50 research outputs found
Real-Time Trigger and online Data Reduction based on Machine Learning Methods for Particle Detector Technology
Moderne Teilchenbeschleuniger-Experimente generieren während zur Laufzeit immense Datenmengen. Die gesamte erzeugte Datenmenge abzuspeichern, überschreitet hierbei schnell das verfügbare Budget für die Infrastruktur zur Datenauslese. Dieses Problem wird üblicherweise durch eine Kombination von Trigger- und Datenreduktionsmechanismen adressiert. Beide Mechanismen werden dabei so nahe wie möglich an den Detektoren platziert um die gewünschte Reduktion der ausgehenden Datenraten so frühzeitig wie möglich zu ermöglichen. In solchen Systeme traditionell genutzte Verfahren haben währenddessen ihre Mühe damit eine effiziente Reduktion in modernen Experimenten zu erzielen. Die Gründe dafür liegen zum Teil in den komplexen Verteilungen der auftretenden Untergrund Ereignissen. Diese Situation wird bei der Entwicklung der Detektorauslese durch die vorab unbekannten Eigenschaften des Beschleunigers und Detektors während des Betriebs unter hoher Luminosität verstärkt. Aus diesem Grund wird eine robuste und flexible algorithmische Alternative benötigt, welche von Verfahren aus dem maschinellen Lernen bereitgestellt werden kann. Da solche Trigger- und Datenreduktion-Systeme unter erschwerten Bedingungen wie engem Latenz-Budget, einer großen Anzahl zu nutzender Verbindungen zur Datenübertragung und allgemeinen Echtzeitanforderungen betrieben werden müssen, werden oft FPGAs als technologische Basis für die Umsetzung genutzt. Innerhalb dieser Arbeit wurden mehrere Ansätze auf Basis von FPGAs entwickelt und umgesetzt, welche die vorherrschenden Problemstellungen für das Belle II Experiment adressieren. Diese Ansätze werden über diese Arbeit hinweg vorgestellt und diskutiert werden
Commissioning Perspectives for the ATLAS Pixel Detector
The ATLAS Pixel Detector, the innermost sub-detector of the ATLAS experiment at the Large Hadron Collider, CERN, is an 80 million channel silicon pixel tracking detector designed for high-precision charged particle tracking and secondary vertex reconstruction. It was installed in the ATLAS experiment and commissioning for the first proton-proton collision data taking in 2008 has begun. Due to the complex layout and limited accessibility, quality assurance measurements were continuously performed during production and assembly to ensure that no problematic components are integrated. The assembly of the detector at CERN and related quality assurance measurement results, including comparison to previous production measurements, will be presented. In order to verify that the integrated detector, its data acquisition readout chain, the ancillary services and cooling system as well as the detector control and data acquisition software perform together as expected approximately 8% of the detector system was progressively assembled as close to the final layout as possible. The so-called System Test laboratory setup was operated for several months under experiment-like environment conditions. The interplay between different detector components was studied with a focus on the performance and tunability of the optical data transmission system. Operation and optical tuning procedures were developed and qualified for the upcoming commission ing. The front-end electronics preamplifier threshold tuning and noise performance were studied and noise occupancy of the detector with low sensor bias voltages was investigated. Data taking with cosmic muons was performed to test the data acquisition and trigger system as well as the offline reconstruction and analysis software. The data quality was verified with an extended version of the pixel online monitoring package which was implemented for the ATLAS Combined Testbeam. The detector raw data of the Combined Testbeam and of the System Test cosmic run was converted for offline data analysis with the Pixel bytestream converter which was continuously extended and adapted according to the offline analysis software needs
A Sustainable Autonomic Architecture for Organically Reconfigurable Computing Systems
A Sustainable Autonomic Architecture for Organically Reconfigurable Computing System based on SRAM Field Programmable Gate Arrays (FPGAs) is proposed, modeled analytically, simulated, prototyped, and measured. Low-level organic elements are analyzed and designed to achieve novel self-monitoring, self-diagnosis, and self-repair organic properties. The prototype of a 2-D spatial gradient Sobel video edge-detection organic system use-case developed on a XC4VSX35 Xilinx Virtex-4 Video Starter Kit is presented. Experimental results demonstrate the applicability of the proposed architecture and provide the infrastructure to quantify the performance and overcome fault-handling limitations. Dynamic online autonomous functionality restoration after a malfunction or functionality shift due to changing requirements is achieved at a fine granularity by exploiting dynamic Partial Reconfiguration (PR) techniques. A Genetic Algorithm (GA)-based hardware/software platform for intrinsic evolvable hardware is designed and evaluated for digital circuit repair using a variety of well-accepted benchmarks. Dynamic bitstream compilation for enhanced mutation and crossover operators is achieved by directly manipulating the bitstream using a layered toolset. Experimental results on the edge-detector organic system prototype have shown complete organic online refurbishment after a hard fault. In contrast to previous toolsets requiring many milliseconds or seconds, an average of 0.47 microseconds is required to perform the genetic mutation, 4.2 microseconds to perform the single point conventional crossover, 3.1 microseconds to perform Partial Match Crossover (PMX) as well as Order Crossover (OX), 2.8 microseconds to perform Cycle Crossover (CX), and 1.1 milliseconds for one input pattern intrinsic evaluation. These represent a performance advantage of three orders of magnitude over the JBITS software framework and more than seven orders of magnitude over the Xilinx design flow. Combinatorial Group Testing (CGT) technique was combined with the conventional GA in what is called CGT-pruned GA to reduce repair time and increase system availability. Results have shown up to 37.6% convergence advantage using the pruned technique. Lastly, a quantitative stochastic sustainability model for reparable systems is formulated to evaluate the Sustainability of FPGA-based reparable systems. This model computes at design-time the resources required for refurbishment to meet mission availability and lifetime requirements in a given fault-susceptible missions. By applying this model to MCNC benchmark circuits and the Sobel Edge-Detector in a realistic space mission use-case on Xilinx Virtex-4 FPGA, we demonstrate a comprehensive model encompassing the inter-relationships between system sustainability and fault rates, utilized, and redundant hardware resources, repair policy parameters and decaying reparability
Content-Aware Multimedia Communications
The demands for fast, economic and reliable dissemination of multimedia
information are steadily growing within our society. While people and
economy increasingly rely on communication technologies, engineers still
struggle with their growing complexity.
Complexity in multimedia communication originates from several sources. The
most prominent is the unreliability of packet networks like the Internet.
Recent advances in scheduling and error control mechanisms for streaming
protocols have shown that the quality and robustness of multimedia delivery
can be improved significantly when protocols are aware of the content they
deliver. However, the proposed mechanisms require close cooperation between
transport systems and application layers which increases the overall system
complexity. Current approaches also require expensive metrics and focus on
special encoding formats only. A general and efficient model is missing so
far.
This thesis presents efficient and format-independent solutions to support
cross-layer coordination in system architectures. In particular, the first
contribution of this work is a generic dependency model that enables
transport layers to access content-specific properties of media streams,
such as dependencies between data units and their importance. The second
contribution is the design of a programming model for streaming
communication and its implementation as a middleware architecture. The
programming model hides the complexity of protocol stacks behind simple
programming abstractions, but exposes cross-layer control and monitoring
options to application programmers. For example, our interfaces allow
programmers to choose appropriate failure semantics at design time while
they can refine error protection and visibility of low-level errors at
run-time.
Based on some examples we show how our middleware simplifies the
integration of stream-based communication into large-scale application
architectures. An important result of this work is that despite cross-layer
cooperation, neither application nor transport protocol designers
experience an increase in complexity. Application programmers can even
reuse existing streaming protocols which effectively increases system
robustness.Der Bedarf unsere Gesellschaft nach kostengünstiger und
zuverlässiger
Kommunikation wächst stetig. Während wir uns selbst immer mehr von modernen
Kommunikationstechnologien abhängig machen, müssen die Ingenieure dieser
Technologien sowohl den Bedarf nach schneller Einführung neuer Produkte
befriedigen als auch die wachsende Komplexität der Systeme beherrschen.
Gerade die Übertragung multimedialer Inhalte wie Video und Audiodaten ist
nicht trivial. Einer der prominentesten Gründe dafür ist die
Unzuverlässigkeit heutiger Netzwerke, wie z.B.~dem Internet. Paketverluste
und schwankende Laufzeiten können die Darstellungsqualität massiv
beeinträchtigen. Wie jüngste Entwicklungen im Bereich der
Streaming-Protokolle zeigen, sind jedoch Qualität und Robustheit der
Übertragung effizient kontrollierbar, wenn Streamingprotokolle
Informationen über den Inhalt der transportierten Daten ausnutzen.
Existierende Ansätze, die den Inhalt von Multimediadatenströmen
beschreiben, sind allerdings meist auf einzelne Kompressionsverfahren
spezialisiert und verwenden berechnungsintensive Metriken. Das reduziert
ihren praktischen Nutzen deutlich. Außerdem erfordert der
Informationsaustausch eine enge Kooperation zwischen Applikationen und
Transportschichten. Da allerdings die Schnittstellen aktueller
Systemarchitekturen nicht darauf vorbereitet sind, müssen entweder die
Schnittstellen erweitert oder alternative Architekturkonzepte geschaffen
werden. Die Gefahr beider Varianten ist jedoch, dass sich die Komplexität
eines Systems dadurch weiter erhöhen kann.
Das zentrale Ziel dieser Dissertation ist es deshalb,
schichtenübergreifende Koordination bei gleichzeitiger Reduzierung der
Komplexität zu erreichen. Hier leistet die Arbeit zwei Beträge zum
aktuellen Stand der Forschung. Erstens definiert sie ein universelles
Modell zur Beschreibung von Inhaltsattributen, wie Wichtigkeiten und
Abhängigkeitsbeziehungen innerhalb eines Datenstroms. Transportschichten
können dieses Wissen zur effizienten Fehlerkontrolle verwenden. Zweitens
beschreibt die Arbeit das Noja Programmiermodell für multimediale
Middleware. Noja definiert Abstraktionen zur Übertragung und Kontrolle
multimedialer Ströme, die die Koordination von Streamingprotokollen mit
Applikationen ermöglichen. Zum Beispiel können Programmierer geeignete
Fehlersemantiken und Kommunikationstopologien auswählen und den konkreten
Fehlerschutz dann zur Laufzeit verfeinern und kontrolliere
Accelerating Network Functions using Reconfigurable Hardware. Design and Validation of High Throughput and Low Latency Network Functions at the Access Edge
Providing Internet access to billions of people worldwide is one of the main technical challenges in the current decade. The Internet access edge connects each residential and mobile subscriber to this network and ensures a certain Quality of Service (QoS). However, the implementation of access edge functionality challenges Internet service providers: First, a good QoS must be provided to the subscribers, for example, high throughput and low latency. Second, the quick rollout of new technologies and functionality demands flexible configuration and programming possibilities of the network components; for example, the support of novel, use-case-specific network protocols. The functionality scope of an Internet access edge requires the use of programming concepts, such as Network Functions Virtualization (NFV). The drawback of NFV-based network functions is a significantly lowered resource efficiency due to the execution as software, commonly resulting in a lowered QoS compared to rigid hardware solutions. The usage of programmable hardware accelerators, named NFV offloading, helps to improve the QoS and flexibility of network function implementations.
In this thesis, we design network functions on programmable hardware to improve the QoS and flexibility. First, we introduce the host bypassing concept for improved integration of hardware accelerators in computer systems, for example, in 5G radio access networks. This novel concept bypasses the system’s main memory and enables direct connectivity between the accelerator and network interface card. Our evaluations show an improved throughput and significantly lowered latency jitter for the presented approach. Second, we analyze different programmable hardware technologies for hardware-accelerated Internet subscriber handling, including three P4-programmable platforms and FPGAs. Our results demonstrate that all approaches have excellent performance and are suitable for Internet access creation. We present a fully-fledged User Plane Function (UPF) designed upon these concepts and test it in an end-to-end 5G standalone network as part of this contribution. Third, we analyze and demonstrate the usability of Active Queue Management (AQM) algorithms on programmable hardware as an expansion to the access edge. We show the feasibility of the CoDel AQM algorithm and discuss the challenges and constraints to be considered when limited hardware is used. The results show significant improvements in the QoS when the AQM algorithm is deployed on hardware.
Last, we focus on network function benchmarking, which is crucial for understanding the behavior of implementations and their optimization, e.g., Internet access creation. For this, we introduce the load generation and measurement framework P4STA, benefiting from flexible software-based load generation and hardware-assisted measuring. Utilizing programmable network switches, we achieve a nanosecond time accuracy while generating test loads up to the available Ethernet link speed
Mu2e Technical Design Report
The Mu2e experiment at Fermilab will search for charged lepton flavor
violation via the coherent conversion process mu- N --> e- N with a sensitivity
approximately four orders of magnitude better than the current world's best
limits for this process. The experiment's sensitivity offers discovery
potential over a wide array of new physics models and probes mass scales well
beyond the reach of the LHC. We describe herein the preliminary design of the
proposed Mu2e experiment. This document was created in partial fulfillment of
the requirements necessary to obtain DOE CD-2 approval.Comment: compressed file, 888 pages, 621 figures, 126 tables; full resolution
available at http://mu2e.fnal.gov; corrected typo in background summary,
Table 3.
Nova combinação de hardware e de software para veículos de desporto automóvel baseada no processamento directo de funções gráficas
Doutoramento em Engenharia EletrónicaThe main motivation for the work presented here began with previously
conducted experiments with a programming concept at the time named
"Macro". These experiments led to the conviction that it would be possible to
build a system of engine control from scratch, which could eliminate many of
the current problems of engine management systems in a direct and intrinsic
way. It was also hoped that it would minimize the full range of software and
hardware needed to make a final and fully functional system.
Initially, this paper proposes to make a comprehensive survey of the state of
the art in the specific area of software and corresponding hardware of
automotive tools and automotive ECUs. Problems arising from such software
will be identified, and it will be clear that practically all of these problems stem
directly or indirectly from the fact that we continue to make comprehensive use
of extremely long and complex "tool chains". Similarly, in the hardware, it will
be argued that the problems stem from the extreme complexity and
inter-dependency inside processor architectures. The conclusions are
presented through an extensive list of "pitfalls" which will be thoroughly
enumerated, identified and characterized.
Solutions will also be proposed for the various current issues and for the
implementation of these same solutions. All this final work will be part of a
"proof-of-concept" system called "ECU2010". The central element of this
system is the before mentioned "Macro" concept, which is an graphical block
representing one of many operations required in a automotive system having
arithmetic, logic, filtering, integration, multiplexing functions among others. The
end result of the proposed work is a single tool, fully integrated, enabling the
development and management of the entire system in one simple visual
interface. Part of the presented result relies on a hardware platform fully
adapted to the software, as well as enabling high flexibility and scalability in
addition to using exactly the same technology for ECU, data logger and
peripherals alike.
Current systems rely on a mostly evolutionary path, only allowing online
calibration of parameters, but never the online alteration of their own
automotive functionality algorithms. By contrast, the system developed and
described in this thesis had the advantage of following a "clean-slate"
approach, whereby everything could be rethought globally. In the end, out of all
the system characteristics, "LIVE-Prototyping" is the most relevant feature,
allowing the adjustment of automotive algorithms (eg. Injection, ignition,
lambda control, etc.) 100% online, keeping the engine constantly working,
without ever having to stop or reboot to make such changes. This consequently
eliminates any "turnaround delay" typically present in current automotive
systems, thereby enhancing the efficiency and handling of such systems.A principal motivação para o trabalho que conduziu a esta tese residiu na
constatação de que os actuais métodos de modelação de centralinas
automóveis conduzem a significativos problemas de desenvolvimento e
manutenção. Como resultado dessa constatação, o objectivo deste trabalho
centrou-se no desenvolvimento de um conceito de arquitectura que rompe
radicalmente com os modelos state-of-the-art e que assenta num conjunto de
conceitos que vieram a ser designados de "Macro" e "Celular ECU". Com este
modelo pretendeu-se simultaneamente minimizar a panóplia de software e de
hardware necessários à obtenção de uma sistema funcional final.
Inicialmente, esta tese propõem-se fazer um levantamento exaustivo do
estado da arte na área específica do software e correspondente hardware das
ferramentas e centralinas automóveis. Os problemas decorrentes de tal
software serão identificados e, dessa identificação deverá ficar claro, que
praticamente todos esses problemas têm origem directa ou indirecta no facto
de se continuar a fazer um uso exaustivo de "tool chains" extremamente
compridas e complexas. De forma semelhante, no hardware, os problemas
têm origem na extrema complexidade e inter-dependência das arquitecturas
dos processadores. As consequências distribuem-se por uma extensa lista de
"pitfalls" que também serão exaustivamente enumeradas, identificadas e
caracterizadas.
São ainda propostas soluções para os diversos problemas actuais e
correspondentes implementações dessas mesmas soluções. Todo este
trabalho final faz parte de um sistema "proof-of-concept" designado
"ECU2010". O elemento central deste sistema é o já referido conceito de
“Macro”, que consiste num bloco gráfico que representa uma de muitas
operações necessárias num sistema automóvel, como sejam funções
aritméticas, lógicas, de filtragem, de integração, de multiplexagem, entre
outras. O resultado final do trabalho proposto assenta numa única ferramenta,
totalmente integrada que permite o desenvolvimento e gestão de todo o
sistema de forma simples numa única interface visual. Parte do resultado
apresentado assenta numa plataforma hardware totalmente adaptada ao
software, bem como na elevada flexibilidade e escalabilidade, para além de
permitir a utilização de exactamente a mesma tecnologia quer para a
centralina, como para o datalogger e para os periféricos.
Os sistemas actuais assentam num percurso maioritariamente evolutivo,
apenas permitindo a calibração online de parâmetros, mas nunca a alteração
online dos próprios algoritmos das funcionalidades automóveis. Pelo contrário,
o sistema desenvolvido e descrito nesta tese apresenta a vantagem de seguir
um "clean-slate approach", pelo que tudo pode ser globalmente repensado. No
final e para além de todas as restantes características, o
“LIVE-PROTOTYPING” é a funcionalidade mais relevante, ao permitir alterar
algoritmos automóveis (ex: injecção, ignição, controlo lambda, etc.) de forma
100% online, mantendo o motor constantemente a trabalhar e sem nunca ter
de o parar ou re-arrancar para efectuar tais alterações. Isto elimina
consequentemente qualquer "turnaround delay" tipicamente presente em
qualquer sistema automóvel actual, aumentando de forma significativa a
eficiência global do sistema e da sua utilização
Commissioning perspectives for the ATLAS Pixel Detector
The ATLAS Pixel Detector, the innermost sub-detector of the ATLAS experiment at
the Large Hadron Collider, CERN, is an 80 million channel silicon pixel tracking
detector designed for high-precision charged particle tracking and secondary vertex
reconstruction. It was installed in the ATLAS experiment and commissioning for the
first proton-proton collision data taking in 2008 has begun. Due to the complex layout
and limited accessibility, quality assurance measurements were continuously
performed during production and assembly to ensure that no problematic components
are integrated. The assembly of the detector at CERN and related quality assurance
measurement results, including comparison to previous production measurements,
will be presented. In order to verify that the integrated detector, its data acquisition
readout chain, the ancillary services and cooling system as well as the detector control
and data acquisition software perform together as expected approximately 8% of the
detector system was progressively assembled as close to the final layout as possible.
The so-called System Test laboratory setup was operated for several months under
experiment-like environment conditions. The interplay between different detector
components was studied with a focus on the performance and tunability of the optical
data transmission system. Operation and optical tuning procedures were developed
and qualified for the upcoming commissioning. The front-end electronics preamplifier
threshold tuning and noise performance were studied and noise occupancy of the
detector with low sensor bias voltages was investigated. Data taking with cosmic
muons was performed to test the data acquisition and trigger system as well as the
offline reconstruction and analysis software. The data quality was verified with an
extended version of the pixel online monitoring package which was implemented for
the ATLAS Combined Testbeam. The detector raw data of the Combined Testbeam
and of the System Test cosmic run was converted for offline data analysis with the
Pixel bytestream converter which was continuously extended and adapted according
to the offline analysis software needs