Curracurrong: a stream processing system for distributed environments

Advances in technology have given rise to applications that are deployed on wireless sensor networks (WSNs), the cloud, and the Internet of things. There are many emerging applications, some of which include sensor-based monitoring, web traffic processing, and network monitoring. These applications collect large amount of data as an unbounded sequence of events and process them to generate a new sequences of events. Such applications need an adequate programming model that can process large amount of data with minimal latency; for this purpose, stream programming, among other paradigms, is ideal. However, stream programming needs to be adapted to meet the challenges inherent in running it in distributed environments. These challenges include the need for modern domain specific language (DSL), the placement of computations in the network to minimise energy costs, and timeliness in real-time applications. To overcome these challenges we developed a stream programming model that achieves easy-to-use programming interface, energy-efficient actor placement, and timeliness. This thesis presents Curracurrong, a stream data processing system for distributed environments. In Curracurrong, a query is represented as a stream graph of stream operators and communication channels. Curracurrong provides an extensible stream operator library and adapts to a wide range of applications. It uses an energy-efficient placement algorithm that optimises communication and computation. We extend the placement problem to support dynamically changing networks, and develop a dynamic program with polynomially bounded runtime to solve the placement problem. In many stream-based applications, real-time data processing is essential. We propose an approach that measures time delays in stream query processing; this model measures the total computational time from input to output of a query, i.e., end-to-end delay

Software analysis methods for resource-sensitive systems

Contains fulltext : 143154.pdf (publisher's version ) (Open Access)Practically every modern electronic device is controlled by software. It is important to establish certain quality characteristics of this software. In his dissertation, Rody Kersten presents innovative analysis methods towards this end. These semi-automatic methods go beyond the validation of input-output behaviour and concerns mostly non-functional properties. The focus is on properties that are of specific importance for embedded systems, such as wireless sensor nodes. For instance, energy-efficiency and security are studied. Embedded systems often have only a limited amount of energy, memory and time available. Methods have been developed that can bound consumption of these resources. During an internship at the NASA Langley Research Center, Kersten developed a method that guarantees high coverage of tested code by a generated test-set. All developed automatic analysis methods are implemented in open-source toolsRadboud Universiteit Nijmegen, 1 september 2015Promotor : Eekelen, M.C.J.D. van Co-promotor : Smetsers, S.V, 120 p

Ranking Functions for Loops with Disjunctive Exit-Conditions

Contains fulltext : 92254.pdf (publisher's version ) (Open Access)2th International Workshop on Foundational and Practical Aspects of Resource Analysis (FOPARA2011). Madrid, Spai

Symbolic Complexity Analysis using Context-preserving Histories

Item does not contain fulltextICST 2017: 10th IEEE International Conference on Software Testing, Verification and Validation, 13-17 March 2017, Tokyo, Japa

Software en energiegebruik

Item does not contain fulltextScientific publicatio

No effect of calcifediol supplementation on skeletal muscle transcriptome in vitamin D deficient frail older adults

Vitamin D deficiency is common among older adults and has been linked to muscle weakness. Vitamin D supplementation has been proposed as a strategy to improve muscle function in older adults. The aim of this study was to investigate the effect of calcifediol (25-hydroxycholecalciferol) on whole genome gene expression in skeletal muscle of vitamin D deficient frail older adults. A double-blind placebo controlled trial was conducted in vitamin D deficient frail older adults (aged above 65), characterized by blood 25-hydroxycholecalciferol concentrations between 20 and 50 nmol/L. Subjects were randomized across the placebo group (n=12) and the calcifediol group (n=10, 10 µg per day). Muscle biopsies were obtained before and after six months of calcifediol or placebo supplementation and subjected to whole genome gene expression profiling using Affymetrix HuGene 2.1ST arrays. Expression of the vitamin D receptor gene was virtually undetectable in human skeletal muscle biopsies. Calcifediol supplementation led to a significant increase in blood 25-hydroxycholecalciferol levels compared to the placebo group. No difference between treatment groups was observed on strength outcomes. The whole transcriptome effects of calcifediol and placebo were very weak. Correcting for multiple testing using false discovery rate did not yield any differentially expressed genes using any sensible cut-offs. P-values were uniformly distributed across all genes, suggesting that low p-values are likely to be false positives. Partial least squares-discriminant analysis and principle component analysis was unable to separate treatment groups. Calcifediol supplementation did not affect the skeletal muscle transcriptome in frail older adults. Our findings indicate that vitamin D supplementation has no effects on skeletal muscle gene expression, suggesting that skeletal muscle may not be a direct target of vitamin D in older adults

Software en energiegebruik

Scientific publicatio