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Annual IEEE International systems Conference

作者： Christoph Lauer Reinhard German Jens Pollmer Department of Computer Science 7 Computer Networks and Communication Systems University of Erlangen-Nuremberg Department of Safety Electronics Audi AG Ingolstadt

ISBN: (纸本)9781424458820

Designing integrated electronic control units (ECU) in the automotive domain is challenging especially when legacy sub-systems are involved. Nevertheless, important design decisions have to be made at early design stages when some performance parameters of new sub-systems may not be validated yet. To account for uncertainty in the system development we use statistical modeling and discrete event simulation to perform sensitivity analysis from an average-case perspective. Average-case analysis is useful if performance aspects during normal system operation are of interest. The simulation model we implemented enables us to conduct holistic sensitivity analyses of systems consisting of multiple controllers, field-busses, sensors, actors, and applications. Applications are modeled as signal chains traversing the system model experiencing delay in each node along the predefined path. We present the strength of our approach by analyzing the latency of a distributed application in case of an asynchronous, synchronous, and event-triggered integrated ECU context. The results show that clock drift may result in high signal latencies in asynchronous ECUs and synchronous ECUs are superior in terms of signal latency and jitter. Event-triggered ECUs have to be designed carefully and come with trade-offs between performance of the legacy system and new applications.

关键词： Discrete event simulation Timing Automotive engineering Embedded system Delay Sensitivity analysis Uncertainty Performance analysis Analytical models Sensor systems and applications

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NETWORKING 2010: 9th International IFIP TC 6 Networking Conference Chennai, India, May 11-15, 2010 Proceedings 9

NETWORKING 2010: 9th International IFIP TC 6 Networking Conf...

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9th International IFIP TC 6 Networking Conference, NETWORKING 2010

作者： Crovella, Mark Feeney, Laura Marie Rubenstein, Dan Raghavan, S.V. Boston University Department of Computer Science 111 Cummington St. BostonMA United States Swedish Institute of Computer Science Communication Networks and Systems Laboratory Box 1263 Kista Sweden Columbia University 450 Computer Science Bldg. MC 0401 1214 Amsterdam Ave NewYorkNY United States Indian Institute of Technology Madras Department of Computer Science and Engineering Chennai India

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MPSK modulation by optical injection locked VCSEL

MPSK modulation by optical injection locked VCSEL

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Conference on Lasers and Electro-Optics

作者： Guo, Peng Yang, Weijian Parekh, Devang Hong, Cheng Zhang, Cheng Chen, Zhangyuan Chang-Hasnain, Connie J. Department of Electrical Engineering and Computer Sciences University of California Berkeley CA 94720 United States State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science United States Peking University Beijing 100871 China

Optical phase modulator based on OIL-VCSEL is investigated for the first time. Simulation shows a directly modulated OIL-VCSEL can function as a key component in QPSK or 8PSK transmitters. Preliminary phase-shift-keyi... 详细信息

ISBN: (纸本)9781557528902

关键词： Optical signal processing

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Schedulability Analysis in Time-Triggered Automotive Real-Time systems

Schedulability Analysis in Time-Triggered Automotive Real-Ti...

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IEEE Conference on Vehicular Technology (VTC)

作者： Christoph Lauer Kai-Steffen Hielscher Reinhard German Jens Pollmer Department of Computer Science 7 Computer Networks and Communication Systems University of Erlangen Nuremberg Germany Department of Safety Electronics AUDI AG Ingolstadt Germany

In embedded automotive real-time systems correct timing is required to effectively implement distributed applications, time-triggered communication, and integration of intelligent safety applications. We use formal schedulability analysis to validate the task timing for asynchronous real-time systems in an automotive context. Restricting the computational model to purely time-triggered task activation and applying application specific constraints enables us to perform exact response time analyses without pessimism. The analysis can be done efficiently since our computational model drastically limits the number of critical instant candidates to be considered for the worst-case scenario. Simulation results show that the original computational model incorporates a significant amount of response time overestimation and a high computational workload. The presented method can be applied in early design stages as well as in series development and helps to reduce development risks for electronic control units and embedded telematic systems.

关键词： Computational modeling Real time systems Context Time factors Automotive engineering Analytical models Clocks

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Experimental measurement of growth patterns on fossil corals:Secular variation in ancient Earth-Sun distances

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Chinese science Bulletin 2010年第35期55卷 4010-4017页

作者： ZHANG WeiJia1,3,4,LI ZhengBin2,3 & LEI Yang1 1 Department of Physics,Peking University,Beijing 100871,China 2 Department of Electrical Engineering and computer science,Peking University,Beijing 100871,China 3 State Key Laboratory of Advanced Optical communication systems & networks,Peking University,Beijing 100871,China 4 Committee of Yuanpei Honors Program,Peking University,Beijing 100871,China Department of Physics Peking University Beijing 100871 China State Key Laboratory of Advanced Optical Communication Systems & Networks Peking University Beijing 100871 China Committee of Yuanpei Honors Program Peking University Beijing 100871 China Department of Electrical Engineering and Computer Science Peking University Beijing 100871 China

In recent years,much attention has been given to the increase in the Earth-Sun distance,with the modern rate reported as 5-15 m/cy on the basis of astronomical ***,traditional methods cannot measure the ancient leaving rates,so a myriad of research attempting to provide explanations were met with unmatched *** this paper we consider that the growth patterns on fossils could reflect the ancient Earth-Sun *** mechanical analysis of both the Earth-Sun and Earth-Moon systems,these patterns confirmed an increase in the Earth-Sun *** a large number of well-preserved specimens and new technology available,both the modern and ancient leaving rates could be measured with high precision,and it was found that the Earth has been leaving the Sun over the past 0.53 billion *** Earth's semi-major axis was 146 million kilometers at the beginning of the Phanerozoic Eon,equating to 97.6% of its current *** modern leaving rates are 5-14 m/cy,whereas the ancient rates were much *** results indicate a special expansion with an average expansion coefficient of 0.57H0 and deceleration in the form of Hubble *** the basis of experimental results,the Earth's semi-major axis could be represented by a simple formula that matches fossil measurements.

关键词：地球太阳古代距离生长模式实验石珊瑚量化

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Modeling and Analysis of Advanced Automotive ECU Architectures at Early Design Stages Using EMF and Model Transformation

Modeling and Analysis of Advanced Automotive ECU Architectur...

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International Conference on Secure Software Integration and Reliability Improvement Companion (SSIRI-C)

作者： Christoph Lauer Reinhard German Jens Pollmer Department of Computer Science 7 Computer Networks and Communication Systems University of Erlangen Nuremberg Germany Safety Electronics I/EK-541 Audi AG Ingolstadt Germany

In the automotive industry active safety functions are deployed to better protect the passengers and vulnerable road users in case of an accident. To do so, advanced system architectures which enable an OEM to integrate this new functionality safely and efficiently have to be developed. In order to evaluate different possible concepts at an early stage in the development, model-based approaches are feasible. We propose a methodical approach to evaluate architecture concepts with regard to standard analysis methods as well as application specific evaluation techniques. We use UML to define the meta-model structure of the system architecture, model the instances of the meta-model using EMF and a generated graphical editor, and perform evaluation operations with the help of an MDE framework. The tool chain allows for an easy modeling of system models at early design stages and performing application specific analysis techniques. To validate the feasibility of the approach we apply real-time schedule simulation to two example models.

关键词： Automotive engineering Road safety Industrial accidents Protection Road accidents Unified modeling language Performance evaluation Model driven engineering Performance analysis Job shop scheduling

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Performance Evaluation of Network Mobility Handover over Future Aeronautical Data Link

Performance Evaluation of Network Mobility Handover over Fut...

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2010 IEEE Global Telecommunications Conference GLOBECOM 2010

作者： Serkan Ayaz Felix Hoffmann Christoph Sommer Reinhard German Falko Dressler Institute of Communications and Navigation German AeroSpace Center Wessling Germany Computer Networks and Communication Systems Department of Computer Science University of Erlangen Germany

The aviation community is currently working on the standardization of data communication systems for the future air traffic management. In this context, the ICAO and EUROCONTROL are working on the standardization of IP-based aeronautical telecommunications network and future radio access technologies, respectively. With this work, for the first time, we integrate L-DACS 1, which is one candidate for future radio access technologies, with realistic IP-based network layer functionality and analyze the handover delay performance. We first investigate the effect of link layer retransmissions on handover delay performance. We realized that for regions with low signal-to-noise ratio (BER of 1e-3), link layer retransmissions improve the total handover delay (layer 2 and 3) by about 80%. Considering regions with high signal-to-noise ratio (BER of 1e-5), the benefit of link layer retransmissions becomes negligible due to the reduced number of packet losses. During our analysis, we notice frequent transmission of router advertisement messages causing significant overhead on L-DACS 1 and propose two approaches in order to decrease the overhead to an acceptable range. In the last section, we tackle the increase in handover delay due to a limited number of return link resource request opportunities in congested cells.

关键词： Delay Bit error rate Automatic repeat request Proposals Protocols Mobile communication Resource management

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Complexity reduction using the Random Forest classifier in a collision detection algorithm

Complexity reduction using the Random Forest classifier in a...

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IEEE Symposium on Intelligent Vehicle

作者： Michael Botsch Christoph Lauer Department for Active and Passive Safety AUDI AG Ingolstadt Germany Department for Computer Science 7 Networks and Communication Systems University of Erlangen Nuremberg Erlangen Germany

Advanced proactive safety applications are considered a promising approach to increase the effectiveness of already highly optimized vehicular safety systems. Detecting an unavoidable crash situation before the actual collision is of utmost importance and requires an effective real-time implementation. In this paper a collision detection algorithm based on the curvilinear-motion model for trajectory estimation is presented. The algorithm takes into account the EGO-vehicle's driving state and the high-level representation of surrounding objects. Next the presented approach is evaluated from a real-time perspective by applying static code analysis to a reference implementation of the algorithm. The results suggest the application of further optimization techniques as the computational complexity does not allow an effective real-time behavior. In order to guarantee both real-time constraints and effective collision detection a novel method for the preselection of potential collision opponents based on the Random Forest classifier is employed. The combination of efficient preselection and the proposed collision detection algorithm leads to a highly effective context interpretation that does not neglect the tight economic constraints.

关键词： Detection algorithms Vehicle safety Application software Timing Automotive engineering Algorithm design and analysis Road accidents Road safety computer architecture Real time systems

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Constellation Design for Odd-Bit Quadrature Amplitude Modulation

Constellation Design for Odd-Bit Quadrature Amplitude Modula...

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IEEE Wireless communications and Networking Conference Workshops (WCNCW)

作者： Yiling Wu Yuping Zhao Hongbin Li State Key Laboratory of Advanced Optical Communication Systems & Networks School of Electronics Engineering and Computer Science Peking University Beijing China

ISBN: (纸本)9781424464050;9781424464067

In this paper, we study the constellation design of quadrature amplitude modulations (QAMs) with odd number of bits per symbol. A square constellation, which adopts symmetrical Gray labeling, is proposed. Simplified mapping and demapping methods are also designed for it. Performance of the proposed square constellation is compared with that of conventional rectangular and cross constellations. As simulation results show, the proposed square constellation obtains better BER performance when channel coding is used in communication systems. Moreover, it achieves much lower realization complexity than cross constellation by using the proposed mapping and demapping method.

关键词： Quadrature amplitude modulation Labeling Peak to average power ratio Bit error rate Design methodology Channel coding Frequency estimation Optical design Laboratories Optical fiber communication

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Truly random number generation based on measurement of phase noise of a laser

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Physical Review E 2010年第5期81卷 051137-051137页

作者： Hong Guo Wenzhuo Tang Yu Liu Wei Wei CREAM Group State Key Laboratory of Advanced Optical Communication Systems and Networks (Peking University) and Institute of Quantum Electronics School of Electronics Engineering and Computer Science Peking University Beijing 100871 China

We present a simple approach to realize truly random number generator based on measuring the phase noise of a single-mode vertical cavity surface emitting laser. The true randomness of the quantum phase noise originates from the spontaneous emission of photons and the random bit generation rate is ultimately limited only by the laser linewidth. With the final bit generation rate of 20 Mbit/s, the truly random bit sequence guaranteed by the uncertainty principle of quantum mechanics passes the three standard randomness tests (ENT, Diehard, and NIST Statistical Test Suites). Moreover, a continuously generated random bit sequence, with length up to 14 Gbit, is verified by two additional criteria for its true randomness.

关键词： Phase noise

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