764 research outputs found

    A high speed Tri-Vision system for automotive applications

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    Purpose: Cameras are excellent ways of non-invasively monitoring the interior and exterior of vehicles. In particular, high speed stereovision and multivision systems are important for transport applications such as driver eye tracking or collision avoidance. This paper addresses the synchronisation problem which arises when multivision camera systems are used to capture the high speed motion common in such applications. Methods: An experimental, high-speed tri-vision camera system intended for real-time driver eye-blink and saccade measurement was designed, developed, implemented and tested using prototype, ultra-high dynamic range, automotive-grade image sensors specifically developed by E2V (formerly Atmel) Grenoble SA as part of the European FP6 project – sensation (advanced sensor development for attention stress, vigilance and sleep/wakefulness monitoring). Results : The developed system can sustain frame rates of 59.8 Hz at the full stereovision resolution of 1280 × 480 but this can reach 750 Hz when a 10 k pixel Region of Interest (ROI) is used, with a maximum global shutter speed of 1/48000 s and a shutter efficiency of 99.7%. The data can be reliably transmitted uncompressed over standard copper Camera-Link® cables over 5 metres. The synchronisation error between the left and right stereo images is less than 100 ps and this has been verified both electrically and optically. Synchronisation is automatically established at boot-up and maintained during resolution changes. A third camera in the set can be configured independently. The dynamic range of the 10bit sensors exceeds 123 dB with a spectral sensitivity extending well into the infra-red range. Conclusion: The system was subjected to a comprehensive testing protocol, which confirms that the salient requirements for the driver monitoring application are adequately met and in some respects, exceeded. The synchronisation technique presented may also benefit several other automotive stereovision applications including near and far-field obstacle detection and collision avoidance, road condition monitoring and others.Partially funded by the EU FP6 through the IST-507231 SENSATION project.peer-reviewe

    The Impact of Higher Order Pulse Amplitude Modulation and Transmission Performance over Twisted Pair Cable

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    The digital age makes it possible to be globally networked at any time. Digital communication is therefore an important aspect of today’s world. Hence, the further development and expansion of this is becoming increasingly important. Even within a wireless system, copper channels are important as part of the overall network. Given the need to keep pushing at the current limitations, careful design of the cables in connection with an adapted coding of the bits is essential to transmit more and more data. One of the most popular and widespread cabling technologies is symmetrical copper cabling [1, pp. 8-15]. It is also known as Twisted Pair and it is of immense importance for the cabling of communication networks. At the time of writing this thesis, data rates of up to 10 GBit/s over a transmission distance of 100 m and 40 GBit/s over a transmission distance of 30 m are standardized for symmetrical copper cabling [2]. Other lengths are not standardized. Short lengths in particular are of great interest for copper cables, because copper cables are usually used for short distances, such as between computers and the campus network or within data centres. This work has focused on the transmission of higher order Pulse Amplitude Modulation and the associated transmission performance. The central research question is:“how well can we optimize the transmission technique in order to be able to maximise the data bandwidth over Ethernet cable and, given that remote powering is also a significant application of these cables, how much will the resulting heating affect this transmission and what can be done to mitigate that?” To answer this question, the cable parameters are first examined. A series of spectral measurements, such as Insertion Loss, Return Loss, Near End Crosstalk and Far End Crosstalk, provide information about the electromagnetic interference and the influence of the ohmic resistance on the signal. Based on these findings, the first theoretical statements and calculations can be made. In the next step, data transmissions over different transmission lengths are realized. The examination of the eye diagrams of the different transmission approaches ultimately provides information about the signal quality of the transmissions. An overview of the maximum transmission rate depending on the transmission distance shows the potential for different applications. Furthermore, the simultaneous transmission of energy and data is a significant advantage of copper. However, the resulting heat development has an influence on the data transmission. Therefore, the influence of the ambient temperature of cables is investigated in the last part and changes in the signal quality are clarified.The research project at Reutlingen University was funded by the Federal Republic of Germany (funding code: 03TNG008A

    FGQT Q04 - Standardization Roadmap on Quantum Technologies [written by the CEN-CENELEC Focus Group on Quantum Technologies (FGQT)]

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    In 2018, the European Commission launched its long term and large scale Quantum Technology FET Flagship Program. The European Commission is also very interested in boosting standards for quantum technologies (QT). The Quantum Flagship has its own cooperation and coordination activities to “coordinate national strategies and activities” and in its “Quantum Manifesto” [1] explicitly advises to form “advisory boards” to promote collaboration in standardization. The CEN/CENELEC Focus Group for Quantum Technologies (FGQT) was formed in June 2020 with the goal to support the plans of the Commission. Currently, a multitude of standardization activities in QT are ongoing worldwide. While there is overlap in certain areas, other areas of this wide technological field are not being addressed at all. A coordinated approach will be highly beneficial to unleash the full potential of standardization for speeding up progress—also because the pool of standardization experts available for quantum technologies is still very limited. Furthermore, not all areas are yet “ready for standardization”, i.e., while in some fields early standardization is capable of boosting progress, it may be a problem in other areas. Thus, an assessment of standardization readiness of the different areas is required, too. The FGQT was established to identify standardization needs and opportunities for the entire field of QT with the final goal to boost the establishment of new industries in Europe and consequently the development and engineering of unprecedented novel devices and infrastructures for the benefit of European citizens. The QT standardization roadmap follows a constructive approach, starting with basic enabling technologies, from which QT components and subsystems are constructed, which again are assembled into QT systems that in turn form composite systems, constituting the building blocks for use cases. Thus, the roadmap is structured approximating very closely the categories of the EC quantum technology FET Flagship Program: quantum communication, quantum computing and simulation, quantum metrology, sensing, and enhanced imaging, while the basic enabling technologies and sub-systems are organized in two pools —thus supporting re-use in the different system categories. The separate types of QT unit systems are then foundations of general QT infrastructures or composite systems. On the level of use cases, the QT standardization roadmap describes basic domains of applicability, so-called “meta use cases”, while the detailed use cases are listed in a separate document of the FGQT: “FGQT Q05 Use Cases”. Finally, the QT standardization roadmap presents an outlook and conclusions, including an actual prioritization of the single identified standardization needs in the form of sequence diagrams (Gantt charts). This approach differs slightly from the QT “Pillar design” of the EU Quantum Flagship but, in our opinion, it extends it and is better adapted to standardization purposes, while the former is optimally suited as a research program design. The FGQT is an open group of European-based experts, working in QT research areas or enabling technologies, and of developers of components, products, or services related to QT. If you are based in Europe, and interested in guidelines and standards to help setting up a research infrastructure, or structuring and boosting your market relevance; if you want to improve coordination with your stakeholders and are interested in coordination and exchange with other experts in the field of QT—please consider to join the CEN/CENELEC FGQT. NOTE 1 European QT standards development in CEN/CENELEC will take place in the new JTC 22 QT (Joint Technical Committee 22 on Quantum Technologies). The work in JTC 22 QT will be guided by the present roadmap doc ument, and it is expected that the FGQT roadmap-development activity will be absorbed/continued by JTC 22 Q

    Distributed Ship Service Systems Architecture in The Early Stages of Designing Physically Large and Complex Vessels: The Submarine Case

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    In the initial sizing of complex vessels, where recourse to type ship design can be overly restrictive, one crucial set of design features has traditionally been poorly addressed. This is the estimation of the weight and space demands of the various Distributed Ship Services Systems (DS3), which include different types of commodity services beyond those primarily associated with the ship propulsion system. In general, naval vessels are typified by extensive and densely engineered DS3, with the modern naval submarine being at the extreme of dense outfitting. Despite this, the ability for the concept designer to consider the impact of different configurations for the DS3 arrangements has not been readily addressed in concept design. This paper describes ongoing work at University College London (UCL) to develop a novel DS3 synthesis approach utilising computer tools, such as Paramarine™, MATLAB®, and CPLEX®, which provide the concept designer with a quantitative network-based evaluation to enable DS3 space and weight inputs early in the design process. The results of applying the approach to a conventional submarine case study indicate quantitative insights into early DS3 sizing can be obtained. The paper concludes with likely developments in concluding the research study

    GUIDELINES FOR THE DESIGN OF ENHANCED, COST EFFECTIVE NETWORKS IN A MANUFACTURING ENVIRONMENT

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    Investigations into the transmission of real-time interactive speech over local area networks (LAN) in an industriai/commerciai environment to eventually obviate the need for a private automatic branch exchange and ultimately prepare the way for a single interactive integrated information system (PS) that provides work stations, which are networked via a LAN, with a fully interactive speech and graphics facility commensurate with the future requirements in computer integrated manufacturing (CIM). The reasons for conducting this programme of research were that existing LANs do not offer a real time interactive speech facility. Any verbal communication between workstation users on the LAN has to be carried out over a telephone network (PABX). This necessitates the provision of a second completely separate network with its associated costs. Initial investigations indicate that there is sufGcient capacity on existing LANs to support both data and real-time speech provided certain data packet delay criteria can be met. Earlier research work (in the late 1980s) has been conducted at Bell Labs and MIT. [Ref 25, 27 & 28], University of Strathclyde [Ref 24] and at BTRL [Ref 22 and 37]. In all of these cases the real time implementation issues were not fijlly addressed. In this thesis the research work reported provides the main criteria for the implementation of real-time interactive speech on both existing and newly installed networks. With such enhanced communication facilities, designers and engineers on the shop floor can be projected into their suppliers, providing a much greater integration between manufacturer and supplier which will be beneficial as Concurrent and Simultaneous Engineering Methodologies are further developed. As a result, various LANs have been evaluated as to their suitability for the transmission of real time interactive speech. As LANs, in general, can be separated into those with either deterministic or stochastic access mechanisms, investigations were carried out into the ability of both the: (i) Token Passing Bus LANs supporting the Manufacturing and Automation Protocol (MAP)—Deterministic and (u) Carrier Sense Multiple Access/Collision Detection (CSMA/CD) LANs supporting the Technical Office Protocol (TOP)— Stochastic to support real time interactive speech, as both are used extensively in commerce and manufacturing. The thesis that real time interactive speech can be transmitted over LANs employed in a computer integrated manufacturing environment has to be moderated following the tests carried out in this work, as follows:- The Token Passing LAN presents no serious problems under normal traffic conditions, however, the CSMA/CD LAN can only be used in relatively light traffic conditions i.e. below 30% of its designed maximum capacity, providing special arrangements are made to minimise the access, transmission and processing delays of speech packets. Given that a certain amount of delay is inevitable in packet switched systems (LANs), investigations have been carried out into techniques for reducing the subjective efifect of speech packet loss on real-time interactive systems due to the unacceptable delays caused by the conditions mentioned above

    Measurement of Electromagnetic Noise Coupling and Signal Mode Conversion in Data Cabling

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    Nonuniformity in transmission lines is known to be one of the causes of electromagnetic compatibility (EMC) and signal integrity (SI) issues, especially at high frequencies. This may include unpredictability in the manufacturing process, design constraints, tolerances in the values of terminal components, pigtail effects, etc., that can generate, common mode currents – with resultant degradation of signal performance of transmission lines with respect to ground. All these phenomena are capable of converting the desired differential mode (DM) signal into the unwanted common mode (CM) signal and vice versa. This study looks at cable nonuniformity resulting from irregular cable twists in twisted pair cabling, using the Category 6 UTP as an example, and considers this phenomenon responsible for signal mode conversion. Although twisted pair cables are generally often regarded as balanced transmission lines, the study shows that signal mode conversion is capable of twisted pair cables, and that makes twisted pair cabling a non-ideal balanced transmission line. However, it is difficult to analyse nonuniformity using differential equations because of the changing per-unit-length (p.u.l) parameters throughout an entire line length. Because of this, experimental measurements based on mixed-mode s-parameters analysis are designed and used to show that twisted pair cables can convert a differential mode signal to common mode signal and thus cause radiated emissions to the circuit environment. A vital contribution of this study is in the measurement techniques used. Similarly, a common mode signal (represented by an externally generated noise signal) can couple onto the transmission line, and because of the physical structure of the line, the line could become susceptible to external noise. These phenomena are not associated with ideal balanced transmission lines. In either case, if the mode conversion is not minimized, it has the potential to affect the performance of the twisted pair transmission line in terms of bit error rate. Bit error rate, BER, is basically the average rate at which transmitted errors occur in a communication system due to noise and is defined as the number of bits in error divided by the total number of bits transmitted. Therefore, reducing mode conversion in a transmission line helps to reduce the bit error rate and indeed minimise crosstalk in the communication channel. The experiments were conducted using a 4-Port Vector Network Analyser. The significance of using the 4-port VNA is that it has a general application in cable parameter measurement in the absence of specialized/customized measuring instruments. Nonetheless, with some transmission line assumptions based on the Telegrapher’s equation and applying the concept of modal decomposition, the mechanisms of signal mode conversion could be recognised. Consequently, an approximate first step symbolic solution to identifying EM radiation and hence DM-to-CM conversion and vice versa in data cable were proposed.Tertiary Education Trust Fund (Nigeria

    A new fault-tolerant configuration for the Cambridge Ring: the Hierarchical Ring-Star

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    The primary objective of this research is to look at ways of resolving the reliability problems of the Cambridge Ring local area network system. The result is a novel design to enhance the Cambridge Ring with fault tolerance by introducing redundant communication paths with dynamic reconfiguration. The proposed Ring-Star system combines the advantages of ring and star networks to create a network which is topologically resilient while retaining the efficient communication advantage of rings. [Continues.

    Performance Enhancement in Copper Twisted Pair Cable Communications

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    The thesis focuses on the area of copper twisted pair based wireline communications. As one of the most widely deployed communication media, the copper twisted pair cable plays an important role in the communication network cabling infrastructure. This thesis looks to exploit diversity to improve twisted pair channels for data communications in two common application areas, namely Ethernet over Twisted Paris and digital subscriber line over twisted pair based telephone network. The first part of the thesis addresses new approaches to next generation Ethernet over twisted pair cable. The coming challenge for Ethernet over twisted pair cable is to realise a higher data rate beyond the 25/40GBASE-T standard, in relatively short reach scenarios. The straight-forward approaches, such as improving cable quality and extending frequency bandwidth, are unlikely to provide significant improvement in terms of data rate. However, other system diversities, such as spectrum utilization are yet to be fully exploited, so as to meet the desired data rate performance. The current balanced transmission over the structured twisted pair cable and its parallel single-in-single-out channel model is revisited and formulated as a full-duplex multiple-in-multiple-out (MIMO) channel model. With a common ground (provided by the cable shield), the balanced transmission is converted into unbalanced transmission, by replacing the differential-mode excitation with single-ended excitation. In this way, MIMO adoption may offer spectrum utilization advantages due to the doubled number of the channels. The S-parameters of the proposed MIMO channel model is obtained through the full wave electromagnetic simulation of a short CAT7A cable. The channel models are constructed from the resulting S-parameters, also the corresponding theoretical capacity is evaluated by exploiting different diversity scenarios. With higher spectrum efficiency, the orthogonal-frequency-division-multiplexing (OFDM) modulation can significantly improve the theoretical capacity compared with single-carrier modulation, where the channel frequency selectivity is aided. The MIMO can further enhance the capacity by minimising the impact of the crosstalk. When the crosstalk is properly handled under the unbalanced transmission, this thesis shows that the theoretical capacity of the EoTP cable can reach nearly 200GBit/s. In order to further extend the bandwidth capability of twisted pair cables, Phantom Mode transmission is studied, aiming at creating more channels under balanced transmission operation. The second part of the thesis focuses on the research of advanced scheduling algorithms for VDSL2 QoS enhancement. For VDSL2 broadband access networks, multi-user optimisation techniques have been developed, so as to improve the basic data rate performance. Spectrum balancing improves the network performance by optimising users transmit power spectra as the resource allocation, to mitigate the impact from the crosstalk. Aiming at enhancing the performance for the upstream VDSL2 service, where the users QoS demand is not known by all other users, a set of autonomous spectrum balancing algorithms is proposed. These optimise users transmit power spectra locally with only direct channel state information. To prevent selfish behaviour, the concept of a virtual user is introduced to represent the impact on both crosstalk interference and queueing status of other users. Moreover, novel algorithms are developed to determine the parameters and the weight of the virtual user. Another type of resource allocation in the VDSL2 network is crosstalk cancellation by centralised signal coordination. The history of the data queue is considered as a time series, on which different smooth filter characteristics are investigated in order to investigate further performance improvement. The use of filter techniques accounts for both the instantaneous queue length and also the previous data to determine the most efficient dynamic resource allocation. With the help of this smoothed dynamic resource allocation, the network will benefit from both reduced signalling communication and improved delay performance.The proposed algorithms are verified by numerical experiments
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