The SIOX architecture – coupling automatic monitoring and optimization of parallel I/O

Performance analysis and optimization of high-performance I/O systems is a daunting task. Mainly, this is due to the overwhelmingly complex interplay of the involved hardware and software layers. The Scalable I/O for Extreme Performance (SIOX) project provides a versatile environment for monitoring I/O activities and learning from this information. The goal of SIOX is to automatically suggest and apply performance optimizations, and to assist in locating and diagnosing performance problems. In this paper, we present the current status of SIOX. Our modular architecture covers instrumentation of POSIX, MPI and other high-level I/O libraries; the monitoring data is recorded asynchronously into a global database, and recorded traces can be visualized. Furthermore, we offer a set of primitive plug-ins with additional features to demonstrate the flexibility of our architecture: A surveyor plug-in to keep track of the observed spatial access patterns; an fadvise plug-in for injecting hints to achieve read-ahead for strided access patterns; and an optimizer plug-in which monitors the performance achieved with different MPI-IO hints, automatically supplying the best known hint-set when no hints were explicitly set. The presentation of the technical status is accompanied by a demonstration of some of these features on our 20 node cluster. In additional experiments, we analyze the overhead for concurrent access, for MPI-IO’s 4-levels of access, and for an instrumented climate application. While our prototype is not yet full-featured, it demonstrates the potential and feasibility of our approach

Monitoring energy consumption with SIOX

In the face of the growing complexity of HPC systems, their growing energy costs, and the increasing difficulty to run applications efficiently, a number of monitoring tools have been developed during the last years. SIOX is one such endeavor, with a uniquely holistic approach: Not only does it aim to record a certain kind of data, but to make all relevant data available for analysis and optimization. Among other sources, this encompasses data from hardware energy counters and trace data from different hardware/software layers. However, not all data that can be recorded should be recorded. As such, SIOX needs good heuristics to determine when and what data needs to be collected, and the energy consumption can provide an important signal about when the system is in a state that deserves closer attention. In this paper, we show that SIOX can use Likwid to collect and report the energy consumption of applications, and present how this data can be visualized using SIOX’s web-interface. Furthermore, we outline how SIOX can use this information to intelligently adjust the amount of data it collects, allowing it to reduce the monitoring overhead while still providing complete information about critical situations

Low Power Memory/Memristor Devices and Systems

This reprint focusses on achieving low-power computation using memristive devices. The topic was designed as a convenient reference point: it contains a mix of techniques starting from the fundamental manufacturing of memristive devices all the way to applications such as physically unclonable functions, and also covers perspectives on, e.g., in-memory computing, which is inextricably linked with emerging memory devices such as memristors. Finally, the reprint contains a few articles representing how other communities (from typical CMOS design to photonics) are fighting on their own fronts in the quest towards low-power computation, as a comparison with the memristor literature. We hope that readers will enjoy discovering the articles within

Journal of Telecommunications and Information Technology, 2010, nr 1

kwartalni

Biomimetic Based Applications

The interaction between cells, tissues and biomaterial surfaces are the highlights of the book "Biomimetic Based Applications". In this regard the effect of nanostructures and nanotopographies and their effect on the development of a new generation of biomaterials including advanced multifunctional scaffolds for tissue engineering are discussed. The 2 volumes contain articles that cover a wide spectrum of subject matter such as different aspects of the development of scaffolds and coatings with enhanced performance and bioactivity, including investigations of material surface-cell interactions

Space station WP-04 power system. Volume 2: Study results

Results of the phase B study contract for the definition of the space station Electric Power System (EPS) are presented in detail along with backup information and supporting data. Systems analysis and trades, preliminary design, advanced development, customer accommodations, operations planning, product assurance, and design and development phase planning are addressed. The station design is a hybrid approach which provides user power of 25 kWe from the photovoltaic subsystem and 50 kWe from the solar dynamic subsystem. The electric power is distributed to users as a utility service; single phase at a frequency of 20 kHz and voltage of 440VAC. The solar array NiH2 batteries of the photovoltaic subsystem are based on commonality to those used on the co-orbiting and solar platforms

Fourth Annual Workshop on Space Operations Applications and Research (SOAR 90)

The papers from the symposium are presented. Emphasis is placed on human factors engineering and space environment interactions. The technical areas covered in the human factors section include: satellite monitoring and control, man-computer interfaces, expert systems, AI/robotics interfaces, crew system dynamics, and display devices. The space environment interactions section presents the following topics: space plasma interaction, spacecraft contamination, space debris, and atomic oxygen interaction with materials. Some of the above topics are discussed in relation to the space station and space shuttle

Electrodeposited semiconductor nanostructures & epitaxial thin films for flexible electronics

Single-crystal Si is the bedrock of semiconductor devices due to the high crystalline perfection which minimizes electron-hole recombination, and the dense native silicon oxide which minimizes surface states. To expand the palette of electronic materials beyond planar Si, an inexpensive source of highly ordered material is needed that can serve as an inert substrate for the epitaxial growth of grain boundary-free semiconductors, photonic materials, and superconductors. There is also a need for a simple, inexpensive, and scalable fabrication technique for the growth of semiconductor nanostructures and thin films. This dissertation focuses on the fabrication of semiconducting nanowires (polycrystalline Ge & epitaxial ZnO) and epitaxial thin films (Au & Cu₂O) using electrodeposition from an aqueous solution at ambient conditions as a simple benchtop process. Paper I describes a simple one-step electrodeposition of Ge nanowires on an indium-tin oxide substrate decorated with In nanoparticles. An In metal acts both as a catalyst for electrodeposition and as a solvent for recrystallization of the nanowires at ambient conditions. Ge nanowires are an attractive anode material for Li-ion batteries, due to their larger theoretical capacity compared to graphite. Paper II presents a scheme for epitaxial electrodeposition of ultrathin Au films on Si as an inexpensive proxy for single crystal Au for the electrodeposition of epitaxial Cu₂O thin films. A detailed study of the epitaxial growth, morphology, junction characteristics, and crystallinity is performed for both the Au and Cu₂O thin films. Paper III describes a technique for epitaxial lift-off of wafer-scale Au foils as transparent, single-crystal and flexible substrates for flexible electronics. The Au foils offer the order of traditional single-crystal semiconductors without the constraint of a rigid substrate. An organic light emitting diode is presented to evaluate the flexibility and transparency of Au foils. To study the single crystal nature of Au foil an epitaxial Cu₂O thin film inorganic diode with an improved diode quality factor is demonstrated --Abstract, page iv