Ordering Events Based on Intentionality in Cyber-Physical Systems

We consider cyber-physical systems (CPSs) comprising a central controller that might be replicated for high-reliability, and one or more process agents. The controller receives measurements from process agents, causing it to compute and issue setpoints that are sent back to process agents. The implementation of these setpoints causes a change in the state of the controlled physical process, and the new state is communicated to the controllers through resulting measurements. To ensure correct operation, the process agents must implement only those setpoints that were caused by their most recent measurements. However, in the presence of replication of the controller, network or computation delays, setpoints and measurements do not necessarily succeed in causing the intended behavior. To capture the dependencies among events associated with measurements and setpoints, we introduce the intentionality relation among such events in a CPS and illustrate its differences with respect to the happened-before relation. We propose a mechanism, intentionality clocks, and the design of controllers and process agents that can be used to guarantee the strong clock-consistency condition under the intentionality relation. Moreover, we prove that our design ensures correct operation despite crash, delay, and network faults. We also demonstrate the practical application of our abstraction through an illustration with a real-world CPS for electrical vehicles

Ordering Events Based on Intentionality in Cyber-Physical Systems

We consider cyber-physical systems (CPSs) comprising a central controller that might be replicated for high-reliability, and one or more process agents. The controller receives measurements from process agents, causing it to compute and issue setpoints that are sent back to process agents. The implementation of these setpoints causes a change in the state of the controlled physical process, and the new state is communicated to the controllers through resulting measurements. To ensure correct operation, the process agents must implement only those setpoints that were caused by their most recent measurements. However, in the presence of replication of the controller, network or computation delays, setpoints and measurements do not necessarily succeed in causing the intended behavior. To capture the dependencies among events associated with measurements and setpoints, we introduce the intentionality relation among such events in a CPS and illustrate its differences with respect to the happened-before relation. We propose a mechanism, intentionality clocks, and the design of controllers and process agents that can be used to guarantee the strong clock-consistency condition under the intentionality relation. Moreover, we prove that our design ensures correct operation despite crash, delay, and network faults. We also demonstrate the practical application of our abstraction through an illustration with a real-world CPS for electrical vehicles

Reliability Mechanisms for Controllers in Real-Time Cyber-Physical Systems

Cyber-physical systems (CPSs) are real-world processes that are controlled by computer algorithms. We consider CPSs where a centralized, software-based controller maintains the process in a desired state by exchanging measurements and setpoints with process agents (PAs). As CPSs control processes with low-inertia, e.g., electric grids and autonomous cars, the controller needs to satisfy stringent real-time constraints. However, the controllers are susceptible to delay and crash faults, and the communication network might drop, delay or reorder messages. This degrades the quality of control of the physical process, failure of which can result in damage to life or property. Existing reliability solutions are either not well-suited for real-time CPSs or impose serious restrictions on the controllers. In this thesis, we design, implement and evaluate reliability mechanisms for real-time CPS controllers that require minimal modifications to the controller itself. We begin by abstracting the execution of a CPS using events in the CPS, and the two inherent relations among those events, namely network and computation relations. We use these relations to introduce the intentionality relation that uses these events to capture the state of the physical process. Based on the intentionality relation, we define three correctness properties namely, state safety, optimal selection and consistency, that together provide linearizability (one-copy equivalence) for CPS controllers. We propose intentionality clocks and Quarts, and prove that they provide linearizability. To provide consistency, Quarts ensures agreement among controller replicas, which is typically achieved using consensus. Consensus can add an unbounded-latency overhead. Quarts leverages the properties specific to CPSs to perform agreement using pre-computed priorities among sets of received measurements, resulting in a bounded-latency overhead with high availability. Using simulation, we show that availability of Quarts, with two replicas, is more than an order of magnitude higher than consensus. We also propose Axo, a fault-tolerance protocol that uses active replication to detect and recover faulty replicas, and provide timeliness that requires delayed setpoints be masked from the PAs. We study the effect of delay faults and the impact of fault-tolerance with Axo, by deploying Axo in two real-world CPSs. Then, we realize that the proposed reliability mechanisms also apply to unconventional CPSs such as software defined networking (SDN), where the controlled process is the routing fabric of the network. We show that, in SDN, violating consistency can cause implementation of incorrect routing policies. Thus, we use Quarts and intentionality clocks, to design and implement QCL, a coordination layer for SDN controllers that guarantees control-plane consistency. QCL also drastically reduces the response time of SDN controllers when compared to consensus-based techniques. In the last part of the thesis, we address the problem of reliable communication between the software agents, in a wide-area network that can drop, delay or reorder messages. For this, we propose iPRP, an IP-friendly parallel redundancy protocol for 0 ms repair of packet losses. iPRP requires fail-independent paths for high-reliability. So, we study the fail-independence of Wi-Fi links using real-life measurements, as a first step towards using Wi-Fi for real-time communication in CPSs

Reliable and Robust Cyber-Physical Systems for Real-Time Control of Electric Grids

Real-time control of electric grids is a novel approach to handling the increasing penetration of distributed and volatile energy generation brought about by renewables. Such control occurs in cyber-physical systems (CPSs), in which software agents maintain safe and optimal grid operation by exchanging messages over a communication network. We focus on CPSs with a centralized controller that receives measurements from the various resources in the grid, performs real-time computations, and issues setpoints. Long-term deployment of such CPSs makes them susceptible to software agent faults, such as crashes and delays of controllers and unresponsiveness of resources, and to communication network faults, such as packet losses, delays, and reordering. CPS controllers must provide correct control in the presence of external non-idealities, i.e., be robust, and in the presence of controller faults, i.e., be reliable. In this thesis, we design, test, and deploy solutions that achieve these goals for real-time CPSs. We begin by abstracting a CPS for electric grids into four layers: the control layer, the network layer, the sensing and actuation layer, and the physical layer. Then, we provide a model for the components in each layer, and for the interactions among them. This enables us to formally define the properties required for reliable and robust CPSs. We propose two mechanisms, Robuster and intentionality clocks, for making a single controller robust to unresponsive resources and non-ideal network conditions. These mechanisms enable the controller to compute and issue setpoints even when some measurements are missing, rather than to have to wait for measurements from all resources. We show that our proposed mechanisms guarantee grid safety and outperform state-of-the-art alternatives. Then, we propose Axo: a framework for crash- and delay-fault tolerance via active replication of the controller. Axo ensures that faults in the controller replicas are masked from the resources, and it provides a mechanism for detecting and recovering faulty replicas. We prove the reliable validity and availability guarantees of Axo and derive the bounds on its detection and recovery time. We showcase the benefits of Axo via a stability analysis of an inverted pendulum system. Solutions based on active replication must guarantee that the replicas issue consistent setpoints. Traditional consensus-based schemes for achieving this are not suitable for real-time CPSs, as they incur high latency and low availability. We propose Quarts, an agreement mechanism that guarantees consistency and a low bounded latency- overhead. We show, via extensive simulations, that Quarts provides an availability at least an order of magnitude higher than state-of-the-art solutions. In order to test the effect of our proposed solutions on electric grids, we developed T-RECS, a virtual commissioning tool for software-based control of electric grids. T-RECS enables us to test the proper functioning of the software agents both in ideal and faulty conditions. This provides insight into the effect of faults on the grid and helps us to evaluate the impact of our reliability solutions. We show how our proposed solutions fit together, and that they can be used to design a reliable and robust CPS for real-time control of electric grids. To this end, we study a CPS with COMMELEC, a real-time control framework for electric grids via explicit power setpoints. We analyze the reliability issues..

The study of emoji linguistic behaviour: an examination of the theses raised (and not raised) in the academic literature

This bibliographic review of academic research on emoji reveals how the bulk of studies accepts it as a language but do not develop detailed linguistic analysis that could support this claim: they accept the clues provided by the initial studies, as if the scientific community had already reached such a consensus. However, the truth is that the fields in which emoji have generated the greatest academic interest (computer science, psychology and cognitive science) have considered the study of their linguistic nature a minor issue. Therefore, research on emoji has been growing over the years, widening the scope of its contributions, but with a common core made up of few basic notions about its linguistic condition that has important blind spots, in which Linguistics hasn’t done (generally) its work to place it in this new context for communication that the digital environments represent, despite the supports provided by multimodality and visual language theory. From these two disciplines, some authors have boldly suggested the emoji’s status as a gesture. However, to analyse its linguistic nature and behaviour, it is more accurate to understand the emoji, not as a gesture, but as a simplified representation of a gesture, without the unique features that a personal gesture has. The emoji seems to be the tool that, with fewer resources, best ensures that the interlocutor can understand the intentionality with which the sender has written the message

The study of emoji linguistic behaviour: an examination of the theses raised (and not raised) in the academic literature

This bibliographic review of academic research on emoji reveals how the bulk of studies accepts it as a language but do not develop detailed linguistic analysis that could support this claim: they accept the clues provided by the initial studies, as if the scientific community had already reached such a consensus. However, the truth is that the fields in which emoji have generated the greatest academic interest (computer science, psychology and cognitive science) have considered the study of their linguistic nature a minor issue. Therefore, research on emoji has been growing over the years, widening the scope of its contributions, but with a common core made up of few basic notions about its linguistic condition that has important blind spots, in which Linguistics hasn’t done (generally) its work to place it in this new context for communication that the digital environments represent, despite the supports provided by multimodality and visual language theory. From these two disciplines, some authors have boldly suggested the emoji’s status as a gesture. However, to analyse its linguistic nature and behaviour, it is more accurate to understand the emoji, not as a gesture, but as a simplified representation of a gesture, without the unique features that a personal gesture has. The emoji seems to be the tool that, with fewer resources, best ensures that the interlocutor can understand the intentionality with which the sender has written the message

The herd moves? Emergence and self-organization in collective actors?

The puzzle about collective actors is in the focus of this contribution. The first section enters into the question of the adequateness and inadequateness of reductionist explanations for the description of entities. The considerations in this part do not draw on systems and hence not on principles of self-organisation, because this concept necessitates a systemic view. In other words, the first section discusses reductionism and holism on a very general level. The scope of these arguments goes far beyond self-organising systems. Pragmatically, these arguments will be discussed within the domain of corporative actors. Emergence is a concept embedded in system theory. Therefore, in the second part the previous general considerations about holism are integrated with respect to the concept “emergence”. In order to close the argument by exactly characterising self-organising systems and giving the conceptual link between self-organisation and emergence – which is done in the section four – the third section generally conceptualises systems. This conceptualisation is independent of whether these systems are self-organising or not. Feedback loops are specified as an essential component of systems. They establish the essential precondition of system-theoretic models where causes may also be effects and vice versa. System-theory is essential for dynamic models like ecological models and network thinking. In the fourth part mathematical chaos-theory bridges the gap between the presentation of systems in general and the constricted consideration of self-organising systems. The capability to behave or react chaotically is a necessary precondition of self-organisation. Nevertheless, there are striking differences in the answers given from theories of self-organisation in biology, economics or sociology on the question “What makes the whole more than the sum of its parts?” The fracture seems particularly salient at the borderline between formal-mathematical sciences like natural sciences including economy and other social sciences like sociology, for instance in the understanding and conceptualisation of “chaos” or “complexity”. Sometimes it creates the impression that originally well defined concepts from mathematics and natural science are metaphorically used in social sciences. This is a further reason why this paper concentrates on conceptualisations of self-organisation from natural sciences. The fifth part integrates the arguments from a system-theoretic point of view given in the three previous sections with respect to collective and corporative actors. Due to his prominence all five sections sometimes deal with the sociological system theory by Niklas Luhmann, especially in those parts with rigorous and important differences between his conception and the view given in this text. Despite Luhmann’s undoubted prominence in sociology, the present text strives for a more analytical and formal understanding of social systems and tries to find a base for another methodological approach.

Tech Imaginations

Prof. Dr. Jens Schröter, Christoph Borbach, Max Kanderske und Prof. Dr. Benjamin Beil sind Herausgeber der Reihe. Die Herausgeber*innen der einzelnen Hefte sind renommierte Wissenschaftler*innen aus dem In- und Ausland.Technologies and especially media technologies are pervasive in modern societies. But even more omnipresent are the imaginaries of modern technologies – what technologies are thought to be capable of or what effects they are supposed to have. These imaginations reveal a lot of the political and ideological self-descriptions of societies, hence the (techno-)imaginary also functions as a kind of epistemic tool. Concepts of the imaginary therefore have experienced an increasing attention in cultural theory and the social sciences in recent years. In particular, work from political philosophy, but also approaches from science and technology studies (STS) or communication and media studies are worth mentioning here. The term "techno-imagination", coined by Vilém Flusser in the early 1990s, refers to the close interconnection of (digital) media and imaginations, whose coupling can not only be understood as a driver of future technology via fictional discourses (e.g. science fiction), but much more fundamentally also as a constitutive element of society and sociality itself, as Castoriadis has argued. In the first part of the issue several theoretical contributions add new aspects to the discussion of socio-technical imaginaries, while in the second part a workshop held in January 2022 at the CAIS in Bochum is documented, in which the case of the imaginaries of “Future Internets” was discussed

Robot Wars: US Empire and geopolitics in the robotic age

How will the robot age transform warfare? What geopolitical futures are being imagined by the US military? This article constructs a robotic futurology to examine these crucial questions. Its central concern is how robots – driven by leaps in artificial intelligence and swarming – are rewiring the spaces and logics of US empire, warfare, and geopolitics. The article begins by building a more-than-human geopolitics to de-center the role of humans in conflict and foreground a worldly understanding of robots. The article then analyzes the idea of US empire, before speculating upon how and why robots are materializing new forms of proxy war. A three-part examination of the shifting spaces of US empire then follows: (1) Swarm Wars explores the implications of miniaturized drone swarming; (2) Roboworld investigates how robots are changing US military basing strategy and producing new topological spaces of violence; and (3) The Autogenic Battle-Site reveals how autonomous robots will produce emergent, technologically event-ful sites of security and violence – revolutionizing the battlespace. The conclusion reflects on the rise of a robotic US empire and its consequences for democracy

Technology, domination and liberty: liberalism and republicanism confronted with technological change

HonorsPhilosophy, Politics, and Economics (PPE)University of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/169414/1/apsatola.pd