Covert Ephemeral Communication in Named Data Networking

In the last decade, there has been a growing realization that the current Internet Protocol is reaching the limits of its senescence. This has prompted several research efforts that aim to design potential next-generation Internet architectures. Named Data Networking (NDN), an instantiation of the content-centric approach to networking, is one such effort. In contrast with IP, NDN routers maintain a significant amount of user-driven state. In this paper we investigate how to use this state for covert ephemeral communication (CEC). CEC allows two or more parties to covertly exchange ephemeral messages, i.e., messages that become unavailable after a certain amount of time. Our techniques rely only on network-layer, rather than application-layer, services. This makes our protocols robust, and communication difficult to uncover. We show that users can build high-bandwidth CECs exploiting features unique to NDN: in-network caches, routers' forwarding state and name matching rules. We assess feasibility and performance of proposed cover channels using a local setup and the official NDN testbed

Cross-linguistic Patterns in Infant Babbling

Theoretical and Experimental Linguistic

Recursion in action: An fMRI study on the generation of new hierarchical levels in motor sequences

Generation of hierarchical structures, such as the embedding of subordinate elements into larger structures, is a core feature of human cognition. Processing of hierarchies is thought to rely on lateral prefrontal cortex (PFC). However, the neural underpinnings supporting active generation of new hierarchical levels remain poorly understood. Here, we created a new motor paradigm to isolate this active generative process by means of fMRI. Participants planned and executed identical movement sequences by using different rules: a Recursive hierarchical embedding rule, generating new hierarchical levels; an Iterative rule linearly adding items to existing hierarchical levels, without generating new levels; and a Repetition condition tapping into short term memory, without a transformation rule. We found that planning involving generation of new hierarchical levels (Recursive condition vs. both Iterative and Repetition) activated a bilateral motor imagery network, including cortical and subcortical structures. No evidence was found for lateral PFC involvement in the generation of new hierarchical levels. Activity in basal ganglia persisted through execution of the motor sequences in the contrast Recursive versus Iteration, but also Repetition versus Iteration, suggesting a role of these structures in motor short term memory. These results showed that the motor network is involved in the generation of new hierarchical levels during motor sequence planning, while lateral PFC activity was neither robust nor specific. We hypothesize that lateral PFC might be important to parse hierarchical sequences in a multi-domain fashion but not to generate new hierarchical levels

ManyBabies 3: A multi-lab study of infant algebraic rule learning

The ability to learn and apply rules lies at the heart of cognition. In a seminal study, Marcus, Vijayan, Rao, and Vishton (1999) reported that seven-month-old infants learned abstract rules over syllable sequences and were able to generalize those rules to novel syllable sequences. Dozens of studies have since extended on that research using different rules, modalities, stimuli, participants (human adults and non-human animals) and experimental procedures. Yet questions remain about the robustness of Marcus et al.’s (1999) core findings, as the presence of significant learning effects has been mixed. In the current study, we aimed to address this issue by testing XX infants of a wide age range (5;0-12;0 months) in a multi-laboratory (XX laboratories) replication of the Marcus et al. (1999) study

What Pinnipeds Have to Say about Human Speech, Music, and the Evolution of Rhythm

Research on the evolution of human speech and music benefits from hypotheses and data generated in a number of disciplines. The purpose of this article is to illustrate the high relevance of pinniped research for the study of speech, musical rhythm, and their origins, bridging and complementing current research on primates and birds. We briefly discuss speech, vocal learning, and rhythm from an evolutionary and comparative perspective. We review the current state of the art on pinniped communication and behavior relevant to the evolution of human speech and music, showing interesting parallels to hypotheses on rhythmic behavior in early hominids. We suggest future research directions in terms of species to test and empirical data needed

Simple rule learning is not simple : studies on infant and adult pattern perception and production

The ability to learn rules is at the heart of the ability to learn language. This thesis is a collection of papers tackling rule learning from various perspectives and domains – including visual, auditory, and speech domains – in both infants and adults. Using both simple XYX-, XXY-, or XYY-type rules, and more complex Lindenmayer grammars, we were able to gain insights into the rule learning processes of young infants and of adults. While we were unsuccessful in attempted replications and extensions of previous studies, it was precisely these failures that helped to provide a more nuanced picture of rule learning: even the simplest type of rule learning is far from straightforward. For infants, we find evidence for a repetition bias in both the visual and speech domain that is difficult to overcome, while for adults we show that the learning environment – the task used, the instructions, types of testing stimuli – are all highly influential in determining whether a simple rule can be learned or not. Furthermore, by studying patterns found in babbling we were able to hypothesize for the first time about the parallels between production and perceptual abilities with respect to rule learning. </table

Simple rule learning is not simple : studies on infant and adult pattern perception and production

The ability to learn rules is at the heart of the ability to learn language. This thesis is a collection of papers tackling rule learning from various perspectives and domains – including visual, auditory, and speech domains – in both infants and adults. Using both simple XYX-, XXY-, or XYY-type rules, and more complex Lindenmayer grammars, we were able to gain insights into the rule learning processes of young infants and of adults. While we were unsuccessful in attempted replications and extensions of previous studies, it was precisely these failures that helped to provide a more nuanced picture of rule learning: even the simplest type of rule learning is far from straightforward. For infants, we find evidence for a repetition bias in both the visual and speech domain that is difficult to overcome, while for adults we show that the learning environment – the task used, the instructions, types of testing stimuli – are all highly influential in determining whether a simple rule can be learned or not. Furthermore, by studying patterns found in babbling we were able to hypothesize for the first time about the parallels between production and perceptual abilities with respect to rule learning. NWOTheoretical and Experimental Linguistic

Preliminary experiments on human sensitivity to rhythmic structure in a grammar with recursive self-similarity

We present the first rhythm detection experiment using a Lindenmayer grammar, a self-similar recursive grammar shown previously to be learnable by adults using speech stimuli. Results show that learners were unable to correctly accept or reject grammatical and ungrammatical strings at the group level, although five (of 40) participants were able to do so with detailed instructions before the exposure phase