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Статті в журналах з теми "Operating system redundancy techniques"
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Michlowicz, Edward, and Jerzy Wojciechowski. "A method for evaluating and upgrading systems with parallel structures with forced redundancy." Eksploatacja i Niezawodnosc - Maintenance and Reliability 23, no. 4 (October 17, 2021): 770–76. http://dx.doi.org/10.17531/ein.2021.4.19.
Повний текст джерелаАнотація:
The objects of the study are parallel-structure machine systems with redundancy associated with safety assurance of continuous material flow. The problem concerns systems in which the supply of materials takes place continuously (24 hours a day), and the system of operated machines must ensure the receipt and movement of the material at a strictly defined time and in the desired quantity. It is a system where the presence of a failure poses a threat to human life and environmental degradation. This paper presents a method for system condition assessment and upgrading for maintaining proper operation under conditions of continuous operation. A database of information about the current parameters of the system components (measurements, monitoring) is necessary for condition assessment. The method also uses lean techniques (including TPM). System evaluation and selection criteria for a suitable structure in terms of further operation were proposed. Exemplification was performed for an underground mine drainage system. As a part of the identification, selected parameters of the system components were measured, and their characteristics (motors, pumps, pipelines) were developed. The results of the analysis and the values of the adopted criteria were compared to the indicators for new pump sets. A two-option system upgrade was proposed, in addition to machine operating schedules, maintenance periods, and overhaul cycles.
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Shurtleff, Mark S., Joseph A. Jenkins, and Michelle R. Sams. "Deriving Menu Structures through Modal Block Clustering: A Promising Alternative to Hierarchical Techniques." Proceedings of the Human Factors Society Annual Meeting 32, no. 5 (October 1988): 347–51. http://dx.doi.org/10.1177/154193128803200525.
Повний текст джерелаАнотація:
Modal block clustering (MBC) is proposed as an approach more suited to the derivation of menu structures than hierarchical clustering techniques. Problems with the application of hierarchical techniques and pairwise similarity ratings (PWSR) from which the clusters are derived are discussed. MBC defines clusters based on the pattern of common command attributes and provides an objective way to determine the composition and number of menu panels to include in a menu structure. The method also objectively defines command redundancy for the menu panels. The method of MBC was applied to the 97 commands that comprise the CMS operating system resulting in 17 menu categories. The menu categories were used to design a help menu system. The MBC procedure provides a viable methodology for complex systems, such as CMS, which derive increased functionality from numerous command options. System designers can fruitfully and efficiently apply this methodology both to current systems and to proposed systems for which there are no expert users.
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Wang, Hui, and Yun Wang. "Designing Fault Tolerance Strategy by Iterative Redundancy for Component-Based Distributed Computing Systems." Mathematical Problems in Engineering 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/197423.
Повний текст джерелаАнотація:
Reliability is a critical issue for component-based distributed computing systems, some distributed software allows the existence of large numbers of potentially faulty components on an open network. Faults are inevitable in this large-scale, complex, distributed components setting, which may include a lot of untrustworthy parts. How to provide highly reliable component-based distributed systems is a challenging problem and a critical research. Generally, redundancy and replication are utilized to realize the goal of fault tolerance. In this paper, we propose a CFI (critical fault iterative) redundancy technique, by which the efficiency can be guaranteed to make use of resources (e.g., computation and storage) and to create fault-tolerance applications. When operating in an environment with unknown components’ reliability, CFI redundancy is more efficient and adaptive than other techniques (e.g., K-Modular Redundancy and N-Version Programming). In the CFI strategy of redundancy, the function invocation relationships and invocation frequencies are employed to rank the functions’ importance and identify the most vulnerable function implemented via functionally equivalent components. A tradeoff has to be made between efficiency and reliability. In this paper, a formal theoretical analysis and an experimental analysis are presented. Compared with the existing methods, the reliability of components-based distributed system can be greatly improved by tolerating a small part of significant components.
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HEIDERGOTT, W. F. "SYSTEM LEVEL SINGLE EVENT UPSET MITIGATION STRATEGIES." International Journal of High Speed Electronics and Systems 14, no. 02 (June 2004): 341–52. http://dx.doi.org/10.1142/s0129156404002399.
Повний текст джерелаАнотація:
Use of a systems engineering process and the application of techniques and methods of fault tolerant systems are applicable to the development of a mitigation strategy for Single Event Upsets (SEU). Specific methods of fault avoidance, fault masking, detection, containment, and recovery techniques are important elements in the mitigation of single event upsets. Fault avoidance through the use of SEU hardened technology, fault masking using coding and redundancy provisions, and solutions applied at the subsystem and system level are available to the system developer. Validation and verification of SEU mitigation and performance of fault tolerance provisions are essential elements of systems design for operation in energetic particle environments.
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., Pankaj, Jasdev Bhatti, and Mohit Kumar Kakkar. "Reliability Analysis of Industrial Model Using Redundancy Technique and Geometric Distribution." ECS Transactions 107, no. 1 (April 24, 2022): 7273–80. http://dx.doi.org/10.1149/10701.7273ecst.
Повний текст джерелаАнотація:
The present paper is an initiative towards analyzing the maintenance process of an industrial model using regenerative techniques. With an increase in demands to analyze the reliability of any industrial models following continuous or discrete distribution, the major concern to be considered inspect the possibility and level of failure and proceeding the failed unit for further repairing process. The system consists of two parallel units following the passive standby redundancy and with different failure mechanism. The proposed analytical methodology in the paper made it possible to assess the reliability of the whole system in the event of failure of its components. The stochastic analysis of reliability characteristics of the considered system to the types of repair time distributions was also studied using geometric distribution. The numerical equations and results being calculated for reliability parameters like mean time to system failure, availability of system in operative form, down period of the system following repair mechanism, using regenerative techniques, and geometric distribution. Graphical and analytical analysis were presented.
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Ferrentino, Enrico, Federico Salvioli, and Pasquale Chiacchio. "Globally Optimal Redundancy Resolution with Dynamic Programming for Robot Planning: A ROS Implementation." Robotics 10, no. 1 (March 4, 2021): 42. http://dx.doi.org/10.3390/robotics10010042.
Повний текст джерелаАнотація:
Dynamic programming techniques have proven much more flexible than calculus of variations and other techniques in performing redundancy resolution through global optimization of performance indices. When the state and input spaces are discrete, and the time horizon is finite, they can easily accommodate generic constraints and objective functions and find Pareto-optimal sets. Several implementations have been proposed in previous works, but either they do not ensure the achievement of the globally optimal solution, or they have not been demonstrated on robots of practical relevance. In this communication, recent advances in dynamic programming redundancy resolution, so far only demonstrated on simple planar robots, are extended to be used with generic kinematic structures. This is done by expanding the Robot Operating System (ROS) and proposing a novel architecture meeting the requirements of maintainability, re-usability, modularity and flexibility that are usually required to robotic software libraries. The proposed ROS extension integrates seamlessly with the other software components of the ROS ecosystem, so as to encourage the reuse of the available visualization and analysis tools. The new architecture is demonstrated on a 7-DOF robot with a six-dimensional task, and topological analyses are carried out on both its state space and resulting joint-space solution.
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WANG, CHUN-CHING, YIH-CHUAN LIN, and CHI-YIN LIN. "ROM REDUCTION FOR OFDM SYSTEM USING TIME-STEALING STRATEGY." Journal of Circuits, Systems and Computers 15, no. 06 (December 2006): 907–21. http://dx.doi.org/10.1142/s0218126606003398.
Повний текст джерелаАнотація:
Modern communication systems frequently exploit the OFDM (Orthogonal Frequency Division Multiplex) technique to obtain a highly robust transmission of multimedia information, such as digital audio/video broadcast. OFDM and most of the other multimedia compression techniques usually require expensive computations, e.g., FFT (Fast Fourier Transform) and IMDCT (Inverse Modified Discrete Cosine Transform) processing. Traditionally, designing FFT and IMDCT separately involves a significant amount of redundancy in hardware. To reduce the required hardware, this investigation proposes a new ROM-sharing design for storing both FFT twiddle factors and IMDCT coefficients in a DAB (Digital Audio Broadcasting) receiver. We first analyze the correlation between FFT operations and IMDCT operations, and then the combinational logic circuit in the FFT processor is modified such that both IMDCT coefficients and FFT twiddle factors can be obtained simultaneously from a shared ROM. This design can also be applied for computing IFFT (Inverse Fast Fourier Transform) and MDCT for DAB transmitter. Compared with the traditional design using separate module scheme, our design does not need extra ROM for IMDCT/MDCT modules. Therefore, the new scheme offers superior solution for combining high-performance FFT (IFFT) operation and IMDCT (MDCT) operation.
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Banteywalu, Solomon, Baseem Khan, Valentijn De Smedt, and Paul Leroux. "A Novel Modular Radiation Hardening Approach Applied to a Synchronous Buck Converter." Electronics 8, no. 5 (May 8, 2019): 513. http://dx.doi.org/10.3390/electronics8050513.
Повний текст джерелаАнотація:
Radiation and extreme temperature are the main inhibitors for the use of electronic devices in space applications. Radiation challenges the normal and stable operation of DC-DC converters, used as power supply for onboard systems in satellites and spacecrafts. In this situation, special design techniques known as radiation hardening or radiation tolerant designs have to be employed. In this work, a module level design approach for radiation hardening is addressed. A module in this sense is a constituent of a digital controller, which includes an analog to digital converter (ADC), a digital proportional-integral-derivative (PID) controller, and a digital pulse width modulator (DPWM). As a new Radiation Hardening by Design technique (RHBD), a four module redundancy technique is proposed and applied to the digital voltage mode controller driving a synchronous buck converter, which has been implemented as hardware-in-the-loop (HIL) simulation block in MATLAB/Simulink using Xilinx system generator based on the Zynq-7000 development board (ZYBO). The technique is compared, for reliability and hardware resources requirement, with triple modular redundancy (TMR), five modular redundancy (FMR) and the modified triplex–duplex architecture. Furthermore, radiation induced failures are emulated by switching all duplicated modules inputs to different signals, or to ground during simulation. The simulation results show that the proposed technique has 25% and 30%longer expected life compared to TMR and FMR techniques, respectively, and has the lowest hardware resource requirement compared to FMR and the modified triplex–duplex techniques.
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Grehan, Julianne, Dmitry Ignatyev, and Argyrios Zolotas. "Fault Detection in Aircraft Flight Control Actuators Using Support Vector Machines." Machines 11, no. 2 (February 2, 2023): 211. http://dx.doi.org/10.3390/machines11020211.
Повний текст джерелаАнотація:
Future generations of flight control systems, such as those for unmanned autonomous vehicles (UAVs), are likely to be more adaptive and intelligent to cope with the extra safety and reliability requirements due to pilotless operations. An efficient fault detection and isolation (FDI) system is paramount and should be capable of monitoring the health status of an aircraft. Historically, hardware redundancy techniques have been used to detect faults. However, duplicating the actuators in an UAV is not ideal due to the high cost and large mass of additional components. Fortunately, aircraft actuator faults can also be detected using analytical redundancy techniques. In this study, a data-driven algorithm using Support Vector Machine (SVM) is designed. The aircraft actuator fault investigated is the loss-of-effectiveness (LOE) fault. The aim of the fault detection algorithm is to classify the feature vector data into a nominal or faulty class based on the health of the actuator. The results show that the SVM algorithm detects the LOE fault almost instantly, with an average accuracy of 99%.
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Ahmed, Yahye Abukar, Shamsul Huda, Bander Ali Saleh Al-rimy, Nouf Alharbi, Faisal Saeed, Fuad A. Ghaleb, and Ismail Mohamed Ali. "A Weighted Minimum Redundancy Maximum Relevance Technique for Ransomware Early Detection in Industrial IoT." Sustainability 14, no. 3 (January 21, 2022): 1231. http://dx.doi.org/10.3390/su14031231.
Повний текст джерелаАнотація:
Ransomware attacks against Industrial Internet of Things (IIoT) have catastrophic consequences not only to the targeted infrastructure, but also the services provided to the public. By encrypting the operational data, the ransomware attacks can disrupt the normal operations, which represents a serious problem for industrial systems. Ransomware employs several avoidance techniques, such as packing, obfuscation, noise insertion, irrelevant and redundant system call injection, to deceive the security measures and make both static and dynamic analysis more difficult. In this paper, a Weighted minimum Redundancy maximum Relevance (WmRmR) technique was proposed for better feature significance estimation in the data captured during the early stages of ransomware attacks. The technique combines an enhanced mRMR (EmRmR) with the Term Frequency-Inverse Document Frequency (TF-IDF) so that it can filter out the runtime noisy behavior based on the weights calculated by the TF-IDF. The proposed technique has the capability to assess whether a feature in the relevant set is important or not. It has low-dimensional complexity and a smaller number of evaluations compared to the original mRmR method. The TF-IDF was used to evaluate the weights of the features generated by the EmRmR algorithm. Then, an inclusive entropy-based refinement method was used to decrease the size of the extracted data by identifying the system calls with strong behavioral indication. After extensive experimentation, the proposed technique has shown to be effective for ransomware early detection with low-complexity and few false-positive rates. To evaluate the proposed technique, we compared it with existing behavioral detection methods.
Дисертації з теми "Operating system redundancy techniques"
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VELASCO, ALEJANDRO DAVID. "Software-based methods for Operating system dependability." Doctoral thesis, Politecnico di Torino, 2017. http://hdl.handle.net/11583/2678125.
Повний текст джерелаАнотація:
Guaranteeing correct system behaviour in modern computer systems has become essential, in particular for safety-critical computer-based systems. However all modern systems are susceptible to transient faults that can disrupt the intended operation and function of such systems. In order to evaluate the sensitivity of such systems, different methods have been developed, and among them Fault Injection is considered a valid approach widely adopted.
This document presents a fault injection tool, called Kernel-based Fault-Injection Tool Open-source (KITO), to analyze the effects of faults in memory elements containing kernel data structures belonging to a Unix-based Operating System and, in particular, elements involved in resources synchronization. This tool was evaluated in different stages of its development with different experimental analyses by performing Faults Injections in the Operating System, while the system was subject to stress from benchmark programs that use different elements of the Linux kernel. The results showed that KITO was capable of generating faults in different
elements of the operating systems with limited intrusiveness, and that the data structures belonging to synchronization aspects of the kernel are susceptible to an appreciable set of possible errors ranging from performance degradation to complete system failure, thus preventing benchmark applications to perform their task.
Finally, aiming at overcoming the vulnerabilities discovered with KITO, a couple of solutions have been proposed consisting in the implementation of hardening techniques in the source code of the Linux kernel, such as Triple Modular Redundancy and Error Detection And Correction codes. An experimental fault injection analysis has been conducted to evaluate the effectiveness of the proposed solutions. Results have shown that it is possible to successfully detect and correct the noxious effects generated by single faults in the system with a limited performance overhead in kernel data structures of the Linux kernel.
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Graves, Jamie Robert. "Forensic verification of operating system activity via novel data, acquisition and analysis techniques." Thesis, Edinburgh Napier University, 2009. http://researchrepository.napier.ac.uk/Output/6699.
Повний текст джерелаАнотація:
Digital Forensics is a nascent field that faces a number of technical, procedural and cultural difficulties that must be overcome if it is to be recognised as a scientific discipline, and not just an art. Technical problems involve the need to develop standardised tools and techniques for the collection and analysis of digital evidence. This thesis is mainly concerned with the technical difficulties faced by the domain. In particular, the exploration of techniques that could form the basis of trusted standards to scientifically verify data. This study presents a set of techniques, and methodologies that can be used to describe the fitness of system calls originating from the Windows NT platform as a form of evidence. It does so in a manner that allows for open investigation into the manner in which the activities described by this form of evidence can be verified. The performance impact on the Device Under Test (DUT) is explored via the division of the Windows NT system calls into service subsets. Of particular interest to this work is the file subset, as the system calls can be directly linked to user interaction. The subsequent quality of data produced by the collection tool is examined via the use of the Basic Local Alignment Search Tool (BLAST) sequence alignment algorithm . In doing so, this study asserts that system calls provide a recording, or time line, of evidence extracted from the operating system, which represents actions undertaken. In addition, it asserts that these interactions can be compared against known profiles (fingerprints) of activity using BLAST, which can provide a set of statistics relating to the quality of match, and a measure of the similarities of sequences under scrutiny. These are based on Karlin-Altschul statistics which provides, amongst other values, a P-Value to describe how often a sequence will occur within a search space. The manner in which these statistics are calculated is augmented by the novel generation of the NM1,5_D7326 scoring matrix based on empirical data gathered from the operating system, which is compared against the de facto, biologically generated, BLOSUM62 scoring matrix. The impact on the Windows 2000 and Windows XP DUTs of monitoring most of the service subsets, including the file subset, is statistically insignificant when simple user interactions are performed on the operating system. For the file subset, p = 0.58 on Windows 2000 Service Pack 4, and p = 0.84 on Windows XP Service Pack 1. This study shows that if the event occurred in a sequence that originated on an operating system that was not subjected to high process load or system stress, a great deal of confidence can be placed in a gapped match, using either the NM_I.5~7326 or BLOSUM62 scoring matrices, indicating an event occurred, as all fingerprints of interest (FOI) were identified. The worst-case BLOSUM62 P-Value = 1.10E-125, and worst-case NM1.5_D7326 P-Value = 1.60E-72, showing that these matrices are comparable in their sensitivity during normal system conditions. This cannot be said for sequences gathered during high process load or system stress conditions. The NM1.5_D7326 scoring matrix failed to identify any FOI. The BLOSUM62 scoring matrix returned a number of matches that may have been the FOI, as discerned via the supporting statistics, but were not positively identified within the evaluation criteria. The techniques presented in this thesis are useful, structured and quantifiable. They provide the basis for a set of methodologies that can be used for providing objective data for additional studies into this form of evidence, which can further explore the details of the calibration and analysis methods, thus supplying the basis for a trusted form of evidence, which may be described as fit-for-purpose.
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McKenney, Paul E. "Exploiting deferred destruction : an analysis of read-copy-update techniques in operating system kernels /." Full text open access at:, 2004. http://content.ohsu.edu/u?/etd,225.
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Rajagopalan, Mohan. "Optimizing System Performance and Dependability Using Compiler Techniques." Diss., Tucson, Arizona : University of Arizona, 2006. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1439%5F1%5Fm.pdf&type=application/pdf.
Повний текст джерела
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Auffarth, Benjamin. "Machine Learning Techniques with Specific Application to the Early Olfactory System." Doctoral thesis, KTH, Beräkningsbiologi, CB, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-90474.
Повний текст джерелаАнотація:
This thesis deals with machine learning techniques for the extraction of structure and the analysis of the vertebrate olfactory pathway based on related methods. Some of its main contributions are summarized below. We have performed a systematic investigation for classification in biomedical images with the goal of recognizing a material in these images by its texture. This investigation included (i) different measures for evaluating the importance of image descriptors (features), (ii) methods to select a feature set based on these evaluations, and (iii) classification algorithms. Image features were evaluated according to their estimated relevance for the classification task and their redundancy with other features. For this purpose, we proposed a framework for relevance and redundancy measures and, within this framework, we proposed two new measures. These were the value difference metric and the fit criterion. Both measures performed well in comparison with other previously used ones for evaluating features. We also proposed a Hopfield network as a method for feature selection, which in experiments gave one of the best results relative to other previously used approaches. We proposed a genetic algorithm for clustering and tested it on several realworld datasets. This genetic algorithm was novel in several ways, including (i) the use of intra-cluster distance as additional optimization criterion, (ii) an annealing procedure, and (iii) adaptation of mutation rates. As opposed to many conventional clustering algorithms, our optimization framework allowed us to use different cluster validation measures including those which do not rely on cluster centroids. We demonstrated the use of the clustering algorithm experimentally with several cluster validity measures as optimization criteria. We compared the performance of our clustering algorithm to that of the often-used fuzzy c-means algorithm on several standard machine learning datasets from the University of California/Urvine (UCI) and obtained good results. The organization of representations in the brain has been observed at several stages of processing to spatially decompose input from the environment into features that are somehow relevant from a behavioral or perceptual standpoint. For the perception of smells, the analysis of such an organization, however, is not as straightforward because of the missing metric. Some studies report spatial clusters for several combinations of physico-chemical properties in the olfactory bulb at the level of the glomeruli. We performed a systematic study of representations based on a dataset of activity-related images comprising more than 350 odorants and covering the whole spatial array of the first synaptic level in the olfactory system. We found clustered representations for several physico-chemical properties. We compared the relevance of these properties to activations and estimated the size of the coding zones. The results confirmed and extended previous studies on olfactory coding for physico-chemical properties. Particularly of interest was the spatial progression by carbon chain that we found. We discussed our estimates of relevance and coding size in the context of processing strategies. We think that the results obtained in this study could guide the search into olfactory coding primitives and the understanding of the stimulus space. In a second study on representations in the olfactory bulb, we grouped odorants together by perceptual categories, such as floral and fruity. By the application of the same statistical methods as in the previous study, we found clustered zones for these categories. Furthermore, we found that distances between spatial representations were related to perceptual differences in humans as reported in the literature. This was possibly the first time that such an analysis had been done. Apart from pointing towards a spatial decomposition by perceptual dimensions, results indicate that distance relationships between representations could be perceptually meaningful. In a third study, we modeled axon convergence from olfactory receptor neurons to the olfactory bulb. Sensory neurons were stimulated by a set of biologically-relevant odors, which were described by a set of physico-chemical properties that covaried with the neural and glomerular population activity in the olfactory bulb. Convergence was mediated by the covariance between olfactory neurons. In our model, we could replicate the formation of glomeruli and concentration coding as reported in the literature, and further, we found that the spatial relationships between representational zones resulting from our model correlated with reported perceptual differences between odor categories. This shows that natural statistics, including similarity of physico-chemical structure of odorants, can give rise to an ordered arrangement of representations at the olfactory bulb level where the distances between representations are perceptually relevant.QC 20120224
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Vasudevan, Siddarth. "Design and Development of a CubeSat Hardware Architecture with COTS MPSoC using Radiation Mitigation Techniques." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-285577.
Повний текст джерелаАнотація:
CubeSat missions needs components that are tolerant against the radiation in space. The hardware components must be reliable, and it must not compromise the functionality on-board during the mission. At the same time, the cost of hardware and its development should not be high. Hence, this thesis discusses the design and development of a CubeSat architecture using a Commercial Off-The- Shelf (COTS) Multi-Processor System on Chip (MPSoC). The architecture employs an affordable Rad-Hard Micro-Controller Unit as a Supervisor for the MPSoC. Also, it uses several radiation mitigation techniques such as the Latch-up protection circuit to protect it against Single-Event Latch-ups (SELs), Readback scrubbing for Non- Volatile Memories (NVMs) such as NOR Flash and Configuration scrubbing for the FPGA present in the MPSoC to protect it against Single-Event Upset (SEU)s, reliable communication using Cyclic Redundancy Check (CRC) and Space packet protocol. Apart from such functionalities, the Supervisor executes tasks such as Watchdog that monitors the liveliness of the applications running in the MPSoC, data logging, performing Over-The-Air Software/Firmware update. The thesis work implements functionalities such as Communication, Readback memory scrubbing, Configuration scrubbing using SEM-IP, Watchdog, and Software/Firmware update. The execution times of the functionalities are presented for the application done in the Supervisor. As for the Configuration scrubbing that was implemented in Programmable Logic (PL)/FPGA, results of area and latency are reported.CubeSat-uppdrag behöver komponenter som är toleranta mot strålningen i rymden. Maskinvarukomponenterna måste vara pålitliga och funktionaliteten ombord får inte äventyras under uppdraget. Samtidigt bör kostnaden för hårdvara och dess utveckling inte vara hög. Därför diskuterar denna avhandling design och utveckling av en CubeSatarkitektur med hjälp av COTS (eng. Custom-off-The-Shelf) MPSoC (eng. Multi Processor System-on-Chip). Arkitekturen använder en prisvärd strålningshärdad (eng. Rad-Hard) Micro-Controller Unit(MCU) som Övervakare för MPSoC:en och använder också flera tekniker för att begränsa strålningens effekter såsom kretser för att skydda kretsen från s.k. Single Event Latch-Ups (SELs), återläsningsskrubbning för icke-volatila minnen (eng. Non-Volatile Memories) NVMs som NOR Flash och skrubbning av konfigurationsminnet skrubbning för FPGA:er i MPSoC:en för att skydda dem mot Single-Event Upsets (SEUs), och tillhandahålla pålitlig kommunikation mha CRC och Space Packet Protocol. Bortsett från sådana funktioner utför Övervakaren uppgifter som Watchdog för att övervaka att applikationerna som körs i MPSoC:en fortfarande är vid liv, dataloggning, och Over- the-Air-uppdateringar av programvaran/Firmware. Examensarbetet implementerar funktioner såsom kommunikation, återläsningsskrubbning av minnet, konfigurationsminnesskrubbning mha SEM- IP, Watchdog och uppdatering av programvara/firmware. Exekveringstiderna för utförandet av funktionerna presenteras för den applikationen som körs i Övervakaren. När det gäller konfigurationsminnesskrubbningen som implementerats i den programmerbara logiken i FPGA:n, rapporteras area och latens.
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Djedidi, Oussama. "Modélisation incrémentale des processeurs embarqués pour l'estimation des caractéristiques et le diagnostic." Electronic Thesis or Diss., Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0639.
Повний текст джерелаАнотація:
Les systèmes-sur-puce (Systems on Chip, SoC) sont de plus en plus embarqués dans des systèmes à risque comme les systèmes aéronautiques et les équipements de production d’énergie. Cette évolution technologique permet un gain de temps et de performance, mais présente des limites en termes de fiabilité et de sécurité. Ainsi, le développement d’outils de surveillance et de diagnostic des systèmes électroniques embarqués, en particuliers les SoC, est devenu l’un des verrous scientifiques à lever pour assurer une large utilisation de ces systèmes dans les équipements à risque en toute sécurité. Ce travail de thèse s’inscrit dans ce contexte, et a pour objectif le développement d’une approche de détection et identification des dérives des performances des SoC embarqués. L’approche proposée est basée sur un modèle incrémental, construit à partir de modules réutilisables et échangeables pour correspondre à la large gamme de SoC existants sur le marché. Le modèle est ensuite utilisé pour estimer un ensemble de caractéristiques relatives à l’état de fonctionnement du SoC. L’algorithme de diagnostic développé dans ce travail consiste à générer des indices de dérives par la comparaison en ligne des caractéristiques estimées à celles mesurées. L’évaluation des résidus et la prise de décision sont réalisées par des méthodes statistiques appropriées à la nature de chaque indice de dérive. L’approche développée a été validée expérimentalement sur des SoC différents, ainsi que sur un démonstrateur développé dans le cadre de ce travail. Les résultats expérimentaux obtenus, montrent l’efficacité et la robustesse de l’approche développéeSystems on Chip are increasingly embedded in safety-critical systems, such as aeronautical systems and energy production equipment. Such technological evolution allows for significant improvements in performance but presents limits in terms of reliability and security. Therefore, the development of new tools for the monitoring and diagnosis of embedded electronic systems, Systems on Chip, in particular is currently one of the scientific challenges to overcome, in order to ensure a broader and safer use of these systems in safety-critical equipment. The work presented in this thesis aims to develop an approach for detecting and identifying drifts in embedded Systems of Chips characteristics and performance. The proposed approach is based on an incremental model built from reusable and exchangeable modules able to adapt and accommodate the broad range of Systems on Chips available on the market. This model is then used to estimate a set of characteristics relating to the state of operation of the SoC. The diagnostic algorithm developed in this work consists of generating drift signals though the online comparison of the estimated characteristics to those measured. Then, the assessment of residuals and decision making are performed by statistical methods appropriate to the nature of each drift. The developed approach has been experimentally validated on different Systems on Chip, as well as on a demonstrator developed as part of this work. The obtained experimental results validate and show the efficiency and robustness of the incremental model and the monitoring algorithm
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Mallangi, Siva Sai Reddy. "Low-Power Policies Based on DVFS for the MUSEIC v2 System-on-Chip." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-229443.
Повний текст джерелаАнотація:
Multi functional health monitoring wearable devices are quite prominent these days. Usually these devices are battery-operated and consequently are limited by their battery life (from few hours to a few weeks depending on the application). Of late, it was realized that these devices, which are currently being operated at fixed voltage and frequency, are capable of operating at multiple voltages and frequencies. By switching these voltages and frequencies to lower values based upon power requirements, these devices can achieve tremendous benefits in the form of energy savings. Dynamic Voltage and Frequency Scaling (DVFS) techniques have proven to be handy in this situation for an efficient trade-off between energy and timely behavior. Within imec, wearable devices make use of the indigenously developed MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). This system is optimized for efficient and accurate collection, processing, and transfer of data from multiple (health) sensors. MUSEIC v2 has limited means in controlling the voltage and frequency dynamically. In this thesis we explore how traditional DVFS techniques can be applied to the MUSEIC v2. Experiments were conducted to find out the optimum power modes to efficiently operate and also to scale up-down the supply voltage and frequency. Considering the overhead caused when switching voltage and frequency, transition analysis was also done. Real-time and non real-time benchmarks were implemented based on these techniques and their performance results were obtained and analyzed. In this process, several state of the art scheduling algorithms and scaling techniques were reviewed in identifying a suitable technique. Using our proposed scaling technique implementation, we have achieved 86.95% power reduction in average, in contrast to the conventional way of the MUSEIC v2 chip’s processor operating at a fixed voltage and frequency. Techniques that include light sleep and deep sleep mode were also studied and implemented, which tested the system’s capability in accommodating Dynamic Power Management (DPM) techniques that can achieve greater benefits. A novel approach for implementing the deep sleep mechanism was also proposed and found that it can obtain up to 71.54% power savings, when compared to a traditional way of executing deep sleep mode.Nuförtiden så har multifunktionella bärbara hälsoenheter fått en betydande roll. Dessa enheter drivs vanligtvis av batterier och är därför begränsade av batteritiden (från ett par timmar till ett par veckor beroende på tillämpningen). På senaste tiden har det framkommit att dessa enheter som används vid en fast spänning och frekvens kan användas vid flera spänningar och frekvenser. Genom att byta till lägre spänning och frekvens på grund av effektbehov så kan enheterna få enorma fördelar när det kommer till energibesparing. Dynamisk skalning av spänning och frekvens-tekniker (såkallad Dynamic Voltage and Frequency Scaling, DVFS) har visat sig vara användbara i detta sammanhang för en effektiv avvägning mellan energi och beteende. Hos Imec så använder sig bärbara enheter av den internt utvecklade MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). Systemet är optimerat för effektiv och korrekt insamling, bearbetning och överföring av data från flera (hälso) sensorer. MUSEIC v2 har begränsad möjlighet att styra spänningen och frekvensen dynamiskt. I detta examensarbete undersöker vi hur traditionella DVFS-tekniker kan appliceras på MUSEIC v2. Experiment utfördes för att ta reda på de optimala effektlägena och för att effektivt kunna styra och även skala upp matningsspänningen och frekvensen. Eftersom att ”overhead” skapades vid växling av spänning och frekvens gjordes också en övergångsanalys. Realtidsoch icke-realtidskalkyler genomfördes baserat på dessa tekniker och resultaten sammanställdes och analyserades. I denna process granskades flera toppmoderna schemaläggningsalgoritmer och skalningstekniker för att hitta en lämplig teknik. Genom att använda vår föreslagna skalningsteknikimplementering har vi uppnått 86,95% effektreduktion i jämförelse med det konventionella sättet att MUSEIC v2-chipets processor arbetar med en fast spänning och frekvens. Tekniker som inkluderar lätt sömn och djupt sömnläge studerades och implementerades, vilket testade systemets förmåga att tillgodose DPM-tekniker (Dynamic Power Management) som kan uppnå ännu större fördelar. En ny metod för att genomföra den djupa sömnmekanismen föreslogs också och enligt erhållna resultat så kan den ge upp till 71,54% lägre energiförbrukning jämfört med det traditionella sättet att implementera djupt sömnläge.
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Heinzlef, Charlotte. "Modélisation d'indicateurs de résilience urbaine face au risque d'inondation : co-construction d'un système spatial à la décision pour contribuer à l'opérationnalisation du concept de résilience Assessing and mapping urban resilience to floods with respect to cascading effects through critical infrastructure networks » Operationalizing urban resilience to floods in embanked territories – Application in Avignon, Provence Alpes Côte d’azur region A spatial decision support system for enhancing resilience to floods. Bridging resilience modelling and geovisualization techniques Operating urban resilience strategies to face climate change and associated risks: some advances from theory to application in Canada and France." Thesis, Avignon, 2019. http://www.theses.fr/2019AVIG1197.
Повний текст джерелаАнотація:
Dans un contexte de dérèglement climatique, d’augmentation des inondations en milieu urbain,d’augmentation des incertitudes, les gestionnaires urbains sont obligés d’innover pour concevoir des stratégies de gestion des risques adéquates. Parmi ces stratégies, rendre les villes résilientes est devenu un impératif. Le concept de résilience est un concept pluridisciplinaire qui définit la capacité d’un système à absorber une perturbation et à récupérer ses fonctions par la suite. Cette notion renvoie à une innovation technique, urbaine, sociale, architecturale, économique et politique et enjoint à une remise en question des stratégies traditionnelles de gestion du risque. Cette injonction à l’innovation s’adapte parfaitement à la complexité urbaine, économique, politique, sociale, écologique du monde contemporain. De ce fait, le concept de résilience s’intègre aux enjeux d’étalement urbain et aux risques associés. Pourtant, malgré cette adéquation théorique et conceptuelle, la résilience demeure complexe à intégrer dans les pratiques des urbanistes et acteurs territoriaux. Sa multitude de définitions et d’approches a favorisé son abstraction et son manque d’opérationnalisation. Face à ce constat, cette recherche se propose de répondre à ces lacunes opérationnelles en construisant un système spatial d’aide à la décision afin de clarifier et favoriser l’intégration du concept dans les pratiques urbaines. L’idée défendue est que la résilience urbaine incarne les aptitudes et capacités d’une ville et de sa population à mettre en place avant, pendant et après un événement perturbateur de façon à en limiter les impacts négatifs. Ce positionnement scientifique permet donc d’analyser la résilience urbaine sur un long pas de temps, mettant en avant des capacités proactives que le système urbain doit développer de façon à (ré) agir face à l’inondation. Ce travail s’est appuyé sur un partenariat socio-économique avec la Ville d’Avignon et son Service SIG (Système d’Information Géographique). L’approche a permis de construire trois indicateurs de mesure afin d’aborder la résilience urbaine, technique et social. Ces indicateurs ont permis d’acquérir des informations sur les variables définissant des potentiels de résilience qui favoriseraient l’émergence d’une réponse adéquate face à une inondation urbaine. L’utilisation de techniques de géovisualisation a permis de favoriser la visualisation des traitements et des résultats afin d’expliciter la démarche auprès des gestionnaires urbains. Parallèlement, des ateliers de concertation ont été montés afin de présenter et discuter des résultats obtenus grâce aux indicateurs avec les responsables et gestionnaires des infrastructures critiques.La co-construction de ces indicateurs, afin de construire une analyse et une connaissance autour de la résilience urbaine, suivis de la mise en place d’ateliers avec les acteurs du territoire, afin de favoriser le processus décisionnel territorial, a permis de développer une culture de résilience. Ce système spatial d’aide à la décision a donc permis la mutualisation des connaissances théoriques et pratiques autour des questions de risques urbains et de résilience afin de parvenir à un consensus nécessaire pour la prise de décision et l’opérationnalisation de la résilienceIn a context of climate change, increased urban flooding and increased uncertainty, urbanmanagers are forced to innovate to design appropriate risk management strategies. Among thesestrategies, making cities resilient has become an imperative. The concept of resilience is amultidisciplinary concept that defines the ability of a system to absorb a disturbance and then recoverits functions. This concept refers to technical, urban, social, architectural, architectural, economic andpolitical innovation and calls into question traditional risk management systems. This injunction toinnovation is perfectly adapted to the urban, economic, political, social and ecological complexity ofthe contemporary world. As a result, the concept of resilience is integrated with urban sprawl issues andassociated risks. However, despite this theoretical and conceptual adequacy, resilience remains complexto integrate into the practices of urban planners and territorial actors. Its multitude of definitions andapproaches have contributed to its abstraction and lack of operationalization.In response to this observation, this research aims to address these operational gaps by buildinga spatial decision support system to clarify and promote the integration of the concept into urbanpractices. The idea behind this approach is that urban resilience embodies the abilities and capacities ofa city and its population to develop before, during and after a disruptive event in order to limit itsnegative impacts. This scientific positioning therefore makes it possible to analyze urban resilience as acontinuum, highlighting proactive capacities that the urban system must develop in order to (re)act inthe face of flooding. This work was based on a socio-economic partnership with the City of Avignonand its GIS Service (Geographic Information System). The approach made it possible to build threemeasurement indicators to address the urban, technical and social resilience of the Avignon area. Theseindicators have made it possible to acquire information on the variables defining potential resilience thatwould foster the emergence of an adequate response to a natural disaster and more precisely to an urbanflood. The use of geovisualization techniques has made it possible to visualize treatments and results inorder to explain the approach to urban managers. At the same time, consultation workshops were heldto present and discuss the results obtained through the indicators with critical infrastructure managersand managers.The co-construction of these indicators, in order to build an analysis and knowledge aroundurban resilience, followed by the implementation of workshops with stakeholders in the territory, inorder to promote the territorial decision-making process, has made it possible to develop a culture ofresilience. This spatial decision support system has therefore made it possible to pool theoretical andpractical knowledge on urban risk and resilience issues in order to reach the consensus necessary fordecision-making and the operationalization of resilience
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Soares, Livio. "Operating System Techniques for Reducing Processor State Pollution." Thesis, 2012. http://hdl.handle.net/1807/32895.
Повний текст джерелаАнотація:
Application performance on modern processors has become increasingly dictated by the use of on-chip structures, such as caches and look-aside buffers. The hierarchical (multi-leveled) design of processor structures, the ubiquity of multicore processor architectures, as well as the increasing
relative cost of accessing memory have all contributed to this condition. Our thesis is that operating systems should provide services and mechanisms for applications to more efficiently utilize on-chip processor structures. As such, this dissertation demonstrates how the operating system can
improve processor efficiency of applications through specific techniques.
Two operating system services are investigated: (1) improving secondary and last-level cache utilization through a run-time cache filtering technique, and (2) improving the processor efficiency of system intensive applications through a new exception-less system call mechanism. With the first mechanism, we introduce the concept of a software pollute buffer and show that it can be used effectively at run-time, with assistance from commodity hardware performance counters, to reduce pollution of secondary on-chip caches.
In the second mechanism, we are able to decouple application and operating system execution, showing the benefits of the reduced interference in various processor components such as the first level instruction and data caches, second level caches and branch predictor. We show that exception-less system calls are particularly effective on modern multicore processors. We explore two ways for applications to use exception-less system calls. The first way, which is completely transparent to the application, uses multi-threading to hide asynchronous communication between the operating system kernel and the application. In the second way, we propose that applications can directly use the exception-less system call interface by designing programs that follow an event-driven architecture.
Книги з теми "Operating system redundancy techniques"
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Somerson, Paul. PC magazine DOS power tools: Techniques, tricks, and utilities. 2nd ed. Toronto: Bantam Books, 1990.
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1964-, Marks Evan R., ed. Solaris solutions for system administrators: Time-saving tips, techniques, and workarounds. New York: John Wiley & Sons, 2000.
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Merusi, Donald M. Survey of operating system techniques: VMS,Unix,OS/2 and MS DOS. Hemel Hempstead: Prentice-Hall, 1992.
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Townsend, Carl. Advanced MS-DOS: Expert techniques for programmers. Indianapolis, Ind., USA: H.W. Sams, 1989.
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United States. National Aeronautics and Space Administration., ed. Software manual for operating particle displacement tracking data acquisition and reduction system. [Washington, DC]: National Aeronautics and Space Administration, 1991.
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DOS power tools: Techniques, tricks, and utilities. 2nd ed. Toronto: Bantam Books, 1990.
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DOS power tools: Techniques, tricks, and utilities. 2nd ed. Toronto: Bantam Books, 1991.
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Introducing PC-DOS and MS-DOS: A guide for beginning and advanced techniques. New York: McGraw-Hill, 1985.
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M, Goodman John. DOS 6.0 power tools: Techniques, tricks, and utilities. New York: Bantam Books, 1993.
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Red Hat Enterprise Linux troubleshooting guide: Identify, capture, and resolve common issues faced by Red Hat Enterprise Linux administrators using best practices and advanced troubleshooting techniques. Birmingham, UK: Packt Publishing, 2015.
Знайти повний текст джерелаЧастини книг з теми "Operating system redundancy techniques"
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Kühn, Johannes Maximilian, Oliver Bringmann, and Wolfgang Rosenstiel. "Increasing Reliability Using Adaptive Cross-Layer Techniques in DRPs: Just-Safe-Enough Responses to Reliability Threats." In Dependable Embedded Systems, 121–38. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-52017-5_5.
Повний текст джерелаАнотація:
AbstractThe developments in the semiconductor industry as predicted by institutions such as the ITRS present a difficult question to hardware and software developers alike: How to implement increasingly complex, power hungry, and critical applications reliably in today’s and tomorrow’s semiconductor technology? The present trend of semiconductor technology is characterized by a sharp increase in complexity, cost, and delicacy. Also, it does not scale along the demands which are still based on and often exceed Moore’s Law. In this chapter, we propose to exploit the architectural redundancies provided by potent, yet energy efficient massively parallel architectures, modeled using Dynamically Reconfigurable Processors (DRP). Using DRPs, we built an extensive cross-layer approach, offering different levels of reliability measures to operating system (OS) and software developers through low-cost hardware redundancy schemes and appropriate physical operating condition tuning. On the hardware side, online testing schemes and error detection are deployed to trigger dynamic remapping to avoid the usage of faulty components. This approach is further complemented through hardware health monitoring that can detect reliability issues such as negative bias temperature instability (NBTI) or hot carrier injection (HCI) before they surface as an error as well as further tuning of operating conditions to delay such phenomena from surfacing.
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David, Francis M., Jeffrey C. Carlyle, Ellick M. Chan, David K. Raila, and Roy H. Campbell. "Exception Handling in the Choices Operating System." In Advanced Topics in Exception Handling Techniques, 42–61. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/11818502_3.
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Kuusela, Jaakko, and Harri Tuominen. "Aspect-Oriented Approach to Operating System Development Empirical Study." In Advanced Techniques in Computing Sciences and Software Engineering, 233–38. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-90-481-3660-5_39.
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Cheng, Xiaohui, and Haodong Tang. "Dynamic Memory Allocation of Embedded Real-Time Operating System Based on TLSF." In Applications and Techniques in Information Security, 29–39. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-2907-4_3.
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Sinha, Amit, and Anantha P. Chandrakasan. "Operating System and Algorithmic Techniques for Energy Scalable Wireless Sensor Networks." In Mobile Data Management, 199–209. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/3-540-44498-x_16.
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Helmy*, Tarek, Anifowose Fatai, and El-Sayed Sallam. "An Efficient Randomized Algorithm for Real-Time Process Scheduling in PicOS Operating System." In Advanced Techniques in Computing Sciences and Software Engineering, 117–22. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-90-481-3660-5_20.
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Marwedel, Peter. "System Software." In Embedded Systems, 203–37. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-60910-8_4.
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AbstractIn order to cope with the complexity of applications of embedded systems, reuse of components is a key technique. As pointed out by Sangiovanni-Vincentelli (The context for platform-based design. IEEE Design and Test of Computers, 2002), software and hardware components must be reused in the platform-based design methosdology (see p. 296). These components comprise knowledge from earlier design efforts and constitute intellectual property (IP). Standard software components that can be reused include system software components such as embedded operating systems (OSs) and middleware. The last term denotes software that provides an intermediate layer between the OS and application software. This chapter starts with a description of general requirements for embedded operating systems. This includes real-time capabilities as well as adaptation techniques to provide just the required functionality. Mutually exclusive access to resources can result in priority inversion, which is a serious problem for real-time systems. Priority inversion can be circumvented with resource access protocols. We will present three such protocols: the priority inheritance, priority ceiling, and stack resource protocols. A separate section covers the ERIKA real-time system kernel. Furthermore, we will explain how Linux can be adapted to systems with tight resource constraints. Finally, we will provide pointers for additional reusable software components, like hardware abstraction layers (HALs), communication software, and real-time data bases. Our description of embedded operating systems and of middleware in this chapter is consistent with the overall design flow.
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Hammer, D. K. "Synchronization Techniques, Illustrated by the Concepts of the Dependable Distributed Operating System DEDOS." In Real Time Computing, 83–110. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-642-88049-0_6.
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Lv, Bo, and Hongbin Wang. "The Techniques of Eye Movement Operating System Based on Human Eye Movements Characteristics." In Frontiers in Computer Education, 949–56. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-27552-4_124.
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Demircan, Cihan, Ali Keçebaş, and Hilmi Cenk Bayrakçı. "Artificial Bee Colony-Based GMPPT for Non-homogeneous Operating Conditions in a Bifacial CPVT System." In Modern Maximum Power Point Tracking Techniques for Photovoltaic Energy Systems, 331–53. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-05578-3_12.
Повний текст джерелаТези доповідей конференцій з теми "Operating system redundancy techniques"
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Adams, George, and Fernando Ferrante. "Markov Modeling Application to a Redundant Safety System." In ASME 2007 Power Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/power2007-22119.
Повний текст джерелаАнотація:
Redundancy of components and subsystems is part of the design of reliable complex engineering systems used in several industrial applications, including power generation facilities. Such engineering systems may be in one or more intermediate operating states at various times. For example, these systems could continue operating during the repair of failed components and during maintenance intervals. For this reason, they do not lend themselves well to traditional reliability modeling techniques that do not account for a system’s progression through various intermediate states. The use of traditional reliability modeling techniques may lead to significantly different estimates of the performance of a complex system required to exhibit high reliability. This paper discusses the application of a Markov modeling approach for the development of reliability estimates of complex engineering systems. This approach is expected to have advantages for modeling reliability for such systems, since they are commonly comprised of redundant sets of components and require a strict set of maintenance operations to ensure their reliability.
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Simani, S., P. R. Spina, S. Beghelli, R. Bettocchi, and C. Fantuzzi. "Fault Detection and Isolation Based on Dynamic Observers Applied to Gas Turbine Control Sensors." In ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/98-gt-158.
Повний текст джерелаАнотація:
In order to prevent machine malfunctions and to determine the machine operating state, it is necessary to use correct measurements from actual system inputs and outputs. This requires the use of techniques for the detection and isolation of sensor faults. In this paper an approach based on analytical redundancy which uses dynamic observers is suggested to solve the sensor fault detection and isolation problem for a single-shaft industrial gas turbine. The proposed technique requires the generation of classical residual functions obtained with different observer configurations. The diagnosis is performed by checking fluctuations of these residuals caused by faults.
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Wrock, Michael R., and Scott B. Nokleby. "Command Strategies for Tele-Operation of Mobile-Manipulator Systems via a Haptic Input Device." In ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/detc2011-47747.
Повний текст джерелаАнотація:
Tele-operation of mobile-manipulator systems (MMS) is typically done by modeling both the manipulator and mobile base as a single system combined with the use of various redundancy resolution techniques to achieve coordinated motion. In this work, the Omnibot MMS is controlled by a 3-DOF (degrees-of-freedom) haptic joystick. The base is a holonomic platform having 3-DOF supporting a 3-DOF manipulator capable of position control within its workspace. By controlling the base and manipulator individually, redundancy resolution techniques are not required because the master has equal DOF to the device it is controlling at any given time. Two command strategies are proposed herein for automatic switching of control between the manipulator and base. The first command strategy is a virtual wall method that uses haptic forces to make the operator feel like they are pushing against a wall at the edge of the manipulator’s workspace, resulting in the base moving. The second command strategy is a two state approach in which each state controls a different device and switching between the two is done by breaking through the workspace limits. With the help of haptic forces, the operator has the sensation of breaking through a compliant surface when switching states. The two proposed strategies were implemented and tested on the Omnibot MMS and both subjective and objective data was used to evaluate and compare the two methods.
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Merrington, Graeme, Oh-Kyu Kwon, Graham Goodwin, and Bengt Carlsson. "Fault Detection and Diagnosis in Gas Turbines." In ASME 1990 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1990. http://dx.doi.org/10.1115/90-gt-339.
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Modern military aircraft are fitted with Engine Monitoring Systems (EMS) which have the potential to provide maintenance personnel with valuable information for diagnosing engine faults and assessing engine condition. In this study, analytical redundancy methods have been applied to gas turbine engine transient data with the view to extracting the desired fault information. The basic idea is to use mathematical models to interrelate the measured variables and then monitor the effects of fault conditions on the new estimates of the model parameters. In most of the existing literature the models used are assumed to be perfect with the primary source of error arising from the measurement noise. In the technique to be described, a new method of quantifying the effects of changes in the operating conditions is presented when simplified models are employed. The technique accounts for undermodelling effects and errors arising from linearization of an inherently nonlinear system. Results obtained show a marked improvement over those obtained with traditional methods.
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Bettocchi, R., P. R. Spina, and P. M. Azzoni. "Fault Detection for Gas Turbine Sensors Using I/O Dynamic Linear Models: Methodology of Fault Code Generation." In ASME 1996 Turbo Asia Conference. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-ta-002.
Повний текст джерелаАнотація:
This paper presents a methodology of sensor diagnosis which appears to be particularly suitable also for application in the field of small/medium power size industrial gas turbines. The methodology is based on the Analytical Redundancy technique and uses ARX (Auto Regressive with eXternal input) MISO (Multi-Input/Single-Output) linear dynamic models obtained from time series data of the gas turbine operating condition. The linear models allow the on-line calculation of some measurable parameter starting from the values of other measured parameters. The comparison between computed and measured values of the same parameters allows setting-up a vector of residuals which, if compared with the columns of the fault matrix, permits the identification of a possible sensor fault. The initial applications of the methodology to a single-shaft industrial gas turbine show an unambiguous and certain detection and isolation of fault in sensors used both in the measurement only and in feedback by the machine control system.
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Libeyre, François, Francis Bainier, and Pascal Alas. "A Comprehensive Modeling of Centrifugal Compressor Vibrations for Early Fault Detection." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-15641.
Повний текст джерелаАнотація:
Abstract In the last decade, the development of machine connectivity has made possible early fault detection with remote analysis of operating data. Solutions aiming to reduce maintenance costs and production losses due to unplanned downtimes were brought to market. These solutions provide with a model of the equipment in healthy conditions using machine learning techniques applied on historical data. During operation a warning is issued when expected and actual measurements do not match. Although these solutions have proven their value to detect abnormal behaviors, they generate a large number of alarms that require resource to be analyzed. Moreover, these solutions rely on a large number of sensors that need to work correctly both for the learning and the monitoring phase. This generates additional maintenance even though these sensors are often not essential to operate the machine. Lastly the solutions are expensive: their application is usually limited to critical machines with risks of production loss. Indeed, they are not economic for a Transmission System Operator that has ensured the availability of its network with redundancy. The objective of the authors was to focus on the monitoring of radial vibrations of centrifugal compressors. Experience proves this is one of the most critical data for early fault detection. The goal was to develop a smart modelling based on historical data using essential parameters influencing rotor-dynamics. As a result, a clear correlation was found between the operating point and the vibration level. That can be easily shown on a centrifugal compressor map. A second-degree polynomial equation was successfully tested. The model equation relies only on two compressor physics parameters: flow coefficient and speed. We discuss in the paper the impact of other essential parameters. The method has been applied on different type of centrifugal compressors, with different bearing technology (magnetic...) or shaft driving equipment (gas turbine, electric motor drive). A fault detection case study using this method is described, eg: vibration variation due to abnormal opening of an anti-surge control valve. In conclusion this method is a simple alternative to usual condition monitoring solutions. Similarly to what was described in the GT2014-25242 for a Predictive Emission Monitoring System [1], equations based on physical parameters prove to be an efficient modelling technique. Moreover, it helps monitoring teams to better understand the underlying relation between parameters. Indeed, to achieve a complete monitoring of a centrifugal compressor health, this method can be combined with first-principle performance models that use the same physical parameters.
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Abu Shernta, Samira, and Ali A. Tamtum. "Using Triple Modular Redundant (TMR) Technique in Critical Systems Operation." In The First Conference for Engineering Sciences and Technology. AIJR Publisher, 2018. http://dx.doi.org/10.21467/proceedings.2.7.
Повний текст джерела
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Askari, Vahid. "Automated Operation With Redundant Ultrasonic Reactor Water Level Monitoring System." In 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-75162.
Повний текст джерелаАнотація:
The proposed ultrasonic Reactor water Level Monitoring system is intended for monitoring water level in the hot leg of a nuclear reactor during Operation at Reduced Inventory (ORI) with the core in place as may be needed for certain maintenance activities. Since the existing fuel bundles continue the production of heat thorough the decay process, it is critical to maintain a certain water flow rate through the reactor. The Residual Heat Removal System (RHRS) handles this task during the reactor shutdown. The free water surface during ORI subjects the RHRS to the risk of air intake. Such an event would trigger a set of emergency procedures for priming the RHRS and bringing it back online. Some of the possible outcomes of such an event are: extension of outage, handling of the extra regulatory reporting tasks, potential requirements for extra testing after system recovery, possible damage to RHR pump, boiling of reactor water, generation of airborne contamination, and fuel damage. Another risk during ORI is reactor overflow. The major immediate concern is the safety of personnel in case of accidental overflow. This event could result in contamination and the related outage delays. The previously existing systems have always had problems with transducer reliability. This has lead to the need for removal and re-installation of their transducers from outage to outage. However, the proposed system uses a redundant design with permanently mounted transducers. The system uses advanced digital signal processing techniques to determine the water level.
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Zhou, Taotao, Enrique López Droguett, and Mohammad Modarres. "A Hybrid Probabilistic Physics of Failure Pattern Recognition Based Approach for Assessment of Multi-Unit Causal Dependencies." In 2016 24th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icone24-61017.
Повний текст джерелаАнотація:
The recent dependencies studies have mainly been done in context of single unit, which means the failures involving components in different units are not explicitly treated. The major scopes are also limited to the simultaneous failures as the direct results of shared causes, namely the Common Cause Failures (CCFs). The causal relations among components or units are rarely addressed. Thus it’s the prime topic of this investigation that the dependencies among multiple units co-located at a site which is called multi-unit dependencies. This paper seeks to propose a hybrid approach by combining physics-based models and supervised learning techniques. The essential idea is to account for the multi-unit dependencies by explicitly modeling the interactions of the underlying physical failure mechanisms. Ultimately a hybrid Dynamic Bayesian Belief Network is developed to model the possible dependencies, and supervised learning techniques are adopted to quantify the likelihood of failures due to dependency effects. Furthermore, an experiment has been designed and presented involving redundant pumping system, the performance of which are monitored by an advanced sensing system. The experiment is now operating and the gathered multi-sensor data will be used to illustrate the proposed approach as the next stage of this research. These sensor data should be of good quality to allow revealing the underlying failure behavior and dependent failures. This study provides an understanding of the inherent risk significance of dependencies among multiple units, and can also work as the basis for the reliability of multi-unit systems where causal dependencies play a relevant role.
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Zaliskyi, Maksym, Oleksandr Solomentsev, Oleksiy Zuiev, Maksim Pavlenko, Iryna Zakharchenko, and Yuliia Petrova. "Data Processing for Analysis of Deteriorating Radio System with Redundancy." In 2021 IEEE Microwave Theory and Techniques in Wireless Communications (MTTW). IEEE, 2021. http://dx.doi.org/10.1109/mttw53539.2021.9607299.
Повний текст джерелаЗвіти організацій з теми "Operating system redundancy techniques"
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Linker, Raphael, Murat Kacira, Avraham Arbel, Gene Giacomelli, and Chieri Kubota. Enhanced Climate Control of Semi-arid and Arid Greenhouses Equipped with Fogging Systems. United States Department of Agriculture, March 2012. http://dx.doi.org/10.32747/2012.7593383.bard.
Повний текст джерелаАнотація:
The main objectives were (1) to develop, implement and validate control procedures that would make it possible to maintain year-round air temperature and humidity at levels suitable for crop cultivation in greenhouses operating in arid and semi-arid regions and (2) to investigate the influence of the operational flexibility of the fogging system on the performance of the system. With respect to the development of climate controllers, we developed a new control approach according to which ventilation is used to maintain the enthalpy of the greenhouse air and fogging is used to adjust the humidity ratio inside the greenhouse. This approach is suitable mostly for greenhouses equipped with mechanized ventilation, and in which the air exchange rate can be controlled with enough confidence. The development and initial validation of the controllers were performed in a small experimental greenhouses located at the Agricultural Research Organization and very good tracking were obtained for both air temperature and relative humidity (maximum mean deviations over a 10-min period with constant setpoints lower than 2.5oC and 5% relative humidity). The robust design approach used to develop the controllers made it possible to transfer successfully these controllers to a much larger semi-commercial greenhouse located in the much drier Arava region. After only minimal adjustments, which did not require lengthy dedicated experiments, satisfactory tracking of the temperature and humidity was achieved, with standard deviation of the tracking error lower than 1oC and 5% for temperature and relative humidity, respectively. These results should help promote the acceptance of modern techniques for designing greenhouse climate controllers, especially since given the large variety of greenhouse structures (shape, size, crop system), developing high performance site-specific controllers for each greenhouse is not feasible. In parallel to this work, a new cooling control strategy, which considers the contribution of humidification and cooling from the crop, was developed for greenhouses equipped with natural ventilation. Prior to the development of the cooling strategy itself, three evapotranspiration models were compared in terms of accuracy and reliability. The cooling strategy that has been developed controls the amount of fog introduced into the greenhouse as well as the percentage of vent openings based on the desired vapor pressure deficit (VPD) and enthalpy, respectively. Numerical simulations were used to compare the performance of the new strategy with a constant fogging rate strategy based on VPD, and on average, the new strategy saved 36% water and consumed 30% less electric energy. In addition, smaller air temperature and relative humidity fluctuations were achieved when using the new strategy. Finally, it was demonstrated that dynamically varying the fog rate and properly selecting the number of nozzles, yields additional water and electricity savings.
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Tire Experimental Characterization Using Contactless Measurement Methods. SAE International, August 2021. http://dx.doi.org/10.4271/2021-01-1114.
Повний текст джерелаАнотація:
In the frame of automotive Noise Vibration and Harshness (NVH) evaluation, inner cabin noise is among the most important indicators. The main noise contributors can be identified in engine, suspensions, tires, powertrain, brake system, etc. With the advent of E-vehicles and the consequent absence of the Internal Combustion Engine (ICE), tire/road noise has gained more importance, particularly at mid-speed driving and in the spectrum up to 300 Hz. At the state of the art, the identification and characterization of Noise and Vibration sources rely on pointwise sensors (microphones, accelerometers, strain gauges). Optical methods such as Digital Image Correlation (DIC) and Laser Doppler Vibrometer (LDV) have recently received special attention in the NVH field because they can be used to obtain full-field measurements. Moreover, these same techniques could also allow to characterize the tire behavior in operating conditions, which would be practically impossible to derive with standard techniques. In this paper we will demonstrate how non-contact full-field measurement techniques can be used to reliably and robustly characterize the tire behavior up to 300 Hz, focusing on static conditions. Experimental modal analysis will extract the modal characteristic of the tire in both free-free and statically preloaded boundary conditions, using both DIC and LDV. The extracted natural frequencies, damping ratios and full-field mode shapes will be used on one side to improve the accuracy of tire models (either by deriving FRF based models or updating FE ones) but also as a reference for future investigation on the tire behavior characterization in rotating conditions.