OUrsi stands for "Open University Research Seminar Informatica". The
OUrsi is the research seminar of the Department of Computer Science of the Open
University of the Netherlands. OUrsi talks typically take place on the
last Tuesday of the month at 11:00 in Heerlen, and are normally streamed
online for the benefit of interested parties elsewhere. The OUrsi
features presentations on ongoing research in all areas of Computer
Science.
If you are interested in giving a presentation, or attending one
(live in Heerlen or online), please contact Hugo Jonker. Below are listed the scheduled
presentations, with the upcoming OUrsi
highlighted .
No. |
Date |
Presenter |
Title |
|
|
TITLE
NAME
ABSTRACT
|
33. |
16 October |
Johan
Jeuring |
TBA |
|
|
TITLE
Johan Jeuring, OU & University of Utrecht
ABSTRACT
|
32. |
25 September |
Josje Lodder |
Developing an e-learning tool for inductive proofs |
abstract
|
|
Developing an e-learning tool for inductive proofs
Josje Lodder
Proving is a central subject of most logic course. Students attending
such courses do not only have to learn how to prove consequences in a
formal system, but they also have to reason about formal systems. A
typical example of an exercise that occurs in many textbooks is the
following: prove that the number of left parentheses in a logical
formula is equal to the number of right parentheses. These kinds of
properties can be proved by structural induction, where the structure
of the proof follows the structure of the inductive definition of the
logical language.
Students have conceptual as well as technical problems with inductive
proofs. In this talk I will discuss our ideas and first results
concerning the development of an e-learning tool that helps students
to practice with inductive proofs.
|
31. |
26 June |
Hugo Jonker |
Investigating Adblock wars |
abstract
|
|
Investigating Adblock wars
Hugo Jonker
We investigate the extent to which websites react to filter list
updates. We collected data on the Alexa Top-10K for 120 days, and on
specific sites newly added to filter lists
for 140 days. By evaluating how long a filter rule triggers on a
website, we can gauge how long it remains effective. We matched
websites with both regular adblocking filter lists (Easylist) and with
filter lists that remove anti-adblocking (primarily UblockProtector /
NanoProtector). From our data, we observe that the effectiveness of
the Easylist adblocking filter decays initially, but after ~80 days
seems to stabilize. However, we found no evidence for any significant
decay in effectiveness of the more specialized, but less widely used,
Ublock Protector / Nano Protector list.
|
30. |
24 April |
Stijn de Gouw |
Human-in-the-Loop Simulation of Cloud Services |
abstract,
slides
|
|
Human-in-the-Loop Simulation of Cloud Services
Stijn de Gouw
We present an integrated tool-suite for the simulation of software
services which are offered on the Cloud. The tool -suite uses the
Abstract Behavioral Specification (ABS) language for modeling the
software services and their Cloud deployment. For the real-time
execution of the ABS models we use a Haskell backend which is based
on a source-to-source translation of ABS into Haskell. The tool-suite
then allows Cloud engineers to interact in real-time with the
execution of the model by deploying and managing service instances.
The resulting human-in-the-loop simulation of Cloud services can be
used both for training purposes and for the (semi-)automated support
for the real-time monitoring and management of the actual service
instances.
|
29. |
27 March |
Benjamin Krumnow |
The Shepherd Project: Automated security audits of website login
processes |
abstract,
slides
|
|
The Shepherd Project: Automated security audits of web
login processes
Benjamin Krumnow
HTTP does not have memory. HTTP Cookies were created to address this.
These cookies thus allow web sites to remember things, such as whether you
are logged in or not. After logging in, the cookies authenticate the
user, so that the user does not have to type his password with every
click. If an attacker steals these cookies, he could thus impersonate a user.
In 2010, the Firesheep plugin for Firefox demonstrated how easy it was
to steal such cookies for many popular web sites (Gmail, Facebook,
etc.). The problem that Firesheep exploited was that cookies were sent
over an insecure channel (HTTP instead of HTTPS). Such an attack is
called a session hijacking attack.
In the Shepherd project, we investigate the adoption of countermeasures
against session hijacking attacks. Over the last year, we have
developed an automatic selenium-based scanner. This scanner performs
an automated audit of the security of login processes of web
sites.
In this OUrsi talk, I will give you an overview of the current
scanning framework, explain how it assesses login security
and talk about our current study, where we analyse over 65K
websites. I hope that we will have lively discussion to identify
possible unclear points and future directions.
|
28. |
27 February |
Vincent van der
Meer |
Future-proofing recovery of deleted files |
abstract,
slides
|
|
To maintain the ability to recover deleted files: about the
further development and future-proofing of this digital forensic
specialization
Vincent van der Meer
Reconstructing deleted files, file carving, is a crucial part of
digital forensic work, often concerning child pornography. The
explosive growth of data makes file carving increasingly
time-consuming and therefore increasingly inadequate, so that evidence
remains hidden. File carving is still set up separately per device and
per app, resulting in a considerable delay to develop file carving for
new apps. This research will investigate how the app-specific part can
be made as small as possible by abstraction and generalization.
Spin-off will be a widely applicable, modular, maintainable and
expandable framework with corresponding benchmark to compare the
results of new technologies.
|
27. |
19 February |
Hassan Alizadeh |
Intrusion Detection and Traffic Classification using
Application-aware Traffic Profiles |
abstract,
slides
|
|
Intrusion Detection and Traffic Classification using Application-aware Traffic Profiles
Hassan Alizadeh
Along with the growing number of applications and end-users, online
network attacks and advanced generations of malware have continuously
proliferated. Many studies have addressed the issue of intrusion
detection by inspecting aggregated network traffic with no knowledge
of the responsible applications/services. Such systems fail to detect
intrusions in applications whenever their abnormal traffic fits into
the network normality profiles. This research addresses the problem of
detecting intrusions in (known) applications when their traffic
exhibits anomalies. To do so, a network monitoring tool needs to: (1)
identify the source application responsible for the traffic; (2) have
per-application traffic profiles; and (3) detect deviations from
profiles given a set of traffic samples. This work is mainly devoted
to the last two topics. Upon an initial survey on traffic
classification techniques, this research proposes the use of three
different kinds of Gaussian Mixture Model (GMM) learning approaches,
namely classic, an unsupervised and Universal Background Model (UBM)
to build per-application profiles. The effectiveness of the proposed
approaches has been demonstrated by conducting different sets of
experiments on two public datasets collected from real networks, where
the source of each traffic flow is provided. Experimental results
indicate that while the proposed approaches are effective for most
applications, the UBM approach significantly outperforms other
approaches.
|
26. |
19 February |
Fenia Aivaloglou |
How Kids Code and How We Know |
abstract,
slides
|
|
How Kids Code and How We Know
Fenia Aivaloglou
Programming education is nowadays beginning from as early as
the elementary school age. Block-based programming languages like
Scratch are increasingly popular, and there is substantial research
showing that they are suitable for early programming education.
However, how do children program, and are they really learning? In
this talk we will focus on Scratch and explore the programs that
children write. By scraping the Scratch public repository we have
download and analyzed 250K projects in terms of complexity, used
abstractions and programming concepts, and code smells. We will
further discuss the effect of code smells to novice Scratch
programmers and our experiments in Dutch classrooms. Focusing on how
to teach good programming practices to children, we designed the edx
MOOC "Scratch: Programmeren voor kinderen" and we analyzed the results
of its first run, where more that 2K children actively participated.
We found factors that can predict successful course completion, as
well as age-related differences in the students' learning
performance. To further examine the children's motivation and
self-efficacy and their relation to learning performance we run a
Scratch course in three schools and we will present our initial
findings.
|
25. |
30 January 2018 |
Greg Alpár |
Blockchain for identity management, seriously? |
abstract
|
|
Blockchain for identity management, seriously?
Greg Alpár
Right now (Dec. 11, 2017, 15:45) 1 Bitcoin is €14228.71. This
amazing success of a cryptocurrency has made the blockchain
technology, underlying that of Bitcoin, so exciting for businesses
that it is often called the next big revolution after the internet.
Blockchains are proposed to solve all kinds of problems in our digital
world. Besides the financial context, identity is considered to be
another promising area for blockchains. Is it a good idea?
In this OUrsi session, I would like to share with you some thoughts
with regard to the application of blockchains in identity management.
Since there is no big results in our study yet, this talk will
hopefully turn into a fruitful discussion.
|
|
24. |
30 November |
Pekka Aho |
Automated Model Extraction and Testing of Graphical User Interface
Applications |
abstract,
slides
|
|
Automated Model Extraction and Testing of Graphical User
Interface Applications
Pekka Aho
The industry practice for test automation through graphical user
interface is script-based. In some tools the scripts can be recorded
from the user (capture & replay tools) and in others, the scripts are
written manually. The main challenge with script-based test automation
is the maintenance effort required when the GUI changes. One attempt
to reduce the maintenance effort has been model-based testing that
aims to generate test cases from manually created models. When the
system under testing (SUT) changes, changing the models and
re-generating the test cases is supposed to reduce the maintenance
effort. However, creating the formal models allowing test case
generation requires very specialized expertise. Random testing (monkey
testing) is a maintenance-free and scriptless approach to automate GUI
testing. In random GUI testing, the tool emulates an end-user by
randomly interacting with the GUI under testing by pressing buttons
and menus and providing input to other types of GUI widgets. More
recent research aims to automatically extract the GUI models by
runtime analysis while automatically exploring and interacting with
the GUI (or during random testing). Test case generation based on
extracted models is problematic but by comparing extracted GUI models
of consequent versions it is possible to detect changes on the GUI.
This approach aims to address the maintenance problem with scriptless
regression testing and change analysis.
|
23. |
30 November |
Twan van Laarhoven |
Local network community detection: K-means clustering and
conductance |
abstract,
slides
|
|
Local network community detection: K-means clustering and
conductance
Twan van Laarhoven
Joint work Elena Marchiori
Local network community detection is the task of finding a single
community of nodes in a graph, concentrated around few given seed
nodes. The aim is to perform this search in a localized way, without
having to look at the entire graph. Conductance is a popular objective
function used in many algorithms for local community detection.
In this talk I will introduce a continuous relaxation of conductance.
I will show that continuous optimization of this objective still leads
to discrete communities. I investigate the relation of conductance
with weighted kernel k-means for a single community, which leads to
the introduction of a new objective function, σ-conductance.
Conductance is obtained by setting σ to 0. I will present two
algorithms for optimizing σ-conductance, which show promising
results on benchmark datasets.
|
22. |
27 June |
Jeroen Keiren |
An O(m log n) algorithm for stuttering equivalence |
abstract,
slides
|
|
An O(m log n) algorithm for stuttering equivalence
Jeroen Keiren
In this presentation, I will discuss a new algorithm to determine
stuttering equivalence with time complexity O(m log n), where n
is the number of states and m is the number of transitions of a Kripke
structure. Theoretically, this algorithm substantially improves upon
existing algorithms, which all have time complexity of the order
O(mn) at best. Moreover, when compared with other algorithms,
the new algorithm has better or equal space complexity. Practical
results confirm these findings: they show that the algorithm can
outperform existing algorithms by several orders of magnitude,
especially when the Kripke structures are large.
|
21. |
13 June |
Stef Joosten |
Software development in relation algebra with Ampersand |
abstract,
slides
|
|
Software development in relation algebra with Ampersand
Stef Joosten
Relation algebra can be used as a programming language for building
information systems. We will demonstrate this principle by discussing
a database-application for legal reasoning. In this case study, we
will focus on the mechanisms of programming in relation algebra.
Besides being declarative, relation algebra comes with attractive
promises for developing big software. The case study was compiled with
Ampersand, a compiler whose design and development is the focus of a
research collaboration between Ordina and the Open University.
|
20. |
9 May, 13.30 - 14.30 |
Hieke Keuning |
Code Quality Issues in Student Programs |
abstract,
slides
|
|
Code Quality Issues in Student Programs
Hieke Keuning
Abstract:
Because low quality code can cause serious problems in software
systems, students learning to program should pay attention to code
quality early. Although many studies have investigated mistakes that
students make during programming, we do not know much about the
quality of their code. We have examined the presence of quality
issues related to program-flow, choice of programming constructs
and functions, clarity of expressions, decomposition and
modularization in a large set of student Java programs. We
investigated which issues occur most frequently, if students are able
to solve these issues over time and if the use of code analysis tools
has an effect on issue occurrence. We found that students hardly fix
issues, in particular issues related to modularization, and that the
use of tooling does not have much effect on the occurrence of issues.
|
19. |
4 April |
Greg Alpár |
The Alphabet of ABCs |
abstract,
slides
|
|
The Alphabet of ABCs
Greg Alpár
The digital world becomes more and more a part of the physical world.
Data, bound to our identity, relationships and communications, is
processed all around the world. This may result in privacy harms,
including unwanted advertising, data creep, exclusion, insecurity,
etc. Although much of this data could possibly be used without linking
personally to you, currently everybody seems to accept that we have to
give up on the control over our privacy.
A fundamental technological paradigm today is that you almost have to
identify yourself in order to use a given digital service. What if we
could avoid the need for this? For instance, you could just prove that
you have a train ticket without a central party storing an account
about you and about all your trips. Or you could merely show that you
are over 18 of age without having to show (and let save) your name and
credential number, so you are eligible to buy a bottle of 'jenever'.
Or you could do online shopping with giving away as little personal
information as you used to in a department store in the 70s.
Attribute-based credentials (ABCs) provide a wide variety of possible
scenarios, in which you can prove that you are entitled to do things
that otherwise you can only do by having to use identifiers. In the
last OUrsi meeting Fabian presented the IRMA technology, one of the
most important practical ABC projects, and its applications. In this
OUrsi meeting, I will talk about the neat cryptographic and mathematic
techniques that allow for the above-mentioned high level of
flexibility and practical privacy. (Don't get scared, you won't need
lots of background in mathematics to understand my presentation!)
|
18. |
7 March |
Rolando Trujillo
(University of Luxembourg) |
Counteracting active attacks in social network graphs |
abstract,
slides
|
|
Counteracting active attacks in social network graphs
Rolando Trujillo
Active privacy attacks in social networks attempt to de-anonymize a
social graph by using social links previously established between the
attackers and their victims. Malicious users are hard to identify a
priori, so active attacks are typically prevented by anonymizing
(perturbing) the social graph prior publication. This talk is an
introduction to this type of privacy attack and the anonymization
techniques that have been proposed to counteract it. Towards the end
of the talk we will discuss drawbacks of current approaches and possible
improvements.
|
17. |
7 February 2017 |
Fabian van den Broek |
IRMA, as simple as ABC |
abstract,
slides
|
|
IRMA, as simple as ABC
Fabian van den Broek
I will present the IRMA technology. IRMA (I Reveal My Attributes) is
an attribute-based credential system in which users can obtain
credentials stating attributes about themselves (e.g.\ I'm an employee
of the Open University, with employee-number 1234). These attributes
can be disclosed selectively to verifiers (e.g. I'm an employee of the
Open University, xxxxxxxxxxxxxxxxxxxxx), offering a very flexible and
potentially privacy-friendly way of authentication. This presentation
will mostly focus on the progress we made in the last two years and
the progress we are hoping to achieve in the coming years.
|
|
16. |
25 October |
Jeroen Keiren |
Game-based approach to branching bisimulation |
abstract,
slides
|
|
Game-based approach to branching bisimulation
Jeroen Keiren
Branching bisimilarity and branching bisimilarity with explicit
divergences are typically used in process algebras with silent steps
when relating implementations to specifications. When an
implementation fails to conform to its specification, i.e., when both
are not related by branching bisimilarity (with explicit divergence),
pinpointing the root causes can be challenging. In this paper, we
provide characterisations of branching bisimilarity (with explicit
divergence) as games between Spoiler and Duplicator, offering an
operational understanding of both relations. Moreover, we show how
such games can be used to assist in diagnosing non-conformance
between implementation and specification.
|
15. |
4 October |
Arjen Hommersom |
Flexible Probabilistic Logic for Solving the Problem of
Multimorbidity |
abstract,
slides
|
|
Flexible Probabilistic Logic for Solving the Problem of
Multimorbidity
Arjen Hommersom
One of the central questions in artificial intelligence is how to
combine knowledge representation principles with machine learning
methods. Effectively dealing with structure and relations in data
opens up a wealth of applications in areas such as economics, biology,
and healthcare. In this talk I will discuss a recent project proposal,
which aims to develop a new methodology that provides powerful methods
for deriving knowledge from structured data using state-of-the-art
probabilistic logics. These methods will be applied to deal with a
highly significant and challenging problem in modern medicine:
managing patients with multimorbidity, i.e., patients that have
multiple chronic conditions. The main purpose of this talk is to
obtain feedback as this project will likely soon be presented to an
evaluation committee in the exact sciences.
|
14. |
28 June |
Hugo Jonker |
Gaming the H-index |
abstract |
|
Gaming the H-index
Hugo Jonker
In this talk, we discuss some early results looking into formally
modelling the scientific process, and elucidating what attacks can be
performed on bibliographic metrics. Specifically, we distinguish
between hacking, fraud, and gaming, provide initial notions of these
three terms and initial results towards identifying which gaming
attacks are possible on the H-index.
|
13. |
31 May |
Josje Lodder |
Strategies for axiomatic Hilbert-style proofs |
abstract,
slides
|
|
Strategies for axiomatic Hilbert-style proofs
Josje Lodder
Een van de onderwerpen die studenten tegenkomen bij een logicacursus
is een afleidingssysteem zoals natuurlijke deductie of axiomatisch
afleiden. Het vinden van afleidingen is niet altijd eenvoudig.
Studenten moeten hier veel mee oefenen, en een e-learning systeem kan
hier bij helpen. Voor natuurlijke deductie bestaan er verschillende
ondersteunende tools, maar voor axiomatisch afleiden zijn er geen
tools die studenten helpen bij het maken van deze afleidingen. Om
gerichte feedback en feedforward te kunnen geven hebben we
strategieën ontwikkeld waarmee we automatisch axiomatische bewijzen
kunnen genereren, en we gaan deze strategieën ook gebruiken om
uitwerkingen van studenten te volgen, zodat we op elk moment gericht
feedback kunnen geven.
|
12. |
26 April |
Bastiaan Heeren |
Ask-Elle: an Adaptable Programming Tutor for Haskell Giving Automated
Feedback |
abstract, slides |
|
Ask-Elle: an Adaptable Programming Tutor for Haskell Giving
Automated Feedback
Bastiaan Heeren
Ask-Elle is a tutor for learning the higher-order,
strongly-typed functional programming language Haskell. It
supports the stepwise development of Haskell programs by
verifying the correctness of incomplete programs, and by
providing hints. Programming exercises are added to Ask-Elle by
providing a task description for the exercise, one or more model
solutions, and properties that a solution should satisfy. The
properties and model solutions can be annotated with feedback
messages, and the amount of flexibility that is allowed in
student solutions can be adjusted. The main contribution of our
work is the design of a tutor that combines (1) the incremental
development of different solutions in various forms to a
programming exercise with (2) automated feedback and (3)
teacher-specified programming exercises, solutions, and
properties. The main functionality is obtained by means of
strategy-based model tracing and property-based testing. We have
tested the feasibility of our approach in several experiments,
in which we analyse both intermediate and final student
solutions to programming exercises, amongst others.
|
11. |
29 March |
Hugo Jonker |
MitM attacks evolved |
abstract, slides |
|
MitM attacks evolved
Hugo Jonker
The security community seems to be thoroughly familiar with
man-in-the-middle attacks. However, the common perception of
this type of attack is outdated. It originates from when network
connections were fixed, not mobile, before 24/7 connectivity
became ubiquitous. The common perception of this attack stems
from an era before the vulnerability of the protocol's context
was realised. Thanks to revelations by Snowden and by currently
available man-in-the-middle tools focused on protocol meta-data
(such as so-called `Stingrays' for cellphones), this view is no
longer tenable. Security protocols that only protect the
contents of their messages are insufficient. Contemporary security
protocols must also take steps to protect their context: who is
talking to whom, where is the sender located, etc. In short: the
attacker has evolved. It's high time for our security models and
requirements to catch up.
|
10. |
26 February
13.45-14.30,
Utrecht |
Tanja Vos
|
TESTAR: Automated Testing at the User Interface Level |
abstract, slides |
|
TESTAR: Automated Testing at the User Interface Level
Tanja Vos
Testing applications at the User Interface level is an important
yet expensive and labour-intensive activity. Several tools exist
to automate UI level testing. These tools are based on capture
replay or visual imagine recognition. We present TESTAR, a tool
for automated GUI testing that takes a totally different
approach and has demonstrated to be highly useful in practice.
Using TESTAR, you can start testing immediately and you do not
need to specify test cases in advance. TESTAR automatically
generates and executes random test sequences based on a
structure that is automatically derived from the UI through the
accessibility API. Defects that can be found this way are
crashes or suspicious outputs. For defects related to
functionality, expected outputs need to be added to the tool.
This can be done incrementally. The structure on which testing
is based is build automatically during testing, the UI is not
assumed to be fixed and tests will run even though the UI
evolves, which will reduce the maintenance problem that
threatens the approaches mentioned earlier.
|
9. |
23 February |
Freek Verbeek |
Cross-layer invariants for Network-on-Chips |
abstract, slides |
|
Cross-layer invariants for Network-on-Chips
Freek Verbeek
One of the major challenges in the design and verification of manycore
systems is cache coherency. In bus-based architectures, this is a
well-studied problem. When replacing the bus by a communication
network, however, new problems arise. Cross-layer deadlocks can occur
even when the protocol and the network are both deadlock-free when
considered in isolation. To counter this problem, we propose a
methodology for deriving cross-layer invariants for Network-on-Chips.
These invariants relate the state of the protocols run by the cores to
the state of the communication network. We show how they can be used
to prove the absence of cross-layer deadlocks. Our approach is
generally applicable and shows promising scalability.
|
8. |
26 January 2016 |
Harald Vranken |
About a recently submitted research proposal
|
|
|
|
7. |
27 October |
Bernard van Gastel
|
Inschatten van energieverbruik van software door middel van een
typesysteem
|
abstract, slides |
|
Inschatten van energieverbruik van software door middel van
een typesysteem
Bernard van Gastel
Energieverbruik speelt een steeds bepalendere rol binnen ICT. In
veel toepassingsgebieden is het belangrijk om het
energieverbruik te voorspellen, en ervoor te kunnen
optimaliseren. Deze methoden moeten praktisch zijn: zowel snel
feedback geven als voor grote programma/bibliotheken toepasbaar
zijn. Omdat het energieverbruik sterkt afhangt van de hardware
die gebruikt wordt, moet de gebruikte hardware snel in te
stellen zijn en te wisselen zijn. In dit kader stellen wij een
type systeem voor dat statisch gebruikt kan worden om energie
verbruik compositioneel af te leiden. Dit type systeem werkt op
een kleine theoretische programmeertaal waarbij hardware
interacties expliciet gemaakt zijn.
|
6. |
29 September
10.00-11.00, Eindhoven |
Sung-Shik Jongmans
|
Protocol Programming with Automata: (Why and) How? |
abstract, slides
|
|
Protocol Programming with Automata: (Why and) How?
Sung-Shik Jongmans
With the advent of multicore processors, exploiting concurrency
has become essential in writing scalable programs on commodity
hardware. One important aspect of exploiting concurrency is
programming protocols. In this talk, I explain my recent work on
programming protocols based on a theory of automata.
|
5. |
25 August |
Sylvia Stuurman
|
Setup for a experiment on teaching refactoring |
slides
|
|
|
4. |
30 June |
Jeroen Keiren |
State Space Explosion: Facing the Challenge |
abstract, slides |
|
State Space Explosion: Facing the Challenge
Jeroen Keiren
When processes run in parallel, the total number of states in a system
grows exponentially; this is typically referred to as the state space
explosion problem. The holy grail in model checking is finding a way in
which we can effectively cope with this state space explosion. In this
talk I discuss a line of research in which we use an equational fixed
point logic and parity games as a basis for verification. I will focus
on the latter, and discuss ideas that can be used to reduce these parity
games. For those wondering whether this general theory has any
applications at all I discuss industrial applications of this
technology. If you want to know what these applications are, come listen
to my talk!
|
3. |
26 May |
Arjen Hommersom |
Probabilistic Models for Understanding Health Care Data |
abstract, slides
|
|
Probabilistic Models for Understanding Health Care Data
Arjen Hommersom
In the first part of this talk, I will give an overview of my recent
research in using probabilistic models for health care applications.
In the second part, I will zoom into recent results from the NWO
CAREFUL
project, where we attempt to reconcile probabilistic automata learning
with Bayesian network modelling. In particular, the aim is to identify
the probabilistic structure of states within a probabilistic
automaton. We propose a new expectation-maximisation algorithm that
exploits the state-based structure of these models. This
model is currently being applied to learn models from psychiatry data
to provide novel insights into the treatment of psychotic depressions.
Preliminary results will be discussed.
|
2. |
28 April |
Hugo Jonker |
FP-Block: usable web privacy by controlling browser fingerprinting |
abstract, slides |
|
FP-Block: usable web privacy by controlling browser
fingerprinting
Hugo Jonker
Online tracking of users is used for benign goals, such as detecting
fraudulous logins, but also to invade user privacy. We posit that for
non-oppressed users, tracking within one website does not have a
substantial negative impact on privacy, while it enables
legitimate benefits. In contrast, cross-domain tracking
negatively impacts user privacy, while being of little benefit
to the user.
Existing methods to counter tracking treat any and all tracking
similar: client-side storage is blocked, or all sites are fed
random characteristics to hamper re-identification. We develop a
tool, FP-Block, that counters cross-domain tracking,
while allowing intra-domain tracking. For each visited site,
FP-Block generates a unique, consistent fingerprint: a
"web identity". This web identity is then used for any
interaction with that site, including for third-party embedded
content. This ensures that ubiquitously embedded parties will
see different, unrelatable fingerprints from different sites,
and can thus no longer track the user across the web.
|
1. |
March 31 2015 |
Christoph Bockisch |
A design method for modular energy-aware software |
abstract, slides |
|
A design method for modular energy-aware software
Christoph Bockish
Nowadays achieving green software by
reducing the overall energy consumption of the system is becoming more
and more important. A well-known solution is to make the software
energy-aware by extending its functionality with energy optimizers,
which monitor the energy consumption of software and adapt it
accordingly. Modular design of energy-aware software is necessary to
make the extensions manageable and to cope with the complexity of the
software. To this aim, we propose a model of the energy utilization --
or more general resource utilization -- and an accompanying design
method for components in energy-intensive systems. Optimizer
components can analyze such Resource Utilization Models (RUM) of other
components in terms of such a model and adapt their behavior
accordingly. We show how compact RUMs can be extracted from existing
implementations. Using the Counterexample-Guided Abstraction
Refinement (CEGAR) approach, along with model-checking tools, abstract
models can be generated that help establish key properties relating to
energy consumption. This approach is illustrated by the concrete
example of a network manager sub-system.
|