Our discovery of the Star Wars bots on Twitter is reported by New Scientist

January 12th, 2017 No comments

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Army of 350,000 Star Wars bots found lurking on Twitter

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“Computer scientists at University College London recently felt a disturbance in the force. They discovered a Twitter botnet – which they think could comprise more than 350,000 accounts – that has tweeted thousands of random quotations from Star Wars novels….”

The full story is available online at  New Scientist

The research paper is available at  arXiv.org/abs/1701.02405v1

Other media reports @SZ_UCL





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Our new paper in IEEE CloudNet’15

September 7th, 2015 Comments off



I am pleased to report that my PhD student Sebastian Jeuk and I have a full-length paper accepted by the IEEE CloudNet’15. This conference is a world leading venue in the research area of cloud computing and is jointly sponsored by the IEEE Communications Society and the IEEE Cloud Computing Society. This is a research work in collaboration with our partners at Cisco’s research HQ in California, US.

Title: Network Segmentation in the Cloud — A Novel Architecture Based on UCC and IID

Authors: Sebastian Jeuk, Gonzalo Salgueiro, Fred Baker and Shi Zhou

Conference: The 4th IEEE International Conference on Cloud Networking (CloudNet’15) 

Abstract: Cloud Computing is known for its scalability, flexibility and on-demand workload creation. Today, cloud-enabled data centers utilize VLAN, VxLAN or GRE segmentations but these techniques, despite being widely deployed, have a variety of inherent technical and architectural limitations. In this paper we introduce a novel architecture leveraging UCC and IID for segmentation, rather than those traditionally used today (e.g., VLAN, VxLAN, etc.). The proposed architecture is entirely based on IPv6 and, for illustrative purposes only, is demonstrated using OpenStack as the cloud framework. This proposed reference architecture is based entirely on UCC and IID, two OpenStack-independent concepts, which could easily be realized in outer cloud frameworks as well. UCC introduces cloud-specific traffic isolation within IPv6 extension headers. IIDs can be incorporated as a unique identifier within an IPv6 address to identify endpoints. The combination of both allows network devices to segregate traffic according to cloud service, cloud tenants and endpoint affiliation. Here, we highlight current shortcomings of existing segmentation techniques as well as define design considerations for the cloud framework in question (i.e. in this case OpenStack) to circumvent such limitations. The proposed architecture is depicted and explained in the context of a traffic flow example.


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Shi Zhou’s promotion to a Senior Lecturer

September 7th, 2015 No comments



Dr. Shi ZHOU is promoted to a Senior Lecturer with effect from 1 October 2015.

Senior Lecturer is an academic rank in the UK, which is equivalent to a Tenured Associate Professor in the North America (with responsibility of supervising PhD students).


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Our new paper in PLOS ONE on epidemic modelling of the computer worm Conficker

May 21st, 2015 No comments




Hybrid Epidemics — A Case Study on Computer Worm Conficker

Authors: Changwang Zhang, Shi Zhou, Benjamin M. Chain

PLOS ONE 10(5):e0127478

DOI: 10.1371/journal.pone.0127478

Published: May 15, 2015

Conficker is a computer worm that erupted on the Internet in 2008. It is unique in combining three different spreading strategies: local probing, neighbourhood probing, and global probing. We propose a mathematical model that combines three modes of spreading: local, neighbourhood, and global, to capture the worm’s spreading behaviour. The parameters of the model are inferred directly from network data obtained during the first day of the Conficker epidemic. The model is then used to explore the tradeoff between spreading modes in determining the worm’s effectiveness. Our results show that the Conficker epidemic is an example of a critically hybrid epidemic, in which the different modes of spreading in isolation do not lead to successful epidemics. Such hybrid spreading strategies may be used beneficially to provide the most effective strategies for promulgating information across a large population. When used maliciously, however, they can present a dangerous challenge to current internet security protocols.
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New office and new phone number

May 13th, 2015 No comments


I have moved into my new office: Room 308, at 66-72 Gower Street (map).

My new office phone number is  020 3108 7088 (UCL internal: 57088).

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Paper in IEEE/ACM CCGrid 2015 on Universal Cloud Classification (UCC)

May 13th, 2015 No comments

15th IEEE/ACM International Symposium on Cluster, Cloud and Grid Computing

Shenzhen Skyline


 Title: A Novel Approach To Classify Cloud Entities: Universal Cloud Classification (UCC)

Authors: Sebastian Jeuk, Gonzalo Salgueiro and Shi Zhou.

Abstract: One of the fundamental requirements of Cloud Computing is the capability to provide scalable, transparent and isolated networks. This is achieved by using L2 segmentation via 802.1Q VLANs or overlay approaches such as 802.1ad, VxLAN, ”Stateless Transport Tunneling” (STT) or ”Network Virtualization using Generic Routing Encapsulation” (NVGRE). All of these technologies struggle to provide the required level of scalability, flexibility, performance and network isolation within a Data Center. Research efforts in the area of classification have fundamentally approached these challenges by introducing identifiers for segmentation or providing overlay solutions to tunnel traffic. However, these research approaches are too specific without tackling the actual Cloud Computing classification challenges. Here, we investigate classification approaches with the goal of introducing a scalable, optional, hierarchical, end-to-end and transparent Layer 3 provider, service and tenant isolation scheme. This proposal addresses major challenges and limitations of current cloud classification schemes by offering these five advantages: (1) hierarchical endto- end classification, (2) transparency to upper-layer protocols, (3) optional for en-route and endpoint evaluation, (4) flexibility, and (5) improved performance over current overlay technologies. The solution proposal will be implemented and evaluated based on its feasibility, functionality, performance and usability in cloud-related use-cases.

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Paper in Scientific Reports on Critically Hybrid Epidemics

May 13th, 2015 No comments

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Optimizing Hybrid Spreading in Metapopulations

Changwang Zhang, Shi Zhou, Joel C. Miller, Ingemar J. Cox & Benjamin M. Chain

Published 29 April 2015



Epidemic spreading phenomena are ubiquitous in nature and society. Examples include the spreading of diseases, information, and computer viruses. Epidemics can spread by local spreading, where infected nodes can only infect a limited set of direct target nodes and global spreading, where an infected node can infect every other node. In reality, many epidemics spread using a hybrid mixture of both types of spreading. In this study we develop a theoretical framework for studying hybrid epidemics, and examine the optimum balance between spreading mechanisms in terms of achieving the maximum outbreak size. We show the existence of critically hybrid epidemics where neither spreading mechanism alone can cause a noticeable spread but a combination of the two spreading mechanisms would produce an enormous outbreak. Our results provide new strategies for maximising beneficial epidemics and estimating the worst outcome of damaging hybrid epidemics.

Categories: Epidemic spreading, My Research Tags:

Paper in PLOS Computational Biology on HIV infection modelling

May 13th, 2015 No comments


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Title: Hybrid Spreading Mechanisms and T Cell Activation Shape the Dynamics of HIV-1 Infection

Changwang Zhang, Shi Zhou, Elisabetta Groppelli, Pierre Pellegrino, Ian Williams, Persephone Borrow, Benjamin M. Chain , Clare Jolly

Published: April 2, 2015

DOI: 10.1371/journal.pcbi.1004179


Author Summary

The ability to spread using more than once mechanism, named hybrid spreading, is a ubiquitous feature of many real world epidemics including HIV and Hepatitis C virus infection in vivo, and computer worms spreading on the Internet. Hybrid spreading of HIV is well documented experimentally but its importance to HIV progression has been unclear. In this paper, we introduce a mathematical model of HIV dynamics that explicitly incorporates hybrid spreading. The model output shows excellent agreement to two sets of clinical data from a treatment naive cohort and from the Short Pulse Anti-Retroviral Therapy at Seroconversion trial. The model demonstrates that hybrid spreading is an essential feature of HIV progression, a result which has significant implications for future therapeutic strategies against HIV.

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My PhD student Changwang ZHANG has passed his viva.

May 13th, 2015 No comments


Congratulations to my PhD student Changwang ZHANG, who successfully defended his PhD thesis last week.

His thesis title is: Hybrid epidemic spreading – from Internet worms to HIV infection. This multi-disciplinary research has produced some very exciting results,  some of which have been widely reported in the media.

Guardian: HIV spreads like computer worms, say scientists, http://www.theguardian.com/society/2015/apr/02/hiv-spreads-like-computer-worms-say-scientists.

Daily Mail: HIV spreads like a computer worm: Researchers find virus mimics an online infection – and warn early detection is key, http://www.dailymail.co.uk/sciencetech/article-3023671/HIV-spreads-like-computer-virus-Researchers-spread-mimics-online-infection-warn-early-detection-key.html

Times of India: HIV spreads like ‘computer worms’, http://timesofindia.indiatimes.com/life-style/health-fitness/health-news/HIV-spreads-like-computer-worms/articleshow/46803875.cms

Science Daily: HIV spreads like internet malware and should be treated earlier,http://www.sciencedaily.com/releases/2015/04/150402161747.htm

Medical Daily: HIV, Like Internet Malware, Spreads Through The Body Using A Two-Pronged Method Of Attack,http://www.medicaldaily.com/hiv-internet-malware-spreads-through-body-using-two-pronged-method-attack-328282

International Business Times UK: HIV: Early treatment crucial as virus uses double entry mode, http://www.ibtimes.co.uk/hiv-early-treatment-crucial-virus-uses-double-entry-mode-1494842

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Paper in IEEE CloudCom 2014

October 10th, 2014 No comments


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Our paper will be presented at IEEE CloudCom 2014.

Title: Universal Cloud Classification (UCC) and its evaluation in a data center environment

Authors: Sebastian Jeuk, Gonzalo Salgueiro, Shi Zhou

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