Mikiko Sato

The Relationship between Media Consumption and Health-Related Anxieties after the Fukushima Daiichi Nuclear Disaster

Background The Fukushima Daiichi nuclear disaster caused a global panic by a release of harmful radionuclides. In a disaster setting, misusage of contemporary media sources available today can lead to disseminated incorrect information and panic. The study aims to build a scale which examines associations between media and individual anxieties, and to propose effective media usages for future disaster management. Methods The University of Tokyo collaborated with the Fukushima local government to conduct a radiation-health-seminar for a total of 1560 residents, at 12 different locations in Fukushima. A 13 item questionnaire collected once before and after a radiation-seminar was used on factor analysis to develop sub-scales for multiple regression models, to determine relationships between the sub-scales and media type consumed. A paired t–test was used to examine any changes in sub-scale of pre- and post-seminar scores. Results Three sub-scales were revealed and were associated with different media types: was with rumors, while concern for the future was positively associated with regional-newspapers and negatively with national-newspapers. Anxiety about social-disruption was associated with radio. The seminar had a significant effect on anxiety reduction for all the three sub-scales. Conclusion Different media types were associated with various heightened concerns, and that a radiation seminar was helpful to reduce anxieties in the post-disaster setting. By tailoring post-disaster messages via specific media types, i.e., radio, it may be possible to effectively convey important information, as well as to calm fears about particular elements of post-disaster recovery and to combat rumors.

GPU acceleration for Sudoku solution with genetic operations

In this paper, we use the problem of solving Sudoku puzzles to demonstrate the possibility of achieving practical processing time through the use of GPUs for parallel processing in the application of genetic computation to problems for which the use of genetic computing has not been investigated before because of the processing time problem. To increase accuracy, we propose a genetic operation that takes building-block linkage into account. As a parallel processing model for higher performance, we use a multiple-population coarse-grained GA model to counter initial value dependence under the condition of a limited number of individuals. Specifically, we show that it is possible to reach a solution in a few seconds of processing time with a correct solution rate of 100%, even for extremely difficult problems by parallel processing of genetic computation on a GeForce GTX 460, a commercial GPU produced by the NVIDIA Corporation.

Multithreaded Two-Phase I/O: Improving Collective MPI-IO Performance on a Lustre File System

ROMIO, a representative MPI-IO implementation, has been widely used in recent large-scale parallel computations. The two-phase I/O optimization scheme of ROMIO improves I/O performance for non-contiguous access patterns, however, this scheme still has room to improve performance to make it suitable for recent data-intensive computing. We propose overlapping data exchange operations with file I/O operations by using a multithreaded scheme to achieve further I/O throughput improvement. We show up to 60% improvement by the multithreaded two-phase I/O relative to the original two-phase I/O in performance evaluation of collective write operations on a Lustre file system of a Linux PC cluster.

First results of performance comparisons on many-core processors in solving QAP with ACO: kepler GPU versus xeon PHI

This paper compares the performance of parallel computation on two types of many-core processors, Tesla K20c GPU and Xeon Phi 5110P, in solving the quadratic assignment problem (QAP) with ant colony optimization (ACO). The results show that the performance on Xeon Phi 5110P is not so promising compared to the Tesla K20c GPU on these problems. Further efficient implementation methods must be investigated for Xeon Phi.

Acceleration of genetic algorithms for sudoku solution on many-core processors

In this paper, we use the problem of solving Sudoku puzzles to demonstrate the possibility of achieving practical processing time through the use of many-core processors for parallel processing in the application of genetic computation. To increase accuracy, we propose a genetic operation that takes building-block linkage into account. As a parallel processing model for higher performance, we use a multiple-population coarse-grained GA model to counter initial value dependence under the condition of a limited number of individuals. The genetic manipulation is also accelerated by the parallel processing of threads. In an evaluation using even very difficult problems, we show that execution times of several tens of seconds and several seconds can be obtained by parallel processing with the Intel Corei7 and NVIDIA GTX460, respectively, and that a correct solution rate of 100% can be achieved in either case.

Proposal of a multi-core processor from the viewpoint of evolutionary computation

The use of low-cost multi-core processors that target small-scale parallelism of several or several tens of processing units has recently spread to general-purpose personal computers. As part of this trend, research on converting evolutionary computation to parallel processing on multi-core processors has begun. In our research, we place importance on proposing multi-core processor architectures from the viewpoint of evolutionary computation and on proposing indices for identifying chips that exhibit high affinity with evolutionary computation from among existing multi-core processors. This paper takes a first step in this direction by focusing on local memory built into a multi-core processor and proposing a specification that allows the contents of local memory in any core to be directly accessed by any other core without using main memory. We describe a desktop comparison with single-core processors and general multi-core processors and show that a speed-up effect should be expected with the proposed specification for both fine-grain and coarse-grained parallelization techniques. We also describe an evaluation on actual multi-core processor for the case of fine-grain parallelization and show that the speed-up effect is also useful in reducing energy consumption.

Delegation-Based MPI communications for a hybrid parallel computer with many-core architecture

Many-core architecture draws much attention in HPC community towards the Exascale era. Many ongoing research activities using GPU or the Many Integrated Core (MIC) architecture from Intel exist worldwide. Many-core CPUs have a great deal of impact to improve computing performance, however, they are not favorable for heavy communications and I/Os which are essential for MPI operations in general. We have been focusing on the MIC architecture as many-core CPUs to realize a hybrid parallel computer in conjunction with multi-core CPUs. We propose a delegation mechanism for scalable MPI communications issued on many-core CPUs so as to play delegated operations on multi-core ones. This architecture also minimizes memory utilization of not only many-core CPUs but also multi-core ones by deploying multi-layered MPI communicator information. Here we evaluated the delegation mechanism on an emulated hybrid computing environment. We show our innovative design and its performance evaluation on the emulated environment in this paper.

pmqFlow: Design of propagation time measuring QoS system with OpenFlow for process automation

This paper introduces a novel QoS architecture for process automation. The proposed architecture leverages the concept of Software Defined Network. The architecture maintains the real-time communications based on the measured propagation time. It maintains the configurations by detecting and predicting the change of propagation time in addition to queue usage. The authors utilize the OpenFlow with simple extension to measure the propagation time. The extension allows measuring propagation time with intelligent intermediate network equipment rather than changing process automation end-device. It is important requirement to keep the end-device untouched since the devices have small resources and applications are widely prevailed.

Parallelization and fault-tolerance of evolutionary computation on many-core processors

We report on fault-tolerant technology for use with high-speed parallel evolutionary computation on many-core processors. In particular, for distributed GA models which communicate between islands, we propose a method where an islands ID number is added to the header of data transferred by this island for use in fault detection, and we evaluate this method using Deceptive functions and Sudoku puzzles. As a result, we show that it is possible to detect single stuck-at faults with practically negligible overheads in applications where the time spent performing genetic operations is large compared with the data transfer speed between islands. We also show that it is still possible to obtain an optimal solution when a single stuck-at fault is assumed to have occurred, and that increasing the number of parallel threads has the effect of making the system less susceptible to faults and more sustainable.

A design of hybrid operating system for a parallel computer with multi-core and many-core processors

This paper describes the design of an operating system to manage the hybrid computer system architecture with multi-core and many-core processors for Exa-scale computing. In this study, a host operating system (Host OS) on a multi-core processor performs some functions of a lightweight operating system (LWOS) on a many-core processor, in order to dedicate to executing the application program on a many-core processor. In particular, to ensure that LWOS execution does not disturb the application program executed on the many-core processor, the functions such as process management, memory management, and I/O management are delegated to the Host OS. To demonstrate this design, we made an prototype system of a computer equipped with a multi-core processor and a many-core processor using an Intel Xeon dual-core processor system. The Linux and original LWOS were loaded on to each processor and the overhead for executing the program for LWOS from Linux was evaluated. Using this prototype system, the LWOS process can be started with at least 110 μsec overhead for the many-core program.