The increasing dependency of man on machines have led to increase computational load on systems. The increasing computational load can be handled to some extent by scaling up processor frequencies. However, this approach has hit a frequency and power wall and the increasing awareness towards green computing discourages this solution. This leads us to use multi-core architectures. Due to the same reason, real-time systems are also migrating from single-core towards multi-core systems. While multi-core systems provide scalable high computational power, they also expose real-time systems to several challenges. Most of these challenges hamper the key property of real-time systems, i.e., predictability. In this work, we address some challenges imposed by multi-core architectures on real-time systems. We propose and evaluate several scheduling algorithms and demonstrate improved predictability and performance over existing methods. A unifying them in all our algorithms is that we explicitly consider the effects of architectural factors on the scheduling and schedulablity of real-time programs. As a case study, we use Tilera's TilePro64 platform as an example multi-core platform and implement some of our algorithms on this platform. Through this case study, we derive several useful conclusions regarding performance, predictability and practical overheads on a multi-core architecture.

Hybrid error control techniques to improve data communication performance for noisy channels have been extensively studied. However, a growing concern in communication system design is the impact of delay due to retransmissions and/or delay-prone technologies on system performance. Previous analyses have not considered various delay aspects of a hybrid error control system. Efficient error control techniques which are able to provide improved coding gain and throughput by promptly matching the error correction coding capability with the changing channel conditions have yet to be developed and investigated. In this thesis, delay-related performance characteristics are investigated for asynchronous time division multiplexing links. Two different methods based on an imbedded Markov chain model are developed and applied to the system with a noisy feedback channel, yielding analytical expressions for the buffer occupancy and the block delay. A recursive expression for packet loss probability for systems with a finite transmitter buffer is obtained. The concept of delay-limited error control coding is introduced for real-time communications. Performance improvement by truncation of a type-II hybrid-ARQ protocol with one retransmission is investigated in detail. It is shown that the truncated protocol has a bounded delay and bounded queue length under typical communication traffic conditions. The error performance of the truncated protocol is further analyzed for various mobile fading channels. Matched-rate hybrid error control coding for both adaptive and non-adaptive cases is also studied. A new adaptive error control protocol using Reed-Solomon codes is proposed. The protocol uses novel feedback transmissions to achieve faster estimation of channel states. Numerical optimization is carried out by introducing overall throughput and modified throughput as efficiency criteria. Based on channel bit error rate measurement, optimum overall throughput is obtained with minimum implementation complexity. Our general conclusions are: (1) Both delay and packet loss can be greatly reduced by incorporating a Reed-Solomon code into the data-link protocol for noisy channels. (2) The truncated hybrid error control protocol can provide coding gain improvement and reduced delay over the conventional (untruncated) protocol. (3) Throughput efficiency of a type-I or type-II hybrid-ARQ protocol can be significantly improved by using the proposed matched-rate error control techniques. / Graduate

Figural sculpture and 3d real-time visualisation.

This thesis deals with the issues of detecting the codec used for the encoding of voice data carried by the RTP protocol without having access to the information carried by signalisation protocols in VoIP applications. Its main goal is to create and implement a fast algorithm for detecting the codec used for voice transfer via the RTP protocol. This algorithm should be fast enough to be used for offline analysis of captured data as well as for real-time online analysis. For research of possibilities were compared two approaches of detection. Detection by the characteristics of the codecs was chosen to solve the problem itself. Within the solution was performed data analysis and implementation of the application followed by testing on data.

The goal of the thesis is to examine possibilities of dynamic reconfiguration in real-time component systems, especially to formally describe support of operating modes. The thesis introduces a reconfiguration mechanism based on properties and relations between them. The mechanism is designed to facilitate a straight forward modeling of operating modes and reconfiguration rules and preserves re-usability of assembled components. The thesis also presents a realization of the mechanism suitable for the domain of embedded real-time systems.

The e-sport market is a growing one and as it grows monetary interests, willingness to exploit it grows with it. A part of the e-sport market that is not satisfied yet is the market of mobile applications catering to e-sport audiences. To tackle the problem this thesis explores the problems one might encounter whilst developing a soft real-time mobile application for an esport game. The applications name is CScore, an application that will present the score of ongoing e-sports matches. Methods used for data analysis of necessary information includes analytical induction and coding. As system development model a prototyping model was used with Scrum as its framework. This thesis results in the presentation of a prototype of CScore, with enough information about the application to develop the complete system. An overview of the planned CScore system is presented including, how to retrieve information about matches and current information of ongoing matches. The relationship model of the local database and the layout of the mobile application is also presented. / E-sport är en växande marknad och medans den växer har många investerares intressen för denna marknad ökat. En av dessa branscher är mobila applikationer för e-sport fans. Denna rapport visar detaljerat hur man förbereder sig för en ny marknad och hur man utvecklar en real-tids mobilapplikation för ett e-sport spel. Applikationen kallas CScore och är en applikation som presenterar poängen av pågående e-sport matcher. Metoderna använda för data analys av nödvändig information inkluderar analytisk induktion och “coding”. Som systemutvecklingsmodell användes en prototypbaserad modell med Scrum som ramverk. Projektet resulterar i att en prototyp av CScore presenteras, med tillräcklig information om hur denna applikation borde implementeras för att utveckla det fullvärdiga systemet. En översikt över CScore systemet är presenterat inklusive hur information om matcher skall hämtas samt hur information om pågående matcher skall hämtas. Relationsmodellen över databasen och layouten för mobilapplikationen presenteras också.

In this thesis, we explore detailed voxel scene compression methods and editing thereof with the goal to design an interactive voxel viewer/editor, for e.g. a 3D printing appli- cation. We present state-of-the-art GPU compatible data structures and compare them. On top of the chosen data structure, we build standard editing tools known from 2D, capable of changing voxel color in real-time even on lower end machines. 1

The transition from a mathematical algorithm to a physical hardware implementation is non-trivial. This thesis discusses the issues involved in the transition from the theory of real-time trajectory generation all the way through a hardware experiment. Documentation of the validation process as well as modifications to the existing theory as a result of hardware testing are treated at length. The results of hardware experimentation show that trajectory generation can be done in real-time in a manner facilitating coordination of multiple small UAVs.

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