A context -and template- based data compression approach to improve resource-constrained IoT systems interoperability.

170 p.El objetivo del Internet de las Cosas (the Internet of Things, IoT) es el de interconectar todo tipo de cosas, desde dispositivos simples, como una bombilla o un termostato, a elementos más complejos y abstractoscomo una máquina o una casa. Estos dispositivos o elementos varían enormemente entre sí, especialmente en las capacidades que poseen y el tipo de tecnologías que utilizan. Esta heterogeneidad produce una gran complejidad en los procesos integración en lo que a la interoperabilidad se refiere.Un enfoque común para abordar la interoperabilidad a nivel de representación de datos en sistemas IoT es el de estructurar los datos siguiendo un modelo de datos estándar, así como formatos de datos basados en texto (e.g., XML). Sin embargo, el tipo de dispositivos que se utiliza normalmente en sistemas IoT tiene capacidades limitadas, así como recursos de procesamiento y de comunicación escasos. Debido a estas limitaciones no es posible integrar formatos de datos basados en texto de manera sencilla y e1ciente en dispositivos y redes con recursos restringidos. En esta Tesis, presentamos una novedosa solución de compresión de datos para formatos de datos basados en texto, que está especialmente diseñada teniendo en cuenta las limitaciones de dispositivos y redes con recursos restringidos. Denominamos a esta solución Context- and Template-based Compression (CTC). CTC mejora la interoperabilidad a nivel de los datos de los sistemas IoT a la vez que requiere muy pocos recursos en cuanto a ancho de banda de las comunicaciones, tamaño de memoria y potencia de procesamiento

A context -and template- based data compression approach to improve resource-constrained IoT systems interoperability.

170 p.El objetivo del Internet de las Cosas (the Internet of Things, IoT) es el de interconectar todo tipo de cosas, desde dispositivos simples, como una bombilla o un termostato, a elementos más complejos y abstractoscomo una máquina o una casa. Estos dispositivos o elementos varían enormemente entre sí, especialmente en las capacidades que poseen y el tipo de tecnologías que utilizan. Esta heterogeneidad produce una gran complejidad en los procesos integración en lo que a la interoperabilidad se refiere.Un enfoque común para abordar la interoperabilidad a nivel de representación de datos en sistemas IoT es el de estructurar los datos siguiendo un modelo de datos estándar, así como formatos de datos basados en texto (e.g., XML). Sin embargo, el tipo de dispositivos que se utiliza normalmente en sistemas IoT tiene capacidades limitadas, así como recursos de procesamiento y de comunicación escasos. Debido a estas limitaciones no es posible integrar formatos de datos basados en texto de manera sencilla y e1ciente en dispositivos y redes con recursos restringidos. En esta Tesis, presentamos una novedosa solución de compresión de datos para formatos de datos basados en texto, que está especialmente diseñada teniendo en cuenta las limitaciones de dispositivos y redes con recursos restringidos. Denominamos a esta solución Context- and Template-based Compression (CTC). CTC mejora la interoperabilidad a nivel de los datos de los sistemas IoT a la vez que requiere muy pocos recursos en cuanto a ancho de banda de las comunicaciones, tamaño de memoria y potencia de procesamiento

Using SWE Standards for Ubiquitous Environmental Sensing: A Performance Analysis

Although smartphone applications represent the most typical data consumer tool from the citizen perspective in environmental applications, they can also be used for in-situ data collection and production in varied scenarios, such as geological sciences and biodiversity. The use of standard protocols, such as SWE, to exchange information between smartphones and sensor infrastructures brings benefits such as interoperability and scalability, but their reliance on XML is a potential problem when large volumes of data are transferred, due to limited bandwidth and processing capabilities on mobile phones. In this article we present a performance analysis about the use of SWE standards in smartphone applications to consume and produce environmental sensor data, analysing to what extent the performance problems related to XML can be alleviated by using alternative uncompressed and compressed formats

RESTful Wireless Sensor Networks

Sensor networks have diverse structures and generally employ proprietary protocols to gather useful information about the physical world. This diversity generates problems to interact with these sensors since custom APIs are needed which are tedious, error prone and have steep learning curve. In this thesis, I present RESThing, a lightweight REST framework for wireless sensor networks to ease the process of interacting with these sensors by making them accessible over the Web. I evaluate the system and show that it is feasible to support widely used and standard Web protocols in wireless sensor networks. Being able to integrate these tiny devices seamlessly into the global information medium, we can achieve the Web of Things

MINDiT: A framework for media independent access to things

Deploying smart environments often implies a plethora of co-existing devices and services, each with their own set of features, requirements and interfacing characteristics. These intricate scenarios are further exacerbated when such devices are coupled with networking capabilities, globalizing their interaction opportunities to create the so-called Internet of Things. In such interconnected heterogeneous environments, the joint operation of entities requires a flexible framework that enables and simplifies interfacing between elements. In this paper, we propose MINDiT, a framework that provides a common abstract interface towards the communication support with different entities. It incorporates cross-layer mechanisms inspired on the existing IEEE 802.21 technology, suitably modified to facilitate and optimize deployment in scenarios featuring both high-level, and low-powered network-restricted entities. MINDiT was validated through a prototype built over an open-source IEEE 802.21 implementation. We further compared its signaling impact against other solutions, and evaluated its performance over a smart environment featuring a multimedia scenario with multiple devices and services

Ressourcen Optimierung von SOA-Technologien in eingebetteten Netzwerken

Embedded networks are fundamental infrastructures of many different kinds of domains, such as home or industrial automation, the automotive industry, and future smart grids. Yet they can be very heterogeneous, containing wired and wireless nodes with different kinds of resources and service capabilities, such as sensing, acting, and processing. Driven by new opportunities and business models, embedded networks will play an ever more important role in the future, interconnecting more and more devices, even from other network domains. Realizing applications for such types of networks, however, is a highly challenging task, since various aspects have to be considered, including communication between a diverse assortment of resource-constrained nodes, such as microcontrollers, as well as flexible node infrastructure. Service Oriented Architecture (SOA) with Web services would perfectly meet these unique characteristics of embedded networks and ease the development of applications. Standardized Web services, however, are based on plain-text XML, which is not suitable for microcontroller-based devices with their very limited resources due to XML's verbosity, its memory and bandwidth usage, as well as its associated significant processing overhead. This thesis presents methods and strategies for realizing efficient XML-based Web service communication in embedded networks by means of binary XML using EXI format. We present a code generation approach to create optimized and dedicated service applications in resource-constrained embedded networks. In so doing, we demonstrate how EXI grammar can be optimally constructed and applied to the Web service and service requester context. In addition, so as to realize an optimized service interaction in embedded networks, we design and develop an optimized filter-enabled service data dissemination that takes into account the individual resource capabilities of the nodes and the connection quality within embedded networks. We show different approaches for efficiently evaluating binary XML data and applying it to resource constrained devices, such as microcontrollers. Furthermore, we will present the effectful placement of binary XML filters in embedded networks with the aim of reducing both, the computational load of constrained nodes and the network traffic. Various evaluation results of V2G applications prove the efficiency of our approach as compared to existing solutions and they also prove the seamless and successful applicability of SOA-based technologies in the microcontroller-based environment

On the performance of markup language compression

Data compression is used in our everyday life to improve computer interaction or simply for storage purposes. Lossless data compression refers to those techniques that are able to compress a file in such ways that the decompressed format is the replica of the original. These techniques, which differ from the lossy data compression, are necessary and heavily used in order to reduce resource usage and improve storage and transmission speeds. Prior research led to huge improvements in compression performance and efficiency for general purpose tools which are mainly based on statistical and dictionary encoding techniques. Extensible Markup Language (XML) is based on redundant data which is parsed as normal text by general-purpose compressors. Several tools for compressing XML data have been developed, resulting in improvements for compression size and speed using different compression techniques. These tools are mostly based on algorithms that rely on variable length encoding. XML Schema is a language used to define the structure and data types of an XML document. As a result of this, it provides XML compression tools additional information that can be used to improve compression efficiency. In addition, XML Schema is also used for validating XML data. For document compression there is a need to generate the schema dynamically for each XML file. This solution can be applied to improve the efficiency of XML compressors. This research investigates a dynamic approach to compress XML data using a hybrid compression tool. This model allows the compression of XML data using variable and fixed length encoding techniques when their best use cases are triggered. The aim of this research is to investigate the use of fixed length encoding techniques to support general-purpose XML compressors. The results demonstrate the possibility of improving on compression size when a fixed length encoder is used to compressed most XML data types

Extending the Internet of Things to the future Internet through IPv6 Support

Emerging Internet of Things (IoT)/Machine-to-Machine (M2M) systems require a transparent access to information and services through a seamless integration into the Future Internet. This integration exploits infrastructure and services found on the Internet by the IoT. On the one hand, the so-called Web of Things aims for direct Web connectivity by pushing its technology down to devices and smart things. On the other hand, the current and Future Internet offer stable, scalable, extensive, and tested protocols for node and service discovery, mobility, security, and auto-configuration, which are also required for the IoT. In order to integrate the IoT into the Internet, this work adapts, extends, and bridges using IPv6 the existing IoT building blocks (such as solutions from IEEE 802.15.4, BT-LE, RFID) while maintaining backwards compatibility with legacy networked embedded systems from building and industrial automation. Specifically, this work presents an extended Internet stack with a set of adaptation layers from non-IP towards the IPv6-based network layer in order to enable homogeneous access for applications and services