A Decentralized Context Broker Using Byzantine Fault Tolerant Consensus

A context broker is a reliable message-relaying service used to connect devices by integrating all device protocols and communication methods, and reliably transporting messages while isolating data from other application service layers and networking complexities. A highly scalable decentralized context broker stack is composed of three layers—starting with a peer-to-peer network connecting a byzantine fault-tolerant (i.e., blockchain-based) consensus protocol—and it manages the communication using a web-socket streaming protocol as interface to other applications. This paper presents such a concept for a decentralized context broker stack for intercommunication between heterogeneous materials handling systems, and deploys the stack as proof-of-concept using ROS-based robots in a logistics scenario

PhyNetLab: An IoT-Based Warehouse Testbed

Future warehouses will be made of modular embedded entities with communication ability and energy aware operation attached to the traditional materials handling and warehousing objects. This advancement is mainly to fulfill the flexibility and scalability needs of the emerging warehouses. However, it leads to a new layer of complexity during development and evaluation of such systems due to the multidisciplinarity in logistics, embedded systems, and wireless communications. Although each discipline provides theoretical approaches and simulations for these tasks, many issues are often discovered in a real deployment of the full system. In this paper we introduce PhyNetLab as a real scale warehouse testbed made of cyber physical objects (PhyNodes) developed for this type of application. The presented platform provides a possibility to check the industrial requirement of an IoT-based warehouse in addition to the typical wireless sensor networks tests. We describe the hardware and software components of the nodes in addition to the overall structure of the testbed. Finally, we will demonstrate the advantages of the testbed by evaluating the performance of the ETSI compliant radio channel access procedure for an IoT warehouse

Offloading Safety- and Mission-Critical Tasks via Unreliable Connections

For many cyber-physical systems, e.g., IoT systems and autonomous vehicles, offloading workload to auxiliary processing units has become crucial. However, since this approach highly depends on network connectivity and responsiveness, typically only non-critical tasks are offloaded, which have less strict timing requirements than critical tasks. In this work, we provide two protocols allowing to offload critical and non-critical tasks likewise, while providing different service levels for non-critical tasks in the event of an unsuccessful offloading operation, depending on the respective system requirements. We analyze the worst-case timing behavior of the local cyber-physical system and, based on these analyses, we provide a sufficient schedulability test for each of the proposed protocols. In the course of comprehensive experiments, we show that our protocols have reasonable acceptance ratios under the provided schedulability tests. Moreover, we demonstrate that the system behavior under our proposed protocols is strongly dependent on probability of unsuccessful offloading operations, the percentage of critical tasks in the system, and the amount of offloaded workload

An approach towards decentralization of systems communication in Industry 4.0

Decentralization of system communication of Industry 4.0 is the main thesis, where different types of system type topologies (Centralized, Distributed, and Decentralized) are explored. With the different topologies, the importance of systems decentralization in the context of logistics is explored for a socially networked industry. A socially networked industry is a hierarchical network of systems that collaborate and execute tasks with optimizations performed at every network level. To develop such a networking paradigm, decentralization is necessary, unfortunately it is not possible to provide the same strategies for all communicating systems. Therefore, the heterogeneous systems in logistics are classified broadly into two systems types based on the available communication data bandwidth and energy constraints. Upon classifying the systems into low power, low data-rate systems and high power, high data-rate systems, networking architecture for decentralized communication are developed. Two decentralized networking concepts are developed as part of this research work called the Decentralized Brains and the DezCom Context Broker, which is deployed in the industrial research facility of FLW, TU Dortmund. A sensor floor with 345 low power wireless sensor nodes is used to develop and evaluate the performance of Decentralized Brains, and a multi-robot system along with servers deployed in a cloud environment was used for analyzing dezCom context broker. Networking flooding primitive and decentralized networking software for low power wireless sensor networks were developed, and the codebase for Decentralized Brains is published. A guide for developing decentralized industrial applications is discussed with the advantages and disadvantages of developing decentralized applications for specific industrial use cases

Reference field for research and development of novel hybrid forms of human machine interaction in logistics

Der vorliegende Artikel beschreibt das Konzept eines derzeit im Aufbau befindlichen Forschungszentrums, das als neuartiges experimentelles Referenzfeld für innovative Dienstleistungen in der Intralogistik dient. Die Kernaufgabe des Zentrums besteht in der Erforschung eines hybriden Wertschöpfungsnetzwerks, in dem Menschen und Maschinen miteinander im Dialog stehen und gemeinsam Arbeitsaufgaben erledigen. Diese im Rahmen der vierten industriellen Revolution aufkommende neuartige Form hybrider Interaktion bringt neue Herausforderungen mit sich, die es wissenschaftlich zu untersuchen gilt. Beispielsweise entstehen durch den Einsatz von Echtzeit-Lokalisierungs- und Virtual-Reality-Systemen neue Möglichkeit im Bereich der Mensch-Maschine-Interaktion (Human-Machine-Interaction - HMI). Durch die Ausstattung des Forschungszentrums mit unterschiedlichen modular sowie frei skalierbaren Referenz- und Experimentiersystemen wird u. a. die Möglichkeit geschaffen, die zu untersuchenden Szenarien in Echtzeit zu simulieren und damit einen digitalen Zwilling der Realität zu erschaffen. Die vollständige Flexibilität der eingesetzten Systeme (flexible Systemvernetzung, flexible Nutzung der generierten Daten durch andere Systeme etc.) führt zu großen Datenmengen, die mit Hilfe von Machine-Learning- und Deep-Learning-Konzepten so kombiniert und aufbereitet werden sollen, dass neue Erkenntnisse gewonnen werden können. Die beschriebene Systemflexibilität führt u. a. zu der zentralen Herausforderung, eine gemeinsame Syntax für die Interoperabilität der eingesetzten Systeme zu generieren.The article describes the concept of a research center (currently under construction) that is going to be used as a novel experimental reference field for in-novative services in intralogistics. An important aim of the center is to enable research of hybrid value added networks, where humans and machines intimately cooperate with each other to complete work tasks together. In the context of Industry 4.0 this novel form of hybrid interaction entails new challenges that need to be further researched – for example, the use of real-time localization and virtual reality systems creates new possibilities in the field of human-machine interaction (HMI). Additionally, the research center is equipped with various modular and freely scalable reference and experiment systems that allows to emulate different real-time scenarios, including digital twin simulation concepts. The full system flexibility (flexible system networking, flexible use of generated data etc.) leads to high datasets. With the help of machine learning and deep learning concepts, new knowledge from this dataset can be extracted. The described system flexibility leads to new interoperability problems. In order to ensure the interoperability of the systems a common syntax has to be provided. Therefore, more research on this topic is needed

Responsive Space Structures: Modular, re-configurable tiles for microgravity self-assembly: Paper presented at 70th International Astronautical Congress 2019, 21-25 October 2019, Washington, D.C., USA

To achieve autonomous self-assembly of large scale space structures in orbit, we propose and are executing on a technology development roadmap where responsive sensing augments the physical shell material of modular space structures to guide tile navigation and neighbor-neighbor bonding. This facilitates decentralized, guided space structure construction independent of astronaut EVAs (extra-vehicular activities) and robotic agents, and robust to single part failure via a system of RF-enabled “smart assembly nodes.” This paper will describe the TESSERAE platform (Tessellated Electromagnetic Space Structures for the Exploration of Reconfigurable, Adaptive Environments) and present results from a 2019 testing campaign across microgravity parabolas and a suborbital rocket launch