriented modeling Optimization Load flow Predictive models Power systems Real-time systems Distributed energy resources forecasts multi-stage optimal power flow object-oriented modeling rolling horizon sequential linear programming

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Ownership as a conceptual modeling construct

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DATA & KNOWLEDGE ENGINEERING 2007年第2期62卷 248-273页

作者： Halper, Michael Liu, Li-Min Geller, James Perl, Yehoshua Kean Univ Dept Math & Comp Sci Union NJ 07083 USA Chung Yuan Christian Univ Dept Appl Math Chungli Taiwan New Jersey Inst Technol CS Dept Newark NJ 07102 USA

Ownership is a relationship that pervades many aspects of our lives, from the personal to the economic, and is particularly important in the realm of the emerging electronic economy. As it is understood on an intuitive level, ownership exhibits a great deal of complexity and carries a rich semantics with respect both to the owner and the possession. A formal model of an ownership relationship that inherently captures varied ownership semantics is presented. This ownership relationship expands the repertoire of available conceptual data modeling primitives. It is built up from a set of characteristic dimensions, namely, exclusiveness, dependency, documentation, transferability, and inheritance, each of which focuses on a specific aspect of ownership semantics. The data modeler has the ability to make a variety of choices along these five dimensions, and thus has access to a wide range of available ownership features in a declarative fashion. These choices ultimately impose various constraints (specified in OCL) on the states of data objects and their respective ownership activities, including transactions such as acquiring and relinquishing ownership. To complement the formal aspects of the ownership model and enhance its usability, we present a graphical ownership notation that augments the Unified modeling Language (UML) class diagram formalism. An implementation of the ownership relationship in a commercial object-oriented database system is discussed. (c) 2006 Elsevier B.V. All rights reserved.

关键词： ownership relationship semantic relationship ownership semantics conceptual modeling object-oriented modeling object-oriented database system electronic commerce

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MSEMT: An Advanced Modelica Library for Power System Electromagnetic Transient Studies

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IEEE TRANSACTIONS ON POWER DELIVERY 2022年第4期37卷 2453-2463页

作者： Masoom, Alireza Mahseredjian, Jean Ould-Bachir, Tarek Guironnet, Adrien Polytech Montreal Dept Elect Engn Montreal PQ H3T 1J4 Canada Polytech Montreal Dept Comp & Software Engn Montreal PQ H3T 1J4 Canada Reseau Transport Elect RTE R&D Dept Paris France

Electromagnetic Transient (EMT) simulation tools are typically developed using conventional procedural programming languages. On the other hand, modern high-level and equation-based programming languages, such as Modelica, are currently available. Modelica allows formulating models that are easy to develop, maintain and understand by expressing what needs to be computed without stating how it should be computed. This paper presents a Modelica-based simulator for electromagnetic transients. It is demonstrated that this approach offers significant advantages for developing sophisticated models. Computational performance and accuracy are compared to a conventional EMT-type simulation tool.

关键词： Mathematical model object oriented modeling Numerical models Computational modeling Integrated circuit modeling Inductors Codes Declarative modeling equation-based modeling object-oriented modeling MSEMT library modelica EMT-type simulation power system transients

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Advanced GNC-oriented modeling and simulation of Vertical Landing vehicles with fuel slosh dynamics

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ACTA ASTRONAUTICA 2023年第1期204卷 294-306页

作者： Fari, Stefano Seelbinder, David Theil, Stephan German Aerosp Ctr DLR Inst Space Syst Nav & Control Syst Dept Robert Hooke Str 7 Bremen Germany

This paper introduces a flexible framework to enable high-fidelity simulations of the fuel slosh dynamics for verification of the Guidance, Navigation and Control (GNC) algorithms. The sloshing phenomenon must be tackled during the control system design phase and the GNC software run and validated within appropriate simulation frameworks. Equivalent mechanical models can well approximate sloshing under specific assump-tions, allowing the derivation of the multibody vehicle's equations of motion;however, while suitable for analysis and control synthesis purposes, this approach presents several limitations for implementation as a simulation model. In this work, the multibody plant embedding slosh dynamics is modeled by means of the DLR's Vertical Landing Vehicles Library (VLVLib) written using the object-oriented Modelica modeling language. The advantages of using Modelica are explored throughout the paper. Given that control synthesis, analyses and simulation campaigns are usually performed in the Matlab/Simulink environment, a core point of the proposed solution is to achieve a good synergy within the latter and the Modelica plant model with the least readaptation burden for the developer. The strategies to achieve a full integration and verification tool chain are illustrated. The potential of this approach is demonstrated via two different test cases: a lunar landing scenario of the ALINA spacecraft developed by PTS, and CALLISTO reusable rocket demonstrator.

关键词： Slosh dynamics Modelica object-oriented modeling Simulation GNC Vertical landing vehicle Lunar lander Reusable launch vehicle

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An integrated modeling approach for shop-floor scheduling and control problem of flexible manufacturing systems

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INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY 2012年第9-12期59卷 1127-1142页

作者： Tuncel, Gonca Dokuz Eylul Univ Dept Ind Engn TR-35160 Buca Izmir Turkey

Increasing automation and complexity of today's production systems affect the constraints of real-world shop-floor control and scheduling problems. To deal with these constraints, either the existing modeling and analysis techniques were improved or new scheduling approaches were developed. This study attempts to propose an object-oriented approach for modeling and analysis of shop-floor scheduling problem of flexible manufacturing systems (FMSs) using high-level Petri Nets (PNs). The graphical nature and mathematical foundation has made PN-based methods appealing in real-time scheduling and control of FMSs. In the proposed approach, we firstly construct an object-modeling diagram of an FMS and develop a heuristic rule-base to solve the resource contention problem then formulate the dynamic behavior of the system by high-level PNs. The modeling methodology is illustrated by an FMS, and the proposed rule-based system is compared with several dispatching rules with respect to part flow time and tardiness-related performance measures.

关键词： Flexible manufacturing systems Shop-floor scheduling Petri nets object-oriented modeling

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