System-Level Reliability and Sensitivity Analyses for Three Fault-Tolerant System Architectures

Author(s):  
Joanne Bechta Dugan ◽  
Michael R. Lyu
2017 ◽  
Vol 26 (07) ◽  
pp. 1750111 ◽  
Author(s):  
Jie Wang ◽  
Jiwei Liu

The evolvable hardware (EHW) is widely used in the design of fault-tolerant system. Fault-tolerant system is really a real-time system, and the recovery time is necessary in fault detection and recovery. However, when applying EHW, real-time characteristic is usually ignored. In this paper, a fault-tolerant strategy based on EHW is proposed. The recovery time, predicted by the fault tree analysis (FTA), is considered as a constraint condition. A configuration library is set up in the design phase to accelerate the repair process of the anticipated faults. An evolvable algorithm (EA) based on similarity is applied to evolve the repair circuit for the unanticipated faults. When the library reaches the upper, the target system is reconfigured by the EA-repair technology. Extensive experiments are conducted to show that our method can improve the fault-tolerance of the system while satisfying the real-time requirement on FPGA platform. In a long run system, our method can keep a higher fault recovery rate.


2021 ◽  
pp. OP.20.01082
Author(s):  
Stephanie B. Wheeler ◽  
Lisa P. Spees ◽  
Bradford E. Jackson ◽  
Christopher D. Baggett ◽  
Lauren E. Wilson ◽  
...  

PURPOSE: Availability of targeted oral anticancer agents (OAAs) has transformed care for patients with metastatic renal cell carcinoma (mRCC). Our objective was to identify patterns and predictors of OAA use within 12 months after mRCC was detected to understand real-world adoption of OAAs. METHODS: We used a novel, North Carolina cancer registry–linked multipayer claims data resource to examine patterns of use of five oral therapies among patients with mRCC diagnosed in 2006-2015, with claims through 2016. Patients were required to have 12 months of continuous enrollment before metastatic index date. Log-Poisson models estimated unadjusted and adjusted risk ratios (RRs) for associations between patient characteristics and OAA use. In sensitivity analyses, we used a competing risk framework to estimate adjusted risk differences in OAA use. RESULTS: Our population-based study of 713 patients demonstrated low (37%) OAA use during the first year after metastatic index date among both publicly and privately insured patients, with shifting patterns of use consistent with regulatory approvals over time. Compared with patients age 18-49 years, patients age 70-74 years were half likely to use OAAs (95% confidence limit [CL], 0.34 to 0.78) and patients age 80+ years were 71% less likely to use OAAs (95% CL, 0.17 to 0.50). Patients with two comorbidities (RR, 0.73; 95% CL, 0.55 to 0.98) and those with 3+ comorbidities (RR, 0.68; 95% CL, 0.50 to 0.91) were less likely to receive OAA than those without comorbidities. Patients with higher frailty also had lower OAA utilization (RR, 0.67; 95% CL, 0.52 to 0.85). CONCLUSION: These findings suggest a need to better understand the system-level and provider-level drivers of OAA underuse, as well as OAA adherence and associated survival.


2020 ◽  
Vol 65 (2) ◽  
pp. 66
Author(s):  
M. Petrescu ◽  
R. Petrescu

The implementation of a fault-tolerant system requires some type of consensus algorithm for correct operation. From Paxos to View-stamped Replication and Raft multiple algorithms have been developed to handle this problem. This paper presents and compares the Raft algorithm and Apache Kafka, a distributed messaging system which, although at a higher level, implements many concepts present in Raft (strong leadership, append-only log, log compaction, etc.).This shows that mechanisms conceived to handle one class of problems (consensus algorithms) are very useful to handle a larger category in the context of distributed systems.


Sign in / Sign up

Export Citation Format

Share Document