Hybrid Redundancy Research Articles

Reliability improvement of the dredging perception system: A sensor fault-tolerant strategy

In the dredging industry, the automation and accuracy of the Dredging Perception System (DPS) are vital for operational efficiency and environmental safety. Current DPS implementations face challenges with sensor fault tolerance, leading to system unreliability and increased false alarm rates that can disrupt dredging operations. We propose a Hybrid Redundancy Sensor Fault Tolerance (HRSFT) strategy that integrates matching physical sensors (PS) with two distinct types of virtual sensors (VS) driven by multi-sensor association and time-series prediction models. The HRSFT employs a voting-cold storage strategy to address the false alarm issues commonly associated with single virtual sensor systems. Through experimental validation, the HRSFT strategy has demonstrated its capability to provide accurate replacement information during both single and multi-sensor failure scenarios, effectively managing abnormal sensor data and enhancing the operational reliability of the DPS. The implementation of the HRSFT strategy significantly improves the accuracy and stability of the DPS, suggesting a substantial advancement in sensor fault tolerance that could be applied to similar systems in various industries, leading to safer and more reliable operations.

Predictive Hybrid Redundancy for Aircraft Wheel Braking System - A Design Study

Aircraft brake system plays an important role in safe take-off and landing phases of flight. In order to meet safety requirements, regulatory guidelines like ARP 4761 suggest duo duplex architecture for the aircraft Wheel Braking System (WBS). Safe and efficient braking systems for ground-based vehicles in the name of Brake By Wire (BBW) are also becoming very common resulting in significant research activity in the recent past. In order to reduce number of hardware components and to improve reliability further of BBW systems, Kim and team of Korean university came up with introduction of analytical redundancy for measurement of wheel angular velocity sensors. The scheme involves Predictive Hybrid Redundancy (PHR) for fault detection using a double exponential smoothing method. Since, such systems are not readily suitable for aircraft WBS, the present study is an attempt to extend this approach to aircraft WBS with appropriate modifications to integrate with normal mode, standby mode and emergency modes of aircraft WBS. Simulation studies for synthetic sensor signals show possibility of continued operation, with one sensor being operational, in the presence of transient, intermittent and hard over faults.

A cost-efficient hybrid redundancy coding scheme for wireless storage systems

With distributed storage technique becoming a promising technology for storing massive data in wireless environment, how to improve the reliability of the storage systems has become the focus of researchers. As a redundancy scheme, the erasure coding has been widely used because of its high fault tolerance and low storage overhead performance. However, a large amount of repair overhead consumed to reconstruct lost data has become the most significant issue in erasure-coded storage systems. In this paper, a wireless heterogeneous storage network with two-layer is designed, where processing units and storage nodes communicate cooperatively. Furthermore, with the consideration of the access frequency skew of stored information and the performance difference of storage nodes, we propose a novel repairable fountain code scheme based on partial duplication technique (PD-RFC), which can modify the repair bandwidth and improve the availability of links between nodes without almost increasing additional storage space overhead. Furthermore, a hybrid code scheme combined by PD-RFC scheme and RFC scheme is designed for the heterogeneous two-layer storage network. The simulation results have shown that the hybrid scheme significantly outperforms other redundant schemes in energy communication cost saving.

Effects of ecological factors on phenolic compounds in Salvia multicaulis Vahl (Lamiaceae)

This study aimed to assess the impact of certain climatic factors and soil elements on principal phenolic compounds in Salvia multicaulis (S. multicaulis). For this purpose, the association between the environmental factors and phenolic compounds in the samples was analysed consecutively using the hybrid redundancy analysis (hRDA), correlation, and path analyses. Based on hRDA, the climatic factors were the major environmental factors influencing total phenolics (YTPhen) and total flavonoids (YTFlav) contents, but phenolic acids were affected by both climatic factors and the soil elements. In path analysis, the average April–May daily minimum temperature (XAp-MaMinT) negatively affected YTPhen (path coefficient of −0.524). The average April–May daily relative humidity (XAp-MaRH) was the key climatic factor promoting (0.609) YTFlav. April–May cumulative precipitation (XAp-MaPr) and the soil sodium content (XNa) were the determinant factors negatively affecting (−0.405 and −0.388, respectively) rosmarinic acid content (YRosA). XAp-MaRH and the soil pH (XpH) were the most effective factors influencing (0.465 and −0.498, respectively) caffeic acid content (YCafA). The soil magnesium (XMg) was the only environmental factor reducing (−0.483) the chlorogenic acid content (YChlA). These findings could aid sit specific exploration of the plants with a high yield of specific phytochemicals demanded by the food and pharmaceutical industries.

A hybrid redundancy scheme for medium‐voltage three‐phase cascaded H‐bridge electronic power transformer

A hybrid redundancy (HR) scheme is proposed for the medium-voltage three-phase cascaded H-bridge electronic power transformer (CHB-EPT) based on the combination of the global redundant power modules and local redundant power modules. A “HOT-FIRST-LOCAL-FIRST” transition strategy is designed to achieve a short transition time. Furthermore, to reduce the power loss of the redundant power modules, an intermittent charging (IC) strategy is proposed for the hot-reserved redundant power modules. The detailed analysis of the topology shows that the proposed scheme can achieve low cost, high reliability, low power loss, and good transition performance. The performances are verified by simulations and experimental results.

Research on Hybrid Redundancy Voting Algorithm Based on Fuzzy Theory

The hardware redundancy technology is to reduce the basic reliability in exchange for the high reliability and safety of the system, but the failure rate of the system will increase with the increase of the hardware redundancy. Aiming at the disadvantages of hardware redundancy, the article takes the angle of attack(AOA) as the object, and constructs the analytical value of AOA based on the analytical relationship between the sensors of the flight control system; Introduce an equalization algorithm to eliminate the drift error between redundant signals, further proposes a hybrid redundancy voting algorithm based on hardware redundancy and analysis redundancy. The algorithm calculates the weight of the sensor signal based on the difference between the sensor signal and the analytical value, so that the voting value is closer to the true value, thereby improving the safety of the system. At the end of the article, the feasibility of the voting algorithm is verified by simulation; the analytical study of the AOA proves the effectiveness of the hybrid redundancy design scheme and the voting algorithm.

A simple hybrid redundancy strategy accompanied by simplified swarm optimization for the reliability–redundancy allocation problem

In this study, a new strategic model called Markov-based cold standby combined with components mixing (RRAP-CM-MCCS), is proposed to improve system reliability. The optimization method used here is simplified swarm optimization (SSO), in which SSO adopts a multi-role resource sharing strategy to provide the diverse system components required by RRAP-CM-MCCS. The diversity here lies in providing every component in a subsystem with its own failure rate as a decision variable in addition to determining the corresponding reliability of each component. Consequently, compared to the state-of-the-art results in the literature, not only can the system reliability be improved, but the combination of multiple configurations also enables relevant required resources to be saved.

Novel modified memory built in self‐repair (MMBISR) for SRAM using hybrid redundancy‐analysis technique

The article presents a new augmented and improved MMBISR for SRAM using hybrid redundancy analysis (HRA). The presented algorithm is the augmented version of essential spare pivoting (ESP) and local repair most (LRM). The algorithm proposes the best solution by providing optimised set of row and column combination which were suitable for the repairing process. In the proposed redundancy analysis (RA) algorithm, the fault dictionary can be updated or fixed concurrently, according to MBIST needs and supplied control signals. The row and column pivots and repair requests are also serviced according to precedency list prepared by the comparing actions. The comparative analysis with LRM and ESP-RA algorithms shows that the proposed algorithm has reduced complexity and tracing time in terms of implementation and in terms of finding row and column pivots. For the implementation, a MBISR hardware structure is designed and tested using suitable VHDL descriptions that were targeted for Virtex-5, xc5vlx30 FPGA. The results were also justified that the proposed algorithm is quite effective as the repair rate is increased up to 4% compared to the ESP. However, some nominal area penalty is observed as compared to ESP.

INVESTIGATION OF A HYBRID REDUNDANCY IN THE FAULTTOLERANT SYSTEMS

Context. Structural redundancy is one of the main ways to create highly reliable devices and systems for critical applications. The object of the study was hybrid redundancy in the Fault-Tolerant Systems, for example in aerospace hardware exposed to radiation. Objective. The goal of the work is the calculation of the complexity and probability of failure-free operation of digital circuits with hybrid redundancy combining tripling, deep tripling, and quadding. The comparison shows that tripling is not always better than a circuit without redundancy over a sufficiently large time interval. Good results are obtained by tripling with three majority voters and deep tripling, but the latter significantly increases the time delay of the signal. The greatest gain in reliability provides quadding at the transistors level, but it is not always possible due to the restrictions of Mead-Conway, in addition, the delay at least is doubled. The article describes proposed method of the combined redundancy taking into account the necessary hardware costs and time delay. Method. Determining the complexity in the units of the conditional number of transistors and maximum signal path from the input to the output in the number of transistors, as well as using the Weibull distribution to estimate the probability of failure-free operation. Simulation of proposed hybrid redundancy in the system NI Multisim by National Instruments Electronics Workbench Group. The failure-free operation probability estimation in the computer mathematics system MathCad. Results. Expressions are obtained for the estimates of complexity, time delay and probability of failure-free operation of redundant digital circuits; curves are built in the Mathcad. Simulation confirms the performance of the proposed redundancy options. Conclusions. The conducted studies allowed us to establish the effectiveness of hybrid redundancy to improve the reliability and the radiation resistance of the digital circuits.

Designing and Evaluating Redundancy-Based Soft-Error Masking on a Continuum of Energy versus Robustness

Near-threshold computing is an effective strategy to reduce the power dissipation of deeply-scaled CMOS logic circuits. However, near-threshold strategies exacerbate the impact of delay variations on device performance and increase the susceptibility to soft errors due to narrow voltage margins. The objective of this work is to develop and assess design approaches that leverage tradeoffs between performance and the resilience of fault masking coverage for various soft-error mitigation techniques. The primary insight from this work is identification of redundancy-based hardening techniques that can deliver increased benefits in terms of the fault coverage energy ratio (FCER) for the leveraged tradeoffs within iso-energy constraints at near-threshold voltage (NTV). Simulation results demonstrate that temporal redundancy approaches offer favorable tradeoffs in terms of FCER. They exhibit reduced impact on performance variations and achieve extensive soft fault masking, therefore improving the system robustness within acceptable delay constraints. Meanwhile, it is shown that a hybrid redundancy approach can be used to protect a low-power system to maintain throughput while tolerating soft errors. We demonstrate how the FCER metric can be used as an optimization parameter to guide circuit synthesis to meet performance and robustness goals. Finally, the impact of design diversity on spatial and hybrid redundancy at NTV is assessed in terms of FCER and delay variation to form overall recommendations regarding soft-error mitigation at NTV.

High Performance and Reliable Fault Detection Scheme for the Secure Hash Algorithm

Background/Objectives: Among the powerful techniques against the protected hash functions (SHA) the method of fault injection attacks. For obtain the confidential information, the method consist to inject this attacks during the process of the hash algorithm. In literature, they proposed a many methods of countermeasures to secure the SHA implementation against these attacks. Methods/Statistical Analysis: In this paper, we proposed a new scheme of fault detection; this scheme is based on the combines of two redundancies named hybrid redundancy for the hash algorithm. The weaknesses and the strengths of our proposed method against the fault attacks are discussed. Findings: our schemes proposed reaches 99.999% fault coverage. Moreover, we are implemented our proposed scheme on Xilinx Virtex-5 and Virtex-II Pro FPGA. Its area overhead fault coverage, frequency and throughput degradation have been compared and it is shown that our proposed scheme allows a trade-off between the security of the SHA and hardware overhead. Application/Improvements: Compared to other work, our fault detection scheme has the important performances in terms of frequency, occupied slices, fault coverage and throughput.

Analytical hybrid redundancy system for the fault tolerance of advanced driver assistance systems

The growing dependence on electronic sensors has resulted in increased concerns over the fault tolerance in safety-critical systems. For example, a vehicle with an advanced driver assistance system, which assists safe driving using numerous electronic elements, should be fault tolerant because sensor failures can lead to events in which car occupants receive serious injuries. However, it is often undesirable to have multiple redundant sensors because of the high cost of critical sensors such as the radar in an advanced driver assistance system. To address this problem, we present an analytical hybrid redundancy system that provides fault tolerance using fault detection and exception-handling algorithms. On the basis of the actual range data from an advanced driver assistance system radar, we present the results of numerical simulations of the analytical hybrid redundancy system and show that it outperforms existing approaches with respect to a number of performance indices.

The respective effects of soil heavy metal fractions by sequential extraction procedure and soil properties on the accumulation of heavy metals in rice grains and brassicas.

This study was carried out to examine heavy metal accumulation in rice grains and brassicas and to identify the different controls, such as soil properties and soil heavy metal fractions obtained by the Community Bureau of Reference (BCR) sequential extraction, in their accumulation. In Guangdong Province, South China, rice grain and brassica samples, along with their rhizospheric soil, were collected from fields on the basis of distance downstream from electroplating factories, whose wastewater was used for irrigation. The results showed that long-term irrigation using the electroplating effluent has not only enriched the rhizospheric soil with Cd, Cr, Cu, and Zn but has also increased their mobility and bioavailability. The average concentrations of Cd and Cr in rice grains and brassicas from closest to the electroplating factories were significantly higher than those from the control areas. Results from hybrid redundancy analysis (hRDA) and redundancy analysis (RDA) showed that the BCR fractions of soil heavy metals could explain 29.0 and 46.5% of total eigenvalue for heavy metal concentrations in rice grains and brassicas, respectively, while soil properties could only explain 11.1 and 33.4%, respectively. This indicated that heavy metal fractions exerted more control upon their concentrations in rice grains and brassicas than soil properties. In terms of metal interaction, an increase of residual Zn in paddy soil or a decrease of acid soluble Cd in the brassica soil could enhance the accumulation of Cd, Cu, Cr, and Pb in both rice grains and brassicas, respectively, while the reducible or oxidizable Cd in soil could enhance the plants' accumulation of Cr and Pb. The RDA showed an inhibition effect of sand content and CFO on the accumulation of heavy metals in rice grains and brassicas. Moreover, multiple stepwise linear regression could offer prediction for Cd, Cu, Cr, and Zn concentrations in the two crops by soil heavy metal fractions and soil properties.

HRSPC: a hybrid redundancy scheme via exploring computational locality to support fast recovery and high reliability in distributed storage systems

Replication and erasure codes are two popular schemes to provide fault tolerance in distributed storage systems. However, they both face some challenges when used in cloud storage. As the scale of data increases and failure becomes common in data centers, replication scheme suffers from high storage cost while erasure codes suffer from performance degradation and network bandwidth cost particularly under faulty conditions. In this paper, we present a novel scheme, named Hybrid Redundancy Scheme Plus Computing, or HRSPC for short, to achieve better performance and storage cost trade-off via exploiting the computational capability of storage nodes and taking advantage of both replication and erasure codes׳ features. It conducts degraded read or recovery with very low I/O cost and network bandwidth while the storage cost is relatively low, and thus to achieve high performance in both normal and faulty conditions. In addition, the reliability of HRSPC is higher than erasure codes and replication under similar configurations.

Innovative soft fault diagnosis method for dual-redundancy sensors

Purpose – This paper aims to conduct soft fault diagnosis of dual-redundancy sensors. An innovative fault diagnosis method, which combines a tracking differentiator and a sequential probability ratio test, is proposed. Design/methodology/approach – First, two tracking differentiators are used to track and predict the two original signals, and determine their residuals. These residuals are used to calculate one quadratic residual. Then, a sequential probability ratio test is carried out on this quadratic residual to obtain log-likelihood ratio. A fault can be detected through comparing the log-likelihood ratio value with the threshold value. Finally, analyses of the difference in the residuals, which locates the fault, and of the difference in the original signals, which reveals the fault level and type, are completed successively. Findings – Results from experimentation show that this method can realise soft fault diagnosis for dual-redundancy sensors. Originality/value – The method proposed in the paper gives a new idea to study hybrid redundancy. The method provides a new application mode for tracking differentiators and sequential probability ratio test. The method can be used in robots, such as unmanned aerial vehicles and unmanned ground vehicles, to improve their fault tolerance. It can also be applied to the key parts of industrial production lines to decrease financial losses caused by sensor faults.

Availability Analysis of Predictive Hybrid M-Out-of-N Systems

In m-out-of-n system, if m-out-of-n modules agree, system can report consensus; otherwise, the system fails. On the other hand, in predictive hybrid system if there is no agreement, a history record of previous successful result(s) is used to predict the output. In order to analyze the availability of predictive hybrid redundancy system, Markov modeling is utilized. By using Markov model of the system in steady state, the availability is derived and compared with m-out-of-n system. The results of simulation demonstrated that the availability of predictive hybrid system is higher than m-out-of-n system especially for large m.

Availability Analysis of Predictive Hybrid M-Out-of-N Systems

In m-out-of-n system, if m-out-of-n modules agree, system can report consensus; otherwise, the system fails. On the other hand, in predictive hybrid system if there is no agreement, a history record of previous successful result(s) is used to predict the output. In order to analyze the availability of predictive hybrid redundancy system, Markov modeling is utilized. By using Markov model of the system in steady state, the availability is derived and compared with m-out-of-n system. The results of simulation demonstrated that the availability of predictive hybrid system is higher than m-out-of-n system especially for large m.

Hybrid redundancy approach to increase the reliability of FPGA based speed controller core for high speed train

With the progress of the railway technology, the railway transportation is becoming more efficient, intelligent and faster. High speed trains, as a major part of the railway transportation, are engaged with passenger’s safety, and therefore the reliability issue is very important in such vital systems. In this paper, a dependable speed controller core based on FPGA has been developed for high speed trains. To improve the reliability and mitigate single upset faults on basic speed controller, this paper proposes a new effective method which is based on hardware redundancy. In the proposed Hybrid Dual Duplex Redundancy (HDDR) method, the original controller is quadruplicated and correct values are voted through the comparator and error detection unit. We have analyzed the proposed system with Reliability, Availability, Mean time to failure and Security (RAMS) theory in order to evaluate the effectiveness of proposed scheme. Theoretical analysis shows that the Mean Time To Failure (MTTF) of the proposed system is 2.5 times better than the traditional Triple Modular Redundancy (TMR). Furthermore, the fault injection experimental results reveal that the capability of tolerating Single Event Upsets (SEUs) in the proposed method increases up to 7.5 times with respect to a regular speed controller.

The Analysis and Research of the Hybir Redundancy Elimination Algorithm (HRRE) Based on RFID Middleware Reader

LEO (Layered Elimination Optimization) algorithm and RRE (Redundant Reader Elimination) algorithm are widely used because of their needless of complicated operations and efficient redundant elimination ability. This study puts forward an improved hybrid redundant elimination algorithm HRRE. By introducing the candidate holder, the maximize redundant-readers and the minimize work readers are guaranteed. At the same time the use of label information in the RFID middleware to identify the reader redundant state reduces the performance effect of the system effectively which is caused by write operation. The power consumption of the system caused by the reader write information to label is also reduced at the same time. The simulation results show that the improved hybrid redundancy elimination algorithm has a good solving effect.

Adaptive fault‐tolerant control based on hybrid redundancy

ABSTRACTThis paper presents a new actuator fault accommodation based on a hybrid of static and dynamic redundancies. Introduction of the activation functions for the actuators makes it possible to switch the redundancy modes appropriately. These functions are switched among the two values, 0 and 1, by monitoring only the input and output signals, and they determine the power supplies for the actuators. Furthermore, in this paper, the adaptively switching high‐gain feedback controller is developed to achieve the λ‐tracking in the presence of unknown perturbations. The adaptive tracker is modified to suit the switching mechanism for tuning the activation‐functions. Thus, the proposed adaptive fault‐tolerant control system with a hybrid redundancy has the advantages of both static and dynamic redundancies, and has high robustness with regard to actuator failures and variations in dynamics. In addition, a practical application to a chemical reactor is shown to confirm the effectiveness of the overall adaptive fault‐tolerant control system. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.