Many underwater monitoring tasks, such as submarine life studies and pipeline inspections, are usually performed manually. Automated underwater monitoring has the potential to increase safety, improve timeliness, and decrease costs. We propose a hybrid solution of stationary sensor buoys and swarms of autonomous underwater vehicles (AUV) and report on our current progress of its realization. Our solution is based on sensor network technology and a small mobile underwater robot developed in our institute.

The Internet of Things (IoT) will connect billions of embedded computers that can sense and influence their environment. By integrating perception and control of the real world with data and services available on the Web, a wide range of novel applications can be realized, including Smart Cities, Smart Homes, or Smart Grids. A prerequisite for integrating sensor data with other data on the Web is a common data format that is not constrained to a specific domain, such that joint queries over diverse data sources can be efficiently performed. The Semantic Web offers such a data format called RDF, which essentially consists of subject-predicate-object triples to formulate arbitrary facts, as well as a query language called SPARQL to pose queries over sets of such triples. In order to scale to the huge amount of sensor data being produced in the IoT, RDF databases and SPARQL query engines need to be implemented in a distributed fashion, in particular using peer-to-peer (P2P) techniques. Existing solutions in that space offer only limited functionality and cannot be easily extended. Therefore, after surveying the state of the art, we propose a generic framework that fully supports SPARQL,but allows plugging in different P2P systems and distribution strategies.Wealso presentandevaluateanovel probabilistic distribution strategy that supports non-uniformly distributed RDF triples.

Article Testbed Runtime – The WISEBED WSN Testbed Infrastructure Software was published on February 1, 2013 in the journal PIK - Praxis der Informationsverarbeitung und Kommunikation (volume 36, issue 1).

This paper is based on two fundamental assumptions about a future Internet of Things (IoT): i) The amount of wireless, resource-constrained devices will outnumber the amount of devices in the current internet by several orders of magnitude and ii) those devices will be connected to the Internet over multi-hop wireless links. We argue that the experimental validation in testbeds is imperative to make those networks robust. However, there are only limited means to support researchers in “debugging” the actual communication on the wireless medium and often developers can only guess why their protocols don’t work in a given environment. In this paper, we present such a framework which extends the WISEBED testbed federation. Our contribution allows an easy-to-use browser-based experimentation and evaluation of wireless multi-hop protocols in all WISEBED-compatible testbeds (nine testbeds with 1000 sensor nodes and the SmartSantander [17] smart city testbed which will offer up to 20,000 IoT devices). Using a generic packet tracking framework for multiple platforms, researchers can easily detect hotspots and bottlenecks in the network and follow the routes of individual packets as they are forwarded. Experiment configurations can be shared on the web so that experiments can easily be repeated to verify published results. We demonstrate the usability of our approach by means of a real-world use-case.

Virtual testbeds model them by seamlessly integrating physical, simulated, and emulated sensor nodes and radios in real time.

The increasing convergence of the Internet as the global information backbone and embedded systems and sensors as key information providers on the state of the physical world to this backbone requires efficient design and implementation methodologies which do not exist to date. Currently, the development of applications spanning both worlds is cumbersome and inefficient due to the lack of suitable frameworks and the limited understanding of the two development communities for the problems and underlying assumptions which need to be taken into account of “on the other side of the fence.” The goal of any methodology should be to provide the elegance and widespread adaption of Web-based standards in combination with the efficiency of the underlying embedded system and sensor layers, abstracting away “unnecessary” details while providing powerful paradigms which enable the necessary level of control in terms of APIs. This paper investigates unified concepts, methods, and software infrastructures that support the efficient development of applications across the Internet and the embedded world, minimizing development efforts through flexible data and meta-data driven integration based on Semantic Web technologies.

Zusammenfassung Die experimentelle Validierung neuartiger Ansätze hat, besonders im Kontext des Internet der Dinge, stark an Bedeutung gewonnen. Dieser Beitrag identifiziert Anforderungen an Experimentaleinrichtungen für das Internet der Dinge, gibt einen Überblick über aktive und öffentlich zugängliche Experimentaleinrichtungen und stellt verschiedene Plattformen auf Basis dieser Anforderungen qualitativ gegenüber. Es wird beispielhaft auf eine der Plattformen (WISEBED) näher eingegangen, um den Lesern einen Eindruck zu vermitteln, welche Möglichkeiten der experimentellen Forschung heute bereits zur Verfügung stehen. Des Weiteren wird besprochen, wie eigene Testbeds auf Basis der WISEBED Software betrieben und – falls gewünscht – mit anderen föderiert werden können.

Based on technologies and algorithms that were developed about 30 years ago, today’s Internet is approaching the limits of its legacy architecture. This has spawned a wide range of intensive studies on the future internet, including the German-Lab (G-Lab) initiative.

The developed world is awash with sensors. However, they are typically locked into unimodal closed systems. To unleash their full potential, access to sensors should be opened such that their data and services can be integrated with data and services available in other information systems, facilitating novel applications and services that are based on the state of the real world. We describe our vision and architecture of a Semantic Web of Things: a service infrastructure that makes the deployment and use of semantic applications involving Internet-connected sensors almost as easy as building, searching, and reading a web page today.

The increasing convergence of the Internet as the global information backbone and embedded systems and sensors as key information providers on the state of the physical world to this backbone requires efficient design and implementation methodologies which do not exist to date. Currently, the development of applications spanning both worlds is cumbersome and inefficient due to the lack of suitable frameworks and the limited understanding of the two development communities for the problems and underlying assumptions which need to be taken into account of “on the other side of the fence.” The goal of any methodology should be to provide the elegance and widespread adaption of Web-based standards in combination with the efficiency of the underlying embedded system and sensor layers, abstracting away “unnecessary” details while providing powerful paradigms which enable the necessary level of control in terms of APIs. This paper investigates unified concepts, methods, and software infrastructures that support the efficient development of applications across the Internet and the embedded world, minimizing development efforts through flexible data and meta-data driven integration based on Semantic Web technologies.

In recent years Wireless Sensor Networks (WSNs) have enjoyed a growing amount of attention. One particularly promising prospect is to employ WSNs as an extension of the future internet into the real world; this motivates experimentally driven research to evaluate and benchmark new concepts on WSNs. With our poster we will show our approach to virtualizing Wireless Sensor Network testbeds. With this technique we are able to reconfigure the topology of a WSN testbed without changing the physical location of nodes; it even allows building virtual topologies on top of federated testbeds.

flexible experimentation in wireless sensor networks significant drawbacks when used in isolation (see the sidebar “Physical Testbeds vs. Simulation vs. Emulation”). Therefore, they seek to combine all three to enable a more complete evaluation of the system being developed. Unfortunately, each approach requires different coding styles and tools, forcing researchers to expend significant effort reimplementing their systems for different tools/ platforms/approaches. As a remedy, techniques have been developed to reduce the transitioning effort among the three approaches, but further work is needed to address the emerging requirement for more flexible experimental facilities. Our work abstracts the concept of testbeds to yield virtual testbeds (VTBs) programmed similarly regardless of whether their underlying realization is physical, simulated, or emulated. VTBs are private, custom-designed, per-experiment, virtualized testbed instances that enable developers to seamlessly combine and/or interchange physical elements, including sensor nodes and radios, with simulations and emulations of these elements. We are developing a reference implementation of the VTB abstraction on top of a large-scale federated physical testbed infrastructure (see Figure 1), augmenting the inherent flexibility of the VTB abstraction in terms of scalwIReLess sensoR neTwo RKs (WSNs) play a key role in the emerging “real-world Internet,” with several large-scale WSNs being deployed; see, for example, Bernat2 and Dudek et al.9 However, WSN development is inherently complex, involving hardware design, embedded and distributed programming, heterogeneity, scale, and unpredictable environmental changes. Addressing this complexity, testbed-based experimentation (recommended by Weiser) is increasingly the norm for developing and optimizing WSN systems in a controllable environment prior to deployment. The WSN research community has historically relied on three main approaches to testbed-based experimentation: physical, simulation, and emulation. However, researchers appreciate that each involves key insights

Recently, experimentally-driven research has become an instrumental tool in designing and optimizing novel networking applications. While simulations are still important tools, they suffer from several imperfections as they make artificial assumptions on radio propagation, traffic, failure patterns, and topologies. Especially in the domain of wireless sensor networks, which are embedded into the environment, applications strongly depend on real-world processes that are often a result of complex interactions and are extremely difficult to model accurately. In order to design robust applications, developers need appropriate tools and methods for testing and managing their applications on real hardware in large-scale deployments. Such tools have been developed by the EUproject WISEBED [Sev08], which provides methods to cope with implementing protocols and applications for heterogeneous networks (cf. Chapter 2.0) as well as an ecosystem of testbeds and accompanying software for conducting experiments. This chapter introduces the latter and describes requirements for testbeds and WISEBED’s architecture (cf. Section 9.2), how to run experiments (cf. Section 9.3), and briefly how to operate testbeds using the WISEBED software (cf. Section 9.4). Section 9.5 concludes this chapter.

Current surveys and forecast predict that the number of wireless devices is going to increase tremendously. These wireless devices can be computers of all kinds, notebooks, netbooks, Smartphones and sensor nodes that evolve into real-world scenarios forming a “Real-World-Internet” in the future. In our work we focus on the Future Internet with small battery driven devices forming the “Internet of Things”. In recent networking research, testbeds gain more and more attention, especially in the context of Future Internet and wireless sensor networks (WSNs). This development stems from the fact that simulations and even emulations are not considered sufficient for the deployment of new technologies as they often lack realism. Experimental research on testbeds is a promising alternative that can help to close the gap. The deployment of testbeds is challenging and user and operator requirements need to be considered carefully. Therefore, the goal is to design an architecture that allows operators of WSN testbeds to offer numerous users access to their testbeds in a standardized flexible way that matches these requirements. In this paper we first identify some of the requirements, then introduce the architecture and general concepts of our WISEBED approach and show how this architecture meets the requirements of both groups. We give an overview of existing WISEBED-compatible WSN testbeds that can be used for experimentation today. Main focus in this paper compared to previous work is to address the perspective of both users and operators on how to experiment or respectively operate a WSN testbed based on WISEBED technology.

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We present an architecture for the interconnection of simulated sensor nodes and real node hardware. The simulator is therefore running in real-time, and the simulated nodes are able to exchange messages with real sensor nodes as if they were sent over the radio. This runs fully transparent for the application--and is well suitable for debugging purposes and general algorithm development. It is even possible to use exactly the same algorithm implementation for both simulated nodes and real sensors.

There is an increasing trend to integrate sensor networks into the Internet, eventually resulting in an Internet of Things. Recent efforts of porting IPv6 to sensor networks turn sensor nodes into equitable Internet peers and RESTful Web Services on sensor nodes allow a distribution of the application logic among sensor nodes and more powerful Internet nodes. The touching point between a sensor network and the Internet is the gateway which translates between the link-layer protocols used in the Internet (Ethernet, Wi-Fi) and sensor networks (IEEE 802.15.4). So far, the functionality of those gateways was fixed and simple. We propose to turn these gateways into smart gateways by enabling them to execute application code. As only the gateway has full knowledge of and control over both the sensor network and the Internet, smart gateways can act as performance-enhancing proxies and intelligent caches to preserve the limited resources of the sensor network. Also, the smart gateway can perform application-specific protocol conversion between highly optimized but non-standard protocols in the sensor network and standardized, but less efficient protocols in the Internet. In this paper we present the design of a middleware for smart gateways that allows the execution of application code on the gateway by offering simplified interfaces to the sensor network and the Internet. We also report preliminary performance results for key functions of the middleware.

The emerging Future Internet will bring a number of new challenges due to the inclusion of an enormous amount of distributed heterogenous mobile devices such as wireless sensor networks, mobile phones, and other sensor equipped embedded systems. Key challenges will be energy efficiency of protocols and algorithms due to the scarce resources of the used devices, the real-time search for real-world states as well as easy high-level application development. Real-World G-Lab will contribute to solutions of these problems by developing algorithms and techniques on different abstraction levels beginning from low level energy efficient protocols to high level application development.