177 research outputs found

    National Scale Assesments For Austria And Denmark

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    From curating to Cedong: Long March: A walking visual display and the emergence of contemporary Chinese curating

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    Long March: A Walking Visual Display (abbreviated as Long March) was an internationally renowned large-scale curatorial project curated by Lu Jie and executive curator Qiu Zhijie in China in 2002. It involved over 150 artists in an intense journey of temporary exhibitions and events along the historical and revolutionary Long March route in China. Based on four years of archival research and nearly thirty interviews with key participants, especially with Lu Jie, this thesis, as the first significant research on Long March, restores the international trajectory of the project in the wake of globalisation in the Chinese art ecology. The thesis details how the project grew out of Chinese artists’ and critics’ concern over the dependence of contemporary Chinese art on Western art and its art system in the 1990s. Influenced by the surging experimental curating practices in the West and in China, the two curators creatively appropriated work models of Socialist China — revolution propaganda and mass mobilisation — in their curatorial practice. In so doing, they attempted to open up alternative spaces and invent new approaches to art in a Chinese context. This thesis argues Long March reinvented Western curating for the Chinese context. Having greatly expanded the discourse and practice of curating, Long March became a watershed moment in the emergence of independent curators and curating in mainland China. To shed light on the transcultural factors shaping the project, this thesis embodies a chronological order in three sections: 1) Lu’s early trajectory in mainland China, Hong Kong and abroad as a young artist, editor, and art dealer (1964–1998); 2) the birth of the project’s curatorial proposal at Goldsmiths, London, and its development in New York (1998–2001); 3) the project’s mobilisation and realisation in China (2002). Sourcing from first-hand documentation, internet archives, video footage and interviews, the research restores the complex dynamic of the project’s realisation, especially its unprecedented open nature of organising, improvisational display of artworks by curators as agents of artists, and clashes caused by different understandings of exhibition-making. The gap between the original curatorial concept and the on-site execution led to the project’s halt halfway, demonstrating the tension in curating between an individual’s creative approach and the realities of the murky and muddy process of collaboration. Re-examining Long March in relation to contemporary Chinese art, this thesis considers how the project has opened new spaces and reactivated overlooked local approaches for contemporary art in China. Curating as an unsolidified discipline also made it possible for Long March and Lu Jie to demonstrate a heterogeneous mode of artmaking and understanding of art. This thesis argues that the approaches and intentions found in Long March differed fundamentally from typical approaches to curating and participatory art practices of the West, with its aim to mobilise participants and instigate practitioners for self-reflection instead of displaying artworks as objects. I conclude by arguing that the work of Long March and similar curatorial projects in China should be understood as cedong, which initially means to devise plans, mobilise the public and instigate people for political movements. Free from the burden of art history and the long tradition of museums, Cedong can liberate curating and inspire more self-instigated actions reacting to urgency

    Database System Acceleration on FPGAs

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    Relational database systems provide various services and applications with an efficient means for storing, processing, and retrieving their data. The performance of these systems has a direct impact on the quality of service of the applications that rely on them. Therefore, it is crucial that database systems are able to adapt and grow in tandem with the demands of these applications, ensuring that their performance scales accordingly. In the past, Moore's law and algorithmic advancements have been sufficient to meet these demands. However, with the slowdown of Moore's law, researchers have begun exploring alternative methods, such as application-specific technologies, to satisfy the more challenging performance requirements. One such technology is field-programmable gate arrays (FPGAs), which provide ideal platforms for developing and running custom architectures for accelerating database systems. The goal of this thesis is to develop a domain-specific architecture that can enhance the performance of in-memory database systems when executing analytical queries. Our research is guided by a combination of academic and industrial requirements that seek to strike a balance between generality and performance. The former ensures that our platform can be used to process a diverse range of workloads, while the latter makes it an attractive solution for high-performance use cases. Throughout this thesis, we present the development of a system-on-chip for database system acceleration that meets our requirements. The resulting architecture, called CbMSMK, is capable of processing the projection, sort, aggregation, and equi-join database operators and can also run some complex TPC-H queries. CbMSMK employs a shared sort-merge pipeline for executing all these operators, which results in an efficient use of FPGA resources. This approach enables the instantiation of multiple acceleration cores on the FPGA, allowing it to serve multiple clients simultaneously. CbMSMK can process both arbitrarily deep and wide tables efficiently. The former is achieved through the use of the sort-merge algorithm which utilizes the FPGA RAM for buffering intermediate sort results. The latter is achieved through the use of KeRRaS, a novel variant of the forward radix sort algorithm introduced in this thesis. KeRRaS allows CbMSMK to process a table a few columns at a time, incrementally generating the final result through multiple iterations. Given that acceleration is a key objective of our work, CbMSMK benefits from many performance optimizations. For instance, multi-way merging is employed to reduce the number of merge passes required for the execution of the sort-merge algorithm, thus improving the performance of all our pipeline-breaking operators. Another example is our in-depth analysis of early aggregation, which led to the development of a novel cache-based algorithm that significantly enhances aggregation performance. Our experiments demonstrate that CbMSMK performs on average 5 times faster than the state-of-the-art CPU-based database management system MonetDB.:I Database Systems & FPGAs 1 INTRODUCTION 1.1 Databases & the Importance of Performance 1.2 Accelerators & FPGAs 1.3 Requirements 1.4 Outline & Summary of Contributions 2 BACKGROUND ON DATABASE SYSTEMS 2.1 Databases 2.1.1 Storage Model 2.1.2 Storage Medium 2.2 Database Operators 2.2.1 Projection 2.2.2 Filter 2.2.3 Sort 2.2.4 Aggregation 2.2.5 Join 2.2.6 Operator Classification 2.3 Database Queries 2.4 Impact of Acceleration 3 BACKGROUND ON FPGAS 3.1 FPGA 3.1.1 Logic Element 3.1.2 Block RAM (BRAM) 3.1.3 Digital Signal Processor (DSP) 3.1.4 IO Element 3.1.5 Programmable Interconnect 3.2 FPGADesignFlow 3.2.1 Specifications 3.2.2 RTL Description 3.2.3 Verification 3.2.4 Synthesis, Mapping, Placement, and Routing 3.2.5 TimingAnalysis 3.2.6 Bitstream Generation and FPGA Programming 3.3 Implementation Quality Metrics 3.4 FPGA Cards 3.5 Benefits of Using FPGAs 3.6 Challenges of Using FPGAs 4 RELATED WORK 4.1 Summary of Related Work 4.2 Platform Type 4.2.1 Accelerator Card 4.2.2 Coprocessor 4.2.3 Smart Storage 4.2.4 Network Processor 4.3 Implementation 4.3.1 Loop-based implementation 4.3.2 Sort-based Implementation 4.3.3 Hash-based Implementation 4.3.4 Mixed Implementation 4.4 A Note on Quantitative Performance Comparisons II Cache-Based Morphing Sort-Merge with KeRRaS (CbMSMK) 5 OBJECTIVES AND ARCHITECTURE OVERVIEW 5.1 From Requirements to Objectives 5.2 Architecture Overview 5.3 Outlineof Part II 6 COMPARATIVE ANALYSIS OF OPENCL AND RTL FOR SORT-MERGE PRIMITIVES ON FPGAS 6.1 Programming FPGAs 6.2 RelatedWork 6.3 Architecture 6.3.1 Global Architecture 6.3.2 Sorter Architecture 6.3.3 Merger Architecture 6.3.4 Scalability and Resource Adaptability 6.4 Experiments 6.4.1 OpenCL Sort-Merge Implementation 6.4.2 RTLSorters 6.4.3 RTLMergers 6.4.4 Hybrid OpenCL-RTL Sort-Merge Implementation 6.5 Summary & Discussion 7 RESOURCE-EFFICIENT ACCELERATION OF PIPELINE-BREAKING DATABASE OPERATORS ON FPGAS 7.1 The Case for Resource Efficiency 7.2 Related Work 7.3 Architecture 7.3.1 Sorters 7.3.2 Sort-Network 7.3.3 X:Y Mergers 7.3.4 Merge-Network 7.3.5 Join Materialiser (JoinMat) 7.4 Experiments 7.4.1 Experimental Setup 7.4.2 Implementation Description & Tuning 7.4.3 Sort Benchmarks 7.4.4 Aggregation Benchmarks 7.4.5 Join Benchmarks 7. Summary 8 KERRAS: COLUMN-ORIENTED WIDE TABLE PROCESSING ON FPGAS 8.1 The Scope of Database System Accelerators 8.2 Related Work 8.3 Key-Reduce Radix Sort(KeRRaS) 8.3.1 Time Complexity 8.3.2 Space Complexity (Memory Utilization) 8.3.3 Discussion and Optimizations 8.4 Architecture 8.4.1 MSM 8.4.2 MSMK: Extending MSM with KeRRaS 8.4.3 Payload, Aggregation and Join Processing 8.4.4 Limitations 8.5 Experiments 8.5.1 Experimental Setup 8.5.2 Datasets 8.5.3 MSMK vs. MSM 8.5.4 Payload-Less Benchmarks 8.5.5 Payload-Based Benchmarks 8.5.6 Flexibility 8.6 Summary 9 A STUDY OF EARLY AGGREGATION IN DATABASE QUERY PROCESSING ON FPGAS 9.1 Early Aggregation 9.2 Background & Related Work 9.2.1 Sort-Based Early Aggregation 9.2.2 Cache-Based Early Aggregation 9.3 Simulations 9.3.1 Datasets 9.3.2 Metrics 9.3.3 Sort-Based Versus Cache-Based Early Aggregation 9.3.4 Comparison of Set-Associative Caches 9.3.5 Comparison of Cache Structures 9.3.6 Comparison of Replacement Policies 9.3.7 Cache Selection Methodology 9.4 Cache System Architecture 9.4.1 Window Aggregator 9.4.2 Compressor & Hasher 9.4.3 Collision Detector 9.4.4 Collision Resolver 9.4.5 Cache 9.5 Experiments 9.5.1 Experimental Setup 9.5.2 Resource Utilization and Parameter Tuning 9.5.3 Datasets 9.5.4 Benchmarks on Synthetic Data 9.5.5 Benchmarks on Real Data 9.6 Summary 10 THE FULL PICTURE 10.1 System Architecture 10.2 Benchmarks 10.3 Meeting the Objectives III Conclusion 11 SUMMARY AND OUTLOOK ON FUTURE RESEARCH 11.1 Summary 11.2 Future Work BIBLIOGRAPHY LIST OF FIGURES LIST OF TABLE

    Overcoming Memory Weakness with Unified Fairness

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    We consider the verification of liveness properties for concurrent programs running on weak memory models. To that end, we identify notions of fairness that preclude demonic non-determinism, are motivated by practical observations, and are amenable to algorithmic techniques. We provide both logical and stochastic definitions of our fairness notions and prove that they are equivalent in the context of liveness verification. In particular, we show that our fairness allows us to reduce the liveness problem (repeated control state reachability) to the problem of simple control state reachability. We show that this is a general phenomenon by developing a uniform framework which serves as the formal foundation of our fairness definition and can be instantiated to a wide landscape of memory models. These models include SC, TSO, PSO, (Strong/Weak) Release-Acquire, Strong Coherence, FIFO-consistency, and RMO.Comment: 32 pages. To appear in Proc. 35th International Conference on Computer Aided Verification (CAV) 202

    EVOLUTION OF THE SUBCONTINENTAL LITHOSPHERE DURING MESOZOIC TETHYAN RIFTING: CONSTRAINTS FROM THE EXTERNAL LIGURIAN MANTLE SECTION (NORTHERN APENNINE, ITALY)

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    Our study is focussed on mantle bodies from the External Ligurian ophiolites, within the Monte Gavi and Monte Sant'Agostino areas. Here, two distinct pyroxenite-bearing mantle sections were recognized, mainly based on their plagioclase-facies evolution. The Monte Gavi mantle section is nearly undeformed and records reactive melt infiltration under plagioclase-facies conditions. This process involved both peridotites (clinopyroxene-poor lherzolites) and enclosed spinel pyroxenite layers, and occurred at 0.7–0.8 GPa. In the Monte Gavi peridotites and pyroxenites, the spinel-facies clinopyroxene was replaced by Ca-rich plagioclase and new orthopyroxene, typically associated with secondary clinopyroxene. The reactive melt migration caused increase of TiO2 contents in relict clinopyroxene and spinel, with the latter also recording a Cr2O3 increase. In the Monte Gavi peridotites and pyroxenites, geothermometers based on slowly diffusing elements (REE and Y) record high temperature conditions (1200-1250 °C) related to the melt infiltration event, followed by subsolidus cooling until ca. 900°C. The Monte Sant'Agostino mantle section is characterized by widespread ductile shearing with no evidence of melt infiltration. The deformation recorded by the Monte Sant'Agostino peridotites (clinopyroxene-rich lherzolites) occurred at 750–800 °C and 0.3–0.6 GPa, leading to protomylonitic to ultramylonitic textures with extreme grain size reduction (10–50 μm). Compared to the peridotites, the enclosed pyroxenite layers gave higher temperature-pressure estimates for the plagioclase-facies re-equilibration (870–930 °C and 0.8–0.9 GPa). We propose that the earlier plagioclase crystallization in the pyroxenites enhanced strain localization and formation of mylonite shear zones in the entire mantle section. We subdivide the subcontinental mantle section from the External Ligurian ophiolites into three distinct domains, developed in response to the rifting evolution that ultimately formed a Middle Jurassic ocean-continent transition: (1) a spinel tectonite domain, characterized by subsolidus static formation of plagioclase, i.e. the Suvero mantle section (Hidas et al., 2020), (2) a plagioclase mylonite domain experiencing melt-absent deformation and (3) a nearly undeformed domain that underwent reactive melt infiltration under plagioclase-facies conditions, exemplified by the the Monte Sant'Agostino and the Monte Gavi mantle sections, respectively. We relate mantle domains (1) and (2) to a rifting-driven uplift in the late Triassic accommodated by large-scale shear zones consisting of anhydrous plagioclase mylonites. Hidas K., Borghini G., Tommasi A., Zanetti A. & Rampone E. 2021. Interplay between melt infiltration and deformation in the deep lithospheric mantle (External Liguride ophiolite, North Italy). Lithos 380-381, 105855

    Enhancing solar energy generation potential in the villages of Rovaniemi, Lapland

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    Abstract. This master’s thesis investigated the solar energy potential of future plots in three different village groups in Lapland using existing provisional master plans. The investigation was conducted as part of the SINNI project. The project explores the potential of virtual power plants in the villages of Lapland. The target area of this research was three village groups in the Rovaniemi region around Sinetta, Vikajärvi and Vanttauskoski. The village groups were selected because the buildings form relatively cohesive groups from the point of view of energy generation, and the proximity of the areas to power lines and main roads. The project aims to characterize “SINNI villages”, which are to be defined by indicators such as their energy production potential, as well as geographical features such as location, land use patterns, and suitability of building stock. The expectation is that when defining the economic feasibility of solar power generation in SINNI villages, these criteria could be used as a basis to assess the techno-economic feasibility of similar sites in the future. The solar energy potential was first assessed considering future buildings on the best oriented building plots in the master plans. The hypothetical range of 120–180° from the true north was selected for the analysis as potentially feasible orientations for solar energy generation. The estimated solar energy potential for the future plots in the three village groups, considering this range of azimuths were 1.07GWh/year for Sinetta, 0.57GWh/year for Vikajärvi and 1.04GWh/year for Vanttauskoski. Secondly, the solar energy potential of all building plots in the 3 village groups were calculated to observe the difference in output. It was found that the solar energy potential of all future plots in the three Village Groups were 1.20GWh/year, 0.71GWh/year,1.47GWh/year respectively. The small differences observed were due to the fact that the majority of the future buildings in the master plans were adjusted well enough to support solar energy generation. Due to the Northern location of the villages, the issue of snow on the panels were also investigated, to ascertain missed solar energy generation potential attributed to snow covering the panels. The results show that 28.3% of the solar energy generation in Spring could be lost due to snow, if effective mitigation strategies are not implemented. The profitability of the solar investments was also analysed using Finsolar Profitability Calculator, from the perspective of homeowners. The results of this research indicate that deploying rooftop solar panels makes economic sense, if the roofs are in the 120–210° azimuth range, as this would provide a relatively fair payback period in the range of 19–23 years. Azimuths out of this range typically result in significantly higher payback period. The use of self-generated energy was also assessed and the consumption profiles for the village groups were analysed in juxtaposition with the self-produced energy under the framework of energy communities. The results show that solar power investments could be economically profitable even in Lapland, if the houses and roofs are sited optimally. The research also indicates that the energy community concept which have been brought into limelight in recent EU directives could potentially enhance the profitability of solar investments by facilitating energy sharing within the community which maximises the value of solar energy produced. They also potentially enhance customer participation, energy security, independence, efficiency, and sustainability which could be regarded as some of the most crucial goals in the energy sector for EU Member States

    Tools and Algorithms for the Construction and Analysis of Systems

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    This open access book constitutes the proceedings of the 28th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2022, which was held during April 2-7, 2022, in Munich, Germany, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022. The 46 full papers and 4 short papers presented in this volume were carefully reviewed and selected from 159 submissions. The proceedings also contain 16 tool papers of the affiliated competition SV-Comp and 1 paper consisting of the competition report. TACAS is a forum for researchers, developers, and users interested in rigorously based tools and algorithms for the construction and analysis of systems. The conference aims to bridge the gaps between different communities with this common interest and to support them in their quest to improve the utility, reliability, exibility, and efficiency of tools and algorithms for building computer-controlled systems

    LIPIcs, Volume 248, ISAAC 2022, Complete Volume

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    LIPIcs, Volume 248, ISAAC 2022, Complete Volum
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