FLECSim-SoC: A Flexible End-to-End Co-Design Simulation Framework for System on Chips

Hardware accelerators for deep neural networks (DNNs) have established themselves over the past decade. Most developments have worked towards higher efficiency with an individual application in mind. This highlights the strong relationship between co-designing the accelerator together with the requirements of the application. Currently for a structured design flow, however, it lacks a tool to evaluate a DNN accelerator embedded in a System on Chip (SoC) platform.To address this gap in the state of the art, we introduce FLECSim, a tool framework that enables an end-to-end simulation of an SoC with dedicated accelerators, CPUs and memories. FLECSim offers flexible configuration of the system and straightforward integration of new accelerator models in both SystemC and RTL, which allows for early design verification. During the simulation, FLECSim provides metrics of the SoC, which can be used to explore the design space. Finally, we present the capabilities of FLECSim, perform an exemplary evaluation with a systolic array-based accelerator and explore the design parameters in terms of accelerator size, power and performance

Data Movement Reduction for DNN Accelerators: Enabling Dynamic Quantization Through an eFPGA

Computational requirements for deep neural networks (DNNs) have been on a rising trend for years. Moreover, network dataflows and topologies are becoming more sophisticated to address more challenging applications. DNN accelerators cannot adopt quickly to the constantly changing DNNs. In this paper, we describe our approach to make a static accelerator more versatile by adding an embedded FPGA (eFPGA). The eFPGA is tightly coupled to the on-chip network, which allows us to pass data through the eFPGA before and after it is processed by the DNN accelerator. Hence, the proposed solution is able to quickly address changing requirements. To show the benefits of this approach, we propose an eFPGA application that enables dynamic quantization of data. We can fit four number converters on an $1.5mm^2$ eFPGA, which can process 400M data elements per second. We will practically validate our work in the near future, with a SoC tapeout in the ongoing EPI project

Synthesestrategien für die Darstellung linearer Koordinationspolymere und kernresonanzspektroskopische Untersuchungen an Syntheselösungen von Zr-MOFs

Die in drei Dimensionen verknüpften und porösen Metall-Organischen Gerüstverbindungen (metal-organic frameworks: MOFs) bieten interessante Ansatzpunkte für verschiedene Anwendungen, wie Sensorik oder Separation. Ihre in nur einer Dimension verknüpften Gegenstücke, die linearen Koordinationspolymere (linear coordination polymers: LCPs), können als vereinfachte Modellsysteme für MOFs betrachtet werden. In einer explorativ ausgerichteten Untersuchung zu LCPs wurde die Grundlage für ein Modellsystem aufgebaut, welches für die Synthese von LCPs mit einer definierten Abfolge unterschiedlicher Bausteine genutzt werden kann. Wie in ähnlichen biologischen Systemen, wie z.B. DNA/RNA bietet das die Möglichkeit, Informationen zu codieren. Der zweite Schwerpunkt der Arbeit lag auf der Untersuchung von Synthesen von Zr-MOFs in Dimethylformamid (DMF) mittels Kernresonanzspektroskopie, um mögliche Nebenreaktionen aufzuklären. Als Basis für die Synthese neuer LCPs dienten Silber(I)-Kationen und N Donor Linkermoleküle sowie 18 Krone 6 als zusätzlicher Ligand, welcher das Silberatom gegen störende Einflüsse aus der Reaktionslösung abschirmt. Es konnten verschiedene neue LCPs synthetisiert werden, deren struktureller Aufbau mithilfe von Einkristalldiffraktometrie aufgeklärt wurde. Neben der Synthese dieser LCPs wurden Versuche durchgeführt, um die Eignung anderer Metallatome für eine mögliche Erweiterung des Reaktionssystems zu überprüfen. Dafür wurden Molekülkomplexe synthetisiert, bei denen die bidentaten Linkermoleküle durch entsprechende monodentate Liganden ersetzt wurden. Hier wurden Verbindungen mit Eisen(II), Mangan(II), Kupfer(II) und Quecksilber(II) erhalten und ihre Kristallstrukturen röntgenographisch aufgeklärt. Eine Bestimmung der Bindungsvalenzen anhand der Atomabstände in der Koordinationssphäre des jeweiligen Zentralatoms wurde genutzt, um die gefundenen Koordinationsumgebungen im Hinblick auf ihre Eignung für ein solches Modellsystem zu beurteilen. Für die Untersuchung von Nebenreaktionen bei Zr-MOF-Synthesen wurden miniaturisierte Reaktionsansätze mit verschiedenen Linkermolekülen und organischen Reaktionszusätzen (Modulatoren) durchgeführt. In kernresonanzspektroskopischen Untersuchungen konnte die Isotopenanreicherung genutzt werden, um verschiedene Reaktionsprodukte eindeutig zu identifizieren und den jeweiligen Grad der Umsetzung zu quantifizieren. Konkret konnten verschiedene Reaktionen mit Dimethylamin, einem Zersetzungsprodukt des Lösungsmittels, gefunden werden. Mit den als Modulatoren, beziehungsweise als Linker verwendeten Carbonsäuren bildet Dimethylamin Amide, welche eindeutig nachgewiesen werden konnten. Für die Monocarbonsäuren Ameisensäure, Essigsäure und Benzoesäure und die Dicarbonsäuren Terephthalsäure und Fumarsäure wurde zudem der zeitliche Verlauf ihrer Umsetzung zum Amid bestimmt.Because of their modular composition coordination polymers form a group of compounds that is vast in numbers and versatile in their properties. On the one hand, the three-dimensionally connected metal organic frameworks (MOFs) offer interesting potential applications, like sensing or separation. On the other hand, the one-dimensionally connected linear coordination polymers (LCPs) can be regarded as simplified model systems for MOFs. In an explorative investigation into LCPs with a strong connection between the metal atom and linker molecule, it was the goal to set up a model system that allows the formation of LCPs with a defined sequence of different building blocks. Similar to biological systems like DNA/RNA, this can be used to encode information. The second focus of the thesis lay on nuclear magnetic resonance investigations on Zr MOF syntheses in the solvent dimethylformamide (DMF), which were carried out in order to identify possible side reactions. The synthesis of new LCPs was based on silver(I) cations and N donor linker molecules, as well as on 18 crown 6 as an additional ligand to protect the silver atom against interfering influences from the reaction solution. The structures of newly-found compounds were determined via single-crystal X-ray diffraction. Besides the experiments carried out to form these LCPs, experiments with iron(II), manganese(II), copper(II) and mercury(II) cations were conducted to find other fitting combinations of metal cations and linker molecules. For this, molecular complexes were synthesized in which the bidentate linker molecules were changed to monodentate ligands. The bond-lengths to the neighboring atoms of the central atoms of these complexes were used to calculate the respective bond valences. These valences served as a basis to evaluate the suitability of the coordination spheres found in these complexes to form LCPs relevant for this model system. The investigation of side reactions in DMF-based Zr-MOF syntheses was performed in miniaturized reaction vessels using different linker molecules and organic additives (modulators). Isotopically enriched compounds were utilized to trace back and identify reaction products and to determine the corresponding degree to which they had formed. Specifically, reactions with dimethylamine – a decomposition product of DMF – could be detected. Among these are dimethyl amides which are formed with modulating monocarboxylic acids as well as with dicarboxylic acids, which serve as linker molecules. For the monocarboxylic acids formic acid, acetic acid, and benzoic acid and for the dicarboxylic acids fumaric acid and terephthalic acid, also the time dependences of the amide formation were determined

Einsatz von kollaborativen virtuellen Umgebungen bei der berufsbegleitenden Weiterbildung

Berufsbegleitende Aus- und Weiterbildung gewinnt vor dem nachhaltigen Trend von der Produktions- zur Wissensarbeit, der demographischen Entwicklung, der immer kürzer werdenden Halbwertzeit des Wissens und neuen Modellen in der Ausbildung wie die Umstellung auf Bachelor- und Masterstudiengänge zunehmend an Bedeutung. Insbesondere die Universitäten öffnen ihr Angebot für die Aus- und Weiterbildung von Berufstätigen. Um hier die geforderte Flexibilität beim Lernen, wie z.B. Orts- und Zeitunabhängigkeit zu ermöglichen, ist der Einsatz von E-Learning Systemen notwendig. Anhand des Online-Weiterbildungsstudiengangs Logistikmanagement wird der kombinierte Einsatz von Learning Management Systemen (LMS) und virtuellem Klassenzimmer gezeigt.Schlüsselwörter: E-Learning, virtueller Klassenraum, kollaborative Lernumgebungen, berufsbegleitende Weiterbildung, Learning Management Syste

Einsatz von kollaborativen virtuellen Umgebungen bei der berufsbegleitenden Weiterbildung

Berufsbegleitende Aus- und Weiterbildung gewinnt vor dem nachhaltigen Trend von der Produktions- zur Wissensarbeit, der demographischen Entwicklung, der immer kürzer werdenden Halbwertzeit des Wissens und neuen Modellen in der Ausbildung wie die Umstellung auf Bachelor- und Masterstudiengänge zunehmend an Bedeutung. Insbesondere die Universitäten öffnen ihr Angebot für die Aus- und Weiterbildung von Berufstätigen. Um hier die geforderte Flexibilität beim Lernen, wie z.B. Orts- und Zeitunabhängigkeit zu ermöglichen, ist der Einsatz von E-Learning Systemen notwendig. Anhand des Online-Weiterbildungsstudiengangs Logistikmanagement wird der kombinierte Einsatz von Learning Management Systemen (LMS) und virtuellem Klassenzimmer gezeigt.Schlüsselwörter: E-Learning, virtueller Klassenraum, kollaborative Lernumgebungen, berufsbegleitende Weiterbildung, Learning Management Syste

Additive manufacturing of metal-bonded grinding tools

Grinding tools with superabrasive grains can be manufactured from different bond materials. In several industrial applications, metallic bond systems are used. In general, these show good grain retention and offer a high thermal conductivity, when compared to the other widely used bond types such as vitrified and resin bonds. One drawback of the metallic bond is the lack of pores in the grinding layer. This is caused by the manufacturing processes that are typically used, like brazing or hot pressing. These generally produce very dense layers. The high density and low porosity lead to comparatively little space for the transport of lubricant, coolant, and chips. One approach to eliminate this disadvantage is to introduce cavities into the grinding layer, using the laser powder bed fusion technique (LPBF). In order to evaluate the general suitability of LPBF in combination with the bond material and diamond grains, grinding layer samples with a nickel-titanium bond were produced. The abrasive behavior of these samples was tested in scratch tests on cemented carbide to verify the applicability as grinding tools. While the diamond grains in the powder mixture are not part of the fusion process, they also did not interfere with the manufacturing process, and the scratch tests showed promising abrasive capabilities. The grinding layer itself withstood the process forces, and no grain breakout could be observed. This indicates that the grain retention forces are high enough for the grinding process and that NiTi has a high potential as a bonding material for the manufacturing of grinding tools via LPBF

Insight into the mechanism of modulated syntheses: in situ synchrotron diffraction studies on the formation of Zr-fumarate MOF

In this work, the formation of a Zr-based metal-organic framework (MOF), Zr-fumarate MOF (Zr-fum MOF), is studied in situ by energy-dispersive diffraction. The Zr-fum MOF can be synthesised in DMF as well as in water-based synthesis systems. In both cases, its formation requires modulation, i.e. a monocarboxylic acid which is used as the modulator has to be added to the synthesis mixture. In general, different mechanisms of modulation are possible, for example, deprotonation of the linker molecule (deprotonation modulation) or coordination modulation (wherein the molecules of the modulator compete with the linker molecules for the coordination sites at the inorganic building units). Independently of the specific mechanism, modulation often improves the reproducibility of the MOF synthesis and the crystallinity of the product and may be used to control crystal size and morphology. This study is the first to investigate the kinetics of modulated MOF syntheses with regard to coordination modulation. According to this concept, the addition of a modulator usually decelerates the reaction. Our kinetic investigations show that this is the case for the formation of Zr-fum MOF in the water-based synthesis with formic acid used as a modulator. On the contrary, the addition of formic acid to the DMF-based synthesis results in an accelerating effect. This unexpected effect can be attributed to a small amount of water present in formic acid. Correspondingly, the addition of water to the synthesis mixture also showed an accelerating effect. These investigations emphasise the subtle interplay of the different ingredients in a MOF synthesis. In the case of the Zr-fum MOF, both the modulator formic acid and the water content strongly affect the kinetics of crystallisation. Quantitative evaluation of the kinetic data using the Gualtieri equation provides additional insight into the mechanisms of coordination-modulated MOF formation reactions and excludes the idea of deprotonation modulation.DFG/Porous Metal–Organic Frameworks/1362DESY/I-2011055

Towards reconfigurable accelerators in HPC: Designing a multipurpose eFPGA tile for heterogeneous SoCs

The goal of modern high performance computing platforms is to combine low power consumption and high throughput. Within the European Processor Initiative (EPI), such an SoC platform to meet the novel exascale requirements is built and investigated. As part of this project, we introduce an embedded Field Programmable Gate Array (eFPGA), adding flexibility to accelerate various workloads. In this article, we show our approach to design the eFPGA tile that supports the EPI SoC. While eFPGAs are inherently reconfigurable, their initial design has to be determined for tape-out. The design space of the eFPGA is explored and evaluated with different configurations of two HPC workloads, covering control and dataflow heavy applications. As a result, we present a well-balanced eFPGA design that can host several use cases and potential future ones by allocating 1% of the total EPI SoC area. Finally, our simulation results of the architectures on the eFPGA show great performance improvements over their software counterparts.European Processor Initiative (EPI) project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 826647, from Spanish Government (PID2019- 107255GB-C21/AEI /10.13039/501100011033), and from Generalitat de Catalunya (contracts 2017-SGR-1414 and 2017-SGR-1328). M. Moreto is partially supported by the Spanish Ministry of Economy, Industry and Competitiveness under Ramon y Cajal fellowship No. RYC-2016-21104.Peer ReviewedPostprint (author's final draft

Emergent Trion-Phonon Coupling in Atomically-Reconstructed MoSe2_2-WSe2_2 Heterobilayers

In low-temperature resonant Raman experiments on MoSe$_2$-WSe$_2$ heterobilayers, we identify a hybrid interlayer shear mode (HSM) with an energy, close to the interlayer shear mode (SM) of the heterobilayers, but with a much broader, asymmetric lineshape. The HSM shows a pronounced resonance with the intralayer hybrid trions (HX$^-$) of the MoSe$_2$ and WSe$_2$ layers, only. No resonance with the neutral intralayer excitons is found. First-principles calculations reveal a strong coupling of Q-valley states, which are delocalized over both layers and participate in the HX$^-$, with the SM. This emerging trion-phonon coupling may be relevant for experiments on gate-controlled heterobilayers.Comment: 6 pages, 3 figure