An Improved Point-Line Incidence Bound Over Arbitrary Fields

We prove a new upper bound for the number of incidences between points and lines in a plane over an arbitrary field $\mathbb{F}$, a problem first considered by Bourgain, Katz and Tao. Specifically, we show that $m$ points and $n$ lines in $\mathbb{F}^2$, with $m^{7/8}<n<m^{8/7}$, determine at most $O(m^{11/15}n^{11/15})$ incidences (where, if $\mathbb{F}$ has positive characteristic $p$, we assume $m^{-2}n^{13}\ll p^{15}$). This improves on the previous best known bound, due to Jones. To obtain our bound, we first prove an optimal point-line incidence bound on Cartesian products, using a reduction to a point-plane incidence bound of Rudnev. We then cover most of the point set with Cartesian products, and we bound the incidences on each product separately, using the bound just mentioned. We give several applications, to sum-product-type problems, an expander problem of Bourgain, the distinct distance problem and Beck's theorem.Comment: 18 pages. To appear in the Bulletin of the London Mathematical Societ

Multifaceted companion devices: applying the new model of media attendance to smartphone usage

This study inspects the relationship between outcome expectations, habit strength, and smartphone usage by attempting to validate the new model of media attendance (NMMA) (LaRose and Eastin, 2004) , a social-cognitive theory of uses and gratifications. The fast adoption rate of smartphones, and their inherent characteristics as convergent, always-on, always-connected devices, warrant a closer look into user habitualization of this medium. Using a sample of 481 smartphone users selected from a larger panel, we were able to support the NMMA, although surprisingly no significant effect of habit strength on smartphone usage was found. While some uncertainties connected to the method are noted, this suggests a more complex reality, in which habitualization of a convergent media device does not necessarily implicate a significant rise in usage

Fast dynamic deployment adaptation for mobile devices

Mobile devices that are limited in terms of CPU power, memory or battery power are only capable of executing simple applications. To be able to run advanced applications we introduce a framework to split up the application and execute parts on a remote server. In order to dynamically adapt the deployment at runtime, techniques are presented to keep the migration time as low as possible and to prevent performance loss while migrating. Also methods are presented and evaluated to cope with applications generating a variable load, which can lead to an unstable system

The role of an omnipresent pocket device : smartphone attendance and the role of user habits

Smartphones are convergent, always-on pocket devices that have taken up an important role in the life of their users. This warrants a closer look into how this medium is used in every-day situations. Are goal-oriented incentives the main drive for smartphone usage, or do habits play a critical role? This study with 481 Belgian smartphone users attempts to describe the precedents of smartphone attendance by validating the model of media attendance (MMA), a social-cognitive theory of uses and gratifications (LaRose & Eastin, 2004). We surprisingly did not find evidence for a significant effect of habits on smartphone usage. We suggest two explanations. First, we suggest some uncertainties concerning the MMA methodology. Second, we suggest a more complex reality in which several habitual use patterns are shaped, dependent on user, context and device. This warrants a more in-depth study, using more advanced measures for smartphone usage and habit strength

Monte Carlo algorithm for the evaluation of the distance estimation variance in RSS-based visible light positioning

In this work, the Monte Carlo algorithm to determine the variance on the distance estimation in Received Signal Strength-based visible light positioning is considered. The method is build on the maximization of the signal-to-noise-ratio by means of matched filtering, and leads to a number of characteristics that are typically only obtained after intensive analytical elaborations. It is shown that the results match those obtained by calculating the Cramer-Rao lower bound when only the noise is considered as non-deterministic. It is demonstrated that the method is also applicable when multiple physical parameters exhibit a probability distribution, leading to an assessment of the distance estimation accuracy in more realistic settings

Quality assessment and usage behavior of a mobile voice-over-IP service

Voice-over-IP (VoIP) services offer users a cheap alternative to the traditional mobile operators to make voice calls. Due to the increased capabilities and connectivity of mobile devices, these VoIP services are becoming increasingly popular on the mobile platform. Understanding the user's usage behavior and quality assessment of the VoIP service plays a key role in optimizing the Quality of Experience (QoE) and making the service to succeed or to fail. By analyzing the usage and quality assessments of a commercial VoIP service, this paper identifies device characteristics, context parameters, and user aspects that influence the usage behavior and experience during VoIP calls. Whereas multimedia services are traditionally evaluated by monitoring usage and quality for a limited number of test subjects and during a limited evaluation period, this study analyzes the service usage and quality assessments of more than thousand users over a period of 120 days. This allows to analyze evolutions in the usage behavior and perceived quality over time, which has not been done up to now for a widely-used, mobile, multimedia service. The results show a significant evolution over time of the number of calls, the call duration, and the quality assessment. The time of the call, the used network, and handovers during the call showed to have a significant influence on the users' quality assessments

Synthesis and analysis of stable isotope-labelled N-acyl homoserine lactones

Aliphatic aldehydes were deuterated at the alpha-position via a base-catalyzed exchange reaction with D2O. These deuterated building blocks were used for the synthesis of labelled analogues of quorum sensing signal molecules belonging to the three major classes of naturally occurring N-acylated homoserine lactones (AHLs), with the label on a non-enolizable and therefore stable position. Besides the application of these stable isotope-labelled AHLs as a labelled standard for analysis via isotope dilution mass spectrometry, these compounds can be used to study the metabolic fate of the fatty acid tail of the AHL-molecule. These isotope-labelled compounds were fully characterized and used to synthesize the deuterated analogues of two commonly occurring AHL-degradation products, a tetramic acid and a ring opened N-acyl homoserine

Industry and engineering education interacting in an interregional project: a Flanders' perspective

The Interreg-IVa 2-Seas project i-MOCCA (“interregional MObility and Competence Centers in Automation”) concentrates on two fast evolving topics in industrial automation: industrial data communication and embedded control [1]. Both require high-end training of practicing engineers in industry and demonstrators illustrating proof-of-principle of emerging technologies. The i-MOCCA project aims to develop competence centers in different universities in the coastal regions of the UK, France and Flanders, Belgium. The project started in July 2011 and ends in September 2014