Reactive process control using a blackboard architecture

A software architecture to engineer complex process control applications must combine into the same paradigm efficient reactive and real-time functionalities and mechanisms to capture dynamic time-pressured intelligent behaviors, and must provide convenient high level tools to free the programmer from having to think at an unappropriate level of detail. We implement such characteristics into a blackboard framework that builds the basic abstract elements of reactive behavior and the blackboard computational model on top of low level real-time operating system functions. Under this approach, the engineer gets a powerful and flexible high level medium to map a complex system design that requires artificial intelligence techniques, like intelligent monitoring, and reactive planning and execution, with fully support for real-time programming. The paper also reviews other alternatives which have been explored in the past recent years for implementing complex reactive planning and execution systems.     

Towards runtime discovery, selection and composition of semantic services

Service-orientation is gaining momentum in distributed software applications, mainly because it facilitates interoperability and allows application designers to abstract from underlying implementation technologies. Service composition has been acknowledged as a promising approach to create composite services that are capable of supporting service user needs, possibly by personalising the service delivery through the use of context information or user preferences. In this paper we discuss the challenges of automatic service composition, and present DynamiCoS, which is a novel framework that aims at supporting service composition on-demand and at runtime for the benefit of service end-users. We define the DynamiCoS framework based on a service composition life-cycle. Framework mechanisms are introduced to tackle each of the phases and requirements of this life-cycle. Semantic services are used in our framework to enable reasoning on the service requests issued by end-users, making it possible to automate service discovery, selection and composition. We validate our framework with a prototype that we have built in order to experiment with the mechanisms we have designed. The prototype was evaluated in a testing environment using some use case scenarios. The results of our evaluation give evidences of the feasibility of our approach to support runtime service composition. We also show the benefits of semantic-based frameworks for service composition, particularly for end-users who will be able to have more control on the service composition process.     

A conceptual approach for simulation software

This paper presents concepts and tools for simulation softwares specification. At an abstract level of specification, we define a simulation software as a couple (conceptual structure, abstract machine). The conceptual structure is a structured representation of the simulated system behaviour. The abstract machine is a set of abstract and general mechanisms able to carry out the management of a system defined through its conceptual schema. We focus in the paper on concepts for behaviour structuring and abstract machine tools.     

联邦成员框架代码的自动生成技术研究

联邦成员软件的开发者面临着学习和使用RTI库的问题,大量低层接口的编程往往会使联邦开发者的注意力从联邦问题域转移到RTI技术细节上去.因此生成联邦成员框架代码的设计和实现可以大大降低成员软件开发难度,加快成员软件开发.该文通过分析联邦成员的程序流程和软件组成,采用面向对象的方法对联邦成员进行了抽象,设计了一些体现联邦成员特征的基本类,并基于这些设计实现了一种由HLA对象模型（FOM/SOM）自动生成联邦成员软件框架代码的方法.在RTI和实际的仿真实体模型间提供了一个抽象层,开发者不必考虑联邦成员与RTI之间的信息交换过程,只负责实现仿真实体模型的仿真功能,从而在成员级上实现了成员代码重用.     

Dynamic web service composition based on OWL-S

Composing existing web services for enterprise applications may enable higher level of reuse. However the composition processes are mostly static and lack of support for runtime redesign. In this paper, we describe our approach to the extension of the OWL-S ontology framework for dynamic web service composition. We raise the level of abstraction and propose an abstract service layer so that web services can be com- posed at the abstract service level instead of the concrete level. Each abstract service is attached with an instance pool including all instances of the abstract service to facilitate fail-over and dynamic compositions.     

UM-RTCOM: An analyzable component model for real-time distributed systems

Component-based development is a key technology in the development of software for modern real-time systems. However, standard component models and tools are not suitable for this type of system, since they do not explicitly address real time, memory or cost constraints. This paper presents a new predictable component model for real-time systems (UM-RTCOM) together with a set of tools to support it. The environment allows new components to be developed which can then be assembled to build complete applications, including hardware interaction. The model includes support for real-time analysis at the component and application level. The analysis is achieved by combining component meta-information in the form of an abstract behaviour model and a method to measure worst-case execution times in the final platform. Additionally, we propose an implementation model based on RT-CORBA where the developer uses the UM-RTCOM components and a set of tools to map these elements to elements of the desired platform. In order to apply our proposals, we have used the model and tools in real applications specifically in the context of nuclear power plant simulators.     

High-level management of computation history for the design and implementation of a prolog system

We present the implementation of a Prolog system composed of interpreter and compiler. The originality of our work consists in the adoption of a new framework to realize the main components of the system. The framework relies on new mechanisms, called sleepers. With their help we have developed a complete Prolog interpreter in which all the control activities, from backtracking up to last-call optimization, are performed by the sleeper mechanism. We have also produced a Prolog compiler by using a philosophy and tactics that are completely independent of hardware constraints; it exploits an incremental and abstract implementation technique, based on a delayed non-local execution protocol. Our approach to Prolog system implementation has been extremely useful both in terms of software design and overall performance.     

Exploiting an abstract-machine-based framework in the design of a Java ILP processor

Abstract machines bridge the gap between the high-level of programming languages and the low-level mechanisms of a real machine. The paper proposed a general abstract-machine-based framework (AMBF) to build instruction level parallelism processors using the instruction tagging technique. The constructed processor may accept code written in any (abstract or real) machine instruction set, and produce tagged machine code after data conflicts are resolved. This requires the construction of a tagging unit which emulates the sequential execution of the program using tags rather than actual values. The paper presents a Java ILP processor by using the proposed framework. The Java processor takes advantage of the tagging unit to dynamically translate Java bytecode instructions to RISC-like tag-based instructions to facilitate the use of a general-purpose RISC core and enable the exploitation of instruction level parallelism. We detailed the Java ILP processor architecture and the design issues. Benchmarking of the Java processor using SpecJVM98 and Linpack has shown the overall ILP speedup improvement between 78% and 173%.     

An open-source navigation system for micro aerial vehicles

This paper presents an open-source indoor navigation system for quadrotor micro aerial vehicles (MAVs), implemented in the ROS framework. The system requires a minimal set of sensors including a planar laser range-finder and an inertial measurement unit. We address the issues of autonomous control, state estimation, path-planning, and teleoperation, and provide interfaces that allow the system to seamlessly integrate with existing ROS navigation tools for 2D SLAM and 3D mapping. All components run in real time onboard the MAV, with state estimation and control operating at 1 kHz. A major focus in our work is modularity and abstraction, allowing the system to be both flexible and hardware-independent. All the software and hardware components which we have developed, as well as documentation and test data, are available online.     

Timing analysis of Ada tasking programs

Concurrent real-time software is increasingly used in safety-critical embedded systems. Assuring the quality of such software requires the rigor of formal methods. In order to analyze a program formally, we must first construct a mathematical model of its behavior. In this paper, we consider the problem of constructing such models for concurrent real-time software. In particular, we provide a method for building mathematical models of real-time Ada tasking programs that are accurate enough to verify interesting timing properties, and yet abstract enough to yield a tractable analysis on nontrivial programs. Our approach differs from schedulability analysis in that we do not assume that the software has a highly restricted structure (e.g. a set of periodic tasks). Also, unlike most abstract models of real-time systems, we account for essential properties of real implementations, such as resource constraints and run-time overhead     

An Algebraic Baseline for Automatic Transformations in MDA

Software evolution can be supported at two levels: models and programs. The model-based software development approach allows the application of a more abstract process of software evolution, in accordance with the OMG's MDA initiative. We describe a framework for model management, called MOMENT, that supports automatic formal model transformations in MDA. Our model transformation approach is based on the algebraic specification of models and benefits from mature term rewriting system technology to perform model transformation using rewriting logic. In this paper, we present how we apply this formal transformation mechanism between platformindependent models, such as UML models and relational schemas. Our approach enhances the integration between formal environments and industrial technologies such as .NET technology, and exploits the best features of both.     

SoC芯片设计方法及标准化

随着集成电路技术的迅速发展，集成电路已进入系统级芯片（SoC)设计时代，SoC芯片的集成度越来越高，单芯片上的集成度和操作频率越来越高，投放市场的时间要求越来越短，为了实现这样的SoC芯片，设计越来越依赖IP模块的重用，SoC复杂性的提高和IP模块的多样化，SoC芯片中多个厂商不同IP模块的使用，导致了IP模块可重用的许多问题，IP模块和片上总线，以及EDA工具接口的标准化，是解决IP模块标准化的很好途径，另一方面，SoC芯片设计的复杂性和嵌入软件所占比重的增加，要求更高层次的系统抽象和软硬件的协同设计，使用更流地的设计进行系统的硬件设计和更有效的系统设计方法，描述了SoC芯片设计中的IP模块可重用技术以及所存在的问题，介绍了SoC IP模块和片上总线结构的标准化，讨论了基于C／C＋＋扩展类库的系统级描述语言和基于平台的SoC设计方法。     

Semantic adaptation of multimedia documents

Multimedia documents have to be played on multiple device types. Hence, usage and platform diversity requires document adaptation according to execution contexts, not generally predictable at design time. In an earlier work, a semantic framework for multimedia document adaptation was proposed. In this framework, a multimedia document is interpreted as a set of potential executions corresponding to the author specification. To each target device corresponds a set of possible executions complying with the device constraints. In this context, adapting requires to select an execution that satisfies the target device constraints and which is as close as possible from the initial composition. This theoretical adaptation framework does not specifically consider the main multimedia document dimensions, i.e., temporal, spatial and hypermedia. In this paper, we propose a concrete application of this framework on standard multimedia documents. For that purpose, we first define an abstract structure that captures the spatio-temporal and hypermedia dimensions of multimedia documents, and we develop an adaptation algorithm which transforms in a minimal way such a structure according to device constraints. Then, we show how this can be used for adapting concrete multimedia documents in SMIL through converting the documents in the abstract structure, using the adaptation algorithm, and converting it back in SMIL. This can be used for other document formats without modifying the adaptation algorithm.     

一种面向软件工程的时序逻辑语言

ＸＹＺ系统由时序逻辑语言ＸＹＺ／Ｅ及一组基于该语言的ＣＡＳＥ工具集组成．ＸＹＺ／Ｅ语言的目的是欲使逐步求精，描述及验证、快速原型等一些软件工程方法更加有效．特别地，它还能表示实时通信进程中的动态成分．在统一的框架下，不仅能表示不同层次的抽象描述，而且能表示普通高级语言的各种重要性质．本文是关于这一时序逻辑语言最新、最完整的介绍．     

软件可信评估模型及其工具实现

软件可信评估是软件质量保障的一项重要内容。现有软件可信评估研究存在适用的软件形态单一、评估的可信属性固定、缺乏具体的评估工具等不足。因此,提出了一种通用的软件可信评估模型,系统地讨论了模型的实现过程,开发了一个可信评估管理系统,通过对一个税务领域案例的详细分析,验证了模型实施的可行性。该研究及评估工具能有效辅助软件可信评估活动的实施,指导软件质量的改进。     

基于AADL的软件开发技术研究*

形式化方法对于软件的开发过程有着重要的作用。为了研究体系结构分析与设计语言（AADL）在软件开发中的作用及其技术现状,介绍了AADL的语言组成和相关特性,分析了AADL在软件开发过程中的作用,给出了一个相应AADL工具集的框架模型。在此基础上,对现有的AADL相关工具进行了综述比较,总结出该框架的技术现状,并指出了AADL相关工具开发与应用的趋势。     

Automated fault tolerance augmentation in model-driven engineering for CPS

Cyber-Physical Systems are usually subject to dependability requirements such as safety and reliability constraints. Over the last 50 years, a body of efficient fault-tolerance mechanisms has been devised to handle faults occurring at run-time. However, properly implementing those mechanisms is a time-consuming task that requires a great deal of know-how. In this paper, we propose a general framework which allows system designers to decouple functional and non-functional concerns, and express non-functional properties at design time using domain-specific languages. In the spirit of generative programming, functional models are then automatically “augmented” with dependability mechanisms. Importantly, the real-time behavior of the initial models in terms of sampling times and meeting deadlines is preserved. The practicality of the approach is demonstrated with the automated implementation of one prominent software fault-tolerance pattern, namely N-Version Programming, in the CPAL model-driven engineering workflow.     

A co-modelling method for solving incompatibilities during co-design of mechatronic devices

The design process of mechatronic devices, which involves experts from different disciplines working together, has limited time and resource constraints. These experts normally have their own domain-specific designing methods and tools, which can lead to incompatibilities when one needs to work together using these those methods and tools. Having a proper framework which integrates different design tools is of interest, as such a framework can prevent incompatibilities between parts during the design process. In this paper, we propose our co-modelling methodology and co-simulation tools integration framework, which helps to maintain the domain specific properties of the model components during the co-design process of various mechatronic devices. To avoid expensive rework later in the design phase and even possible system failure, fault modelling and a layered structure with fault-tolerance mechanisms for the controller software are introduced. In the end, a practical mechatronic device is discussed to illustrate the methods and tools which are presented in this paper in details.     

Using Chaos Theory based workload analysis to perform Dynamic Frequency Scaling on MPSoCs

Embedded systems sometimes experience transient overloads due to workload bursts. Such systems have to be designed to take timely reactions at the occurrences of unexpected situations. The development of smart techniques that focus the available computing power on these urgent events and at the same time, slow down the processing frequency during inactive periods could be the key for preserving energy. In the context of this study, we present a Dynamic Frequency Scaling technique based on the workload trend of a dynamic wireless application. The system can adjust the operation frequency by analyzing the workload fluctuations without degrading the final performance or violating any deadlines. In this direction, we employ an abstract model of workload analysis that combines mathematical tools from the Chaos Theory field, allowing the dynamic handling of data streams with complex behavior. To evaluate the efficiency of the proposed approach we applied it using a real application workload on a cycle-accurate Network-on-Chip simulation framework. The simulation results showed that the proposed technique could achieve remarkable improvements at the final power consumption, between 17.5% and 37.8%, depending on the system constraints.