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Examensarbeten och uppsatser / Final Theses

Framläggningar på IDA / Presentations at IDA

Se även framläggningar annonserade hos ISY och ITN i Norrköping / See also presentations announced at ISY and ITN in Norrköping (in Swedish)

If nothing is stated about the presentation language then the presentation is in Swedish.

WExUpp - kommande framläggningar
2018-09-18 - SaS
HTTP Based Adaptive Bitrate Streaming Protocols in Live Surveillance Systems
Daniel Dzabic, Jacob Mårtensson
Grundnivå (16hp)
kl 13:15, Alan Turing (In English)
This thesis explores possible solutions to replace Adobe Flash Player by using tools already built into modern web browsers, and explores the tradeoffs between bitrate, quality, and delay when using an adaptive bitrate for live streamed video. Using an adaptive bitrate for streamed video was found to reduce stalls in playback for the client by adapting to the available bandwidth. A newer codec can further compress the video file size while maintaining the same video quality. This can improve the viewing experience for clients on a restricted or a congested network. The tests conducted in this thesis show that producing an adaptive bitrate stream and changing codecs is a very CPU intensive process.
2018-09-26 - SaS
Efficient Multi-Core Implementation of the IPsec Encapsulating Security Payload Protocol for a Single Security Association
Mattias Hellsing, Albin Odervall
Avancerad (30hp)
kl 13:15, Alan Turing (In English)
As the mobile Internet traffic increases, the workload of the base stations processing this traffic increases with it. To cope with this, the telecommunication providers responsible for the systems deployed in these base stations have looked to parallelism. This, together with the fact that these providers have a vested interest in protecting their users' data from potential attackers, means that there is a need for efficient parallel packet processing software which handles encryption as well as authentication. A well known protocol for encryption and authentication of IP packets is the Encapsulating Security Payload (ESP) protocol of the IPsec protocol suite. IPsec establishes simplex connections, called Security Associations (SA), between entities that wish to communicate. This thesis investigates a special case of this problem where the work of encrypting and authenticating the packets within a single SA is parallelized. This problem was investigated by developing and comparing two multi-threaded implementations based on the Eventdev and ring buffer libraries of Data Plane Development Kit (DPDK). One additional Eventdev-based implementation was also investigated which schedules linked lists of packets, instead of single packets, in an attempt to reduce the overhead of scheduling packets to the worker cores. These implementations were then evaluated in terms of throughput, latency, speedup, and last level cache miss rates. The results showed that the ring buffer-based implementation performed the best in all metrics while the single packet-scheduling Eventdev-based implementation was outperformed by the one using linked lists of packets. It was shown that the packet generation, which was done by the receiving core, was the main limiting factor for all implementations. In addition, the memory resources such as the memory bus, memory controller and prefetching hardware were shown to likely be an area of contention and a possible bottleneck as the packet generation rate increases. The conclusion drawn from this was that a parallelized packet retrieval solution such as Receive Side Scaling (RSS) together with minimizing memory resource contention is necessary to further improve performance.
2018-09-28 - SaS
Permissioned blockchains and distributed databases: a performance study
Sara Bergman
Avancerad (30hp)
kl 15:15, Alan Turing (In English)
Blockchain technology is a booming new field in both computer science and economics
and other use cases than cryptocurrencies are on the rise. Permissioned blockchains are one
instance of the blockchain technique. In a permissioned blockchain the nodes which validates
new transactions are trusted. Permissioned blockchains and distributed databases
are essentially two different ways for storing data, but how do they compare in terms of
performance? This thesis compares Hyperledger Fabric to Apache Cassandra in four experiments
to investigate their insert and read latency. The experiments are executed using
Docker on an Azure virtual machine and the studied systems consist of up to 20 logical
nodes. Latency measurements are performed using varying network size and load. For
small networks, the insert latency of Cassandra is twice as high as that of Fabric, whereas
for larger networks Fabric has almost twice as high insert latencies as Cassandra. Fabric
has around 40 ms latency for reading data and Cassandra between 150 ms to 250 ms, Fabric
scales better for reading. The insert latency of different workloads is heavily affected by the
configuration of Fabric and by the Docker overhead for Cassandra. The read latency is not
affected by different workloads for either system.
2018-10-05 - SaS
: Parallelization of Aggregated FMUs using Static Scheduling
Mattias Hammar
Avancerad (30hp)
kl 09:00, Donald Knuth (In English)
This thesis implements and evaluates static scheduling for aggregated FMUs. An aggregate FMU is several coupled FMUs placed in a single FMU. The implementation creates task graphs from the internal dependencies and connections between the coupled FMUs. These task graphs are then scheduled using two different list scheduling heuristics, MCP and HLFET. The resulting schedules are then executed in parallel by using OpenMP in the
runtime. The implementation is evaluated by looking at the utilization of the schedule, the execution time of the scheduling and the speedup of the simulation. These measurements are taken on three different test models. With model exchange FMUs only a really small speedup is observed. With co-simulation models the speedup varies a lot depending on the model, the highest achieved speedup was 2.8 running on four cores
2018-10-05 - SaS
Why is security stll an issue? – A study comparing developer’s sofware security awareness to existing vulnerabilites in software applicatons
Lars Backman
Grundnivå (16hp)
kl 13:00, Alan Turing (In English)
The need for secure web applications grows ever stronger with more and more sensitive, personal data, making its’ way to the Internet. During the last decade, hackers have stolen enormous amounts of data from high profile companies and social institutions. In this paper, we try to answer the questions of why these things occur; Why do programmers write vulnerable code? To answer this question, we conducted a case study on a smaller software development company. By performing penetration tests, surveys and interviews we successfully identified several weaknesses in their product and their way of working, that could lead to security breaches in their application.
We also conducted a security awareness assessment and found multiple contributing factors to why these weaknesses occur. Insufficient knowledge, misplaced trust, and lousy testing policies are some of the reasons to why these vulnerabilities appeared in the studied CRM-system.

Page responsible: Ola Leifler
Last updated: 2017-04-27