2,424 research outputs found
Energy-Efficient Streaming Using Non-volatile Memory
The disk and the DRAM in a typical mobile system consume a significant fraction (up to 30%) of the total system energy. To save on storage energy, the DRAM should be small and the disk should be spun down for long periods of time. We show that this can be achieved for predominantly streaming workloads by connecting the disk to the DRAM via a large non-volatile memory (NVM). We refer to this as the NVM-based architecture (NVMBA); the conventional architecture with only a DRAM and a disk is referred to as DRAMBA. The NVM in the NVMBA acts as a traffic reshaper from the disk to the DRAM. The total system costs are balanced, since the cost increase due to adding the NVM is compensated by the decrease in DRAM cost. We analyze the energy saving of NVMBA, with NAND flash memory serving as NVM, relative to DRAMBA with respect to (1) the streaming demand, (2) the disk form factor, (3) the best-effort provision, and (4) the stream location on the disk. We present a worst-case analysis of the reliability of the disk drive and the flash memory, and show that a small flash capacity is sufficient to operate the system over a year at negligible cost. Disk lifetime is superior to flash, so that is of no concern
How migrating 0.0001% of address space saves 12% of energy in hybrid storage
We present a simple, operating-\ud
system independent method to reduce the num-\ud
ber of seek operations and consequently reduce\ud
the energy consumption of a hybrid storage\ud
device consisting of a hard disk and a ļ¬ash\ud
memory. Trace-driven simulations show that\ud
migrating a tiny amount of the address space\ud
(0.0001%) from disk to ļ¬ash already results\ud
in a signiļ¬cant storage energy reduction (12%)\ud
at virtually no extra cost. We show that the\ud
amount of energy saving depends on which part\ud
of the address space is migrated, and we present\ud
two indicators for this, namely sequentiality and\ud
request frequency. Our simulations show that\ud
both are suitable as criterion for energy-saving\ud
ļ¬le placement methods in hybrid storage. We\ud
address potential wear problems in the ļ¬ash\ud
subsystem by presenting a simple way to pro-\ud
long its expected lifetime.\u
MOLECULAR AND CHEMICAL THERAPEUTIC FEATURES OF URTICA SPECIES
The present review study was conducted to review the current understanding of molecular aspects of Urtica species. We refer to the most recent published articles addressing the therapeutic potential of this plant. A wide spectrum of diseases has been associated with Urtica species including cancer, arthritis, autoimmune diseases, diabetes, and fatigue. Some molecular mechanisms and chemical properties have been discussed. Taken together, studies have confirmed the beneficial effects of Urtica all over the world and understanding of the molecular mechanisms underlying the beneficial effects opens new horizon to understand new therapeutic options. The extracts of Urtica should be prepared based on separating effective ingredients for optimal therapeutic benefits
E-Government Systems Success and User Acceptance in Developing Countries: The Role of Perceived Support Quality
Measuring the Performance of the Kuwaiti Banking Sector Before and After the Recent Financial Crisis
The objective of this research is to investigate the determinants of the performance of the Kuwaiti banking sector before and after the recent financial crisis over the period of 2006-2012. The data utilized is based on the yearly financial statements of the Kuwaiti banks that are listed on Kuwait Stock Exchange over the same period. There are several methods have been used to identify the determinants which impact the performance of the banking sector. In this research, a ratio analysis technique is considered efficient and more reliable method than other approaches. Other factors such as trend, government regulations and other economic factors are also included. The study found that the overall banking sector performance increased considerably in the first two years of the analysis. A significant change in trend is noticed at the onset of the global financial crisis in September 2008, reaching its peak before the global financial crisis. This resulted in decreasing the profitability, return on equity, assets and capital. Keywords: Banking Sector, Financial Performance, Financial ratios, Interest Spread Rate, Kuwait Stock Exchange (KSE), Growth Ratios, Financial Crisis
Characterization and functional roles of paternal RNAs in 2–4 cell bovine embryos
Embryos utilize oocyte-donated RNAs until they become capable of producing RNAs through embryonic genome activation (EGA). The sperm\u2019s influence over pre-EGA RNA content of embryos remains unknown. Recent studies have revealed that sperm donate non-genomic components upon fertilization. Thus, sperm may also contribute to RNA presence in pre-EGA embryos. The first objective of this study was to investigate whether male fertility status is associated with the RNAs present in the bovine embryo prior to EGA. A total of 65 RNAs were found to be differentially expressed between 2\u20134 cell bovine embryos derived from high and low fertility sires. Expression patterns were confirmed for protein phosphatase 1 regulatory subunit 36 (PPP1R36) and ataxin 2 like (ATXN2L) in three new biological replicates. The knockdown of ATXN2L led to a 22.9% increase in blastocyst development. The second objective of this study was to characterize the parental origin of RNAs present in pre-EGA embryos. Results revealed 472 sperm-derived RNAs, 2575 oocyte-derived RNAs, 2675 RNAs derived from both sperm and oocytes, and 663 embryo-exclusive RNAs. This study uncovers an association of male fertility with developmentally impactful RNAs in 2\u20134 cell embryos. This study also provides an initial characterization of paternally-contributed RNAs to pre-EGA embryos. Furthermore, a subset of 2\u20134 cell embryo-specific RNAs was identified
Basic skin surgery interactive simulation: system description and randomised educational trial
Background: Learning the skills required for open surgery is essential for trainee progression towards more advanced technical procedures. Simulation supports skill enhancement at a time when exposure to actual surgical procedures and traditional apprentice-based teaching has declined. The proliferation of smartphone and tablet devices with rich, touch sensitive displays and increasing processing power makes a compelling argument for expanding accessibility further by development of mobile virtual simulations for training on demand in any setting, at any time.We present a tablet-based mobile simulation App for educating surgical trainees in the planning and surgical procedures involved in facial lesion resection and local skin flap surgery. Methods: Novel algorithms were developed and modules included in a mobile simulation App to teach concepts required for three defect reconstruction techniques: elliptical closure, bilateral advancement (H flap) and the semi-circular rotation flap, with additional resources such as videos and formal guidelines made available at relevant points in the simulation. A randomised educational trial was conducted using the mobile simulation App with 18 medical students that were divided equally into two groups: the intervention group learning using the new mobile simulation App, and a control group, undergoing traditional text-based self-study. The students were then assessed on knowledge and skills' acquisition through an MCQ and a task analysis score. Results: There was a statistically significant difference between the scores of students in the intervention group and the students in the non-intervention group in both forms of assessment, with an average multiple-choice assessment score of 62.95% points versus 56.73%, respectively (pĀ =ā0.0285), and an average task analysis score of 3.53 versus 2.58, respectively (pĀ =ā0.0139). Conclusions: Touch-based simulation provided an efficient and superior method of learning three different local flap techniques for facial soft tissue reconstruction, and helped recalling steps involved in the surgery in a fluid manner that also improved task performance
Analysis of Implementation Methodologies of Deadbeat Direct-Torque and Flux Control (DB-DTFC) for IPMSMs in Stationary and Rotatory Reference Frames
Deadbeat-control is a well-established control technique that uses the inverse machine model to determine the voltage commands required to achieve the desired torque and flux commands. Its classic implementation requires solving a quadratic equation with an extensive number of terms. Moreover, it can be only solved in the dq-reference frame. In this paper, two novel implementations are presented. The first methodology, in the dq-reference frame, reduces the algorithm's complexity and computation time. Moreover, it is immune to estimation errors of the permanent magnet flux. A second methodology based on the flux vector orientation is also presented. As opposed to the classic implementation, the proposed method does not require solving a quadratic equation; this reduces its complexity and computation time. Furthermore, the proposed methodology can be solved both in the dq and aĆ frames since it relies only on the stator flux's magnitude and angle. Up to date and to the best of the author's knowledge, DB-DTFC in the stationary frame has not been presented before for salient machines. DB-DTFC in the stationary frame reduces the reliance on the position observer and facilitates the implementation of overmodulation techniques and six-step operation. The proposed methodology can operate in the MTPF line without any adjustments and it shows an adequate dynamic performance. Simulation and experimental results validate the methodologies. Caveats regarding their implementation are also discussed
Shutdown Policies for MEMS-Based Storage Devices -- Analytical Models
MEMS-based storage devices should be energy ecient for deployment in mobile systems. Since MEMS-based storage devices have a moving me- dia sled, they should be shut down during periods of inactivity. However, shutdown costs energy, limiting the applicability of aggressive shutdown decisions. The media sled in MEMS-based storage devices is suspended by springs. We introduce a policy that exploits the spring structure to reduce the shut- down energy. As a result, the aggressiveness of the shutdown decisions can be increased, reducing the energy consumption. This report devises analytical models of the shutdown time and energy of this policy
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