Invisible formal methods for embedded control systems

Embedded control systems typically comprise continuous control laws combined with discrete mode logic. These systems are modeled using a hybrid automaton formalism, which is obtained by combining the discrete transition system formalism with continuous dynamical systems. This paper develops automated analysis techniques for asserting correctness of hybrid system designs. Our approach is based on symbolic representation of the state space of the system using mathematical formulas in an appropriate logic. Such formulas are manipulated using symbolic theorem proving techniques. It is important that formal analysis should be unobtrusive and acceptable to engineering practice. We motivate a methodology called invisible formal methods that provides a graded sequence of formal analysis technologies ranging from extended typechecking, through approximation and abstraction, to model checking and theorem proving. As an instance of invisible formal methods, we describe techniques to check inductive invariants, or extended types, for hybrid systems and compute discrete finite state abstractions automatically to perform reachability set computation. The abstract system is sound with respect to the formal semantics of hybrid automata. We also discuss techniques for performing analysis on nonstandard semantics of hybrid automata. We also briefly discuss the problem of translating models in Simulink/Stateflow language, which is widely used in practice, into the modeling formalisms, like hybrid automata, for which analysis tools are being developed.     

Reliability optimization models for embedded systems with multiple applications

Summary and Conclusions-This paper presents four models for optimizing the reliability of embedded systems considering both software and hardware reliability under cost constraints, and one model to optimize system cost under multiple reliability constraints. Previously, most optimization models have been developed for hardware-only or software-only systems by assuming the hardware, if any, has perfect reliability. In addition, they assume that failures for each hardware or software unit are statistically independent. In other words, none of the existing optimization models were developed for embedded systems (hardware and software) with failure dependencies. For our work, each of our models is suitable for a distinct set of conditions or situations. The first four models maximize reliability while meeting cost constraints, and the fifth model minimizes system cost under multiple reliability constraints. This is the first time that optimization of these kinds of models has been performed on this type of system. We demonstrate and validate our models for an embedded system with multiple applications sharing multiple resources. We use a Simulated Annealing optimization algorithm to demonstrate our system reliability optimization techniques for distributed systems, because of its flexibility for various problem types with various constraints. It is efficient, and provides satisfactory optimization results while meeting difficult-to-satisfy constraints.     

Regularization and validation of neural network models of nonlinear systems

A characteristic feature of the neural network models is the large number of parameters. A model offering many parameters usually gives rise to problems, and the variance contribution to the modeling error might be very high. Therefore, it is crucial to find the model with the optimal number of parameters. In this paper two techniques of selection of the optimal number of model parameters are described and compared: explicit and implicit regularization techniques. Model validation forms the final stage of an identification procedure with the aim of assessing objectively whether the identified model agrees sufficiently well with the observed data. In this paper the reliability of the correlation-based validation tests and the χ²-test is analyzed.     

基于GPS定位的嵌入式汽车监控器设计

随着人们生活水平的提高,汽车逐渐进入了普通家庭,中国各大城市的汽车保有量逐年增加.同时,汽车被盗、被抢也成为一个较为严重的社会问题.虽然各类汽车防盗/报警器在汽车上的应用在一定程度上解决了汽车的安全问题,但随着盗贼手段的提高,大多的报警器容易迅速被破坏.汽车报警的方式多为灯光闪烁和喇叭鸣响,车主不一定能得到报警,周边的居民却被严重干扰.此外,盗贼破坏报警器,盗走汽车后,外观稍加改动,汽车就如石沉大海,无法追踪了.为了解决这些问题,本设计利用GPS监控的方式跟踪汽车位置,在被盗情况下可利用GSM短信模块随时向车主或公安部门发送汽车的GPS定位,加快破案速度.     

Understanding Internet topology: principles, models, and validation

Building on a recent effort that combines a first-principles approach to modeling router-level connectivity with a more pragmatic use of statistics and graph theory, we show in this paper that for the Internet, an improved understanding of its physical infrastructure is possible by viewing the physical connectivity as an annotated graph that delivers raw connectivity and bandwidth to the upper layers in the TCP/IP protocol stack, subject to practical constraints (e.g., router technology) and economic considerations (e.g., link costs). More importantly, by relying on data from Abilene, a Tier-1 ISP, and the Rocketfuel project, we provide empirical evidence in support of the proposed approach and its consistency with networking reality. To illustrate its utility, we: 1) show that our approach provides insight into the origin of high variability in measured or inferred router-level maps; 2) demonstrate that it easily accommodates the incorporation of additional objectives of network design (e.g., robustness to router failure); and 3) discuss how it complements ongoing community efforts to reverse-engineer the Internet.     

基于嵌入式的数据采集系统设计

随着微电子技术和计算机技术的发展,微处理器芯片的功能越来越强大,嵌入式技术也越来越受到人们的关注,文中设计了基于ARM处理器和嵌入式LINUX的数据采集系统.设计了基于STM32F103VBT6的数据采集系统,分析了系统总体架构及其子电路模块、外围电路.     

构筑嵌入式系统的安全屏障

5年前,数十亿嵌入式系统成为了注意的焦点,当时权威人士预测Y2K故障将会扰乱制造、配电、运输、通信、水净化、现金提取、武器系统的正常运作,还将带来其他许多灾难.全球的政府和私营公司花费数千工时和数十亿美元来分析和更新嵌入式固件,以便能避免可能发生的灾难.这些嵌入式设备目前面临新的敌人,来自越来越多的黑客和恐怖分子,他们试图造成类似的危害,强制进行计划外的运作,或提取保密信息.对于任何新的嵌入式系统设计来说,这个新的现实使安全问题成为最优先考虑的事项.     

RF packaging and passives: design, fabrication, measurement, and validation of package embedded inductors

Design, modeling, and characterization of inductors embedded in a package substrate promising higher quality factor (Q) and lower cost than on-chip inductors is described. In addition to the problem of large conductor losses, on-die inductors with or without magnetic materials consume considerable die area and require the removal of the first-level interconnect bumps beneath them to maintain a reasonably high Q value. Moving inductors to the package eliminates the need for bump array depopulation and, thus, mitigates the potential reliability problems caused by voids in the epoxy underfill between the die and the substrate. Competency developed to design, fabricate, and characterize inductors based on standard organic flip-chip packaging technology is described. Physical design details along with measurement procedures and results are discussed. In addition, modeling techniques for achieving good correlation to measured data are included.     

A unified approach to characterization of PWM and quasi-PWMswitching converters: topological constraints, classification, andsynthesis

Topological constraints are obtained for pulse width-modulation (PWM) (under both continuous and discontinuous current modes) and quasi-PWM (including families of quasi-resonant and quasi-square wave) converters by identifying their three structures. Switching sequences of these converters and a classification of quasi-PWM power converters are presented. A dual circuit of an ideal diode and an ideal switch are proposed and used to obtain duals of the switching converters in one step. A procedure for the synthesis of quasi-PWM converters is presented     

Design of multivariable control systems using reduced-order models

In designing multivariable control systems using reduced-order models it is shown that, provided certain properties are satisfied, the original model is closed-loop stable if the reduced model is likewise stable. The reduction procedure given is new and the design uses the inverse Nyquist array method.     

用例模型的Z语言形式化描述方法

以UML用例模型为主要研究对象,通过对UML用例模型概念和Z抽象符号的分析,采用Z形式化语言对用例模型建模元素的抽象语法和语义进行形式化的描述,提出了用例模型到Z形式语言的映射规约,并建立了UML用例模型图到Z形式规约的映射与转换机制。     

Cooperative problem solving in human-machine systems: theory,models, and intelligent associate systems

In complex problem solving domains such as supervisory control, one approach to human-centered automation is intelligent associate systems. This paper proposes a taxonomy of cooperative problem solving; provides an analysis of models used in cooperative problem solving; and discusses a variety of intelligent associate systems     

系统体系方法与软件系统功能形式分解

从系统体系理论和方法出发,研究基于物联网、云计算的开放应用软件系统功能分解的描述和评价方法,提出用功能框架方法对系统从抽象到具体进行描述对于系统体系的重要性.提出从抽象出发的适应软件系统体系建立的功能分解方法和功能评估方法,并说明这些方法在系统开发以及建立系统稳定中间形式中的作用,这有助于在物联网、云计算和SOA等开放环境下的大型应用软件系统的建设、部署和维护过程的改进.     

Energy-efficient design of battery-powered embedded systems

Energy-efficient design of battery-powered systems demands optimizations in both hardware and software. We present a modular approach for enhancing instruction level simulators with cycle-accurate simulation of energy dissipation in embedded systems. Our methodology has tightly coupled component models thus making our approach more accurate. Performance and energy computed by our simulator are within a 5% tolerance of hardware measurements on the SmartBadge. We show how the simulation methodology can be used for hardware design exploration aimed at enhancing the SmartBadge with real-time MPEG video feature. In addition, we present a profiler that relates energy consumption to the source code. Using the profiler we can quickly and easily redesign the MP3 audio decoder software to run in real time on the SmartBadge with low energy consumption. Performance increase of 92% and energy consumption decrease of 77% over the original executable specification have been achieved     

Verification and validation of simulation models

This publication contains reprint articles for which IEEE does not hold copyright. You may purchase this article from the Ask*IEEE Document Delivery Service at http://www.ieee.org/services/askieee/.     

SHIM: a deterministic model for heterogeneous embedded systems

Typical embedded hardware/software systems are implemented using a combination of C and an HDL such as Verilog. While each is well-behaved in isolation, combining the two gives a nondeterministic model of computation whose ultimate behavior must be validated through expensive (cycle-accurate) simulation. We propose an alternative for describing such systems. Our software/hardware integration medium (shim) model, effectively Kahn networks with rendezvous communication, provides deterministic concurrency. We present the Tiny-shim language for such systems and its semantics, demonstrate how to implement it in hardware and software, and discuss how it can be used to model a real-world system. By providing a powerful, deterministic formalism for expressing systems, designing systems, and verifying their correctness will become easier.     

The Cesame project: formal design of high speed multimedia cooperative systems

The project Cesame, a collaborativeCnet andCnrs project, aims to develop an adequate methodology, supported by formal techniques and tools, for designing and implementing high speed multimedia cooperative systems. This paper, the first of this special issue of the Annals of Telecommunications, dedicated to Cesame, presents its main purposes and significant results. The rationale of the project is given first. From its global objectives, the set of studies that are under development are presented and the main results, a subset of which only appears in this issue, are summarised. Directions of ongoing work are also given.     

ASE and receiver induced noise penalty: Analytical models and experimental validation in NRZ/RZ systems

We present an analytical model to account for amplified spontaneous emission (ASE) noise in long-haul systems. Our approach provides a drastic speed-up of system budgeting compared to conventional modeling based on split-step methods. We have validated the analytical model experimentally and numerically. We also are reporting on a new analytical model to account for electrical filter-induced noise penalty and show that this model agrees well with fully numerical simulations.     

Testing embedded memories in telecommunication systems

Extensive system testing is mandatory nowadays to achieve high product quality. Telecommunication systems are particularly sensitive to such a requirement; to maintain market competitiveness, manufacturers need to combine reduced costs, shorter life cycles, advanced technologies, and high quality. Moreover, strict reliability constraints usually impose very low fault latencies and a high degree of fault detection for both permanent and transient faults. This article analyzes major problems related to testing complex telecommunication systems, with particular emphasis on their memory modules, often so critical from the reliability point of view. In particular, advanced BIST-based solutions are analyzed, and two significant industrial case studies presented     

Participant registration, validation, and key distribution forlarge-scale conferencing systems

DiRK (Distributed Registration and Key distribution) is a technique that can be used in large-scale conferencing systems to handle participant registration, validation, and key distribution in a decentralized and distributed way. The basic idea is to distinguish active and passive participants in a conference session, and to have the active participants assist the session holder to register participants and distribute session keys accordingly. This article introduces the basic principles of DiRK and overviews a prototype implementation for the Internet Multicast Backbone (MBone). As an exemplary application, the article also addresses the use of DiRK in distance education and teleteaching