371 research outputs found
ACTS in Need: Automatic Configuration Tuning with Scalability Guarantees
To support the variety of Big Data use cases, many Big Data related systems
expose a large number of user-specifiable configuration parameters. Highlighted
in our experiments, a MySQL deployment with well-tuned configuration parameters
achieves a peak throughput as 12 times much as one with the default setting.
However, finding the best setting for the tens or hundreds of configuration
parameters is mission impossible for ordinary users. Worse still, many Big Data
applications require the support of multiple systems co-deployed in the same
cluster. As these co-deployed systems can interact to affect the overall
performance, they must be tuned together. Automatic configuration tuning with
scalability guarantees (ACTS) is in need to help system users. Solutions to
ACTS must scale to various systems, workloads, deployments, parameters and
resource limits. Proposing and implementing an ACTS solution, we demonstrate
that ACTS can benefit users not only in improving system performance and
resource utilization, but also in saving costs and enabling fairer
benchmarking
Flat-Foot Dynamic Walking via Human-Inspired Controller Design
This thesis describes a torque control scheme unifying feedback PD control and feed-forward impedance control to realize human-inspired walking on a novel planar footed bipedal robot: AMBER2. It starts with high fidelity modeling of the robot including nonlinear dynamics, motor model, and impact dynamics. Human data is then used by an optimization algorithm to produce a human-like walking gait that can be implemented on the robot, which is represented in the form of canonical walking functions. To realize the bipedal walking, first a PD controller is utilized to track the optimized trajectory. Next, impedance control parameters are estimated from the experimental data of a successful walking with AMBER2. Finally, the unified PD, impedance torque control law is experimentally realized on the bipedal robot AMBER2. Through the evidence of sustainable and unsupported walking achieved on AMBER2 showing high consistency with the simulated walking gait, the feasibility of AMBER2 walking scheme will be verified
BestConfig: Tapping the Performance Potential of Systems via Automatic Configuration Tuning
An ever increasing number of configuration parameters are provided to system
users. But many users have used one configuration setting across different
workloads, leaving untapped the performance potential of systems. A good
configuration setting can greatly improve the performance of a deployed system
under certain workloads. But with tens or hundreds of parameters, it becomes a
highly costly task to decide which configuration setting leads to the best
performance. While such task requires the strong expertise in both the system
and the application, users commonly lack such expertise.
To help users tap the performance potential of systems, we present
BestConfig, a system for automatically finding a best configuration setting
within a resource limit for a deployed system under a given application
workload. BestConfig is designed with an extensible architecture to automate
the configuration tuning for general systems. To tune system configurations
within a resource limit, we propose the divide-and-diverge sampling method and
the recursive bound-and-search algorithm. BestConfig can improve the throughput
of Tomcat by 75%, that of Cassandra by 63%, that of MySQL by 430%, and reduce
the running time of Hive join job by about 50% and that of Spark join job by
about 80%, solely by configuration adjustment
High MB solution degradation efficiency of FeSiBZr amorphous ribbon with surface tunnels
© 2020 by the authors. The as spun amorphous (Fe78Si9B13)99.5Zr0.5 (Zr0.5) and (Fe78Si9B13)99Zr1 (Zr1) ribbons having a Fenton-like reaction are proved to bear a good degradation performance in organic dye wastewater treatment for the first time by evaluating their degradation efficiency in methylene blue (MB) solution. Compared to the widely studied (Fe78Si9B13)100Zr0 (Zr0) amorphous ribbon for degradation, with increasing cZr (Zr atomic content), the as-spun Zr0, Zr0.5 and Zr1 amorphous ribbons have gradually increased degradation rate of MB solution. According to δc (characteristic distance) of as-spun Zr0, Zr0.5 and Zr1 ribbons, the free volume in Zr1 ribbon is higher Zr0 and Zr0.5 ribbons. In the reaction process, the Zr1 ribbon surface formed the 3D nano-porous structure with specific surface area higher than the cotton floc structure formed by Zr0 ribbon and coarse porous structure formed by Zr0.5 ribbon. The Zr1 ribbon\u27s high free volume and high specific surface area make its degradation rate of MB solution higher than that of Zr0 and Zr0.5 ribbons. This work not only provides a new method to remedying the organic dyes wastewater with high efficiency and low-cost, but also improves an application prospect of Fe-based glassy alloys
Challenges and Strategy Design for the Globalization of Traditional Chinese Drugs
As economic exchange has deepened in the international community, traditional Chinese drugs have gone global and gained a share in overseas markets. However, due to internal and external restrictions, only a small proportion of traditional Chinese drugs can gain access to mainstream drug markets in foreign countries. This article designs strategies and provides suggestions for globalizing the presence of traditional Chinese drugs based on an analysis of the current conditions and challenges of this globalization process
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