Semantics for probabilistic programming, Dr Chris Heunen

Semantics for probabilistic programming, Dr Chris Heunen

03.10.17, 1pm, Room JCB 1.33B

Abstract: Statistical models in e.g. machine learning are traditionally
expressed in some sort of flow charts. Writing sophisticated models
succintly is much easier in a fully fledged programming language. The
programmer can then rely on generic inference algorithms instead of
having to craft one for each model. Several such higher-order functional
probabilistic programming languages exist, but their semantics, and
hence correctness, are not clear. The problem is that the standard
semantics of probability theory, given by measurable spaces, does not
support function types. I will describe how to get around this.

Seminar: Propagation and Reification: SAT and SMT in Prolog (continued)

Jacob Howe, City University, London

Abstract: This talk will recap how a watched literal DPLL based SAT solver can be succinctly coded in 20 lines of Prolog. The focus of the talk will be the extension of this solver to an SMT solver which will be discussed with a particular focus on the case where the theory is that of rational-tree constraints, and its application in a reverse engineering problem.
[Note change of time from that previously advertised]

Event details

  • When: 23rd June 2017 13:00 - 14:00
  • Where: Cole 1.33a
  • Series: AI Seminar Series
  • Format: Seminar

SRG Seminar: Evaluation Techniques for Detection Model Performance in Anomaly Network Intrusion Detection System by Amjad Al Tobi

Everyday advancements in technology brings with it novel challenges and threats. Such advancement imposes greater risks than ever on systems and services, including individual privacy information. Relying on intrusion specialists to come up with new signatures to detect different types of new attacks, does not seem to scale with excessive traffic growth. Therefore, anomaly-based detection provides a promising solution for this problem area.

Anomaly-based IDS applies machine learning, data mining and/or artificial intelligence along with many other methods to solve this problem. Currently, these solutions seem not to be tractable for real production environments due to the high false alarms rate. This might be a result of such systems not being able to determine the point at which an update is required. It is not clear how detection models will behave over time, when traffic behaviour has changed since the last time the model was re-generated.
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Event details

  • When: 1st June 2017 13:00 - 14:00
  • Where: Cole 1.33b
  • Series: Systems Seminars Series
  • Format: Seminar

SRG Seminar: New Network Functionality using ILNPv6 and DNS by Khawar Shehzad

This research deals with the introduction of a new network functionality based on Identifier-Locator Network Protocol version 6 (ILNPv6), and Domain Name System (DNS). The chosen area of concern is security and specifically mitigation of Distributed Denial of Service (DDoS). The functionality proposed and tested deals with the issues of vulnerability testing, probing, and scanning which directly lead to a successful DDoS attack. The solutions presented can be used as a reactive measure to these security issues. The DDoS is chosen because in recent years DDoS have become the most common and hard to defend attacks. These attacks are on the availability of system/site. There are multiple solutions in the literature but no one solution is based on ILNPv6, and are complex in nature. Similarly, the solutions in literature either require modification in the providers’ networks or they are complex if they are only site-based solutions. Most of these solutions are based on IPv6 protocol and they do not use the concept of naming, as proposed by ILNPv6.

The prime objectives of this research are:

  • to defend against DDoS attacks with the use of naming and DNS
  • to increase the attacker’s effort, reduce vulnerability testing, and random probing by attackers
  • to practically demonstrate the effectiveness of the ILNPv6-based solution for security

Event details

  • When: 18th May 2017 13:00 - 14:00
  • Where: Cole 1.33b
  • Series: Systems Seminars Series
  • Format: Seminar

SRG Seminar: Investigation of Virtual Network Isolation Security in Cloud Computing Using Penetration Testing by Haifa Al Nasseri

Software Defined Networking (SDN) or Virtual Networks (VNs) are required for cloud tenants to leverage demands. However, multi-tenancy can be compromised without proper isolation. Much research has been conducted into VN Isolation; many researchers are not tackling security aspects or checking if their isolation evaluation is complete. Therefore, data leakage is a major security concern in the cloud in general.

This research uses an OpenStack VN and OpenStack Tenant Network to test multi-tenancy features. We are evaluating the relationship between isolation methods used in cloud VN and the amount of data being leaked through using penetration tests. These tests will be used to identify the vulnerabilities causing cloud VN data leakage and to investigate how the vulnerabilities, and the leaked data, can compromise the tenant Virtual Networks.

Event details

  • When: 4th May 2017 13:00 - 14:00
  • Where: Cole 1.33b
  • Series: Systems Seminars Series
  • Format: Talk

SRG Seminar: “Evaluating Data Linkage: Creation and use of synthetic data for comprehensive linkage evaluation” by Tom Dalton and “Container orchestration” by Uchechukwu Awada

The abstract of Tom’s talk:

“Data linkage approaches are often evaluated with small or few data sets. If a linkage approach is to be used widely, quantifying its performance with varying data sets would be beneficial. In addition, given a data set needs to be linked, the true links are by definition unknown. The success of a linkage approach is thus difficult to comprehensively evaluate.

This talk focuses on the use of many synthetic data sets for the evaluation of linkage quality achieved by automatic linkage algorithms in the domain of population reconstruction. It presents an evaluation approach which considers linkage quality when characteristics of the population are varied. We envisage a sequence of experiments where a set of populations are generated to consider how linkage quality varies across different populations: with the same characteristics, with differing characteristics, and with differing types and levels of corruption. The performance of an approach at scale is also considered.

The approach to generate synthetic populations with varying characteristics on demand will also be addressed. The use of synthetic populations has the advantage that all the true links are known, thus allowing evaluation as if with real-world ‘gold-standard’ linked data sets.

Given the large number of data sets evaluated against we also give consideration as to how to present these findings. The ability to assess variations in linkage quality across many data sets will assist in the development of new linkage approaches and identifying areas where existing linkage approaches may be more widely applied.”

The abstract of Awada’s talk:

“Over the years, there has been rapid development in the area of software development. A recent innovation in software or application deployment and execution is the use of Containers. Containers provide a lightweight, isolated and well-defined execution environment. Application container like Docker, wrap up a piece of software in a complete file-system that contain everything it needs to run: code, runtime, system tools, system libraries, etc. To support and simplify large-scale deployment, cloud computing providers (i.e., AWS, Google, Microsoft, etc) have recently introduced Container Service Platforms (CSPs), which support automated and flexible orchestration of containerised applications on container-instances (virtual machines).

Existing CSP frameworks do not offer any form of intelligent resource scheduling: applications are usually scheduled individually, rather than taking a holistic view of all registered applications and available resources in the cloud. This can result in increased execution times for applications, and resource wastage through under utilised container-instances; but also a reduction in the number of applications that can be deployed, given the available resources. In addition, current CSP frameworks do not currently support: the deployment and scaling of containers across multiple regions at the same time; merging containers into a multi-container unit in order to achieve higher cluster utilisation and reduced execution times.

Our research aims to extend the existing system by adding a cloud-based Container Management Service (CMS) framework that offers increased deployment density, scalability and resource efficiency. CMS provides additional functionalities for orchestrating containerised applications by joint optimisation of sets of containerised applications and resource pool in multiple (geographical distributed) cloud regions. We evaluate CMS on a cloud-based CSPs i.e., Amazon EC2 Container Management Service (ECS) and conducted extensive experiments using sets of CPU and Memory intensive containerised applications against the custom deployment strategy of Amazon ECS. The results show that CMS achieves up to 25% higher cluster utilisation and up to 70% reduction in execution times.”

Event details

  • When: 20th April 2017 13:00 - 14:00
  • Where: Cole 1.33b
  • Series: Systems Seminars Series
  • Format: Seminar

Distinguished Lecture Series 2017: Dr David Manlove

On March 31st, Dr David Manlove from the University of Glasgow, delivered the semester two distinguished lectures in Lower and Upper College Hall. The overall title was algorithms for healthcare-related matching problems.

David started with an overview of complexity theory and solving hard problems. He gave examples of this in practice, for example how researchers constructed a best-possible tour around the best 20,000 pubs in the UK. The second lecture focussed on how to assign junior doctors to hospitals in the best way, a very practical problem but with interesting complexity issues. The final lecture focussed on the life-changing topic of how to set up exchanges of kidneys between healthy donors and patients needing transplants. David talked about how his expertise in algorithms has been translated into regularly finding the best possible matches which then result in real transplants taking place.

David is pictured above at various stages of the distinguished lecture series and outside College Hall with Head of School, Prof Steve Linton, Prof Ian Gent and Dr Ishbel Duncan,

Videos from the DLS can be accessed on Vimeo –
Lecture 1: https://vimeo.com/211633740
Lecture 2: https://vimeo.com/211634119
Lecture 3: https://vimeo.com/211634923

Images courtesy of Ryo Yanagida.

Seeing the Wood for the Trees – Essential Structure in Model-based Search by Prof. John McCall

Problem structure, or linkage, refers to the interaction between variables in a black-box fitness function. Discovering structure is a feature of a range of search algorithms that use structural models at each iteration to determine the trajectory of the search. Examples include Information Geometry Optimisation (IGO), Covariance Matrix Adaptation Evolution Strategy (CMA-ES), Bayesian Evolutionary Learning (BEL) and Estimation of Distribution Algorithms (EDA).

In particular, EDAs use probabilistic graphical models to represent structure learned from evaluated solutions. Various EDA approaches using trees, directed acyclic graphs and undirected graphs have been developed and evaluated on a range of benchmarks with a variety of representations.
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Event details

  • When: 4th April 2017 14:00 - 15:00
  • Where: Cole 1.33
  • Series: School Seminar Series
  • Format: Seminar

SRG Seminar: nMANET, the Name-based Data Network (NDN) for Mobile Ad-hoc Networks (MANETs) by Percy Perez Aruni

The aim of this talk is to introduce the nMANET, the Name-based Data Network (NDN) for Mobile Ad-hoc Networks (MANETs) approach. nMANET is an alternative perspective on utilising the characteristics of NDN to solve the limitations of MANETs, such as mobility and energy consumption. NDN, which is an instance of Information Centric Networking (ICN), provides an alternative architecture for the future Internet. In contrast with traditional TCP/IP networks, NDN enables content addressing instead of host based communication. NDN secures the content instead of securing the communication channel between hosts, therefore the content can be obtained from the intermediate caches or final producers. Although NDN has proven to be an effective design in wired networks, it does not perfectly address challenges arising in MANETs. This shortcoming is due to the high mobilty of mobile devices and their inherent resource constraints, such as remaining energy in batteries.

The implementation of nMANET, the Java based NDN Forwarder Daemon (JNFD), aims to fill this gap and provide a Mobile Name-based Ad-hoc Network prototype compatible with NDN implementations. JNFD was designed for Android mobile devices and offers a set of energy efficient forwarding strategies to distribute content in a dynamic topology where consumers, producers and forwarders have high mobility and may join or leave the network at unpredictable times. nMANET evalues JNFD through benchmarking to estimate efficiency, which is defined as high rates of reliability, throughput and responsiveness with a low energy consumption.

Event details

  • When: 6th April 2017 13:00 - 14:00
  • Where: Cole 1.33b
  • Series: Systems Seminars Series
  • Format: Seminar

DLS: Algorithms for healthcare-related matching problems

Algorithms for healthcare-related matching problems

Distinguished Lecture Series, Semester 2, 2016-7

David Manlove

School of Computing Science, University of Glasgow

Lower College Hall (with overflow simulcast in Upper College Hall)

Abstract:

Algorithms arise in numerous everyday appPicture of David Manlovelications – in this series of lectures I will describe how algorithms can be used to solve matching problems having applications in healthcare settings.  I will begin by outlining how algorithms can be designed to cope with computationally hard problems.  I will then describe algorithms developed at the University of Glasgow that have been used by the NHS to solve two particular matching problems.  These problems correspond to the annual assignment of junior doctors to Scottish hospitals, and finding “kidney exchanges” between kidney patients and their incompatible donors in the UK.
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Event details

  • When: 31st March 2017 09:15 - 15:30
  • Where: Lower College Hall
  • Series: Distinguished Lectures Series
  • Format: Distinguished lecture