middleware for cooperating mobile embedded systems

Mobile embedded systems, wireless communication, real-time systems, real-time scheduling, communication protocols, cooperation, reliability and fault-tolerance, middleware

Robust acoustic and semantic modeling in a telephone-based spoken dialog system

Magdeburg, Univ., Fak. für Elektrotechnik und Informationstechnik, Diss., 2009

Gradient injection in preparative chromatography : exploitation of sample solvents different than the mobile phase

Magdeburg, Univ., Fak. für Verfahrens- und Systemtechnik, Diss., 2010

Best-Practice - Mobile Testing Viewing mobile usability studies with the example of an eyetracking study in the retail sector

Today, usability testing in the development of software and systems is essential. A stationary usability lab offers many different possibilities in the evaluation of usability, but it reaches its limits in terms of flexibility and the experimental conditions. Mobile usability studies consider consciously outside influences, and these studies require a specially adapted approach to preparation, implementation and evaluation. Using the example of a mobile eye tracking study the difficulties and the opportunities of mobile testing are considered.

Using information from telephone panel surveys to predict reasons for refusal

One of the key problems in conducting surveys is convincing people to participate.¦However, it is often difficult or impossible to determine why people refuse. Panel surveys¦provide information from previous waves that can offer valuable clues as to why people¦refuse to participate. If we are able to anticipate the reasons for refusal, then we¦may be able to take appropriate measures to encourage potential respondents to participate¦in the survey. For example, special training could be provided for interviewers¦on how to convince potential participants to participate.¦This study examines different influences, as determined from the previous wave,¦on refusal reasons that were given by the respondents in the subsequent wave of the¦telephone Swiss Household Panel. These influences include socio-demography, social¦inclusion, answer quality, and interviewer assessment of question understanding and¦of future participation. Generally, coefficients are similar across reasons, and¦between-respondents effects rather than within-respondents effects are significant.¦While 'No interest' reasons are easier to predict, the other reasons are more situational. Survey-specific issues are able to distinguish¦different reasons to some extent.

Devolution & Entrenched Household Poverty: Is Scotland less mobile?

The Scottish National Party led Scottish Government has identified household poverty as a key focus for its anti-poverty strategy. The government’s ‘Solidarity Target’ seeks to both increase wealth and increase the share of total income gained by these three deciles. The ability to demonstrate the advantages of policy divergence within Scotland, relative to the other parts of the United Kingdom, is central to the Government’s aim of gaining support for increased powers for the devolved government. This paper seeks to provide evidence on one aspect of the government’s anti- poverty strategy; the degree to which Scotland differs from the rest of the UK over levels of entrenched poverty. The paper demonstrates that not only does Scotland have greater entrenched poverty but that the changes in mobility since the 1990s have impacted on Scotland to a lesser degree than the rest of the UK.

Mobile termination and mobile penetration

In this paper, we study how access pricing affects network competition when subscription demand is elastic and each network uses non-linear prices and can apply termination-based price discrimination. In the case of a fixed per minute termination charge, we find that a reduction of the termination charge below cost has two opposing effects: it softens competition but helps to internalize network externalities. The former reduces mobile penetration while the latter boosts it. We find that firms always prefer termination charge below cost for either motive while the regulator prefers termination below cost only when this boosts penetration. Next, we consider the retail benchmarking approach (Jeon and Hurkens, 2008) that determines termination charges as a function of retail prices and show that this approach allows the regulator to increase penetration without distorting call volumes.

Effects of different Incentives on Attrition and Fieldwork Effort in Telephone Household Panel Surveys

Little is known about sample behavior and fieldwork effects of different incentives introduced in a household panel survey. This is especially true for telephone surveys. In a randomized experiment, the Swiss Household Panel implemented one prepaid and two promised nonmonetary incentives in the range of 10 to 15 Swiss Francs (7-10 e), plus a no incentive control group. The aim of the paper is to compare effects of these incentives especially on cooperation, but also on sample selection and fieldwork effort, separated by the household and the subsequent individual level. We find small positive cooperation effects of the prepaid incentive on both the household and the individual level especially in larger households. Sample composition is affected to a very minor extent. Finally, incentives tend to save fieldwork time and partially the number of contacts needed on the individual level.

Mobile termination, network externalities, and consumer expectations

We re-examine the literature on mobile termination in the presence of network externalities. Externalities arise when firms discriminate between on- and off-net calls or when subscription demand is elastic. This literature predicts that profit decreases and consumer surplus increases in termination charge in a neighborhood of termination cost. This creates a puzzle since in reality we see regulators worldwide pushing termination rates down while being opposed by network operators. We show that this puzzle is resolved when consumers' expectations are assumed passive but required to be fulfilled in equilibrium (as defined by Katz and Shapiro, AER 1985), instead of being rationally responsive to non-equilibrium prices, as assumed until now.

Body mass index: comparing mean values and prevalence rates from telephone and examination surveys.

BACKGROUND: Cost effective means of assessing the levels of risk factors in the population have to be defined in order to monitor these factors over time and across populations. This study is aimed at analyzing the difference in population estimates of the mean levels of body mass index (BMI) and the prevalences of overweight, between health examination survey and telephone survey. METHODS: The study compares the results of two health surveys, one by telephone (N=820) and the other by physical examination (N=1318). The two surveys, based on independent random samples of the population, were carried out over the same period (1992-1993) in the same population (canton of Vaud, Switzerland). RESULTS: Overall participation rates were 67% and 53% for the health interview survey (HIS) and the health examination survey (HES) respectively. In the HIS, the reporting rate was over 98% for weight and height values. Self-reported weight was on average lower than measured weight, by 2.2 kg in men and 3.5 kg in women, while self-reported height was on average greater than measured height, by 1.2 cm in men and 1.9 cm in women. As a result, in comparison to HES, HIS led to substantially lower mean levels of BMI, and to a reduction of the prevalence rates of obesity (BMI>30 kg/m(2)) by more than a half. These differences are larger for women than for men. CONCLUSION: The two surveys were based on different sampling procedures. However, this difference in design is unlikely to explain the systematic bias observed between self-reported and measured values for height and weight. This bias entails the overall validity of BMI assessment from telephone surveys.

Information Mobility: Information Dissemination in Mobile Networks

En el nostre projecte, considerem un escenari urbà o interurbà on persones amb dispositius mòbils (smartphones) o vehicles equipats amb interfícies de comunicació, estan interessats en compartir fitxers entre ells o descarregar-los al creuar Punts d’Accés (APs) propers a la carretera. Estudiem la possibilitat d’utilizar la cooperació en les trobades casuals entre nodes per augmentar la velocitat de descàrrega global. Amb aquest objectiu, plantejem algoritmes per a la selecció de quins paquets, per a quins destins i quins transportistes s’escullen en cada moment. Mitjançant extenses simulacions, mostrem com les cooperacions carry&forward dels nodes augmenten significativament la velocitat de descàrrega dels usuaris, i com aquest resultat es manté per a diversos patrons de mobilitat, col•locacions d'AP i càrregues de la xarxa. Per altra banda, aparells com els smartphones, on la targeta de WiFi està encesa contínuament, consumeixen l'energia de la bateria en poques hores. En molts escenaris, una targeta WiFi sempre activa és poc útil, perque sovint no hi ha necessitat de transmissió o recepció. Aquest fet es veu agreujat en les Delay Tolerant Networks (DTN), on els nodes intercanvien dades quan es creuen i en tenen l’oportunitat. Les tècniques de gestió de l’estalvi d’energia permeten extendre la duració de les bateries. El nostre projecte analitza els avantatges i inconvenients que apareixen quan els nodes apaguen períodicament la seva targeta wireless per a estalviar energia en escenaris DTN. Els nostres resultats mostren les condicions en que un node pot desconnectar la bateria sense afectar la probabilitat de contacte amb altres nodes, i les condicions en que aquesta disminueix. Per exemple, es demostra que la vida del node pot ser duplicada mantenint la probabilitat de contacte a 1. I que aquesta disminueix ràpidament en intentar augmentar més la vida útil.

Adaptive Privacy Management System Design For Context-Aware Mobile Devices

While mobile technologies can provide great personalized services for mobile users, they also threaten their privacy. Such personalization-privacy paradox are particularly salient for context aware technology based mobile applications where user's behaviors, movement and habits can be associated with a consumer's personal identity. In this thesis, I studied the privacy issues in the mobile context, particularly focus on an adaptive privacy management system design for context-aware mobile devices, and explore the role of personalization and control over user's personal data. This allowed me to make multiple contributions, both theoretical and practical. In the theoretical world, I propose and prototype an adaptive Single-Sign On solution that use user's context information to protect user's private information for smartphone. To validate this solution, I first proved that user's context is a unique user identifier and context awareness technology can increase user's perceived ease of use of the system and service provider's authentication security. I then followed a design science research paradigm and implemented this solution into a mobile application called "Privacy Manager". I evaluated the utility by several focus group interviews, and overall the proposed solution fulfilled the expected function and users expressed their intentions to use this application. To better understand the personalization-privacy paradox, I built on the theoretical foundations of privacy calculus and technology acceptance model to conceptualize the theory of users' mobile privacy management. I also examined the role of personalization and control ability on my model and how these two elements interact with privacy calculus and mobile technology model. In the practical realm, this thesis contributes to the understanding of the tradeoff between the benefit of personalized services and user's privacy concerns it may cause. By pointing out new opportunities to rethink how user's context information can protect private data, it also suggests new elements for privacy related business models.