As a high efficiency and energy saving engine, gas turbine engines are widely used in modern aircraft and power plant.
After burning all the fuel mixture inside the combustion chamber, gas with high temperature and pressure will be exhausted from the combustion chamber to the turbine stage, the method which gas turbine engine use to generate power is using the hot gas to drive the turbine blades in the turbine stage inside the engine, as a consequence turbine blades have to withstand high temperature and stress which is harmful to the turbine structure.
In order to protect the turbine blades inside the engine, effective cooling techniques are applied on the turbine blades, among all those cooling techniques film cooling is considered as the most necessary cooling technique.

During an operation, an application runtime occasionally becomes longer or shorter than previously measured runtime despite running under the same conditions (e.g., with the same load module and input parameters). We call this issue "runtime fluctuation".

The runtime fluctuations disturb efficient operations of the K computer. If runtime exceeds the maximum elapsed time given by a job script, the computational resources will be uselessly consumed due to the incomplete termination of the program. And if runtime is getting short, the job running order should be disordered and rearranged by the job scheduler.

Therefore, Operations and Computer Technologies Division (運用技術部門) continued to investigate these issues and resolve them. In this talk, I will show some cases of the runtime fluctuations and solutions.

ポストペタ時代の計算資源は、アプリケーションに対し、現状に比べさらに数桁上の並列性を要求する見通しです。そのような中、時間軸を新しい並列軸として利用する時間並列計算法が期待されています。時間方向での並列化は早い時期から期待されてきたのですが、その取組みの困難さから技術の進歩は遅い状況でした。ところが、2001年にParareal 法が提案されて以降、研究開発が活発となりました。Parareal法も多くの問題を抱えていましたが、ここ10年でその問題の解決の方向も明らかになりつつあります。また、多重スケール、カオス系、最適化手法等の異分野からの研究も活発化しています。そのため、時間並列計算法の研究開発は急速に進んでいる状況です。そこで、本講演では研究開発動向、応用分野、必要とされる技術等の観点から時間並列計算法の概要を説明し、また今後の発展の方向を述べたいと思います。

In recent years, a variational methods called tensor network methods have been widely applied to obtaining partition functions of classical statistical models or low-energy states of quantum many-body systems. One of the best example is the success of the density matrix renormalization group for many-body systems. In this presentation, I would like to introduce some features of typical tensor network methods and discuss potential bottleneck points in large-scale parallel computations of the tensor network methods.

Scientific data nowadays can contain various physical quantities, attracting researchers and engineers. Although multivariate high resolution simulation has become popular thanks to HPC architectures, even experts struggle to analyze and visualize the complex correlations between different quantities in their data. Our new data analysis web app, fiber surface GUI, eases such analysis for multivariate 3D data. You merely need to specify the region of interest in the familiar scatterplot in your web browser, and the server running in an interactive HPC environment extracts the distribution in the 3D space as 2D surfaces, as known as fiber surface, just as one would extract isosurfaces from 3D scalar data. Hence, importantly, an affordable computer with a weak performance can visualize and even analyze the output - fiber surface is smaller than the original 3D data for an order of magnitude when we compare the data size. In the talk, I introduce fiber surface, its GUI, and HIVE. HIVE is our visualization framework that systematizes your visualization workflow combining supercomputers and visualization-oriented clusters. I demonstrate how you can access the fiber surface GUI and HIVE for your research tasks. I will highly welcome assistance requests for your visualization tasks, as well as offers for new directions.

On the verge of the convergence between high performance computing (HPC) and Big Data processing, it has become increasingly prevalent to deploy large-scale data analytics workloads on high-end supercomputers. Such applications often come in the form of complex work- flows with various different components, assimilating data from scientific simulations as well as from measurements streamed from sensor net- works, such as radars and satellites. For example, as part of the next generation flagship (post-K) supercomputer project of Japan, RIKEN is investigating the feasibility of a highly accurate weather forecasting system that would provide a real-time outlook for severe guerrilla rainstorms. One of the main performance bottlenecks of this application is the lack of efficient communication among workflow components, which currently takes place over the parallel file system. This presentation reports an initial study of a direct communication framework designed for complex workflows that eliminates unnecessary file I/O among components. Specifically, we propose an I/O arbitrator layer that provides direct parallel data transfer among job components that rely on the netCDF interface for performing I/O operations, with only minimal modifications to application code. We present the design and a preliminary evaluation of the framework on the K Computer using RIKEN’s experimental weather forecasting workflow as a case study.

本講演では、分子の光化学―電子励起状態でおこるさまざまな過程―をab initio電子状態計算にもとづき理解することを目指す。特に、ポテンシャルエネルギー面の交差に注目して議論する。これらの交差は、電子状態間の遷移や基底状態への速やかな緩和など光化学において 非常に重要な役割を果たしている。現在の分子シミュレーション計算でどこまで明らかにできるのか述べたいと思う。

The solvers for dense eigenvalue problems are widely used in computational science applications. In the first half of this talk, we will briefly introduce techniques used in the solvers. In the latter half, some topics related to generalized eigensolvers will be presented.

本講演では、MPI-3 における主要な片側通信呼出しを紹介するとともに、FX100 でのプロトタイプ版の片側通信実装の性能結果を示します。

We are exploring new algorithms to construct biomolecular structures from coherent diffraction patterns of a single particle observed by X-ray free electron laser (XFEL). Coherent diffraction patterns contain useful information on bimolecular conformations. However, the　actual intensity on coherent diffraction pattern from a single particle is very weak. We need to extract useful signal from noisy data. I pay attention to develop and improve an algorithm to detect similarity between pairs of coherent diffraction patterns from an orientation-unknown single particle to extract useful information from noisy data [1,2].
This similarity detection algorithm for noisy diffraction patterns is extremely useful for single particle imaging. For example, this detection is an important step towards classification of a large number of experimental coherent diffraction patterns for reconstructing three dimensional structure of the molecule [1]. For another example, the detection algorithm plays an important role in a hybrid method using computational algorithms to generate hypothetical structural models for searching best agreement with limited experimental data [3].
Improvement of the similarity detection algorithm allows us to reduce the incident beam intensity, thus enabling to alleviate the radiation damage of sample during data acquisition [4,5].
In the presentation, I would like to talk about the possibility of single particle diffraction imaging using XFEL via attainable resolution as a function of the necessary incident beam intensity according to improved similarity detection algorithm.

[1] Tokuhisa, A., Taka, J., Kono, H., Go, N., 2012. Classifying and assembling two-dimensional X-ray laser diffraction patterns of a single particle to reconstruct the three-dimensional diffraction intensity function: Resolution limit due to the quantum noise. Acta Crystallogr. Sect. A Found. Crystallogr. 68, 366–381.
[2] Tokuhisa, A., Arai, J., Joti, Y., Ohno, Y., Kameyama, T., Yamamoto, K., Hatanaka, M., Gerofi, B., Shimada, A., Kurokawa, M., Shoji, F., Okada, K., Sugimoto, T., Yamaga, M., Tanaka, R., Yokokawa, M., Hori, A., Ishikawa, Y., Hatsui, T., Go, N., 2013. High-speed classification of coherent X-ray diffraction patterns on the K computer for high-resolution single biomolecule imaging. J. Synchrotron Radiat. 20, 899–904.
[3] Tokuhisa, A., Jonic, S., Tama, F., & Miyashita, O. 2016. Hybrid Approach for Structural Modeling of Biological Systems from X-ray Free Electron Laser Diffraction Patterns. Journal of structural biology.(in press)
[4] Kai, T., Tokuhisa, A., Moribayashi, K., Fukuda, Y., Kono, H., & Go, N. (2014). Intensity of Diffracted X-rays from Biomolecules with Radiation Damage Caused by Strong X-ray Pulses. Journal of the Physical Society of Japan, 83(9), 094301.
[5] Kai, T., Tokuhisa, A., & Kono, H. 2013. Calculation of Molecular-Structure-Based Damage Caused by Short-Pulse High-Intensity X-ray Lasers. Journal of the Physical Society of Japan, 82(11), 114301.