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Paying Attention to the Algorithm Behind the Curtain: Bringing Transparency to YouTube’s Demonetization Algorithms
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Abstract The UN's Paris Agreement goal of keeping global warming between 1.5 and 2°C is dangerously obsolete and needs to be replaced by a commitment to restore Earth's climate. We now know that continued use of fossil fuels associated with 1.5–2°C scenarios would result in hundreds of millions of pollution deaths and likely trigger multiple tipping elements in the Earth system. Unexpected advances in renewable power production and storage have radically expanded our climate response capacity. The cost of renewable technologies has plummeted at least 30‐year faster than projected, and renewables now dominate energy investment and growth. Thisrenewable revolutioncreates an opportunity and responsibility to raise our climate ambitions. Rather than aiming for climate mitigation—making things less bad—we should commit to climate restoration—a rapid return to Holocene‐like climate conditions where we know humanity and life on Earth can thrive. Based on observed and projected energy system trends, we estimate that the global economy could reach zero emissions by 2040 and potentially return atmospheric CO2to pre‐industrial levels by 2100–2150. However, this would require an intense and sustained rollout of renewable energy and negative emissions technologies on very large scales. We describe these clean electrification scenarios and outline technical and socioeconomic strategies that would increase the likelihood of restoring a Holocene‐like climate in the next 100 years. We invite researchers, policymakers, regulators, educators, and citizens in all countries to share and promote this positive message of climate restoration for human wellbeing and planetary stability.more » « less
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Hardware faults are a known source of security vulnerabilities. Fault injection in secure embedded systems leads to information leakage and privilege escalation, and countless fault attacks have been demonstrated both in simulation and in practice. However, there is a significant gap between simulated fault attacks and physical fault attacks. Simulations use idealized fault models such as single-bit flips with uniform distribution. These ideal fault models may not hold in practice. On the other hand, practical experiments lack the white-box visibility necessary to determine the true nature of the fault, leading to probabilistic vulnerability assessments and unexplained results. In embedded software, this problem is further exacerbated by the layered abstractions between the hardware (where the fault originates) and the application software (where the fault effect is observed). We present FaultDetective, a method to investigate the root-cause of fault injection from fault detection in software. Our main insight is that fault detection in software is only the end-point of a chain of events that starts with a fault manifestation in hardware and propagates through the micro-architecture and architecture before reaching the software level. To understand the fault effects at the hardware level, we use a scan chain, a low-level hardware test structure. We then use white-box simulation to propagate and observe hardware faults in the embedded software. We efficiently visualize the fault propagation across abstraction levels using a hash-tree representation of the scan chain. We implement this concept in a multi-core MSP430 micro-controller that redundantly executes an application in lock-step. With this setup, we observe the fault effects for several different stressors, including clock glitching and thermal laser stimulation, and explain the root-cause in each case.more » « less
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The circulation of the abyssal ocean is thought to be sustained by turbulence over a rough seafloor. Over sloping topography, this bottom-enhanced mixing produces diapycnal upwelling within a thin bottom boundary layer and downwelling aloft. Simplified theories have been developed to understand this local response to mixing, for example, by assuming an along-slope symmetry and imposing a constraint on the cross-slope transport. Ultimately, the local response to mixing on slopes must be connected to the basin-scale circulation; however, the barotropic transport must conserve potential vorticity. This coupling between the local response to mixing and the basin-scale circulation is studied here in the context of an idealized bowl-shaped basin using boundary layer theory and numerical solutions of the planetary geostrophic equations. In the absence of wind forcing and the joint effect of baroclinicity and relief (JEBAR), the leading-order barotropic transport is directed alongf/Hcontours, wherefis the planetary vorticity andHis the depth. The local response to mixing is coupled to this barotropic circulation. It can be thought of as simultaneously constrained by the barotropic circulation and forcing it via a bottom stress curl. Iff/Hcontours are closed, a strong barotropic circulation spins up along them as in simplified theories of the local response in the absence of along-slope variations. If these contours intersect the boundary, a case more typical in the real ocean, the barotropic transport is suppressed. This decouples the leading-order local response from the large-scale circulation and intensifies bottom boundary layer upwelling.more » « less
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