Introducing memory versatility to enhance memory system performance, energy efficiency and reliability

Main memory system is facing increasingly high pressure from the advances of computation power scaling. Nowadays memory systems are expected to have much higher capacity than before. However, DRAM devices have limited scalability. Higher capacity usually translates to proportional hardware and power cost. Memory compression is a promising technology to prevent it from happening. Previous memory compression works are generally based on rigid data layout which limits their performance. We thus propose Flexible Memory which supports out-of-order memory block layout to lower compression-related overhead and improve performance. Besides, the cost of memory reliability also increases with capacity growth. Conventional error protection schemes utilizes Hamming-based SECDED code that comes with 12.5\% capacity and power overhead of entire memory system. However it is not necessary to protect whole memory system because some data is not critical or not sensitive to memory errors. Memory capacity and power used in protecting them is almost wasted. Therefore, Selective Error Protection is necessary to lower the cost of large scale memory protection. The method to select critical data and non-critical data has been proposed before, however a memory system design to support its partitioned memory is challenging and does not exist at that time. Therefore, we propose a memory system design that has the capability to maintain two or more partitions with different layout in main memory at the same time. This design makes SEP schemes a complete practical design. Even with selective error protection, supporting memory reliability is still hurting scaling of memory capacity. Fortunately, memory data has been proved to be very compressible. Most common applications are expected to free up enough space that can be used to store their own ECC code. For these applications, memory reliability incurs very low space and power overhead. However, combining ECC and memory compression is not trivial. It is difficult to achieve high percentage of coverage over entire memory when compressibility of different memory blocks varies a lot. We thus introduce Flexible ECC that is based on Flexible Memory to allow easier ECC code placement. When a block has more choices to store its ECC code, it is more likely to be covered by ECC. With Flexible ECC, a larger portion of memory can be covered by ECC codes whose storage overhead is lowered by memory compression

A Review of Researches on Blockchain

Analyzing 242 articles related to the study of blockchain which were published in China and abroad from 2014 to 2016, and from the aspects of literature sources, research subjects, research methods and western countries, the basic frame of blockchain research classification is put forward. Summarize the current blockchain technology progress, research limitations and future development trends. The research shows that the domestic research on the blockchain is more decentralized, non-systematic, and has not reached a certain research depth. What’s more, it is lack of quantitative analysis. Digital currency, Internet finance, and the risk of blockchain technology research will be the focus of future research

An Application Study on AI Educational Robots in Spoken English Exercises of Chinese Primary Schools

China’s primary schools offer limited English courses, and the society lacks the environment for naturally acquiring English in everyday life. Students typically have weak spoken English abilities and inadequate application of English. With the aim of addressing this issue, 79 fifth-graders from China’s Hangzhou L elementary school participated in a one-semester AI-assisted English-speaking practice experiment. The control class practiced spoken English by reading English texts aloud, whereas the experimental class practiced for 30 minutes a day using the “AI educational robots + graded picture books + role play” approach. According to the results of the experiment’s post-test, Chinese primary school students regarded the experimental class’s acquisition mode to be highly appealing, this approach was well accepted by both students and parents and brought enthusiasm and good effect of spoken English exercise. The experimental class’s average daily reading time for English role-play reading grew by about 30 minutes, the amount of reading increased by five times, the amount of time spent watching cartoons and playing video games fell by nearly 28 minutes, and the spoken English score climbed by 37 points, representing an increase of 82% when compared to the control class; Additionally, the standard level of pronunciation and intonation has increased by two grades, from “poor” to “good,” and the English final exam scores have increased by roughly 8%. However, there has not been a considerable change in the aforementioned control class indicators. This AI-assisted second language practice technique is affordable, efficient, and helpful and has good implications for second language acquisition in other countries

Physics Characterization of TLD-600 and TLD-700 and Acceptance Testing of New X-RAD 160 Biological X-Ray Irradiator

<p>Project 1: Physics characterization of TLD-600 and TLD-700</p><p>Purpose:</p><p>It is suggested that a pair of TLD-600 and TLD-700 can measure the exposure in neutron-photon mix fields. But the basic information of physics characterization of TLD-600 and 700 are not available. The purpose of this study was study the individual TLD variation and the energy dependence of TLD-600 and TLD-700. </p><p>Methods:</p><p>The individual calibration factors for 52 TLD-600 chips and 51 TLD-700 chips were determined under x-ray beams of 60 kVp, 80 kVp, 120 kVp, a mono-energetic 662 keV gamma beam of a Cs-137 source, and an Am-Be neutron beam (4.4 MeV). The individual calibration factor was calculated as the ratio of the group average response in uC/mR and the individual response in uC/mR. In addition, energy corrections factors for the individual calibration factors were determined, from each of the x-ray beams (60 kVp, 80 kVp, 120 kVp) to the 662 keV Cs-137 gamma beams.</p><p>Results:</p><p>For TLD-600, the range and relative standard deviation of the individual calibration factors are: 60 kVp (0.94003-1.0927, 3.5369%), 80 kVp (0.9395-1.0867, 3.0952%), 120 kVp (0.83403-1.0796, 4.5732%), 662 keV (0.80465-1.1926, 9.2515% ), AmBe (0.91740-0.94905, 3.0882% ); and the energy corrections factors relative to the 662 keV Cs-137 beams are: 60 kVp (1.2223), 80 kVp (1.1013), 120 kVp (1.0299).</p><p>For TLD-700 the range and relative standard deviation of the individual calibration factors are: 60 kVp (0.94351-1.0630, 2.6044%), 80 kVp (0.91690-1.0614, 2.6996%), 120 kVp (0.95697-1.0474, 2.3606%), 662 keV (0.91348-1.2270 , 4.2243%), AmBe (0.79330-1.2268 , 9.1577%); and the energy corrections factors relative to the 662 keV Cs-137 beams are: 60 kVp (1.0373), 80 kVp (0.97661), 120 kVp (0.88532).</p><p>Conclusion:</p><p>We have measured individual calibration factors and the average energy correction factors for photon beams and Am-Be neutron beams. Our results will be used in the future experiments and measurements with TLD-600 and TLD-700.</p><p>Project 2: Acceptance testing of new X-RAD 160 Biological X-Ray Irradiator</p><p>Purpose:</p><p>An X-RAD 160 Biological X-Ray Irradiator was recently installed at Duke University to serve as a key device for cellular radiobiology research. The purpose of this study is to perform acceptance testing on the new irradiator for operator radiation safety and irradiation specifications. </p><p> Methods:</p><p>The acceptance testing included tests of the following components: (1) Leakage radiation survey, (2) Half-value layer (beam quality), (3) Uniformity, (4) KVp accuracy, (5) Exposure at varying mA (linearity of mA), (6) Exposure at varying kVp, (7) Inverse square measurements, (8) Field size measurement, (9) Exposure constancy. </p><p>The irradiation parameters for each components of first round of acceptance testing performed on September 21, 2012 were: Leakage radiation survey (none, 160 kVp, 18 mA, 200s), Beam quality (40cm, 50-140 kVp in 10 kVp incensement, 1 mA, 10s, none), Uniformity (40cm, 160 kVp, 18 mA, 15s, F1), KVp accuracy (40cm, 50-150 kVp in 10 kVp incensement, 10 mA, 15s, none), Linearity of mA (40cm, 160 kVp, 2-18 mA, 15s, none), Inverse square measurements (20-63cm, 160 kVp, 1mA, 30s, none), Field size measurement (40cm, 160 kVp, 10 mA, 15s, none), Exposure constancy (40cm, 160 kVp, 18 mA, 20s, none). </p><p>The irradiation parameters for each components for each components of second round of acceptance testing performed on November 18, 2012 were: Beam quality (40cm, 35-150 kVp, 1 mA, 10s, F1) , KVp accuracy (40cm, 35-150 kVp, 1 mA, 10s, F1), Variation of kVp (40cm, 160 kVp, 18 mA, 30s, F1), Linearity of mA (40cm, 160 kVp, 1-18 mA, 30s, F1), Uniformity (40cm, 160 kVp, 18 mA, 30s, F1), Inverse square measurements (20-63cm, 160 kVp, 18 mA, 30s, F1).</p><p>Results: </p><p>The first round of acceptance testing performed on September 21, 2012 failed due to the fact that the measured exposure along the X-axis was significantly non-uniform; the exposure greatly decreases going in the left direction, which is a clear indication of un-corrected anode heel effect. After the X-ray tube was returned to the manufacturer, the beam was reconfigured by tilting the X-ray tube. Another round of acceptance testing was performed on December 18, 2012.</p><p>Conclusion:</p><p>The acceptance testing fulfilled the initial purpose. The machine is currently used normally In the following experiments; routine maintenance and quality assurance (QA) are required.</p>Thesi

Exploration on the Training Mode of Computer Professionals Based on the Concept of “New Engineering”

With the national industrial upgrading and technological innovation in recent years, the construction industry is leading in the direction of informatization, industrialization, intelligence and international integration, which puts forward new requirements for the current traditional mode of computer talent training. The innovation of talent training mode, the improvement of education and teaching, the improvement of education resources and so on have become the urgent problems of new engineering computer professional talent training Absolutely. This paper analyzes the current situation of "new engineering" talent demand and training, points out the shortcomings of the current computer talent training in the teaching concept, teaching mode, teachers and so on, and explores the new engineering computer talent training mode. And take the practice of Henan University School of civil engineering and architecture in the new engineering personnel training as an example, hope to have a certain reference significance for the new engineering computer professional personnel training. Keywords: new engineering; computer; interdisciplinary training; subject integration DOI: 10.7176/JEP/12-8-03 Publication date:March 31st 202

High yield expression of an AHL-lactonase from Bacillus sp. B546 in Pichia pastoris and its application to reduce Aeromonas hydrophila mortality in aquaculture

<p>Abstract</p> <p>Background</p> <p><it>Aeromonas hydrophila </it>is a serious pathogen and can cause hemorrhagic septicemia in fish. To control this disease, antibiotics and chemicals are widely used which can consequently result in "superbugs" and chemical accumulation in the food chain. Though vaccine against <it>A. hydrophila </it>is available, its use is limited due to multiple serotypes of this pathogen and problems of safety and efficacy. Another problem with vaccination is the ability to apply it to small fish especially in high numbers. In this study, we tried a new way to attenuate the <it>A. hydrophila </it>infection by using a quorum quenching strategy with a recombinant AHL-lactonase expressed in <it>Pichia pastoris</it>.</p> <p>Results</p> <p>The AHL-lactonase (AiiA_B546) from <it>Bacillus </it>sp. B546 was produced extracellularly in <it>P. pastoris </it>with a yield of 3,558.4 ± 81.3 U/mL in a 3.7-L fermenter when using 3-oxo-C8-HSL as the substrate. After purification with a HiTrap Q Sepharose column, the recombinant homogenous protein showed a band of 33.6 kDa on SDS-PAGE, higher than the calculated molecular mass (28.14 kDa). Deglycosylation of AiiA_B546with Endo H confirmed the occurrence of <it>N</it>-glycosylation. The purified recombinant AiiA_B546showed optimal activity at pH 8.0 and 20°C, exhibited excellent stability at pH 8.0-12.0 and thermal stability at 70°C, was firstly confirmed to be significantly protease-resistant, and had wide substrate specificity. In application test, when co-injected with A. <it>hydrophila </it>in common carp, recombinant AiiA_B546decreased the mortality rate and delayed the mortality time of fish.</p> <p>Conclusions</p> <p>Our results not only indicate the possibility of mass-production of AHL-lactonase at low cost, but also open up a promising foreground of application of AHL-lactonase in fish to control <it>A. hydrophila </it>disease by regulating its virulence. To our knowledge, this is the first report on heterologous expression of AHL-lactonase in <it>P. pastoris </it>and attenuating <it>A. hydrophila </it>virulence by co-injection with AHL-lactonase.</p