Miracle-dz/UniFAR-FTUs huggingface dataset:
Spatial Organization of Neuronal Population Responses in Layer 2/3 of Rat Barrel Cortex

Individual pyramidal neurons of neocortex show sparse and variable responses to sensory stimuli in vivo. It has remained unclear how this variability extends to population responses on a trial-to-trial basis. Here, we characterized single-neuron and population responses to whisker stimulation in layer 2/3 (L2/3) of identified columns in rat barrel cortex using in vivo two-photon calcium imaging. Optical detection of single action potentials from evoked calcium transients revealed low spontaneous firing rates (0.25 Hz), variable response probabilities (range, 0–0.5; mean, 0.2 inside barrel column), and weak angular tuning of L2/3 neurons. On average, both the single-neuron response probability and the percentage of the local population activated were higher in the barrel column than above septa or in neighboring columns. Within the barrel column, mean response probability was highest in the center (0.4) and declined toward the barrel border. Neuronal pairs showed correlations in both spontaneous and sensory-evoked activity that depended on the location of the neurons. Correlation decreased with increasing distance between neurons and, for neuronal pairs the same distance apart, with distance of the pair from the barrel column center. Although neurons are therefore not activated independently from each other, we did not observe precisely repeating spatial activation patterns. Instead, population responses showed large trial-to-trial variability. Nevertheless, the accuracy of decoding stimulus onset times from local population activity increased with population size and depended on anatomical location. We conclude that, despite their sparseness and variability, L2/3 population responses show a clear spatial organization on the columnar scale.
Fault tolerant graphs, perfect hash functions and disjoint paths

Given a graph G on n nodes the authors say that a graph T on n + k nodes is a k-fault tolerant version of G, if one can embed G in any n node induced subgraph of T. Thus T can sustain k faults and still emulate G without any performance degradation. They show that for a wide range of values of n, k and d, for any graph on n nodes with maximum degree d there is a k-fault tolerant graph with maximum degree O(kd). They provide lower bounds as well: there are graphs G with maximum degree d such that any k-fault tolerant version of them has maximum degree at least Omega (d square root k). <<ETX>>
Performance Analysis of Queueing Networks via Robust Optimization

Performance analysis of queueing networks is one of the most challenging areas of queueing theory. Barring very specialized models such as product-form type queueing networks, there exist very few results that provide provable nonasymptotic upper and lower bounds on key performance measures. In this paper we propose a new performance analysis method, which is based on the robust optimization. The basic premise of our approach is as follows: rather than assuming that the stochastic primitives of a queueing model satisfy certain probability laws---such as i.i. d. interarrival and service times distributions---we assume that the underlying primitives are deterministic and satisfy the implications of such probability laws. These implications take the form of simple linear constraints, namely, those motivated by the law of the iterated logarithm (LIL). Using this approach we are able to obtain performance bounds on some key performance measures. Furthermore, these performance bounds imply similar bounds in the underlying stochastic queueing models. We demonstrate our approach on two types of queueing networks: (a) tandem single-class queueing network and (b) multiclass single-server queueing network. In both cases, using the proposed robust optimization approach, we are able to obtain explicit upper bounds on some steady-state performance measures. For example, for the case of TSC system we obtain a bound of the form C(1-ρ)-1 ln ln((1-ρ)-1) on the expected steady-state sojourn time, where C is an explicit constant and ρ is the bottleneck traffic intensity. This qualitatively agrees with the correct heavy traffic scaling of this performance measure up to the ln ln((1-ρ)-1) correction factor.
Towards eliminating configuration errors in cyber infrastructure

It is well-documented that configuration errors account for 50% to 80% of downtime and vulnerabilities in cyber infrastructure. The ConfigAssure suite of tools has been developed to help eliminate these errors. These tools are for requirement specification, configuration synthesis, diagnosis and repair, verification, reconfiguration planning and visualization. These tools are being made available as a web service that is demonstrated.
Effect of Papillary Muscles and Trabeculae on Left Ventricular Measurement Using Cardiovascular Magnetic Resonance Imaging in Patients with Hypertrophic Cardiomyopathy

Objective To evaluate the influence of papillary muscles and trabeculae on left ventricular (LV) cardiovascular magnetic resonance (CMR) analysis using three methods of cavity delineation (classic or modified inclusion methods, and the exclusion method) in patients with hypertrophic cardiomyopathy (HCM). Materials and Methods This retrospective study included 20 consecutive HCM patients who underwent 1.5-T CMR imaging with short-axis cine stacks of the entire LV. LV measurements were performed using three different methods of manual cavity delineation of the endocardial and epicardial contours: method A, presumed endocardial boundary as seen on short-axis cine images; method B, including solely the cavity and closely adjacent trabeculae; or method C, excluding papillary muscles and trabeculae. Ascending aorta forward flow was measured as reference for LV-stroke volume (SV). Interobserver reproducibility was assessed using intraclass correlation coefficients. Results Method A showed larger end-diastole and end-systole volumes (largest percentage differences of 25% and 68%, respectively, p < 0.05), compared with method C. The ejection fraction was 55.7 ± 6.9% for method A, 68.6 ± 8.4% for B, and 71.7 ± 7.0% for C (p < 0.001). Mean mass was also significantly different: 164.6 ± 47.4 g for A, 176.5 ± 50.5 g for B, and 199.6 ± 53.2 g for C (p < 0.001). LV-SV error was largest with method B (p < 0.001). No difference in interobserver agreement was observed (p > 0.05). Conclusion In HCM patients, LV measurements are strikingly different dependent on whether papillary muscles and trabeculae are included or excluded. Therefore, a consistent method of LV cavity delineation may be crucial during longitudinal follow-up to avoid misinterpretation and erroneous clinical decision-making.
The influence of near threshold visual distractors 1 on perceptual detection and reaching movements

28 Providing evidence against a dissociation between conscious vision for 29 perception and unconscious vision for action, recent studies have suggested that 30 perceptual and motor decisions are based on a unique signal but distinct decisional 31 thresholds. The aim of the present study was to provide a direct test of this assumption 32 in a perceptual-motor dual task involving arm movements. In 300 trials, 10 participants 33 performed speeded pointing movements towards a highly visible target located at 10° 34 from the fixation point and ±45° from the body midline. The target was preceded by one 35 or two close to threshold distractor(s) (80ms SOA) presented ±30° according to the 36 target location. After each pointing movement participants judged whether the 37 distractor was present or not on either side of the target. Results showed a robust 38 reaction time facilitation effect and a deviation towards the distractor when the 39 distractor was both present and consciously perceived (Hit). A small reaction time 40 facilitation was also observed when two distractors were physically present but 41 undetected (Double-Miss) – this facilitation being highly correlated with the physical 42 contrast of the distractors. These results are compatible with the theory proposing that 43 perceptual and motor decisions are based on a common signal but emerge from a 44 contrast dependent fixed threshold for motor responses and a variable context 45 dependent criterion for perceptual responses. This paper thus extends to arm 46 movement control previous findings related to oculomotor control.
Charitable Conservatism, Poverty Radicalism and Good Old Fashioned Inequality Aversion

In his Presidential Address to the European Economic Association, Tony Atkinson introduced the idea of a “Charitable Conservatism” position in public policy, which “exhibits a degree of concern for the poor, but this is the limit of the redistributional concern and there is indifference with respect to transfers above the poverty line. ” This contrasts with the perspective of poverty indices, which give zero weight to those above the poverty line, which we call “Poverty Radicalism,” and with standard “Inequality Aversion” where the weights decline smoothly as we move up the income scale. The object of this paper is, first, to clarify the interrelationships between Charitable Conservatism, Poverty Radicalism and Inequality Aversion. We do this by showing how the patterns of welfare weights to which each of these gives rise are related to each other. Secondly, we are concerned to demonstrate the implications of these different views for optimal income taxation. In terms of levels and patterns of marginal tax rates, we show that Charitable Conservatism and Poverty Radicalism are on a continuum, and by choice of low or high Inequality Aversion one can approximate either outcome fairly well.
SOCIALLY SITUATED LIFE-LIKE AGENTS : IF IT MAKES YOU HAPPY THEN IT CAN ' T BE THAT BAD ? !

This paper discusses the psychological basis of believ-ability. Story-telling, empathy, historical grounding (autobiography), andècological grounding' in an environment are identiied as factors which are relevant to the way how humans understand the (social) world. It is suggested that applying such criteria to the construction of artiicial lifelike agents is more relevant than trying to achieve realism by imitating the appearance of humans or other animals in great detail.
Flipper-driven terrestrial locomotion of a sea turtle-inspired robot

To discover principles of flipper-based terrestrial locomotion we study the mechanics of a hatchling sea turtle-inspired robot, FlipperBot (FBot), during quasi-static movement on granular media. FBot implements a symmetric gait using two servo-motor-driven front limbs with flat-plate flippers and either freely rotating or fixed wrist joints. For a range of gaits, FBot moves with a constant step length. However, for gaits with sufficiently shallow flipper penetration or sufficiently large stroke, per step displacement decreases with each successive step resulting in failure (zero forward displacement) within a few steps. For the fixed wrist, failure occurs when FBot interacts with ground disturbed during previous steps, and measurements reveal that flipper generated forces decrease as per step displacement decreases. The biologically inspired free wrist is less prone to failure, but slip-induced failure can still occur if FBot pitches forward and drives its leading edge into the substrate. In the constant step length regime, kinematic and force-based models accurately predict FBot's motion for free and fixed wrist configurations, respectively. When combined with independent force measurements, models and experiments provide insight into how disturbed ground leads to locomotory failure and help explain differences in hatchling sea turtle performance.
A recursive generalized sidelobe canceler for multichannel blind speech dereverberation

In this paper, we propose a generalized sidelobe canceler for multichannel blind speech dereverberation, which relies on recursive estimation of posterior distributions on the unknown acoustic channels and the adaptive interference canceler (AIC). Contrary to conventional design approaches where a fixed beamformer is employed, we consider a marginalized maximum-likelihood equalizer that is driven by the channel posterior estimator. It is shown that the first moment of the inferred channel posterior can also serve as a representation of an adaptive blocking matrix (ABM). Using the output of the blocking matrix, we estimate the AIC posterior to minimize the residual reverberation in the equalized signal. We demonstrate the efficacy of our approach by evaluating the algorithm in different degrees of observation noise and varying reverberation times.
A 260 GHz fully integrated CMOS transceiver for wireless chip-to-chip communication

A fully integrated 260GHz OOK transceiver is demonstrated in 65nm CMOS. Communication at 10Gb/s has been verified over a range of 40 mm. The Tx/Rx dual on-chip antenna array is implemented with half-width leaky wave antennas. Each Tx consists of a quadrupler driven by a class-D-1 PA with a distributed OOK modulator, and outputs +5 dBm of EIRP. The Rx uses a double balanced mixer to down-convert to a V-band IF signal that is amplified with a wideband IF driver and demoduated on-chip.
A Route to Magnetic Field Reversals: An Example of an ABC-Forced Nonlinear Dynamo

We are investigating numerically the nonlinear behaviour of a space-periodic MHD system with ABC forcing. Most computations are performed for magnetic Reynolds numbers increasing from 0 to 60 and a fixed kinematic Reynolds number, small enough for the trivial solution with a zero magnetic field to be stable to velocity perturbations. At the critical magnetic Reynolds number for the onset of instability of the trivial solution the dominant eigenvalue of the kinematic dynamo problem is real. In agreement with the bifurcation theory new steady states with non-vanishing magnetic field appear in this bifurcation. Subsequent bifurcations are investigated. A regime is detected, where chaotic variations of the magnetic field orientation (analogous to magnetic field reversals) are observed in the temporal evolution of the system.
A parametric model approach for quantification of short term QT variability uncorrelated with heart rate variability

In this work we propose to assess the relation between HRV and QTV measured by an automatic delineator. A low order linear autoregressive model on RR versus QT interactions was used to explore short term relations and quantify the fractions of QTV correlated and not correlated with HRV. Power spectral density measures were estimated from the total QTV and from the two separated fractions using the proposed model. Simulated RR and QT series were used to quantify the error bounds associated to the method performance. ECG records of young normal subjects were processed to obtain the RR and QT series. The high QTV fraction not correlated with RR found in these records (over 40% in 98% of the segments) indicates that an important part of QTV can be driven by other factors rather than by heart rate, and may contain complementary information.
Multi-Modal Tracking of Interacting Targets Using Gaussian Approximations

We introduce a modular tracker architecture that combines the advantages of several simple and rapidly performing tracking algorithms. Robust tracking is facilitated by fra merate or near-frame-rate processing. A Kalman filter is used to integrate tracking results across detection modules and over time. Processing regions are smoothly localized by weighting with a Gaussian that is dimensioned according to the target sizes and uncertainties estimated by the Kalman filter. From this Gaussian mask, Gaussian approximations of known nearby targets are subtracted to allow individual tracking of interacting targets, that can be merged and spli t based on Mahalanobis distances and a robust version of connected components. The result is an adaptive tracker that can robustly track at video frame rates several targets , each of which corresponds to one or more individual objects. Its performance degrades gracefully with increased system load.
Model-Based Robust Control Design for Magnetostrictive Transducers Operating in Hysteretic and Nonlinear Regimes

This paper addresses the development of robust control designs for high-performance smart material transducers operating in nonlinear and hysteretic regimes. While developed in the context of a magnetostrictive transducer used for high-speed, high-accuracy milling, the resulting model-based control techniques can be directly extended to systems utilizing piezoceramic or shape memory alloy compounds due to the unified nature of models used to quantify hysteresis and nonlinearities inherent to all of these materials. When developing models and corresponding inverse filters or compensators, significant emphasis is placed on the utilization of the material's physics to provide the accuracy and efficiency required for real-time implementation of resulting model-based control designs. In the material models, this is achieved by combining energy analysis with stochastic homogenization techniques, whereas the efficiency of forward algorithms is combined with monotonicity properties of the material behavior to provide highly efficient inverse algorithms. These inverse filters are then incorporated in H2 and Hinfin theory to provide robust control algorithms capable of providing high-accuracy tracking even though the actuators are operating in nonlinear and hysteretic regimes. Through numerical examples, it is illustrated that the robust designs incorporating inverse compensators can achieve the required tracking tolerance of 1-2 mum for the motivating milling application, whereas robust designs which treat the uncompensated hysteresis and nonlinearities as unmodeled disturbances cannot achieve design specifications
Optimizing expected path lengths with ant colony optimization using fitness proportional update

We study the behavior of a Max-Min Ant System (MMAS) on the stochastic single-destination shortest path (SDSP) problem. Two previous papers already analyzed this setting for two slightly different MMAS algorithms, where the pheromone update fitness-independently rewards edges of the best-so-far solution. The first paper showed that, when the best-so-far solution is not reevaluated and the stochastic nature of the edge weights is due to noise, the MMAS will find a tree of edges successfully and efficiently identify a shortest path tree with minimal noise-free weights. The second paper used reevaluation of the best-so-far solution and showed that the MMAS finds paths which beat any other path in direct comparisons, if existent. For both results, for some random variables, this corresponds to a tree with minimal expected weights. In this work we analyze a variant of MMAS that works with fitness-proportional update on stochastic-weight graphs with arbitrary random edge weights from [0,1]. For δ such that any suboptimal path is worse by at least δ than an optimal path, then, with suitable parameters, the graph will be optimized after O(n3 ln n/δ over δ3 iterations (in expectation). In order to prove the above result, the multiplicative and the variable drift theorem are adapted to continuous search spaces.
Top-down definition of Network Centric Operating System features

Thesis Network (and grid, if we view grids as networks with specific middleware on top of the component processing node operating systems) programming is an hard task due to the necessity of taking into account network latencies and faults, dynamic node availability and load, performance/efficiency requirements and constrains, etc. Figure 1 Factorizing our long experience in the field of high performance, structured parallel programming models for workstation clusters/networks and grids, we propose to derive a sort of reduced instruction set to be included in a network centric operating system to support layered responsibility in the development of network/grid applications. We claim that the basic features needed to run grid applications is only a small set of features, including efficient data/file transfer, resource inventory/discovery, remote commanding, accounting and communication. We also claim that these few mechanisms can be exploited using a mix of static techniques (compiler based) and dynamic techniques (run time system based) to implement the programming model at hand, much in the sense the RISC processor instructions was exploited to implement completely different high level programming languages [1][2]. Therefore we propose to study an approach like the one summarized in Figure 1. Typical, effective grid applications should be studied to carefully understand which is the set of grid mechanisms exploited. In the meanwhile, typical operating systems have to be analyzed to understand which mechanisms suitable to support grid programming they provide and which is their efficiency. Then, carefully analyzing the results achieved in these two steps, the set of mechanisms actually needed in a network centric operating system can be derived. Such mechanisms can be added to existing operating systems or a new operating system including them can be designed. Whether the former or the latter choice is to be taken, it depends on the number of mechanisms needed and in the cost involved in their introduction in (one of the) existing operating systems. Such an approach should guarantee that we do not incur the risk of fixing too many features in the operating system. We have experience in the GRID.it project that supports this approach. In this project we developed a high level, structured, parallel grid-programming environment that is compiled on top of existing Globus middleware. The features of both Globus and underlying operating system actually used to run the programs developed using this environment are actually a very small set of mechanisms. Almost no one of the …
Important Moments in Systems and Control

The moment problem matured from its various special forms in the late 19th and early 20th centuries to a general class of problems that continues to exert profound influence on the development of analysis and its applications to a wide variety of fields. In particular, the theory of systems and control is no exception, where the applications have historically been to circuit theory, optimal control, robust control, signal processing, spectral estimation, stochastic realization theory, and the use of the moments of a probability density. Many of these applications are also still works in progress. In this paper, we consider the generalized moment problem, expressed in terms of a basis of a finite-dimensional subspace P of the Banach space $C[a,b]$ and a “positive” sequence $c$, but with a new wrinkle inspired by the applications to systems and control. We seek to parameterize solutions which are positive “rational” measures in a suitably generalized sense. Our parameterization is given in terms of smooth objects. In particular, the desired solution space arises naturally as a manifold which can be shown to be diffeomorphic to a Euclidean space and which is the domain of some canonically defined functions. The analysis of these functions, and related maps, yields interesting corollaries for the moment problem and its applications, which we compare to those in the recent literature and which play a crucial role in part of our proof.