Anna Förster

FLEXOR: User friendly wireless sensor network development and deployment

Wireless sensor networks (WSNs) penetrated the market mainly as solutions for specific application scenarios. However, this strong specialization limits WSNs reuse both in terms of development as well as in terms of technical results: Every new application scenario requires a new design, development and validation, as well as management skills. This is frustrating for any WSNs user, developer or manager. To reverse this tendency and thus improve the quality of experience and user-friendliness in WSNs, we designed FLEXOR, a sustainable software architecture optimized to support the implementation, rapid prototyping, evaluation, and testing of wireless sensor network applications, that is platform independent and user-friendly. FLEXOR is designed to accommodate many different applications and services for wireless sensor networks and foster code re-usability and cross-platform component re-usability. FLEXOR offers high modularity, well defined interfaces, remote node management functionality as well as run-time module exchange. Finally, the introduction of a unifying way for WSNs development opens to a higher homogeneity and thus to more easy comparison among different solutions. We present here an analysis of FLEXOR from these new angles and show how effective it is for several purposes and in particular for non-experts and in education.

Towards Realistic and Credible Wireless Sensor Network Evaluation

This position paper explores the problem of realistically evaluating wireless sensor network (WSN) applications, algorithms and protocols. It surveys the currently available techniques, such as simulators, testbeds and real world deployments and compares their properties and challenges. While we underline the significance of simulation tools, we also observe that the state of the art simulation models at all levels (from physical to application) still lack realistic behavior. To demonstrate this gap we performed a broad study of simulation models and real world behavior of wireless links and compared those in various settings, including outdoor environments and battery-based deployments. Based on the provided survey and wireless link case study, we outline a strategy of how to enable realistic, efficient, low-cost and repeatable WSN evaluation scenarios.

TEACHING THE INTERNET OF THINGS

Teaching the Internet of Things has become vital in engineering, but also very challenging. This is mainly due to the almost unbelievable variety of available systems, hardware and software components, and online resources. This column discusses how we, at the University of Bremen, approached this problem: with hands-on experience and concept abstraction.

Validating Contact Times Extracted from Mobility Traces

Use of mobility models to model user movement in mobile networks is a key aspect when developing and evaluating networking protocols in simulators. A trace obtained from an actual user movement is considered as being more realistic than using synthetic mobility models in simulators. Though realistic, usually, these traces lack information about the actual wireless contact durations between users. Most simulators use Unit Disk Graph (UDG) model to determine contact durations. However, due to the nature of radio propagations, a simplistic connectivity model (with UDG) may result in simulating unrealistic connectivity patterns. In this work, we have used an Android Smartphone application to collect GPS traces of moving users and their corresponding Bluetooth Low Energy (BLE) contact times to compare the viability of using UDG to determine contact durations. The results show that trace based model with UDG based wireless connectivity is an effective method to determine contact durations.

Mobility as the Main Enabler of Opportunistic Data Dissemination in Urban Scenarios

The use of opportunistic communications to disseminate common interest messages in an urban scenario have various applications, like sharing traffic status, advertising shop offers, spread alarms, and so on. In this paper, we evaluate the combined use of fixed and mobile nodes to establish an optimal urban opportunistic network aimed at the distribution of general interest data.

DICE: A Novel Platform to Support Massively Distributed Clouds

Massively distributed clouds (MDC) have a huge potential in serving novel applications and services in many situations. Mainly, they are able to provide communication without the use of an infrastructure and to guarantee full data and user anonymity. However, their implementation is not trivial and requires innovation in many different fields, such as opportunistic communications, big data management and security. In this paper, we present our first design of a MDC supporting architecture, called DICE: Distributed Infrastructureless Cloud sErvices. We present our main application scenario and focus on implementation challenges and early results.

A TinyOS based tool for gathering real-world wireless traces

This paper presents a user-friendly TinyOS and Java-based tool for hassel-free collection of real-world wireless traces from any real-world environment (indoor or outdoor).

TRAILS - A Trace-Based Probabilistic Mobility Model

Modeling mobility is a key aspect when simulating different types of networks. To cater to this requirement, a large number of models has emerged in the last years. They are typically (a) trace-based, where GPS recordings are re-run in simulation, (b) synthetic models, which describe mobility with formal methods, or (c) hybrid models, which are synthetic models based on statistically evaluated traces. All these families of models have advantages and disadvantages. For example, trace-based models are very inflexible in terms of simulation scenarios, but have realistic behaviour, while synthetic models are very flexible, but lack realism. In this paper, we propose a new mobility model, called TRAILS (TRAce-based ProbabILiStic Mobility Model), which bridges the gap between these families and combines their advantages into a single model. The main idea is to extract a mobility graph from real traces and to use it in simulation to create scalable, flexible simulation scenarios. We show that TRAILS is more realistic than synthetic models, while achieving full scalability and flexibility. We have implemented and evaluated TRAILS in the OMNeT++ simulation framework.

Comparative Analysis of Opportunistic Communication Technologies

Opportunistic or device-to-device communications offer a great chance for straight-forward and cost-effective interoperability among various devices and manufacturers, from tiny sensors to end-used smartphones. However, their implementation is not trivial, as no standard communication technologies exist for their purposes. This paper explores the available options, qualitatively compares their properties, focusing especially on power consumption and user friendliness. We also offer an experimental comparison of their energy consumption and discuss further needed developments.

Panel: Student Competitions to Motivate Research in Wireless Sensor Networks

In this panel, we would like to discuss the current state of education activities in the area of wireless sensor networks (WSN) around the world. The main identified issue is the lack of motivation for long-term student oriented research projects. This leads to fragmented efforts with little usage of already achieved results. Competitions typically offer a greta opportunity for students, but are hard to design for WSN scenarios.