Drifting assemblies for persistent memory: Neuron transitions and unsupervised compensation

Change is ubiquitous in living beings. In particular, the connectome and neural representations can change. Nevertheless, behaviors and memories often persist over long times. In a standard model, associative memories are represented by assemblies of strongly interconnected neurons. For faithful storage these assemblies are assumed to consist of the same neurons over time. Here we propose a contrasting memory model with complete temporal remodeling of assemblies, based on experimentally observed changes of synapses and neural representations. The assemblies drift freely as noisy autonomous network activity and spontaneous synaptic turnover induce neuron exchange. The gradual exchange allows activity-dependent and homeostatic plasticity to conserve the representational structure and keep inputs, outputs, and assemblies consistent. This leads to persistent memory. Our findings explain recent experimental results on temporal evolution of fear memory representations and suggest that memory systems need to be understood in their completeness as individual parts may constantly change.

IoT Micro-Blockchain Fundamentals

In this paper we investigate the essential minimum functionality of the autonomous blockchain, and the minimum hardware and software required to support it in the micro-scale in the IoT world. The application of deep-blockchain operation in the lower-level activity of the IoT ecosystem, is expected to bring profound clarity and constitutes a unique challenge. Setting up and operating bit-level blockchain mechanisms on minimal IoT elements like smart switches and active sensors, mandates pushing blockchain engineering to the limits. “How deep can blockchain actually go?” “Which is the minimum Thing of the IoT world that can actually deliver autonomous blockchain functionality?” To answer, an experiment based on IoT micro-controllers was set. The “Witness Protocol” was defined to set the minimum essential micro-blockchain functionality. The protocol was developed and installed on a peer, ad-hoc, autonomous network of casual, real-life IoT micro-devices. The setup was tested, benchmarked, and evaluated in terms of computational needs, efficiency, and collective resistance against malicious attacks. The leading considerations are highlighted, and the results of the experiment are presented. Findings are intriguing and prove that fully autonomous, private micro-blockchain networks are absolutely feasible in the smart dust world, utilizing the capacities of the existing low-end IoT devices.

An Attribute-Based Cross-Domain Access Control Model for a Distributed Multiple Autonomous Network

The distributed multiple autonomous network has become the main trend of modern information systems, such as Cloud, Service-Oriented Architecture (SOA) and Internet of Things (IoT). Access control in such a heterogeneous and dynamic system has become a major information security challenge, which hinders the sharing of resources and information. In this work, we present an Attribute-Based Access Control (ABAC) model for cross-domain access control. The proposed access control model comprises a boundary control server designed to provide cross-domain access control capability. An eXtensible Access Control Markup Language (XACML) policy model-based implementation is introduced. Process and implementation show the proposed model alleviates the security risk on the domain boundary during the cross-domain access control process.

Before and After The Network

How do we think about networks under post- digital conditions? What does this imply for research? This journal issue takes as its outset, the call of the transmediale festival to “[leave] be- hind a decade marked by a backlash against the Internet and the network society” in order to re-evaluate the limits of ‘networks’. It refers to Robert Filliou’s “The Eternal Network,” an idealistic notion from the 1960s, pointing to the interconnectedness of everyday-life actions across an emerging global world at that time. This is a good reminder that network cultures exist beyond the technical reality of network culture as we now know it despite our primary identification of networks with social media and planetary computation. By drawing on the legacies of critical and autonomous network cultures, the aim was to make the limits of Internet-based networks visible but also highlight alternatives. Is there a conceivable counter-power to networks? Which alternative technological models and cultural narratives are needed to construct the principles of end-to-end communication anew? How might the critique of networks extend to non-western contexts and reflect the limits in a global perspective? To answer such complex questions, this editorial begins by reflectiing on the periodizing logic that invites us to leave behind “the backlash against the Internet.” What comes before and after the network?

Democracy Reloaded

Framed in debates about the crisis of democracy, the book analyzes one of the most influential social movements of recent times: Spain’s “Indignados” or “15-M” movement. In the wake of the global financial crisis and harsh austerity policies, 15-M movement activists occupied public squares across the country, mobilized millions of Spanish citizens, gave rise to new hybrid parties such as Podemos, and inspired pro-democracy movements around the world. Based on access to key participants in the 15-M movement and Podemos, and extensive participant observation, the book tells the story of this remarkable movement, its emergence, evolution, and impact. In so doing, it challenges some of the core arguments in social movement scholarship about the factors likely to lead to movement success. Instead, the book argues that movements organized around autonomous network logics can build and sustain strong movements in the absence of formal organizations, strong professionalized leadership, and the ability to attract external resources. The key to understanding its power lies in the shared political culture and collective identity that emerged following the occupation of Spain’s central squares. These protest camps sustained the movement by forging reciprocal ties of solidarity between diverse actors, and generating a shared set of critical master frames across a diverse set of actors and issues (e.g., housing, education, pensions, privatization of public services, corruption) that enabled the movement to effectively contest hegemonic narratives about the crisis, austerity, and democracy, influencing public debate and the political agenda.