A blockchain-empowered authentication scheme for worm detection in wireless sensor network

Wireless Sensor Network(WSN)is a distributed sensor network composed a large number of nodes with low cost,low performance and self-management.The special structure of WSN brings both convenience and vulnerability.For example,a malicious participant can launch attacks by capturing a physical device.Therefore,node authentication that can resist malicious attacks is very important to network security.Recently,blockchain technology has shown the potential to enhance the security of the Internet of Things(IoT).In this paper,we propose a Blockchain-empowered Authentication Scheme(BAS)for WSN.In our scheme,all nodes are managed by utilizing the identity information stored on the blockchain.Besides,the simulation experiment about worm detection is executed on BAS,and the security is evaluated from detection and infection rate.The experiment results indicate that the proposed scheme can effectively inhibit the spread and infection of worms in the network.

水丝蚓(Tubificid worms)扰动对磷在湖泊沉积物-水界面迁移的影响

为探讨水丝蚓(Tubificid worms)扰动对磷在湖泊沉积物-水界面间迁移的影响,选取太湖梅梁湾与大浦口两富营养化湖区为研究对象,通过室内培养实验,利用Rhizon间隙水采样器等技术,研究了水丝蚓扰动对太湖沉积物-水界面理化性质及溶解活性磷(SRP)在界面通量的影响.结果表明水丝蚓扰动能够增大表层沉积物含水率、氧化还原电位,减小间隙水中Fe2+浓度.水丝蚓没有显著改变梅梁湾间隙水中SRP浓度,同时促进了梅梁湾沉积物中SRP向上覆水的释放;但水丝蚓显著减小了大浦口间隙水中SRP浓度,并抑制了大浦口沉积物中SRP向上覆水的释放.水丝蚓扰动对磷在沉积物-水界面间迁移的不同影响可能是由沉积物中Fe2+含量差异较大造成的.

WORMS评分中滑膜炎症与膝骨性关节炎中医证型的关联性研究

目的:探讨膝骨性关节炎性滑膜炎与膝骨关节炎中医证型的相关性。方法:自2015年1月至2018年6月,选取213例膝骨关节炎的患者,进行中医辨证分型,其MRI影像进行WORMS评分,同时做WORMS评分中滑膜炎和中医证型的相关性分析。结果:213例患者中,风寒湿痹证25例(占11.7%),风湿热痹证84例(占39.4%),瘀血痹阻证43例(占20.2%),肝肾亏虚证61例(占28.6%);在WORMS评分中,滑膜炎评分为0分的12例(占5.6%),1分的60例(占28.2%),2分的50例(占23.5%),3分的91例(占42.7%);相关性分析中,差异有统计学意义,WORMS评分中滑膜炎3分组更容易发生在风湿热痹证中(χ^2=137.286,P=0.000)。结论:膝骨性关节炎滑膜炎患者临床上以风湿热痹型(39.4%,84/213)为主,这对于相关治疗有一定的指导意义。

New Localities and Palaeoscolecid Worms from the Cambrian(Stage 4,Series 2)Guanshan Biota in Kunming,Yunnan,South China

The Guanshan Biota from the Cambrian Stage 4 Wulongqing Formation is a typical Burgess-shale type Lagerst？tte that had witnessed the Cambrian explosion. Here we report two new localities of the Guanshan Biota, which is located at Baimei village, south of Kunming and Xinglong village, Wuding County, Yunnan Province respectively. Both localities produce soft-body fossils and several new taxa, e.g. a new species of palaeoscolecidans （Palaeoscolex xinglongensis sp. nov.） reported herein. The comparative study of the new species with similar form not only indicates that there is a diversification of palaeoscolecid species in Guanshan Biota, but also strengthens the ties between the older Chengjiang Biota and the younger Kaili Biota （and also the coeval Burgess Shale community）. Three paleoecological features, including high diversity, little disparity and richness of palaeoscolecid worms, are summarized as a case study to represent the differences between Guanshan and Chengjiang Biota.

Global dynamics of a novel multi-group model for computer worms

In this paper, we study worm dynamics in computer networks composed of many autonomous systems. A novel multigroup SIQR （susceptible-infected-quarantined-removed） model is proposed for computer worms by explicitly considering anti-virus measures and the network infrastructure. Then, the basic reproduction number of worm R0 is derived and the global dynamics of the model are established. It is shown that if R0 is less than or equal to 1, the disease-free equilibrium is globally asymptotically stable and the worm dies out eventually, whereas, if R0 is greater than 1, one unique endemic equilibrium exists and it is globally asymptotically stable, thus the worm persists in the network. Finally, numerical simulations are given to illustrate the theoretical results.

Instant Messaging Worms Propagation Simulation and Countermeasures

Instant messaging （IM） has become one of the most popular online communication tools among consumer and enterprise IM users. It provides instant message delivery, as well as convenient file transfer services. The increasing popularity and functionalities of IM programs have made it increasingly attractive for attackers, especially for worm writers. IM contact list offers worm an easy way of finding potential victims so that the worm could achieve a surprising spreading speed. This paper first presents our experimental results of simulating IM worm propagation in the logical network defined by IM contact lists, which is reported to be a scale-free network. Then, the existing proposals for detecting and containing IM worm epidemics are discussed. At last, a new algorithm for this purpose is presented, which is based on the observation of the bi-directional nature of IM worm traffic, and its advantages and possible improvements in implementation are analyzed. The simulation results show the proposed algorithm is of significant effect on restricting IM worm propagation.

模拟Worms的游戏设计与实现

本课题的目标是仿照Team17的Worms2D系列游戏产品,开发一款2D游戏,了解整个游戏开发流程,设计一款2D游戏引擎,封装了Direct3D9的部分图形绘制接口、图形控制接口、音效接口,并在此基础上实现一款2D射击游戏.

Simulating Greedy Propagation of P2P Worms

Greedy propagation policy for unstructured P2P worms employs the neighboring node list of each node in peer-to-peer （P2P） network to speed up the propagation of P2P worms. After describing the technique background of P2P worms, the algorithm of greedy propagation is addressed. Simulating design for this novel propagation policy is also described. Then, the effects of the greedy propagation policy on spreading speed, convergence speed, and attacking traffic in static P2P worms are simulated and discussed. The primary experimental results show that the greedy propagation is harmful and can bring severe damages to P2P network.

Modeling and Defending Passive Worms over Unstructured Peer-to-Peer Networks

Passive worms can passively propagate through embedding themselves into some sharing files, which can result in significant damage to unstructured P2P networks. To study the passive worm behaviors, this paper firstly analyzes and obtains the average delay for all peers in the whole transmitting process due to the limitation of network throughput, and then proposes a mathematical model for the propagation of passive worms over the unstructured P2P networks. The model mainly takes the effect of the network throughput into account, and applies a new healthy files dissemination-based defense strategy according to the file popularity which follows the Zipf distribution. The simulation results show that the propagation of passive worms is mainly governed by the number of hops, initially infected files and uninfected files. The larger the number of hops, the more rapidly the passive worms propagate. If the number of the initially infected files is increased by the attackers, the propagation speed of passive worms increases obviously. A larger size of the uninfected file results in a better attack performance. However, the number of files generated by passive worms is not an important factor governing the propagation of passive worms. The effectiveness of healthy files dissemination strategy is verified. This model can provide a guideline in the control of unstructured P2P networks as well as passive worm defense.

Research in Computer Viruses and Worms

Viruses and worms have become so common that most computer users now accept them as a fact of life.This paper introduces the definitions and difference of the computer viruses and worms.Some main research problems about the computer viruses and worms in recent years are also summarized and discussed in detail.Finally the developing trend of the computer virus and worms is proposed.

Research and Development of P2P Worms

With the development and the application of many popular peer-to-peer （P2P） systems such as eMule and BitTorrent, worms probably employ the features of these P2P networks to put them at risk. Some features, such as the local routing table and the application routing mechanism, are helpful to quickly distribute the P2P worms into the networks. This paper aims to give a comprehensive survey of P2P worms. The definition and the classification of P2P worms are discussed firstly. Then, the research and development of P2P worms, including experimental analysis, propagation modeling, and defensive approaches, are addressed and analyzed in detail.

An Immunization Strategy for Social Network Worms Based on Network Vertex Influence

Along with the rapid development of social networks, social network worms have constituted one of the major internet security problems. The root of worm is the inevitable software vulnerability during the design and implementation process of software. So it is hard to completely avoid worms in the existing software engineering systems. Due to lots of bandwidth consumption, the patch cannot be transmitted simultaneously by the network administrator to all hosts. This paper studies how to prevent the propagation of social network worms through the immunization of key nodes. Unlike existing containment models for worm propagation, a novel immunization strategy is proposed based on network vertex influence. The strategy selects the critical vertices in the whole network. Then the immunization is applied on the selected vertices to achieve the maximal effect of worm containment with minimal cost. Different algorithms are implemented to select vertices. Simulation experiments are presented to analyze and evaluate the performance of different algorithms.

Comparison of Two Pour-On Formulations of Ivermectin against Gastrointestinal Worms, Fleas and Lice in Naturally Infected Stray Dogs

The aim of the present study was to evaluate the efficacy of two commercial pour-on ivermectin formulations against intestinal parasites (IP), fleas and lice in naturally infested stray dogs. Eighteen crossbreed dogs with eggs of IP as well as adult fleas and lice were included in the trial. On day 0, the dogs were randomly divided into 3 groups of 6 animals each: a group receiving a single pour-on treatment with 0.5% ivermectin (500 mcg/kg), a group treated similarly with 0.2% iver-mectin (200 mg/kg), and a control group. Fecal and skin analyses were carried out on days 0, 7, 14, 21 and 28 to determine the reduction of eggs and the number of fleas and lice. Weight gain was also measured on day 28. On day 30, the dogs were humanely sacrificed in order to count adult IP. Efficacy was measured as the percentage of the reduction of eggs per gram fecal mass (EPGF), of adult IP, fleas and lice relative to the control group. For the eggs of IP, ivermectin at 0.5% showed an efficacy of 100% against ascarids and 79% against Ancylostoma caninum. ivermectin at 0.2% removed 90.2% of the ascarids and 50.4% of A. caninum. For adult IP, the efficacy of 0.5% iver-mectin against Toxocara canis and A. caninum was 100%, and for 0.2% ivermectin it was 62.4% and 76.4% for T. canis and A. caninum, respectively. Both compounds were 100% effective against lice and 96% and 71.1% efficacious against fleas, respectively. However, neither treatment was effective against Dypilidium caninum. Weight gain in treated dogs was statistically different from that of the controls (p < 0.05). We concluded that 0.5% pour-on ivermectin showed better efficacy than 0.2% pour-on ivermectin in the reduction of eggs and adult intestinal parasites and fleas;it was similarly efficacious against lice.

Research on the Propagation Models and Defense Techniques of Internet Worms

Internet worm is harmful to network security,and it has become a research hotspot in recent years.A thorough survey on the propagation models and defense techniques of Internet worm is made in this paper.We first give its strict definition and discuss the working mechanism.We then analyze and compare some repre-sentative worm propagation models proposed in recent years,such as K-M model,two-factor model,worm-anti-worm model（WAW）,firewall-based model,quarantine-based model and hybrid benign worm-based model,etc.Some typical defense techniques such as virtual honeypot,active worm prevention and agent-oriented worm defense,etc.,are also discussed.The future direction of the worm defense system is pointed out.

基于媒介齿轮的修正型渐开线包络环面蜗杆传动啮合性能分析

环面蜗杆传动因其多齿啮合特性而具有承载能力强等优势,但其约束数相应增加,对制造误差及装配误差更为敏感。为降低重载环面蜗杆传动的误差敏感性,提出了一种修正型渐开线齿轮包络环面蜗杆传动。构建渐开线齿轮与媒介齿轮及环面蜗杆三者之间的啮合几何学模型,建立了传动副空间点接触局部共轭接触分析方法;通过数值分析及有限元仿真分析,揭示了修正型渐开线齿轮包络环面蜗杆传动啮合特性的变化规律。结果表明,该新型环面蜗杆传动具有较低的误差敏感性,同时保持了高载荷下的承载能力。针对某人机交互7000 m自动化钻机重载机器人回转关节,研制了修正型渐开线包络环面蜗杆传动减速器样机,并进行了相关性能试验,验证了理论分析的准确性。

圆柱及环面蜗杆传动副承载能力分析与试验

针对某工程机械的实际运行工况和设计参数要求,建立蜗杆传动副优化设计目标函数及工况约束。设计并优化圆柱蜗杆传动副和环面蜗杆传动副,分析2类蜗杆传动副在工作载荷和静态自锁载荷下的齿面接触特性;研制对应2种类型蜗杆副传动样机,搭建传动副样机性能测试试验台,开展传动副的负荷运转试验并对比考察齿面磨损情况。结果表明:在相同的设计参数、加载方法和加载载荷下,环面蜗杆副相较于圆柱蜗杆副,同时接触齿对较多,齿面等效应力和等效应变较小,齿面磨损较轻,承载能力更高。

科幻小说《玫瑰与蠕虫》的“二元合一”叙事

《玫瑰与蠕虫》是俄罗斯科幻作家罗伯特·伊巴图林获得多项俄罗斯科幻大奖的小说。小说给人杂乱无序、扑朔迷离、生涩难懂之感。之所以如此,经研究发现,小说整体呈现“二元合一”的叙事模式:小说的叙事空间呈现“异托邦”与“恶托邦”合一;叙事线索呈现明、暗交叉合一;叙事内容呈现二元对立合一;叙事风格呈现科幻与悬疑合一。这种叙事模式最终指向:在当今人工智能和网络科技飞速发展之下,对人类未来会面临的生存危机进行反思和预警。

19世纪轴测投影发展的建筑应用:以舒瓦西“仰视轴测图”为例

轴测投影在19世纪的欧洲实现了理论上的长足发展,舒瓦西作为将其应用于建筑表现的代表性人物,以其极具特色的“仰视轴测图”对部分建筑结构理论的形成起到了重要的指导作用。因而,本文将梳理19世纪轴测投影发展的历程,并具体讨论舒瓦西轴测图的特点、成因与发展变化,以浅析其图示对当世及后世建筑历史研究与建筑设计表达的影响。

供丝机烟丝束线性堆叠原理分析与应用

为了进一步降低ZJ112卷接机组的卷烟产品空头剔除率,通过对几种主要卷烟机型供丝装置结构、供料及成形工艺原理的研究分析,并结合废烟剔除情况,分析揭示的原理为烟丝在供丝机内从料仓到流化床的平行推进输送原理;烟丝从流化床到吸风室导轨的线性堆叠成形原理。发现了供丝机内在烟丝输送方面与空头形成相关的两个因素,设计应用的改进方案为设计安装新型螺旋绞龙底部凹口护板与延板组件;延长料仓内吸风管的长度,合理设置吸风管口在吸风腔内的位置。改进后,基本消除了回丝被重复性削刷而增加造碎劣化的问题,改善了成品烟支内的烟丝结构质量,降低了产品空头剔除率,提升了吸丝成形工艺过程控制水平。