Many existing real time commit protocols try to improve system performance by allowing a committing cohort to lend its data to an executing cohort, thus reducing data inaccessibility. They block the borrower from sending WORKDONE/PREPARED message and restrict them from lending data so that transaction abort chain is limited to one. Thus, transaction execution time increases. This paper proposes a modified real time commit protocol for distributed real time database systems (DRTDBS), Allow Commit Dependent and in Time borrowers for Incredible Value added data lending without extended abort chain (ACTIVE), where borrower cohorts are categorized as commit and abort dependent. Further, the commit dependent borrowers can lend data to executing cohorts with still limiting the transaction abort chain to one only and reducing the data inaccessibility. Also, an incoming executing cohort having borrowing factor greater than one can only borrow the dirty data items from lender. This minimizes the fruitless borrowing by the cohort. The performance of ACTIVE is compared with PROMPT, 2SC and SWIFT protocols for both main memory resident and disk resident databases with and without communication delay. Simulation results show that the proposed protocol improves the system performance up to 4% as transaction miss percentage
Electrical signature–based technique, due to its non-intrusive nature, is very useful for condition monitoring of rotary machines. Major challenge is the dominance of line frequency in the current signature. The present study focused on decreasing this dominance of the line frequency by obtaining the residual signals through autoregressive modeling. The residual signals are used further to extract the health-related features. The recently developed weighted multi-scale fluctuation-based dispersion entropy features are extracted as health indicators. The extracted health indicators are used for classification of different types of planetary gearbox faults. The results reflect that the proposed methodology has the potential for diagnosing different types of planetary gearbox faults with acceptable accuracy values.
Highly formable interstitial‐free steel has been subjected to corrode in wet‐dry salt spray (WDSS) and immersion corrosion (IMCC) conditions in 5, 10, 20, 30, and 45 days to investigate its corrosion behavior in simulated‐marine environment at the same temperature using 5 wt.% NaCl. The corrosion mechanisms and their effects have been studied and compared on the basis of weight loss and mechanical properties. Results revealed that corrosion rate in WDSS is about 9.5 times higher than IMCC. The corrosion coefficient (n) values for WDSS and IMCC have been observed as 0.99 and 0.35, respectively, which are evident for the protective nature of rust. The corrosion mechanisms and rust constituents may attribute different corrosion kinetics in both conditions. Moreover, the rate of degradation in yield strength and fracture strain in WDSS is 2 and 2.5 times higher than IMCC respectively; however, in the case of ultimate tensile strength the degradation rate is nearly same. It has also been observed that the higher pitting corrosion in WDSS may lead to change the failure mode from ductile to mix‐mode after 30 and 45 days of corrosion as authenticated from scanning electron microscopic images.
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