Cache-Efficient Aggregation: Hashing Is Sorting

For decades researchers have studied the duality of hashing and sorting for the implementation of the relational operators, especially for efficient aggregation. Depending on the underlying hardware and software architecture, the specifically implemented algorithms, and the data sets used in the experiments, different authors came to different conclusions about which is the better approach. In this paper we argue that in terms of cache efficiency, the two paradigms are actually the same. We support our claim by showing that the complexity of hashing is the same as the complexity of sorting in the external memory model. Furthermore we make the similarity of the two approaches obvious by designing an algorithmic framework that allows to switch seamlessly between hashing and sorting during execution. The fact that we mix hashing and sorting routines in the same algorithmic framework allows us to leverage the advantages of both approaches and makes their similarity obvious. On a more practical note, we also show how to achieve very low constant factors by tuning both the hashing and the sorting routines to modern hardware. Since we observe a complementary dependency of the constant factors of the two routines to the locality of the input, we exploit our framework to switch to the faster routine where appropriate. The result is a novel relational aggregation algorithm that is cache-efficient---independently and without prior knowledge of input skew and output cardinality---, highly parallelizable on modern multi-core systems, and operating at a speed close to the memory bandwidth, thus outperforming the state-of-the-art by up to 3.7x

Artificial intelligence in the management of barrett’s esophagus and early esophageal adenocarcinoma

Esophageal adenocarcinoma is increasing in incidence and is the most common subtype of esophageal cancer in Western societies. The stepwise progression of Barrett´s metaplasia to high-grade dysplasia and invasive adenocarcinoma provides an opportunity for screening and surveillance. There are important unresolved issues, which include (i) refining the definition of the screening population in order to avoid unnecessary invasive diagnostics, (ii) a more precise prediction of the (very heterogeneous) individual progression risk from metaplasia to invasive cancer in order to better tailor surveillance recommendations, (iii) improvement of the quality of endoscopy in order to reduce the high miss rate for early neoplastic lesions, and (iv) support for the diagnosis of tumor infiltration depth in order to guide treatment decisions. Artificial intelligence (AI) systems might be useful as a support to better solve the above-mentioned issues

n-Type Doping of Vapor–Liquid–Solid Grown GaAs Nanowires

In this letter, n-type doping of GaAs nanowires grown by metal–organic vapor phase epitaxy in the vapor–liquid–solid growth mode on (111)B GaAs substrates is reported. A low growth temperature of 400°C is adjusted in order to exclude shell growth. The impact of doping precursors on the morphology of GaAs nanowires was investigated. Tetraethyl tin as doping precursor enables heavily n-type doped GaAs nanowires in a relatively small process window while no doping effect could be found for ditertiarybutylsilane. Electrical measurements carried out on single nanowires reveal an axially non-uniform doping profile. Within a number of wires from the same run, the donor concentrations ND of GaAs nanowires are found to vary from 7 × 1017 cm-3 to 2 × 1018 cm-3. The n-type conductivity is proven by the transfer characteristics of fabricated nanowire metal–insulator-semiconductor field-effect transistor devices

Synthesizing Adaptive Test Strategies from Temporal Logic Specifications

Constructing good test cases is difficult and time-consuming, especially if the system under test is still under development and its exact behavior is not yet fixed. We propose a new approach to compute test strategies for reactive systems from a given temporal logic specification using formal methods. The computed strategies are guaranteed to reveal certain simple faults in every realization of the specification and for every behavior of the uncontrollable part of the system's environment. The proposed approach supports different assumptions on occurrences of faults (ranging from a single transient fault to a persistent fault) and by default aims at unveiling the weakest one. Based on well-established hypotheses from fault-based testing, we argue that such tests are also sensitive for more complex bugs. Since the specification may not define the system behavior completely, we use reactive synthesis algorithms with partial information. The computed strategies are adaptive test strategies that react to behavior at runtime. We work out the underlying theory of adaptive test strategy synthesis and present experiments for a safety-critical component of a real-world satellite system. We demonstrate that our approach can be applied to industrial specifications and that the synthesized test strategies are capable of detecting bugs that are hard to detect with random testing

Анализ и выбор оптимальной технологии проведения работ по реконструкции компрессорного цеха линейно-производственного управления магистральных газопроводов

На основе нормативно-технической документации выбрана оптимальная технология проведения ремонтных работ на компрессорном цехе. Разработаны рекомендации по проведению ремонтных работ по реконструкции компрессорного цеха. Рассчитаны показатели энергоэффективности и коэффициенты технического состояния газоперекачивающих агрегатов до и после реконструкции компрессорного цеха.On the basic of technical documentation the optimal technology of repair at the compressor department was chosen. Recommendations for the repair work on the reconstruction of the compressor department. The energy efficiency indicators and the technical state coefficients of gas compressor units before and after the reconstruction of the compressor department are calculated

X-ray dark-field signal reduction due to hardening of the visibility spectrum

X-ray dark-field imaging enables a spatially-resolved visualization of small-angle X-ray scattering. Using phantom measurements, we demonstrate that a material's effective dark-field signal may be reduced by modification of the visibility spectrum by other dark-field-active objects in the beam. This is the dark-field equivalent of conventional beam-hardening, and is distinct from related, known effects, where the dark-field signal is modified by attenuation or phase shifts. We present a theoretical model for this group of effects and verify it by comparison to the measurements. These findings have significant implications for the interpretation of dark-field signal strength in polychromatic measurements.Comment: 11 pages, 6 figures. Previously submitted to IEEE Transactions on Medical Imagin

Integrating the Agricultural Sector into the New EU Climate Policy Framework for 2030: A Scenario Analysis to Highlight Potential Impacts and Challenges

According to the European Council's recent agreement on domestic climate and energy goals, greenhouse gas emissions from sectors outside the EU's Emission Trading Scheme have to be cut by 30% below 2005 levels by 2030. So far no decision has been taken on agriculture's specific involvement in mitigation obligations or on how mitigation targets would be distributed between Member States. Based on hypothetical assumptions, we employ the CAPRI model to illustrate and highlight some potential impacts and challenges related to an integration of the agricultural sector into the new EU climate policy framework. Results of the hypothetical mitigation policy scenario show important impacts on EU agriculture, in particular the livestock sector, if the distribution key of the current Effort Sharing Decision would be rigidly applied as in our assumptions. The results highlight the importance of a targeted but flexible implementation of mitigation policy instruments in the EU and its Member States, as well as the need for a wider consideration and adoption of technological mitigation options

An economic assessment of GHG mitigation policy options for EU agriculture

The report presents an overview of the historical and projected development of agricultural GHG emissions in the EU. The major objective of the report is to present the improvements made in the CAPRI modelling system with respect to GHG emission accounting and especially regarding the implementation of endogenous technological mitigation options. Furthermore, the CAPRI model was applied to provide a quantitative assessment of illustrative GHG mitigation policy options in the agricultural sector, and their production and economic implications.JRC.J.4-Agriculture and Life Sciences in the Econom

Identifying components required for OMP biogenesis as novel targets for antiinfective drugs

The emergence of multiresistant Gram-negative bacteria requires new therapies for combating bacterial infections. Targeting the biogenesis of virulence factors could be an alternative strategy instead of killing bacteria with antibiotics. The outer membrane (OM) of Gram-negative bacteria acts as a physical barrier. At the same time it facilitates the exchange of molecules and harbors a multitude of proteins associated with virulence. In order to insert proteins into the OM, an essential oligomeric membrane-associated protein complex, the ss-barrel assembly machinery (BAM) is required. Being essential for the biogenesis of outer membrane proteins (OMPs) the BAM and also periplasmic chaperones may serve as attractive targets to develop novel antiinfective agents. Herein, we aimed to elucidate which proteins belonging to the OMP biogenesis machinery have the most important function in granting bacterial fitness, OM barrier function, facilitating biogenesis of dedicated virulence factors and determination of overall virulence. To this end we used the enteropathogen Yersinia enterocolitica as a model system. We individually knocked out all non-essential components of the BAM (BamB, C and E) as well as the periplasmic chaperones DegP, SurA and Skp. In summary, we found that the most profound phenotypes were produced by the loss of BamB or SurA with both knockouts resulting in significant attenuation or even avirulence of Ye in a mouse infection model. Thus, we assume that both BamB and SurA are promising targets for the development of new antiinfective drugs in the future.Peer reviewe

Sustainable Transport Planning for Israel and Palestine

The paper presents the results of a trilateral research project carried out jointly by German, Israeli, and Palestinian institutions. The overall objective of the project was to develop and adapt models and tools for resource-preserving transport planning in the West Bank and the adjacent areas. Because of its high dynamics and the particular political circumstances, broader socio-economic and political considerations needed to be included in the analysis of present conditions and the exploration of future developments in this area. Compared to other countries, transport planning in Palestine is much more linked to sensitive issues such as security, Israeli settlements, bypass road s and checkpoints, which cannot always be separated in a clean way. To evaluate different policy options for transport planning, a modelling system has been developed consisting of a GIS database, integrated transport and environmental models and network extensions tools. The paper pres ents the integrated database and the modelling system developed, describes the scenarios implemented and compares the outcomes of the model runs with respect to their environmental and social impacts.The research project “GIS-Based Models and GIS-Tools for Sustainable Transport Planning in Israel and Palestine” was funded by the German Research Council (DFG) within the framework of their trilateral research programme bringing German, Israeli and Palestinian researchers together. The project was conducted in two phases. Phase 1 started in March 1997 and ended in February 1999. Phase 2 started in March 2000 and officially ended in February 2000. The project consortium wishes to thank the German Research Council for making this study possible through a generous research grant