Modellbasierte Diagnose — Überblick und technische Anwendung

Model-based diagnosis deals with a set of methods for finding faults in (usually technical) systems by examining the way these systems operate when functioning correctly, instead of using the classical “expert system” approach of painstakingly collecting all individual fault cases. The types of components occurring in a problem domain have their behavior described in a generic catalogue and can then be simply combined to describe any system from that domain. If faulty behavior is observed, a general solution algorithm can be applied to identify the set of components whose misbehavior explains the fault.     

2006 Best Paper Award

The IEEE Transactions on Semiconductor Manufacturing awarded the 2006 Best Paper Award to T. Pfingsten and D.J.L. Herrmann for their paper, "Model-based design analysis and yield optmization."     

Turbo and Turbo-Like Codes: Principles and Applications in Telecommunications

For decades, the de facto standard for forward error correction was a convolutional code decoded with the Viterbi algorithm, often concatenated with another code (e.g., a Reed-Solomon code). But since the introduction of turbo codes in 1993, much more powerful codes referred to collectively as turbo and turbo-like codes have eclipsed classical methods. These powerful error-correcting techniques achieve excellent error-rate performance that can closely approach Shannon's channel capacity limit. The lure of these large coding gains has resulted in their incorporation into a widening array of telecommunications standards and systems. This paper will briefly characterize turbo and turbo-like codes, examine their implications for physical layer system design, and discuss standards and systems where they are being used. The emphasis will be on telecommunications applications, particularly wireless, though others are mentioned. Some thoughts on the use of turbo and turbo-like codes in the future will also be given.     

Modeling and Simulation in Support of System Level Design for High Acceleration Linear Motors

Software tools offer powerful support in the areas of engineering specification, design, implementation, and test. The tools are at their most potent when they actively promote agility and responsiveness throughout a product life cycle and leave a legacy of knowledge to inform future product development. Model-based design facilitates these benefits by considering a simulation of the system under development as an executable specification. This executable specification may be regarded as “one truth” across engineering teams with the simulation being abstracted or enhanced as appropriate. First-principle, data-driven, and physical modeling further strengthens model-based design, by allowing the agility and responsiveness afforded by model-based design to be relevant for both algorithmic and nonalgorithmic design considerations. Indeed, models are a powerful means to offer support for in-service operation, diagnostics of unintended operations and assessment and upgrades of control systems and/or system architectures during the entire life-cycle of a product. This paper will consider the benefits of physical modeling and model-based design through an example of a high acceleration linear motor. The motor type, power electronic-drive switching strategy, and power-electronic drive architecture will be considered. Finally, the use of parallel computing within the context of this application will be discussed, in particular as an effective means to generate results for a large number of operational scenarios in a time-effective manner.      

Induction Machine Condition Monitoring Using Neural Network Modeling

Condition monitoring is desirable for increasing machinery availability, reducing consequential damage, and improving operational efficiency. Model-based methods are efficient monitoring systems for providing warning and predicting certain faults at early stages. However, the conventional methods must work with explicit motor models, and cannot be applied effectively for vibration signal diagnosis due to their nonadaptation and the random nature of vibration signal. In this paper, an analytical redundancy method using neural network modeling of the induction motor in vibration spectra is proposed for machine fault detection and diagnosis. The short-time Fourier transform is used to process the quasi-steady vibration signals to continuous spectra for the neural network model training. The faults are detected from changes in the expectation of vibration spectra modeling error. The effectiveness of the proposed method is demonstrated through experimental results, and it is shown that a robust and automatic induction machine condition monitoring system has been produced     

The use of public key cryptography in communication system design

Since the time of Caesar, cryptography has been used in the design of secure communications systems. Recently, Diffie and Hellman [2] have introduced a new type of cryptographic method, based on "trapdoor" functions, which promises to be of great value in the design of such systems. We present a review of public key cryptosystems, followed by examples of communications systems which make particularly elegant use of their properties.     

Speed-up trend analysis for H.261 and model-based image coding algorithms using a parallel-pipeline model

Model-based and object-oriented coding algorithms are generally more computationally complex than current block-based image coding standards such as H.261, due primarily to the complexity of the image analysis they require. In this paper, simulations of H.261 and two model-based coding algorithms are analysed in terms of their computational complexity, and mapped onto a generalised image coder parallel-pipeline model. Example implementations of the H.261 coder and an object-oriented coder using general purpose parallel processor systems are then presented to confirm the validity of the performance trend analyses; these achieve maximum speedups of about 11 and 1.7, respectively, using up to 16 processors. The performance trends shown by the analysis indicate that the complexity of model-based coding algorithms, when combined with their reliance on coding picture differences and content-dependent algorithm execution times, interact to make it very difficult to achieve significant speed-up of sequential algorithms. Furthermore, the algorithm complexity and abstract data structures will make direct hardware implementations increasingly difficult. Overcoming these problems to achieve real-time model-based coders may require significant algorithmic compromises to be made.     

Checking the play in plug-and-play

It's surprising to realize that buyers of intellectual property (IP) blocks used in system-on-chip (SOC) designs may not be entirely aware of what they're getting and how it works. But that's one reason why software for IC design verification is gaining attention: to ensure that those blocks will work as intended, both internally and with other components. Another reason is time to market. SOC providers could shorten their time to market considerably if they didn't have to spend up to 70 percent of it verifying that their designs will plug and play. SOCs are complex designs that fit most or all of the circuitry required for a cellphone, for instance, or a Bluetooth radio on a single IC. As their numbers and complexity increase, the design verification gap is widening. But help is at hand in a new type of design verification called assertions-based verification, although a looming standards battle threatens to slow its widespread adoption.     

Automotive electronics power up

People are spending increasing amounts of time in their cars. As a result, automakers are equipping vehicles with more and more power-draining creature comforts as selling points. Cup holders have given way to navigational systems, separate driver and passenger climate controls, and surround sound and compact disk players. But performance and handling improvements under the hood, such as dynamic stability controls, electronic suspensions, and precision-controlled fuel injection, also need power from the 14-V system featured in today's cars. To handle the situation, automotive manufacturers and suppliers are embracing a 42-V standard for system voltage as they design new products. The challenge for designers, however, is that the cost of the new electronics cannot prohibit the economic production of automobiles. This hurdle must be cleared before cars with 42-V systems will become available to consumers. The paper discusses why 42 Volts was chosen, how many batteries will be needed, control systems, start/stop operation, and the influence of silicon devices on cost     

Photovoltaics in an architectural context

In well‐populated areas, such as western Europe, PV is often integrated into the building envelope. Despite the fact that there are many examples showing that PV can be an aesthetically neutral or visually attractive element in architecture, many BIPV systems display few architectural qualities. But if well applied, PV can increase a building's character and value. Within Task 7 of the IEA PVPS programme a team of experts with an architectural background studied which key requirements needed to be complied with (design criteria for good‐quality PV projects) in order to produce successful PV integration. These criteria are discussed in the article. PV is not automatically considered an indispensable material in architectural terms. This is why, no matter how well it is integrated, PV remains an ‘added’ element. Architects can take this as their starting point and can use one of the design approaches that are presented in the article. These criteria for incorporating PV in the building design and the design criteria for good‐quality PV projects are important to architects and architectural critics in determining why a BIPV project, be it their own design or that of a colleague, is or is not aesthetically pleasing. This offers learning opportunities and reasons for follow‐up or improvement options. Architects who apply PV in a well‐thought‐out way can make their clients very happy, and thereby contribute to a greater acceptance of PV technology. Copyright © 2004 John Wiley & Sons, Ltd.     

车载电源总线的电磁兼容性设计

在车载通信系统中,总线的种类繁多,类型多样。而对于车内的任何一台设备,都必须有电源才能工作。因此电源总线在车载通信系统中的作用非常重要,但在实际的设计中,电源总线的电磁兼容设计很容易被设计者所忽视。基于以上原因,本文从车载总线中电源线的信号传输特征角度对车载总线进行了简要的分析,并根据分析结果对电源总线的传导发射进行了测试,得出了采用双绞线作为电源总线有利于信号传输的结论。这一结论对于工程实践有着重要的指导意义。     

Virtual prototyping of embedded control software in mechatronic systems: A case study

The large majority of technological devices can be seen as the sum of components of heterogeneous nature (electrical, mechanical, thermal, software, etc.) so that their analysis and design calls for the use of tools from different engineering disciplines. Integration among the different tools is particularly relevant at control system design level, since it is at this stage that it is required to analyze the behavior of both each single component and the system as a whole, with different levels of detail. In this paper mechatronic systems are considered, that exhibit a strong interplay between mechanical and electrical components, and the issue of modeling and designing embedded control algorithms and architectures for such systems is addressed. In particular, an integrated virtual prototyping approach for analyzing the system behavior down to embedded software level is proposed, that can be used in a wide number of situations that can represent the actual real-world operational conditions of consumer products. This approach can be used for system design (in particular at control systems level), embedded software design, and virtual testing so as to optimize and reduce the costs of late stage software development, physical prototypes, and their testing. The case study is based on some recently derived software tools that perform the co-simulation of the firmware execution and the multi-physical controlled system dynamics. The actual control software implemented in the final product can be entirely developed and tested inside the virtual prototype. To prove the validity and potentialities of the proposed approach, a real case study is presented, regarding a very common, though complex to simulate, mechatronic system such as an electric sliding gate. It turns out that the proposed environment goes beyond hardware-in-the-loop tools, since it does not require the use of specific hardware (the hardware itself is simulated in detail) but allows to analyze in detail the status of the microprocessors and peripherals at arbitrary time-scales and allows the designer to study at the earliest design stages the dynamics between the multi-physical controlled system and the firmware, without committing to a given hardware structure.     

直放站在移动通信网中存在的问题及对策

直放站作为移动通信基站系统的有效补充,可以经济、迅速、有效地填补盲区,改善网络质量,带来可观的经济效益,在网络中得到广泛的应用。但是由于CDMA网络自身的特性,CDMA直放站在使用过程中,会出现各种各样的问题。就CDMA直放站在应用过程中存在选址不当造成掉话率高、直放站质量原因引起的问题、直放站设计不当引发问题等提出相应的解决办法。     

A hybrid system for two-dimensional image recognition

In this paper, after briefly considering the reasons that prevented the development of hybrid systems for signal processing (SP), we point out the requirements for their future exploitation. The need for a better knowledge of different approaches in the scientific community and the definition of methodologies for designing hybrid systems are highlighted as two key points. Then we suggest that the well-known “task-structure analysis” design technique should be modified to make it suitable for hybrid systems. The proposed modification is based on the main need to choose the roles of different approaches and the mechanisms to integrate them. As an example we describe the design of a hybrid system for two-dimensional (2-D) image recognition; the system is based on the integration of a numerical, a symbolic, and a connectionist approach. We detail the integration of the symbolic and connectionist approaches to the generation of the models of the objects to be recognized. We describe the main problems involved and the solutions adopted. In particularly, we exploit the synergistic aspects of the two approaches in order to overcome the bottleneck of knowledge acquisition. Finally, we report experimental results on two applications to show some advantages of the proposed hybrid system     

Heading off emergencies in large electric grids

Until recently, power systems in the United States could be counted on to operate reliably. For more than half a century, generating and transmission reserves were ample enough to absorb constant increases in the consumption of electricity. But in recent years, that growth has combined with two other trends-larger than ever bulk transfers of electricity over ever wider areas-to subject power systems to operating conditions unanticipated during their original design. Here, the authors describe how the blackouts that swept power systems in the Western USA in 1996 could have been prevented by the use of a centralized automatic response system.     

Communication architecture for cooperative systems in europe - [Automotive networking series]

Wireless communications for intelligent transportation systems promise to be a key technology for avoiding the traffic nightmares of today - accidents and traffic jams. But there is one major challenge to be overcome before such a cooperative system can be put into place: standardization. This article provides an overview of the technical developments in Europe and their convergence toward a set of European standards. We address the current state of the standardization activities and the potential scenarios and use cases, and we describe the fundamental concepts of a European communication architecture for cooperative systems.     

基于广义Gabor变换的最优LOFDM系统的脉冲成形

LOFDM(Lattice Orthogonal Frequency Division Multiplexing )是时频弥散信道上的一种高速数据传输技术。但当LOFDM系统的脉冲成形滤波器不具有最优的时频局域化特性时,必将引入严重的ISI和/或ICI。因此脉冲成形滤波器的设计是最优LOFDM系统设计的重要组成部分。Strohmer和Beav(2001,2003)给出了一种LOFDM脉冲成形滤波器的设计方法,但是计算量较大。为此,该文提出了一种广义Gabor变换,通过构造广义紧致Gabor原子来完成最佳LOFDM脉冲成形滤波器的设计的数值实现。理论分析和仿真试验都证明该方法比Strohmer和Beaver给出的方法更简单有效。     

The design space of wireless sensor networks

In the recent past, wireless sensor networks have found their way into a wide variety of applications and systems with vastly varying requirements and characteristics. As a consequence, it is becoming increasingly difficult to discuss typical requirements regarding hardware issues and software support. This is particularly problematic in a multidisciplinary research area such as wireless sensor networks, where close collaboration between users, application domain experts, hardware designers, and software developers is needed to implement efficient systems. In this article we discuss the consequences of this fact with regard to the design space of wireless sensor networks by considering its various dimensions. We justify our view by demonstrating that specific existing applications occupy different points in the design space.     

An overview of today’s high-level synthesis tools

High-level synthesis (HLS) is an increasingly popular approach in electronic design automation (EDA) that raises the abstraction level for designing digital circuits. With the increasing complexity of embedded systems, these tools are particularly relevant in embedded systems design. In this paper, we present our evaluation of a broad selection of recent HLS tools in terms of capabilities, usability and quality of results. Even though HLS tools are still lacking some maturity, they are constantly improving and the industry is now starting to adopt them into their design flows.     

基于MBSE的微波统一测控系统测试性设计

针对当前微波统一测控系统研制中存在的测试性要求宽松、测试性设计模式落后的问题,通过综合权衡可靠性、维修性和保障性的各项要求和约束条件,确定了微波统一测控系统的测试性定量要求,并对开展测试性定量设计和验证的可行性进行了论证;采用系统工程设计思想,将测试性设计和功能设计融合,构建了基于模型的系统工程（Model-based Systems Engineering,MBSE）的测试性设计环境和设计流程,可为微波统一测控系统在数字化研制过程中开展测试性设计和仿真验证提供参考。