A Massively Parallel Algorithm for the Approximate Calculation of Inverse p-th Roots of Large Sparse Matrices

We present the submatrix method, a highly parallelizable method for the approximate calculation of inverse p-th roots of large sparse symmetric matrices which are required in different scientific applications. We follow the idea of Approximate Computing, allowing imprecision in the final result in order to be able to utilize the sparsity of the input matrix and to allow massively parallel execution. For an n x n matrix, the proposed algorithm allows to distribute the calculations over n nodes with only little communication overhead. The approximate result matrix exhibits the same sparsity pattern as the input matrix, allowing for efficient reuse of allocated data structures. We evaluate the algorithm with respect to the error that it introduces into calculated results, as well as its performance and scalability. We demonstrate that the error is relatively limited for well-conditioned matrices and that results are still valuable for error-resilient applications like preconditioning even for ill-conditioned matrices. We discuss the execution time and scaling of the algorithm on a theoretical level and present a distributed implementation of the algorithm using MPI and OpenMP. We demonstrate the scalability of this implementation by running it on a high-performance compute cluster comprised of 1024 CPU cores, showing a speedup of 665x compared to single-threaded execution

On the Feasibility and Limitations of Just-in-Time Instruction Set Extension for FPGA-Based Reconfigurable Processors

Reconfigurable instruction set processors provide the possibility of tailor the instruction set of a CPU to a particular application. While this customization process could be performed during runtime in order to adapt the CPU to the currently executed workload, this use case has been hardly investigated. In this paper, we study the feasibility of moving the customization process to runtime and evaluate the relation of the expected speedups and the associated overheads. To this end, we present a tool flow that is tailored to the requirements of this just-in-time ASIP specialization scenario. We evaluate our methods by targeting our previously introduced Woolcano reconfigurable ASIP architecture for a set of applications from the SPEC2006, SPEC2000, MiBench, and SciMark2 benchmark suites. Our results show that just-in-time ASIP specialization is promising for embedded computing applications, where average speedups of 5x can be achieved by spending 50 minutes for custom instruction identification and hardware generation. These overheads will be compensated if the applications execute for more than 2 hours. For the scientific computing benchmarks, the achievable speedup is only 1.2x, which requires significant execution times in the order of days to amortize the overheads

Application and development of zero-valent iron (ZVI) for groundwater and wastewater treatment

Zero-valent iron has been used for more than 130 years for water treatment. It is based on redox reactions as well as on sorption to the corrosion products of iron. It is successfully applied for the removal of metals and organic pollutants from groundwater and wastewater. There are different variations how zero-valent iron can be used, especially (i) permeable reactive barriers, (ii) fluidized bed reactors and (iii) nanoscale zero-valent iron. Permeable reactive barriers are used for in situ treatment of groundwater in trench-like constructions or in a funnel and gate system. Their advantages are low maintenance cost, inexpensive construction and prevention of excavation wastes, and their disadvantages are surface passivation and clogging of pores by corrosion products. Zero-valent iron nanoparticles are injected directly in contaminated soil or groundwater. Their advantages are a higher reactivity than coarse-grained zero-valent iron and their mobility in the subsurface to reach the contaminated areas. However, they also have some major disadvantages like fast ageing in the system, phytotoxicity, agglomeration during migration and high costs. The latest development is a fluidized bed process (“ferrodecont process”) which avoids the passivation and clogging observed in permeable reactive barriers as well as the high costs and toxicity issues of nanoscale zero-valent iron. First results of this technology for Cr(VI) and organically contaminated groundwaters and metal removal from industrial wastewaters are highly promising

First Nations in Kanada

Kampf der First Nations in Kanada um das Recht auf postsekundäre Bildung als eine aus den Treaties resultierende Vertragsverpflichtung Kanadas, sowie Beleuchtung der Zwangsassimilierung in den Residential Schools.The Struggle of First Nations in Canada for Post-Secondary Education as a Treaty Right, after the sad history of forced assimilation in Indian Residential Schools

FPGA Acceleration of Communication-Bound Streaming Applications: Architecture Modeling and a 3D Image Compositing Case Study

Reconfigurable computers usually provide a limited number of different memory resources, such as host memory, external memory, and on-chip memory with different capacities and communication characteristics. A key challenge for achieving high-performance with reconfigurable accelerators is the efficient utilization of the available memory resources. A detailed knowledge of the memories' parameters is key for generating an optimized communication layout. In this paper, we discuss a benchmarking environment for generating such a characterization. The environment is built on IMORC, our architectural template and on-chip network for creating reconfigurable accelerators. We provide a characterization of the memory resources available on the XtremeData XD1000 reconfigurable computer. Based on this data, we present as a case study the implementation of a 3D image compositing accelerator that is able to double the frame rate of a parallel renderer

Erneuerbare Energieproduktion: Vorhandenes Wissen und dessen Generierung in der Bevölkerung

Nachhaltige Entwicklung entspricht keinem konkreten Bündel von Vorgaben und Regeln, sondern stellt ein dynamisches System aus sozialen, wirtschaftlichen und umweltbezogenen Faktoren dar. Dieser Feststellung folgend findet sich in zahlreichen Studien, welche sich mit erneuerbarer, nachhaltiger Energieproduktion beschäftigen die Feststellung, dass Technologie kein Garant für den Erfolg eines solchen Vorhabens ist. Daher wurde in dieser Forschungsarbeit der Versuch unternommen, die Rolle des Informationsgrades der Bevölkerung zu erneuerbarer Energieproduktion und den Einfluss auf die Entwicklung einer nachhaltigen Energieproduktion zu untersuchen. Es zeigt sich, dass Wissen von essentieller Bedeutung für die Zustimmung, Unterstützung und selbst den Besitz erneuerbarer Energieanlagen ist. Zudem finden sich Zusammenhänge zwischen der Anzahl an genützten Informationsquellen, der Ausbildung, Schule und möglicherweise traditionellen Geschlechterrollen. Soziale Aspekte sind daher von erheblichem Interesse für die Entwicklung eines nachhaltigen Energiesektors. Diesen Erkenntnissen folgend sind die bedingenden Faktoren des Wissens über erneuerbarer Energieproduktion von immensem Interesse und bedürfen weiterer Erforschung.Sustainable development cannot be defined by specific rules or instructions but displays characteristics of a dynamic system, a dynamic system based on social, economic and environmental aspects. Various studies have shown that a sustainable energy sector is not a consequence of using renewable energy technologies, but those technologies are a key factor in the development of such. Based on this conclusion, this scientific paper tried to find answers on how the specific knowledge for renewable energy relates to the evolution of sustainable energy production. Knowledge is essential for the approval, support and even the ownership of renewable energy systems. Furthermore connections between used information inputs, education and possible traditional sexual stereotypes were found. Based on these findings it seems that various social aspects influence the development of a sustainable energy sector. The specific knowledge of renewable energy production is essential for the development of a sustainable energy sector. Therefor it seems of great interest and demands further research