TY - THES A1 - Peintner, Daniel T1 - Efficient Exchange and Processing of Semi-structured Data in the Embedded Domain T1 - Effizienter Austausch and Verarbeitung von semistrukturierten Daten in eingebetteten Systemen N2 - The Internet is a global system of interconnected computers and computer networks where semi-structured data has been successfully applied for exchanging information. In nowadays Internet the huge range of actors, the large diversity of the associated device classes and domains, and the enormous amount of resource-restricted controllers in this system created new requirements and coined also a new term. Internet of Things (IoT), in this regard, refers to identifiable objects (things) and their virtual representations in an Internet-like structure. The fundamental question the thesis tries to answer is whether and how the same semi-structured data can be also applied to the IoT and the embedded domain in spite of resource-limited controllers. In order to discuss this question properties and requirements of embedded networks with regard to the IoT domain have been collected and evaluated. Thereafter the omnipresent semi-structured data exchange format in the Web, the Extensible Markup Language (XML), has been validated. The result was a list of missing requirements such as a compact representation, a representation that can be generated and consumed fast and also allows a small footprint implementation. To address the compiled requirements a binary representation of XML which nowadays is known as W3Cs Efficient XML Interchange (EXI) format has been accomplished which simultaneously optimizes performance and the utilization of computational resources and is designed to be compatible with XML. Moreover, in this work the format has been practically validated and tested. Addressing the needs of the embedded domain one result of this analyzes were optimizations to constrain runtime memory usage and to predict memory growth at runtime. A concept introduced in this thesis is LazyDOM which reduces memory requirements when processing and querying data. By means of a newly proposed code generation technique processing of EXI on ultra-constrained device classes has been enabled and resulting format modifications have been adopted by the W3C standardization. The research work described in this thesis on efficiently exchanging and processing semi-structured data on constrained embedded devices has not only triggered modifications in the W3C EXI format but even is already adopted in domain specific application standards and implementations. The above mentioned optimizations such as predictably limit the memory growth at runtime have been contributed, discussed and evaluated by the W3C experts and become a core part of the EXI specification. Even more significantly from the IoT perspective these optimizations provide the basis for the adoption of this technology in ISO and IEC standardization which is the first time for automotive and power industry to use IoT in the control plane. The implementation of EXI to conduct the evaluation as part of this thesis has become the de-facto open source reference implementation of EXI and became the basis of a number of other reference implementations such as the OpenV2G project that provides the reference implementation of the communication interface in ISO/IEC 15118. In summary the conducted research work has evaluated the options to adapt semi-structured data for the constrained embedded domain, proposed modifications and evaluated those under realistic conditions. This made it relevant for the technology as well as for application standardization despite the short period of this work. As such the research can now be taken as a basis for further challenges in the IoT field namely adopting concepts of the Semantic Web and adapting those to stimulate the quickly expanding eco-system of embedded devices. KW - Mikrocontroller KW - XML KW - Strukturierte Daten KW - Effizienzsteigerung KW - World-Wide Web Consortium KW - Binäres XML KW - EXI KW - Efficient XML Interchange KW - Eingebettete Systeme KW - Binary XML KW - EXI KW - Efficient XML Interchange KW - Embedded Networks Y1 - 2014 UR - https://opus4.kobv.de/opus4-uni-passau/frontdoor/index/index/docId/241 UR - https://nbn-resolving.org/urn:nbn:de:bvb:739-opus-27610 ER -