PsmArena: Partitioned Shared Memory for NUMA-Awareness in Multithreaded Scientific Applications

The Distributed Shared Memory(DSM) architecture is widely used in today's computer design to mitigate the ever-widening processing-memory gap, and it inevitably exhibits Non-Uniform Memory Access(NUMA) to shared-memory parallel applications. Failure to adapt to the NUMA effect can significantly downgrade application performance, especially on today's manycore platforms with tens to hundreds of cores. However, traditional approaches such as first-touch and memory policy fall short in false page-sharing, fragmentation, or ease of use. In this paper, we propose a partitioned shared-memory approach that allows multithreaded applications to achieve full NUMA-awareness with only minor code changes and develop an accompanying NUMA-aware heap manager which eliminates false page-sharing and minimizes fragmentation. Experiments on a 256-core cc-NUMA computing node show that the proposed approach helps applications to adapt to NUMA with only minor code changes and improves the performance of typical multithreaded scientific applications by up to 4.3 folds with the increased use of cores.     

基于耳蜗图多示例分析的音频场景分类模型

音频场景分类(Acoustic Scene Classification, ASC)是计算听觉场景领域最具挑战的任务之一。传统的ASC模型大多采用基于线性频率分析的手工特征加基于深度学习的分类模型方法。然而,一方面,由于基于线性频率分析的特征提取方法无法模拟人耳基底膜的非线性频率选择特性,从而造成特征分辨率低下的问题;另一方面,现有的分类模型无法解决由于音源复杂且音频事件高度重叠所造成的分类准确率低下的问题。为了解决以上问题,提出了基于耳蜗图多示例分析的音频场景分类模型,一方面采用中心频率按照等效带宽均匀分布的余弦滤波器组对信号频谱进行滤波以模拟人耳听觉感知特性;另一方面,通过引入多示例学习刻画整个数据结构的特点以提高分类准确率。此外,为了抵抗音频事件的频移影响,在多示例学习分类模型的分类预测整合器中采用平均池化方法。在DCASE 2018和DCASE 2019竞赛所提供的Task1a数据集上的实验结果表明,本文提出的模型比DCASE 2018竞赛所提供的基线系统以及传统的基于Log Mel特征提取和多示例学习的模型实现了更高的分类准确率,同时也验证了平均池化要优于最大池化。     

0.18m CMOS中用于频率综合的时间数字转换器

该文提出一种应用于全数字锁相环高分辨率的时间数字转换器TDC。该TDC延时单元由两级特殊的反相器构成,其中第一个反相器只考虑上升沿,而第二个反相器只考虑下降沿,通过合理选择两级反相器的尺寸可使总延时小于传统延时单元的一半,从而提高了TDC的分辨率。针对这种只考虑单沿的延时单元,该文还提出了相应的TDC系统。实验结果表明,在0.18μm CMOS工艺下,该文提出TDC的分辨率能达到28 ps。     

A Low Power Error Detection in the Syndrome Calculator Block for Reed-Solomon Codes: RS(204,188)

Reed-Solomon (RS) codes have been widely adopted in many modern communication systems. This paper describes a new method for error detection in the syndrome calculator block of RS decoders. The main feature of this method is to prove that it is possible to compute only a few syndrome coeffi-cients — less than half — to detect whether the codeword is correct. The theoretical estimate of the prob-ability that the new algorithm failed is shown to depend on the number of syndrome coefficients computed. The algo...     

中国古代丧服制度的政治内涵——父为长子服斩衰的讨论

在《仪礼·丧服》所规定的十一种服斩衰的情况中,父为长子服斩衰非常特殊,其不符合古代的三纲原则。丧服制度的根本精神和社会内涵是封建宗法制度,进一步而言,这种制度是为了维护政治秩序和社会稳定。宗法制度的核心和基础是嫡长子继承制,嫡长子承担着"传重"的特殊地位,是息纷止争的关键因素。所以,父为长子服斩衰深刻地反映了丧服制度所要表达的政治内涵。     

一类解非线性方程的高阶解法

本文建立了一类新的解非线性方程一般高阶解法.与牛顿方法和其它方法相比,收敛阶数和效率指数均有所提高.     

鸟类起源研究取得重大进展

鸟类起源于兽脚类恐龙的假说得到了广泛承认,但鸟类起源研究方向依然存在许多薄弱环节,主要包括鸟类手指同源问题、兽脚类分异时间框架问题以及羽毛起源和早期演化的一些问题。我们近年来在这些问题上取得了一系列重要进展。化石资料显示,兽脚类恐龙在向鸟类进化当中,其外侧两指退化;而现代发育学证据表明,鸟类手指是两侧退化,保留了中间3指。我们通过研究新疆侏罗系地层中发现的泥潭龙,提出了一种外侧和两侧退化模式结合的新假说。该假说可以解释古生物学与发育学资料之间的矛盾。我们报道的一件产自辽宁中上侏罗统髫髻山组的近鸟龙化石,代表了早于始祖鸟的带羽毛的物种,我们提出了包括鸟类在内的主要兽脚类恐龙类群出现于中侏罗世的一个快速演化事件,解决了有关鸟类兽脚类恐龙起源假说的时间悖论问题。我们报道了在北票龙化石中发现的一种新的原始羽毛类型,给出了发育学解释,推测羽毛起源的时间可能在三叠纪中期,对于羽毛起源和早期演化研究具有重要意义。     

基于标准k-epsilon湍流模型的实验室微环境数值模拟

为了研究实验室微环境的气体污染物浓度分布问题,提出了基于标准k-epsilon湍流模型的数值模拟方法.建立"回"形和"一"形楼道二维简化模型,对其进行网格划分.以浓度为7.73ppm的NO_2作为研究对象,设置不同位置的气体污染物入口,对两种二维模型的风场和NO_2浓度场进行数值模拟和分析.结果表明,"回"形楼道不利于污染物的扩散,各区域都有污染物的分布,浓度最低区域降幅在87.6%~96.7%;"一"形楼道模型中,inlet10、inlet14和inlet19分别作为入口时,B区域NO_2浓度值很低,monitor5-9浓度接近0.模拟结果符合理论,可以为实验室设计选址提供一定参考,也可以为污染气体泄露应急预案和事故预报预警机制提供依据.     

陈列语言中文字说明的意义及特点

随着陈列语言研究的理论化和科学化,其中对于文字说明部分的探索人们也有了越来越深入的认识.文章以山西博物院基本陈列<晋魂>为例,陈列语言中文字说明的意义及特点进行一些探讨.     

Effects of maternal aging on localizations and expression levels of DNA methyltransferases and chromosome architecture in in-vivo matured mouse oocytes

This paper investigated the age-related changes in the expression patterns of maintenance methyltransferase (DNMT1) and de novo methyltransferases (DNMT3a, 3b, 3L) and the chromosome architecture in in-vivo matured mouse oocytes using two-photon laser-scanning microscope. Our results showed that (1) DNMT1 and DNMT3a, 3b, 3L in the oocytes of pubertal mice were located in the cortical region of oocyte cytoplasm. In aging groups, DNMT1 was also located in the cortical region. However, DNMT3a, 3b, 3L had a relatively wider distribution in the oocyte cytoplasm and appeared near the chromosomes. These differences between pubertal and aging groups suggested that aging might affect DNA methylation; (2) the expression of DNMT1, and DNMT3a, 3b in aging groups increased significantly compared to pubertal groups, while, the expression of DNMT3L decreased. These results might be explained by the compensation mechanism among DNMTs, which might be impervious to aging; (3) aging caused increased errors in the distribution and three-dimensional morphology of chromosomes, including the increased total volume and surface area, the high ratio of height to diameter of a circular cylinder enclosing the chromosomes (H/D). Our work provided morphological information for the studies of age-related decline in oocyte qualities.