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.

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。

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.

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.

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.

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.

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.

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.

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.

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.

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.

New insights on serodiagnosis of trichinellosis during window period:early diagnostic antigens from Trichinella spiralis intestinal worms

The clinical diagnosis of trichinellosis is difficult because its clinical manifestations are nonspecific.Detection of anti-Trichinella IgG by ELISA using T.spiralis muscle larval excretory-secretory(ES)antigens is the most commonly used serological method for diagnosis of trichinellosis,but the main disadvantage is false negativity during the early stage of infection.There is an obvious window period between Trichinella infection and antibody positivity.During the intestinal stage of Trichinella infection,the ES antigens of intestinal worms(intestinal infective larvae and adults)are exposed to host’s immune system at the earliest time and elicit the production of specific anti-Trichinella antibodies.Anti-Trichinella IgG antibodies in infected mice were detectable by ELISA with ES antigens of intestinal worms as soon as 8-10 days post infection(dpi),but ELISA with muscle larval ES antigens did not permit detection of infected mice before 12 dpi.Therefore,the new early antigens from T.spiralis intestinal worms should be screened,identified and characterized for early serodiagnosis of trichinellosis.

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.

Worms Live Longer and Have Fun,Too

长命,是自古以来人们的一种渴望。现在看来,人类在延续人的寿命方面的努力已经闪烁成功的曙光。本文告诉我们,科学家在虫子身上的试验,已经获得成功。就现在的科研成果而言,具有实践意义的内容是:Experiments haveshown that lifetime low-calorie diets,for instance,can help mice live longer thannormal.另一条却是无法实现的:…reproduction somehow shortens lifespanand that animals whose reproductive systems are shut down may live longer.

Immunization of mice with cells from juvenile worms of Schistosoma japonicum provides immunoprotection against schistosomiasis

To validate the protective efficacy against schistosomiasis by immunization with cells from juvenile Schistosoma japonicum in a murine model; to analyze possible factors related to protection, in this study, two independent repeated vaccination trials were performed. After three subcutaneous vaccinations, in trial one, in the absence of adjuvant, primary juvenile worm cells (pJCs) from S. japonicum induced remarkable average reductions in worm burden (54.3%), liver eggs per gram (LEPG) load (59.8%) as well as egg granulomas size (66.5%) compared to PBS control group (P【0.01), which were significantly higher than those elicited by fractions of juvenile worm cells (JCFs) or fractions of juvenile worms (JWFs) (P【0.05). Non-cell components of worms (WNCs) showed no significant protection. In trial two, compared to PBS control group, significant protective effect was also observed for cultured juvenile worm cells (cJCs) from S. japonicum with 58.4% worm reduction; 68.1% LEPG reduction (P【0.01). However, cultured adult worms cells (cACs) showed significantly higher worm burden (P【0.05); egg burden (P【0.01) when compared to cJCs. Immunological analysis of trial two revealed that cJCs engendered a Th1-biased mixed Th1/Th2 type of immune response while cACs elicited a Th2-type response. Our data indicated that immunization with both primary; cultured cells from S. japonicum juvenile worms provided high immunoprotection, for which the physical character of immunogens, stage-specific parasite; the type of immune response induced might be responsible, suggesting that vaccination with whole cells from S. japonicum larvae is a promising approach to produce protective immunity against schistosomiasis.

Modeling and analyzing of the interaction between worms and antiworms during network worm propagation

Interaction of antiworms with a worm population of e.g. hosts of worm infected and hosts of antiworm infected must be considered as a dynamic process. This study is an attempt for the first time to understand how introduction of antiworm affects the dynamic of network worm propagation. In this paper, we create a mathematical model (SIAR model) using ordinary differential equations to describe the interaction of worms and antiworms. Although idealized, the model demonstrates how the combination of a few proposed nonlinear interaction rules between antiworms and worms is able to generate a considerable variety of different kinds of responses. Taking the Blaster and Nachi worms as an example, we give a brief analysis for designing a practical antiworm system. To the best of our knowledge, there is no model for the spread of an antiworm that employs the passive scan and the finite lifetime and we believe that this is the first attempt on understanding the interaction between worms and antiworms.

Fast Multicast on Multistage Interconnection Networks Using Multi-Head Worms

This paper proposes a new approach for implementing fast multicast on multistage interconnection networks (MINs) with multi-head worms. For an MIN with n stages of k×k switches, a single multi-head worm can cover an arbitrary set of destinations with a single communication start-up. Compared with schemes using unicast messages, this approach reduces multicast latency significantly and performs better than multi-destination worms.

A Far-Out Case of Ascariasis Causing Small Bowel Obstruction in Mauritius

Ascaris lumbricoides (A. lumbricoides), the soil-transmitted helminth is the most prevalent parasitic infection of the gastrointestinal tract in developing countries. Heavy worm loads mainly due to untreated worm infestations are often associated with increased risk of severe sequelae. We report the first complicated case of A. lumbricoides causing small bowel obstruction in a 9-year-old boy that necessitated surgical intervention on a tropical island in the Indian Ocean, where cases of Ascariasis are rarely encountered.

膝关节骨关节炎全关节磁共振成像评分观察者间一致性评价

目的探讨应用全关节磁共振成像评分(WORMS)系统对膝关节各结构特征进行半定量评价的观察者间一致性以及观察者临床阅片经验对评分结果的影响。方法利用“祛风止痛胶囊对膝骨关节炎的临床作用及机制研究”临床研究项目数据库,随机抽取2018年5至10月摄取的膝关节骨关节炎患者的磁共振像(MRI)10例,分别由3位年资不同、拥有不同临床阅片经验并接受过膝关节WORMS评分系统培训的放射科医生应用WORMS评分对患者患膝MRI进行评价。以其中1位高年资并具备MRI定量及半定量评估认证资质阅片医生的评分结果为参考值,将另2位阅片医生的评分结果分别与参考值比较并计算kappa值。采用SPSS 22.0软件对数据进行统计学处理。P<0.05为结果有统计学意义。结果另2位阅片医生评分与参考值之间全部征象均kappa值≥0.6,其中软骨下骨髓水肿、软骨下囊肿、骨磨损和关节内游离体的WORMS评分在3位观察者之间具有很高的一致性(kappa值≥0.75)。与低年资阅片医生相比,高年资阅片医生与参考值之间的观察者间一致性无明显提高。结论经过标准化培训后,拥有不同临床阅片经验的放射科医生均可掌握膝关节骨关节炎WORMS评分方法,而临床阅片经验对评分效果无显著影响。