GPU-based Online Track Reconstruction for the ALICE TPC in Run 3 with Continuous Read-Out

In LHC Run 3, ALICE will increase the data taking rate significantly to 50 kHz continuous read-out of minimum bias Pb-Pb collisions. The reconstruction strategy of the online-offline computing upgrade foresees a first synchronous online reconstruction stage during data taking enabling detector calibration and data compression, and a posterior calibrated asynchronous reconstruction stage. Many new challenges arise, among them continuous TPC read-out, more overlapping collisions, no a priori knowledge of the primary vertex and of location-dependent calibration in the synchronous phase, identification of low-momentum looping tracks, and sophisticated raw data compression. The tracking algorithm for the Time Projection Chamber (TPC) will be based on a Cellular Automaton and the Kalman filter. The reconstruction shall run online, processing 50 times more collisions per second than today, while yielding results comparable to current offline reconstruction. Our TPC track finding leverages the potential of hardware accelerators via the OpenCL and CUDA APIs in a shared source code for CPUs and GPUs for both reconstruction stages. We give an overview of the status of Run 3 tracking including performance on processors and GPUs and achieved compression ratios.Comment: 8 pages, 7 figures, contribution to CHEP 2018 conferenc

The materiality of digital media: The hard disk drive, phonograph, magnetic tape and optical media in technical close-up

Popular discourses surrounding contemporary digital media often misrepresent it as immaterial and ephemeral, overlooking the material devices that store and generate our media objects. This article materially ‘descends’ into a selection of prior media forms that make up the genealogy of the hard disk drive (HDD) to challenge our reliance on conceptual misrepresentations. This material analysis is used to situate digital media in a genealogy of prior media forms, to enrich our understanding of how media’s affordances arise from the interplay of both formal and forensic materiality and to demonstrate the value of reintegrating materiality back into the study of media

Graphene-based flexible sensors towards electronic wearables

Flexible electronics and wearable devices have attracted considerable attention because they produce mechanical liberty, in terms of flexibility and stretchability that can enable the possibility of a wide range of new applications. The term “wearable electronics” can be used to define devices that can be worn or mated with the sensed surface to continuously monitor signals without limitations on mechanical deformability of the devices and electronic performance of the functional materials. The use of polymeric substrates or other nonconventional substrates as base materials brings novel functionalities to sensors and other electronic devices in terms of being flexible and light weight. Conductive nanomaterials, such as carbon nanotubes and graphene have been utilized as functional materials for flexible electronics and wearable devices. Graphene has specifically been considered for producing next-generation sensors due to its impressive electrical and mechanical properties and a result, incorporation of flexible substrates and graphene-based nanomaterials has been widely utilized to form versatile flexible sensors and other wearable devices through use of different fabrication processes. Creation of a large-scale, simple, high-resolution and cost-effective technique that overcomes fabrication limitations and supports production of flexible graphene-based sensors with high flexibility and stretch ability is highly demanding. Soft lithography can be merged with a mechanical exfoliation process using adhesive tape followed by transfer printing to form a graphene sensor on a desired final substrate. In situ microfluidic casting of graphene into channels is another promising platform driving the rapid development of flexible graphene sensors and wearable devices with a wide dynamic detection range. Selective coating of graphene-based nanomaterials (e.g. graphene oxide (GO)) on flexible electrode tapes can, because of its flexibility and adhesive features, be used to track relative humidity (RH) variations at the surface of target surfaces. This thesis describes the design and development of flexible and wearable strain, pressure and humidity sensors based on a novel tape-based cost-effective patterning and transferring technique, an in situ microfluidic casting method, and a novel selective coating technique for graphene-based nanomaterials. First of all, we present a tape-based graphene patterning and transferring approach to production of graphene sensors on elastomeric substrates and adhesive tapes. The method utilizes the work of adhesion at the interface between two contacting materials as determined by their surface energies to pattern graphene on PDMS substrate and transfer it onto a target tape. We have achieved patterning and transferring method with the features of high pattern spatial resolution, thickness control, and process simplicity with respect to functional materials and pattern geometries. We have demonstrated the usage of flexible graphene sensors on tape to realize interaction with structures, humans, and plants for real-time monitoring of important signals. Secondly, we present a helical spring-like piezo resistive graphene sensor formed within a microfluidic channel using a unique and easy in situ microfluidic casting method. Because of its helical shape, the sensor exhibits a wide dynamic detection range as well as mechanical flexibility and stretch ability. Finally, we present a flexible GO-based RH sensor on an adhesive polyimide thin film realized by selectively coating and patterning GO at the surface of Au Interdigitated electrodes (IDEs) and subsequently peeling the device from a temporary PDMS film. Real-time monitoring of the water movement inside the plant has been demonstrated by installing GO-based RH sensor at the surfaces of different plant leaves

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

Towards Tamper-Evident Storage on Patterned Media

We propose a tamper-evident storage system based on probe storage with a patterned magnetic medium. This medium supports normal read/write operations by out-of-plane magnetisation of individual magnetic dots. We report on measurements showing that in principle the medium also supports a separate class of write-once operation that destroys the out-of-plane magnetisation property of the dots irreversibly by precise local heating. We discuss the main issues of designing a tamper-evident storage device and file system using the properties of the medium

Printing Conductive Paths for Electronic Functional Devices

Printing inorganic and organic materials has been attracting plenty of researchers and scientists as an alternative to the conventional photolithography and electroless deposition methods due to the complications, time-consuming, size restrictions and high costs that these methods usually experience. Soft lithographic techniques and inkjet printing technology have offered simpler, lower costs and faster alternatives. One of the main objectives of this study is the contribution to these alternatives by utilising a cost-effective, simple and easy-to-use stamp printing machine in the deposition of metal patterns from poly(dimethylsiloxane) (PDMS) stamps onto treated glass substrates. Two drop-on-demand inkjet printers; one is a commercial desktop piezoelectric printer and a second thermal PEL printing and coating platform, were utilised to inkjet print functional materials. The cheap piezoelectric one used to deposit silver nanoparticles and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) inks. By utilising this technology, innovative flexible information storage devices, electronic memory cells, were inkjet printed. All the components (silver electrodes and PEDOT:PSS active layer) of these memory devices were fully deposited by this simple desktop inkjet printer on a flexible substrate (ceramic coated PEL paper) at room temperature. The thermal printing machine, on the other hand, was employed to print graphene oxide on the PEL paper. These techniques also provide hope to develop environmentally friendly processes of fabrication used in the electronics and semiconductor industry and minimise the wastage of materials and power

The implementation of nanoimprint lithography for the fabrication of patterned magnetic media

Advances in technology are having profound effects throughout society. This is no truer than in the way information is being stored. The primary form of information storage for at least the past millennium has been paper. Today, an ever increasing amount of information is being stored electronically. An increased demand for high-performance, low-cost information storage has been a major catalyst in increasing the popularity of hard drives. In 2002, two exabytes of original information was stored on hard drives. This is ten times the amount of all printed material in the world if it were converted to electronic files. To keep up with this demand, the capacity of hard drives has increased by at least 60% annually since 1991. The capacity has mainly increased by scaling down the relevant dimensions much in the same way that has been done with microprocessors. Scaling cannot indefinitely be used to increase the capacity of hard drives that employ longitudinal magnetic recording. Before long, the superparamagnetic effect will limit the achievable information capacity of hard drives using conventional recording. Therefore, new technologies will be needed. Perpendicular recording, one of several new technologies, will make its entrance into the market later this year in a hard drive designed by Toshiba for Apple\u27s iPod music player. It is said that the hard drive will have an areal bit density of 133 Gbits/in2. This is an increase of 75% over what is currently available today. However, the hard drive will still employ a continuous magnetic medium. Even greater densities can be achieved if the magnetic medium is physically patterned into isolated bits. This technology, known as patterned magnetic media, has the potential of achieving areal bit densities greater than 1 Tbit/in2. The challenge is finding a way to fabricate it. A high-throughput, low-cost pattern generation technology is needed. Research completed with nanoimprint lithography demonstrates that it can be used to fabricate patterned magnetic media. Several patterns of magnetic media were fabricated with densely packed sub-20-nm features that would produce an areal bit density of at least 258 Gbits/in2

HD DVD substrates for surface enhanced Raman spectroscopy analysis : fabrication, theoretical predictions and practical performance

Commercial HD DVDs provide a characteristic structure of encoding pits which were utilized to fabricate cost efficiently large area SERS substrates for chemical analysis. The study targets the simulation of the plasmonic structure of the substrates and presents an easily accessible fabrication process to obtain highly sensitive SERS active substrates. The theoretical simulation predicted the formation of supermodes under optimized illumination conditions, which were verified experimentally. First tests of the developed SERS substrates demonstrated their excellent potential for detecting vitamin A and pro- vitamin A at low concentration levels