Non-Uniform APSK Optimization for BICM Systems

Traditional Amplitude Phase Shift Keying(APSK) consists of rings with points uniformly spaced. By giving up this uniform-spacing feature, we propose an APSK optimization method based on the uniform APSK with Gray labeling(Gray-APSK). The aim of the optimization is to maximize the Generalized Mutual Information(GMI)of Bit-Interleaved Coded Modulation(BICM) for the targeted code rate and channel. We show that our optimized non-uniform APSK could offer further performance gain compared with the conventional uniform Gray-APSK and considerably outperforms the traditional quadrature amplitude modulation at the targeted SNR and channel.     

FlexCore: Dynamic Virtual Machine Scheduling Using VCPU Ballooning

As multi-core processors become the de-facto configuration in modern computers, the adoption of SMP Virtual Machines(VMs) has been increasing, allowing for more efficient use of computing resources. However,because of existence of schedulers in both the hypervisor and the guest VMs, this creates a new research problem,viz., double scheduling. Although double scheduling may cause many issues including lock-holder preemption,v CPU stacking, CPU fragmentation, and priority inversion, prior approaches have either introduced new problems and/or addressed the problem incompletely. In this paper, we describe the design and implementation of Flex Core,a new scheduling scheme using v CPU ballooning, which dynamically adjusts the number of v CPUs of a VM at runtime. This essentially eliminates unnecessary scheduling in the hypervisor layer, and thus, boosts performance significantly. An evaluation using a complete KVM-based implementation shows that the average performance improvement for PARSEC applications on a 12-core Intel machine is approximately 52.9%, ranging from 35.4% to79.6%.     

干旱胁迫对苦荞麦农艺性状、产量和品质的影响

以2个苦荞品种(晋荞2号和川荞1号)为材料,研究了干旱胁迫对苦荞麦农艺性状、产量和品质的影响.结果表明:晋荞2号在轻度胁迫处理下株高、主根长、根体积、侧根数分别为56.4cm,12.41cm,3.76cm3和13.0个,较正常灌水和重度胁迫处理分别增加13.4%~42.8%,22.3%~73.4%,16.4%~50.5%和33.1%~77.6%.川荞1号在轻度胁迫处理下株高、主根长、根体积和侧根数分别为35.1cm,16.3cm,3.66cm3和6.0个.较正常灌水和重度胁迫处理分别增加9.4%~33.3%,40.4%~50.0%;23.2%~46.5%,34.5%~69.7%.胁迫可增加苦荞的单株粒质量,两个品种均在轻度胁迫处理单株粒质量最高,分别为2.3g和2.3g.芦丁质量分数以叶片质量分数最高,但各胁迫处理间差异无统计学意义.黄酮质量分数以轻度胁迫处理最高,两个品种均以胁迫处理显著高于正常灌水处理,晋荞2号各器官间黄酮和芦丁质量分数均明显高于川荞1号.     

模拟结果为什么比实际更暖:简化气候模型结果（英文）

设计了一个非专业人士能够使用、最简化的气候敏感模型,用来研究人类活动所导致的全球变暖的幅度问题.在1990年的第一次IPCC评估报告中,IPCC对其报告中预测的未来全球变暖幅度很有信心,但是随后的观测结果显示全球的变暖幅度只有预测的一半.而自2001年起,全球变暖出现停滞,但是仅仅考虑到二氧化碳浓度的增加,很少有模型能够模拟出这一变化.在已出版的IPCC第五次评估报告的草稿中,IPCC大幅度削减了近期变暖的幅度,并以专家评估代替了模型预测.但是报告中关于未来气候长期变化的预测仍被保留.如果把IPCC模型的总反馈从1.9 W m–2 K–1调整到1.5 W m–2 K–1,气候敏感模型中模拟的温度将从3.2 K降至2.2 K.同时由于反馈很可能是净负反馈,更合适的估计应该是1.0 K.1.0 K是一个能够实现的增幅,21世纪的实际变暖将会小于1 K.即使燃烧所有可开采的化石燃料也不会使全球变暖的幅度超过2.2 K,这一增加幅度也将趋于平稳.本文认为解决IPCC第四、五次报告中评估方法的差异非常关键.一旦这些差异得到解决,人类活动导致的全球变暖在22世纪以及几个世纪以后的平稳态将有可能不会超过IPCC当前模型预测的1/3~1/2.     

《大数据百科全书》术语特点及收录与处理原则

大数据发展日新月异,新的应用需求和实践问题层出不穷,社会各界越来越重视大数据的基础研究。百科全书作为知识门类的概述性著作,是开展和推动基础研究的重要载体。作为大数据知识传播的工具,《大数据百科全书》不仅要有实用与新颖兼备的知识内容,并且还应具备准确严谨与通畅易懂的专业化语言文字表达。其中,术语是《大数据百科全书》不可或缺的有机组成部分,文章总结大数据领域的术语特点,并以此提出《大数据百科全书》术语方面的收录和处理原则。     

Land-atmosphere coupling amplifies hot extremes over China

Climate extremes, such as extreme hot temperatures and heat waves, can have dramatic societal, economic, and ecological consequences. China has experienced remarkable interannual and decadal changes in hot extremes during the last several decades. However, the underlying mechanisms responsible for changes in the hot extremes over China have not been clearly identified. In this study, we investigate the role of land-atmosphere coupling for hot days and heat waves during summer over China using two long-term ...     

反相高效液相色谱法测定化妆品中的酮麝香

 酮麝香是化妆品中的限用物质,对人体有致癌作用,因此,有必要对其含量进行分析。采用超声辅助提取法对不同基质类型的化妆品样品进行预处理。利用反相高效液相色谱法测定化妆品中的酮麝香。色谱条件为Kromasil C₁₈(250mm×4.6mm i.d.,5μm)色谱柱,流动相V(乙腈):V(水)= 80:20,流速1.0mL/min,检测波长235nm。结果表明,在此条件下,酮麝香在0.5-150 μg/mL范围内与相应的峰面积具有良好的线性关系(相关系数r为0.9998),线性回归方程为A=13500ρ-4829,回收率为90.5%-102.5%,RSD为0.45%-0.98%。因此,研究建立的利用反相高效液相色谱法测定化妆品中的酮麝香的方法准确、可靠、适用性广,可为酮麝香的分析及国家相关法规的制定提供一定的参考。     

Fine-mapping of SRT7 for short roots and identification of its candidate in rice

Three allelic short root mutants were identified by screening mutants with defective root elongation of the rice japonica cultivar Nipponbare mutant library generated via 60 Co γ-ray irradiation mutagenesis. These mutants, designated srt7-1 (short root 7-1), srt7-2 and srt7-3, respectively, had an extremely short seminal root, adventitious roots and lateral roots. Histological observation revealed the cell length of srt7 mutant roots was significantly shorter than that of wild-type roots. Genetic analysis i...     

Magnetocaloric effect in Er-Al-Co bulk metallic glasses

A series of Er-Al-Co bulk metallic glasses (BMGs) have been prepared by the copper mold casting method. The glass forming ability and magnetocaloric effect (MCE) for these alloys have been investigated. The second-order magnetic transition from para-magnetic to ferromagnetic states takes place at about 9 K. These BMGs exhibit excellent MCE because of their large effective magneton number; Er56Al24Co20 BMG has a maximum entropy change and refrigeration capacity of 16.06 J kg-1 K-1 and 546 J kg-1,respectively...