FedComm: Federated Learning as a Medium for Covert Communication

Proposed as a solution to mitigate the privacy implications related to the adoption of deep learning, Federated Learning (FL) enables large numbers of participants to successfully train deep neural networks without having to reveal the actual private training data. To date, a substantial amount of research has investigated the security and privacy properties of FL, resulting in a plethora of innovative attack and defense strategies. This paper thoroughly investigates the communication capabilities of an FL scheme. In particular, we show that a party involved in the FL learning process can use FL as a covert communication medium to send an arbitrary message. We introduce FedComm, a novel multi-system covert-communication technique that enables robust sharing and transfer of targeted payloads within the FL framework. Our extensive theoretical and empirical evaluations show that FedComm provides a stealthy communication channel, with minimal disruptions to the training process. Our experiments show that FedComm successfully delivers 100% of a payload in the order of kilobits before the FL procedure converges. Our evaluation also shows that FedComm is independent of the application domain and the neural network architecture used by the underlying FL scheme.Comment: 18 page

Internet of Underwater Things and Big Marine Data Analytics -- A Comprehensive Survey

The Internet of Underwater Things (IoUT) is an emerging communication ecosystem developed for connecting underwater objects in maritime and underwater environments. The IoUT technology is intricately linked with intelligent boats and ships, smart shores and oceans, automatic marine transportations, positioning and navigation, underwater exploration, disaster prediction and prevention, as well as with intelligent monitoring and security. The IoUT has an influence at various scales ranging from a small scientific observatory, to a midsized harbor, and to covering global oceanic trade. The network architecture of IoUT is intrinsically heterogeneous and should be sufficiently resilient to operate in harsh environments. This creates major challenges in terms of underwater communications, whilst relying on limited energy resources. Additionally, the volume, velocity, and variety of data produced by sensors, hydrophones, and cameras in IoUT is enormous, giving rise to the concept of Big Marine Data (BMD), which has its own processing challenges. Hence, conventional data processing techniques will falter, and bespoke Machine Learning (ML) solutions have to be employed for automatically learning the specific BMD behavior and features facilitating knowledge extraction and decision support. The motivation of this paper is to comprehensively survey the IoUT, BMD, and their synthesis. It also aims for exploring the nexus of BMD with ML. We set out from underwater data collection and then discuss the family of IoUT data communication techniques with an emphasis on the state-of-the-art research challenges. We then review the suite of ML solutions suitable for BMD handling and analytics. We treat the subject deductively from an educational perspective, critically appraising the material surveyed.Comment: 54 pages, 11 figures, 19 tables, IEEE Communications Surveys & Tutorials, peer-reviewed academic journa

Spatial Attention, Precision, and Bayesian Inference: A Study of Saccadic Response Speed

Inferring the environment's statistical structure and adapting behavior accordingly is a fundamental modus operandi of the brain. A simple form of this faculty based on spatial attentional orienting can be studied with Posner's location-cueing paradigm in which a cue indicates the target location with a known probability. The present study focuses on a more complex version of this task, where probabilistic context (percentage of cue validity) changes unpredictably over time, thereby creating a volatile environment. Saccadic response speed (RS) was recorded in 15 subjects and used to estimate subject-specific parameters of a Bayesian learning scheme modeling the subjects' trial-by-trial updates of beliefs. Different response models—specifying how computational states translate into observable behavior—were compared using Bayesian model selection. Saccadic RS was most plausibly explained as a function of the precision of the belief about the causes of sensory input. This finding is in accordance with current Bayesian theories of brain function, and specifically with the proposal that spatial attention is mediated by a precision-dependent gain modulation of sensory input. Our results provide empirical support for precision-dependent changes in beliefs about saccade target locations and motivate future neuroimaging and neuropharmacological studies of how Bayesian inference may determine spatial attentio

Spatial attention, precision, and Bayesian inference: a study of saccadic response speed

Inferring the environment's statistical structure and adapting behavior accordingly is a fundamental modus operandi of the brain. A simple form of this faculty based on spatial attentional orienting can be studied with Posner's location-cueing paradigm in which a cue indicates the target location with a known probability. The present study focuses on a more complex version of this task, where probabilistic context (percentage of cue validity) changes unpredictably over time, thereby creating a volatile environment. Saccadic response speed (RS) was recorded in 15 subjects and used to estimate subject-specific parameters of a Bayesian learning scheme modeling the subjects' trial-by-trial updates of beliefs. Different response models-specifying how computational states translate into observable behavior-were compared using Bayesian model selection. Saccadic RS was most plausibly explained as a function of the precision of the belief about the causes of sensory input. This finding is in accordance with current Bayesian theories of brain function, and specifically with the proposal that spatial attention is mediated by a precision-dependent gain modulation of sensory input. Our results provide empirical support for precision-dependent changes in beliefs about saccade target locations and motivate future neuroimaging and neuropharmacological studies of how Bayesian inference may determine spatial attention. © The Author 2013. Published by Oxford University Pres

Space networks: towards hodological space design for urban man, starting with a cognitive / perceptual notation

The main purpose of this thesis on Space Networks is to make a contribution to urban design0A iming at the level of the urban designer's or architect's prestructure (after the site has been seen,and before any plan/section/elevation drawings are done),it is meant for those designers involved in res earth themselves,and who accept the idea that they are,in a way, the first users of what they design.The additional purpose is to provide a sociological, psychological,and spatial scale context for dynamic design. Space is looked upon as a network.Where the space-of-possible- movement (taking the shortest/most agreable/most energy demanding/etc way, depending whether you are in a hurry/strolling/exercising yourself/etc respectively) is called Hodological Space.Movement --through-space-with-intention is used as a generator for design.We start with a proposed cognitive/perceptual notation of four spatial conceptual components: First with Section-Perspective (by which we do away with the facades,and considering the building not in isolation ---in the form of an endless isometric). Then the Tube (employing the anticipation,cognitively,of the projecting brain of man for his path of action),and also the Sequential (progressive sequences) and Binary (visual contrasts of 'wholes')- -these perceived as man moves through his Hodological space.There are six Chapters and an Appendix.Chapter I is introductory,and its three parts are extended in the Chapters that follow: Movement Through Space in Chapters 3 and 4,Space- Movement Notation in Chapters 5 and 6,and the Intended Fieldwork And Pilot Questionnaires in the Appendix.In Chapter 2 the clarifying distinction is made between space for activity and space for profit.Which issue,far from a refinement,shifts the problem back to where it belongs: the society values --of which the designer himself partakes. ln Chapter 3 man is not seen from the stimulus -response,but the cognitive psychology side: not passive,but projecting his intentions into his environment --and if it goes a bit too far in that direction it is in compensation for the opposite view.ln Chapter 4 a comprehensive classification of space,into Hodological,Ambient,and Personal,is made for the designer's understanding and use.All three spaces are more fundamental to him than Euclidean space which is significant only in relation to them.ln Chapter 5 the four-component Notation is a rticulated into the cognitive /perceptual anthropological model of cognitive anticipation (see Tube),and perceptual experience (see Sequential and Binary),together with a comparative discussion of the other notatorst work,ranging between the scales of landscape design (Halprin) and microspace behaviour (Hall),In Chapter 6 the proposition of using the present anthropological model of a cognitive /perceptual notation of design-for-movement has been taken up as a process employed in experimental design.The program of designing for Hodological space --as well as for Ambient space which accompanies progress through Hodological space --links psychological research to design for the pedestrian

\u3cem\u3eWork\u3c/em\u3e 2006/2007

WORK is an annual publication of the Department of Architecture that documents student work in design studios and courses in the Master of Architecture and Post-Professional programs, as well as events, faculty news and student awards. It also includes abstracts of PhD dissertations defended that year. It provides an opportunity to explore the creative work of our students and is a permanent record of work in the Department

From systematic semiotic modelling to pseudointentional reference

Societies as open social systems work through semiotic modelling systems. We view their relevance for shaping primary and secondary needs, as well as metaneeds that are conditioned in social systems. Through conditioning in socialization, semiotic reality can be naturalized up to a level where we can start speaking about not only unconscious, but also unintentional semiosic activity. By that, the very realm of indexicality will be questioned. If indexicality is conjoined with unintended referentiality, then unintentional semiosis means the blurring and fusion of realities far beyond the so-called simulacral semiotic spaces. It is especially acute in the context of the development of technological availabilities where the physical, the semiotic, and the purely virtual reality merge. That quite novel phenomenon is exemplified by semiotic insularization. What follows is that it is hard to define the research object, for the subject is fading away, the real and the virtual are intermingling also in terms of their inhabitants (biological humans, computer users, avatars, virtual identities). Thus the pragmatic dimension of semiotics is gradually becoming lost. Also, the referential reality is moving farther from the informational space created and represented in “traditional” discursive flows, rather becoming based on pseudoreferential clues of meaning making

A Bricolage of Critical Hermeneutics, Abductive Reasoning, and Action Research for Advancing Humanistic Values through Organization Development Practice

This is an emergent and auto-ethnographic study to find ways for the practice of organization development (OD) to recover and sustain humanism in the workplace. It begins with a literature review hermeneutically exploring the history and relevance of three modes of inquiry—hermeneutics, abductive reasoning, and action research—paratactically, which is to say, separately without overlap or reference to each other—to future OD practice. These three modes were selected from an extended literature search for non-reductive modes of inquiry that could address the range of human interests and workplace disease as I understand them. I combined my strong background reading on hermeneutics with the abductive reasoning of C. S. Peirce as two of the modes for review and also reflexively as part of my own methodology. The third mode, action research, is borrowed from the work of Kurt Lewin and his tradition in OD, known for its humanistic and democratic aims. Also included in the literature review is a report on the some of the more salient challenges and opportunities currently confronting the practice of organization development (OD) to provide a context for practical expression of my emerging discoveries. Following the literature review, I hermeneutically surfaced submerged, tacit (hidden-from-consciousness) generative connections from the confluence (flowing together) of the three modes, as they abductively emerged from within my expanding hermeneutic experience (known as a horizon) with the literature review. I then interpret the tacit relevance of that confluence through my life experience, for illuminating those OD challenges and opportunities. Finally this study integrates a sequence of critical hermeneutic and abductive processes in a participatory action research (PAR) pathway leading to plateaus of discovery and renewal through facilitation by humanistically oriented OD praxis. I conclude with five abduced interventions hypothetically drawn from personal case studies. My audience are OD practitioners inclined to develop wholistic humanism in the workplace through facilitative immersion with small groups and micro-cultures. Here they may find enlarged conceptual frames to reconceptualize OD, engage clients in transformative dialogue, and create actionable knowledge in their practice

Securing voice communications using audio steganography

Although authentication of users of digital voice-based systems has been addressed by much research and many commercially available products, there are very few that perform well in terms of both usability and security in the audio domain. In addition, the use of voice biometrics has been shown to have limitations and relatively poor performance when compared to other authentication methods. We propose using audio steganography as a method of placing authentication key material into sound, such that an authentication factor can be achieved within an audio channel to supplement other methods, thus providing a multi factor authentication opportunity that retains the usability associated with voice channels. In this research we outline the challenges and threats to audio and voice-based systems in the form of an original threat model focusing on audio and voice-based systems, we outline a novel architectural model that utilises audio steganography to mitigate the threats in various authentication scenarios and finally, we conduct experimentation into hiding authentication materials into an audible sound. The experimentation focused on creating and testing a new steganographic technique which is robust to noise, resilient to steganalysis and has sufficient capacity to hold cryptographic material such as a 2048 bit RSA key in a short audio music clip of just a few seconds achieving a signal to noise ratio of over 70 dB in some scenarios. The method developed was seen to be very robust using digital transmission which has applications beyond this research. With acoustic transmission, despite the progress demonstrated in this research some challenges remain to ensure the approach achieves its full potential in noisy real-world applications and therefore the future research direction required is outlined and discussed