Optimal Message-Passing with Noisy Beeps

Beeping models are models for networks of weak devices, such as sensor networks or biological networks. In these networks, nodes are allowed to communicate only via emitting beeps: unary pulses of energy. Listening nodes only the capability of carrier sensing: they can only distinguish between the presence or absence of a beep, but receive no other information. The noisy beeping model further assumes listening nodes may be disrupted by random noise. Despite this extremely restrictive communication model, it transpires that complex distributed tasks can still be performed by such networks. In this paper we provide an optimal procedure for simulating general message passing in the beeping and noisy beeping models. We show that a round of Broadcast CONGEST can be simulated in O(Δ log n) round of the noisy (or noiseless) beeping model, and a round of CONGEST can be simulated in O(Δ2 log n) rounds (where Δ is the maximum degree of the network). We also prove lower bounds demonstrating that no simulation can use asymptotically fewer rounds. This allows a host of graph algorithms to be efficiently implemented in beeping models. As an example, we present an O(log n)-round Broadcast CONGEST algorithm for maximal matching, which, when simulated using our method, immediately implies a near-optimal O(Δ log2 n)-round maximal matching algorithm in the noisy beeping model

Direction of visual apparent motion driven solely by timing of a static sound

In temporal ventriloquism, auditory events can illusorily attract perceived timing of a visual onset [1,2,3]. We investigated whether timing of a static sound can also influence spatio-temporal processing of visual apparent motion, induced here by visual bars alternating between opposite hemifields. Perceived direction typically depends on the relative interval in timing between visual left-right and right-left flashes (e.g., rightwards motion dominating when left-to-right interflash intervals are shortest [4]). In our new multisensory condition, interflash intervals were equal, but auditory beeps could slightly lag the right flash, yet slightly lead the left flash, or vice versa. This auditory timing strongly influenced perceived visual motion direction, despite providing no spatial auditory motion signal whatsoever. Moreover, prolonged adaptation to such auditorily driven apparent motion produced a robust visual motion aftereffect in the opposite direction, when measured in subsequent silence. Control experiments argued against accounts in terms of possible auditory grouping, or possible attention capture. We suggest that the motion arises because the sounds change perceived visual timing, as we separately confirmed. Our results provide a new demonstration of multisensory influences on sensory-specific perception [5], with timing of a static sound influencing spatio-temporal processing of visual motion direction

Noisy Beeping Networks

We introduce noisy beeping networks, where nodes have limited communication capabilities, namely, they can only emit energy or sense the channel for energy. Furthermore, imperfections may cause devices to malfunction with some fixed probability when sensing the channel, which amounts to deducing a noisy received transmission. Such noisy networks have implications for ultra-lightweight sensor networks and biological systems. We show how to compute tasks in a noise-resilient manner over noisy beeping networks of arbitrary structure. In particular, we transform any algorithm that assumes a noiseless beeping network (of size $n$) into a noise-resilient version while incurring a multiplicative overhead of only $O(\log n)$ in its round complexity, with high probability. We show that our coding is optimal for some tasks, such as node-coloring of a clique. We further show how to simulate a large family of algorithms designed for distributed networks in the CONGEST($B$) model over a noisy beeping network. The simulation succeeds with high probability and incurs an asymptotic multiplicative overhead of $O(B\cdot \Delta \cdot \min(n,\Delta^2))$ in the round complexity, where $\Delta$ is the maximal degree of the network. The overhead is tight for certain graphs, e.g., a clique. Further, this simulation implies a constant overhead coding for constant-degree networks

TRUST IN TRANSITION: CROSS COUNTRY AND FIRM EVIDENCE

This paper uses data from a large survey of firms across 26 transition countries to examine the determinants of trust in the transition process. We first introduce a new measure of trust between firms: the level of prepayment demanded by suppliers from their customers in advance of delivery. Using this new measure, we confirm earlier findings that trust is higher where firms have confidence in third party enforcement through the legal system. However, the fairness and honesty of the courts are a more important determinant of interfirm trust than are the courts’ efficiency or ability to enforce decisions. We then examine the role of business networks in building trust and find that networks based around personal ties – family and friends – and business associations actively promote the development of trust, while business networks based on enterprise insiders and government agencies do not. Finally, we find that country-level effects are significantly more important determinants of interfirm trust than are firm-level effects.http://deepblue.lib.umich.edu/bitstream/2027.42/40026/3/wp640.pd

Shifts of criteria or neural timing? The assumptions underlying timing perception studies

In timing perception studies, the timing of one event is usually manipulated relative to another, and participants are asked to judge if the two events were synchronous, or to judge which of the two events occurred first. Responses are analyzed to determine a measure of central tendency, which is taken as an estimate of the timing at which the two events are perceptually synchronous. When these estimates do not coincide with physical synchrony, it is often assumed that the sensory signals are asynchronous, as though the transfer of information concerning one input has been accelerated or decelerated relative to the other. Here we show that, while this is a viable interpretation, it is equally plausible that such effects are driven by shifts in the criteria used to differentiate simultaneous from asynchronous inputs. Our analyses expose important ambiguities concerning the interpretation of simultaneity judgement data, which have hitherto been underappreciated

Does Consciousness Collapse the Wave Function

A conceptual replication of the Hall-experiment to test the 'subjective reduction' interpretation of the measurement problem in Quantum Physics is reported. Two improvements are introduced. First the delay between pre-observation and final observation of the same quantum event is increased from a few microseconds in the original experiment to 1 second in this replication. Second, rather than using the observers conscious response as the dependent variable, we use the early brain responses as measured by EEG. These early responses cover a period where the observer is not yet conscious of the quantum event. Results support the 'subjective reduction' hypothesis because significant differences between the brain responses of the final observer are found dependent upon the pre-observer looking or not looking at the quantum event (exact binomial p < 0.02). Alternative 'normal' explanations are discussed and rejected. It is concluded that the present results do justify further research along these lines.Comment: 11 pages, 4 figures, 1 tabl

Convergence in Institutions and Market Outcomes: Cross-Country and Time-Series Evidence from the BEEPS Surveys in Transition Economies

This paper uses the BEEPS firm-level data to study the process of convergence of transition countries with developed market economies. The primary focus of the study is on competition and market structure, finance and the structure of lending to firms, and how firms respond to the economic environment by restructuring; we are able to do this because the BEEPS cover thousands of firms from virtually all transition countries over a long time period (1996-99 through 2002-05), as well firms from developed market economies, thus providing a set of natural benchmarks. We find substantial evidence of convergence of transition countries with developed market economies in a number of dimensions. The pattern of growth at the country, sectoral and firm level shows rapid growth of the new private sector and of the micro- and small-firm sectors, with the size distribution of firms moving towards the pattern observed in the BEEPS surveys of developed market economies. Our interpretation of the evidence on competition is that there is an initial move by firms into niches to exploit local market power, and later in transition entry and domestic competitive pressure increases. In finance, the increasing reliance on retained earnings in transition countries reflects a maturation of the sector as new firms come to rely less on informal and family sources of finance. The scale of restructuring and innovation activity is as high or higher in transition economies as in developed market economies. Interestingly, we find evidence of an inverse-U shape pattern, with the peak of restructuring activity taking place in 2002, the middle of the period analyzed. Throughout, the regional patterns suggest greater convergence in the transition countries that joined the European Union in 2004 than in the other, lower-income transition economies.transition, convergence, market structure, competition, enterprise finance, enterprise restructuring

Trust in Transition: Cross-country and Firm Evidence

This paper uses data from a large survey of firms across 26 transition countries to examine the determinants of trust in the transition process. We first introduce a new measure of trust between firms: the level of prepayment demanded by suppliers from their customers in advance of delivery. Using this new measure, we confirm earlier findings that trust is higher where firms have confidence in third party enforcement through the legal system. However, the fairness and honesty of the courts are more important determinants of inter-firm trust than the courts’ efficiency or ability to enforce decisions. We then examine the role of business networks in building trust and find that networks based around personal ties – family and friends – and business associations actively promote the development of trust, while business networks based on enterprise insiders and government agencies do not. Finally, we find that country-level effects are significantly more important determinants of inter-firm trust than firm-level effects.transition, trust, prepayment, courts, business networks

Enhanced visualisation of dance performance from automatically synchronised multimodal recordings

The Huawei/3DLife Grand Challenge Dataset provides multimodal recordings of Salsa dancing, consisting of audiovisual streams along with depth maps and inertial measurements. In this paper, we propose a system for augmented reality-based evaluations of Salsa dancer performances. An essential step for such a system is the automatic temporal synchronisation of the multiple modalities captured from different sensors, for which we propose efficient solutions. Furthermore, we contribute modules for the automatic analysis of dance performances and present an original software application, specifically designed for the evaluation scenario considered, which enables an enhanced dance visualisation experience, through the augmentation of the original media with the results of our automatic analyses