Simulation of hierarchical storage systems for TCO and QoS

Due to the variety of storage technologies deep storage hierarchies turn out to be the most feasible choice to meet performance and cost requirements when handling vast amounts of data. Long-term archives employed by scientific users are mainly reliant on tape storage, as it remains the most cost-efficient option. Archival systems are often loosely integrated into the HPC storage infrastructure. In expectation of exascale systems and in situ analysis also burst buffers will require integration with the archive. Exploring new strategies and developing open software for tape systems is a hurdle due to the lack of affordable storage silos and availability outside of large organizations and due to increased wariness requirements when dealing with ultra-durable data. Lessening these problems by providing virtual storage silos should enable community-driven innovation and enable site operators to add features where they see fit while being able to verify strategies before deploying on production systems. Different models for the individual components in tape systems are developed. The models are then implemented in a prototype simulation using discrete event simulation. The work shows that the simulations can be used to approximate the behavior of tape systems deployed in the real world and to conduct experiments without requiring a physical tape system

Implementing and Evaluating Jukebox Schedulers Using JukeTools

Scheduling jukebox resources is important to build efficient and flexible hierarchical storage systems. JukeTools is a toolbox that helps in the complex tasks of implementing and evaluating jukebox schedulers. It allows the fast development of jukebox schedulers. The schedulers can be tested in numerous environments, both real and simulated types. JukeTools helps the developer to easily detect errors in the schedules. Analyzer tools create detailed reports on the behavior and performance of any of the scheduler, and provide comparisons between different schedulers. This paper describes the functionality offered by JukeTools, with special emphasis on how the toolbox can be used to develop jukebox schedulers

Inductance modeling and extraction in EMC applications

Inductance has become a challenging problem for EMC engineers in many applications. Regardless of the application at hand, the first step remains the same; return to the physics and trace the current paths. IGBTs have become an important part in the design of power electronics because of their ability to switch fast and with stand high currents. Modules used for three phase motor drives often create problems when neglected parasitic components show themselves and interfere with the performance of the desired operation of a system. Many manufactures of these modules do not give out equivalent circuit modules and therefore leave a black box for this part of the designers schematic used in simulations. When these systems include motors, other problems can arise which may require their own consideration. Pre-emphasis is a method used to reduce the attenuation of a signal as it travels from one end of a transmission line to another by boosting frequency components of a signal. In order for this method to work, it is important to know how the impedance changes across the board. Working with the capacitances is relatively easy, while revealing the inductance and pin pointing it on the geometry often creates a challenge. Strong magnetic fields are desired for high energy delivering systems where full-wave modeling plays a crucial role in the design of superior systems. The inductance associated with the geometry must be distributed properly for the development of a system that maximizes the fields. This is accomplished by following the current paths and focusing on the physics involved --Abstract, page iii

Sixth Goddard Conference on Mass Storage Systems and Technologies Held in Cooperation with the Fifteenth IEEE Symposium on Mass Storage Systems

This document contains copies of those technical papers received in time for publication prior to the Sixth Goddard Conference on Mass Storage Systems and Technologies which is being held in cooperation with the Fifteenth IEEE Symposium on Mass Storage Systems at the University of Maryland-University College Inn and Conference Center March 23-26, 1998. As one of an ongoing series, this Conference continues to provide a forum for discussion of issues relevant to the management of large volumes of data. The Conference encourages all interested organizations to discuss long term mass storage requirements and experiences in fielding solutions. Emphasis is on current and future practical solutions addressing issues in data management, storage systems and media, data acquisition, long term retention of data, and data distribution. This year's discussion topics include architecture, tape optimization, new technology, performance, standards, site reports, vendor solutions. Tutorials will be available on shared file systems, file system backups, data mining, and the dynamics of obsolescence

Modular MRI Guided Device Development System: Development, Validation and Applications

Since the first robotic surgical intervention was performed in 1985 using a PUMA industrial manipulator, development in the field of surgical robotics has been relatively fast paced, despite the tremendous costs involved in developing new robotic interventional devices. This is due to the clear advantages to augmented a clinicians skill and dexterity with the precision and reliability of computer controlled motion. A natural extension of robotic surgical intervention is the integration of image guided interventions, which give the promise of reduced trauma, procedure time and inaccuracies. Despite magnetic resonance imaging (MRI) being one of the most effective imaging modalities for visualizing soft tissue structures within the body, MRI guided surgical robotics has been frustrated by the high magnetic field in the MRI image space and the extreme sensitivity to electromagnetic interference. The primary contributions of this dissertation relate to enabling the use of direct, live MR imaging to guide and assist interventional procedures. These are the two focus areas: creation both of an integrated MRI-guided development platform and of a stereotactic neural intervention system. The integrated series of modules of the development platform represent a significant advancement in the practice of creating MRI guided mechatronic devices, as well as an understanding of design requirements for creating actuated devices to operate within a diagnostic MRI. This knowledge was gained through a systematic approach to understanding, isolating, characterizing, and circumventing difficulties associated with developing MRI-guided interventional systems. These contributions have been validated on the levels of the individual modules, the total development system, and several deployed interventional devices. An overview of this work is presented with a summary of contributions and lessons learned along the way

Design fabrication and calibration of MEMS actuators for in-situ materials testing

Many MEMS devices utilize thin metallic films as mechanical structures. The elastic and plastic properties of these thin films (thickness \u3c 1μm) are significantly different from those of the bulk material. At these scales the volume fraction of material defects such as: grain boundaries, dislocations and interstitials become quite significant and become a chief contributor the physical and mechanical material properties of the thin films. Aluminum (Al), Copper (Cu), Nickel (Ni) and Gold (Au) are popular thin film materials used in MEMS/NEMS. Various studies have been conducted in recent years to study the mechanical properties of freestanding thin films in situ in TEM to study their failure mechanisms. Some of these studies utilize MEMS devices as actuators. These actuators are often co-fabricated with the specimen being tested therefore limiting the type of specimen that could be tested. Also these MEMS actuators are almost never traceably calibrated and their response is calculated. This thesis describes the design and fabrication process of a MEMS actuator for materials testing in-situ in TEM. The actuator is fabricated independent of the specimen. A setup was designed to calibrate these devices with a method that can be traced back to NIST standards. It has been shown that the calibrated response of these MEMS actuators is different from its calculated response and the use of un-calibrated devices for materials testing can lead to misleading results

NASA SBIR abstracts of 1991 phase 1 projects

The objectives of 301 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1991 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 301, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1991 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included

In-Space technology experiments program. A high efficiency thermal interface (using condensation heat transfer) between a 2-phase fluid loop and heatpipe radiator: Experiment definition phase

Space Station elements and advanced military spacecraft will require rejection of tens of kilowatts of waste heat. Large space radiators and two-phase heat transport loops will be required. To minimize radiator size and weight, it is critical to minimize the temperature drop between the heat source and sink. Under an Air Force contract, a unique, high-performance heat exchanger is developed for coupling the radiator to the transport loop. Since fluid flow through the heat exchanger is driven by capillary forces which are easily dominated by gravity forces in ground testing, it is necessary to perform microgravity thermal testing to verify the design. This contract consists of an experiment definition phase leading to a preliminary design and cost estimate for a shuttle-based flight experiment of this heat exchanger design. This program will utilize modified hardware from a ground test program for the heat exchanger

Process parameter modeling for nanocrystalline ceria based thin films prepared via aerosol jet printing

Solid Oxide Fuel Cells (SOFCs) are becoming a popular choice for meeting energy requirements of the present day due to their high efficiency and reformation capabilities. SOFCs are made of ceramic oxides with well-defined physical and thermal properties enabling a high operating temperature range (600-800°C). Efficiency of a SOFC is typically well represented by its output voltage. Resistances across various compo- nents of the SOFC viz. anode, electrolyte and cathode diminish the maximum output voltage thus directly affecting the efficiency of the fuel cell. Each of the layers in a SOFC has generic as well as specific re- quirements warranting specialized fabrication processes. While such processes are many in number, they face limitations on size of the particles usable for the process, cost, ability to create graded porosity, thick- ness, etc. The main thrust of this work is the employment of a novel direct-write tool, namely the Optomec Aerosol Jet deposition system for fabricating the electrolyte layer of a SOFC that addresses some of the practical limitations of traditional SOFC fabrication techniques. While Optomec\u27s Aerosol Jet deposition technique has been employed in several applications including printed electronics, a structured approach to identifying process parameters for printing materials was not found in literature. This work identifies and models process parameters significant to the deposition of nano- crystalline ceria with thickness of the deposited layer as response variable through design of experiments. Initial feasibility tests determined printability of the test ink and established a working range for the desired process parameters under investigation. A full factorial design with five factors and two levels was executed as the screening design. Three of five factors were determined as significant from the screening experiments. A regression equation was generated with the three significant terms from screening. Validation runs exe- cuted indicated lack of curvature within the design space for the significant parameters. Coefficients of terms from the regression equation were updated after regression analysis of a higher order design of experiments with three levels and the three significant parameters from screening. The updated regression equation provides a model with a reduced standard error and better fit of residuals as compared to the model from screening. A brief study on drying methods post-deposition and its impact on the quality of the printed film is also presented in this work