EdgeIso: Effective Performance Isolation for Edge Devices

© 2020 IEEE.Edges enable cloud services to be provided at low-latency and efficiently reduce the amount of transferred data by placing latency-critical tasks close to users. However, multi-tasking results in resource contention on edge devices, making it challenging to meet the service level objectives (SLOs) of tasks. Compared to the clouds, edges have relatively limited resources, but their tasks are required to meet a higher level of SLOs than clouds. Furthermore, modern edge devices equipped with additional accelerators (e.g., GPU) may worsen the resource contention due to the edge's integrated architecture, sharing the memory bandwidth between CPUs and accelerators. To address these challenges, we present EdgeIso, a light-weight scheduler that dynamically isolates the performance of tasks on edges. EdgeIso periodically monitors the resource contention and mitigates the contention to meet the SLOs of tasks by efficiently enforcing several isolation techniques (e.g., DVFS and core allocation) in an incremental manner. Moreover, it detects the changes of task executions or offered loads for tasks, thus handling high load fluctuations adaptively. We implement EdgeIso as a user-level scheduler on the Linux integrates into an NVIDIA Jetson TX2. Our experimental results show that EdgeIso improves the performance of the low-latency tasks significantly while improving resource efficiency compared with both the offloading and reservation scheme used in clouds.N

Catechol as a New Electron Hot Spot of Carbon Nitride

Graphitic carbon nitride (CNx) is a promising photocatalyst with visible-light sensitivity, attractive band-edge positions, tunable electronic structure, and eco-friendliness. However, their applications are limited by a low catalytic activity due to inefficient charge separation and insufficient visiblelight absorption. Here we show a new method to generate the electron polarization of CNx toward the edge via the chemical conjugation of catechol to CNx for enhanced photochemical activity. The electron-attracting property of catechol/quinone pairs induces the accumulation of photoexcited electrons at the edge of conjugated catechol-CNx hybrid nanostructure (Cat-CNx), , serving as an electron hot spot, as demonstrated by positive open-circuit photovoltage, which increases electron transfer through the conjugated catechol while suppressing charge recombination in the CNx. The catechol conjugation also widens the photoactive spectrum via the larger range delocalization of π-electrons. Accordingly, Cat-CNx reveals a 6.3 higher reductive photocurrent density than CNx. Gold ion reduction dramatically increased due to the enhanced electron transfer activity of Cat-CNx in cooperation with the inherent hydrophilicity and metal chelating property of catechols. Cat-CNx exhibits a 4.3 higher maximum adsorption capacity for gold ions under simulated sun light illumination compared to CNx. This work suggests that the post-modification of CNx’s π-conjugated system is a promising route to handle varied shortcomings and broaden availability of CNx

Label-free optical projection tomography for quantitative three-dimensional anatomy of mouse embryo

Recent progress in three-dimensional optical imaging techniques allows visualization of many comprehensive biological specimens. Optical clearing methods provide volumetric and quantitative information by overcoming the limited depth of light due to scattering. However, current imaging technologies mostly rely on the synthetic or genetic fluorescent labels, thus limits its application to whole-body visualization of generic mouse models. Here, we report a label-free optical projection tomography (LF-OPT) technique for quantitative whole mouse embryo imaging. LF-OPT is based on the attenuation contrast of light rather than fluorescence, and it utilizes projection imaging technique similar to computed tomography for visualizing the volumetric structure. We demonstrate this with a collection of mouse embryo morphologies in different stages using LF-OPT. Additionally, we extract quantitative organ information applicable toward high-throughput phenotype screening. Our results indicate that LF-OPT can provide multi-scale morphological information in various tissues including bone, which can be difficult in conventional optical imaging technique