S-memV: Split Migration of Large-Memory Virtual Machines in IaaS Clouds

Recently, Infrastructure-as-a-Service clouds provide virtual machines (VMs) with a large amount of memory. Such large-memory VMs make VM migration difficult because it is costly to reserve large-memory hosts as the destination. Using virtual memory is a remedy for this problem, but virtual memory is incompatible with the memory access pattern in VM migration. Consequently, large performance degradation occurs during and after VM migration due to excessive paging. This paper proposes split migration of large-memory VMs with S-memV. Split migration migrates a VM to one main host and one or more sub-hosts. It divides the memory of a VM and transfers memory likely to be accessed to the main host. Since it transfers the rest of the memory directly to the sub-hosts, no paging occurs during VM migration. After split migration, remote paging is performed between the main host and the sub-hosts, but its frequency is lower thanks to memory splitting that is aware of remote paging. We have implemented S-memV in KVM and showed that the performance of split migration and application performance after VM migration were comparable to that of traditional VM migration with sufficient memory.IEEE International Conference on Cloud Computing (IEEE Cloud 2018), July 2-7, 2018, San Francisco, CA, US

Particulate plutonium released from the Fukushima Daiichi meltdowns

Traces of Pu have been detected in material released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March of 2011; however, to date the physical and chemical form of the Pu have remained unknown. Here we report the discovery of particulate Pu associated with cesium-rich microparticles (CsMPs) that formed in and were released from the reactors during the FDNPP meltdowns. The Cs-pollucite-based CsMP contained discrete U(IV)O2 nanoparticles,Peer reviewe

Abundance and distribution of radioactive cesium-rich microparticles released from the Fukushima Daiichi Nuclear Power Plant into the environment

International audienceThe abundance and distribution of highly radioactive cesium-rich microparticles (CsMPs) that were released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) during the first stage of the nuclear disaster in March 2011 are described for 20 surface soils collected around the FDNPP. Based on the spatial distribution of the numbers (particles/g) and radioactive fraction (RF) of the CsMPs in surface soil, which is defined as the sum of the CsMP radioactivity (in Bq) divided by the total radioactivity (in Bq) of the soil sample, three regions of particular interest have been identified: i.) near-northwest (N-NW), ii.) far-northwest (F-NW), and iii.) southwest (SW). In these areas, the number and RF of CsMPs were determined to be 22.1–101 particles/g and 15.4–34.0%, 24.3–64.8 particles/g and 36.7–37.4%, and 0.869–8.00 particles/g and 27.6–80.2%, respectively. These distributions are consistent with the plume trajectories of material released from the FDNPP on March 14, 2011, in the late afternoon through to the late afternoon of March 15, 2011, indicating that the CsMPs formed only during this short period. Unit 3 is the most plausible source of the CsMPs at the beginning of the release based on an analysis of the sequence of release events. The lower RF values in the N-NW region indicate a larger influence from subsequent plumes that mainly consisted of soluble Cs species formed simultaneously with precipitation. The quantitative map of the distribution of CsMPs provides an important understanding of CsMP dispersion dynamics and can be used to assess risks in inhabited regions

Recent Progress at KEKB

We summarize the machine operation of KEKB during past one year. Progress for this period, causes of present performance limitations and future prospects are described

Achievements of KEKB

The machine commissioning of KEKB started in December 1998 and its operation was terminated at the end of June 2010 to upgrade KEKB to SuperKEKB. In this paper, we summarize the history of KEKB and show the achievements made there