Specifying and proving properties of timed I/O automata using Tempo

Timed I/O automata (TIOA) is a mathematical framework for modeling and verification of distributed systems that involve discrete and continuous dynamics. TIOA can be used for example, to model a real-time software component controlling a physical process. The TIOA model is sufficiently general to subsume other models in use for timed systems. The Tempo Toolset, currently under development, is aimed at supporting system development based on TIOA specifications. The Tempo Toolset is an extension of the IOA toolkit, which provides a specification simulator, a code generator, and both model checking and theorem proving support for analyzing specifications. This paper focuses on the modeling of timed systems and their properties with TIOA and on the use of TAME4TIOA, the TAME (Timed Automata Modeling Environment) based theorem proving support provided in Tempo, for proving system properties, including timing properties. Several examples are provided by way of illustration.     

S函数建模和仿真过程的研究

Simulink支持各种动态系统的建模仿真。S函数是整个Simulink动态系统的核心,通过S函数可将系统的数学方程表达式与方框图表达形式联系起来。探讨了S函数的建模和仿真问题,研究在S函数中使用M文本方式输入公式、方程,非常适合复杂动态系统的数学描述。用Simulink模块库中传递函数模块作对编写的M文件S函数模块与了对比实验,并对编制调试好S函数进行了编译,编译后的S函数通过了仿真速度测试脚本文件,结果验证了编译后S函数的仿真执行速度大致会提高了一倍。     

A New Approach for Modeling Inconsistencies in Digital-Assisted Analog Design

Safety critical circuits and systems require a specified function and real world structure to match each other. At the same time the functionality and the structure become more and more complex. This results in a high effort for design verification and test such that specification-oriented testing is getting more and more under pressure. In this paper we offer an approach to warrant the match between a specification and its structure by invertibly composing the corresponding “fingerprint” model. Conversely, the fingerprint warrants the match between specification and structure. We present a theoretical framework for creating the fingerprint from the specification and the structure, respectively, and demonstrate the parallel composition of fingerprints to an overall asynchronous feedback circuit system.     

Hybrid systems modeling for power systems

In this work a framework for modeling power systems using hybrid input/output automata (HIOA) is proposed. The system is assumed to consist of several distinct components. Some of them drive the continuous dynamics while others exhibit event-driven discrete dynamics. Such behavior is characterized by interactions between continuous dynamics and discrete events. Therefore the power systems are an important example of hybrid systems. This hybrid modeling process is applied to a simple power system.     

基于Matlab/Simulink的风光柴储发电系统仿真

随着新能源发电技术和储能技术的日趋成熟,风光柴储混合发电系统越来越具有竞争力。本文基于Matlab/Simulink仿真平台搭建了小功率离网型风光柴储混合发电系统的模型,并且实现了根据气象条件和蓄电池荷电量等的变化,合理调节能量流动,分配各功率模块的有功功率输出。详细阐述了混合发电系统的建模与仿真方法,可为电气相关专业的建模仿真提供参考。     

An approach to rollback recovery of collaborating mobile agents

Fault-tolerance is one of the main problems that must be resolved to improve the adoption of the agents' computing paradigm. In this paper, we analyze the execution model of agent platforms and the significance of the faults affecting their constituent components on the reliable execution of agent-based applications, in order to develop a pragmatic framework for agent systems fault-tolerance. The developed framework deploys a communication-pairs independent checkpointing strategy to offer a low-cost, application-transparent model for reliable agent-based computing that covers all possible faults that might invalidate reliable agent execution, migration and communication and maintains the exactly-once execution property.     

基于MATLAB软件的船载云台控制系统设计

介绍了船载云台的特点和应用范围,对其指标要求、稳定误差分析和控制系统框架进行了分析说明。详细叙述了MATLAB软件进行系统建模、性能分析以及该软件环境下的Simulink仿真工具进行稳定精度仿真的方法和步骤。实际试验表明仿真的结果与实际效果基本一致。该设计过程表明,使用MATLAB软件可以大大缩短设计时间,减少风险。该设计方法对类似的稳定系统设计具有借鉴意义。     

Interfacing Software Libraries from Nondeterministic Prototypes

Modeling software systems is one of the most obvious uses of a formal specification language. A software prototype, automatically generated from the specification, enables the developer to validate the system in a real environment. However, real software systems are seldom developed from scratch, but rather built using existing libraries. In this paper, we show how a program based on existing software libraries is modeled in the Concurrent Object-Oriented Petri Net specification language, and how a prototype code is generated from the specification. In particular, we study the interface between nondeterminist synchronous prototypes and determinist asynchronous software libraries. We take into account, problems related with nonreversibility of actions and the transactional semantics of the specification language that is kept in the prototypes. A convenient delayed execution mechanism is proposed for the library linking part of the generated code.     

A High-level Microprocessor Power Modeling Technique Based on Event Signatures

This paper presents a technique for high-level power estimation of microprocessors. The technique, which is based on abstract execution profiles called ‘event signatures’, operates at a higher level of abstraction than commonly-used instruction-set simulator (ISS) based power estimation methods and should thus be capable of achieving good evaluation performance. As a consequence, the technique can be very useful in the context of early system-level design space exploration. In this paper, we also compare our power estimation results to those from the instruction-level simulators Wattch and Sim-Panalyzer. In these experiments, we demonstrate that with a good underlying power model, the signature-based power modeling technique can yield accurate estimations (a mean error of 3.1% compared to Wattch in our experiments). At the same time, our signature-based power modeling technique is at least an order of magnitude faster than the simulations performed by Wattch or Sim-Panalyzer.     

A computer-aided protocol design by production systems approach

A computer-aided protocol design system based on the OPS5 production system approach is proposed. Communication rules (state transitions) are specified as triples of object-attribute-value and the modeling of state transitions is specified by production rules. An incremental validation algorithm to facilitate protocol design is also presented. Based on a globally shared dataspace (working memory) in which different types and levels of information are all represented in a uniform structure, the OPS5 production system integrates both rule-based and procedure-based computations. Using this characteristic, the machine-dependent part can be abstractly specified through external procedure calls, the details of which can be coded in a procedure language until the implementation phase. Since computations in OPS5 are based on pattern matching, all of the attributes of elements that are in production rules or in external procedure calls can act as data templates for generic data types. This capability enhances the generic specification that allows different realizations for various implementation environments     

A Real-Time Scheduler Design for a Class of Embedded Systems

We consider here the design aspect of a real-time scheduler for a class of embedded systems. For this purpose, we design a feedback controller for a reservation-based CPU scheduler for soft real-time systems. The execution time of soft real-time systems, such as multimedia systems, portable MP3 players, personal digital assistants, cellular phones, and embedded Web servers is highly variable. Hence, it is crucial to assign an adequate amount of CPU resources for the running tasks to guarantee the quality of service. On the other hand, it is also important not to allocate the large amount of resources to avoid waste. The purpose of this paper is to attain the aforementioned crucial objectives for a class of embedded systems under real-time computing constraints. Specifically, we provide an analytical model for a real-time scheduler in terms of a switched system with time-varying uncertainty. Moreover, by using Lyapunov stability in a linear matrix inequalities (LMIs) framework, we design a state feedback controller that stabilizes the switched system. This, in fact, achieves the regulation of scheduling errors caused by time-varying uncertainty to a desired level. We extend an LMI-framework-based control scheme to a relatively new control application domain, i.e., a soft realtime scheduling domain. We provide performance analysis under scheduler simulation environments and implement a feedback bandwidth server scheduler under a real-time kernel simulator. In the simulation studies, the advantages of the controller design scheme are clearly highlighted in comparison with some conventional existing open-loop systems.     

Co-synthesis and co-simulation of control-dominated embedded systems

This paper presents a methodology for hardware/software co-design with particular emphasis on the problems related to the concurrent simulation and synthesis of hardware and software parts of the overall system. The proposed approach aims at overcoming the problem of having two separate simulation environments by defining a VHDL-based modeling strategy for software execution, thus enabling the simulation of hardware and software modules within the same VHDL-based CAD framework. The proposed methodology is oriented towards the application field of control-dominated embedded systems implemented onto a single chip.     

Functional Validation of Mixed Hardware/Software Systems based on Specification, Partitioning, and Simulation of Test Cases

Tecs is a test case development methodology for the functional validation of large electronic systems, typically consisting of several custom hardware and software components. The methodology determines a hierarchical top-down test case development process including test case specification, validation, partitioning and implementation. The test case development process addresses the functional validation of the system and its components such as ASICs, boards, HW and software modules; it does not facilitate timing or performance verification. The system functions are used to define test cases at the system level and to derive sub-functions for the system components. Test cases are specified, using a special purpose formalism, and validated before they are applied to the system under test. Furthermore, we propose a technique to partition test cases corresponding to the partitioning of the system into sub-systems and components. This technique can significantly reduce system simulation time because it allows the full validation of system functions by simulation at the sub-system and component level. The system model need only be simulated with a reduced set of stimuli to validate the interfaces between sub-systems. We present a test case specification language and tools that support the proposed methodology. The validation of a switching function illustrates methodology, language, and tools.     

忆感器的Simulink模型及其特性分析

忆感器是一种具有记忆功能的非线性电感器。根据忆感器的数学模型,建立了Simulink仿真模型,并由该模型的仿真结果得到关于忆感器的典型特性,验证了模型的有效性。研究了不同参数对忆感器特性的影响。根据该模型,磁控忆感系统的建模也可以采用类似的方法。     

Use of hybrid models for testing and debugging control software for electromechanical systems

This paper proposes a hybrid modeling language and its application to a simulator-based testing and debugging environment for the control software for electromechanical systems. The new hybrid modeling language is designed mainly focusing on simulation speed, flexibility in connecting with control software, and model reusability. This language maintains the advantages of existing hybrid modeling languages such as Hybrid cc, including the flexibility of constraint programming and the reusability of the object-oriented approach. A new feature of the language is that it allows combination of compositional constraint programming and sequential procedural programming. The compiled code is executed efficiently by the runtime system, which has a built-in mechanism for communicating with external software, eliminating the complicated setup required for integrating the simulator with the control software. Model components programmed by the object-oriented approach allow designers to use existing components and to concentrate on the task of modeling the newly designed hardware. The runtime system has been integrated with a three-dimensional kinematics simulator and a control software design tool to create a simulator-based testing and debugging environment. The effectiveness of this system has been confirmed through its application to real product design projects.     

A Hybrid Simulation Approach for Fast and Accurate Timing Analysis of Multi-Processor Platforms Considering Communication Resources Conflicts

In the early design phase of embedded systems, discrete-event simulation is extensively used to analyse time properties of hardware-software architectures. Improvement of simulation efficiency has become imperative for tackling the ever increasing complexity of multi-processor execution platforms. The fundamental limitation of current discrete-event simulators lies in the time-consuming context switching required in simulation of concurrent processes. In this paper, we present a new simulation approach that reduces the number of events managed by a simulator while preserving timing accuracy of hardware-software architecture models. The proposed simulation approach abstracts the simulated processes by an equivalent executable model which computes the synchronization instants with no involvement of the simulation kernel. To consider concurrent accesses to platform shared resources, a correction technique that adjusts the computed synchronization instants is proposed as well. The proposed simulation approach was experimentally validated with an industrial modeling and simulation framework and we estimated the potential benefits through various case studies. Compared to traditional lock-step simulation approaches, the proposed approach enables significant simulation speed-up with no loss of timing accuracy. A simulation speed-up by a factor of 14.5 was achieved with no loss of timing accuracy through experimentation with a system model made of 20 functions, two processors and shared communication resources. Application of the proposed approach to simulation of a communication receiver model led to a simulation speed-up by a factor of 4 with no loss of timing accuracy. The proposed simulation approach has potential to support automatic generation of efficient system models.     

A Framework for Modeling and Estimating the Energy Dissipation of VLIW-Based Embedded Systems

This paper describes a technique for modeling and estimating the power consumptionat the system-level for embedded VLIW (Very Long Instruction Word) architectures.The method is based on a hierarchy of dynamic power estimationengines: from the instruction-level down to the gate/transistor-level. Powermacro-models have been developed for the main components of the system: theVLIW core, the register file, the instruction and data caches. The main goalis to define a system-level simulation framework for the dynamic profilingof the power behavior during the software execution, providing also a break-downof the power contributions due to the single components of the system. Theproposed approach has been applied to the Lx family of scalable embedded VLIWprocessors, jointly designed by STMicroelectronics and HPLabs. Experimentalresults, carried out over a set of benchmarks for embedded multimedia applications,have demonstrated an average accuracy of 5% of the instruction-level estimationengine with respect to the RTL engine, with an average speed-up of four ordersof magnitude.     

基于Simulink的液压动力系统动态仿真

介绍了Simulink软件包的特点，并利用功率键合图建立了液压动力系统的动态模型，应用Simulink进行了仿真，对其动态响应做了分析，结果表明Simulink是液压系统仿真的一条有效途径，他为液压控制系统的设计及分析提供了有价值的参考。     

基于领域工程的特种作战指挥系统建模研究

在领域工程理论的指导下,通过分析研究特种作战自动化指挥领域各业务领域的特点,采用面向特征的领域分析方法,结合面向对象的软件设计思想,得出了该领域的可继承和研究的共用和业务通用构件及系统集成模型框架。阐述了特种作战自动化指挥领域分析模型、领域设计模型和领域实现模型的建模过程及各阶段建模目标,介绍了选用的建模工具及模型的表示方法。