高可靠实时分布处理系统的结点机结构研究和实现

本文对几种高可靠结点机的硬件体系结构从可靠性、实时性、可实现性等方面进行了分析比较。通过对多计算机组成的结点机结构的详细分析 ,可以看出容错算法并行实现技术、智能表决技术、实现上的标准化、模块化技术可以使实现的结点机在满足高可靠的同时满足实时性要求 。

Research of NS dataflow mechanism and its analyzer implementation

This paper analyzes the main elements in NS network simulator, makes adetailed view of dataflow management in a link, a node, and an agent, respectively, and introducesthe information described by its trace file. Based on the analysis of transportation and treatmentof different packets in NS, a dataflow state machine is proposed with its states exchange triggeringevents and a dataflow analyzer is designed and implemented according to it. As the machine statefunctions, the analyzer can make statistic of total transportation flux of a specified dataflow andoffer a general fluctuation diagram. Finally, a concrete example is used to test its performance.

Architecture Singularity Analysis of 4-U■S/U■U 5-DOF Parallel Mechanism

Architecture singularity of a parallel mechanism with five degrees of freedom (DOF) is analyzed. Such mechanism consists of a movable platform connected to the base by five active limbs. Four of them are identical 6-DOF limbs and the last one has the same DOF as the specified DOF of the movable platform. Based on the kinematics analysis, two categories of architecture singularities for such mechanism are proposed. Then the sufficient condition for each singularity is researched. Results show that the mechanism is singular when it employs each category of the proposed architecture, provided that it satisfies the corresponding sufficient condition. It can be concluded that the proposed two categories of architecture singularities should be avoided with the following dimensional synthesis of such mechanism.

Belt or network?The spatial structure and shaping mechanism of the Great Wall cultural belt in Beijing

The relationship between cross-regional cultural landscapes does not currently receive enough attention in cultural landscape conservation. Cultural landscapes in China are faced with the crisis of fragmentation and islanding, which makes it necessary to strengthen the idea of integrated conservation. The Great Wall cultural belt in Beijing is a cross-regional linear cultural landscape in the northwest mountainous area of Beijing. With the Great Wall as a link connecting the surrounding natural, social, and cultural resources to form a banded structure, it has the typical and practical significance of integrated conservation. Based on the theory of the cultural landscape security pattern and its ‘node – setting – connection' model, this research studies the spatial structure and shaping mechanism of the Great Wall cultural belt in Beijing from the perspective of tourist flow, using Flickr geo-tagged photos and Wikiloc tracks. The results identify the core nodes and intermediate nodes of the Great Wall cultural belt in Beijing and show that it has a multicore, multi-group hierarchical nesting structure differing from the geographic space, which has groups following the evolution orbit of ‘linear string – circumnuclear star – complete network.' To explain the differences between the cultural association network(CAN) and the geospatial network(GSN), we find that the cultural associations between nodes rely on geophysical channels, including heritage corridors and traffic passages, as physical carriers, but the nodes' attraction and their setting elements, containing natural geography environments, settlements, administrative divisions, etc., change the channel resistance, so CAN and GSN present different characteristics. From the perspective of systematic and spatial network thoughts, this study has made an attempt to adopt new analysis and research methods to achieve the integrated conservation and inheritance of linear cultural landscapes in mountainous areas.

Calculation of Steady SF_6 Gas Flow through a 420 kV Circuit Breaker Nozzle and Electric Field Distribution

Special interest in current interruptions is dedicated to the processes close to the current zero instant, the so-called interaction region, which determines the circuit breakers＇ performance. The quantities of interest in this region are the distribution of temperature, density and pressure, velocity and gas mass flow along the electric arc axis, as well as the distribution of electric stress between contacts Calculation of steady SF_6 gas flow through the nozzle of a 420 kV circuit breaker at the current zero instant, for different arcing durations, was carried out using a commercial CFD （computational fluid dynamics） simulation tool. The calculation results were used to get insight into improvement possibilities of the SF_6 gas flow model used in the software for computer simulation of HV （high-voltage） circuit breakers. Electric field calculation results were performed for the same 420 kV circuit breaker, in order to estimate the breakdown voltage at the current zero instant.

海量并行计算机系统的发展

近二十年来,尽管通用计算机的处理速度平均每五年提高一个数量级,但是对于一个串行体系结构的计算机而言,其速度最终将受到信号传输和器件延时的限制。因此,为了从本质上提高计算机的处理速度,必须采用多机并行处理技术,这是计算机体系结构的发展趋势,它突破串行执行的冯诺依曼体系结构,从而使计算速度得到极大地提高。随着微处理器和半导体存贮器性能的提高和成本的下降。

CLIP: viewing the RNA world from an RNA-protein interactome perspective

The pervasive transcription of the genome creates many types of non-coding RNAs(nc RNAs).However,we know very little regarding the functions and the regulatory mechanisms of these nc RNAs.Exploring the interactions of RNA and RNA binding proteins(RBPs) is vital because it can allow us to truly understand how these nc RNAs behave in vivo.High-throughput sequencing of RNA isolated by cross-linking immunoprecipitation(HITS-CLIP or CLIP-seq) and its variants have been successfully used as systemic techniques to study RBP binding sites.In this review,we will explain the major differences between the CLIP techniques,summarize successful applications of these techniques,discuss limitations of CLIP,present some suggested solutions and project their promising future roles in studying the RNA world.

Advanced 3D nanohybrid foam based on graphene oxide: Facile fabrication strategy, interfacial synergetic mechanism, and excellent photocatalytic performance

Herein,a unique nanohybrid foam was fabricated with titanium dioxide(TiO2)-carbon quantum dots(CQDs)nanoparticles intercalated between graphene oxide(GO)layers via a facile and low-cost solvothermal method.Compared with pure GO foam,the fabricated GO-TiO2-CQDs foam displayed high degradation rate towards methyl orange(MO),methylene blue(MB),and rhodamine B(Rh B),respectively,under the Xenon lamp irradiation.The composite foam can be used for several times and remain a high degradation rate without structural damage.The photochemical property was attributed to the 3D porous structure of GOTiO2-CQDs foam,in which ultrafine hydrogenated TiO2-CQDs nanoparticles were densely anchored on the GO sheets.This paper provides an efficient strategy to tune the charge transport and thus enhance the photocatalytic performance by combining the semi-conductive GO and quantum dots.