No abstract

Solid state drives (SSDs) are normally constructed with a number of parallel-accessible flash chips, where host I/O requests are processed in parallel. In addition, there are many internal activities in SSDs, such as garbage collection and wear leveling induced read, write, and erase operations, to solve the issues of inability of in-place updates and limited lifetime. When internal activities are triggered on a chip, the chip will be blocked. Our preliminary studies on several workloads show that when internal activities are frequently triggered, the host I/O performance will be significantly impacted because of the access conflict between them. In this work, in order to improve the access conflict induced performance degradation, a novel access conflict minimization scheme is proposed. The basic idea of the scheme is motivated by an interesting observation in SSDs: several chips are idle when other chips are busy with internal activities and host I/O requests. Based on this observation, we propose to schedule internal activities induced operations for minimized access conflict by exploiting the idleness of the multiple chips of SSDs. This approach is realized by two steps: First, read internal activities accessed data to the controller; second, by exploiting the idle chips during internal activities, write internal activities accessed data back to these idle chips. With this scheme, the internal activities can be processed with minimized access conflict to the host requests. Simulation results show that the proposed approach significantly reduces the access conflict, and in turn leads to a significant performance improvement of SSDs.

In order to study the effect of stress changes on cell adhesion, HUVEC, and MCF-7 cells were treated with simulated microgravity effect (SMG) and overloading (OL). Methods: Rotating Wall Vessel (2D-RWVS) bioreactor was used to create different culture conditions. In addition, the alteration of cell adhesion states, adhesion proteins, and relating factors of adhesion molecules under these two conditions were detected using cell adhesion assay, immunofluorescence, western blot, and qRT-PCR technology. Results: The results showed that the adhesion of cells decreased under SMG, while increased under OL. The expressions of integrin β1, paxillin, and E-cadherin under SMG condition were down-regulated as compared to that of the control group showing a time-dependent pattern of the decreasing. However, under OL condition, the expressions of adhesion proteins were up-regulated as compared to that of the control group, with a time-dependent pattern of increasing. EMT transcription factors Snail, twist, and ZEB1 were up-regulated under SMG while down-regulated under OL. Conclusion: Collectively our results indicated that cells could respond to stress changes to regulate the expressions of adhesion proteins and adapt their adhesion state to the altered mechanical environment. The altered cell adhesion in response to the mechanical stress may involve the changed expression of EMT-inducing factors, Snail, Twist, and ZEB1under the SMG/OL conditions.

This work proposes a novel data-driven mechanism for prediction of wastewater treatment results through mixture of two neural network models.