104 research outputs found
Hierarchy and Balance: The Role of Monumentality in European and Indian Landscapes - An Archaeological and Anthropological Perspective
The use of ethnographic analogies for the construction of explanatory patterns and scientific narratives has a long history within archaeological research. While appropriate critique was raised with regard to the way analogies were used, the rise of critical perspectives within recent archaeological debates and discourses clearly highlights the need for a critical and reflective use of comparative analyses which will help us to go beyond a perception of archaeology as a cultural-historical science. The diversity and variability of the meaning of monumentality and megalith building in modern-day India shows the potential of such an approach and the importance of the integration of the perspectives of local communities without a direct link to scientific discourses. Monumentality and megalithic construction, due to the complexity and variance of this specific phenomenon, constitute a good example for the potential benefit and gain of the integration of comparative, ethnoarchaeological perspectives
Explaining YOLO: Leveraging Grad-CAM to Explain Object Detections
We investigate the problem of explainability for visual object detectors.
Specifically, we demonstrate on the example of the YOLO object detector how to
integrate Grad-CAM into the model architecture and analyze the results. We show
how to compute attribution-based explanations for individual detections and
find that the normalization of the results has a great impact on their
interpretation
Demonstrating Advantages of Neuromorphic Computation: A Pilot Study
Neuromorphic devices represent an attempt to mimic aspects of the brain's
architecture and dynamics with the aim of replicating its hallmark functional
capabilities in terms of computational power, robust learning and energy
efficiency. We employ a single-chip prototype of the BrainScaleS 2 neuromorphic
system to implement a proof-of-concept demonstration of reward-modulated
spike-timing-dependent plasticity in a spiking network that learns to play the
Pong video game by smooth pursuit. This system combines an electronic
mixed-signal substrate for emulating neuron and synapse dynamics with an
embedded digital processor for on-chip learning, which in this work also serves
to simulate the virtual environment and learning agent. The analog emulation of
neuronal membrane dynamics enables a 1000-fold acceleration with respect to
biological real-time, with the entire chip operating on a power budget of 57mW.
Compared to an equivalent simulation using state-of-the-art software, the
on-chip emulation is at least one order of magnitude faster and three orders of
magnitude more energy-efficient. We demonstrate how on-chip learning can
mitigate the effects of fixed-pattern noise, which is unavoidable in analog
substrates, while making use of temporal variability for action exploration.
Learning compensates imperfections of the physical substrate, as manifested in
neuronal parameter variability, by adapting synaptic weights to match
respective excitability of individual neurons.Comment: Added measurements with noise in NEST simulation, add notice about
journal publication. Frontiers in Neuromorphic Engineering (2019
Prevalence, Enabling Factors, and Clinical Outcome
Background: Striatocapsular infarcts (SCIs) are defined as large subcortical
infarcts involving the territory of more than one lenticulostriate artery. SCI
without concomitant ischemia in the more distal middle cerebral artery (MCA)
territory [isolated SCI (iSCI)] has been described as a rare infarct pattern.
The purpose of this study was to assess the prevalence of iSCI in patients
treated with endovascular thrombectomy (ET), to evaluate baseline and
procedural parameters associated with this condition, and to describe the
clinical course of iSCI patients. Methods: A retrospective analysis of 206
consecutive patients with an isolated MCA occlusion involving the
lenticulostriate arteries and treated with ET was performed. Baseline patient
and procedural characteristics and ischemic involvement of the striatocapsular
and distal MCA territory [iSCI, as opposed to non-isolated SCI (niSCI)] were
analyzed using multivariate logistic regression models. Prevalence of iSCI was
assessed, and clinical course was determined with the rates of substantial
neurological improvement and good functional short- and mid-term outcome
(discharge/day 90 Modified Rankin Scale ≤2). Results: iSCI was detected in 53
patients (25.7%), and niSCI was detected in 153 patients (74.3%). Successful
reperfusion [thrombolysis in cerebral infarction (TICI) 2b/3] [adjusted odds
ration (aOR) 8.730, 95% confidence interval (95% CI) 1.069–71.308] and good
collaterals (aOR 2.100, 95% CI 1.119–3.944) were associated with iSCI. In
successfully reperfused patients, TICI 3 was found to be an additional factor
associated with iSCI (aOR 5.282, 1.759–15.859). Patients with iSCI had higher
rates of substantial neurological improvement (71.7 vs. 37.9%, p < 0.001) and
higher rates of good functional short- and mid-term outcome (58.3 vs. 23.7%, p
< 0.001 and 71.4 vs. 41.7%, p < 0.001). However, while iSCI patients, in
general, had a more favorable outcome, considerable heterogeneity in outcome
was observed. Conclusion: High rates of successful reperfusion (TICI 2b/3) and
in particular, complete reperfusion (TICI 3) are associated with iSCIs. The
high prevalence of iSCI in successfully reperfused patients with good
collaterals corroborates previous concepts of iSCI pathogenesis. iSCI, once
considered a rare pattern of cerebral ischemia, is likely to become more
prevalent with increases in endovascular stroke therapy. This may have
implications for patient rehabilitation and pathophysiological analyses of
ischemic damage confined to subcortical regions of the MCA territory
Techno-Economic Assessment & Life-Cycle Assessment Guidelines for CO2 Utilization
NOTE: Updated version 1.1 available at http://hdl.handle.net/2027.42/162573
Climate change is one of the largest challenges of our time. One of the major causes of anthropogenic climate change, carbon dioxide, also leads to ocean acidification. Left unaddressed, these two challenges will alter ecosystems and fundamentally change life, as we know it. Under the auspices of the UN Framework Convention on Climate Change and through the Paris Agreement, there is a commitment to keep global temperature increase to well below two degrees Celsius. This will require a variety of strategies including increased renewable power generation and broad scale electrification, increased energy efficiency, and carbon-negative technologies.
We believe that Life Cycle Assessment (LCA) is necessary to prove that a technology could contribute to the mitigation of environmental impacts and that Techno-Economic Assessment (TEA) will show how the technology could be competitively delivered in the market. Together the guidelines for LCA and TEA that are presented in this document are a valuable toolkit for promoting carbon capture and utilization (CCU) technology development.Development of standardized CO2 Life Cycle and Techno-economic Assessment Guidelines was commissioned by CO2 Sciences, Inc., with the support of 3M, EIT Climate-KIC, CO2 Value Europe, Emissions Reduction Alberta, Grantham Foundation for the Protection of the Environment, R. K. Mellon Foundation, Cynthia and George Mitchell Foundation, National Institute of Clean and Low Carbon Energy, Praxair, Inc., XPRIZE and generous individuals who are committed to action to address climate change.https://deepblue.lib.umich.edu/bitstream/2027.42/145436/3/Global_CO2_Initiative_TEA_LCA_Guidelines-2018.pdf-
Improved Tensile Ductility by Severe Plastic Deformation for Nano-Structured Metallic Glass
The effect of severe plastic deformation by high-pressure torsion (HPT) on the structure and plastic tensile properties of two Zr-based bulk metallic glasses, Zr55.7Ni10Al7Cu19Co8.3 and Zr64Ni10Al7Cu19, was investigated. The compositions were chosen because, in TEM investigation, Zr55.7Ni10Al7Cu19Co8.3 exhibited nanoscale inhomogeneity, while Zr64Ni10Al7Cu19 appeared homogeneous on that length scale. The nanoscale inhomogeneity was expected to result in an increased plastic strain limit, as compared to the homogeneous material, which may be further increased by severe mechanical work. The as-cast materials exhibited 0.1% tensile plasticity for Zr64Ni10Al7Cu19 and Zr55.7Ni10Al7Cu19Co8.3. Following two rotations of HPT treatment, the tensile plastic strain was increased to 0.5% and 0.9%, respectively. Further testing was performed by X-ray diffraction and by differential scanning calorimetry. Following two rotations of HPT treatment, the initially fully amorphous Zr55.7Ni10Al7Cu19Co8.3 exhibited significantly increased free volume and a small volume fraction of nanocrystallites. A further increase in HPT rotation number did not result in an increase in plastic ductility of both alloys. Possible reasons for the different mechanical behavior of nanoscale heterogeneous Zr55.7Ni10Al7Cu19Co8.3 and homogeneous Zr64Ni10Al7Cu19 are presented
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