Efficient and Flexible Checkpoint/Restore of Split-memory Virtual Machines

Recently, clouds provide virtual machines (VMs) with a large amount of memory for big data analysis. For easier migration of such VMs, split migration divides the memory of a VM into several pieces and transfers them to multiple hosts. Since the migrated VM called a split-memory VM needs to exchange memory data between the hosts, it is inherently subject to host and network failures. As a countermeasure, a checkpoint/restore mechanism has been used to periodically save the state of a VM, but the traditional mechanism is not suitable for split-memory VMs. It has to move a large amount of memory data between hosts during checkpointing and can just restores a normal VM on one host. This paper proposes D-CRES for efficient and flexible checkpoint/restore of split-memory VMs. D-CRES achieves fast checkpointing by saving the memory of a VM in parallel at all the hosts without moving memory data. For live checkpointing, it consistently saves the memory of a running VM by considering memory data exchanged by the VM itself. In addition, it enables a split-memory VM to be restored in parallel at multiple hosts. We have implemented checkpoint/restore of D-CRES in KVM and showed that the performance was up to 5.4 times higher than that of using the traditional mechanism.2020 International Conference on Computational Intelligence (ICCI), 8-9 October, 2020, Universiti Teknologi PETRONAS (UTP), Bandar Seri Iskandar, Malaysia（オンライン開催に変更

Transmission scheduling for tandemly-connected sensor networks with heterogeneous packet generation rates

A tandemly-connected multi-hop wireless sensor network model is studied. Each node periodically generates packets in every cycle and relays the packets in a store-and-forward manner on a lossy wireless link between two adjacent nodes. To cope with a considerable number of packet losses, we previously proposed a packet transmission scheduling framework, in which each node transmits its possessing packets multiple times according to a static time-slot allocation to recover or avoid packet losses caused either by physical conditions on links or by interference of simultaneous transmissions among near-by nodes. However, we assumed that the packet generation rate is identical over all nodes, which is not always realistic. Therefore, in this paper, we enhance our work to the case of heterogeneous packet generation rates. We derive a static time-slot allocation maximizing the probability of delivering all packets within one cycle period. By using an advanced wireless network simulator, we show its effectiveness and issues to be solved.12th International Workshop on Information Network Design (WIND-2020), in conjunction with 12th International Conference on Intelligent Networking and Collaborative Systems (INCoS-2020), August 31st - September 2nd, 2020, University of Victoria, Canada（新型コロナ感染拡大に伴い、現地開催中止

Printed 5-V organic operational amplifiers for various signal processing

The important concept of printable functional materials is about to cause a paradigm shift that we will be able to fabricate electronic devices by printing methods in air at room temperature. One of the promising applications of the printed electronics is a disposable electronic patch sensing system which can monitor the health conditions without any restraint. Operational amplifiers (OPAs) are an essential component for such sensing system, since an OPA enables a wide variety of signal processing. Here we demonstrate printed OPAs based on complementary organic semiconductor technology. They can be operated with a standard safe power source of 5 V with a minimal power consumption of 150 nW, and used as amplifiers, a variety of mathematical operators, signal converters, and oscillators. The printed micropower organic OPAs with the low voltage operation and the high versatility will open up the disposable electronic patch sensing system in near future

A scaling relation of anomalous Hall effect in ferromagnetic semiconductors and metals

A scaling relation of the anomalous Hall effect recently found in a ferromagnetic semiconductor (Ti,Co)O_2_ is compared with those of various ferromagnetic semiconductors and metals. Many of these compounds with relatively low conductivity sigma_xx_ < 10^4 ohm^-1 cm^-1 are also found to exhibit similar relation: anomalous Hall conductivity sigma_AH_ approximately scales as sigma_AH_ proportional to sigma_xx_^1.6, that is coincident with a recent theory. This relation is valid over five decades of sigma_xx_ irrespective of metallic or hopping conduction.Comment: 10 pages, 1 table, 1 figure. To be published in Jpn. J. Appl. Phys. 46, issue 26 (2007

Thermal Stability of a Fully Printed Ultra-Thin Organic Pre-Amplifier Circuit Meant for on-Skin applications

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