Antitrust, the Gig Economy, and Labor Market Power

The purpose of the current study was to develop and validate an automatic algorithm for classification of cross-country (XC) ski-skating gears (G) using Smartphone accelerometer data. Eleven XC skiers (seven men, four women) with regional-to-international levels of performance carried out roller skiing trials on a treadmill using fixed gears (G2left, G2right, G3, G4left, G4right) and a 950-m trial using different speeds and inclines, applying gears and sides as they normally would. Gear classification by the Smartphone (on the chest) and based on video recordings were compared. Formachine-learning, a collective database was compared to individual data. The Smartphone application identified the trials with fixed gears correctly in all cases. In the 950-m trial, participants executed 140 ± 22 cycles as assessed by video analysis, with the automatic Smartphone application giving a similar value. Based on collective data, gears were identified correctly 86.0% ± 8.9% of the time, a value that rose to 90.3% ± 4.1% (P < 0.01) with machine learning from individual data. Classification was most often incorrect during transition between gears, especially to or from G3. Identification was most often correct for skiers who made relatively few transitions between gears. The accuracy of the automatic procedure for identifying G2left, G2right, G3, G4left and G4right was 96%, 90%, 81%, 88% and 94%, respectively. The algorithm identified gears correctly 100% of the time when a single gear was used and 90% of the time when different gears were employed during a variable protocol. This algorithm could be improved with respect to identification of transitions between gears or the side employed within a given gear

Underwater 3-D imaging with laser triangulation

The objective of this master thesis was to study the performance of an active triangulation system for 3-D imaging in underwater applications. Structured light from a 20 mW laser and a conventional video camera was used to collect data for generation of 3-D images. Different techniques to locate the laser line and transform it into spatial coordinates were developed and evaluated. A field- and a laboratory trial were performed. From the trials we can conclude that the distance resolution is much higher than the lateral- and longitudinal resolution. The lateral resolution can be improved either by using a high frame rate camera or simply by using a low scanning speed. It is possible to obtain a range resolution of less than a millimeter. The maximum range of vision was 5 meters under water measured on a white target and 3 meters for a black target in clear sea water. These results are however dependent on environmental and system parameters such as laser power, laser beam divergence and water turbidity. A higher laser power would for example increase the maximum range

RATAD Reliability And Timing Analysis of Distributed systems

Modelling and analysis are important tools in the development of safety critical real-time systems. The introduction of state-of-the-art analysis techniques in industry is however rather slow. One reason for this is the pessimism in models and analysis, e.g., schedulability analysis for realistic systems are typically based on simplifying assumptions which leads to pessimism that forces designers to make costly overdesigns, dimensioning the system for worst-case situations that may never occur. At the same time, the over all system requirement is to satisfy a reliability measure of, say, at most 10-9 faults per hour. This project proposes a reliability analysis method that considers the effects of faults and timing parameter distributions (including execution time distributions, jitter distributions, and sporadic task inter-arrival time distributions) on schedulability analysis. The goal is to provide designers with well founded support that allow them to make trade-offs between timing guarantees and reliability, i.e. by allowing occasional deadline misses a less costly implementation may be used, while still satisfying the over all reliability requirement. Furthermore, it is well-known in industry that a missed deadline in most cases will not lead to a failure. This and other properties of executions will be considered. The work will have both theoretical and practical impact, since it will evaluate a new approach for integrating reliability modelling and schedulability analysis, and enable industry to use modern analysis techniques both to model components and systems in early design phases and to validate these models by measurements on the developed components/system. We apply for funding of one graduate student to develop a method for integrating schedulability analysis in reliability modelling. The result will be a unified framework for holistic analysis of systems ’ timing and reliability behaviour.

Timed Automata as Task Models for Event-Driven Systems

In this paper, we extend the classic model of timed automata with a notion of real time tasks. The main idea is to associate each discrete transition in a timed automaton with a task (an executable program). Intuitively, a discrete transition in an extended timed automaton denotes an event releasing a task and the guard on the transition specifies all the possible arriving times of the event (instead of the so-- called minimal inter-arrival time). This yields a general model for hard real-time systems in which tasks may be periodic and non-periodic