Healthcare applications store private user data on cloud servers and perform computation operations that support several patient diagnoses. Growing cyber-attacks on hospital systems result in user data being held at ransom. Furthermore, mathematical operations on data stored in the Cloud are exposed to untrusted external entities that sell private data for financial gain. In this paper, we propose a privacy-preserving scheme using homomorphic encryption to secure medical plaintext data from being accessed by attackers. Secret sharing distributes computations to several virtual nodes on the edge and masks all arithmetic operations, preventing untrusted cloud servers from learning the tasks performed on the encrypted patient data. Virtual edge nodes benefit from cloud computing resources to accomplish computing-intensive mathematical functions and reduce latency in device–edge node data transmission. A comparative analysis with existing studies demonstrates that homomorphically encrypted data stored at the edge preserves data privacy and integrity. Furthermore, secret sharing-based multi-node computation using virtual nodes ensures data confidentiality from untrusted cloud networks.

Environmentally-assisted fatigue evaluations are to be conducted for ASME Code Class 1 piping components in a pressurized water reactor. Environmental fatigue correction factor method for incorporating the effects of light water reactor coolant environments into ASME Section III fatigue evaluations was investigated in this paper. Both ASME Code NB-3200 and NB-3600 methods were used to determine the usage factors of the piping components. Considered in these calculations were the loads which are generally applied to the piping design for the nuclear power plants such as seismic, thermal expansions, thermal transients, thermal stratifications and building-filtered dynamic loadings. For the practical applications of NB-3600 method, regarded as the simple and conservative approach, to the piping components, it was presumed that the stress intensity and/or strain time histories for all or some of the external loadings were not known; therefore the time consistency might not be considered in calculating the usage factors as well as environmental correction factors (F en ). In NB-3200 method in contrast to NB-3600, the stress variations with time for all loads except for the dynamic loads were obtained for the fatigue evaluations in LWR environments, and therefore the time consistency was considered. The results showed that the environmental correction factors as well as in-air cumulative usage factors calculated from NB-3200 methods were significantly less than those from NB-3600 rules. In addition, comparing the results of conventional ASME fatigue evaluation applied until 2006 to the ones in accordance with USNRC RG 1.207 issued on 2007, one may identify that the cumulative usage factors in LWR environments were larger than the conventional one due to the change of design fatigue curves as well as F en factors accounting for the environmental effects on fatigue. Although this work was focused on the detailed calculations of the usage factors and F en values, one might identify or suggest a number of areas requiring further clarification or research through the efforts of this study, which were not yet addressed. A few items needed to be clarified, especially for NB-3600-based fatigue evaluations, are also discussed in this paper.

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