Journal articles: 'Switch failures'

1

Cui, Yunhe, Qing Qian, Guowei Shen, Chun Guo, and Saifei Li. "REVERT: A Network Failure Recovery Method for Data Center Networks." Electronics 9, no. 8 (July 23, 2020): 1187. http://dx.doi.org/10.3390/electronics9081187.

Full text

Abstract:

As a repository that holds computing facilities, storage facilities, network facilities and other facilities, the Software Defined Data Center (SDDC) can provide computing and storage resources for users. For a SDDC, it is important to provide continuous services for users. Hence, in order to achieve high reliability in Software Defined Data Center Networks (SDDCNs), a network failure recovery method for software defined data center networks (REVERT) is proposed to recover failures in SDDCNs. In REVERT, the network failures that occurred in SDDCNs are classified into three types, which are switch failure, failure of links among switches and failure of links between switches and servers. Specially, except recovering the switch failure and failure of links between switches, REVERT can also recover the failures of links between the switches and servers. To achieve that, a failure preprocessing method used to classify the network failures, a data structure for storing and finding the affected flows, a server cluster agent for communicating with the server clustering algorithm and a routing path calculation method are designed in REVERT. Meanwhile, REVERT has been implemented and evaluated on RYU controller and Mininet using three routing algorithms. Compared with the link usage before recovering the network failures, when there are more than 200 flows in the network, the mean link usages only slightly increase at about 1.83 percent. More importantly, the evaluation results also demonstrate that except recovering switch failures, intra-topo link failures, REVERT has the ability of recovering failures of links between servers and edge switches successfully.

APA, Harvard, Vancouver, ISO, and other styles

2

Singh, Rachee, Muqeet Mukhtar, Ashay Krishna, Aniruddha Parkhi, Jitendra Padhye, and David Maltz. "Surviving switch failures in cloud datacenters." ACM SIGCOMM Computer Communication Review 51, no. 2 (April 11, 2021): 2–9. http://dx.doi.org/10.1145/3464994.3464996.

Full text

Abstract:

Switch failures can hamper access to client services, cause link congestion and blackhole network traffic. In this study, we examine the nature of switch failures in the datacenters of a large commercial cloud provider through the lens of survival theory. We study a cohort of over 180,000 switches with a variety of hardware and software configurations and find that datacenter switches have a 98% likelihood of functioning uninterrupted for over 3 months since deployment in production. However, there is significant heterogeneity in switch survival rates with respect to their hardware and software: the switches of one vendor are twice as likely to fail compared to the others. We attribute the majority of switch failures to hardware impairments and unplanned power losses. We find that the in-house switch operating system, SONiC, boosts the survival likelihood of switches in datacenters by 1% by eliminating switch failures caused by software bugs in vendor switch OSes.

APA, Harvard, Vancouver, ISO, and other styles

3

LI, DAWEI, JIE WU, DAJIN WANG, and JIAYIN WANG. "Software-Defined Networking Switches for Fast Single-Link Failure Recovery." Journal of Interconnection Networks 18, no. 04 (December 2018): 1850014. http://dx.doi.org/10.1142/s0219265918500147.

Full text

Abstract:

In this paper, we consider IP fast recovery from single-link failures in a given network topology. The basic idea is to replace some existing routers with a designated switch. When a link fails, the affected router will send all the affected traffic to the designated switch (through pre-configured IP tunnels), which will deliver the affected traffic to its destination without using the failed link. The goal of the approach is to achieve faster failure recovery than traditional routing protocols that employ reactive computing upon link failures. Software-Defined Networking (SDN) switches can serve as the designated switches because they can flexibly redirect affected traffic to other routes, instead of only to the shortest paths in the network. However, SDN switches are very expensive. Our objective is to minimize the number of SDN switches needed and to guarantee that the network can still recover from any single-link failure. For networks with uniform link costs, we show that using normal non-SDN switches with IP tunneling capability as designated switches can guarantee recovery from any single-link failure. For networks with general link costs, we find that not all single-link failures can be recovered by using non-SDN switches as designated switches; by using SDN switches only when necessary, we can reduce the total number of SDN switches needed compared to an existing work. We conduct extensive simulations to verify our proposed approaches.

APA, Harvard, Vancouver, ISO, and other styles

4

Bemment, Samuel D., Roger M. Goodall, Roger Dixon, and Christopher P. Ward. "Improving the reliability and availability of railway track switching by analysing historical failure data and introducing functionally redundant subsystems." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 5 (September 13, 2017): 1407–24. http://dx.doi.org/10.1177/0954409717727879.

Full text

Abstract:

Track switches are safety critical assets that not only provide flexibility to rail networks but also present single points of failure. Switch failures within dense-traffic passenger rail systems cause a disproportionate level of delay. Subsystem redundancy is one of a number of approaches, which can be used to ensure an appropriate safety integrity and/or operational reliability level, successfully adopted by, for example, the aeronautical and nuclear industries. This paper models the adoption of a functional redundancy approach to the functional subsystems of traditional railway track switching arrangements in order to evaluate the potential increase in the reliability and availability of switches. The paper makes three main contributions. First, 2P-Weibull failure distributions for each functional subsystem of each common category of points operating equipment are established using a timeline and iterative maximum likelihood estimation approach, based on almost 40,000 sampled failure events over 74,800 years of continuous operation. Second, these results are used as baselines in a reliability block diagram approach to model engineering fault tolerance, through subsystem redundancy, into existing switching systems. Third, the reliability block diagrams are used with a Monte-Carlo simulation approach in order to model the availability of redundantly engineered track switches over expected asset lifetimes. Results show a significant improvement in the reliability and availability of switches; unscheduled downtime reduces by an order of magnitude across all powered switch types, whilst significant increases in the whole-system reliability are demonstrated. Hence, switch designs utilising a functional redundancy approach are well worth further investigation. However, it is also established that as equipment failures are engineered out, switch reliability/availability can be seen to plateau as the dominant contributor to unreliability becomes human error.

APA, Harvard, Vancouver, ISO, and other styles

5

Gravenstein, Dietrich, Harshdeep Wilkhu, Edwin B. Liem, Stuart Tilman, and Samsun Lampotang. "Aestiva Ventilation Mode Selector Switch Failures." Anesthesia & Analgesia 104, no. 4 (April 2007): 860–62. http://dx.doi.org/10.1213/01.ane.0000256873.96114.48.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Chen, Jue, Jinbang Chen, Junchen Ling, Junlong Zhou, and Wei Zhang. "Link Failure Recovery in SDN: High Efficiency, Strong Scalability and Wide Applicability." Journal of Circuits, Systems and Computers 27, no. 06 (February 22, 2018): 1850087. http://dx.doi.org/10.1142/s0218126618500871.

Full text

Abstract:

Link failures are commonly observed in computer networks, including the newly emerging Software Defined Network (SDN). Considering that failure recovery methods used in traditional networks cannot be applied to SDN networks directly, we propose a method named pro-VLAN in this paper, which calculates a backup path and assigns a unique VLAN id for each link of the network based on the protection mechanism. It makes the most of SDN’s features and can recover a single link failure in SDN with the advantages of high efficiency, strong scalability and wide applicability. More specifically, high efficiency (i.e., a fast failure recovery with a low memory consumption) is achieved by calculating backup paths for each link instead of each flow and using group tables to switch backup paths automatically and locally when failures occur. Strong scalability (i.e., the amount of backup flow entries per switch is stable) is achieved by keeping the amount of links per switch no matter how the network scale extends or how the amount of flows increases. Wide applicability is achieved by always finding a path available without modifying any hardware or protocol as long as the network is still reachable after a link failure. Simulation results and mathematical analysis demonstrate that both pro-VLAN and a flow-based protection method achieve a fast failure recovery, while pro-VLAN consumes less than 1% of the forwarding entries to store backup paths as compared to the flow-based method. Moreover, when the network scale increases from 10 to 60 switches by 500%, the increase of the number of backup flow entries per switch built by pro-VLAN is only less than 50%.

APA, Harvard, Vancouver, ISO, and other styles

7

Kim, Gyuyeong, and Wonjun Lee. "In-network leaderless replication for distributed data stores." Proceedings of the VLDB Endowment 15, no. 7 (March 2022): 1337–49. http://dx.doi.org/10.14778/3523210.3523213.

Full text

Abstract:

Leaderless replication allows any replica to handle any type of request to achieve read scalability and high availability for distributed data stores. However, this entails burdensome coordination overhead of replication protocols, degrading write throughput. In addition, the data store still requires coordination for membership changes, making it hard to resolve server failures quickly. To this end, we present NetLR, a replicated data store architecture that supports high performance, fault tolerance, and linearizability simultaneously. The key idea of NetLR is moving the entire replication functions into the network by leveraging the switch as an on-path in-network replication orchestrator. Specifically, NetLR performs consistency-aware read scheduling, high-performance write coordination, and active fault adaptation in the network switch. Our in-network replication eliminates inter-replica coordination for writes and membership changes, providing high write performance and fast failure handling. NetLR can be implemented using programmable switches at a line rate with only 5.68% of additional memory usage. We implement a prototype of NetLR on an Intel Tofino switch and conduct extensive testbed experiments. Our evaluation results show that NetLR is the only solution that achieves high throughput and low latency and is robust to server failures.

APA, Harvard, Vancouver, ISO, and other styles

8

Kim, Sang-Hun, Seok-Min Kim, Sungmin Park, and Kyo-Beum Lee. "Switch Open-Fault Detection for a Three-Phase Hybrid Active Neutral-Point-Clamped Rectifier." Electronics 9, no. 9 (September 3, 2020): 1437. http://dx.doi.org/10.3390/electronics9091437.

Full text

Abstract:

This paper proposes a fault-detection method for open-switch failures in hybrid active neutral-point-clamped (HANPC) rectifiers. The basic HANPC topology comprises two SiC-based metal-oxide-semiconductor field-effect transistors (MOSFETs) and four Si insulated-gate bipolar transistors (IGBTs). A three-phase rectifier system using the HANPC topology can produce higher efficiency and lower current harmonics. An open-switch fault in a HANPC rectifier can be a MOSFET or IGBT fault. In this work, faulty cases of six different switches are analyzed based on the current distortion in the stationary reference frame. Open faults in MOSFET switches cause immediate and remarkable current distortions, whereas, open faults in IGBT switches are difficult to detect using conventional methods. To detect an IGBT fault, the proposed detection method utilizes some of the reactive power in a certain period to make an important difference, using the direct-quadrant (dq)-axis current information derived from the three-phase current. Thus, the proposed detection method is based on three-phase current measurements and does not use additional hardware. By analyzing the individual characteristics of each switch failure, the failed switch can be located exactly. The effectiveness and feasibility of the proposed fault-detection method are verified through PSIM simulations and experimental results.

APA, Harvard, Vancouver, ISO, and other styles

9

Pearman, Gordon R. "Automatic BusBar Transfer Switch Fault Tree Analysis." Marine Technology and SNAME News 34, no. 01 (January 1, 1997): 31–43. http://dx.doi.org/10.5957/mt1.1997.34.1.31.

Full text

Abstract:

This paper discusses the application of an existing statistical analysis technique called "Fault Tree Analysis " to Automatic BusBar Transfer Switch failures on a new class of Naval Supply Ship. Fault Tree Analysis is a technique, used in many "High Technology Industries, " to pictorially display facts surrounding system, equipment or process failures. Technological complexity and safety concerns in the marine industry make it necessary to also use an organized technique to display facts affecting undesirable events, or failures, and their cause and effect.

APA, Harvard, Vancouver, ISO, and other styles

10

Silvus, Stan. "Failure Analysis of Passive Components." EDFA Technical Articles 1, no. 2 (May 1, 1999): 15–16. http://dx.doi.org/10.31399/asm.edfa.1999-2.p015.

Full text

Abstract:

Abstract This article explains why it has become necessary for equipment builders to analyze passive component failures and how the findings should be reported to manufacturers. It describes the general approach and steps involved in analyzing passive component failures and the methods and equipment used. It also explains how an actual failure involving a microwave switch was resolved.

APA, Harvard, Vancouver, ISO, and other styles

11

Duong, Michel, Marielle Buisson, Gilles Peytavin, Evelyne Kohli, Lionel Piroth, Benoit Martha, Michèle Grappin, Pascal Chavanet, and Henri Portier. "Low Trough Plasma Concentrations of Nevirapine Associated with Virologic Rebounds in HIV-Infected Patients Who Switched from Protease Inhibitors." Annals of Pharmacotherapy 39, no. 4 (April 2005): 603–9. http://dx.doi.org/10.1345/aph.1e563.

Full text

Abstract:

BACKGROUND: The substitution of a nonnucleoside reverse-transcriptase inhibitor (NNRTI) for protease inhibitors (PIs) has demonstrated its suitability to maintain virologic response. However, the switch from PIs to an NNRTI could fail for a number of reasons, including NNRTI-associated toxicity and emergence of NNRTI-resistant variants. OBJECTIVE: To describe the virologic failures among 74 HIV-infected patients who switched from PIs to nevirapine. METHODS: Virologic failure was defined as any rebound of the plasma HIV-RNA (pVL) levels >1000 copies/mL on one occasion or 2 consecutive intermittent viremia episodes defined as increases of the pVL >20 copies/mL but <1000 copies/mL. Virologic failures were investigated retrospectively by determining nevirapine trough concentrations and performing genotypic resistance analysis. RESULTS: The mean nevirapine concentration was significantly lower in patients with virologic failure in comparison with patients with virologic response (2572 ± 1642 vs 4550 ± 2084 ng/mL, respectively; p = 0.003). In multivariate analysis, the mean duration of undetectable pVL before the switch and the mean plasma concentration of nevirapine were significantly associated with virologic success with relative rates of 1.39 (95% CI 1.10 to 1.76, p = 0.006) and 2.7 (95% CI 1.37 to 5.41, p = 0.01), respectively. In patients with pVL >1000 copies/mL, nevirapine mutations and nucleoside reverse-transcriptase inhibitor mutations were found in 80% of the cases. CONCLUSIONS: The risk of virologic failure after the switch from PI to nevirapine is higher in cases of inadequate nevirapine plasma concentrations. Our data support prospective monitoring of nevirapine plasma concentrations to detect low concentrations prior to the emergence of resistance mutations.

APA, Harvard, Vancouver, ISO, and other styles

12

Wasita, Rai Riska Resty, Ni Made Sri Nopiyani, and Pande Putu Januraga. "Switching of primary health care providers among self-paid health insurance participants in Denpasar, Bali, Indonesia." Public Health and Preventive Medicine Archive 6, no. 2 (December 1, 2018): 140. http://dx.doi.org/10.15562/phpma.v6i2.182.

Full text

Abstract:

Background and purposes: The number of Jaminan Kesehatan Nasional or National Health Insurance (NHI) participants switching their fasilitas kesehatan tingkat pertama or primary healthcare (PHC) providers is increasing and dominated by self-paid participants. This switching could result in unequal distribution of NHI participants and amount of capitation among PHC providers. This study aims to explore the reasons underlying self-paid NHI participants to switch PHC providers.Method: This is a qualitative study using in-depth interviews with a total of 14 participants recruited purposively, consisted of ten NHI self-paid participants who had switched and four participants who intend to switch PHC providers. Semi-structured interview guide incorporated the aspects of Consumer Switching Behavior Model. The interviews explored four aspects of participants’ intention to switch providers including inconvenience, service encounter failures, core health service failures, and attraction by competitor. The verbatim transcripts were analyzed thematically.Results: Self-paid NHI participants in this study cited four main reasons for switching PHC providers. The first reason is inconvenience in accessing PHC provider’s services due to long distance, long waiting times, unsuitable opening hours, and poor facilities. Secondly, patients cited the poor interaction between healthcare providers and patients specifically, lack of attentiveness, poor eye contact, poor delivery of health information, lack of consideration of patients’ opinions, and lack of responsiveness to patients’ complaints. The third reason is core healthcare service failures, including hasty examinations, inaccurate diagnoses, and errors in prescribing medication. Finally, informants reported that they wished to switch PHC providers due to the attractiveness of other providers, in terms of facilities availability, professionalism of healthcare providers, additional health programs, and ease of access to fasilitas kesehatan rujukan tingkat lanjut or referral healthcare facilities.Conclusion: Self-paid NHI participants’ intention to switch PHC providers was mainly attributed to the perceived poor healthcare quality of the provider and superiority of the others. Continuous quality improvement should be undertaken by PHC providers to increase participants’ loyalty.

APA, Harvard, Vancouver, ISO, and other styles

13

DAY, KHALED, and ABDEL-ELAH AL-AYYOUB. "ADAPTIVE FAULT-TOLERANT ROUTING IN STAR NETWORKS." Journal of Interconnection Networks 02, no. 02 (June 2001): 213–31. http://dx.doi.org/10.1142/s0219265901000336.

Full text

Abstract:

We take advantage of the hierarchical structure of the star graph network to obtain an efficient method for constructing node-disjoint paths between arbitrary pairs of nodes in the network. A distributed fault-tolerant routing algorithm for the star network based on this construction method is then presented and evaluated. The proposed algorithm adapts the routing decisions in response to node failures. Node failure and repair conditions may arise dynamically (at any time) provided that the total number of faulty nodes at any given time is less than the node-connectivity n - 1 of the n-star. When a message is blocked due to faulty components, the source of the message is warned and requested to switch to a different node-disjoint path. The methods used to identify the paths, to propagate failure information back to source nodes, and to switch from a routing path to another incur little communication and computation overhead. We show that if the node failures occur 'reasonably' apart in time, then all messages will be routed on paths of length δ + ε where δ is the minimum distance between the source and the destination and ε is 0, 2, or 4. In the unlikely case where more failures occur in a 'short period', the algorithm still delivers all messages but via possibly longer paths.

APA, Harvard, Vancouver, ISO, and other styles

14

Parimalasundar, E., R. Senthil Kumar, V. S. Chandrika, and K. Suresh. "Fault diagnosis in a five-level multilevel inverter using an artificial neural network approach." Electrical Engineering & Electromechanics, no. 1 (January 4, 2023): 31–39. http://dx.doi.org/10.20998/2074-272x.2023.1.05.

Full text

Abstract:

Introduction. Cascaded H-bridge multilevel inverters (CHB-MLI) are becoming increasingly used in applications such as distribution systems, electrical traction systems, high voltage direct conversion systems, and many others. Despite the fact that multilevel inverters contain a large number of control switches, detecting a malfunction takes a significant amount of time. In the fault switch configurations diode included for freewheeling operation during open-fault condition. During short circuit fault conditions are carried out by the fuse, which can reveal the freewheeling current direction. The fault category can be identified independently and also failure of power switches harmed by the functioning and reliability of CHB-MLI. This paper investigates the effects and performance of open and short switching faults of multilevel inverters. Output voltage characteristics of 5 level MLI are frequently determined from distinctive switch faults with modulation index value of 0.85 is used during simulation analysis. In the simulation experiment for the modulation index value of 0.85, one second open and short circuit faults are created for the place of faulty switch. Fault is identified automatically by means of artificial neural network (ANN) technique using sinusoidal pulse width modulation based on distorted total harmonic distortion (THD) and managed by its own. The novelty of the proposed work consists of a fast Fourier transform (FFT) and ANN to identify faulty switch. Purpose. The proposed architecture is to identify faulty switch during open and short failures, which has to be reduced THD and make the system in reliable operation. Methods. The proposed topology is to be design and evaluate using MATLAB/Simulink platform. Results. Using the FFT and ANN approaches, the normal and faulty conditions of the MLI are explored, and the faulty switch is detected based on voltage changing patterns in the output. Practical value. The proposed topology has been very supportive for implementing non-conventional energy sources based multilevel inverter, which is connected to large demand in grid.

APA, Harvard, Vancouver, ISO, and other styles

15

Elijah Adebayo Olajuyin and Eniola Olubakinde. "Evaluation of reliability of power distribution components: A case study of Sagamu Substation, Ogun State." Global Journal of Engineering and Technology Advances 10, no. 1 (January 30, 2022): 065–74. http://dx.doi.org/10.30574/gjeta.2022.10.1.0180.

Full text

Abstract:

Power system especially the distribution system which is the closest to the consumer is very fundamental and important to a nation’s economy development and that was the reason this study titled “Evaluation of reliability of power system distribution components, a case study of Sagamu Substation, Ogun State” was carried out in response to the yawning of the consumer for reliable and stable power supply. It is indispensable to find means of shaping which component failure contributes most to the unavailability, outage or interruption of the distribution system, and how this unavailability essentially affects the customers. A year power outages data that caused as a result of failure on each of these components such as Switch gears, Supply lines (11Kv),Busbar, circuit breakers, Fuses, Switches, Outgoings feeders, Over current relays, Earth fault relays, Surge arresters, transformers e.t.c. were collected from Ibadan Electricity Distribution company (IBDEC), Sagamu Substation Zone, Ogun State and were typified in Table 1-11.The failure rate (f/yr) (λ) of transformer, switch gear, supply line (incoming),bus bars, circuit breakers, fuses, switches, outgoing feeder, over current relay, earth fault relay and surge arrester were evaluated as follows 0.0059, 0.0044, 0.0011, 0.6667, 0.0007, 0.0082, 0.0000, 0.0039, 0.0003, 0.0001 and 0.0000 respectively and others such as average outages time (hours) ,outages time hours and other basic reliability indices were calculated and illustrated in Table 12. Some of these failures were also represented in bar chart. This method relates reliability theory with the experience gained from statistics and practical knowledge of components failures and maintenance. The findings from this work revealed that fuses had the highest failure followed by transformers and the least was surge arresters and it was also discovered that the outages time was reduced during the December period. This approach can be applied to rural and urban distribution systems. This submission made reliability theory a powerful tool to assist distribution Engineers in solving difficult and complicated problems.

APA, Harvard, Vancouver, ISO, and other styles

16

Wang, Qun, Li Yao, and Zhan Long Zhang. "A New Optimal Method for Load Transfer in Power Distribution Network." Advanced Materials Research 989-994 (July 2014): 1177–80. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.1177.

Full text

Abstract:

According to the problem that when power failure occurs in distribution systems, load transfer is to recover the load downstream failures without any violation as fast as possible. This target is reached by switch operations and load cut. Using the stochastic optimization method to the solution of the problem, we can improve the efficiency of solution for the operation personnel to provide the reference scheme of load transfer. Test results of a 33 bus sample network have shown that the new method for load recovery can significantly reduce the losses caused by the failures and improve system reliability.

APA, Harvard, Vancouver, ISO, and other styles

17

Jamshidpour, Ehsan, Philippe Poure, Eskandar Gholipour, and Shahrokh Saadate. "Single-Switch DC–DC Converter With Fault-Tolerant Capability Under Open- and Short-Circuit Switch Failures." IEEE Transactions on Power Electronics 30, no. 5 (May 2015): 2703–12. http://dx.doi.org/10.1109/tpel.2014.2342878.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Perry, B. T., E. J. Rothwell, and L. L. Nagy. "Analysis of switch failures in a self-structuring antenna system." IEEE Antennas and Wireless Propagation Letters 4 (2005): 68–70. http://dx.doi.org/10.1109/lawp.2005.844129.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

ARSLAN, Burak, and Hasan TİRYAKİ. "Prediction of railway switch point failures by artificial intelligence methods." TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES 28, no. 2 (March 28, 2020): 1044–58. http://dx.doi.org/10.3906/elk-1906-66.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Sarafyazd, Morteza, and Mehrdad Jazayeri. "Hierarchical reasoning by neural circuits in the frontal cortex." Science 364, no. 6441 (May 16, 2019): eaav8911. http://dx.doi.org/10.1126/science.aav8911.

Full text

Abstract:

Humans process information hierarchically. In the presence of hierarchies, sources of failures are ambiguous. Humans resolve this ambiguity by assessing their confidence after one or more attempts. To understand the neural basis of this reasoning strategy, we recorded from dorsomedial frontal cortex (DMFC) and anterior cingulate cortex (ACC) of monkeys in a task in which negative outcomes were caused either by misjudging the stimulus or by a covert switch between two stimulus-response contingency rules. We found that both areas harbored a representation of evidence supporting a rule switch. Additional perturbation experiments revealed that ACC functioned downstream of DMFC and was directly and specifically involved in inferring covert rule switches. These results‏ reveal the computational principles of hierarchical reasoning, as implemented by cortical circuits.

APA, Harvard, Vancouver, ISO, and other styles

21

Alshmmari, Maha, Waleed Khalid Kadhim, and Maryam Adnan Al-Ethary. "Design Simulation and Test of Nano Electro Mechanical Switch Based on On-Line Test through Bias super position." Iraqi Journal of Nanotechnology, no. 1 (October 17, 2020): 1–6. http://dx.doi.org/10.47758/ijn.vi1.17.

Full text

Abstract:

In this paper, Nano Electromechanical Switch (NEMS) was designed and simulated by using MATLAB simulation, then was tested by on-line test through bias super-position. This switch has 4.5 nm thickness, offers low power dissipation and permits nonstop observing of all essential jobs. On the other hand, there are some challenges facing this Nano system. One of them is very difficult to resonators collective products with the same characteristics. The fabrication process was also a complex process and much hardness occurred during repetitive operations, which failure and stiction caused problems. In this work, a comparison between the response of a fault-free system and the system with some failures has been carried out. The test results showed a decrease in pull-in voltage with increasing overlap area as a result of wear failure mechanism in Nano Switch (NS). Creep in (NS) affected the value of the young modules and this increased the output voltage, also the crack in the beam of (NS) increased the effective mass and decreased output signal.

APA, Harvard, Vancouver, ISO, and other styles

22

Pei, Ying, Lin Niu, Shitao Wang, Haifeng Li, Qinghua Yin, Nannan Gao, Mengchao Ma, and Ye Ai. "Research on Maintenance Process Optimization of GW4-126DW Disconnecting Switch." Highlights in Science, Engineering and Technology 9 (September 30, 2022): 190–94. http://dx.doi.org/10.54097/hset.v9i.1771.

Full text

Abstract:

GW4-126DW disconnecting switch is a kind of switchgear commonly used in substations. When the disconnecting switch has defects or failures, it needs to be repaired. In this paper, the comparative analysis, system sorting, and summarization are used to optimize the maintenance process of the GW4-126DW disconnecting switch. After optimization, the overhaul process includes inspection before overhaul, dismantling of disconnecting switch, troubleshooting and elimination of defects, assembly and debugging, and inspection after overhaul. The research results have been applied to practice exercises for students majoring in electrical engineering. It has been proved that the maintenance process has clear logic, comprehensive operation steps and good practicality.

APA, Harvard, Vancouver, ISO, and other styles

23

Boumous, Z., and S. Boumous. "New Approach in the Fault Tolerant Control of Three-Phase Inverter Fed Induction Motor." Engineering, Technology & Applied Science Research 10, no. 6 (December 20, 2020): 6504–9. http://dx.doi.org/10.48084/etasr.3898.

Full text

Abstract:

This article provides an improved fault-tolerant control scheme for inverter-powered induction motors. The proposed strategy addresses the cancellation of power switch failures (IGBTs) regardless of their location in a reconfigurable induction motor control. The proposed fault-tolerant topology requires only minimal hardware modifications of the conventional six-switch three-phase drive, mitigating IGBT failures through reconfiguration based on the substitution of an entire inverter arm. The detection mechanism is based on the tridimensional method from which a database will be used for the learning of the neural network. In this method, the current from the stator is used as input to the system, so access to the induction motor is not necessary.

APA, Harvard, Vancouver, ISO, and other styles

24

Strizich, Michael. "Plastic-Encapsulated Microcircuits (PEMs) Failure Analysis." EDFA Technical Articles 7, no. 1 (February 1, 2005): 10–14. http://dx.doi.org/10.31399/asm.edfa.2005-1.p010.

Full text

Abstract:

Abstract Although plastic-encapsulated packaging dominates most of the IC industry, deprocessing and reliability testing continue to be a problem, particularly in industries making the switch from hermetically sealed ceramic packages. This article discusses the challenges designers and failure analysts face in the military and aerospace electronics industry stemming from the use of plastic packages. It provides examples of the types of failures encountered and describes the procedures used to detect and identify them.

APA, Harvard, Vancouver, ISO, and other styles

25

Jamshidpour, Ehsan, Philippe Poure, and Shahrokh Saadate. "Common Switch Fault Diagnosis for Two-Stage DC-DC Converters Used in Energy Harvesting Applications." Electronics 8, no. 3 (March 5, 2019): 293. http://dx.doi.org/10.3390/electronics8030293.

Full text

Abstract:

This paper proposes a new Unified Switch Fault Diagnosis (UFD) approach for two-stage non-isolated DC-DC converters used in energy harvesting applications. The proposed UFD is compared with a switch fault diagnosis consisting of two separate fault detection algorithms, working in parallel for each converter. The proposed UFD is simpler than the two parallel fault diagnosis methods in realization. Moreover, it can detect both types of switch failures, open circuit and short circuit switch faults. It can also be used for any two-stage non-isolated DC-DC converters based on two single switch converters, no matter the converter circuits in each stage. Some selected simulation and Hardware-in-the-Loop (HIL) experimentation results confirm the validity and efficiency of the proposed UFD. Also, the proposed UFD is applied successfully for fault-tolerant operation of a buck/buck–boost two-stage converter with synchronous control and a redundant switch.

APA, Harvard, Vancouver, ISO, and other styles

26

Liu, Shan, Bo Chen, Takis Zourntos, Deepa Kundur, and Karen Butler-Purry. "A Coordinated Multi-Switch Attack for Cascading Failures in Smart Grid." IEEE Transactions on Smart Grid 5, no. 3 (May 2014): 1183–95. http://dx.doi.org/10.1109/tsg.2014.2302476.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Moglia, Magnus, Kein Gan, Nathan Delbridge, Ashok K. Sharma, and Grace Tjandraatmadja. "Investigation of pump and pump switch failures in rainwater harvesting systems." Journal of Hydrology 538 (July 2016): 208–15. http://dx.doi.org/10.1016/j.jhydrol.2016.04.020.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Zhou, N., and R. H. Huan. "Asymptotic Stability of Delay-Controlled Nonlinear Stochastic Systems with Actuator Failures." Shock and Vibration 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/9081709.

Full text

Abstract:

The problem of asymptotic stability of delay-controlled nonlinear stochastic systems with actuator failures is investigated in this paper. Such a system is formulated as a continuous-discrete hybrid system based on the random switch model of failure-prone actuator. Time delay control force is converted into delay-free one by randomly periodic characteristic of the system. Using limit theorem and stochastic averaging, an approximate formula for the largest Lyapunov exponent of the original system is then derived, from which necessary and sufficient conditions for asymptotic stability are obtained. The validity and utility of the proposed procedure are demonstrated by using a stochastically driven nonlinear two-degree system with time delay feedback and actuator failure.

APA, Harvard, Vancouver, ISO, and other styles

29

Venter, Philip, and Martin van Eldik. "Booster Bearing Failure Reduction Through a Novel Thermodynamic Analysis." Journal of Failure Analysis and Prevention 22, no. 1 (December 2, 2021): 311–18. http://dx.doi.org/10.1007/s11668-021-01295-4.

Full text

Abstract:

AbstractThe gas booster station of a steel works has experienced excessive bearing failures since commissioning over two decades ago. This station was designed with redundancy, allowing for automatic switch-over between two gas booster fans. Bearing failures were observed, on average once every 15.7 days, with instances where both fans experienced simultaneous downtime. Booster failures resulted in regular station downtime, preventing Coke Oven Gas (COG) transport to an end user. This flammable by-product is used as a heat source and all unutilized volumes are flared, resulting in energy wastages. Furthermore, the absence of COG increases Natural Gas (NG) usage, procured at a cost. Traditional root cause analysis techniques failed to identify the cause of these excessive bearing failures. However, multiple in-depth data analysis studies resulted in a thermodynamic investigation, exposing liquid and solid particles within the COG to be responsible for the failures. This allowed for the design of an in-line particle collector, eliminating excessive failures. Following the particle collector installation, only two strategic bearing changes took place over the next 41 weeks, with reduced bearing vibration levels compared to before. The station experienced no failure downtime during this period, resulting in reduced COG flaring and thus improved energy utilization.

APA, Harvard, Vancouver, ISO, and other styles

30

Mohsenzade, Sadegh, Javad Naghibi, and Kamyar Mehran. "Reliability Enhancement of Power IGBTs under Short-Circuit Fault Condition Using Short-Circuit Current Limiting-Based Technique." Energies 14, no. 21 (November 5, 2021): 7397. http://dx.doi.org/10.3390/en14217397.

Full text

Abstract:

Like the widely-used semiconductor switch, Insulated Gate Bipolar Transistors (IGBTs) are subject to many failures and degradation in power electronic converters. In Short Circuit Fault (SCF), as the most reported failures in IGBTs, drastic, sudden temperature rise, and peak SCF current are widespread failures owing to a relatively long delay of the protection subsystem. This paper proposes a protection strategy to limit the junction temperature rise by limiting the SCF current by adding a small value resistor in the IGBT emitter. Second, it reduces the SCF current to a value much less than the saturated current. With the proposed control approach, sudden temperature rise during SCF is controlled, preventing significant failure in IGBTs. The extension of the permissible SCF time is achieved even for the cases with temporary arcs. A simple control loop activates in the SCF condition and does not create slow transients for the IGBT. The results of this paper are validated through simulation and experiment.

APA, Harvard, Vancouver, ISO, and other styles

31

Lv, Guixiang, and Liudong Xing. "Influence of Load on Reliability of Storage Area Networks." International Journal of Mathematical, Engineering and Management Sciences 6, no. 6 (December 1, 2021): 1533–52. http://dx.doi.org/10.33889/ijmems.2021.6.6.091.

Full text

Abstract:

During the coronavirus pandemic, telecommuting is widely required, making remote data access grow significantly. This requires highly reliable data storage solutions. Storage area networks (SANs) are one of such solutions. To guarantee that SANs can deliver the desired quality of service, cascading failures must be prevented, which occur when a single initial incident triggers a cascade of unexpected failures of other devices. One such incident is the data loading/overloading, causing the malfunction of one device and further cascading failures. Thus, it is crucial to address influence of data loading on the SAN reliability modeling and analysis. In this work, we make contributions by modeling the effects of data loading on the reliability of an individual switch device in SANs though the proportional-hazards model and accelerated failure-time model. Effects of loading on the reliability of the entire SAN are further investigated through dynamic fault trees and binary decision diagrams-based analysis of a mesh SAN system.

APA, Harvard, Vancouver, ISO, and other styles

32

Yepes, Alejandro G., Ignacio Gonzalez-Prieto, Oscar Lopez, Mario J. Duran, and Jesus Doval-Gandoy. "A Comprehensive Survey on Fault Tolerance in Multiphase AC Drives, Part 2: Phase and Switch Open-Circuit Faults." Machines 10, no. 3 (March 21, 2022): 221. http://dx.doi.org/10.3390/machines10030221.

Full text

Abstract:

Multiphase machines are very convenient for applications that require high reliability. In this two-part survey, the state of the art about fault tolerance in multiphase drives is reviewed. In Part 1, an overview including numerous fault types was presented, along with fundamental notions about multiphase drives. Here, in Part 2, the focus is placed on phase/switch open-circuit (OC) faults in particular, which have received the most attention in the literature. Phase OC failures involve OCs in stator phases or in converter-machine connections, and switch/diode OCs are frequently dealt with similarly or identically. Thanks to the phase redundancy of multiphase drives, their operation can be satisfactorily continued under a certain number of OCs. Nonetheless, the procedure to follow for this purpose is far from unique. For given OC fault conditions, numerous fault-tolerant possibilities can be found in the literature, each of them with different advantages and disadvantages. Moreover, a great variety of methods have also been devised to detect and diagnose phase/switch OC failures so that, as soon as possible, the most appropriate fault-tolerance measures are applied. Thus, given the broad literature about tolerance to phase/switch OC faults in multiphase drives, the survey presented here is expected to be of great interest for the research community and industry.

APA, Harvard, Vancouver, ISO, and other styles

33

Zhang, Zhan Long, Li Yao, and Qun Wang. "Reliability Evaluation for Distribution System Including Protection System Failures." Advanced Materials Research 989-994 (July 2014): 1181–84. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.1181.

Full text

Abstract:

A new model and method for incorporating the effect of protection system failures into distribution system reliability evaluation are developed this paper. Firstly, the distribution system is partitioned into zones with the auto (or non-auto) switch being the boundary; through the network equivalent approach, for each load point, three component groups are respectively formed by two types of zone-elements. Then two types of protection failures and their impacts on reliability modeling are discussed. Finally, the reliability Markov model of load point with protection failures has been developed. The test results of the samples demonstrate the practicability and validness of the method.

APA, Harvard, Vancouver, ISO, and other styles

34

Luo, Jun, and Boxun Liao. "A Fault-Tolerant Structure for Nano-Power Communication Based on the Multidimensional Crossbar Switch Network." International Transactions on Electrical Energy Systems 2022 (August 24, 2022): 1–8. http://dx.doi.org/10.1155/2022/4783847.

Full text

Abstract:

In order to realize fault tolerance and further reduce the transmission delay, a fault-tolerant structure design method for nano-power communication based on a multidimensional crossbar switch network is proposed. The TSV router is designed as a double crossbar structure, namely the master crossbar (MasterCrossbar) and the slave crossbar (SlaveCrossbar). Each input port of the TSV router is divided into two subports. The port connected to the master crossbar has no input buffer, and the port connected to the slave crossbar has an input buffer. Master crossbar is the first choice for data transmission, and slave crossbar is selected when it is busy to reduce the transmission delay of data packets and reduce power consumption. Dual crossbar switches can also realize the fault tolerance of crossbar switches. The experimental results show that the author's fault-tolerant scheme, without incorporating the double crossbar switch, still has a much smaller transmission delay than the reference because the author realizes fault tolerance for defective TSVs by adding bidirectional TSVs to replace faulty TSVs. Therefore, when there is a TSV failure, the reference transmission delay increases with the number of failures, but the author's design allows packets to be transmitted in the network without being affected; the author's bidirectional TSV fault-tolerant design is combined with the double crossbar design. After that, the transmission delay is smaller than the original, and the maximum transmission delay is about 40% faster than the reference. The authors' design is superior and improves the reliability of the 3DNoC system.

APA, Harvard, Vancouver, ISO, and other styles

35

Zhang, Che, Hong Xu, Libin Liu, Zhixiong Niu, and Peng Wang. "Kuijia: Traffic Rescaling in Software-Defined Data Center WANs." Security and Communication Networks 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/6361901.

Full text

Abstract:

Network faults like link or switch failures can cause heavy congestion and packet loss. Traffic engineering systems need a lot of time to detect and react to such faults, which results in significant recovery times. Recent work either preinstalls a lot of backup paths in the switches to ensure fast rerouting or proactively prereserves bandwidth to achieve fault resiliency. Our idea agilely reacts to failures in the data plane while eliminating the preinstallation of backup paths. We propose Kuijia, a robust traffic engineering system for data center WANs, which relies on a novel failover mechanism in the data plane called rate rescaling. The victim flows on failed tunnels are rescaled to the remaining tunnels and enter lower priority queues to avoid performance impairment of aboriginal flows. Real system experiments show that Kuijia is effective in handling network faults and significantly outperforms the conventional rescaling method.

APA, Harvard, Vancouver, ISO, and other styles

36

Manap, Mustafa, Srete Nikolovski, Aleksandr Skamyin, Rony Karim, Tole Sutikno, and Mohd Hatta Jopri. "An analysis of voltage source inverter switches fault classification using short time Fourier transform." International Journal of Power Electronics and Drive Systems (IJPEDS) 12, no. 4 (December 1, 2021): 2209. http://dx.doi.org/10.11591/ijpeds.v12.i4.pp2209-2220.

Full text

Abstract:

The dependability of power electronics systems, such as three-phase inverters, is critical in a variety of applications. Different types of failures that occur in an inverter circuit might affect system operation and raise the entire cost of the manufacturing process. As a result, detecting and identifying inverter problems for such devices is critical in industry. This study presents the short-time Fourier transform (STFT) for fault classification and identification in three-phase type, voltage source inverter (VSI) switches. TFR represents the signal analysis of STFT, which includes total harmonic distortion, instantaneous RMS current, RMS fundamental current, total non harmonic distortion, total waveform distortion and average current. The features of the faults are used with a rule-based classifier based on the signal parameters to categorise and detect the switch faults. The suggested method's performance is evaluated using 60 signals containing short and open circuit faults with varying characteristics for each switch in VSI. The classification results demonstrate the proposed technique is good to be implemented for VSI switches faults classification, with an accuracy classification rate of 98.3 percent.

APA, Harvard, Vancouver, ISO, and other styles

37

Manjunath, T. G., and Ashok Kusagur. "Fault Diagnosis and Reconfiguration of Multilevel Inverter Switch Failure-A Performance Perspective." International Journal of Electrical and Computer Engineering (IJECE) 6, no. 6 (December 1, 2016): 2610. http://dx.doi.org/10.11591/ijece.v6i6.12112.

Full text

Abstract:

Multilevel Inverters (MLI) gains importance in Distribution systems, Electrical Drive systems, HVDC systems and many more applications. As Multilevel Inverters comprises of number of power switches the fault diagnosis of MLI becomes tedious. This paper is an attempt to develop and analyze the fault diagnosis method that utilizes Artificial Neural Network to get it trained with the fault situations. A performance analysis of Genetic Algorithm (GA) and the Modified Genetic Algorithm (MGA), which optimizes the Artificial Neural Network (ANN) that trains itself on the fault detection, and reconfiguration of the Cascaded Multilevel Inverters (CMLI) is attempted. The Total Harmonic Distortion (THD) occurring due to switch failures or driver failures occurring in the CMLI is considered for this comparative analysis. Elapsed time of recovery, Mean Square Error (MSE) and the computational budgets of ANN are the performance parameters considered in this comparative analysis. Optimization is involved in the process of updating the weight and the bias values in the ANN network. Matlab based simulation is carried out and the results are obtained and tabulated for the performance evaluation. It was observed that Modified Genetic Algorithm performed better than the Genetic Algorithm while optimizing the ANN training.

APA, Harvard, Vancouver, ISO, and other styles

38

Manjunath, T. G., and Ashok Kusagur. "Fault Diagnosis and Reconfiguration of Multilevel Inverter Switch Failure-A Performance Perspective." International Journal of Electrical and Computer Engineering (IJECE) 6, no. 6 (December 1, 2016): 2610. http://dx.doi.org/10.11591/ijece.v6i6.pp2610-2620.

Full text

Abstract:

Multilevel Inverters (MLI) gains importance in Distribution systems, Electrical Drive systems, HVDC systems and many more applications. As Multilevel Inverters comprises of number of power switches the fault diagnosis of MLI becomes tedious. This paper is an attempt to develop and analyze the fault diagnosis method that utilizes Artificial Neural Network to get it trained with the fault situations. A performance analysis of Genetic Algorithm (GA) and the Modified Genetic Algorithm (MGA), which optimizes the Artificial Neural Network (ANN) that trains itself on the fault detection, and reconfiguration of the Cascaded Multilevel Inverters (CMLI) is attempted. The Total Harmonic Distortion (THD) occurring due to switch failures or driver failures occurring in the CMLI is considered for this comparative analysis. Elapsed time of recovery, Mean Square Error (MSE) and the computational budgets of ANN are the performance parameters considered in this comparative analysis. Optimization is involved in the process of updating the weight and the bias values in the ANN network. Matlab based simulation is carried out and the results are obtained and tabulated for the performance evaluation. It was observed that Modified Genetic Algorithm performed better than the Genetic Algorithm while optimizing the ANN training.

APA, Harvard, Vancouver, ISO, and other styles

39

Muthukumaran V., Vinothkumar V., Rose Bindu Joseph, Meram Munirathanam, and Balajee Jeyakumar. "Improving Network Security Based on Trust-Aware Routing Protocols Using Long Short-Term Memory-Queuing Segment-Routing Algorithms." International Journal of Information Technology Project Management 12, no. 4 (October 2021): 47–60. http://dx.doi.org/10.4018/ijitpm.2021100105.

Full text

Abstract:

Defending all single connection failures for a particular system, segment routing issue, the switch will focus on the problems of selecting a small subset of trust-aware routing to improve the deep learning (DL). In the end, even if there were multiple path failures, these paths may introduce long-term, unnecessary overload in the proposed long short-term memory networks-based queuing routing segmentation (LSTM-QRS) experience of reducing traffic delays and adjusting traffic length by reducing network bandwidth. The critical factor is a novel traffic repair technique used to create a traffic repair path that switches to software-defined network (SDN) using multiple routing and providing additional flexibility in re-routing using long short-term memory networks (LSTM)-based queuing routing segment (LSTM-QRS) algorithms. It reduces the repair path length and recommends replacing the target-based traffic with the connection-based traffic fault detection router to avoid targeted traffic network congestion.

APA, Harvard, Vancouver, ISO, and other styles

40

Jung, Jun-Hyung, Hyun-Keun Ku, Yung-Deug Son, and Jang-Mok Kim. "Open-Switch Fault Diagnosis Algorithm and Tolerant Control Method of the Three-Phase Three-Level NPC Active Rectifier." Energies 12, no. 13 (June 28, 2019): 2495. http://dx.doi.org/10.3390/en12132495.

Full text

Abstract:

This paper proposes a fault diagnosis and tolerant control methods for an open-switch fault caused in a three-phase three-level neutral-point-clamped (NPC) pulse-width modulation (PWM) active rectifier. The open-switch fault in the three-level NPC active rectifier causes a distortion in the input phase current and a ripple in the DC-link capacitor voltage. Therefore, proper fault diagnosis and tolerant control methods are required to prevent additional failures and performance degradation in the rectifier system. This paper conducted a detailed analysis of the effect of the single open-switch fault on the NPC PWM active rectifier and proposed a fault diagnosis method utilizing the DC link voltage and the phase angle of the input grid voltage. Furthermore, this paper proposes a fault-tolerant control method to reduce the effect of the open-switch fault by compensating a distorted reference voltage. The effectiveness of the proposed fault diagnosis and tolerant control methods are verified through experimental results.

APA, Harvard, Vancouver, ISO, and other styles

41

Sultana, Basra, and Mamun-ur-Rashid Khandker. "On Number of Planes of Rearrangeably Nonblocking Optical Banyan Networks with Link Failures." Journal of Scientific Research 1, no. 1 (December 20, 2008): 43–54. http://dx.doi.org/10.3329/jsr.v1i1.1070.

Full text

Abstract:

Vertically stacked optical banyan (VSOB) networks are attractive for serving as optical switching systems due to the desirable properties (such as the small depth and self-routing capability) of banyan network structures. Although banyan-type networks result in severe blocking and crosstalk, both these problems can be minimized by using sufficient number of banyan planes in the VSOB network structure. The number of banyan planes is minimum for rearrangeably nonblocking and maximum for strictly nonblocking structure. Both results are available for VSOB networks when there exist no internal link-failures. Since the issue of link-failure is unavoidable, we intend to find the minimum number of planes required to make a VSOB network nonblocking when some links are broken or failed in the structure. This paper presents the approximate number of planes required to make a VSOB networks rearrangeably nonblocking allowing link-failures. We also show an interesting behavior of theÂ blockingÂ probability of a faulty VSOB networks that the blocking probability may notÂ alwaysÂ increase monotonously withÂ theÂ increaseÂ ofÂ link-failures; blocking probabilityÂ decreasesÂ forÂ certain range ofÂ link-failures, and then increases again. We believe that such fluctuating behavior of blocking probability with the increase of link failure probability deserves special attention in switch design. Â Keywords: Banyan networks; Blocking probability; Switching networks; Vertical stacking; Link-failures.Â Â© 2009 JSR Publications. ISSN: 2070-0237(Print); 2070-0245 (Online). All rights reserved.Â DOI: 10.3329/jsr.v1i1.1070

APA, Harvard, Vancouver, ISO, and other styles

42

Shuvalov, Vyacheslav P., Boris P. Zelentsov, and Irina G. Kvitkova. "METHOD FOR CALCULATING THE AVAILABILITY FACTOR FOR A SYSTEM WITH REDUNDANCY. PASSIVE MODE." T-Comm 14, no. 8 (2020): 21–25. http://dx.doi.org/10.36724/2072-8735-2020-14-8-21-25.

Full text

Abstract:

The use of fiber-optic communication lines allows for the transfer of huge amounts of information per unit of time. Even short-term failures significantly affect the quality of services provided. The level of network reliability depends on how resilient the network infrastructure is to failures and how quickly recovery occurs after them. Reliability guarantees are the main component of quality of service agreements between operators and consumers. Most often, redundancy is used to ensure the required level of reliability indicators. The disadvantage of this approach is the high cost of network bandwidth, the advantage - is a short time to switch at the reserve after a failure is detected. In order to reduce costs, in some cases, the 1:N backup option is used (one backup path is allocated for N working paths). In this paper, we consider the case of 1:2, when one backup path is allocated for two working paths. In this case active and passive switching modes are possible. When switching is active, if both working paths fail, the traffic of one of them switches to the backup path. After restoring the working path, traffic switches to the restored path, i.e. the backup path is freed. It is replaced by traffic from another failed path. A special feature of passive mode consists in that after the backup path is released, it does not deal with the traffic of the second failed path. There are several ways to restore traffic over a failed work path:. the second working path starts to recover after the first one is restored; the second working path starts to recover simultaneously with the first one. In either case, the traffic of the first path is switched back from the backup to the working path after it is restored. This paper presents a method for calculating the conditional probability that the backup path will be used for transmitting traffic from one of the working paths if both paths fail. The formula for calculating the unavailability factor of working paths is given.

APA, Harvard, Vancouver, ISO, and other styles

43

Mimouni, A., S. Laribi, M. Sebaa, T. Allaoui, and A. A. Bengharbi. "Fault diagnosis of power converters in a grid connected photovoltaic system using artificial neural networks." Electrical Engineering & Electromechanics, no. 1 (January 4, 2023): 25–30. http://dx.doi.org/10.20998/2074-272x.2023.1.04.

Full text

Abstract:

Introduction. The widespread use of photovoltaic systems in various applications has spotlighted the pressing requirement for reliability, efficiency and continuity of service. The main impediment to a more effective implementation has been the reliability of the power converters. Indeed, the presence of faults in power converters that can cause malfunctions in the photovoltaic system, which can reduce its performance. Novelty. This paper presents a technique for diagnosing open circuit failures in the switches (IGBTs) of power converters (DC-DC converters and three-phase inverters) in a grid-connected photovoltaic system. Purpose. To ensure supply continuity, a fault-diagnosis process is required throughout all phases of energy production, transfer, and conversion. Methods. The diagnostic approach is based on artificial neural networks and the extraction of features corresponding to the open circuit fault of the IGBT switch. This approach is based on the Clarke transformation of the three-phase currents of the inverter output as well as the calculation of the average value of these currents to determine the exact angle of the open circuit fault. Results. This method is able to effectively identify and localize single or multiple open circuit faults of the DC-DC converter IGBT switch or the three-phase inverter IGBT switches.

APA, Harvard, Vancouver, ISO, and other styles

44

Abuelnaga, Ahmed, Mehdi Narimani, and Amir Sajjad Bahman. "Power electronic converter reliability and prognosis review focusing on power switch module failures." Journal of Power Electronics 21, no. 6 (March 19, 2021): 865–80. http://dx.doi.org/10.1007/s43236-021-00228-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Jo, Ha-Rang, Youngjong Ko, and Kyo-Beum Lee. "Influence of open-switch failures on DC-link capacitors in hybrid ANPC inverters." Journal of Power Electronics 21, no. 11 (September 28, 2021): 1735–42. http://dx.doi.org/10.1007/s43236-021-00309-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Bahrebar, Poona, and Dirk Stroobandt. "Abacus turn model-based routing for NoC interconnects with switch or link failures." Microprocessors and Microsystems 59 (June 2018): 69–91. http://dx.doi.org/10.1016/j.micpro.2018.01.005.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Shenai, Krishna, Philip G. Neudeck, M. Dudley, and Robert F. Davis. "Material Defects and Rugged Electrical Power Switching in Semiconductors." Materials Science Forum 717-720 (May 2012): 1077–80. http://dx.doi.org/10.4028/www.scientific.net/msf.717-720.1077.

Full text

Abstract:

A paradigm shift in the development and utilization of power semiconductor switch technology is proposed. This new "top down" approach begins with the field-reliability of a power semiconductor switch in a power converter circuit is subjected to long-term repetitive-switching under stressful field-operating conditions. This approach is derived from extensive field-reliability data collected on state-of-the-art silicon power MOSFETs in compact computer/telecom power supplies that clearly suggests that power MOSFET field-failures were primarily caused by bulk material defects. A careful survey of power switch technologies reported to-date in Silicon Carbide (SiC) and Gallium Nitride (GaN) further suggests that excessive bulk material defects have predominantly hindered the development and commercialization of cost-effective, high-performance, and reliable high-power devices. A reliability-driven approach is likely to "unlock" the vast potential of SiC (and GaN for moderate power levels) power device technology for high-voltage and high-power switching electronics in order to impact transformative changes.

APA, Harvard, Vancouver, ISO, and other styles

48

Memon, Sheeba, Jiawei Huang, Hussain Saajid, Naadiya Khuda Bux, Arshad Saleem, and Yazan Aljeroudi. "Novel Multi-Level Dynamic Traffic Load-Balancing Protocol for Data Center." Symmetry 11, no. 2 (January 28, 2019): 145. http://dx.doi.org/10.3390/sym11020145.

Full text

Abstract:

Typically, the production data centers function with various risk factors, such as for instance the network dynamicity, topological asymmetry, and switch failures. Hence, the load-balancing schemes should consider the sensing accurate path circumstances as well as the reduction of failures. However, under dynamic traffic, current load-balancing schemes use the fixed parameter setting, resulting in suboptimal performances. Therefore, we propose a multi-level dynamic traffic load-balancing (MDTLB) protocol, which uses an adaptive approach of parameter setting. The simulation results show that the MDTLB outperforms the state-of-the-art schemes in terms of both the flow completion time and throughput in typical data center applications.

APA, Harvard, Vancouver, ISO, and other styles

49

Apostolidis, Apostolos, Efstathios Papaefstathiou, and Sotirios Gatsos. "Intravesical Botox for Overactive Bladder: How to Minimize Complications and Manage Failures." Current Drug Targets 21, no. 15 (November 27, 2020): 1527–36. http://dx.doi.org/10.2174/1389450121666200621194732.

Full text

Abstract:

Intravesical Botox has become a widespread treatment for patients with refractory overactive bladder. Further to its acknowledged efficacy, both physicians and patients must be fully aware of possible complications, such as urinary tract infections, incomplete bladder emptying or even urinary retention and the possible need for intermittent self-catheterizations, fatigue, muscle weakness, transient hematuria and autonomic dysreflexia. Careful patient selection, particularly in terms of comorbidities, caution with technical aspects of the procedure such as the use of fine specifically designed injection needles, treatment of baseline UTIs or bacteriuria and avoidance of bladder overfilling could be the main measures, in addition to rigorous patient follow-up, to minimize the risk of post-Botox UTIs, hematuria, autonomic dysreflexia, and retention. Management of Botox failures is currently an unchartered area, starting with the definition of failure per se. Nevertheless, dose increase, particularly in neurogenic patients, increase of treatment frequency, switch to abobotulinumtoxinA, prolongation of injection intervals with add-on oral therapy, use of percutaneous tibial nerve stimulation or sacral neuromodulation and alleviation of risk factors for failure such as UTIs may be part of the management algorithm for Botox failures. As there is little evidence base to support such proposals and as the use of intravesical Botox is increasingly becoming a part of common urological practice, further research into the field of Botox failures and complications is needed so that both physicians and patients are granted with more solid, viable options.

APA, Harvard, Vancouver, ISO, and other styles

50

Schechter, Chen. "Commentary – Let’s switch cognitive gears: leading school improvement through learning from failures and successes." Journal of Educational Administration 59, no. 4 (July 18, 2021): 532–41. http://dx.doi.org/10.1108/jea-08-2021-265.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Switch failures'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles